RESUMEN
The role of the mitochondrial electron transport chain (ETC) in regulating ferroptosis is not fully elucidated. Here, we reveal that pharmacological inhibition of the ETC complex I reduces ubiquinol levels while decreasing ATP levels and activating AMP-activated protein kinase (AMPK), the two effects known for their roles in promoting and suppressing ferroptosis, respectively. Consequently, the impact of complex I inhibitors on ferroptosis induced by glutathione peroxidase 4 (GPX4) inhibition is limited. The pharmacological inhibition of complex I in LKB1-AMPK-inactivated cells, or genetic ablation of complex I (which does not trigger apparent AMPK activation), abrogates the AMPK-mediated ferroptosis-suppressive effect and sensitizes cancer cells to GPX4-inactivation-induced ferroptosis. Furthermore, complex I inhibition synergizes with radiotherapy (RT) to selectively suppress the growth of LKB1-deficient tumors by inducing ferroptosis in mouse models. Our data demonstrate a multifaceted role of complex I in regulating ferroptosis and propose a ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers.
Asunto(s)
Proteínas Quinasas Activadas por AMP , Complejo I de Transporte de Electrón , Ferroptosis , Fosfolípido Hidroperóxido Glutatión Peroxidasa , Proteínas Serina-Treonina Quinasas , Ferroptosis/genética , Ferroptosis/efectos de los fármacos , Animales , Humanos , Proteínas Quinasas Activadas por AMP/metabolismo , Proteínas Quinasas Activadas por AMP/genética , Complejo I de Transporte de Electrón/metabolismo , Complejo I de Transporte de Electrón/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Ratones , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Fosfolípido Hidroperóxido Glutatión Peroxidasa/genética , Línea Celular Tumoral , Neoplasias/genética , Neoplasias/patología , Neoplasias/metabolismo , Neoplasias/tratamiento farmacológico , Quinasas de la Proteína-Quinasa Activada por el AMP/genética , Mitocondrias/metabolismo , Mitocondrias/genética , Mitocondrias/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Transducción de Señal , FemeninoRESUMEN
How cells coordinate cell cycling with cell survival and death remains incompletely understood. Here, we show that cell cycle arrest has a potent suppressive effect on ferroptosis, a form of regulated cell death induced by overwhelming lipid peroxidation at cellular membranes. Mechanistically, cell cycle arrest induces diacylglycerol acyltransferase (DGAT)-dependent lipid droplet formation to sequester excessive polyunsaturated fatty acids (PUFAs) that accumulate in arrested cells in triacylglycerols (TAGs), resulting in ferroptosis suppression. Consequently, DGAT inhibition orchestrates a reshuffling of PUFAs from TAGs to phospholipids and re-sensitizes arrested cells to ferroptosis. We show that some slow-cycling antimitotic drug-resistant cancer cells, such as 5-fluorouracil-resistant cells, have accumulation of lipid droplets and that combined treatment with ferroptosis inducers and DGAT inhibitors effectively suppresses the growth of 5-fluorouracil-resistant tumors by inducing ferroptosis. Together, these results reveal a role for cell cycle arrest in driving ferroptosis resistance and suggest a ferroptosis-inducing therapeutic strategy to target slow-cycling therapy-resistant cancers.
Asunto(s)
Ferroptosis , Neoplasias , Humanos , Gotas Lipídicas/metabolismo , Ácidos Grasos Insaturados/metabolismo , Peroxidación de Lípido , Triglicéridos/metabolismo , Puntos de Control del Ciclo Celular , Neoplasias/metabolismo , Diacilglicerol O-Acetiltransferasa/metabolismo , Fluorouracilo/farmacología , Fluorouracilo/uso terapéuticoRESUMEN
Ferroptosis has been recognized as a unique cell death modality driven by excessive lipid peroxidation and unbalanced cellular metabolism. In this study, we established a protein interaction landscape for ferroptosis pathways through proteomic analyses, and identified choline/ethanolamine phosphotransferase 1 (CEPT1) as a lysophosphatidylcholine acyltransferase 3 (LPCAT3)-interacting protein that regulates LPCAT3 protein stability. In contrast to its known role in promoting phospholipid synthesis, we showed that CEPT1 suppresses ferroptosis potentially by interacting with phospholipases and breaking down certain pro-ferroptotic polyunsaturated fatty acid (PUFA)-containing phospholipids. Together, our study reveals a previously unrecognized role of CEPT1 in suppressing ferroptosis.
RESUMEN
Resistance to poly (ADP-ribose) polymerase inhibitors (PARPi) limits the therapeutic efficacy of PARP inhibition in treating breast cancer susceptibility gene 1 (BRCA1)-deficient cancers. Here we reveal that BRCA1 has a dual role in regulating ferroptosis. BRCA1 promotes the transcription of voltage-dependent anion channel 3 (VDAC3) and glutathione peroxidase 4 (GPX4); consequently, BRCA1 deficiency promotes cellular resistance to erastin-induced ferroptosis but sensitizes cancer cells to ferroptosis induced by GPX4 inhibitors (GPX4i). In addition, nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and defective GPX4 induction unleash potent ferroptosis in BRCA1-deficient cancer cells upon PARPi and GPX4i co-treatment. Finally, we show that xenograft tumors derived from patients with BRCA1-mutant breast cancer with PARPi resistance exhibit decreased GPX4 expression and high sensitivity to PARP and GPX4 co-inhibition. Our results show that BRCA1 deficiency induces a ferroptosis vulnerability to PARP and GPX4 co-inhibition and inform a therapeutic strategy for overcoming PARPi resistance in BRCA1-deficient cancers. Significance: BRCA1 deficiency promotes resistance to erastin-induced ferroptosis via blocking VDAC3 yet renders cancer cells vulnerable to GPX4i-induced ferroptosis via inhibiting GPX4. NCOA4 induction and defective GPX4 further synergizes GPX4i with PARPi to induce ferroptosis in BRCA1-deficient cancers and targeting GPX4 mitigates PARPi resistance in those cancers. See related commentary by Alborzinia and Friedmann Angeli, p. 1372.
