Τετάρτη 31 Μαΐου 2017

A gaping research gap regarding the climate change impact on health in poor countries



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A gaping research gap regarding the climate change impact on health in poor countries



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Transient ischemic attacks on turning the head to one side, with immediate remission of symptoms when the head returned to the neutral position.



Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
6948891480

Head and neck cancer cell radiosensitization upon dual targeting of c-Abl and beta1-integrin

Integrin-mediated cell adhesion to extracellular matrix (ECM) critically contributes to cancer cell therapy resistance and DNA double strand break (DSB) repair. c-Abl tyrosine kinase has been linked to both of these processes. Based on our previous findings indicating c-Abl hyperphosphorylation on tyrosine (Y) 412 and threonine (T) 735 upon beta1-integrin inhibition, we hypothesized c-Abl tyrosine kinase as an important mediator of beta1-integrin signaling for radioresistance. In a panel of 8 cell lines from different solid cancer types grown in 3D laminin-rich ECM cultures, we targeted beta1 integrin with AIIB2 (mAb) and c-Abl with Imatinib with and without X-ray irradiation and subsequently examined clonogenic survival, residual DSBs, protein expression and phosphorylation.

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Recommendations for Childhood Cancer Screening and Surveillance in DNA Repair Disorders

DNA repair syndromes are heterogeneous disorders caused by pathogenic variants in genes encoding proteins key in DNA replication and/or the cellular response to DNA damage. The majority of these syndromes are inherited in an autosomal-recessive manner, but autosomal-dominant and X-linked recessive disorders also exist. The clinical features of patients with DNA repair syndromes are highly varied and dependent on the underlying genetic cause. Notably, all patients have elevated risks of syndrome-associated cancers, and many of these cancers present in childhood. Although it is clear that the risk of cancer is increased, there are limited data defining the true incidence of cancer and almost no evidence-based approaches to cancer surveillance in patients with DNA repair disorders. This article is the product of the October 2016 AACR Childhood Cancer Predisposition Workshop, which brought together experts from around the world to discuss and develop cancer surveillance guidelines for children with cancer-prone disorders. Herein, we focus on the more common of the rare DNA repair disorders: ataxia telangiectasia, Bloom syndrome, Fanconi anemia, dyskeratosis congenita, Nijmegen breakage syndrome, Rothmund–Thomson syndrome, and Xeroderma pigmentosum. Dedicated syndrome registries and a combination of basic science and clinical research have led to important insights into the underlying biology of these disorders. Given the rarity of these disorders, it is recommended that centralized centers of excellence be involved directly or through consultation in caring for patients with heritable DNA repair syndromes. Clin Cancer Res; 23(11); e23–e31. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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Pediatric Cancer Predisposition Imaging: Focus on Whole-Body MRI

The American Association for Cancer Research convened a meeting of international pediatric oncologists, geneticists, genetic counselors, and radiologists expert in childhood cancer predisposition syndromes (CPS) in October 2016 to propose consensus surveillance guidelines. Imaging plays a central role in surveillance for most, though not all, syndromes discussed. While encompassing the full gamut of modalities, there is increasing emphasis on use of nonionizing radiation imaging options such as magnetic resonance imaging (MRI) in children and adolescents, especially in the pediatric CPS population. In view of rapid evolution and widespread adoption of whole-body MRI (WBMRI), the purpose of our review is to address WBMRI in detail. We discuss its place in the surveillance of a range of pediatric CPS, the technical and logistical aspects of acquiring and interpreting these studies, and the inherent limitations of WBMRI. We also address issues associated with sedation and use of gadolinium-based contrast agents in MRI in children. Clin Cancer Res; 23(11); e6–e13. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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Cancer Screening Recommendations for Individuals with Li-Fraumeni Syndrome

Li-Fraumeni syndrome (LFS) is an autosomal dominantly inherited condition caused by germline mutations of the TP53 tumor suppressor gene encoding p53, a transcription factor triggered as a protective cellular mechanism against different stressors. Loss of p53 function renders affected individuals highly susceptible to a broad range of solid and hematologic cancers. It has recently become evident that children and adults with LFS benefit from intensive surveillance aimed at early tumor detection. In October 2016, the American Association for Cancer Research held a meeting of international LFS experts to evaluate the current knowledge on LFS and propose consensus surveillance recommendations. Herein, we briefly summarize clinical and genetic aspects of this aggressive cancer predisposition syndrome. In addition, the expert panel concludes that there are sufficient existing data to recommend that all patients with LFS be offered cancer surveillance as soon as the clinical or molecular LFS diagnosis is established. Specifically, the panel recommends adoption of a modified version of the "Toronto protocol" that includes a combination of physical exams, blood tests, and imaging. The panel also recommends that further research be promoted to explore the feasibility and effectiveness of these risk-adapted surveillance and cancer prevention strategies while addressing the psychosocial needs of individuals and families with LFS. Clin Cancer Res; 23(11); e38–e45. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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Recommendations for Surveillance for Children with Leukemia-Predisposing Conditions

Leukemia, the most common childhood cancer, has long been recognized to occasionally run in families. The first clues about the genetic mechanisms underlying familial leukemia emerged in 1990 when Li-Fraumeni syndrome was linked to TP53 mutations. Since this discovery, many other genes associated with hereditary predisposition to leukemia have been identified. Although several of these disorders also predispose individuals to solid tumors, certain conditions exist in which individuals are specifically at increased risk to develop myelodysplastic syndrome (MDS) and/or acute leukemia. The increasing identification of affected individuals and families has raised questions around the efficacy, timing, and optimal methods of surveillance. As part of the AACR Childhood Cancer Predisposition Workshop, an expert panel met to review the spectrum of leukemia-predisposing conditions, with the aim to develop consensus recommendations for surveillance for pediatric patients. The panel recognized that for several conditions, routine monitoring with complete blood counts and bone marrow evaluations is essential to identify disease evolution and enable early intervention with allogeneic hematopoietic stem cell transplantation. However, for others, less intensive surveillance may be considered. Because few reports describing the efficacy of surveillance exist, the recommendations derived by this panel are based on opinion, and local experience and will need to be revised over time. The development of registries and clinical trials is urgently needed to enhance understanding of the natural history of the leukemia-predisposing conditions, such that these surveillance recommendations can be optimized to further enhance long-term outcomes. Clin Cancer Res; 23(11); e14–e22. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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Clinical Management and Tumor Surveillance Recommendations of Inherited Mismatch Repair Deficiency in Childhood

Replication proofreading is crucial to avoid mutation accumulation in dividing cells. In humans, proofreading and replication repair is maintained by the exonuclease domains of DNA polymerases and the mismatch repair system. Individuals harboring germline mutations in genes involved in this process are at increased risk of early cancers from multiple organs. Biallelic mutations in any of the four mismatch repair genes MSH2, MSH6, MLH1, and PMS2 result in one of the most aggressive childhood cancer predisposition syndromes, termed constitutional mismatch repair deficiency or constitutional mismatch repair deficiency syndrome (CMMRD). Data gathered in the last decade allow us to better define the clinical manifestations, tumor spectrum, and diagnostic algorithms for CMMRD. In this article, we summarize this information and present a comprehensive consensus surveillance protocol for these individuals. Ongoing research will allow for further definition of replication repair–deficient cancer syndromes, assessing the cost-effectiveness of such surveillance protocols and potential therapeutic interventions for these children and families. Clin Cancer Res; 23(11); e32–e37. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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The Prognostic Role of Androgen Receptor in Patients with Early-Stage Breast Cancer: A Meta-analysis of Clinical and Gene Expression Data

Purpose: Androgen receptor (AR) expression has been observed in about 70% of patients with breast cancer, but its prognostic role remains uncertain.

Experimental Design: To assess the prognostic role of AR expression in early-stage breast cancer, we performed a meta-analysis of studies that evaluated the impact of AR at the protein and gene expression level on disease-free survival (DFS) and/or overall survival (OS). Eligible studies were identified by systematic review of electronic databases using the MeSH-terms "breast neoplasm" and "androgen receptor" and were selected after a qualitative assessment based on the REMARK criteria. A pooled gene expression analysis of 35 publicly available microarray data sets was also performed from patients with early-stage breast cancer with available gene expression and clinical outcome data.

Results: Twenty-two of 33 eligible studies for the clinical meta-analysis, including 10,004 patients, were considered as evaluable for the current study after the qualitative assessment. AR positivity defined by IHC was associated with improved DFS in all patients with breast cancer [multivariate (M) analysis, HR 0.46; 95% confidence interval (CI) 0.37–0.58, P < 0.001] and better OS [M-HR 0.53; 95% CI, 0.38–0.73, P < 0.001]. Thirty-five datasets including 7,220 patients were eligible for the pooled gene expression analysis. High AR mRNA levels were found to confer positive prognosis overall in terms of DFS (HR 0.82; 95% CI 0.72–0.92;P = 0.0007) and OS (HR 0.84; 95% CI, 0.75–0.94; P = 0.02) only in univariate analysis.

Conclusions: Our analysis, conducted among more than 17,000 women with early-stage breast cancer included in clinical and gene expression analysis, demonstrates that AR positivity is associated with favorable clinical outcome. Clin Cancer Res; 23(11); 2702–12. ©2016 AACR.



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Tumor-Specific Uptake of Fluorescent Bevacizumab-IRDye800CW Microdosing in Patients with Primary Breast Cancer: A Phase I Feasibility Study

Purpose: To provide proof of principle of safety, breast tumor–specific uptake, and positive tumor margin assessment of the systemically administered near-infrared fluorescent tracer bevacizumab–IRDye800CW targeting VEGF-A in patients with breast cancer.

Experimental Design: Twenty patients with primary invasive breast cancer eligible for primary surgery received 4.5 mg bevacizumab–IRDye800CW as intravenous bolus injection. Safety aspects were assessed as well as tracer uptake and tumor delineation during surgery and ex vivo in surgical specimens using an optical imaging system. Ex vivo multiplexed histopathology analyses were performed for evaluation of biodistribution of tracer uptake and coregistration of tumor tissue and healthy tissue.

Results: None of the patients experienced adverse events. Tracer levels in primary tumor tissue were higher compared with those in the tumor margin (P < 0.05) and healthy tissue (P < 0.0001). VEGF-A tumor levels also correlated with tracer levels (r = 0.63, P < 0.0002). All but one tumor showed specific tracer uptake. Two of 20 surgically excised lumps contained microscopic positive margins detected ex vivo by fluorescent macro- and microscopy and confirmed at the cellular level.

Conclusions: Our study shows that systemic administration of the bevacizumab–IRDye800CW tracer is safe for breast cancer guidance and confirms tumor and tumor margin uptake as evaluated by a systematic validation methodology. The findings are a step toward a phase II dose-finding study aimed at in vivo margin assessment and point to a novel drug assessment tool that provides a detailed picture of drug distribution in the tumor tissue. Clin Cancer Res; 23(11); 2730–41. ©2016 AACR.



