Abstract 826: Investigating TWEAK-mediated regulation of ovarian cancer cell survival.

Abstract High-Grade Serous Ovarian Cancer (HGSOC) remains a salient concern in women’s health, with 90% of patients eventually experiencing resistance to standard-of-care chemotherapies. Research implicates a subpopulation of quiescent, multipotent cells termed Cancer Stem-like Cells (CSCs) in contributing to resistance and relapse. We previously identified Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (TWEAK), a pro-inflammatory cytokine, as highly enriched in the tumor microenvironment following chemotherapy and a critical mediator of CSCs by activating NFkB signaling to increase survival. We also found that a subpopulation of cells without CSC features were more sensitized to chemotherapy in the presence of TWEAK, suggesting a dual role for TWEAK. Canonically, TWEAK influences cell differentiation; however, this role is ill-defined in ovarian cancer. We hypothesize that TWEAK induces chemosensitivity in non-CSCs and chemoresistance in CSCs in ovarian cancer. To study this signaling in an immunocompetent mouse model recapitulating the tumor microenvironment, the murine ovarian surface epithelial cell line ID8 (p53-mutant and p53-wild type) were used. Combination IC50 of Carboplatin and Paclitaxel was studied in both cell lines for accurate drug dosing. A panel of surface markers was assessed for baseline expression by flow cytometry, including the TWEAK receptor Fn14 (27%), and CSC markers LGR5 (3.19%), GRP78 (29%), CD117 (70%), and αVβ3(0.27%). GRP78 was identified as a promising CSC marker in the p53-mutant ID8 cell line, with baseline expression of 29% increasing significantly to 53% post-chemotherapy. FACS sorting of GRP78+ enriched fractions to have high baseline expression of stem genes SOX2,OCT4, and NANOG. To assess TWEAK induction of CSC features, pre-treatment of TWEAK in GRP78 + and GRP78- factions showed an overall increase in viability after chemotherapy treatment, suggesting TWEAK treatment before chemotherapy may provide an advantage in survival. Current work is investigating GRP78+ ID8 cells using in vitro assays for spheroid formation, extreme limiting dilution, and chemoresistance in response to TWEAK stimulation. An in vivo murine relapse model will be used to test the role of TWEAK in maintaining GRP78+ cells and relapse potential. Future studies will elucidate the role of TRAF proteins in directing the downstream effects of TWEAK-Fn14 activity. Together, these investigations provide valuable insights into the mechanisms underlying chemoresistance. Citation Format: Harshada Sapre, Mikella Robinson, Carrie House. Investigating TWEAK-mediated regulation of ovarian cancer cell survival abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 826.