MicroRNA-30a Inhibits Osteolysis By Targeting RunX2 In Giant Cell Tumor Of Bone

Background:Giant cell tumor of bone(GCTB), as a borderline tumor with potentially aggressive behavior and rich blood vessels, occurs predominantly in the metaepiphyseal regions of the long bones and spine. It accounts for approximately 6% of all primary bone tumors, is characterized by extensive bone resorption. Three differe nt cel ular components constitute GCT- namely, spindle- like stromal cel s, osteoclast multinucleated giant cel s, and monocytic round cel s. Spindle-like stromal cel s of GCT(GCTSCs) are neoplastic cell component and have stem-like properties. Moreover, it can secrete many cytokines like Runx2 to influence the osteoclast differentiation and osteolysis in GCT.Objective:It has been reported the osteoblast transcription factor 2(RunX2) was an important transcription factor in GCT. But the mechanisms associated with posttranscriptio na l regulation of RunX2 are not completely defined. In this study, we plan to utilize miRN A to explore the mechanisms associated with posttranscriptional regulation of RunX2.Methods:In this study, miR-30 a and RunX2 expressions in 20 GCTB specimens and paratumor tissues collected from patients were measured by semi-qRT-PCR, qRT-PCR and western blot analysis. Luciferase assay was performed to validate the potential target of miR-30 a. Overexpressed miR-30a(OE-30a) stromal cel s were constructed by using TALE nucleases and the effect of OE-30 a in regulating Runx2 and its down-stream target gene MMP-13 was detected. Moreover, TRAP was also used to identify the osteoclast function in this situation.Results:We verified the upregulation of Runx2 and downregulation of miR-30 a in these 20 GCTB cases and futher proved that there is a strong negative correlation between miR-30 a and Runx2. Then the results indicated that miR-30 a can regulate the expression of RunX2 by binding to its 3’-UTR. In the end, we found an inhibition of osteoclastogenesis and osteolysis induced by OE-miR-30 a cel s.Conclusion: Our findings indicate that miR-30 a negatively regulates Runx2 and further inhibits osteoclast differentiation and osteolysis formation in GCT. This may help the diagnosis and therapeutic of bone tumors or other diseases related to bone resorption.