Abstract 1381: Reprogramming of iron metabolism confers ferroptosis resistance in ECM-detached cells

Abstract

Abstract Cancer cells often acquire resistance to cell death programs induced by loss of integrin-mediated attachment to extracellular matrix (ECM). Given that adaptation to ECM-detached conditions can facilitate tumor progression and metastasis, there is significant interest in effective elimination of ECM-detached cancer cells. Ferroptosis is an iron dependent non-apoptotic cell death due to catastrophic accumulation of lipid peroxidation. While the mechanism that determines ferroptosis sensitivity has been extensively investigated in attached cells, how cells respond to ferroptosis under ECM detachment is largely unknown. Here, we find that ECM-detached cells are remarkably resistant to the induction of ferroptosis. While alterations in membrane lipid content are observed during ECM-detachment, it is instead fundamental changes in iron metabolism that underlie resistance of ECM-detached cells to ferroptosis. More specifically, our data demonstrate that levels of free iron are low during ECM-detachment due to changes in both iron uptake and iron storage. In addition, we establish that lowering the levels of iron storage proteins sensitizes ECM-detached cells to death by ferroptosis. Taken together, our data suggest that therapeutics designed to kill cancer cells by ferroptosis may be hindered by lack of efficacy towards ECM-detached cells. Citation Format: Jianping He, Abigail M. Abikoye, Brett P. McLaughlin, Ryan S. Middleton, Ryan Sheldon, Russell G. Jones, Zachary T. Schafer. Reprogramming of iron metabolism confers ferroptosis resistance in ECM-detached cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1381.