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E6 and E7 Antibody Levels Are Potential Biomarkers of Recurrence in Patients with Advanced-Stage Human Papillomavirus-Positive Oropharyngeal Squamous Cell Carcinoma

Purpose: There is a paucity of biomarkers to predict failure in human papillomavirus–positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) following curative therapy. E6/E7 viral oncoproteins are constitutively expressed in HPV+ tumors and highly immunogenic, resulting in readily detected serum antibodies. The purpose of this study is to determine whether serum E6 and E7 antibody levels can potentially serve as a biomarker of recurrence in patients with HPV+OPSCC.

Experimental Design: We evaluated E6/E7 antibody levels in patients with previously untreated, advanced stage (III, IVa-b), HPV+OPSCC receiving definitive chemoradiation under a uniform protocol from 2003 to 2010. Baseline and longitudinal serum samples were obtained from our archived repository. E6/E7 serum levels were measured using a glutathione-S-transferase capture ELISA and quantified by approximating the area under the dilution curve, and were analyzed using ANOVA and linear mixed model for longitudinal analysis.

Results: We compared 22 HPV+OPSCC patients who developed recurrence with 30 patients who remained disease-free. There were no differences in T classification, N classification, disease subsite, or smoking status between the groups. In a longitudinal analysis, recurrent patients had significantly higher E6 and E7 serum antibody levels than the nonrecurrent patients over the follow-up period (P = 0.02 and P = 0.002, respectively). Patients who recurred had a lower clearance of E7 antibody than patients who remained disease-free (P = 0.0016).

Conclusions: Patients with HPV+OPSCC whose disease recurs have a lower clearance of E6 and E7 antibodies than patients who do not have recurrence. The ratio of E7 antibody at disease recurrence compared with baseline is potentially a clinically significant measurement of disease status in HPV+OPSCC. Clin Cancer Res; 23(11); 2723–9. ©2016 AACR.



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microRNA-221 Enhances MYCN via Targeting Nemo-like Kinase and Functions as an Oncogene Related to Poor Prognosis in Neuroblastoma

Purpose: MYCN is one of the most well-characterized genetic markers of neuroblastoma. However, the mechanisms as to how MYCN mediate neuroblastoma tumorigenesis are not fully clear. Increasing evidence has confirmed that the dysregulation of miRNAs is involved in MYCN-mediated neuroblastoma tumorigenesis, supporting their potential as therapeutic targets for neuroblastoma. Although miR-221 has been reported as one of the upregulated miRNAs, the interplay between miR-221 and MYCN-mediated neuroblastoma progression remains largely elusive.

Experimental Design: The expression of miR-221 in the formalin-fixed, paraffin-embedded tissues from 31 confirmed patients with neuroblastoma was detected by locked nucleic acid-in situ hybridization and qRT-PCR. The correlation between miR-221 expression and clinical features in patients with neuroblastoma was assessed. The mechanisms as to how miR-221 regulate MYCN in neuroblastoma were addressed. The effect of miR-221 on cellular proliferation in neuroblastoma was determined both in vitro and in vivo.

Results: miR-221 was significantly upregulated in neuroblastoma tumor cells and tissues that overexpress MYCN, and high expression of miR-221 was positively associated with poor survival in patients with neuroblastoma. Nemo-like kinase (NLK) as a direct target of miR-221 in neuroblastoma was verified. In addition, overexpression of miR-221 decreased LEF1 phosphorylation but increased the expression of MYCN via targeting of NLK and further regulated cell cycle, particularly in S-phase, promoting the growth of neuroblastoma cells.

Conclusions: This study provides a novel insight for miR-221 in the control of neuroblastoma cell proliferation and tumorigenesis, suggesting potentials of miR-221 as a prognosis marker and therapeutic target for patients with MYCN overexpressing neuroblastoma. Clin Cancer Res; 23(11); 2905–18. ©2016 AACR.



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Combining Anti-Mir-155 with Chemotherapy for the Treatment of Lung Cancers

Purpose: The oncogenic miR-155 is upregulated in many human cancers, and its expression is increased in more aggressive and therapy-resistant tumors, but the molecular mechanisms underlying miR-155-induced therapy resistance are not fully understood. The main objectives of this study were to determine the role of miR-155 in resistance to chemotherapy and to evaluate anti-miR-155 treatment to chemosensitize tumors.

Experimental Design: We performed in vitro studies on cell lines to investigate the role of miR-155 in therapy resistance. To assess the effects of miR-155 inhibition on chemoresistance, we used an in vivo orthotopic lung cancer model of athymic nude mice, which we treated with anti-miR-155 alone or in combination with chemotherapy. To analyze the association of miR-155 expression and the combination of miR-155 and TP53 expression with cancer survival, we studied 956 patients with lung cancer, chronic lymphocytic leukemia, and acute lymphoblastic leukemia.

Results: We demonstrate that miR-155 induces resistance to multiple chemotherapeutic agents in vitro, and that downregulation of miR-155 successfully resensitizes tumors to chemotherapy in vivo. We show that anti-miR-155-DOPC can be considered non-toxic in vivo. We further demonstrate that miR-155 and TP53 are linked in a negative feedback mechanism and that a combination of high expression of miR-155 and low expression of TP53 is significantly associated with shorter survival in lung cancer.

Conclusions: Our findings support the existence of an miR-155/TP53 feedback loop, which is involved in resistance to chemotherapy and which can be specifically targeted to overcome drug resistance, an important cause of cancer-related death. Clin Cancer Res; 23(11); 2891–904. ©2016 AACR.



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Drug-Repositioning Screens Identify Triamterene as a Selective Drug for the Treatment of DNA Mismatch Repair Deficient Cells

Purpose: The DNA mismatch repair (MMR) pathway is required for the maintenance of genome stability. Unsurprisingly, mutations in MMR genes occur in a wide range of different cancers. Studies thus far have largely focused on specific tumor types or MMR mutations; however, it is becoming increasingly clear that a therapy targeting MMR deficiency in general would be clinically very beneficial.

Experimental Design: Based on a drug-repositioning approach, we screened a large panel of cell lines with various MMR deficiencies from a range of different tumor types with a compound drug library of previously approved drugs. We have identified the potassium-sparing diuretic drug triamterene, as a novel sensitizing agent in MMR-deficient tumor cells, in vitro and in vivo.

Results: The selective tumor cell cytotoxicity of triamterene occurs through its antifolate activity and depends on the activity of the folate synthesis enzyme thymidylate synthase. Triamterene leads to a thymidylate synthase-dependent differential increase in reactive oxygen species in MMR-deficient cells, ultimately resulting in an increase in DNA double-strand breaks.

Conclusions: Conclusively, our data reveal a new drug repurposing and novel therapeutic strategy that has potential for the treatment of MMR deficiency in a range of different tumor types and could significantly improve patient survival. Clin Cancer Res; 23(11); 2880–90. ©2016 AACR.



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Disruption of Autophagic Degradation with ROC-325 Antagonizes Renal Cell Carcinoma Pathogenesis

Purpose: Although autophagy plays important roles in malignant pathogenesis and drug resistance, there are few clinical agents that disrupt this pathway, and the potential therapeutic benefit of autophagy inhibition remains undetermined. We used medicinal chemistry approaches to generate a series of novel agents that inhibit autophagic degradation.

Experimental Design: ROC-325 was selected as a lead compound for further evaluation. Comprehensive in vitro and in vivo studies were conducted to evaluate the selectivity, tolerability, and efficacy of ROC-325 in preclinical models of renal cell carcinoma (RCC) with HCQ serving as a comparator. Markers of autophagy inhibition and cell death were evaluated in tumor specimens.

Results: ROC-325 exhibited superior in vitro anticancer effects compared with the existing autophagy inhibitor hydroxychloroquine (HCQ) in 12 different cancer cell lines with diverse genetic backgrounds. Focused studies of the mechanism of action and efficacy of ROC-325 in RCC cells showed that drug treatment induced hallmark characteristics of autophagy inhibition, including accumulation of autophagosomes with undegraded cargo, lysosomal deacidification, p62 stabilization, and disruption of autophagic flux. Subsequent experiments showed that ROC-325 antagonized RCC growth and survival in an ATG5/7-dependent manner, induced apoptosis, and exhibited favorable selectivity. Oral administration of ROC-325 to mice bearing 786-0 RCC xenografts was well tolerated, was significantly more effective at inhibiting tumor progression than HCQ, and inhibited autophagy in vivo.

Conclusions: Our findings demonstrate that ROC-325 has superior preclinical anticancer activity compared with HCQ and support the clinical investigation of its safety and preliminary efficacy in patients with RCC and other autophagy-dependent malignancies. Clin Cancer Res; 23(11); 2869–79. ©2016 AACR.



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Dual ALK and CDK4/6 Inhibition Demonstrates Synergy against Neuroblastoma

Purpose: Anaplastic lymphoma kinase (ALK) is the most frequently mutated oncogene in the pediatric cancer neuroblastoma. We performed an in vitro screen for synergistic drug combinations that target neuroblastomas with mutations in ALK to determine whether drug combinations could enhance antitumor efficacy.

Experimental Design: We screened combinations of eight molecularly targeted agents against 17 comprehensively characterized human neuroblastoma-derived cell lines. We investigated the combination of ceritinib and ribociclib on in vitro proliferation, cell cycle, viability, caspase activation, and the cyclin D/CDK4/CDK6/RB and pALK signaling networks in cell lines with representative ALK status. We performed in vivo trials in CB17 SCID mice bearing conventional and patient-derived xenograft models comparing ceritinib alone, ribociclib alone, and the combination, with plasma pharmacokinetics to evaluate for drug–drug interactions.

Results: The combination of ribociclib, a dual inhibitor of cyclin-dependent kinase (CDK) 4 and 6, and the ALK inhibitor ceritinib demonstrated higher cytotoxicity (P = 0.008) and synergy scores (P = 0.006) in cell lines with ALK mutations as compared with cell lines lacking mutations or alterations in ALK. Compared with either drug alone, combination therapy enhanced growth inhibition, cell-cycle arrest, and caspase-independent cell death. Combination therapy achieved complete regressions in neuroblastoma xenografts with ALK-F1174L and F1245C de novo resistance mutations and prevented the emergence of resistance. Murine ribociclib and ceritinib plasma concentrations were unaltered by combination therapy.

Conclusions: This preclinical combination drug screen with in vivo validation has provided the rationale for a first-in-children trial of combination ceritinib and ribociclib in a molecularly selected pediatric population. Clin Cancer Res; 23(11); 2856–68. ©2016 AACR.



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Gas6/AXL Signaling Regulates Self-Renewal of Chronic Myelogenous Leukemia Stem Cells by Stabilizing {beta}-Catenin

Purpose: Quiescent leukemia stem cells (LSC) are important resources of resistance and relapse in chronic myelogenous leukemia (CML). Thus, strategies eradicating CML LSCs are required for cure. In this study, we discovered that AXL tyrosine kinase was selectively overexpressed in primary CML CD34+ cells. However, the role of AXL and its ligand Gas6 secreted by stromal cells in the regulation of self-renewal capacity of LSCs has not been well investigated.

Experimental Design: The function of CML CD34+ cells was evaluated by flow cytometer, CFC/replating, long-term culture-initiating cells (LTC-IC), CML mouse model driven by human BCR-ABL gene and NOD-scid-IL2Rg–/– (NSI) mice.

