Human bone marrow mesenchymal stem cells-derived microRNA-205-containing exosomes impede the progression of prostate cancer through suppression of RHPN2

Background: Human bone marrow mesenchymal stem cells (hBMSCs) are implicated in cancer initiation and metastasis, sometimes by releasing exosomes that mediate cell communication by delivering microRNAs (miRNAs). This study aimed to investigate the physiological mechanisms by which exosomal miR-205 derived from hBMSCs may modulate the growth of prostate cancer cells. Methods: Microarray-based gene expression profiling of prostate cancer was adopted to identify differentially expressed genes and regulatory miRNAs, which identified the candidates RHPN2 and miR-205 as the study focus. Then the binding affinity between miR-205 and RHPN2 was identified using in silico analysis and luciferase activity detection. Prostate cancer cells were co-cultured with exosomes derived from hBMSCs treated with either miR-205 mimic or miR-205 inhibitor. Subsequently, prostate cancer cell proliferation, invasion, migration, and apoptosis were detected in vitro. The effects of hBMSCs-miR-205 on tumor growth were investigated in vivo. Results: miR-205 was downregulated, while RHPN2 was upregulated in prostate cancer cells. RHPN2 was a target of miR-205, and upregulated miR-205 inhibited prostate cancer cell proliferation, invasion, and migration and promoted apoptosis by targeting RHPN2. Next, experiments demonstrated that hBMSCs-derived exosomes carrying miR-205 contributed to repressed prostate cancer cell proliferation, invasion, and migration and enhanced apoptosis. Furthermore, in vivo assays confirmed the inhibitory effects of hBMSCs-derived exosomal miR-205 on prostate cancer. Conclusion: The hBMSCs-derived exosomal miR-205 retards prostate cancer progression by inhibiting RHPN2, suggesting that miR-205 may present a predictor and potential therapeutic target for prostate cancer.