Regulation of Ferroptotic Cancer Cell Death by GPX4

Abstract

SUMMARY Ferroptosis is a form of nonapoptotic cell death for which key regulators remain unknown. We sought a common mediator for the lethality of 12 ferroptosisinducing small molecules. We used targeted metabolomic profiling to discover that depletion of glutathione causes inactivation of glutathione peroxidases (GPXs) in response to one class of compounds and a chemoproteomics strategy to discover that GPX4 is directly inhibited by a second class of compounds. GPX4 overexpression and knockdown modulated the lethality of 12 ferroptosis inducers, but not of 11 compounds with other lethal mechanisms. In addition, two representative ferroptosis inducers prevented tumor growth in xenograft mouse tumor models. Sensitivity profiling in 177 cancer cell lines revealed that diffuse large B cell lymphomas and renal cell carcinomas are particularly susceptible to GPX4-regulated ferroptosis. Thus, GPX4 is an essential regulator of ferroptotic cancer cell death.

Ferroptosis: process and function

“…4 In vivo, piperazine erastin has been shown to have better stability and water solubility than erastin to inhibit cancer growth. 6 One of the direct molecular targets of erastin is the mitochondrial voltage-dependent anion channel (VDAC) (Figure 1c). 4 Erastin can directly bind to VDAC2/3 in BJeLR cells.…”

“…3 RSL3 is a direct inhibitor of GPX4, but not system X c − . 6 After binding to GPX4, RSL3 inactivates GPX4 to induce ROS production from lipid peroxidation ( Figure 1a). 6 Thus, at least two types of RSLs exist.…”

“…6 After binding to GPX4, RSL3 inactivates GPX4 to induce ROS production from lipid peroxidation ( Figure 1a). 6 Thus, at least two types of RSLs exist. Type I RSLs such as erastin and RSL5 can target upstream regulators (e.g., VDAC and system X c − ) to induce ferroptosis.…”

“…BSO inhibits GSH synthesis with decreased GPX activity and increased ROS levels, which results in ferroptosis in Ras-mutated cells. 6 Acetaminophen. The reactive metabolite of acetaminophen has been identified as N-acetyl-p-benzoquinone imine, which causes GSH depletion and increases liver damage ( Figure 1a).…”

“…9,10 Each of these additional FINs generates ROS, whereas BHT strongly suppresses this lethal ROS-induced cell death. 6 In the LC-MS-based GPX4 assay, cells treated with any of the seven DPI family members (DPI7, DPI10, DPI12, DPI13, DPI17, DPI18, and DPI19) are unable to detect reduced PC-OOH levels, which is a specific substrate of GPX4. 6 Like RSL3, these FIN compounds (class II FINs) directly inhibit GPX4 activity without GSH depletion ( Figure 1a).…”