Results: AXL was selectively overexpressed in primary CML CD34+ cells. AXL knockdown reduced the survival and self-renewal capacity of human CML CD34+ cells. Pharmacologic inhibition of AXL reduced the survival and self-renewal capacity of human CML LSCs in vitro and in long-term grafts in NSI mice. Human CML CD34+ cells conscripted bone marrow–derived stromal cells (BMDSC) and primary mesenchymal stem cells (MSC) to secrete Gas6 to form a paracrine loop that promoted self-renewal of LSCs. Suppression of AXL by shRNA and inhibitor prolonged survival of CML mice and reduced the growth of LSCs in mice. Gas6/AXL ligation stabilizes β-catenin in an AKT-dependent fashion in human CML CD34+ cells.

Conclusions: Our findings improve the understanding of LSC regulation and validate Gas6/AXL as a pair of therapeutic targets to eliminate CML LSCs. Clin Cancer Res; 23(11); 2842–55. ©2016 AACR.



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Heterodimeric IL15 Treatment Enhances Tumor Infiltration, Persistence, and Effector Functions of Adoptively Transferred Tumor-specific T Cells in the Absence of Lymphodepletion

Purpose: Adoptive cell transfer (ACT) is a promising immunotherapeutic approach for cancer. Host lymphodepletion is associated with favorable ACT therapy outcomes, but it may cause detrimental effects in humans. We tested the hypothesis that IL15 administration enhances ACT in the absence of lymphodepletion. We previously showed that bioactive IL15 in vivo comprises a stable complex of the IL15 chain with the IL15 receptor alpha chain (IL15Rα), termed heterodimeric IL15 (hetIL15).

Experimental Design: We evaluated the effects of the combination regimen ACT + hetIL15 in the absence of lymphodepletion by transferring melanoma-specific Pmel-1 T cells into B16 melanoma-bearing mice.

Results: hetIL15 treatment delayed tumor growth by promoting infiltration and persistence of both adoptively transferred Pmel-1 cells and endogenous CD8+ T cells into the tumor. In contrast, persistence of Pmel-1 cells was severely reduced following irradiation in comparison with mice treated with hetIL15. Importantly, we found that hetIL15 treatment led to the preferential enrichment of Pmel-1 cells in B16 tumor sites in an antigen-dependent manner. Upon hetIL15 administration, tumor-infiltrating Pmel-1 cells showed a "nonexhausted" effector phenotype, characterized by increased IFN secretion, proliferation, and cytotoxic potential and low level of PD-1. hetIL15 treatment also resulted in an improved ratio of Pmel-1 to Treg in the tumor.

Conclusions: hetIL15 administration improves the outcome of ACT in lymphoreplete hosts, a finding with significant implications for improving cell-based cancer immunotherapy strategies. Clin Cancer Res; 23(11); 2817–30. ©2016 AACR.



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Pediatric Cancer Predisposition and Surveillance: An Overview, and a Tribute to Alfred G. Knudson Jr

The prevalence of childhood cancer attributable to genetic predisposition was generally considered very low. However, recent reports suggest that at least 10% of pediatric cancer patients harbor a germline mutation in a cancer predisposition gene. Although some of these children will have a family history suggestive of a cancer predisposition syndrome, many others will not. Evidence from recent pediatric studies suggests that surveillance and early detection of cancer in individuals carrying a germline cancer predisposing mutation may result in improved outcomes. However, there is a lack of consistency in the design of cancer surveillance regimens across centers both nationally and internationally. To standardize approaches, the Pediatric Cancer Working Group of the American Association for Cancer Research (AACR) convened a workshop, during which consensus screening recommendations for children with the most common cancer predisposition syndromes were developed. In general, we considered a 5% or greater chance of developing a childhood cancer to be a reasonable threshold to recommend screening. Conditions for which the cancer risk was between 1% to 5% were addressed individually. In a series of manuscripts accompanying this article, we provide recommendations for surveillance, focusing on when to initiate and/or discontinue specific screening measures, which modalities to use, and the frequency of screening. Points of controversy are also reviewed. We present the outcome of our deliberations on consensus screening recommendations for specific disorders in 18 position articles as Open Access publications, which are freely available on an AACR-managed website. Clin Cancer Res; 23(11); e1–e5. ©2017 AACR.

See all articles in the online-only CCR Pediatric Oncology Series.



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Phase I Study of Epigenetic Priming with Azacitidine Prior to Standard Neoadjuvant Chemotherapy for Patients with Resectable Gastric and Esophageal Adenocarcinoma: Evidence of Tumor Hypomethylation as an Indicator of Major Histopathologic Response

Purpose: Epigenetic silencing of tumor suppressor genes (TSG) is an acquired abnormality observed in cancer and is prototypically linked to DNA methylation. We postulated that pretreatment (priming) with 5-azacitidine would increase the efficacy of chemotherapy by reactivating TSGs. This study was conducted to identify a tolerable dose of 5-azacitidine prior to EOX (epirubicin, oxaliplatin, capecitabine) neoadjuvant chemotherapy in patients with locally advanced esophageal/gastric adenocarcinoma (EGC).

Experimental Design: Eligible patients had untreated, locally advanced, resectable EGC, ECOG 0–2, and adequate organ function. 5-Azacitidine (V, 75 mg/m2) was given subcutaneously for 3 (dose level, DL 1) or 5 (DL 2) days prior to each 21-day cycle of EOX (E, 50 mg/m2; O, 130 mg/m2; X, 625 mg/m2 twice daily for 21 days). Standard 3+3 methodology guided V dose escalation. DNA methylation at control and biomarker regions was measured by digital droplet, bisulfite qPCR in tumor samples collected at baseline and at resection.

Results: All subjects underwent complete resection of residual tumor (R0). Three of the 12 patients (25%) achieved a surgical complete response and 5 had partial responses. The overall response rate was 67%. The most common toxicities were gastrointestinal and hematologic. Hypomethylation of biomarker genes was observed at all dose levels and trended with therapeutic response.

Conclusions: Neoadjuvant VEOX was well-tolerated with significant clinical and epigenetic responses, with preliminary evidence that priming with V prior to chemotherapy may augment chemotherapy efficacy. The recommended phase II trial schedule is 5-azacitidine 75 mg/m2 for 5 days followed by EOX chemotherapy every 21 days. Clin Cancer Res; 23(11); 2673–80. ©2016 AACR.



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Combination Epigenetic Therapy in Advanced Breast Cancer with 5-Azacitidine and Entinostat: A Phase II National Cancer Institute/Stand Up to Cancer Study

Purpose: In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to reexpression of genes encoding important therapeutic targets, including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC).

Experimental Design: Patients received 5-azacitidine 40 mg/m2 (days 1–5, 8–10) and entinostat 7 mg (days 3, 10) on a 28-day cycle. Continuation of epigenetic therapy was offered with the addition of endocrine therapy at the time of progression [optional continuation (OC) phase]. Primary endpoint was objective response rate (ORR) in each cohort. We hypothesized that ORR would be ≥20% against null of 5% using Simon two-stage design. At least one response was required in 1 of 13 patients per cohort to continue accrual to 27 per cohort (type I error, 4%; power, 90%).

Results: There was one partial response among 27 women with hormone-resistant disease (ORR = 4%; 95% CI, 0–19), and none in 13 women with TNBC. One additional partial response was observed in the OC phase in the hormone-resistant cohort (n = 12). Mandatory tumor samples were obtained pre- and posttreatment (58% paired) with either up- or downregulation of ER observed in approximately 50% of posttreatment biopsies in the hormone-resistant, but not TNBC cohort.

Conclusions: Combination epigenetic therapy was well tolerated, but our primary endpoint was not met. OC phase results suggest that some women benefit from epigenetic therapy and/or reintroduction of endocrine therapy beyond progression, but further study is needed. Clin Cancer Res; 23(11); 2691–701. ©2016 AACR.



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Circulating Tumor Cells Expressing Markers of Tumor-Initiating Cells Predict Poor Survival and Cancer Recurrence in Patients with Pancreatic Ductal Adenocarcinoma

Purpose: Circulating tumor cells (CTCs) have been identified in the blood of patients with pancreatic adenocarcinoma (PDAC), but little is known about the exact phenotype of these cells. We assessed expression of aldehyde dehydrogenase (ALDH), CD133, and CD44 as markers of CTCs with a tumor-initiating cell (TIC) phenotype in patients with PDAC and the relationship of this expression to patient outcomes.

Experimental Design: Peripheral blood from 60 consecutive patients with PDAC undergoing surgical resection was obtained and processed using the Isolation by Size of Epithelial Tumor (ISET) method. Immunofluorescence was used to identify CTCs expressing cytokeratin, CD133, CD44, and ALDH.

Results: Forty-seven patients (78%) had epithelial CTCs staining positive for pan-cytokeratin and at least one TIC marker. Forty-six patients (77%) had epithelial CTCs that labeled with antibodies to cytokeratin and ALDH. By separate analysis, 34 (57%) had cytokeratin-positive, CD133-positive, and CD44-positive (triple-positive) CTCs, whereas 40 (67%) had cytokeratin-positive, CD133-positive, CD44-negative CTCs. The remaining 13 patients did not have CTCs, as defined by cytokeratin expression. ALDH-positive CTCs and triple-positive CTCs were significantly associated with worse survival by univariate analysis, even when accounting for other significant prognostic factors (all, P ≤ 0.01). ALDH-positive CTCs, triple-positive CTCs, and dual cytokeratin- and CD133-positive CTCs were independent predictors of tumor recurrence by logistic regression analysis and associated with decreased disease-free survival (all, P ≤ 0.03).

Conclusions: CTCs labeling with one or more markers of TICs are found in a majority of patients with PDAC and are independently predictive of decreased disease-free and overall survival. Clin Cancer Res; 23(11); 2681–90. ©2016 AACR.



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Integrative Analysis Identifies a Novel AXL-PI3 Kinase-PD-L1 Signaling Axis Associated with Radiation Resistance in Head and Neck Cancer

Purpose: The primary cause of death due to head and neck squamous cell carcinoma (HNSCC) is local treatment failure. The goal of this study was to examine this phenomenon using an unbiased approach.

Experimental Design: We utilized human papilloma virus (HPV)-negative cell lines rendered radiation-resistant (RR) via repeated exposure to radiation, a panel of HPV-negative HNSCC cell lines and three cohorts of HPV-negative HNSCC tumors (n = 68, 97, and 114) from patients treated with radiotherapy and subjected to genomic, transcriptomic, and proteomic analysis.

Results: RR cell lines exhibited upregulation of several proteins compared with controls, including increased activation of Axl and PI3 kinase signaling as well as increased expression of PD-L1. Additionally, inhibition of either Axl or PI3 kinase led to decreased PD-L1 expression. When clinical samples were subjected to RPPA and mRNA expression analysis, PD-L1 was correlated with both Axl and PI3K signaling as well as dramatically associated with local failure following radiotherapy. This finding was confirmed examining a third cohort using immunohistochemistry. Indeed, tumors with high expression of PD-L1 had failure rates following radiotherapy of 60%, 70%, and 50% compared with 20%, 25%, and 20% in the PD-L1–low expression group (P = 0.01, 1.9 x 10–3, and 9 x 10–4, respectively). This finding remained significant on multivariate analysis in all groups. Additionally, patients with PD-L1 low/CD8+ tumor-infiltrating lymphocytes high had no local failure or death due to disease (P = 5 x 10–4 and P = 4 x 10–4, respectively).

