Alpinetin targets glioma stem cells by suppressing Notch pathway

Abstract

Glioma is among the most common human malignancies with poor prognosis. Glioma stem cells (GSCs) are the culprit of glioma, suggesting that GSCs are potential therapeutic targets. Notch signaling pathway plays a pivotal role for the function of GSCs, implying that suppression of Notch pathway may be an effective strategy for GSC-targeting therapy. In this study, we found that alpinetin, a natural compound, can suppress the proliferation and invasiveness of GSCs and induce apoptosis in GSCs. Immunoblot analysis and luciferase assay revealed that Notch signaling was suppressed by alpinetin. Furthermore, restoration of Notch signaling activity rescued the effect of alpinetin on GSC's function. The anti-tumor activity of alpinetin was further confirmed in an animal model. Collectively, targeting of GSC by alpinetin is an effective strategy for glioma therapy.

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Macrophages and endothelial cells orchestrate tumor-associated angiogenesis in oral cancer via hedgehog pathway activation

Abstract

The present study aimed to evaluate the role of Hedgehog (Hh) molecule expression in association with the clinical aspects of oral squamous cell carcinoma (OSCC), as well as angiogenesis and CD163+ macrophages. Twenty-eight cases of OSCC, nine cases of tumor-free resection margins (TM), and four cases of non-neoplastic oral mucosa (NNM) were submitted to immunohistochemistry to detect proteins Sonic Hedgehog (SHH), Indian Hedgehog (IHH), GLI1, CD163, and CD105. Protein colocalization with respect to SHH/CD163, IHH/CD163, GLI1/CD163, and GLI1/CD105 was assessed by immunohistochemical double staining. In tumor parenchyma, SHH and IHH were present in the cytoplasm of neoplastic cells, while GLI1 was observed in cytoplasm and nucleus. Endothelial cells were found to express SHH, IHH, and GLI1 within CD105+ vessels, and a positive correlation between infiltrating macrophage density (IMD) and microvascular density (MVD) was observed in cases of OSCC and TM. When compared to TM and NNM, the OSCC cases demonstrated higher immunoreactivity for SHH (p = 0.01), IHH (p = 0.39), GLI1 (p = 0.03), IMD (p = 0.0002), and MVD (p = 0.0002). Our results suggest the participation of the Hh pathway in OSCC by way of autocrine and paracrine signaling, in addition to the participation of both SHH and IHH ligands. Endothelial cells were also found to exhibit positivity with respect to Hh pathway components and we surmise that these molecules may play a role in tumor angiogenesis. CD163+ macrophages were also observed to express IHH, a ligand of this pathway, in addition to being associated with tumor neovascularization.

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MicroRNA-155 promotes apoptosis in SKOV3, A2780, and primary cultured ovarian cancer cells

Abstract

MicroRNAs (miRNAs) are a large group of small non-coding RNAs that can negatively regulate gene expression at the post-transcriptional level. The deregulation of miRNAs has been associated with tumorigenesis, drug resistance, and prognosis in cancers. Deregulated miR-155 has been reported in numerous cancers; however, its function remains unclear. 4′,6-Diamidino-2-phenylindole (DAPI) staining and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) techniques were used to determine the effects of a miR-155 mimic or inhibitor on the apoptotic ratio of ovarian cancer cells induced by cisplatin. Bioinformatic predictions, the dual-luciferase reporter assay, and western blot analysis were used to detect how miR-155 regulates X-linked inhibitor of apoptosis protein (XIAP). We demonstrated that a miR-155 mimic could decrease the IC50 value of cisplatin in SKOV3 ovarian cancer cells. Subsequently, gain- and loss-of-function analyses with a miR-155 mimic and inhibitor showed that miR-155 sensitizes ovarian cancer cells to cisplatin. Furthermore, the results from the luciferase assays and western blot analysis identified XIAP as the direct target of miR-155. In addition, introducing XIAP cDNA without a three prime untranslated region (3′-UTR) rescued the miR-155 promotion of apoptosis. These results indicate that miR-155 mediates cisplatin-induced apoptosis by targeting XIAP in ovarian cancer cells and that miR-155 could be a potential therapeutic target to increase the efficiency of ovarian cancer interventions.

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DCT015, a new sorafenib derivate, inhibits tumor growth and angiogenesis in gastric cancer models

