Abstract 97: A E2F6 ceRNA network suppresses dendritic cell function, via PBX1/IL-10 signaling, in ovarian cancer

Abstract

Abstract It is reported that long-term use of estrogen could increase the risk of ovarian cancer. However, the role of estrogen in immunoevasion is not fully explored. We have previously demonstrated that estrogen-mediated upregulation of E2F6, and, c-Kit, by epigenetic silencing of miR-193a, and a competing endogenous (ceRNA) mechanism. In this study, we found that PBX1, a transcriptional activator of the immunosuppressive cytokine, IL-10, is also a target of miR-193a. Importantly, overexpression of the E2F6 3’UTR upregulates both E2F6 and, PBX1, as well as IL10 in ovarian cancer cell lines, suggesting that ceRNA mechanism exists between E2F6 and PBX1. These phenomena are further supported by our stochastic simulation of the estrogen-mediated E2F6 ceRNA network on the distribution of E2F6 and PBX1 mRNA in cancer cells, which is consistent with the TCGA ovarian cancer RNA-Seq dataset. Importantly, monocyte-derived dendritic cell activation of T-cell function was inhibited by pretreatment of conditioned media derived from ovarian cancer cells overexpressing E2F6 3’UTR; such inhibition was rescueable by an anti-IL-10 antibody. Clinically, IL10 level was higher in ovarian cancer patients with higher E2F6 and PBX1, and in ovarian cancer cell lines overexpressed with E2F6 3’UTR. Taken together, these results showed that E2F6 could suppress anti-tumor immune response of dendritic cell, E2F6 ceRNA network. Epigenetic intervention in restoring the expression of miR-193a may be able to enhance anti-tumor immune response against ovarian cancer. Citation Format: Michael W.Y. Chan, Yin-Chen Chen, Ching-Wen Lin, Frank Cheng, Ching-Cher Sanders Yan, Chao-Ping Hsu, Yu-Min Chuang, Jie-Ting Low, Xiaojing Ma, Yao-Ting Huang, Chia-Bin Chang, Chin Li, Hung-Cheng Lai, Shu-Fen Wu, Shih-Hsun Hung, Je-Chiang Tsai. A E2F6 ceRNA network suppresses dendritic cell function, via PBX1/IL-10 signaling, in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 97.