Investigator
Magna Graecia University
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.
The Double-Edged Sword of Oleuropein in Ovarian Cancer Cells: From Antioxidant Functions to Cytotoxic Effects
Oleuropein plays a key role as a pro-oxidant as well as an antioxidant in cancer. In this study, the activity of oleuropein, in an in vitro model of ovarian (OCCs) and breast cancer cells (BCCs) was investigated. Cell viability and cell death were analyzed. Oxidative stress was measured by CM-H2DCFDA flow cytometry assay. Mitochondrial dysfunction was evaluated based on mitochondrial reactive oxygen species (ROS) and GPX4 protein levels. Further, the effects on iron metabolism were analyzed by measuring the intracellular labile iron pool (LIP). We confirmed that high doses of oleuropein show anti-proliferative and pro-apoptotic activity on HEY and MCF-7 cells. Moreover, our results indicate that low doses of oleuropein impair cell viability without affecting the mortality of cells, and also decrease the LIP and ROS levels, keeping them unchanged in MCF-7 cells. For the first time, our data show that low doses of oleuropein reduce erastin-mediated cell death. Interestingly, oleuropein decreases the levels of intracellular ROS and LIP in OCCs treated with erastin. Noteworthily, we observed an increased amount of ROS scavenging enzyme GPX4 together with a consistent reduction in mitochondrial ROS, confirming a reduction in oxidative stress in this model.
