Biological function and mechanism of MALAT-1 in renal cell carcinoma proliferation and apoptosis: role of the MALAT-1-Livin protein interaction

Long noncoding RNAs (lncRNAs) have been shown to play a critical role in cancer development and progression. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) is a kidney cancer-associated onco-lncRNA involved in the progression of renal cell carcinoma (RCC). However, the pathological role of lncRNA MALAT-1 in RCC proliferation and metastasis remains poorly understood. This study was designed to investigate the biological role and mechanism of MALAT-1 in RCC proliferation and metastasis. The experiments were performed in human tissues, renal carcinoma cell lines, and nude mice. The expression of lncRNA MALAT-1, Livin mRNA, and the Livin protein was determined by quantitative real-time PCR (qRT-PCR) or a Western blot. The interaction between MALAT-1 and Livin was evaluated by RNA pull-down and RNA binding protein immunoprecipitation (RIP). Cell viability and apoptosis in RCC cell lines were detected using CCK-8 and TUNEL assays. LncRNA MALAT-1 and the Livin protein were highly expressed in RCC tissues, as well as in RCC 786-O and Caki-1 cell lines. MALAT-1 interference contributed to an increase in cell apoptosis and a reduction in the cell viability of 786-O and Caki-1 cells. The increase in apoptosis by si-MALAT-1 was reversed by overexpression of Livin. The RIP results showed that MALAT-1 promoted the expression of the Livin protein in 786-O and Caki-1 cells by enhancing the stability of the protein. Furthermore, the volume of si-MALAT-1-786-O cell xenograft was significantly suppressed. These data indicate that lncRNA MALAT-1-mediated promotion of RCC proliferation and metastasis may be due to the upregulation of the expression of Livin.