Abstract

The objective of this study is to investigate antiproliferative activities against gastric cancer and anti-angiogenesis of DCT015, a novel sorafenib derivate, and potential mechanisms. The effects of DCT015 on proliferation and apoptosis in gastric cancer cells were evaluated by cytotoxicity assays, apoptosis analysis, flow cytometry analysis, and Western blotting assays. The in vivo antitumor effects were carried out in nude mice bearing gastric cancer. On the other hand, the anti-angiogenesis effects of DCT015 were measured by human umbilical vein endothelial cell (HUVEC) proliferation, migration, tube formation, and Western blotting analysis. The results showed that DCT015 inhibited the proliferation, induced the morphological changes of apoptosis, and increased the apoptosis percentage, as well as increased the "sub-G1" population in gastric cancer cells. DCT015 also significantly decreased the tumor volumes and tumor weights in vivo by oral administration. Immunohistochemistry assay demonstrated that DCT015 inhibited tumor growth and neovascularization. In vitro studies found that DCT015 inhibited both MEK/ERK and PI3K/Akt signaling pathways by Western blotting assays. Moreover, DCT015 significantly inhibited VEGF-induced migration and tube formation in HUVECs. Western blotting analysis showed that DCT015 downregulated VEGF-induced VEGFR2 phosphorylation with the decreased phosphorylation of the downstream key proteins. Taken together, our findings highlight that DCT015 is a promising orally anticancer drug for treating gastric cancer.

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Inhibition of proliferation and induction of apoptosis in RB116 retinoblastoma cells by afatinib treatment

Abstract

The present study investigates the effect of afatinib on the growth, induction of apoptosis in RB116 cells, and reduction of carcinoma growth in the mice transplanted with RB116 cells. The results from MTT assay revealed that afatinib inhibited the growth of RB116 cells in a dose-dependent manner. Proliferation of RB116 cells was reduced to 64 % on treatment with 200 μM concentration of afatinib after 48 h. Afatinib treatment of RB116 cells at 200 μM concentration induced apoptosis and necrosis in 49.7 and 9.4 %, respectively, after 48 h. In the RB116-transplanted mice, treatment with afatinib at 10-mg/kg doses for 45 days caused a significant (p < 0.005) reduction in the tumor volume compared to the control group. The tissue lysates of the mice containing RB116 transplant showed a significant decrease in the expressions of Ki67 and p53 in the afatinib treatment group after 45 days. However, the expression of caspase-3 was increased and of Bcl-2 remained unaltered on treatment with afatinib. Measurement of the body weight of afatinib-treated animals showed no reduction during the study. Thus, afatinib can be of therapeutic value for the treatment of retinoblastoma.

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Inhibition of class I histone deacetylases 1 and 2 promotes urothelial carcinoma cell death by various mechanisms

Class I histone deacetylases HDAC1 and HDAC2 contribute to cell proliferation and are commonly upregulated in urothelial carcinoma (UC). To evaluate whether specific inhibition of these enzymes might serve as an appropriate therapy of UC siRNA-mediated knockdown and specific pharmacological inhibition of HDAC1 and HDAC2 was applied in UC cell lines (UCCs) with distinct HDAC1 and HDAC2 expression profiles. HDACs and response marker proteins were followed by western blotting and quantitative real-time PCR. Effects of class I HDAC suppression on UCCs were analyzed by viability, colony forming, and caspase-3/7 assays, flow cytometry, senescence and LDH cytotoxity assays, and immunofluorescence staining. Whereas single knockdowns of HDAC1 or HDAC2 were impeded by compensatory upregulation of the other isoenzyme, efficient double knockdown of HDAC1 and HDAC2 reduced proliferation by up to 80 % and induced apoptosis-like cell death in all UCCs. Clonogenic growth was cell line- and HDAC-dependently reduced with double knockdown of HDAC1 and HDAC2 being usually most efficient. Class I HDAC-specific inhibitors, especially the more specific HDAC1/2 inhibitors Romidepsin and Givinostat, significantly reduced proliferation of all UCCs (IC50 3.36 nM - 4.59 µM). Romidepsin and Givinostat also significantly inhibited clonogenic growth of UCCs, with minor effects on non-tumorigenic controls. Intriguingly, these compounds induced primarily S-phase disturbances and non-apoptotic cell death in UCCs. Thus, while both ways of inhibiting HDAC1/2 share mechanisms and efficaciously inhibit cell proliferation their modes of action differ substantially. Regardless, combined inhibition of HDAC1/2 appears to represent a promising strategy for UC therapy.

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Target identification in small cell lung cancer via integrated phenotypic screening and activity-based protein profiling

To overcome hurdles in identifying key kinases in small cell lung cancer (SCLC), we integrated a target-agnostic phenotypic screen of kinase inhibitors with target identification using activity-based protein profiling (ABPP) in which a desthiobiotin-ATP probe was used. We screened 21 SCLC cell lines with known c-MYC amplification status for alterations in viability using a chemical library of 235 small molecule kinase inhibitors. One screen hit compound was interrogated with ABPP, and through this approach we re-identified aurora kinase B as a critical kinase in MYC-amplified SCLC cells. We next extended the platform to a second compound that had activity in SCLC cell lines lacking c-MYC amplification and identified TANK-binding kinase 1 (TBK1), a kinase that affects cell viability, polo-like kinase-1 signaling, G2/M arrest, and apoptosis in SCLC cells lacking MYC amplification. These results demonstrate that phenotypic screening combined with activity-based protein profiling can identify key disease drivers, suggesting that this approach, which combines new chemical probes and disease cell screens, has the potential to identify other important targets in other cancer types.

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