miR-671-5p Inhibits Tumor Proliferation by Blocking Cell Cycle in Osteosarcoma

Osteosarcoma (OS), a highly aggressive bone tumor, mainly occurs in young patients and always presents abnormalities in molecular biology, such as microRNAs (miRNAs). However, the characteristic and underlying mechanism of miR-671-5p in OS are still unclear. In this study, we certify that miR-671-5p is remarkably downregulated in OS tissues and cells. Overexpressed miR-671-5p can suppress OS cell proliferation in vivo and in vitro, by the way of arresting cell-cycle progression. The overexpression of cyclin D1 (CCND1) and CDC34 promotes cell proliferation and cell-cycle promotion, whose functions are contrary to miR-671-5p. miR-671-5p directly binds to CCND1 and CDC34, which are thought as the key factors in regulating cell cycle. Taken together, our results suggest that by targeting CCND1 and CDC34, miR-671-5p plays a tumor suppressor in OS to inhibit the development of OS, implicating it as a novel target for therapeutic intervention in OS.