Conclusions: Taken together, our data point to a targetable Axl–PI3 kinase–PD-L1 axis that is highly associated with radiation resistance. Clin Cancer Res; 23(11); 2713–22. ©2017 AACR.



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Recommendations for Childhood Cancer Screening and Surveillance in DNA Repair Disorders

DNA repair syndromes are heterogeneous disorders caused by pathogenic variants in genes encoding proteins key in DNA replication and/or the cellular response to DNA damage. The majority of these syndromes are inherited in an autosomal-recessive manner, but autosomal-dominant and X-linked recessive disorders also exist. The clinical features of patients with DNA repair syndromes are highly varied and dependent on the underlying genetic cause. Notably, all patients have elevated risks of syndrome-associated cancers, and many of these cancers present in childhood. Although it is clear that the risk of cancer is increased, there are limited data defining the true incidence of cancer and almost no evidence-based approaches to cancer surveillance in patients with DNA repair disorders. This article is the product of the October 2016 AACR Childhood Cancer Predisposition Workshop, which brought together experts from around the world to discuss and develop cancer surveillance guidelines for children with cancer-prone disorders. Herein, we focus on the more common of the rare DNA repair disorders: ataxia telangiectasia, Bloom syndrome, Fanconi anemia, dyskeratosis congenita, Nijmegen breakage syndrome, Rothmund–Thomson syndrome, and Xeroderma pigmentosum. Dedicated syndrome registries and a combination of basic science and clinical research have led to important insights into the underlying biology of these disorders. Given the rarity of these disorders, it is recommended that centralized centers of excellence be involved directly or through consultation in caring for patients with heritable DNA repair syndromes. Clin Cancer Res; 23(11); e23–e31. ©2017 AACR.

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Pediatric Cancer Predisposition Imaging: Focus on Whole-Body MRI

The American Association for Cancer Research convened a meeting of international pediatric oncologists, geneticists, genetic counselors, and radiologists expert in childhood cancer predisposition syndromes (CPS) in October 2016 to propose consensus surveillance guidelines. Imaging plays a central role in surveillance for most, though not all, syndromes discussed. While encompassing the full gamut of modalities, there is increasing emphasis on use of nonionizing radiation imaging options such as magnetic resonance imaging (MRI) in children and adolescents, especially in the pediatric CPS population. In view of rapid evolution and widespread adoption of whole-body MRI (WBMRI), the purpose of our review is to address WBMRI in detail. We discuss its place in the surveillance of a range of pediatric CPS, the technical and logistical aspects of acquiring and interpreting these studies, and the inherent limitations of WBMRI. We also address issues associated with sedation and use of gadolinium-based contrast agents in MRI in children. Clin Cancer Res; 23(11); e6–e13. ©2017 AACR.

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Cancer Screening Recommendations for Individuals with Li-Fraumeni Syndrome

Li-Fraumeni syndrome (LFS) is an autosomal dominantly inherited condition caused by germline mutations of the TP53 tumor suppressor gene encoding p53, a transcription factor triggered as a protective cellular mechanism against different stressors. Loss of p53 function renders affected individuals highly susceptible to a broad range of solid and hematologic cancers. It has recently become evident that children and adults with LFS benefit from intensive surveillance aimed at early tumor detection. In October 2016, the American Association for Cancer Research held a meeting of international LFS experts to evaluate the current knowledge on LFS and propose consensus surveillance recommendations. Herein, we briefly summarize clinical and genetic aspects of this aggressive cancer predisposition syndrome. In addition, the expert panel concludes that there are sufficient existing data to recommend that all patients with LFS be offered cancer surveillance as soon as the clinical or molecular LFS diagnosis is established. Specifically, the panel recommends adoption of a modified version of the "Toronto protocol" that includes a combination of physical exams, blood tests, and imaging. The panel also recommends that further research be promoted to explore the feasibility and effectiveness of these risk-adapted surveillance and cancer prevention strategies while addressing the psychosocial needs of individuals and families with LFS. Clin Cancer Res; 23(11); e38–e45. ©2017 AACR.

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Recommendations for Surveillance for Children with Leukemia-Predisposing Conditions

Leukemia, the most common childhood cancer, has long been recognized to occasionally run in families. The first clues about the genetic mechanisms underlying familial leukemia emerged in 1990 when Li-Fraumeni syndrome was linked to TP53 mutations. Since this discovery, many other genes associated with hereditary predisposition to leukemia have been identified. Although several of these disorders also predispose individuals to solid tumors, certain conditions exist in which individuals are specifically at increased risk to develop myelodysplastic syndrome (MDS) and/or acute leukemia. The increasing identification of affected individuals and families has raised questions around the efficacy, timing, and optimal methods of surveillance. As part of the AACR Childhood Cancer Predisposition Workshop, an expert panel met to review the spectrum of leukemia-predisposing conditions, with the aim to develop consensus recommendations for surveillance for pediatric patients. The panel recognized that for several conditions, routine monitoring with complete blood counts and bone marrow evaluations is essential to identify disease evolution and enable early intervention with allogeneic hematopoietic stem cell transplantation. However, for others, less intensive surveillance may be considered. Because few reports describing the efficacy of surveillance exist, the recommendations derived by this panel are based on opinion, and local experience and will need to be revised over time. The development of registries and clinical trials is urgently needed to enhance understanding of the natural history of the leukemia-predisposing conditions, such that these surveillance recommendations can be optimized to further enhance long-term outcomes. Clin Cancer Res; 23(11); e14–e22. ©2017 AACR.

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Clinical Management and Tumor Surveillance Recommendations of Inherited Mismatch Repair Deficiency in Childhood

Replication proofreading is crucial to avoid mutation accumulation in dividing cells. In humans, proofreading and replication repair is maintained by the exonuclease domains of DNA polymerases and the mismatch repair system. Individuals harboring germline mutations in genes involved in this process are at increased risk of early cancers from multiple organs. Biallelic mutations in any of the four mismatch repair genes MSH2, MSH6, MLH1, and PMS2 result in one of the most aggressive childhood cancer predisposition syndromes, termed constitutional mismatch repair deficiency or constitutional mismatch repair deficiency syndrome (CMMRD). Data gathered in the last decade allow us to better define the clinical manifestations, tumor spectrum, and diagnostic algorithms for CMMRD. In this article, we summarize this information and present a comprehensive consensus surveillance protocol for these individuals. Ongoing research will allow for further definition of replication repair–deficient cancer syndromes, assessing the cost-effectiveness of such surveillance protocols and potential therapeutic interventions for these children and families. Clin Cancer Res; 23(11); e32–e37. ©2017 AACR.

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The Prognostic Role of Androgen Receptor in Patients with Early-Stage Breast Cancer: A Meta-analysis of Clinical and Gene Expression Data

Purpose: Androgen receptor (AR) expression has been observed in about 70% of patients with breast cancer, but its prognostic role remains uncertain.

Experimental Design: To assess the prognostic role of AR expression in early-stage breast cancer, we performed a meta-analysis of studies that evaluated the impact of AR at the protein and gene expression level on disease-free survival (DFS) and/or overall survival (OS). Eligible studies were identified by systematic review of electronic databases using the MeSH-terms "breast neoplasm" and "androgen receptor" and were selected after a qualitative assessment based on the REMARK criteria. A pooled gene expression analysis of 35 publicly available microarray data sets was also performed from patients with early-stage breast cancer with available gene expression and clinical outcome data.

Results: Twenty-two of 33 eligible studies for the clinical meta-analysis, including 10,004 patients, were considered as evaluable for the current study after the qualitative assessment. AR positivity defined by IHC was associated with improved DFS in all patients with breast cancer [multivariate (M) analysis, HR 0.46; 95% confidence interval (CI) 0.37–0.58, P < 0.001] and better OS [M-HR 0.53; 95% CI, 0.38–0.73, P < 0.001]. Thirty-five datasets including 7,220 patients were eligible for the pooled gene expression analysis. High AR mRNA levels were found to confer positive prognosis overall in terms of DFS (HR 0.82; 95% CI 0.72–0.92;P = 0.0007) and OS (HR 0.84; 95% CI, 0.75–0.94; P = 0.02) only in univariate analysis.

Conclusions: Our analysis, conducted among more than 17,000 women with early-stage breast cancer included in clinical and gene expression analysis, demonstrates that AR positivity is associated with favorable clinical outcome. Clin Cancer Res; 23(11); 2702–12. ©2016 AACR.



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Tumor-Specific Uptake of Fluorescent Bevacizumab-IRDye800CW Microdosing in Patients with Primary Breast Cancer: A Phase I Feasibility Study

Purpose: To provide proof of principle of safety, breast tumor–specific uptake, and positive tumor margin assessment of the systemically administered near-infrared fluorescent tracer bevacizumab–IRDye800CW targeting VEGF-A in patients with breast cancer.

Experimental Design: Twenty patients with primary invasive breast cancer eligible for primary surgery received 4.5 mg bevacizumab–IRDye800CW as intravenous bolus injection. Safety aspects were assessed as well as tracer uptake and tumor delineation during surgery and ex vivo in surgical specimens using an optical imaging system. Ex vivo multiplexed histopathology analyses were performed for evaluation of biodistribution of tracer uptake and coregistration of tumor tissue and healthy tissue.

Results: None of the patients experienced adverse events. Tracer levels in primary tumor tissue were higher compared with those in the tumor margin (P < 0.05) and healthy tissue (P < 0.0001). VEGF-A tumor levels also correlated with tracer levels (r = 0.63, P < 0.0002). All but one tumor showed specific tracer uptake. Two of 20 surgically excised lumps contained microscopic positive margins detected ex vivo by fluorescent macro- and microscopy and confirmed at the cellular level.

Conclusions: Our study shows that systemic administration of the bevacizumab–IRDye800CW tracer is safe for breast cancer guidance and confirms tumor and tumor margin uptake as evaluated by a systematic validation methodology. The findings are a step toward a phase II dose-finding study aimed at in vivo margin assessment and point to a novel drug assessment tool that provides a detailed picture of drug distribution in the tumor tissue. Clin Cancer Res; 23(11); 2730–41. ©2016 AACR.



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E6 and E7 Antibody Levels Are Potential Biomarkers of Recurrence in Patients with Advanced-Stage Human Papillomavirus-Positive Oropharyngeal Squamous Cell Carcinoma

Purpose: There is a paucity of biomarkers to predict failure in human papillomavirus–positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) following curative therapy. E6/E7 viral oncoproteins are constitutively expressed in HPV+ tumors and highly immunogenic, resulting in readily detected serum antibodies. The purpose of this study is to determine whether serum E6 and E7 antibody levels can potentially serve as a biomarker of recurrence in patients with HPV+OPSCC.

