Ferroptosis Induction is Insufficient to Ensure NK Cell Activation in High-Grade Ovarian Cancer

Background: High-grade ovarian cancer (HGOC) is a heterogeneous and aggressive malignancy with a tumor microenvironment (TME) that suppresses immune responses, limiting immunotherapy efficacy. Ferroptosis, an iron-dependent form of regulated cell death, has emerged as a potential therapeutic target. Methods: We investigated the immunomodulatory effects of the ferroptosis inducer RAS-Selective Lethal 3 (RSL3) in four HGOC cell lines (ES-2, OVCAR-5, HEY, PEO-1) using flow cytometry and lactate dehydrogenase (LDH) release assays. Results: RSL3 modulated Natural Killer (NK) ligand expression in a cell line-dependent manner, resulting in differential susceptibility to NK cell-mediated cytotoxicity. OVCAR-5 cells became more susceptible to NK cell killing after treatment, whereas HEY cells showed reduced susceptibility, and ES-2 and PEO-1 cells exhibited minimal changes. Conclusions: Ferroptosis induction alone does not consistently enhance NK cell-mediated cytotoxicity in HGOC cells. These findings underscore the heterogeneity of tumor responses and highlight the need for further studies, particularly in in vivo models, to elucidate mechanisms linking ferroptosis to immune recognition and thereby inform therapeutic development.