MicroRNA-200b Targets DNMT3A And DNMT3B To Modulate MEG3 Expression In Renal Cell Carcinoma

Objective: MEG3 has been demonstrated to exhibit tumor suppressive activity in several cancer types, however, the expression, biological functions and its regulation mechanism are still elusive in renal cell carcinoma. We aim to investigate the expression and specific functions of MEG3 and miR-200 b in renal cancer, and try to elucidate the key role and molecular mechanism of miR-200 b in regulating the expression of MEG3.Method: The expression levels of MEG3 and miR-200 b in renal cancer tissues and cell lines were determined by microarray, bioinformatics methods and q RT-PCR. Methylation specific PCR, Mass ARRAY and 5-Aza-d C treatment were utilized to identify the change in methylation status of MEG3. Besides, MTS, colony formation assay, Ed U incorporation assay and Transwell assay were performed to detect the biological functions of MEG3 and miR-200 b in vitro. We also performed dualluciferase reporter assay and western blot to validate the direct targets of miR-200 b, and explored if the target genes could regulate the expression of MEG3.Results: The expression levels of MEG3 and miR-200 b were significantly downregulated in renal cancer tissues and cell lines, and positive correlation of MEG3 and miR-200 b was further confirmed. We also identified significant hypermethylation of MEG3 promoter. In vitro functional experiments showed that both MEG3 and miR-200 b could suppress the proliferation, migration and invasion ability. In addition, we found that DNMT3 A and DNMT3 B are direct targets of miR-200 b, and miR-200 b can regulate the expression of MEG3 through DNA methylation mechanism.Conclusion: Both MEG3 and miR-200 b are down-regulated and tumor suppressive in renal cancer, the suppression of miR-200 b may contribute to down-regulation of MEG3 in renal cancer by targeting DNMT3 A and DNMT3 B.