Glutathione peroxidase-1 regulates ASK1-dependent apoptosis via interaction with TRAF2 in RIPK3-negative cancer cells.
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ABSTRACT:
SUBMITTER: Lee S
PROVIDER: S-EPMC8257591 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Glutathione peroxidase-1 (GPx-1) is a selenocysteine-containing enzyme that plays a major role in the reductive detoxification of peroxides in cells. In permanently transfected cells with approximate 2-fold overexpression of GPx-1, we found that intracellular accumulation of oxidants in response to exogenous hydrogen peroxide was diminished, as was epidermal growth factor receptor (EGFR)-mediated Akt activation in response to hydrogen peroxide or EGF stimulation. Knockdown of GPx-1 augmented EGFR-mediated Akt activation, whereas overexpression of catalase decreased Akt activation, suggesting that EGFR signaling is regulated by redox mechanisms. To determine whether mitochondrial oxidants played a role in these processes, cells were pretreated with a mitochondrial uncoupler prior to EGF stimulation. Inhibition of mitochondrial function attenuated EGF-mediated activation of Akt in control cells but had no additional effect in GPx-1-overexpressing cells, suggesting that GPx-1 overexpression decreased EGFR signaling by decreasing mitochondrial oxidants. Consistent with this finding, GPx-1 overexpression decreased global protein disulfide bond formation, which is dependent on mitochondrially produced oxidants. GPx-1 overexpression, in permanently transfected or adenovirus-treated cells, also caused overall mitochondrial dysfunction with a decrease in mitochondrial potential and a decrease in ATP production. GPx-1 overexpression also decreased EGF- and serum-mediated [(3)H]thymidine incorporation, indicating that alterations in GPx-1 can attenuate cell proliferation. Taken together, these data suggest that GPx-1 can modulate redox-dependent cellular responses by regulating mitochondrial function.
| S-EPMC2673260 | biostudies-literature
Project description:Triple-negative breast cancer (TNBC) cells, which do not express genes for estrogen receptor (ER), progesterone receptor (PR), and Her2/neu, develop highly aggressive and metastatic tumors resistant to chemo- and hormonal therapies. We found that expression of glutathione peroxidase-1 (Gpx1) is silenced in the non-TNBC cells but significantly maintained in the TNBC cell lines. Such Gpx1 expression plays a vital role in the metastasis of TNBC cells by regulating cell adhesion. Transcriptomic and signaling pathway analyses demonstrate that depletion of Gpx1 essentially impairs cell adhesion/spreading by down-regulating FAK/c-Src activation. Mechanistically, Gpx1 interacts with FAK kinase and prevents the kinase inactivation by H2O2, not lipid hydroperoxide. As a result, depletion of Gpx1 suppresses lung metastasis of TNBC cells in vivo. Overall, our study identifies that Gpx1 is a redox safeguard of FAK kinase and its inhibition may provide an effective way to control the metastasis of deadly malignant TNBC.
| S-EPMC6906704 | biostudies-literature
Project description:Human caspase-4 and its mouse homolog caspase-11 are receptors for cytoplasmic lipopolysaccharide. Activation of the caspase-4/11-dependent NLRP3 inflammasome is required for innate defense and endotoxic shock, but how caspase-4/11 is modulated remains unclear. Here, we show that mice lacking the oxidative stress sensor glutathione peroxidase 8 (GPx8) are more susceptible to colitis and endotoxic shock, and exhibit reduced richness and diversity of the gut microbiome. C57BL/6 mice that underwent adoptive cell transfer of GPx8-deficient macrophages displayed a similar phenotype of enhanced colitis, indicating a critical role of GPx8 in macrophages. GPx8 binds covalently to caspase-4/11 via disulfide bonding between cysteine 79 of GPx8 and cysteine 118 of caspase-4 and thus restrains caspase-4/11 activation, while GPx8 deficiency leads to caspase-4/11-induced inflammation during colitis and septic shock. Inhibition of caspase-4/11 activation with small molecules reduces the severity of colitis in GPx8-deficient mice. Notably, colonic tissues from patients with ulcerative colitis display low levels of Gpx8 and high caspase-4 expression. In conclusion, these results suggest that GPx8 protects against colitis by negatively regulating caspase-4/11 activity.
| S-EPMC6949489 | biostudies-literature
Project description:Cell survival and death-inducing signals are tightly associated with each other, and the decision as to whether a cell survives or dies is determined by controlling the relationship between these signals. However, the mechanism underlying the reciprocal regulation of such signals remains unclear. In this study, we reveal a functional association between PDK1 (3-phosphoinositide-dependent protein kinase 1), a critical mediator of cell survival, and ASK1 (apoptosis signal-regulating kinase 1), an apoptotic stress-activated MAPKKK. The physical association between PDK1 and ASK1 is mediated through the pleckstrin homology domain of PDK1 and the C-terminal regulatory domain of ASK1 and is decreased by ASK1-activating stimuli, such as H(2)O(2), tumor necrosis factor alpha, thapsigargin, and ionomycin, as well as insulin, a PDK1 stimulator. Wild-type PDK1, but not kinase-dead PDK1, negatively regulates ASK1 activity by phosphorylating Ser(967), a binding site for 14-3-3 protein, on ASK1. PDK1 functionally suppresses ASK1-mediated AP-1 transactivation and H(2)O(2)-mediated apoptosis in a kinase-dependent manner. On the other hand, ASK1 has been shown to inhibit PDK1 functions, including PDK1-mediated regulation of apoptosis and cell growth, by phosphorylating PDK1 at Ser(394) and Ser(398), indicating that these putative phosphorylation sites are involved in the negative regulation of PDK1 activity. These results provide evidence that PDK1 and ASK1 directly interact and phosphorylate each other and act as negative regulators of their respective kinases in resting cells.
