Abstract 3723: Identification and functional characterization of long noncoding RNAs that regulate TGF-<&946;>-Smad pathway as Smad co-factors

Abstract

Abstract TGF-β-Smad pathway participates in various biological processes such as development, differentiation, growth regulation, and cancer progression including epithelial-mesenchymal transition (EMT). Long non-coding RNAs (lncRNAs) also involved in carcinogenesis and cancer malignancies. To identify lncRNAs regulating TGF-β-Smad pathway, we comprehensively identified lncRNAs induced by TGF-β and found and reported a lncRNA ELIT-1 (EMT-associated lncRNA induced by TGF-β-1) which was induced by TGF-β and promoted EMT by facilitating TGF-β-Smad signaling. ELIT-1 bound to Smad and participated in expression of TGF-β target genes including Snail. Prognosis of lung adenocarcinoma and gastric cancer patients with high expression of ELIT-1 was poor suggesting that ELIT-1 may be useful as a novel prognostic and therapeutic target. Recently, we found that lincNMR (long intergenic noncoding RNA-nucleotide metabolism regulation) was induced via TGF-β-Smad pathway in various cell lines. Moreover, RNA-seq analysis using lincNMRs-depleted cells indicated that lincNMRs was involved in expression of APOBEC3B, a cytidine deaminase, promoting C to U mutation and highly expressed in various human cancers. Although, regulatory mechanisms of APOBEC3B expression have not been fully elucidated, we proved that lincNMRs bound to Smad and promoted the activity of APOBEC3B promoter. These data suggest that lincNMRs participate in APOBEC3B expression by collaborating with TGF-β-Smad pathway. Additionally, high expression of lincNMRs was positively correlated with high expression of APOBEC3B in various cancer cell lines. The high expression of APOBEC3B as well as lincNMR was significantly associated with their poor prognosis in liver and lung cancer patients, suggesting that lincNMR may contribute to tumor malignancy by enhanced expression of APOBEC3B via TGF-β-Smad pathway. Citation Format: Masatoshi Kitagawa, Kosuke Ota, Tatsuya Ohhata, Satoshi Sakai. Identification and functional characterization of long noncoding RNAs that regulate TGF-<&946;>-Smad pathway as Smad co-factors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3723.