Circ_ 0001686 Promotes Prostate Cancer Progression by Up-Regulating SMAD3/TGFBR2 via miR-411-5p

Purpose: As the mechanism of interaction between circular RNAs (circRNAs) and microRNAs (miRNAs) in regulating the de-velopment of prostate cancer (PCa) is not clear, this study focuses on investigating these effects. Materials and Methods: Sample tissues were collected from the PCa of patients, and microarray analysis of human cir-cRNAs was conducted. The expression of circ_0001686, has_miR-411-5p (miR-411-5p) were also detected by qRT-PCR. Circ_0001686 and miR-411-5p mimics were transfected into the PCa cell lines (CWR22RV1and LNCaP) and MTT, colony formation, Transwell, and scratch wound assays were used to analyze the biological behaviors of PCa cells. Si-circ_0001686 and ASO-miR-411-5p were used as negative controls, and dual-luciferase reporter assays were performed to verify the inter-actions among circ_0001686, miR-411-5p, and SMAD3/TGFBR2. The levels of SMAD3 and TGFBR2 in different treated PCa cells were measured by western blot, and in vivo experiments in a nude mouse model were carried out to strengthen the in vitro findings of miR-411-5p. Results: The expression of circ_0001686 was up-regulated, while the expression of miR-411-5p was down-regulated in PCa cells. Moreover, circ_0001686 promoted cell proliferation, migration, and invasion. Molecular mechanism exploration re-vealed that circ_0001686 could reduce miR-411-5p, affecting the downstream target genes of SMAD3 and TGFBR2. In vitro and in vivo studies verified that miR-411-5p inhibits PCa progression. Conclusions: Circ_0001686 can reduce miR-411-5p to increase the expression of SMAD3/TGFBR2, which consequently promotes the proliferation, invasion, and migration of PCa cells.