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Global Survey of Cell Death Mechanisms Reveals Metabolic Regulation of Ferroptosis

View Article: PubMed Central - PubMed

ABSTRACT

Apoptosis is known as programmed cell death. Some non-apoptotic cell death is increasingly recognized as genetically controlled, or ‘regulated’. However, the full extent and diversity of these alternative cell death mechanisms remains uncharted. Here, we surveyed the landscape of pharmacologically-accessible cell death mechanisms. Of 56 caspase-independent lethal compounds, modulatory profiling revealed ten inducing three types of regulated non-apoptotic cell death. Lead optimization of one of the ten resulted in the discovery of FIN56, a specific inducer of ferroptosis. Ferroptosis occurs when the lipid repair enzyme GPX4 is inhibited. We found that FIN56 promotes degradation of GPX4. We performed chemoproteomics to reveal that FIN56 also binds to and activates squalene synthase, an enzyme involved in the cholesterol synthesis, in a manner independent of GPX4 degradation. These discoveries reveal that dysregulation of lipid metabolism is associated with ferroptosis. This systematic approach is a means to discover and characterize novel cell death phenotypes.

No MeSH data available.


Related in: MedlinePlus

ACC inhibitor prevents GPX4 protein degradationa. Effects of the mevalonate pathway modulators and ACC inhibitor on GPX4 abundance with or without FIN56. The corresponding gel is shown in Supplementary Fig. 12. b. Lipid peroxide levels upon TOFA or αToc treatments. c. Effects of TOFA and αToc on FIN56 lethality. d. Model of FIN56’s mechanism of action. Dotted arrows indicate the mechanistic details are still elusive. Statistical significance (paired two-tailed t-test) – *: p < 0.05, ††: p < 0.001, n.s.: not significant. Supplementary Fig. 11d also supports that the mevalonate pathway modulators did not change GPX4 abundance. a–c were performed in biological triplicates. mean and s.e.m. are shown in a; single representative results were shown in b and c. error-bars are s.e.m. of technical triplicates in c.
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Figure 6: ACC inhibitor prevents GPX4 protein degradationa. Effects of the mevalonate pathway modulators and ACC inhibitor on GPX4 abundance with or without FIN56. The corresponding gel is shown in Supplementary Fig. 12. b. Lipid peroxide levels upon TOFA or αToc treatments. c. Effects of TOFA and αToc on FIN56 lethality. d. Model of FIN56’s mechanism of action. Dotted arrows indicate the mechanistic details are still elusive. Statistical significance (paired two-tailed t-test) – *: p < 0.05, ††: p < 0.001, n.s.: not significant. Supplementary Fig. 11d also supports that the mevalonate pathway modulators did not change GPX4 abundance. a–c were performed in biological triplicates. mean and s.e.m. are shown in a; single representative results were shown in b and c. error-bars are s.e.m. of technical triplicates in c.

Mentions: Modulators of the mevalonate pathway, such as idebenone, are potent suppressors of ferroptosis, particularly of direct and indirect GPX4 inhibitors (FIN56 and (1S,3R)-RSL3) (Fig. 5h); however, these compounds did not block the decrease of GPX4 protein upon FIN56 treatment or induce its overexpression (Fig. 6a, Supplementary Fig. 12), indicating there may be an additional pathway that regulates GPX4 protein level in response to FIN56 treatment. We discovered that 5-(tetradecyloxy)-2-furoic Acid (TOFA), an inhibitor of acetyl-CoA carboxylase (ACC), inhibited the loss of GPX4. TOFA was also found to be a potent suppressor of FIN56 and suppressed lipid ROS generation upon FIN56 treatment (Fig. 6b,c). ACC is an enzyme involved in fatty acid synthesis. However, ACC itself was not identified as a direct FIN56 target and the detailed mechanism linking FIN56 to ACC remains to be understood.


Global Survey of Cell Death Mechanisms Reveals Metabolic Regulation of Ferroptosis
ACC inhibitor prevents GPX4 protein degradationa. Effects of the mevalonate pathway modulators and ACC inhibitor on GPX4 abundance with or without FIN56. The corresponding gel is shown in Supplementary Fig. 12. b. Lipid peroxide levels upon TOFA or αToc treatments. c. Effects of TOFA and αToc on FIN56 lethality. d. Model of FIN56’s mechanism of action. Dotted arrows indicate the mechanistic details are still elusive. Statistical significance (paired two-tailed t-test) – *: p < 0.05, ††: p < 0.001, n.s.: not significant. Supplementary Fig. 11d also supports that the mevalonate pathway modulators did not change GPX4 abundance. a–c were performed in biological triplicates. mean and s.e.m. are shown in a; single representative results were shown in b and c. error-bars are s.e.m. of technical triplicates in c.
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Related In: Results  -  Collection

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Figure 6: ACC inhibitor prevents GPX4 protein degradationa. Effects of the mevalonate pathway modulators and ACC inhibitor on GPX4 abundance with or without FIN56. The corresponding gel is shown in Supplementary Fig. 12. b. Lipid peroxide levels upon TOFA or αToc treatments. c. Effects of TOFA and αToc on FIN56 lethality. d. Model of FIN56’s mechanism of action. Dotted arrows indicate the mechanistic details are still elusive. Statistical significance (paired two-tailed t-test) – *: p < 0.05, ††: p < 0.001, n.s.: not significant. Supplementary Fig. 11d also supports that the mevalonate pathway modulators did not change GPX4 abundance. a–c were performed in biological triplicates. mean and s.e.m. are shown in a; single representative results were shown in b and c. error-bars are s.e.m. of technical triplicates in c.
Mentions: Modulators of the mevalonate pathway, such as idebenone, are potent suppressors of ferroptosis, particularly of direct and indirect GPX4 inhibitors (FIN56 and (1S,3R)-RSL3) (Fig. 5h); however, these compounds did not block the decrease of GPX4 protein upon FIN56 treatment or induce its overexpression (Fig. 6a, Supplementary Fig. 12), indicating there may be an additional pathway that regulates GPX4 protein level in response to FIN56 treatment. We discovered that 5-(tetradecyloxy)-2-furoic Acid (TOFA), an inhibitor of acetyl-CoA carboxylase (ACC), inhibited the loss of GPX4. TOFA was also found to be a potent suppressor of FIN56 and suppressed lipid ROS generation upon FIN56 treatment (Fig. 6b,c). ACC is an enzyme involved in fatty acid synthesis. However, ACC itself was not identified as a direct FIN56 target and the detailed mechanism linking FIN56 to ACC remains to be understood.

View Article: PubMed Central - PubMed

ABSTRACT

Apoptosis is known as programmed cell death. Some non-apoptotic cell death is increasingly recognized as genetically controlled, or &lsquo;regulated&rsquo;. However, the full extent and diversity of these alternative cell death mechanisms remains uncharted. Here, we surveyed the landscape of pharmacologically-accessible cell death mechanisms. Of 56 caspase-independent lethal compounds, modulatory profiling revealed ten inducing three types of regulated non-apoptotic cell death. Lead optimization of one of the ten resulted in the discovery of FIN56, a specific inducer of ferroptosis. Ferroptosis occurs when the lipid repair enzyme GPX4 is inhibited. We found that FIN56 promotes degradation of GPX4. We performed chemoproteomics to reveal that FIN56 also binds to and activates squalene synthase, an enzyme involved in the cholesterol synthesis, in a manner independent of GPX4 degradation. These discoveries reveal that dysregulation of lipid metabolism is associated with ferroptosis. This systematic approach is a means to discover and characterize novel cell death phenotypes.

No MeSH data available.


Related in: MedlinePlus