Experimental Design: We evaluated E6/E7 antibody levels in patients with previously untreated, advanced stage (III, IVa-b), HPV+OPSCC receiving definitive chemoradiation under a uniform protocol from 2003 to 2010. Baseline and longitudinal serum samples were obtained from our archived repository. E6/E7 serum levels were measured using a glutathione-S-transferase capture ELISA and quantified by approximating the area under the dilution curve, and were analyzed using ANOVA and linear mixed model for longitudinal analysis.

Results: We compared 22 HPV+OPSCC patients who developed recurrence with 30 patients who remained disease-free. There were no differences in T classification, N classification, disease subsite, or smoking status between the groups. In a longitudinal analysis, recurrent patients had significantly higher E6 and E7 serum antibody levels than the nonrecurrent patients over the follow-up period (P = 0.02 and P = 0.002, respectively). Patients who recurred had a lower clearance of E7 antibody than patients who remained disease-free (P = 0.0016).

Conclusions: Patients with HPV+OPSCC whose disease recurs have a lower clearance of E6 and E7 antibodies than patients who do not have recurrence. The ratio of E7 antibody at disease recurrence compared with baseline is potentially a clinically significant measurement of disease status in HPV+OPSCC. Clin Cancer Res; 23(11); 2723–9. ©2016 AACR.



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microRNA-221 Enhances MYCN via Targeting Nemo-like Kinase and Functions as an Oncogene Related to Poor Prognosis in Neuroblastoma

Purpose: MYCN is one of the most well-characterized genetic markers of neuroblastoma. However, the mechanisms as to how MYCN mediate neuroblastoma tumorigenesis are not fully clear. Increasing evidence has confirmed that the dysregulation of miRNAs is involved in MYCN-mediated neuroblastoma tumorigenesis, supporting their potential as therapeutic targets for neuroblastoma. Although miR-221 has been reported as one of the upregulated miRNAs, the interplay between miR-221 and MYCN-mediated neuroblastoma progression remains largely elusive.

Experimental Design: The expression of miR-221 in the formalin-fixed, paraffin-embedded tissues from 31 confirmed patients with neuroblastoma was detected by locked nucleic acid-in situ hybridization and qRT-PCR. The correlation between miR-221 expression and clinical features in patients with neuroblastoma was assessed. The mechanisms as to how miR-221 regulate MYCN in neuroblastoma were addressed. The effect of miR-221 on cellular proliferation in neuroblastoma was determined both in vitro and in vivo.

Results: miR-221 was significantly upregulated in neuroblastoma tumor cells and tissues that overexpress MYCN, and high expression of miR-221 was positively associated with poor survival in patients with neuroblastoma. Nemo-like kinase (NLK) as a direct target of miR-221 in neuroblastoma was verified. In addition, overexpression of miR-221 decreased LEF1 phosphorylation but increased the expression of MYCN via targeting of NLK and further regulated cell cycle, particularly in S-phase, promoting the growth of neuroblastoma cells.

Conclusions: This study provides a novel insight for miR-221 in the control of neuroblastoma cell proliferation and tumorigenesis, suggesting potentials of miR-221 as a prognosis marker and therapeutic target for patients with MYCN overexpressing neuroblastoma. Clin Cancer Res; 23(11); 2905–18. ©2016 AACR.



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Combining Anti-Mir-155 with Chemotherapy for the Treatment of Lung Cancers

Purpose: The oncogenic miR-155 is upregulated in many human cancers, and its expression is increased in more aggressive and therapy-resistant tumors, but the molecular mechanisms underlying miR-155-induced therapy resistance are not fully understood. The main objectives of this study were to determine the role of miR-155 in resistance to chemotherapy and to evaluate anti-miR-155 treatment to chemosensitize tumors.

Experimental Design: We performed in vitro studies on cell lines to investigate the role of miR-155 in therapy resistance. To assess the effects of miR-155 inhibition on chemoresistance, we used an in vivo orthotopic lung cancer model of athymic nude mice, which we treated with anti-miR-155 alone or in combination with chemotherapy. To analyze the association of miR-155 expression and the combination of miR-155 and TP53 expression with cancer survival, we studied 956 patients with lung cancer, chronic lymphocytic leukemia, and acute lymphoblastic leukemia.

Results: We demonstrate that miR-155 induces resistance to multiple chemotherapeutic agents in vitro, and that downregulation of miR-155 successfully resensitizes tumors to chemotherapy in vivo. We show that anti-miR-155-DOPC can be considered non-toxic in vivo. We further demonstrate that miR-155 and TP53 are linked in a negative feedback mechanism and that a combination of high expression of miR-155 and low expression of TP53 is significantly associated with shorter survival in lung cancer.

Conclusions: Our findings support the existence of an miR-155/TP53 feedback loop, which is involved in resistance to chemotherapy and which can be specifically targeted to overcome drug resistance, an important cause of cancer-related death. Clin Cancer Res; 23(11); 2891–904. ©2016 AACR.



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Drug-Repositioning Screens Identify Triamterene as a Selective Drug for the Treatment of DNA Mismatch Repair Deficient Cells

Purpose: The DNA mismatch repair (MMR) pathway is required for the maintenance of genome stability. Unsurprisingly, mutations in MMR genes occur in a wide range of different cancers. Studies thus far have largely focused on specific tumor types or MMR mutations; however, it is becoming increasingly clear that a therapy targeting MMR deficiency in general would be clinically very beneficial.

Experimental Design: Based on a drug-repositioning approach, we screened a large panel of cell lines with various MMR deficiencies from a range of different tumor types with a compound drug library of previously approved drugs. We have identified the potassium-sparing diuretic drug triamterene, as a novel sensitizing agent in MMR-deficient tumor cells, in vitro and in vivo.

Results: The selective tumor cell cytotoxicity of triamterene occurs through its antifolate activity and depends on the activity of the folate synthesis enzyme thymidylate synthase. Triamterene leads to a thymidylate synthase-dependent differential increase in reactive oxygen species in MMR-deficient cells, ultimately resulting in an increase in DNA double-strand breaks.

Conclusions: Conclusively, our data reveal a new drug repurposing and novel therapeutic strategy that has potential for the treatment of MMR deficiency in a range of different tumor types and could significantly improve patient survival. Clin Cancer Res; 23(11); 2880–90. ©2016 AACR.



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Disruption of Autophagic Degradation with ROC-325 Antagonizes Renal Cell Carcinoma Pathogenesis

Purpose: Although autophagy plays important roles in malignant pathogenesis and drug resistance, there are few clinical agents that disrupt this pathway, and the potential therapeutic benefit of autophagy inhibition remains undetermined. We used medicinal chemistry approaches to generate a series of novel agents that inhibit autophagic degradation.

Experimental Design: ROC-325 was selected as a lead compound for further evaluation. Comprehensive in vitro and in vivo studies were conducted to evaluate the selectivity, tolerability, and efficacy of ROC-325 in preclinical models of renal cell carcinoma (RCC) with HCQ serving as a comparator. Markers of autophagy inhibition and cell death were evaluated in tumor specimens.

Results: ROC-325 exhibited superior in vitro anticancer effects compared with the existing autophagy inhibitor hydroxychloroquine (HCQ) in 12 different cancer cell lines with diverse genetic backgrounds. Focused studies of the mechanism of action and efficacy of ROC-325 in RCC cells showed that drug treatment induced hallmark characteristics of autophagy inhibition, including accumulation of autophagosomes with undegraded cargo, lysosomal deacidification, p62 stabilization, and disruption of autophagic flux. Subsequent experiments showed that ROC-325 antagonized RCC growth and survival in an ATG5/7-dependent manner, induced apoptosis, and exhibited favorable selectivity. Oral administration of ROC-325 to mice bearing 786-0 RCC xenografts was well tolerated, was significantly more effective at inhibiting tumor progression than HCQ, and inhibited autophagy in vivo.

Conclusions: Our findings demonstrate that ROC-325 has superior preclinical anticancer activity compared with HCQ and support the clinical investigation of its safety and preliminary efficacy in patients with RCC and other autophagy-dependent malignancies. Clin Cancer Res; 23(11); 2869–79. ©2016 AACR.



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Dual ALK and CDK4/6 Inhibition Demonstrates Synergy against Neuroblastoma

Purpose: Anaplastic lymphoma kinase (ALK) is the most frequently mutated oncogene in the pediatric cancer neuroblastoma. We performed an in vitro screen for synergistic drug combinations that target neuroblastomas with mutations in ALK to determine whether drug combinations could enhance antitumor efficacy.

Experimental Design: We screened combinations of eight molecularly targeted agents against 17 comprehensively characterized human neuroblastoma-derived cell lines. We investigated the combination of ceritinib and ribociclib on in vitro proliferation, cell cycle, viability, caspase activation, and the cyclin D/CDK4/CDK6/RB and pALK signaling networks in cell lines with representative ALK status. We performed in vivo trials in CB17 SCID mice bearing conventional and patient-derived xenograft models comparing ceritinib alone, ribociclib alone, and the combination, with plasma pharmacokinetics to evaluate for drug–drug interactions.

Results: The combination of ribociclib, a dual inhibitor of cyclin-dependent kinase (CDK) 4 and 6, and the ALK inhibitor ceritinib demonstrated higher cytotoxicity (P = 0.008) and synergy scores (P = 0.006) in cell lines with ALK mutations as compared with cell lines lacking mutations or alterations in ALK. Compared with either drug alone, combination therapy enhanced growth inhibition, cell-cycle arrest, and caspase-independent cell death. Combination therapy achieved complete regressions in neuroblastoma xenografts with ALK-F1174L and F1245C de novo resistance mutations and prevented the emergence of resistance. Murine ribociclib and ceritinib plasma concentrations were unaltered by combination therapy.

Conclusions: This preclinical combination drug screen with in vivo validation has provided the rationale for a first-in-children trial of combination ceritinib and ribociclib in a molecularly selected pediatric population. Clin Cancer Res; 23(11); 2856–68. ©2016 AACR.



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Gas6/AXL Signaling Regulates Self-Renewal of Chronic Myelogenous Leukemia Stem Cells by Stabilizing {beta}-Catenin

Purpose: Quiescent leukemia stem cells (LSC) are important resources of resistance and relapse in chronic myelogenous leukemia (CML). Thus, strategies eradicating CML LSCs are required for cure. In this study, we discovered that AXL tyrosine kinase was selectively overexpressed in primary CML CD34+ cells. However, the role of AXL and its ligand Gas6 secreted by stromal cells in the regulation of self-renewal capacity of LSCs has not been well investigated.

Experimental Design: The function of CML CD34+ cells was evaluated by flow cytometer, CFC/replating, long-term culture-initiating cells (LTC-IC), CML mouse model driven by human BCR-ABL gene and NOD-scid-IL2Rg–/– (NSI) mice.

Results: AXL was selectively overexpressed in primary CML CD34+ cells. AXL knockdown reduced the survival and self-renewal capacity of human CML CD34+ cells. Pharmacologic inhibition of AXL reduced the survival and self-renewal capacity of human CML LSCs in vitro and in long-term grafts in NSI mice. Human CML CD34+ cells conscripted bone marrow–derived stromal cells (BMDSC) and primary mesenchymal stem cells (MSC) to secrete Gas6 to form a paracrine loop that promoted self-renewal of LSCs. Suppression of AXL by shRNA and inhibitor prolonged survival of CML mice and reduced the growth of LSCs in mice. Gas6/AXL ligation stabilizes β-catenin in an AKT-dependent fashion in human CML CD34+ cells.

