Targeting proprotein convertases in furin-rich lung cancer cells results in decreased in vitro and in vivo growth

ABSTRACT

Proprotein convertases (PCs) are serine proteases with an active role in the post-translational processing of numerous inactive proteins to active proteins including many substrates of paramount importance in cancer development and progression. Furin (PCSKC3), a well-studied member of this family, is overexpressed in numerous human and experimental malignancies. In the present communication we treated two furin-overexpressing non-small cell carcinoma (NSCLC) cell lines (Calu-6 andHOP-62) with the PC inhibitor CMK (Decanoyl-Arg-Val-Lys-Arg-chloromethylketone). This resulted in a diminished IGF-1R processing and a simultaneous decrease in cell proliferation of two NSCLC lines. Similarly, growth and proliferation of subcutaneous xenografts of both cell lines, were partially inhibited by an in vivo treatment with the same drug. These observations point to a potential role of PC inhibitors in cancer therapy. This article is protected by copyright. All rights reserved

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Protective effect of metformin in an aberrant crypt foci model induced by 1,2-dimethylhydrazine: Modulation of oxidative stress and inflammatory process

Abstract

Colorectal Cancer (CRC) is the third most frequent type of cancer worldwide. In the past few years, studies have revealed a protective effect of metformin (MET - an anti-hyperglycemic drug, used to treat type 2 diabetes), against CRC. The protective effect of MET has been associated with AMPK activation (and mTOR inhibition), resulting in suppressed protein synthesis, and reduced cell proliferation in malignant transformed cells. To elucidate new mechanisms for the protective effect of metformin, we evaluated the oxidative stress and inflammatory process modulation, since these processes are strictly involved in colorectal carcinogenesis. The present study evaluated the protective effect of MET in a CRC model induced by 1,2-dimethylhydrazine (DMH) in Balb/c female mice. The simultaneous/continuous treatment (administration of MET and DMH simultaneously), revealed protective activity of MET, preventing the formation of aberrant crypt foci (ACF) in 71.4% at distal colon sections, and was able to restore basal labeling of apoptosis. Treatment with MET also reduced the inflammatory process induced by DMH, resulting in of the reduction of oxidative stress and nitric oxide related parameters. This article is protected by copyright. All rights reserved

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Alternative lengthening of telomeres does exist in various canine sarcomas

Abstract

Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism (TMM) found in some human tumors such as sarcomas. Canine tumors are not characterized for ALT and the study aim was to identify if the ALT phenotype exists in canine sarcomas. Sixty-four canine sarcoma samples (20 snap-frozen, 44 FFPE) as well as six canine sarcoma cell lines were screened for ALT by C-circle assay. ALT was further evaluated by measuring telomere length via qPCR and telomere restriction-fragments including pulsed-field electrophoresis. ALT-associated proteins were validated by immunohistochemistry. Further, telomerase activity (TA) and gene expression were analyzed by TRAP and qPCR. DNA from 20 human neuroblastomas and 8 sarcoma cell lines served as comparative controls. ALT was detected in 9.4% (6/64) canine sarcomas including aggressive subtypes as hemangiosarcoma, osteosarcoma and histiocytic sarcoma. C-circle levels were comparable with human ALT-positive controls. All ALT tumors demonstrated loss of ATRX expression and 5/6 showed strong p53 expression. TA was detected in 93% (14/15) snap-frozen samples including a sarcoma with ALT activity. This tumor showed long heterogeneous telomeres, and a high level of colocalization of DAXX with telomeres. One sarcoma was ALT and TA negative. All canine and human sarcoma cell lines were ALT negative. In this study we demonstrated that canine sarcomas use ALT. As in humans, ALT was identified in aggressive sarcomas subtypes and coexisted with TA in one tumor. Overall, canine sarcomas seem to share many similarities with their human counterparts and appear an attractive model for comparative telomere research. This article is protected by copyright. All rights reserved

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The Effect of Zinc Supplementation on Insulin Resistance in Obese Subjects: a Systematic Review

Abstract

Obesity is a chronic disease characterized by excessive accumulation of body fat and the presence of metabolic disorders such as insulin resistance. In this sense, zinc is an important nutrient that stimulates insulin secretion and increases sensitivity to insulin. The aim of this study was to investigate the effect of zinc supplementation on insulin resistance in obese subjects through a systematic review of the available clinical trials. The search for articles was conducted using the PubMed, SciVerse Scopus, SciVerse ScienceDirect, and Cochrane databases, on May 25, 2016, by two authors independently. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed in the conduct of this review. The Cochrane Collaboration tool was used to assess the risk of bias of the trials included in this review. After screening of the articles, six clinical trials were included in this systematic review. The scientific evidence presented in this systematic review shows that zinc supplementation improves insulin resistance in obese individuals of both sexes.

