Abstract 136: hsa-miR-20a promotes tumorigenesis in ccRCC cancer cell lines

Abstract

Abstract Objective & Background: We have previously reported specific microRNA profiles in renal cell cancer (RCC) cell lines in vitro (Kurisetty et al. AACR Annual Meeting 2010. A # 3045;). Among the miR signatures identified, miR-20a, a member of 17-92 Oncomir cluster, stood out as a highly upregulated miR in most RCC cell lines, regardless of their VHL status. The objectives of this study are to characterize the biological significance of miR 20A upregulation in RCC. Methods: ccRCC cell lines 786.O, ACHN and KV6 and HREC, were used for cell based biological/phenotypic assays. miRNA-gene target prediction analysis was performed using miRGEN and DIANA lab programs. miR-20a-Mimic (Mi) and miR-20a-Inhibitor (In) were transiently transfected into normal HREC cell line and RCC cell lines, respectively. Cell adhesion, proliferation, softagar colony formation and transwell invasion/migration assays were performed to investigate the influences of miR-20a-Mi/In transfected into normal and ccRCC cell lines. Conditioned medium from transfected cell lines was tested for its ability to induce in vitro angiogenesis in HUVECs. Western blotting was performed to identify the changes in E2F5 protein expression in the miR-20a-Mi/In transfected normal and ccRCC cell lines. Results: In normal HREC cells, upregulation of miR 20a (by miR-20a-Mi), significantly induced cell proliferation, adhesion, migration & invasion and soft agar colony formation. miR-20a knock down in RCC cells (by miR-20a-In) significantly reduced cell proliferation, adhesion, migration & invasion and colony formation to levels similar to non-malignant HREC cells. Prediction analyses through bioinformatics approaches identified E2F5, a transcription factor and a tumor suppressor of the E2F family of transcription factors, as a target of miR-20a. Compared to non-tumor HREC cells, E2F5 was significantly downregulated in RCC cell lines, and miR-20a inhibition enhanced E2F5 expression in cancer cells. miR-20a-Mi enhanced the ability of HREC conditioned medium to induce capillary formation in HUVECs. Conclusion: Our results suggest that miR-20a may promote the tumorigenic properties of RCC in vitro. Moreover, miR 20a may promote angiogenesis. We demonstrated that E2F5 is a target of miR 20a, is reduced in RCC cell lines, and its expression is enhanced by mir-20a inhibition, suggesting that E2F5 may mediate the tumor promoting effects of miR 20a. Molecular mechanisms of miR-20a function are currently being investigated further to understand its tumorigenic potential. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 136. doi:10.1158/1538-7445.AM2011-136