Conclusions: Our findings improve the understanding of LSC regulation and validate Gas6/AXL as a pair of therapeutic targets to eliminate CML LSCs. Clin Cancer Res; 23(11); 2842–55. ©2016 AACR.



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Heterodimeric IL15 Treatment Enhances Tumor Infiltration, Persistence, and Effector Functions of Adoptively Transferred Tumor-specific T Cells in the Absence of Lymphodepletion

Purpose: Adoptive cell transfer (ACT) is a promising immunotherapeutic approach for cancer. Host lymphodepletion is associated with favorable ACT therapy outcomes, but it may cause detrimental effects in humans. We tested the hypothesis that IL15 administration enhances ACT in the absence of lymphodepletion. We previously showed that bioactive IL15 in vivo comprises a stable complex of the IL15 chain with the IL15 receptor alpha chain (IL15Rα), termed heterodimeric IL15 (hetIL15).

Experimental Design: We evaluated the effects of the combination regimen ACT + hetIL15 in the absence of lymphodepletion by transferring melanoma-specific Pmel-1 T cells into B16 melanoma-bearing mice.

Results: hetIL15 treatment delayed tumor growth by promoting infiltration and persistence of both adoptively transferred Pmel-1 cells and endogenous CD8+ T cells into the tumor. In contrast, persistence of Pmel-1 cells was severely reduced following irradiation in comparison with mice treated with hetIL15. Importantly, we found that hetIL15 treatment led to the preferential enrichment of Pmel-1 cells in B16 tumor sites in an antigen-dependent manner. Upon hetIL15 administration, tumor-infiltrating Pmel-1 cells showed a "nonexhausted" effector phenotype, characterized by increased IFN secretion, proliferation, and cytotoxic potential and low level of PD-1. hetIL15 treatment also resulted in an improved ratio of Pmel-1 to Treg in the tumor.

Conclusions: hetIL15 administration improves the outcome of ACT in lymphoreplete hosts, a finding with significant implications for improving cell-based cancer immunotherapy strategies. Clin Cancer Res; 23(11); 2817–30. ©2016 AACR.



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Pediatric Cancer Predisposition and Surveillance: An Overview, and a Tribute to Alfred G. Knudson Jr

The prevalence of childhood cancer attributable to genetic predisposition was generally considered very low. However, recent reports suggest that at least 10% of pediatric cancer patients harbor a germline mutation in a cancer predisposition gene. Although some of these children will have a family history suggestive of a cancer predisposition syndrome, many others will not. Evidence from recent pediatric studies suggests that surveillance and early detection of cancer in individuals carrying a germline cancer predisposing mutation may result in improved outcomes. However, there is a lack of consistency in the design of cancer surveillance regimens across centers both nationally and internationally. To standardize approaches, the Pediatric Cancer Working Group of the American Association for Cancer Research (AACR) convened a workshop, during which consensus screening recommendations for children with the most common cancer predisposition syndromes were developed. In general, we considered a 5% or greater chance of developing a childhood cancer to be a reasonable threshold to recommend screening. Conditions for which the cancer risk was between 1% to 5% were addressed individually. In a series of manuscripts accompanying this article, we provide recommendations for surveillance, focusing on when to initiate and/or discontinue specific screening measures, which modalities to use, and the frequency of screening. Points of controversy are also reviewed. We present the outcome of our deliberations on consensus screening recommendations for specific disorders in 18 position articles as Open Access publications, which are freely available on an AACR-managed website. Clin Cancer Res; 23(11); e1–e5. ©2017 AACR.

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Phase I Study of Epigenetic Priming with Azacitidine Prior to Standard Neoadjuvant Chemotherapy for Patients with Resectable Gastric and Esophageal Adenocarcinoma: Evidence of Tumor Hypomethylation as an Indicator of Major Histopathologic Response

Purpose: Epigenetic silencing of tumor suppressor genes (TSG) is an acquired abnormality observed in cancer and is prototypically linked to DNA methylation. We postulated that pretreatment (priming) with 5-azacitidine would increase the efficacy of chemotherapy by reactivating TSGs. This study was conducted to identify a tolerable dose of 5-azacitidine prior to EOX (epirubicin, oxaliplatin, capecitabine) neoadjuvant chemotherapy in patients with locally advanced esophageal/gastric adenocarcinoma (EGC).

Experimental Design: Eligible patients had untreated, locally advanced, resectable EGC, ECOG 0–2, and adequate organ function. 5-Azacitidine (V, 75 mg/m2) was given subcutaneously for 3 (dose level, DL 1) or 5 (DL 2) days prior to each 21-day cycle of EOX (E, 50 mg/m2; O, 130 mg/m2; X, 625 mg/m2 twice daily for 21 days). Standard 3+3 methodology guided V dose escalation. DNA methylation at control and biomarker regions was measured by digital droplet, bisulfite qPCR in tumor samples collected at baseline and at resection.

Results: All subjects underwent complete resection of residual tumor (R0). Three of the 12 patients (25%) achieved a surgical complete response and 5 had partial responses. The overall response rate was 67%. The most common toxicities were gastrointestinal and hematologic. Hypomethylation of biomarker genes was observed at all dose levels and trended with therapeutic response.

Conclusions: Neoadjuvant VEOX was well-tolerated with significant clinical and epigenetic responses, with preliminary evidence that priming with V prior to chemotherapy may augment chemotherapy efficacy. The recommended phase II trial schedule is 5-azacitidine 75 mg/m2 for 5 days followed by EOX chemotherapy every 21 days. Clin Cancer Res; 23(11); 2673–80. ©2016 AACR.



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Combination Epigenetic Therapy in Advanced Breast Cancer with 5-Azacitidine and Entinostat: A Phase II National Cancer Institute/Stand Up to Cancer Study

Purpose: In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to reexpression of genes encoding important therapeutic targets, including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC).

Experimental Design: Patients received 5-azacitidine 40 mg/m2 (days 1–5, 8–10) and entinostat 7 mg (days 3, 10) on a 28-day cycle. Continuation of epigenetic therapy was offered with the addition of endocrine therapy at the time of progression [optional continuation (OC) phase]. Primary endpoint was objective response rate (ORR) in each cohort. We hypothesized that ORR would be ≥20% against null of 5% using Simon two-stage design. At least one response was required in 1 of 13 patients per cohort to continue accrual to 27 per cohort (type I error, 4%; power, 90%).

Results: There was one partial response among 27 women with hormone-resistant disease (ORR = 4%; 95% CI, 0–19), and none in 13 women with TNBC. One additional partial response was observed in the OC phase in the hormone-resistant cohort (n = 12). Mandatory tumor samples were obtained pre- and posttreatment (58% paired) with either up- or downregulation of ER observed in approximately 50% of posttreatment biopsies in the hormone-resistant, but not TNBC cohort.

Conclusions: Combination epigenetic therapy was well tolerated, but our primary endpoint was not met. OC phase results suggest that some women benefit from epigenetic therapy and/or reintroduction of endocrine therapy beyond progression, but further study is needed. Clin Cancer Res; 23(11); 2691–701. ©2016 AACR.



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Circulating Tumor Cells Expressing Markers of Tumor-Initiating Cells Predict Poor Survival and Cancer Recurrence in Patients with Pancreatic Ductal Adenocarcinoma

Purpose: Circulating tumor cells (CTCs) have been identified in the blood of patients with pancreatic adenocarcinoma (PDAC), but little is known about the exact phenotype of these cells. We assessed expression of aldehyde dehydrogenase (ALDH), CD133, and CD44 as markers of CTCs with a tumor-initiating cell (TIC) phenotype in patients with PDAC and the relationship of this expression to patient outcomes.

Experimental Design: Peripheral blood from 60 consecutive patients with PDAC undergoing surgical resection was obtained and processed using the Isolation by Size of Epithelial Tumor (ISET) method. Immunofluorescence was used to identify CTCs expressing cytokeratin, CD133, CD44, and ALDH.

Results: Forty-seven patients (78%) had epithelial CTCs staining positive for pan-cytokeratin and at least one TIC marker. Forty-six patients (77%) had epithelial CTCs that labeled with antibodies to cytokeratin and ALDH. By separate analysis, 34 (57%) had cytokeratin-positive, CD133-positive, and CD44-positive (triple-positive) CTCs, whereas 40 (67%) had cytokeratin-positive, CD133-positive, CD44-negative CTCs. The remaining 13 patients did not have CTCs, as defined by cytokeratin expression. ALDH-positive CTCs and triple-positive CTCs were significantly associated with worse survival by univariate analysis, even when accounting for other significant prognostic factors (all, P ≤ 0.01). ALDH-positive CTCs, triple-positive CTCs, and dual cytokeratin- and CD133-positive CTCs were independent predictors of tumor recurrence by logistic regression analysis and associated with decreased disease-free survival (all, P ≤ 0.03).

Conclusions: CTCs labeling with one or more markers of TICs are found in a majority of patients with PDAC and are independently predictive of decreased disease-free and overall survival. Clin Cancer Res; 23(11); 2681–90. ©2016 AACR.



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Integrative Analysis Identifies a Novel AXL-PI3 Kinase-PD-L1 Signaling Axis Associated with Radiation Resistance in Head and Neck Cancer

Purpose: The primary cause of death due to head and neck squamous cell carcinoma (HNSCC) is local treatment failure. The goal of this study was to examine this phenomenon using an unbiased approach.

Experimental Design: We utilized human papilloma virus (HPV)-negative cell lines rendered radiation-resistant (RR) via repeated exposure to radiation, a panel of HPV-negative HNSCC cell lines and three cohorts of HPV-negative HNSCC tumors (n = 68, 97, and 114) from patients treated with radiotherapy and subjected to genomic, transcriptomic, and proteomic analysis.

Results: RR cell lines exhibited upregulation of several proteins compared with controls, including increased activation of Axl and PI3 kinase signaling as well as increased expression of PD-L1. Additionally, inhibition of either Axl or PI3 kinase led to decreased PD-L1 expression. When clinical samples were subjected to RPPA and mRNA expression analysis, PD-L1 was correlated with both Axl and PI3K signaling as well as dramatically associated with local failure following radiotherapy. This finding was confirmed examining a third cohort using immunohistochemistry. Indeed, tumors with high expression of PD-L1 had failure rates following radiotherapy of 60%, 70%, and 50% compared with 20%, 25%, and 20% in the PD-L1–low expression group (P = 0.01, 1.9 x 10–3, and 9 x 10–4, respectively). This finding remained significant on multivariate analysis in all groups. Additionally, patients with PD-L1 low/CD8+ tumor-infiltrating lymphocytes high had no local failure or death due to disease (P = 5 x 10–4 and P = 4 x 10–4, respectively).