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Association of axitinib plasma exposure and genetic polymorphisms of ABC transporters with axitinib-induced toxicities in patients with renal cell carcinoma

Abstract

Purpose

Axitinib is a selective tyrosine kinase inhibitor of VEGF receptors, approved for advanced renal cell carcinoma (RCC). Associations between axitinib plasma exposure, genetic polymorphisms of ABC transporters and axitinib-induced toxicities have not been adequately explored.

Methods

Twenty RCC patients treated with axitinib were enrolled in this study. Blood samples were collected 0, 0.5, 1, 2, 4, and 6 h after administration of axitinib on day 1 and at steady state. Plasma concentrations of axitinib were analyzed by UPLC–MS/MS. The ABCG2 (421C>A) and ABCB1 (1236C>T, 2677G>T/A, 3435C>T) genetic polymorphisms were determined by real-time PCR.

Results

ABCB1 haplotype was associated with increased dose-adjusted area under the plasma concentration–time curve (AUC) of axitinib at steady state. The incidence of fatigue during therapy was associated with high AUC_0–6 of axitinib (P = 0.013). The treatment period without discontinuation or dose reduction due to adverse events in patients with high AUC_0–6 of axitinib was significantly shorter than for those with low AUC_0–6 (P = 0.024). No significant differences were found in the frequency of adverse events among the ABCG2 genotype and ABCB1 haplotype groups.

Conclusions

Our results have demonstrated that adverse events leading to discontinuation or dose reduction in axitinib were associated with increased axitinib plasma exposure, but not directly with genetic polymorphisms of ABC transporters. Therefore, measurement of steady state axitinib plasma concentrations may be useful in avoiding adverse events in axitinib therapy.

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Ionotropic glutamate receptor antagonists and cancer therapy: time to think out of the box?

Abstract

Glutamate has a trophic function in the development of the central nervous system, regulating the proliferation and migration of neuronal progenitors. The resemblance between neuronal embryonic and tumor cells has paved the way for the investigation of the effects of glutamate on tumor cells. Indeed, tumor cells derived from neuronal tissue express ionotropic glutamate receptor (iGluRs) subunits and iGluR antagonists decrease cell proliferation. Likewise, iGluRs subunits are expressed in several peripheral cancer cells and blockade of the N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) ionotropic glutamate receptor subtypes decreases their proliferation and migration. Although these mechanisms are still being investigated, the inhibition of the mitogen-activated protein kinase pathway was shown to play a key role in the antiproliferative activity of iGluR antagonists. Importantly, MK-801, a NMDAR channel blocker, was effective and well tolerated in animal models of melanoma, lung, and breast cancers, suggesting that the blockade of iGluR signaling may represent a new strategy for cancer treatment. In this review, we focus on the significance of NMDA and AMPA receptor expression in tumor cells, as well as possible therapeutic strategies targeting these receptors.

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A pilot study of concurrent chemoradiotherapy with gemcitabine and cisplatin in patients with locally advanced biliary tract cancer

Abstract

Purpose

Combination chemotherapy with gemcitabine and cisplatin is a standard treatment for patients with advanced biliary tract cancer. This study aimed to evaluate the efficacy and safety of gemcitabine- and cisplatin-based concurrent chemoradiotherapy in patients with unresectable biliary tract cancer.

Methods

Patients with pathologically proven, unresectable, non-metastatic biliary tract cancer were enrolled. Gemcitabine was administered intravenously at a dose of 1000 mg/m² on days 1, 8, and 15. Cisplatin was administered intravenously at a dose of 70 mg/m² on day 1. All the patients underwent concurrent radiotherapy with 45 Gy in 1.8-Gy daily fractions. After treatment completion, tumor response was evaluated by using computed tomography.

Results

Eighteen patients were enrolled between June 2007 and October 2011. Their median age was 61 years (range, 38–72 years). Eight patients (44.5 %) were diagnosed with gallbladder cancer, six (33.3 %) with Klatskin's tumor, and four (22.2 %) with distal common bile duct cancer. After treatment completion, partial response was achieved in five patients (27.8 %) and stable disease in 13 patients (72.2 %). The overall response rate was 27.8 %, and the disease stabilization rate was 100 %. No grade 4 adverse events or treatment-related deaths occurred. The most common grade 3 adverse events were thrombocytopenia (33.3 %) and anemia (11.1 %). The median progression-free and overall survival times were 6.8 months (range, 4.5–19.8 months) and 9.6 months (5.4–30.4 months), respectively.

Conclusions

This study shows that gemcitabine- and cisplatin-based concurrent chemoradiotherapy is feasible and tolerable in patients with unresectable and non-metastatic biliary tract cancer.

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