Long Non-coding RNA Inhibits VEGFA Expression via Enhancing Its DNA Methylation Leading to Tumor Suppression in Renal Carcinoma.

Long non-coding RNA (lncRNA ) plays a critical role in numerous malignancies. However, the function of lncRNA in renal carcinoma (RC) remains enigmatic. The purpose of this study is to characterize the effects of lncRNA on RC progression. The expression pattern of lncRNA and the vascular endothelial growth factor A (VEGFA) in RC tissues and cells was characterized by RT-qPCR and Western blot analysis. The roles of lncRNA and VEGFA in the progression of RC were studied by gain- or loss-of-function experiments. Bioinformatics data analysis was used to predict CpG islands in the promoter region. MSP was applied to detect the level of DNA methylation in RC cells. The interaction between lncRNA and VEGFA was identified by RNA immunoprecipitation and RNA-protein pull down assays. Recruitment of DNA methyltransferases (Dnmt) to the promoter region was achieved by chromatin immunoprecipitation. The subcellular localization of lncRNA was detected by fractionation of nuclear and cytoplasmic RNA. Cell viability was investigated by CCK-8 assay, cell migration was tested by transwell migration assay, and apoptosis was analyzed by flow cytometry. The expression of epithelial-mesenchymal transition-related and apoptotic factors was evaluated by Western blot analysis. Finally, the effect of the lncRNA /VEGFA axis was confirmed in an tumor xenograft model. LncRNA was poorly expressed in RC tissues and cells with a primary localization in the nucleus, while VEGFA was highly expressed. Overexpression of lncRNA or knockdown of inhibited cell proliferation and migration and induced the apoptosis of RC cells. Bioinformatics analysis indicated the presence of CpG islands in the promoter region. Lack of methylation at specific sites in the promoter region was detected through MSP assay. We found that lncRNA was able to inhibit VEGFA expression through recruitment of Dnmt1, Dnmt3a, and Dnmt3b to the promoter region. LncRNA was also able to suppress RC tumor growth repression of VEGFA in an mouse xenograft model. Our data shows that by downregulating expression in RC, the lncRNA has tumor-suppressive potential.