Conclusions: Taken together, our data point to a targetable Axl–PI3 kinase–PD-L1 axis that is highly associated with radiation resistance. Clin Cancer Res; 23(11); 2713–22. ©2017 AACR.



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A PET Imaging Strategy to Visualize Activated T Cells in Acute Graft-versus-Host Disease Elicited by Allogenic Hematopoietic Cell Transplant

A major barrier to successful use of allogeneic hematopoietic cell transplantation is acute graft-versus-host disease (aGVHD), a devastating condition that arises when donor T cells attack host tissues. With current technologies, aGVHD diagnosis is typically made after end-organ injury and often requires invasive tests and tissue biopsies. This affects patient prognosis as treatments are dramatically less effective at late disease stages. Here, we show that a novel PET radiotracer, 2′-deoxy-2′-[18F]fluoro-9-β-D-arabinofuranosylguanine ([18F]F-AraG), targeted toward two salvage kinase pathways preferentially accumulates in activated primary T cells. [18F]F-AraG PET imaging of a murine aGVHD model enabled visualization of secondary lymphoid organs harboring activated donor T cells prior to clinical symptoms. Tracer biodistribution in healthy humans showed favorable kinetics. This new PET strategy has great potential for early aGVHD diagnosis, enabling timely treatments and improved patient outcomes. [18F]F-AraG may be useful for imaging activated T cells in various biomedical applications. Cancer Res; 77(11); 2893–902. ©2017 AACR.

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Cellular Prion Protein PrPC and Ecto-5'-Nucleotidase Are Markers of the Cellular Stress Response to Aneuploidy

Aneuploidy is a hallmark of most human tumors, but the molecular physiology of aneuploid cells is not well characterized. In this study, we screened cell surface biomarkers of approximately 300 proteins by multiparameter flow cytometry using multiple aneuploid model systems such as cell lines, patient samples, and mouse models. Several new biomarkers were identified with altered expression in aneuploid cells, including overexpression of the cellular prion protein CD230/PrPC and the immunosuppressive cell surface enzyme ecto-5′-nucleotidase CD73. Functional analyses associated these alterations with increased cellular stress. An increased number of CD73+ cells was observed in confluent cultures in aneuploid cells relative to their diploid counterparts. An elevated expression in CD230/PrPC was observed in serum-deprived cells in association with increased generation of reactive oxygen species. Overall, our work identified biomarkers of aneuploid karyotypes, which suggest insights into the underlying molecular physiology of aneuploid cells. Cancer Res; 77(11); 2914–26. ©2017 AACR.

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CIC-DUX4 Induces Small Round Cell Sarcomas Distinct from Ewing Sarcoma

CIC-DUX4 sarcoma (CDS) or CIC-rearranged sarcoma is a subcategory of small round cell sarcoma resembling the morphological phenotypes of Ewing sarcoma (ES). However, recent clinicopathologic and molecular genetic analyses indicate that CDS is an independent disease entity from ES. Few ancillary markers have been used in the differential diagnosis of CDS, and additional CDS-specific biomarkers are needed for more definitive classification. Here, we report the generation of an ex vivo mouse model for CDS by transducing embryonic mesenchymal cells (eMC) with human CIC-DUX4 cDNA. Recipient mice transplanted with eMC-expressing CIC-DUX4 rapidly developed an aggressive, undifferentiated sarcoma composed of small round to short spindle cells. Gene-expression profiles of CDS and eMC revealed upregulation of CIC-DUX4 downstream genes such as PEA3 family genes, Ccnd2, Crh, and Zic1. IHC analyses for both mouse and human tumors showed that CCND2 and MUC5AC are reliable biomarkers to distinguish CDS from ES. Gene silencing of CIC-DUX4 as well as Ccnd2, Ret, and Bcl2 effectively inhibited CDS tumor growth in vitro. The CDK4/6 inhibitor palbociclib and the soft tissue sarcoma drug trabectedin also blocked the growth of mouse CDS. In summary, our mouse model provides important biological information about CDS and provides a useful platform to explore biomarkers and therapeutic agents for CDS. Cancer Res; 77(11); 2927–37. ©2017 AACR.

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Multidrug Analyses in Patients Distinguish Efficacious Cancer Agents Based on Both Tumor Cell Killing and Immunomodulation

The vision of a precision medicine–guided approach to novel cancer drug development is challenged by high intratumor heterogeneity and interpatient diversity. This complexity is rarely modeled accurately during preclinical drug development, hampering predictions of clinical drug efficacy. To address this issue, we developed Comparative In Vivo Oncology (CIVO) arrayed microinjection technology to test tumor responsiveness to simultaneous microdoses of multiple drugs directly in a patient's tumor. Here, in a study of 18 canine patients with soft tissue sarcoma (STS), CIVO captured complex, patient-specific tumor responses encompassing both cancer cells and multiple immune infiltrates following localized exposure to different chemotherapy agents. CIVO also classified patient-specific tumor resistance to the most effective agent, doxorubicin, and further enabled assessment of a preclinical autophagy inhibitor, PS-1001, to reverse doxorubicin resistance. In a CIVO-identified subset of doxorubicin-resistant tumors, PS-1001 resulted in enhanced antitumor activity, increased infiltration of macrophages, and skewed this infiltrate toward M1 polarization. The ability to evaluate and cross-compare multiple drugs and drug combinations simultaneously in living tumors and across a diverse immunocompetent patient population may provide a foundation from which to make informed drug development decisions. This method also represents a viable functional approach to complement current precision oncology strategies. Cancer Res; 77(11); 2869–80. ©2017 AACR.

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Spermidine Prolongs Lifespan and Prevents Liver Fibrosis and Hepatocellular Carcinoma by Activating MAP1S-Mediated Autophagy

Liver fibrosis and hepatocellular carcinoma (HCC) have worldwide impact but continue to lack safe, low cost, and effective treatments. In this study, we show how the simple polyamine spermidine can relieve cancer cell defects in autophagy, which trigger oxidative stress–induced cell death and promote liver fibrosis and HCC. We found that the autophagic marker protein LC3 interacted with the microtubule-associated protein MAP1S, which positively regulated autophagy flux in cells. MAP1S stability was regulated in turn by its interaction with the histone deacetylase HDAC4. Notably, MAP1S-deficient mice exhibited a 20% reduction in median survival and developed severe liver fibrosis and HCC under stress. Wild-type mice or cells treated with spermidine exhibited a relative increase in MAP1S stability and autophagy signaling via depletion of cytosolic HDAC4. Extending recent evidence that orally administered spermidine can extend lifespan in mice, we determined that life extension of up to 25% can be produced by lifelong administration, which also reduced liver fibrosis and HCC foci as induced by chemical insults. Genetic investigations established that these observed impacts of oral spermidine administration relied upon MAP1S-mediated autophagy. Our findings offer a preclinical proof of concept for the administration of oral spermidine to prevent liver fibrosis and HCC and potentially extend lifespan. Cancer Res; 77(11); 2938–51. ©2017 AACR.

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NRF2 Induction Supporting Breast Cancer Cell Survival Is Enabled by Oxidative Stress-Induced DPP3-KEAP1 Interaction

NRF2 is a transcription factor serving as a master regulator of the expression of many genes involved in cellular responses to oxidative and other stresses. In the absence of stress, NRF2 is constantly synthesized but maintained at low levels as it is targeted by KEAP1 for ubiquitination and proteasome-mediated degradation. NRF2 binds KEAP1 mainly through a conserved "ETGE" motif that has also been found in several other proteins, such as DPP3, which has been shown to bind KEAP1 and enhance NRF2 function upon overexpression. Here we demonstrate the interaction between endogenous DPP3 and endogenous KEAP1. We further show that the DPP3–KEAP1 interaction is strongly induced by hydrogen peroxide and that DPP3 is required for timely NRF2 induction and nuclear accumulation in the estrogen receptor (ER)-positive MCF7 breast cancer cells. Moreover, we present evidence that the binding of DPP3 to KEAP1 stabilizes the latter. Finally, we show that DPP3 is overexpressed in breast cancer and that elevated levels of DPP3 mRNA correlate with increased NRF2 downstream gene expression and poor prognosis, particularly for ER-positive breast cancer. Our studies reveal novel insights into the regulation of NRF2 and identify DPP3 and an NRF2 transcriptional signature as potential biomarkers for breast cancer prognosis and treatment. Cancer Res; 77(11); 2881–92. ©2017 AACR.

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Metabolic Markers and Statistical Prediction of Serous Ovarian Cancer Aggressiveness by Ambient Ionization Mass Spectrometry Imaging

Ovarian high-grade serous carcinoma (HGSC) results in the highest mortality among gynecological cancers, developing rapidly and aggressively. Dissimilarly, serous borderline ovarian tumors (BOT) can progress into low-grade serous carcinomas and have relatively indolent clinical behavior. The underlying biological differences between HGSC and BOT call for accurate diagnostic methodologies and tailored treatment options, and identification of molecular markers of aggressiveness could provide valuable biochemical insights and improve disease management. Here, we used desorption electrospray ionization (DESI) mass spectrometry (MS) to image and chemically characterize the metabolic profiles of HGSC, BOT, and normal ovarian tissue samples. DESI-MS imaging enabled clear visualization of fine papillary branches in serous BOT and allowed for characterization of spatial features of tumor heterogeneity such as adjacent necrosis and stroma in HGSC. Predictive markers of cancer aggressiveness were identified, including various free fatty acids, metabolites, and complex lipids such as ceramides, glycerophosphoglycerols, cardiolipins, and glycerophosphocholines. Classification models built from a total of 89,826 individual pixels, acquired in positive and negative ion modes from 78 different tissue samples, enabled diagnosis and prediction of HGSC and all tumor samples in comparison with normal tissues, with overall agreements of 96.4% and 96.2%, respectively. HGSC and BOT discrimination was achieved with an overall accuracy of 93.0%. Interestingly, our classification model allowed identification of three BOT samples presenting unusual histologic features that could be associated with the development of low-grade carcinomas. Our results suggest DESI-MS as a powerful approach for rapid serous ovarian cancer diagnosis based on altered metabolic signatures. Cancer Res; 77(11); 2903–13. ©2017 AACR.

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Tumor-Localized Secretion of Soluble PD1 Enhances Oncolytic Virotherapy

Oncolytic virotherapy represents an attractive option for the treatment of a variety of aggressive or refractory tumors. While this therapy is effective at rapidly debulking directly injected tumor masses, achieving complete eradication of established disease has proven difficult. One method to overcome this challenge is to use oncolytic viruses to induce secondary antitumor immune responses. Unfortunately, while the initial induction of these immune responses is typically robust, their subsequent efficacy is often inhibited through a variety of immunoregulatory mechanisms, including the PD1/PDL1 T-cell checkpoint pathway. To overcome this inhibition, we generated a novel recombinant myxoma virus (vPD1), which inhibits the PD1/PDL1 pathway specifically within the tumor microenvironment by secreting a soluble form of PD1 from infected cells. This virus both induced and maintained antitumor CD8+ T-cell responses within directly treated tumors and proved safer and more effective than combination therapy using unmodified myxoma and systemic αPD1 antibodies. Localized vPD1 treatment combined with systemic elimination of regulatory T cells had potent synergistic effects against metastatic disease that was already established in secondary solid organs. These results demonstrate that tumor-localized inhibition of the PD1/PDL1 pathway can significantly improve outcomes during oncolytic virotherapy. Furthermore, they establish a feasible path to translate these findings against clinically relevant disease. Cancer Res; 77(11); 2952–63. ©2017 AACR.

