Epithelial ovarian cancer (EOC) remains the fifth leading cause of cancer related death in women worldwide, partly due to the survival of chemoresistant, stem-like tumor-initiating cells (TICs) that promote disease relapse. Previous studies described the role of the NF-kB pathway in promoting TIC chemoresistance and survival through the action of key transcription factors (TFs) like RelA and RelB. These TFs serve as key master regulators of genes important for the inflammatory response, which also overlap with the regulation of targets associated with cancer promotion. We previously showed that RelA and RelB exert different effects in ovarian cancer cells, with RelB relatively more important for tumor initiation. In this study, we hypothesize that NF-kB signaling regulates the expression of several microRNAs (miRNAs) differentially through RelA and RelB to promote TIC survival and proliferation. miRNAs comprise a subset of small, noncoding RNAs that regulate gene expression and present potential therapeutic targets for clinical use. Inducible shRNA stably was expressed in OV90 EOC cells to knockdown RelA or RelB; cells were subsequently analyzed by miR-seq to identify differentially expressed miRNAs in cells grown in TIC vs adherent (adh) conditions. To validate the miR-seq findings, we performed qPCR assays of the candidate miRNAs differentially expressed in TIC or adh conditions with RelA or RelB knocked down. We confirmed the decreased expression of oncogenic miRNAs hsa-miR-105-5p and hsa-miR-452-5p, while also confirming the increased expression of tumor suppressive miRNA hsa-miR-34a-5p observed in the miR-seq using OV90 cells. Ongoing work will validate these expression changes in additional cell lines and conduct functional assays to characterize the effect of mimicking or inhibiting these miRNAs of interest. The identification of miRNAs differentially expressed in TICs under the control of RelA or RelB will provide key insights in designing treatments against them to prevent disease relapse in patients with EOC.

Citation Format: Rahul D. Kamdar, Brittney S. Harrington, Soumya Korrapati, Nathan Wong, Carrie D. House, Christina M. Annunziata. NF-κB signaling regulates miRNA expression in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5820.