MicroRNA-193a-3p inhibits cell proliferation in prostate cancer by targeting cyclin D1

MicroRNAs (miRNAs) are small non-coding RNAs that affect various biological processes by altering the expression of a target gene. An miRNA microarray analysis has previously revealed a significant decrease in miR-193a-3p levels in prostate cancer tissues compared with that in their benign prostate hyperplasia counterparts. However, the role of miR-193a-3p has yet to be elucidated. In the present study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to evaluate the expression levels of miR-193a-3p in two human prostate cancer cell lines. Forced overexpression of miR-193a-3p was established by transfecting mimics into DU-145 and PC3 cell lines. Cell proliferation and the cell cycle were assessed using a cell viability assay, flow cytometry and a colony formation assay. In addition, the target gene of miR-193a-3p was determined by a luciferase assay, RT-qPCR and western blot analysis. The regulation of the cell cycle by miR-193a-3p was also evaluated by western blotting. The results demonstrated that miR-193a-3p expression levels were lower in prostate cancer cell lines as compared with the RWPE normal prostate epithelium cell line. Subsequent gain-of-function studies revealed that stable miR-193a-3p transfection inhibited cell viability, proliferation and colony formation, and induced G₁ phase arrest in prostate cancer cells. A luciferase assay and western blot analysis identified cyclin D1 (CCND1) as a direct target gene of miR-193a-3p. In addition, the forced expression of CCND1 was able to counter the inhibitory effects of miR-193a-3p transfection in the prostate cancer cells. In summary, the results suggest that miR-193a-3p may inhibit the viability, proliferation and survival of prostate cancer cells by regulating the expression profile of CCND1, and that miR-193a-3p may be a novel therapeutic biomarker for prostate cancer.