Asunto(s)
Proteína BRCA1 , Ferroptosis , Fosfolípido Hidroperóxido Glutatión Peroxidasa , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Ferroptosis/efectos de los fármacos , Humanos , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Fosfolípido Hidroperóxido Glutatión Peroxidasa/genética , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéutico , Proteína BRCA1/genética , Femenino , Animales , Ratones , Línea Celular Tumoral , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Neoplasias de la Mama/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Coactivadores de Receptor NuclearRESUMEN
The cystine transporter solute carrier family 7 member 11 (SLC7A11; also called xCT) protects cancer cells from oxidative stress and is overexpressed in many cancers. Here we report a surprising finding that, whereas moderate overexpression of SLC7A11 is beneficial for cancer cells treated with H2O2, a common oxidative stress inducer, its high overexpression dramatically increases H2O2-induced cell death. Mechanistically, high cystine uptake in cancer cells with high overexpression of SLC7A11 in combination with H2O2 treatment results in toxic buildup of intracellular cystine and other disulfide molecules, NADPH depletion, redox system collapse, and rapid cell death (likely disulfidptosis). We further show that high overexpression of SLC7A11 promotes tumor growth but suppresses tumor metastasis, likely because metastasizing cancer cells with high expression of SLC7A11 are particularly susceptible to oxidative stress. Our findings reveal that SLC7A11 expression level dictates cancer cells' sensitivity to oxidative stress and suggests a context-dependent role for SLC7A11 in tumor biology.
Asunto(s)
Cistina , Neoplasias , Cistina/metabolismo , Línea Celular Tumoral , Peróxido de Hidrógeno/farmacología , Peróxido de Hidrógeno/metabolismo , Estrés Oxidativo , Disulfuros/metabolismo , Sistema de Transporte de Aminoácidos y+/genética , Sistema de Transporte de Aminoácidos y+/metabolismo , Neoplasias/genéticaRESUMEN
SLC7A11-mediated cystine uptake suppresses ferroptosis yet promotes cell death under glucose starvation; the nature of the latter cell death remains unknown. Here we show that aberrant accumulation of intracellular disulfides in SLC7A11high cells under glucose starvation induces a previously uncharacterized form of cell death distinct from apoptosis and ferroptosis. We term this cell death disulfidptosis. Chemical proteomics and cell biological analyses showed that glucose starvation in SLC7A11high cells induces aberrant disulfide bonds in actin cytoskeleton proteins and F-actin collapse in a SLC7A11-dependent manner. CRISPR screens and functional studies revealed that inactivation of the WAVE regulatory complex (which promotes actin polymerization and lamellipodia formation) suppresses disulfidptosis, whereas constitutive activation of Rac promotes disulfidptosis. We further show that glucose transporter inhibitors induce disulfidptosis in SLC7A11high cancer cells and suppress SLC7A11high tumour growth. Our results reveal that the susceptibility of the actin cytoskeleton to disulfide stress mediates disulfidptosis and suggest a therapeutic strategy to target disulfidptosis in cancer treatment.
Asunto(s)
Disulfuros , Neoplasias , Humanos , Neoplasias/metabolismo , Apoptosis , Citoesqueleto de Actina/metabolismo , Glucosa/metabolismoRESUMEN
Lipid peroxidation occurs under conditions where reactive oxygen species (ROS) readily react with vulnerable lipids on cell membranes. Polyunsaturated fatty acids (PUFAs) are highly susceptible to lipid peroxidation because of their unstable double bonds. Because the cell membrane is particularly rich in PUFAs, it is often the site at which many lipid peroxidation chain reactions occur. Lipid peroxidation is considered the ultimate trigger of ferroptosis, an iron-dependent form of non-apoptotic cell death. Radiotherapy is a common cancer treatment that uses high-energy ionizing radiation to kill cancer cells, and radiation-induced cell death is partially attributed to lipid peroxidation-driven ferroptosis. Here, we describe methods to assess lipid peroxidation in irradiated cells. The same techniques can be applied to a variety of lipid peroxidation measurements under different treatment conditions.
Asunto(s)
Hierro , Muerte Celular/fisiología , Membrana Celular/metabolismo , Hierro/metabolismo , Peroxidación de Lípido/fisiología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Targeting ferroptosis, a unique cell death modality triggered by unrestricted lipid peroxidation, in cancer therapy is hindered by our incomplete understanding of ferroptosis mechanisms under specific cancer genetic contexts. KEAP1 (kelch-like ECH associated protein 1) is frequently mutated or inactivated in lung cancers, and KEAP1 mutant lung cancers are refractory to most therapies, including radiotherapy. In this study, we identify ferroptosis suppressor protein 1 (FSP1, also known as AIFM2) as a transcriptional target of nuclear factor erythroid 2-related factor 2 (NRF2) and reveal that the ubiquinone (CoQ)-FSP1 axis mediates ferroptosis- and radiation- resistance in KEAP1 deficient lung cancer cells. We further show that pharmacological inhibition of the CoQ-FSP1 axis sensitizes KEAP1 deficient lung cancer cells or patient-derived xenograft tumors to radiation through inducing ferroptosis. Together, our study identifies CoQ-FSP1 as a key downstream effector of KEAP1-NRF2 pathway and as a potential therapeutic target for treating KEAP1 mutant lung cancers.