Hypoxia promoted renal cell carcinoma cell migration through regulating lncRNA-ENST00000574654.1.

Background: Hypoxia is common in solid tumor masses that has functional consequences for tumor progression. Previous studies demonstrated that nearly 80% renal cell carcinoma (RCC) are under hypoxia. However, effect and its mechanism of hypoxia on RCC cell invasion remains to be defined. Methods: The shRNA expression vectors, which were constructed to express a short hairpin RNA against lncRNA and overexpression of lncRNA, were transfected into the RCC cell lines (SW839 and OSRC-2). Levels of lncRNA-ENST00000574654.1, VEGF-A and VEGF-C mRNA and protein were examined by real-time quantitative-fluorescent PCR and Western blot analysis, respectively. The effects of lncRNA silencing and overexpression on cell invasion of SW839 and OSRC-2 cells were evaluated with cell migration assay. Results: Hypoxia significantly stimulated cell invasion in both RCC cell lines (SW839: 2.38 +/- 0.19 of normoxia vs 7.83 +/- 0.38 of hypoxia, P < 0.05; and OSRC-2: 1.00 +/- 0.08 of normoxia vs 5.88 +/- 0.32 of hypoxia, P < 0.05). LncRNA microarray analysis found that lncRNA-ENST00000574654.1 was down-regulated under hypoxia. Consistently, over-expression of lncRNA-ENST00000574654.1 resulted in significant blockade of hypoxia-induced RCC migration. Furthermore, expression of lncRNA-ENST00000574654.1 was regulated by HIF-1 alpha and VEGA-A through interacting with hnRNP, which in turn regulated the RCC cell invasion. Conclusions: These findings suggested that hypoxia promoted RCC cell invasion through HIF-1 alpha/lncRNA (ENST00000574654.1)/hnRNP/VEGF-A pathway. Targeting this pathway could potentially improve therapeutic outcomes of renal cell carcinoma.