Abstract 3549: Elevated miR-141-3p inhibits renal cell carcinoma aggressiveness by targeting epithelial-to-mesenchymal transition pathway

Abstract

Abstract Objective: Clear cell renal cell carcinoma (ccRCC), a common histological subtype of renal cell carcinoma (RCC) are categorized by their aggressive nature and comprise 90% of metastatic RCCs. Despite recent advances, management of the disease in the advanced metastatic phase is a significant challenge. Expression of miR-141-3p (miR-141) is low and function as tumor suppressor in various cancers. However, its association with long non-coding RNAs (lncRNAs) in RCC is not well understood. This study shows that miR-141 interacts with lncRNAs, and plays vital role in the regulation of stemness and epithelial-to-mesenchymal transition (EMT) in RCC. Experimental Design: Human renal cancer cell lines (ACHN and Caki-1), normal renal epithelial cells, RPTEC and tumor tissues were used for this study. We analyzed the expression of miR-141 in tissue samples and cell lines, and studied the function of miR-141 in kidney cancer progression using in vitro and in vivo models. Statistical analysis was performed to determine the clinical significance of miR-141 in kidney cancer patients. Results: Reduced expression of miR-141 was observed in ccRCC clinical specimens and cell lines. To elucidate the epigenetic role of miR-141 silencing in RCC, methylation status of CpG islands in its putative promoter region was analyzed. Result showed significant increase in miR-141 expression after 5-Aza-CdR treatment indicating that promoter hypermethylation is responsible for its inactivation. Ectopic expression of miR-141 reduced cell proliferation, clonogenicity, migration, invasion and induced apoptosis and cell cycle arrest compared to controls. An increase in cleaved PARP, cleaved caspase-3 and epithelial marker (CLDN1) was observed with a concomitant decrease in stemness (KLF4, Nanog) and EMT markers (FN1, VIM). We further investigated the biological significance of miR-141 in RCC. Loss of miR-141 function in RPTEC cells induced pro-cancerous characteristics. In addition, we examined lncRNAs (CDKN2B-As1, PCAT1 and PVT1) that bind to miR-141 and are overexpressed in RCC clinical samples compared to controls. Reduced expression of these lncRNAs was observed in RCC cells with overexpression of miR-141, supporting the notion that miR-141 interacts with these lncRNAs in RCC. Finally, in vivo experiment in nude mice revealed that intra-tumoral administration of miR-141 in the established tumors significantly suppressed tumor growth compared to controls. Furthermore, statistical analysis of patient samples showed that miR-141 may serve as a RCC diagnostic biomarker. Conclusion: Our results demonstrate that miR-141 overexpression inhibits RCC progression and inhibits epithelial-to-mesenchymal transition. These studies also show that miR-141 may be a useful RCC biomarker for early detection and monitoring RCC progression. Citation Format: Pritha Dasgupta, Priyanka Kulkarni, Shahana Majid, Varahram Shahryari, Nadeem S. Bhat, Yutaka Hashimoto, Marisa Shiina, Guoren Deng, Sharanjot Saini, Soichiro Yamamura, Yuichiro Tanaka, Rajvir Dahiya. Elevated miR-141-3p inhibits renal cell carcinoma aggressiveness by targeting epithelial-to-mesenchymal transition pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3549.