MicroRNA-211 inhibits tumor growth and invasion through directly targeting RUNX2 in osteosarcoma

Osteosarcoma is the most common primary neoplasm of the bone and mainly occurs in adolescents and young adults. Despite great progress in current treatments, approximately one-third of patients with OS will not survive for more than five years, and fewer than 50% will live more than ten years. Aberrantly expressed microRNAs contribute to the carcinogenesis and progression of human cancers, including osteosarcoma. Increasing studies suggested that microRNA-211 (miR-211) might play important roles in the development of various cancer types; however, the expression patterns, roles and its underlying mechanism of miR-211 in osteosarcoma remain largely unexplored. In this study, we demonstrated that miR-211 was significantly downregulated in osteosarcoma tissues and cell lines compared with their adjacent normal tissues and human normal osteoblastic cell line, respectively. Functional studies showed that resumption of miR-211 inhibited cell proliferation, migration and invasion in osteosarcoma. Runt-related transcription factor 2 (Runx2) was validated as a direct target gene of miR-211. In addition, RUNX2 mRNA expression was upregulated in osteosarcoma tissues and inversely correlated with miR-211 expression. Furthermore, upregulation of RUNX2 could partially rescue the antitumor effects of miR-211 in OS cells. Taken together, these findings indicated the essential roles of miR-211 in suppressing osteosarcoma progression, suggesting miR-211 as a potential therapeutic target for the treatment of osteosarcoma.