Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.62 (caspase-9)
 7,507 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was undertaken to determine whether the Bcl-2 family proteins and Smac are regulators of aspirin-mediated apoptosis in a gastric mucosal cell line known as AGS cells. Cells were incubated with varying concentrations of acetylsalicylic acid (ASA; 2-40 mM), with or without preincubation of caspase inhibitors. Apoptosis was characterized by Hoechst staining and DNA-histone-associated complex formation. Antiapoptotic Bcl-2, proapoptotic Bax and Bid, Smac, and cytochrome-c oxidase (COX IV) were analyzed by Western blot analyses from cytosol and mitochondrial fractions. ASA downregulated Bcl-2 protein expression and induced Bax translocation into the mitochondria and cleavage of Bid. In contrast, expression of Smac was significantly decreased in mitochondrial fractions of ASA-treated cells. Bax and Bid involvement in apoptosis regulation was dependent on caspase activation, because caspase-8 inhibition suppressed Bax translocation and Bid processing. Caspase-9 inhibition prevented Smac release from mitochondria. Additionally, increased expression of the oxidative phosphorylation enzyme COX IV was observed in mitochondrial fractions exposed to ASA at concentrations >5 mM. Although caspase-8 inhibition had no effect on aspirin-induced apoptosis and DNA-histone complex formation, caspase-9 inhibition significantly decreased both of these events. We conclude that Bcl-2 protein family members and Smac regulate the apoptotic pathway in a caspase-dependent manner. Our results indicate also that mitochondrial integration and oxidative phosphorylation play a critical role in the pathogenesis of apoptosis in human gastric epithelial cells.
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PMID:Role of mitochondria in aspirin-induced apoptosis in human gastric epithelial cells. 1597 87

Dibutyl phthalate (DBP)-induced germ cell apoptosis contributes to male reproductive toxicity, however, the primary target organelle of DBP or the molecular events triggered by DBP to initiate germ cell apoptosis remain unclear. Our previous studies demonstrated DBP could stimulate the production of intracellular reactive oxygen species (ROS), which served as an upstream mediator of activation of endoplasmic reticulum (ER) stress in mouse spermatocyte-derived GC-2 cells. In the present study, the impacts of DBP-induced ROS generation on the mitochondria-related damage and the associations between ER stress and mitochondrial-related damage were investigated in GC-2 cells. We observed significant decreases of mitochondrial mass, mtDNA copy number, COX IV protein level, and ATP level in DBP-treated GC-2 cells in a dose-dependent manner. And DBP activated mitochondrial-related apoptosis, indicated by the elevation of cytoplasmic cytochrome C (Cyt C) and the activation of caspase-9/3 cascade. Pretreatment with antioxidant melatonin obviously attenuated DBP-induced mitochondrial damage and mitochondrial-dependent apoptosis in GC-2 cells, indicating the role of ROS in DBP-caused testicular toxicity. In response to oxidative stress, the Nrf2/ARE axis was activated in DBP-treated GC-2 cells to counteract ROS overproduction and subsequent mitochondrial damage. Further experiments showed DBP treatment increased the phosphorylated expression of ER stress-related protein PERK. GSK2606414, a specific inhibitor of PERK, partly attenuated the expression of Nrf2. And both DBP-induced mitochondrial damage in GC-2 cells and mitochondrial-dependent apoptosis of the germ cells in rat testes were further aggravated by PERK inhibition. Taken together, our data suggest that PERK regulates the Nrf2/ARE antioxidant pathway functioning as a self-defense mechanism against ROS-related mitochondrial damage induced by DBP in male germ cells.
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PMID:PERK regulates Nrf2/ARE antioxidant pathway against dibutyl phthalate-induced mitochondrial damage and apoptosis dependent of reactive oxygen species in mouse spermatocyte-derived cells. 3091 Jun 7