| S-EPMC2807298 | biostudies-literature
Project description:The role of glutathione peroxidase 4 (GPX4) in ferroptosis and various cancers is well-established; however, its specific contribution to colorectal cancer has been unclear. Surprisingly, in a genetic mouse model of colon tumors, the deletion of GPX4 specifically in colon epithelial cells increased tumor burden but decreased oxidized glutathione. Notably, this specific GPX4 deletion did not enhance susceptibility to dextran sodium sulfate (DSS)-induced colitis in mice with varied iron diets but showed vulnerability in mice with a vitamin E-deficient diet. Additionally, a high manganese diet heightened susceptibility, while a low manganese diet reduced DSS-induced colitis in colon epithelial-specific GPX4-deficient mice. Strikingly, the low manganese diet also significantly reduced colorectal cancer formation in both colon epithelial-specific GPX4-deficient and wildtype mice. Mechanistically, antioxidant proteins, especially manganese-dependent superoxide dismutase (MnSOD or SOD2), correlated with disease severity. Treatment with tempol, a superoxide dismutase mimetic radical scavenger, suppressed GPX4 deficiency-induced colorectal tumors. In conclusion, the study elucidates the critical role of GPX4 in inhibiting colorectal cancer progression by regulating oxidative stress in a manganese-dependent manner. The findings underscore the intricate interactions between GPX4, dietary factors, and their collective influence on colorectal cancer development, providing potential insights for personalized therapeutic strategies.
| S-EPMC10802749 | biostudies-literature
Project description:BackgroundPlatinum-based chemotherapy is effective in inducing shrinkage of primary lung cancer lesions; however, it shows finite therapeutic efficacy in patients suffering from brain metastasis (BM). The intrinsic changes of BM cells, which contribute to the poor results remain unknown.MethodsPlatinum drug-sensitivity was assessed by utilizing a preclinical BM model of PC9 lung adenocarcinoma cells in vitro and in vivo. High consumption of glutathione (GSH) and two associated upregulated proteins (GPX4 and GSTM1) in BM were identified by integrated metabolomics and proteomics in cell lines and verified by clinical serum sample. Gain-of-function and rescue experiments were implemented to reveal the impact and mechanism of GPX4 and GSTM1 on the chemosensitivity in BM. The interaction between GPX4 and GSTM1 was examined by immunoblotting and immunoprecipitation. The mechanism of upregulation of GPX4 was further uncovered by luciferase reporter assay, immunoprecipitation, and electrophoretic mobility shift assay.ResultsThe derivative brain metastatic subpopulations (PC9-BrMs) of parental cells PC9 developed obvious resistance to platinum. Radically altered profiles of BM metabolism and protein expression compared with primary lung cancer cells were described and GPX4 and GSTM1 were identified as being responsible for the high consumption of GSH, leading to decreased chemosensitivity by negatively regulating ferroptosis. Besides, GSTM1 was found regulated by GPX4, which was transcriptionally activated by the Wnt/NR2F2 signaling axis in BM.ConclusionsCollectively, our findings demonstrated that Wnt/NR2F2/GPX4 promoted acquired chemoresistance by suppressing ferroptosis with high consumption of GSH. GPX4 inhibitor was found to augment the anticancer effect of platinum drugs in lung cancer BM, providing novel strategies for lung cancer patients with BM.
