Abstract 2668: Long non-cording RNA TUG1 promotes cisplatin resistance in ovarian cancer via DNA polymerase eta

Abstract

Abstract Ovarian cancer (OVCA) is the most malignant gynecologic cancer. Despite the use of surgery and platinum-based chemotherapy, the 5-year survival rate is approximately 30% at the time of diagnosis. Cisplatin inhibits DNA synthesis by cross-linking DNA and then induces cell apoptosis. However, cisplatin resistance often causes treatment failure and tumor relapse in OVCA patients. To overcome the cisplatin resistance in OVCAs, we studied the mechanism of chemoresistance by a long non-coding RNA (lncRNA), TUG1 (taurine upregulated gene 1), which is associated with carcinogenesis and drug sensitivity in OVCAs. The expression level of TUG1 in cisplatin-resistant OVCA clinical samples is significantly higher than that of cisplatin-sensitive samples by public database. A depletion of TUG1 increased the sensitivity of OVCA cells to cisplatin together with upregulation of a set of miRNAs in vitro. We examined the targets of miRNAs and found that TUG1 depletion downregulates DNA polymerase eta (Polη) by upregulating the miRNAs. Polη is a major translesion DNA synthesis (TLS) DNA polymerase, which bypasses DNA lesions produced by DNA damaging agents and helps DNA replication. The expression level of Polη showed a positive correlation with that of TUG1 in OVCA clinical samples. Overexpression of Polη recovered cisplatin resistance in TUG1-depleted cells. Finally, cisplatin treatment combined with TUG1 depletion effectively inhibited tumor growth in xenograft mouse models, indicating the efficacy of TUG1 depletion in vivo. Our data provide a strong rationale for targeting TUG1 as a novel therapeutic approach to overcome cisplatin resistance in OVCA. Citation Format: Ryosuke Sonobe. Long non-cording RNA TUG1 promotes cisplatin resistance in ovarian cancer via DNA polymerase eta [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 2668.