Long noncoding RNAs (lncRNAs) have been investigated as a new class of regulators of cellular processes, such as cell growth, apoptosis, and carcinogenesis. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has recently been identified to be involved in tumorigenesis of several cancers such as lung cancer, pancreatic cancer, and cervical cancer. However, the role of lncRNA MALAT1 in clear cell renal cell carcinoma (ccRCC) remains unclear. Expression levels of lncRNA MALAT1 in ccRCC tissues and renal cancer cell lines were evaluated by quantitative real-time PCR (qRT-PCR), and its association with overall survival of patients was analyzed by statistical analysis. Small interfering RNA (siRNA) was used to suppress MALAT1 expression in renal cancer cells. In vitro assays were conducted to further explore its role in tumor progression. The expression level of MALAT1 was higher in ccRCC tissues and renal cancer cells compared to adjacent non-tumor tissues and normal human proximal tubule epithelial cells HK-2. The ccRCC patients with higher MALAT1 expression had an advanced clinical features and a shorter overall survival time than those with lower MALAT1 expression. And multivariate analysis showed that the status of MALAT1 expression was an independent predictor of overall survival in ccRCC. Additionally, our data indicated that knockdown expression of MALAT1 decreased renal cancer cell proliferation, migration, and invasion. Our data suggested that lncRNA MALAT1 was a novel molecule involved in ccRCC progression, which provided a potential prognostic biomarker and therapeutic target.

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Quercetin and hyperoside (QH) in combination (1:1 ratio) have previously been shown to inhibit the growth of human leukemia cells. Here, we investigated the anticancer activity of the same mixture in 786-O renal cancer cells. QH decreased the generation of reactive oxygen species (ROS) by up to 2.25-fold and increased the antioxidant capacity by up to 3-fold in 786-O cells (3.8-60 μg/ml), whereas IC50 values for viability were 18.2, 18.7 and 11.8 μg/ml, respectively. QH also induced caspase-3 cleavage (2-fold) and increased PARP cleavage. Specificity protein (Sp) transcription factors are overexpressed in cancer cells and regulate genes required for cell proliferation, survival and angiogenesis. QH treatment decreased the expression of Sp1, Sp3 and Sp4 mRNA and this was accompanied by decreased protein expression. Moreover, expression of the Sp-dependent anti-apoptotic survival gene survivin was also significantly reduced, both at the mRNA and protein levels. QH decreased microRNA-27a (miR-27a) and induced the zinc finger protein ZBTB10, an Sp-repressor, suggesting that interactions between QH and the miR-27a-ZBTB10 axis play a role in Sp downregulation. This was confirmed by transfection of cells with a specific mimic for miR-27a, which partially reversed the effects of QH. These findings are consistent with previous studies on botanical anticancer agents in colon cancer cells.