Background: Previous research had shown that an imbalance in cell proliferation and apoptosis is a vital mechanism for tumorigenesis and cancer progression that may directly influence biological behaviors of cancer. microRNAs are associated with the occurrence and development of tumors. This study aimed to explore the influence of miR-937 on breast cancer regulation of APAF1 expression. Methods: Cancer Genome Altas microarray analysis (fold change > 2, p<0.05) was used to verify differentially expressed microRNAs and RT-qPCR was used to detect miR-937 mRNA level in breast cancer. Cell viability and proliferation were measured using CCK8 and colony formation assays, respectively, after the miR-937 mimics/inhibitors and their negative control were transfected into MCF7 cells. The variations in cell cycle and apoptosis were examined using flow cytometry. DAVID database was used to perform GO enrichment analysis. We use dual luciferase report system to detect the effect of miR-937 on the transcriptional activity of APAF1. APAF1 protein level was determined by Western blot assay. Results: miR-937 was up-regulated in breast cancer cell lines and high miR-937 expression is associated with a poorer survival rate in cancer patients. miR-937 overexpression promoted the viability, down-regulated the G1 phase ratios and increased the ability of colony formation in breast cancer cells. miR-937 inhibition inhibited the viability and the ability of colony formation, promoted the apoptosis and up-regulated the G1 phase ratios. Our results showed that miR-937 targeted bind to the APAF1-3'UTR. APAF1 overexpression inhibited the viability and the ability of colony formation, promoted the apoptosis and up-regulated the G1 phase ratios. After cells were co-transfection miR-937 mimics and APAF1, cell apoptosis level was increased. Conclusion: APAF1 up-regulation or APAF1 down-regulation in breast cancer may regulate cell proliferation and apoptosis.
Keywords: APAF1; apoptosis; breast cancer; cell proliferation; miR-937.