Investigation of Ascites’ Protection of Ovarian Cancer Cells Against Ferroptosis

Abstract

Peritoneal metastasis represents the dominant route of dissemination in ovarian cancer (OVCA) and is a primary determinant of patient morbidity and mortality. This process is frequently accompanied by the accumulation of malignant ascites within the peritoneal cavity; however, the role of ascites in shaping metastatic success remains poorly defined. In parallel, emerging evidence identifies ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, as a critical vulnerability in OVCA cells. How ferroptosis-sensitive tumor cells survive during peritoneal metastatic spread remains an unresolved question.In this dissertation, we test the hypothesis that ascitic fluid suppresses ferroptotic cell death and thereby promotes peritoneal metastasis in OVCA. Using OVCA cell lines, patient-derived tumor cells, and organoid cultures, we assess ferroptosis sensitivity under defined ascites exposure conditions. We combine lipidomic profiling, lipid peroxidation and iron assays, genetic and pharmacologic perturbations, and intraperitoneal mouse models to define the mechanistic basis and in vivo relevance of ascites-mediated ferroptosis protection. We show that ascites protects OVCA cells and patient-derived models from ferroptotic cell death and enhances peritoneal tumor growth in vivo. Mechanistically, ascites downregulates the mitochondrial enzyme 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), promoting lipid droplet accumulation and lipid remodeling. Upon ferroptosis induction, ascites suppresses the upregulation of the transferrin receptor TFRC, thereby limiting labile iron accumulation and attenuating lipid peroxidation. Pharmacologic activation of lipid catabolism with fibrates reverses ascites-induced remodeling, restores ferroptosis sensitivity, and reduces peritoneal tumor dissemination in mouse models. Together, these findings establish ascites as an active metabolic regulator that suppresses ferroptosis and enables peritoneal metastatic growth in ovarian cancer, and they identify targeting ascites-driven metabolic reprogramming as a strategy to limit ovarian cancer metastasis.