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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.


Modulatory profiling revealed three types of regulated non-apoptotic cell deatha. Experimental scheme to identify regulated non-apoptotic cell death inducers with high modulatability. The numbers in red are the number of compounds satisfying each criterion. b. Hierarchical clustering of modulatory profiles of 10 CILs with high modulatability and 30 characterized lethal compounds from several classes of lethal mechanisms. Lethal compounds are shown on the right. 10 CILs are indicated in red. 46 modulators are shown on the bottom (28 death modulators in 2 cell lines, HT-1080 or BJeLR). Antioxidants and iron-chelators are indicated in brown. A detailed list of modulators is shown in the Supplementary Table 2. Supplementary Fig. 1–4 show additional data on the CIL screening scheme, modulatory profiling scheme, and structures and characterization of ten regulated non-apoptotic cell death inducers.
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Figure 1: Modulatory profiling revealed three types of regulated non-apoptotic cell deatha. Experimental scheme to identify regulated non-apoptotic cell death inducers with high modulatability. The numbers in red are the number of compounds satisfying each criterion. b. Hierarchical clustering of modulatory profiles of 10 CILs with high modulatability and 30 characterized lethal compounds from several classes of lethal mechanisms. Lethal compounds are shown on the right. 10 CILs are indicated in red. 46 modulators are shown on the bottom (28 death modulators in 2 cell lines, HT-1080 or BJeLR). Antioxidants and iron-chelators are indicated in brown. A detailed list of modulators is shown in the Supplementary Table 2. Supplementary Fig. 1–4 show additional data on the CIL screening scheme, modulatory profiling scheme, and structures and characterization of ten regulated non-apoptotic cell death inducers.

Mentions: Towards mapping the landscape of cell death, we sought small molecule inducers of regulated, non-apoptotic cell death (Fig. 1a). We tested 3,169 lethal compounds for induction of caspase-independent cell death in HT-1080 fibrosarcoma cells and BJeLR engineered transformed fibroblasts, the cell lines used for the modulatory profiling experiment16. We found that 451 compounds (14%) triggered cell death without activation of caspases 3/7, detected using a fluorogenic substrate. These compounds were defined as ‘caspase-3/7-independent lethals’ (CILs) (Supplementary Results, Supplementary Fig. 1, Supplementary Note 1). Thus, while most lethal compounds activate caspase activity (irrespective of whether caspase activity is required for their lethality), a significant number of compounds were lethal without activating cleavage of this fluorogenic caspase activity probe.


Global Survey of Cell Death Mechanisms Reveals Metabolic Regulation of Ferroptosis
Modulatory profiling revealed three types of regulated non-apoptotic cell deatha. Experimental scheme to identify regulated non-apoptotic cell death inducers with high modulatability. The numbers in red are the number of compounds satisfying each criterion. b. Hierarchical clustering of modulatory profiles of 10 CILs with high modulatability and 30 characterized lethal compounds from several classes of lethal mechanisms. Lethal compounds are shown on the right. 10 CILs are indicated in red. 46 modulators are shown on the bottom (28 death modulators in 2 cell lines, HT-1080 or BJeLR). Antioxidants and iron-chelators are indicated in brown. A detailed list of modulators is shown in the Supplementary Table 2. Supplementary Fig. 1–4 show additional data on the CIL screening scheme, modulatory profiling scheme, and structures and characterization of ten regulated non-apoptotic cell death inducers.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4920070&req=5

Figure 1: Modulatory profiling revealed three types of regulated non-apoptotic cell deatha. Experimental scheme to identify regulated non-apoptotic cell death inducers with high modulatability. The numbers in red are the number of compounds satisfying each criterion. b. Hierarchical clustering of modulatory profiles of 10 CILs with high modulatability and 30 characterized lethal compounds from several classes of lethal mechanisms. Lethal compounds are shown on the right. 10 CILs are indicated in red. 46 modulators are shown on the bottom (28 death modulators in 2 cell lines, HT-1080 or BJeLR). Antioxidants and iron-chelators are indicated in brown. A detailed list of modulators is shown in the Supplementary Table 2. Supplementary Fig. 1–4 show additional data on the CIL screening scheme, modulatory profiling scheme, and structures and characterization of ten regulated non-apoptotic cell death inducers.
Mentions: Towards mapping the landscape of cell death, we sought small molecule inducers of regulated, non-apoptotic cell death (Fig. 1a). We tested 3,169 lethal compounds for induction of caspase-independent cell death in HT-1080 fibrosarcoma cells and BJeLR engineered transformed fibroblasts, the cell lines used for the modulatory profiling experiment16. We found that 451 compounds (14%) triggered cell death without activation of caspases 3/7, detected using a fluorogenic substrate. These compounds were defined as ‘caspase-3/7-independent lethals’ (CILs) (Supplementary Results, Supplementary Fig. 1, Supplementary Note 1). Thus, while most lethal compounds activate caspase activity (irrespective of whether caspase activity is required for their lethality), a significant number of compounds were lethal without activating cleavage of this fluorogenic caspase activity probe.

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.