MicroRNA‑195‑5p is associated with cell proliferation, migration and invasion in prostate cancer and targets MIB1.

Mind bomb 1 (MIB1) is a well‑known E3 ubiquitin ligase. MicroRNAs (miRNAs/miRs) have been found to serve important functions in cancer cell physiology. However, the clinical significance and biological function of MIB1 and miRNAs in prostate cancer (PCa) are yet to be fully elucidated. The current study predicted the interaction between MIB1 and miR‑195‑5p using TargetScan, and the results were confirmed by performing a dual‑luciferase reporter assay. The mRNA expression level of MIB1 and miR‑195‑5p in PCa and adjacent normal tissues, and PCa cell lines was detected using reverse transcription‑quantitative PCR. Cell Counting Kit‑8 and Transwell assays were used to measure the proliferation, and migration and invasion of VCaP and DU145 PCa cell lines, respectively, while western blot analysis was used to detect the protein expression level of MIB1. The results revealed that the mRNA expression level of MIB1 was increased, while the mRNA expression level of miR‑195‑5p was decreased in PCa tissues (P<0.001 and P<0.01, respectively) and in various cell lines, including PC‑3 (P<0.001 and P<0.05, respectively), VCaP (P<0.001 and P<0.01, respectively), 22Rv1 (P<0.001 and P<0.05, respectively), DU145 (P<0.001 and P<0.01, respectively) and LNCaP (P<0.001 and P<0.05, respectively). miR‑195‑5p mimics rescued the inhibitory effects caused by knockdown of MIB1 on cell proliferation, migration and invasion in the VCaP and DU145 cell lines. In addition, MIB1 overexpression restored the miR‑195‑5p overexpression‑induced repression of cell proliferation and invasion. The current study revealed that the MIB1 gene was an effector of cell proliferation, migration and invasion in PCa cell lines. Furthermore, miR‑195‑5p may regulate PCa cell proliferation and invasion by regulating MIB1, indicating its potential therapeutic application for PCa in the future.