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)

Death-associated protein (Daxx) deletion mutant (aa 501-625) has been known to be an inducer of apoptosis. In this study, we observed that the Bax-dependent mitochondrial death signaling pathway plays an important role in Daxx501-625-induced apoptosis. Daxx fragment-induced activation of caspase-9 and -3 was mediated through the apoptosis signal-regulating kinase 1 (ASK1)-MEK-c-Jun-N-terminal kinase (JNK)/p38-Bax pathway. By overexpressing JNK-binding domain (JBD) of JIP1, a JNK-inhibitory protein, and treatment with SB203580, a specific p38 inhibitor, DU-145 cells were made resistant to Daxx501-625-induced apoptosis. Capase-3 deficiency, Bax deficiency, or overexpression of a dominant-negative caspase-9 mutant prevented apoptosis, even though the Daxx501-625 fragment still activated the ASK1-MEK-MAPK pathway. Interestingly, Daxx501-625-induced Bcl-2 interacting domain (Bid) cleavage was suppressed in the dominant-negative caspase-9 mutant cells, whereas Bim was still phosphorylated in these cells. These results suggest that cleavage of Bid occurs downstream of caspase-9 activation. In contrast, phosphorylation of Bim is upstream of caspase-9 activation. Taken together, our results suggest that Daxx501-625-induced apoptosis is mediated through the ASK1-MEK-JNK/p38-Bim-Bax-dependent caspase pathway.
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PMID:Daxx deletion mutant (amino acids 501-625)-induced apoptosis occurs through the JNK/p38-Bax-dependent mitochondrial pathway. 1525 8

Arsenic trioxide (As2O3) is used clinically to treat acute promyelocytic leukemia but is less successful in other malignancies. To identify targets for potential combination therapies, we have begun to characterize signaling pathways leading to As2O3-induced cytotoxicity. Previously, we described the requirement for a reactive oxygen species-mediated, SEK1/c-Jun NH2-terminal kinase (JNK) pathway to induce apoptosis. AKT inhibits several steps in this pathway; therefore, we postulated that As2O3 might decrease its activity. Indeed, As2O3 decreases not only AKT activity but also total AKT protein, and sensitivity to As2O3 correlates with the degree of AKT protein decrease. Decreased AKT expression further correlates with JNK activation and the release of AKT from the JNK-interacting protein 1 scaffold protein known to assemble the mitogen-activated protein kinase cascade. We found that As2O3 regulates AKT protein stability without significant effects on its transcription or translation. We show that As2O3 decreases AKT protein via caspase-mediated degradation, abrogated by caspase-6, caspase-8, caspase-9, and caspase-3 inhibitors but not proteosome inhibitors. Furthermore, As2O3 enhances the ability of a heat shock protein 90 inhibitor to decrease AKT expression and increase growth inhibition. This suggests that As2O3 may be useful in combination therapies that target AKT pathways or in tumors that have constitutively active AKT expression.
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PMID:Arsenic trioxide decreases AKT protein in a caspase-dependent manner. 1856 39