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Malignant Duodenal GIST in a Patient with Situs Inversus Totalis—a Rare Association and Brief Review of Literature



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Malignant Duodenal GIST in a Patient with Situs Inversus Totalis—a Rare Association and Brief Review of Literature



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Correction: Chromosome Instability Modulated by BMI1-AURKA Signaling Drives Progression in Head and Neck Cancer



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TAM Receptor Tyrosine Kinases in Cancer Drug Resistance

Receptor tyrosine kinases (RTK) are major regulators of key biological processes, including cell growth, survival, and differentiation, and were established early on as proto-oncogenes, with aberrant expression linked to tumor progression in many cancers. Therefore, RTKs have emerged as major targets for selective therapy with small-molecule inhibitors. However, despite improvements in survival rates, it is now apparent that the targeting of RTKs with selective inhibitors is only transiently effective, as the majority of patients eventually become resistant to therapy. As chemoresistance is the leading cause of cancer spread, progression, and mortality, there is an increasing need for understanding the mechanisms by which cancer cells can evade therapy-induced cell death. The TAM (Tyro3, Axl, Mer) subfamily of RTKs in particular feature in a variety of cancer types that have developed resistance to a broad range of therapeutic agents, including both targeted as well as conventional chemotherapeutics. This article reviews the roles of TAMs as tumor drivers and as mediators of chemoresistance, and the potential effectiveness of targeting them as part of therapeutic strategies to delay or combat resistance. Cancer Res; 77(11); 2775–8. ©2017 AACR.

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Multinuclear NMR and MRI Reveal an Early Metabolic Response to mTOR Inhibition in Sarcoma

Biomarkers predicting rapalog responses in sarcomas where PI3K and mTOR are often hyperactivated could improve the suitable recruitment of responsive patients to clinical trials. PI3K/mTOR pathway activation drives energy production by regulating anaerobic glycolysis in cancer cells, suggesting a route toward a monitoring strategy. In this study, we took a multimodality approach to evaluate the phenotypic effects and metabolic changes that occur with inhibition of the PI3K/mTOR pathway. Its central role in regulating glycolysis in human sarcomas was evaluated by short- and long-term rapamycin treatment in sarcoma cell lines. We observed an overall decrease in lactate production in vitro, followed by cell growth inhibition. In vivo, we observed a similar quantitative reduction in lactate production as monitored by hyperpolarized MRI, also followed by tumor size changes. This noninvasive imaging method could distinguish reduced cell proliferation from induction of cell death. Our results illustrate the use of hyperpolarized MRI as a sensitive technique to monitor drug-induced perturbation of the PI3K/mTOR pathway in sarcomas. Cancer Res; 77(11); 3113–20. ©2017 AACR.

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Expression of Neuroendocrine Factor VGF in Lung Cancer Cells Confers Resistance to EGFR Kinase Inhibitors and Triggers Epithelial-to-Mesenchymal Transition

Mutations in EGFR drive tumor growth but render tumor cells sensitive to treatment with EGFR tyrosine kinase inhibitors (TKI). Phenotypic alteration in epithelial-to-mesenchymal transition (EMT) has been linked to the TKI resistance in lung adenocarcinoma. However, the mechanism underlying this resistance remains unclear. Here we report that high expression of a neuroendocrine factor termed VGF induces the transcription factor TWIST1 to facilitate TKI resistance, EMT, and cancer dissemination in a subset of lung adenocarcinoma cells. VGF silencing resensitized EGFR-mutated lung adenocarcinoma cells to TKI. Conversely, overexpression of VGF in sensitive cells conferred resistance to TKIs and induced EMT, increasing migratory and invasive behaviors. Correlation analysis revealed a significant association of VGF expression with advanced tumor grade and poor survival in patients with lung adenocarcinoma. In a mouse xenograft model of lung adenocarcinoma, suppressing VGF expression was sufficient to attenuate tumor growth. Overall, our findings show how VGF can confer TKI resistance and trigger EMT, suggesting its potential utility as a biomarker and therapeutic target in lung adenocarcinoma. Cancer Res; 77(11); 3013–26. ©2017 AACR.

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Highlights from Recent Cancer Literature



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TAM Receptor Tyrosine Kinases in Cancer Drug Resistance

Receptor tyrosine kinases (RTK) are major regulators of key biological processes, including cell growth, survival, and differentiation, and were established early on as proto-oncogenes, with aberrant expression linked to tumor progression in many cancers. Therefore, RTKs have emerged as major targets for selective therapy with small-molecule inhibitors. However, despite improvements in survival rates, it is now apparent that the targeting of RTKs with selective inhibitors is only transiently effective, as the majority of patients eventually become resistant to therapy. As chemoresistance is the leading cause of cancer spread, progression, and mortality, there is an increasing need for understanding the mechanisms by which cancer cells can evade therapy-induced cell death. The TAM (Tyro3, Axl, Mer) subfamily of RTKs in particular feature in a variety of cancer types that have developed resistance to a broad range of therapeutic agents, including both targeted as well as conventional chemotherapeutics. This article reviews the roles of TAMs as tumor drivers and as mediators of chemoresistance, and the potential effectiveness of targeting them as part of therapeutic strategies to delay or combat resistance. Cancer Res; 77(11); 2775–8. ©2017 AACR.

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SETD1B Activates iNOS Expression in Myeloid-Derived Suppressor Cells

Inducible nitric oxide synthase (iNOS) generates nitric oxide (NO) in myeloid cells that acts as a defense mechanism to suppress invading microorganisms or neoplastic cells. In tumor-bearing mice, elevated iNOS expression is a hallmark of myeloid-derived suppressor cells (MDSC). MDSCs use NO to nitrate both the T-cell receptor and STAT1, thus inhibiting T-cell activation and the antitumor immune response. The molecular mechanisms underlying iNOS expression and regulation in tumor-induced MDSCs are unknown. We report here that deficiency in IRF8 results in diminished iNOS expression in both mature CD11b+Gr1− and immature CD11b+Gr1+ myeloid cells in vivo. Strikingly, although IRF8 was silenced in tumor-induced MDSCs, iNOS expression was significantly elevated in tumor-induced MDSCs, suggesting that the expression of iNOS is regulated by an IRF8-independent mechanism under pathologic conditions. Furthermore, tumor-induced MDSCs exhibited diminished STAT1 and NF-κB Rel protein levels, the essential inducers of iNOS in myeloid cells. Instead, tumor-induced MDSCs showed increased SETD1B expression as compared with their cellular equivalents in tumor-free mice. Chromatin immunoprecipitation revealed that H3K4me3, the target of SETD1B, was enriched at the nos2 promoter in tumor-induced MDSCs, and inhibition or silencing of SETD1B diminished iNOS expression in tumor-induced MDSCs. Our results show how tumor cells use the SETD1B–H3K4me3 epigenetic axis to bypass a normal role for IRF8 expression in activating iNOS expression in MDSCs when they are generated under pathologic conditions. Cancer Res; 77(11); 2834–43. ©2017 AACR.

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The p53/p21 Complex Regulates Cancer Cell Invasion and Apoptosis by Targeting Bcl-2 Family Proteins

The tumor suppressor p53 binds prosurvival Bcl-2 family proteins such as Bcl-w and Bcl-XL to liberate Bax, which in turn exerts proapoptotic or anti-invasive functions depending on stress context. On the basis of our previous finding that p53 interacts with p21, we investigated the possible involvement of p21 in these functions. Here, we report that although p53 can bind Bcl-w alone, it requires p21 to liberate Bax to suppress cell invasion and promote cell death. p21 bound Bcl-w, forming a p53/p21/Bcl-w complex in a manner that maintained all pairwise p53/p21, p21/Bcl-w, and p53/Bcl-w interactions. This allowed Bax liberation from the complex. Accordingly, a p53 derivative incapable of binding p21 failed to mediate radiotherapy-induced tumor cell death in mice. Bcl-XL also served as a target of the cooperative action of p53 and p21. Overall, our findings indicate that the p53/p21 complex rather than p53 itself regulates cell invasion and death by targeting Bcl-2 proteins. We propose that the p53/p21 complex is a functional unit that acts on multiple cell components, providing a new foundation for understanding the tumor-suppressing functions of p53 and p21. Cancer Res; 77(11); 3092–100. ©2017 AACR.

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Widespread Use of Misidentified Cell Line KB (HeLa): Incorrect Attribution and Its Impact Revealed through Mining the Scientific Literature

Continuous cell lines are widely used, but can result in invalid, irreproducible research data. Cell line misidentification is a common problem that can be detected by authentication testing; however, misidentified cell lines continue to be used in publications. Here we explore the impact of one misidentified cell line, KB (HeLa), on the scientific literature. We identified 574 articles between 2000 and 2014 that provided an incorrect attribution for KB, in accordance with its false identity as oral epidermoid carcinoma, but only 57 articles that provided a correct attribution for KB, as HeLa or cervical adenocarcinoma. Statistical analysis of 57 correct and 171 incorrect articles showed that the number of citations to these articles increased over time. Content analysis of 200 citing articles showed there was a tendency to describe the cell line in accordance with the description in the cited paper. Analysis of journal impact factor showed no significant difference between correct and incorrect groups. Articles using KB or citing that usage were most frequently published in the subject areas of pharmacology, pharmacy, oncology, and medicinal chemistry. These findings are important for science policy and support the need for journals to require authentication testing as a condition of publication. Cancer Res; 77(11); 2784–8. ©2017 AACR.

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Expression of Neuroendocrine Factor VGF in Lung Cancer Cells Confers Resistance to EGFR Kinase Inhibitors and Triggers Epithelial-to-Mesenchymal Transition

Mutations in EGFR drive tumor growth but render tumor cells sensitive to treatment with EGFR tyrosine kinase inhibitors (TKI). Phenotypic alteration in epithelial-to-mesenchymal transition (EMT) has been linked to the TKI resistance in lung adenocarcinoma. However, the mechanism underlying this resistance remains unclear. Here we report that high expression of a neuroendocrine factor termed VGF induces the transcription factor TWIST1 to facilitate TKI resistance, EMT, and cancer dissemination in a subset of lung adenocarcinoma cells. VGF silencing resensitized EGFR-mutated lung adenocarcinoma cells to TKI. Conversely, overexpression of VGF in sensitive cells conferred resistance to TKIs and induced EMT, increasing migratory and invasive behaviors. Correlation analysis revealed a significant association of VGF expression with advanced tumor grade and poor survival in patients with lung adenocarcinoma. In a mouse xenograft model of lung adenocarcinoma, suppressing VGF expression was sufficient to attenuate tumor growth. Overall, our findings show how VGF can confer TKI resistance and trigger EMT, suggesting its potential utility as a biomarker and therapeutic target in lung adenocarcinoma. Cancer Res; 77(11); 3013–26. ©2017 AACR.

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