The aberrant expression of cyclin-dependent kinase-4 (CDK4) has previously been observed in human brain glioma. Furthermore, it is observed that up-regulation of CDK4 is associated with therapy resistance and relapse. However, the mechanisms behind these phenomena remain unclear. Here, we demonstrated that elevated CDK4 expression is correlated with poor prognosis in glioma after radiotherapy and that CDK4 knockdown conferred radiosensitivity in glioma cell lines. CDK4 was identified as potential downstream target of miR-124 through bioinformatics analysis and dual-firefly luciferase reporter assay. Furthermore, restoration of miR-124 could confer radiosensitivity. Cell differentiation agent-2 (CDA-2) mimicked the effect of miR-124 restoration and CDK4 knockdown, and sensitized xenografts to radiation in an animal model. Our findings demonstrated for the first time that CDK4 was a downstream target of miR-124 and that CDA-2 could radiosensitize Glioblastoma multiforme cells through the MiR-124-CDK4 axis.

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Introduction: Mitochondrial fission regulator 2 (MTFR2) belongs to the MTFR family, and 2 isoforms of MTFR2 are produced by alternative splicing. The role of MTFR2 in breast cancer (BC) remains unknown.Results: MTFR2 was upregulated in BC tissues and was strongly associated with tumor characteristics. Moreover, Kaplan-Meier and Cox proportional hazards analyses indicated that high MTFR2 expression was related to poor overall survival. In addition, the capacity for migration and invasion decreased in two BC cell lines after knockdown of MTFR2. The epithelial-mesenchymal transition pathway was inhibited in MTFR2-silenced cells. MTFR2 can switch glucose metabolism from OXPHS to glycolysis in a HIF1α- and HIF2α-dependent manner.Conclusion: Taken together, our results indicate that increased expression of MTFR2 is associated with tumour progression in breast cancer cells through switching glucose metabolism from OXPHS to glycolysis in a HIF1α- and HIF2α-dependent manner.Materials and methods: We obtained data from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) to analyse MTFR2 expression in BC. The prognostic value of MTFR2 expression was assessed using the Kaplan-Meier method. The biological influence of MTFR2 on BC cell lines was studied using proliferation, Transwell migration, invasion and mitochondrial function assays.

We investigated the potential efficacy of the Chinese herbal extract triptolide for the treatment of human breast cancer by measuring the triptolide-induced cytotoxicity in cultures of human primary breast cancer cells (BCCs) and breast cancer stem cells (BCSCs) in vitro and in vivo. Human BCCs and BCSCs from invasive ductal carcinoma samples were cultured and treated with 0.1, 0.5 or 1.0 µM triptolide. Cell death and apoptosis were measured after 24, 48 and 72 h of treatment. Mammospheres were found to be highly tumorigenic when implanted subcutaneously in nude BALB/c mice. Triptolide was cytotoxic against both human primary BCCs and BCSCs in vitro (P<0.05), but the cytotoxicity was stronger against the BCCs. In response to 1 µM triptolide for 72 h, the apoptotic rates were approximately 60% for BCCs and 30% for BCSCs. The BCSCs exhibited a high formation rate of tumors when implanted subcutaneously in nude BALB/c mice. Triptolide treatment in vivo significantly inhibited tumor growth compared with mock treatment. In conclusion, the cytotoxicity of triptolide against BCCs and BCSCs in vitro and in vivo suggests that this natural diterpenoid triepoxide compound may have clinical applications for the suppression of breast tumor growth.

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) in human immune system. DC-based tumor vaccine has met with some success in specific malignancies, inclusive of breast cancer. In this study, we electrofused MDA-MB-231 breast cancer cell line with day-3 DCs derived from peripheral blood monocytes, and explored the biological characteristics of fusion vaccine and its anti-tumor effects in vitro. Day-3 mature DCs were generated from day-2 immature DCs by adding cocktails composed of TNF-α, IL-1β, IL-6 and PEG2. Day-3 mature DCs were identified and electofused with breast cancer cells to generate fusion vaccine. Phenotype of fusion cells were identified by fluorescence microscope and flow cytometer. The fusion vaccine was evaluated for T cell proliferation, secretion of IL-12 and IFN-γ, and induction of tumor-specific CTL response. Despite differences in morphology, day-3 and day-7 DC expressed similar surface markers. The secretion of IL-12 and IFN-γ in fusion vaccine group was much higher than that in the control group. Compared with control group, DC-tumor fusion vaccine could better stimulate the proliferation of allogeneic T lymphocytes and kill more breast cancer cells (MDA-MB-231) in vitro. Day-3 DCs had the same function as the day-7 DCs, but with a shorter culture period. Our findings suggested that day-3 DCs fused with whole apoptotic breast cancer cells could elicit effective specific antitumor T cell responses in vitro and may be developed into a prospective candidate for adoptivet immunotherapy.