MicroRNA-613 represses prostate cancer cell proliferation and invasion through targeting Frizzled7

A growing number of studies have indicated that microRNAs (miRNAs) are critical regulators of carcinogenesis and cancer progression and may serve as potential therapeutic tools for cancer therapy. Frizzled7 (Fzd7), the most important receptor of the Wnt signaling pathway, is extensively involved in cancer development and progression. However, the role of Fzd7 in prostate cancer remains unclear. In this study, we aimed to explore the expression of Fzd7 in prostate cancer and test whether modulating Fzd7 expression by miR-613 would have an impact on prostate cancer cell proliferation and invasion. We found that Fzd7 was highly expressed in prostate cancer cell lines. Through bioinformatics analysis, Fzd7 was predicted as a target gene of miR-613, which was validated by dual-luciferase reporter assays, real-time quantitative polymerase chain reaction and Western blot analysis. By gain of function experiments, we showed that overexpression of miR-613 significantly suppressed prostate cancer cell proliferation and invasion. Furthermore, miR-613 overexpression markedly downregulated the Wnt signaling pathway. Through a rescue experiment, we showed that overexpression of Fzd7 could abrogate the inhibitory effect of miR-613 on cell proliferation and invasion as well as Wnt signaling. Additionally, these results were further strengthened by data showing that miR-613 was significantly downregulated in prostate cancer tissues, exhibiting an inverse correlation with Fzd7 expression. In conclusion, our study suggests that miR-613 functions as a tumor suppressor, partially through targeting Fzd7, and is a potential therapeutic target for prostate cancer.