LncRNA UCA1 promotes renal cell carcinoma proliferation through epigenetically repressing p21 expression and negatively regulating miR-495

Long non-coding RNAs have recently emerged as important regulators in the pathogenesis and progression of cancers. The long non-coding RNA urothelial carcinoma-associated 1 is reportedly upregulated and functions as an oncogene in some tumors. However, the role of urothelial carcinoma-associated 1 in renal cell carcinoma is not well elucidated so far. In this study, we found that urothelial carcinoma-associated 1 was overexpressed in renal cell carcinoma tissues compared with the adjacent normal tissues, and higher urothelial carcinoma-associated 1 expression levels were positively associated with advanced tumor stage and poor survival time in renal cell carcinoma patients. Further studies showed that knockdown of urothelial carcinoma-associated 1 suppressed renal cell carcinoma cell proliferation and S-phase cell number in vitro. Moreover, urothelial carcinoma-associated 1 was found to be associated with enhancer of zeste homolog 2, which suppressed p21 expression through histone methylation (H3K27me3) on p21 promoter. We also showed that knockdown of urothelial carcinoma-associated 1 increased the p21 protein expression through regulating enhancer of zeste homolog 2. In addition, bioinformatics analysis and dual-luciferase reporter assays confirmed that miR-495 was a target of urothelial carcinoma-associated 1 in renal cell carcinoma, and urothelial carcinoma-associated 1 promoted cell proliferation by negatively regulating miR-495. These findings illuminated that urothelial carcinoma-associated 1 promoted renal cell carcinoma progression through enhancer of zeste homolog 2 and interacted with miR-495. Overall, overexpression of urothelial carcinoma-associated 1 functions as an oncogene in renal cell carcinoma that may offer a novel therapeutic target for renal cell carcinoma patients.