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)

The cytokine hepatocyte growth factor/scatter factor (HGF/SF) has been found to protect a variety of epithelial and cancer cell types against cytotoxicity and apoptosis induced by DNA damage, but the specific apoptotic signaling events and the levels at which they are blocked by HGF/SF have not been identified. We found that treatment of MDA-MB-453 human breast cancer cells with adriamycin (also known as doxorubicin, a DNA topoisomerase IIalpha inhibitor) induced a series of time-dependent events, including the mitochondrial release of cytochrome c and apoptosis-inducing factor, mitochondrial membrane depolarization, activation of a set of caspases (caspase-9, -3, -7, -2, and -8), cleavage of poly(ADP-ribose) polymerase (PARP), and up-regulation of expression of the Fas ligand. All of these events were blocked by preincubation of the cells with HGF/SF. In contrast, the pan-caspase inhibitor benzyloxycarbonyl-VAD-fluoromethylketone blocked some of these events (e.g. caspase-3 activation and PARP cleavage) but did not block cytochrome c release or mitochondrial depolarization. These findings suggest that HGF/SF functions, in part, upstream of the mitochondria to block mitochondrial apoptosis signaling, prevent activation of multiple caspases, and protect breast cancer cells against apoptosis.
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PMID:Hepatocyte growth factor/scatter factor blocks the mitochondrial pathway of apoptosis signaling in breast cancer cells. 1157 Dec 97

The mechanisms by which growth factors trigger signal transduction pathways leading to protection against apoptosis are of great interest. In this study, we investigated the effect of hepatocyte growth factor (HGF/SF) and epidermal growth factor (EGF) on adriamycin (ADR)-induced apoptosis. Treatment of human epithelial MKN74 cells with ADR, a DNA topoisomerase IIalpha inhibitor, caused apoptosis. However, cells pretreated with HGF/SF, but not those pretreated with EGF, were resistant to this apoptosis. The protective effect of HGF/SF against the ADR-induced apoptosis was abolished in the presence of either LY294002, an inhibitor of phosphatidylinositol-3'-OH kinase (PI3-K) or 1L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate, an inhibitor of Akt, thus implicating the activation of PI3-K-Akt signaling in the antiapoptotic action of HGF/SF. Immunoblotting analysis revealed that HGF/SF stimulated the sustained phosphorylation of Akt for several hours but that EGF stimulated the phosphorylation only transiently. Furthermore, ADR-induced activation of caspase-9, a downstream molecule of Akt, was inhibited for at least 24 h after HGF/SF stimulation, but it was not affected by EGF stimulation. Cell-surface biotin-labeling analysis showed that the HGF/SF receptor remained on the cell surface until at least 30 min after HGF/SF addition but that the EGF receptor level on the cell surface was attenuated at an earlier time after EGF addition. These results indicate that HGF/SF, but not EGF, transmitted protective signals against ADR-induced apoptosis by causing sustained activation of the PI3-K-Akt signaling pathway. Furthermore, the difference in antiapoptotic capacity between HGF/SF and EGF is explained, at least in part, by the delayed down-regulation of the HGF/SF receptor.
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PMID:Suppression of adriamycin-induced apoptosis by sustained activation of the phosphatidylinositol-3'-OH kinase-Akt pathway. 1457 Sep 4

A total of thirty-nine naphtho[2,3-b]furan-4,9-diones and related compounds were tested for their cytotoxicity against three human normal oral cells (gingival fibroblast, HGF, pulp cell, HPC, periodontal ligament fibroblast, HPLF) and four human tumor cell lines (oral squamous cell carcinoma HSC-2, HSC-3, HSC-4, promyelocytic leukemia HL-60). 2-Acetylnaphtho[2,3-b]furan-4,9-dione [1] was highly cytotoxic to both normal and tumor cells, yielding low tumor-specificity. 2-Acetyl-4,9-dimethoxynaphtho[2,3-b]furan [4], the 2-(3-furanoyl) benzoic acids [5, 6] and the 1,4-naphthoquinones [7, 8] showed much reduced cytototoxicity and low tumor-specificity. The introduction of phenoxy [18], isopropylamino [23] or 2-methylpiperidino [33] groups to the 2-position of naphtho[2,3-b]furan-4,9-dione yielded compounds that showed the greatest tumor-specificity. These compounds, at twice or four times higher concentrations than CC50, induced the activation of caspase-3, caspase-8 and caspase-9 in the HSC-2 and HL-60 cells, but not so apparently in the HSC-4 cells. However, they did not induce internucleosomal DNA fragmentation in the HSC-2 and HSC-4 cells even after 24 hours incubation and only slightly induced DNA fragmentation in the HL-60 cells. Compound [18] induced the production of annexin-positive cells, but did not induce microtubule-associated protein light chain 3 (LC3) accumulation in autophagosomes in LC3-green fluorescent protein (GFP)-transfected HSC-2 cells. These data suggested that naphtho[2,3-b]furan-4,9-diones may induce the early apoptotic marker, without induction of caspase activation and DNA fragmentation in oral squamous cell carcinoma cell lines. Quantitative structure-activity relationship (QSAR) analysis suggests the applicability of the theoretical calculations such as frontier molecular orbital, dipole moments and hydrophobicity in predicting their cytotoxic activity.
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PMID:Tumor-specific cytotoxicity and type of cell death induced by naphtho[2,3-b]furan-4,9-diones and related compounds in human tumor cell lines: relationship to electronic structure. 1933 Nov 86