| S-EPMC8473645 | biostudies-literature
Project description:The mechanistic target of rapamycin (mTOR) has a key role in the integration of various physiological stimuli to regulate several cell growth and metabolic pathways. mTOR primarily functions as a catalytic subunit in two structurally related but functionally distinct multi-component kinase complexes, mTOR complex 1 (mTORC1) and mTORC2 (refs 1, 2). Dysregulation of mTOR signalling is associated with a variety of human diseases, including metabolic disorders and cancer. Thus, both mTORC1 and mTORC2 kinase activity is tightly controlled in cells. mTORC1 is activated by both nutrients and growth factors, whereas mTORC2 responds primarily to extracellular cues such as growth-factor-triggered activation of PI3K signalling. Although both mTOR and GβL (also known as MLST8) assemble into mTORC1 and mTORC2 (refs 11, 12, 13, 14, 15), it remains largely unclear what drives the dynamic assembly of these two functionally distinct complexes. Here we show, in humans and mice, that the K63-linked polyubiquitination status of GβL dictates the homeostasis of mTORC2 formation and activation. Mechanistically, the TRAF2 E3 ubiquitin ligase promotes K63-linked polyubiquitination of GβL, which disrupts its interaction with the unique mTORC2 component SIN1 (refs 12, 13, 14) to favour mTORC1 formation. By contrast, the OTUD7B deubiquitinase removes polyubiquitin chains from GβL to promote GβL interaction with SIN1, facilitating mTORC2 formation in response to various growth signals. Moreover, loss of critical ubiquitination residues in GβL, by either K305R/K313R mutations or a melanoma-associated GβL(ΔW297) truncation, leads to elevated mTORC2 formation, which facilitates tumorigenesis, in part by activating AKT oncogenic signalling. In support of a physiologically pivotal role for OTUD7B in the activation of mTORC2/AKT signalling, genetic deletion of Otud7b in mice suppresses Akt activation and Kras-driven lung tumorigenesis in vivo. Collectively, our study reveals a GβL-ubiquitination-dependent switch that fine-tunes the dynamic organization and activation of the mTORC2 kinase under both physiological and pathological conditions.
| S-EPMC5695540 | biostudies-literature
Project description:ObjectiveTo characterize normal and malformed embryos within the same litters from control and diabetic rats for expression of genes related to metabolism of reactive oxygen species (ROS) or glucose as well as developmental genes.Research design and methodsEmbryos from nondiabetic and streptozotocin-induced diabetic rats were collected on gestational day 11 and evaluated for gene expression (PCR) and distribution of activated caspase-3 and glutathione peroxidase (Gpx)-1 by immunohistochemistry.ResultsMaternal diabetes (MD group) caused growth retardation and an increased malformation rate in the embryos of MD group rats compared with those of controls (N group). We found decreased gene expression of Gpx-1 and increased expression of vascular endothelial growth factor-A (Vegf-A) in malformed embryos of diabetic rats (MDm group) compared with nonmalformed littermates (MDn group). Alterations of messenger RNA levels of other genes were similar in MDm and MDn embryos. Thus, expression of copper zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), and sonic hedgehog homolog (Shh) were decreased, and bone morphogenetic protein-4 (Bmp-4) was increased, in the MD embryos compared with the N embryos. In MDm embryos, we detected increased activated caspase-3 immunostaining in the first visceral arch and cardiac area and decreased Gpx-1 immunostaining in the cardiac tissue; both findings differed from the caspase/Gpx-1 immunostaining of the MDn and N embryos.ConclusionsMaternal diabetes causes growth retardation, congenital malformations, and decreased general antioxidative gene expression in the embryo. In particular, enhanced apoptosis of the first visceral arch and heart, together with decreased cardiac Gpx-1 levels, may compromise the mandible and heart and thus cause an increased risk of developing congenital malformation.
| S-EPMC2584142 | biostudies-literature
Project description:We demonstrate that the mitochondrial isoform of rice GPX (OsGPX3) is involved in the responses to the phytohormone abscisic acid (ABA) and in epigenetic modifications. Silenced plants for OsGPX3 present important changes in the accumulation of proteins related to these processes.
2021-01-27 | PXD015788 | Pride
Project description:Many DNA viruses develop various strategies to inhibit cell death to facilitate their replication. However, whether influenza A virus (IAV), a fast-replicating RNA virus, attenuates cell death remains unknown. Here, we report that IAV infection induces TAK1 phosphorylation in a murine alveolar epithelial cell line (LET1) and a murine fibroblastoma cell line (L929). The TAK1-specific inhibitor 5Z-7-Oxzeneonal (5Z) and TAK1 knockout significantly enhance IAV-induced apoptosis, as evidenced by increased PARP, caspase-8, and caspase-3 cleavage. TAK1 inhibition also increases necroptosis as evidenced by increased RIPK1S166, RIPK3T231/S232, and MLKLS345 phosphorylation. Mechanistically, TAK1 activates IKK, which phosphorylates RIPK1S25 and inhibits its activation. TAK1 also activates p38 and its downstream kinase MK2, which phosphorylates RIPK1S321 but does not affect RIPK1 activation. Further investigation revealed that the RIPK1 inhibitor Nec-1 and RIPK1 knockout abrogate IAV-induced apoptosis and necroptosis; re-expression of wild-type but not kinase-dead (KD)-RIPK1 restores IAV-induced cell death. ZBP1 knockout abrogates IAV-induced cell death, whereas RIPK3 knockout inhibits IAV-induced necroptosis but not apoptosis. 5Z treatment enhances IAV-induced cell death and slightly reduces the inflammatory response in the lungs of H1N1 virus-infected mice and prolongs the survival of IAV-infected mice. Our study provides evidence that IAV activates TAK1 to suppress RIPK1-dependent apoptosis and necroptosis, and that RIPK3 is required for IAV-induced necroptosis but not apoptosis in epithelial cells.
| S-EPMC11264382 | biostudies-literature