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

Breast cancer is the most common neoplasm in women and is the leading cause of cancer-related death for women. Therefore, new agents targeting prevention and treatment of breast cancer are urgently needed. The present study first investigates that a novel triterpenoid Methyl 25-Hydroxy-3-oxoolean-12-en-28-oate (AMR-Me) derived from 25-Hydroxy-3-oxoolean-12-en-28-oic acid (AMR) is a potent inhibitor of cell growth by inducing human breast cancer MCF-7 cells to undergo apoptosis. AMR-Me induced DNA fragmentation and PARP degradation which were preceded by changing Bax/Bcl-2 ratios, cytochrome c release, and subsequent induction of pro-caspase-9 and -7 processing in breast carcinoma MCF-7 cells, but it did not act on Fas/Fas ligand pathways and the activation of caspase-8, suggesting AMR-Me triggered the mitochondrial apoptotic pathway. The general caspase blocking peptide VAD partially blocked AMR-Me induced apoptosis. AMR-Me stimulated p38 mitogen-activated protein kinase and c-Jun NH2-terminal kinase (JNK), but not extracellular signal-regulated kinase activation during apoptosis. SP600125, a specific inhibitor for JNK and SB203580, a p38 MAPK-specific inhibitor suppressed AMR-Me induced apoptosis indicating that activation of JNK and p38 MAPKs involved in the mitochondrial activation-mediated cell death pathway. Our results suggest that AMR-Me can utilize two different MAPK signaling pathways for amplifying the apoptosis cascade, is critical for both our understanding of cell death events and development of cancer preventive/therapeutic agents.
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PMID:Novel synthetic triterpenoid methyl 25-hydroxy-3-oxoolean-12-en-28-oate induces apoptosis through JNK and p38 MAPK pathways in human breast adenocarcinoma MCF-7 cells. 1805 3

The resistance to arsenic trioxide (ATO) treatment is relatively common (55-80%) in multiple myeloma patients. This study found that ATO at clinically achievable concentrations (2-7 mumol/l) activated p38 mitogen-activated protein kinase (MAPK) in both myeloma cell lines and primary myeloma cells, a finding not previously well-documented in myeloma cells. Inhibition of p38 MAPK activation by pharmacological inhibitors (SB203580) or downregulation of p38 MAPK by siRNA significantly increased the apoptosis and/or growth inhibition induced by ATO treatment in myeloma cells. Combination of ATO and p38 MAPK inhibition abolished the interleukin-6 enhanced protection of myeloma cells against ATO treatment. The ATO-resistant cell line developed in our laboratory showed an increase in p38 MAPK activation. The increase of apoptosis by the combination of ATO and SB203580 was accompanied by the activation of caspase-9 and caspase-8 suggesting that both extrinsic and intrinsic apoptotic pathways are involved. Additionally, the p38 MAPK activation by ATO was associated with increased phosphorylation and upregulated expression of Heat shock protein 27. These results suggest that ATO-induced p38 MAPK activation plays an important role in the resistance to ATO in myeloma cells and that p38 MAPK inhibition may overcome resistance to ATO treatment in myeloma patients.
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PMID:P38 MAPK inhibition enhancing ATO-induced cytotoxicity against multiple myeloma cells. 1817 54

Although flavopiridol, a semisynthetic flavone, was initially thought to be a specific inhibitor of cyclin-dependent kinases, it has now been shown that flavopiridol mediates antitumor responses through mechanism(s) yet to be defined. We have shown previously that flavopiridol abrogates tumor necrosis factor (TNF)-induced nuclear factor-kappaB (NF-kappaB) activation. In this report, we examined whether this flavone affects other cellular responses activated by TNF. TNF is a potent inducer of activator protein-1 (AP-1), and flavopiridol abrogated this activation in a dose- and time-dependent manner. Flavopiridol also suppressed AP-1 activation induced by various carcinogens and inflammatory stimuli. When examined for its effect on other signaling pathways, flavopiridol inhibited TNF-induced activation of various mitogen-activated protein kinases, including c-Jun NH(2)-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and p44/p42 MAPK. It is noteworthy that this flavone also suppressed TNF-induced activation of Akt, a cell survival kinase, and expression of various antiapoptotic proteins, such as IAP-1, IAP-2, XIAP, Bcl-2, Bcl-xL, and TRAF-1. Flavopiridol also inhibited the TNF-induced induction of intercellular adhesion molecule-1, c-Myc, and c-Fos, all known to mediate tumorigenesis. Moreover, TNF-induced apoptosis was enhanced by flavopiridol through activation of the bid-cytochrome-caspase-9-caspase-3 pathway. Overall, our results clearly suggest that flavopiridol interferes with the TNF cell-signaling pathway, leading to suppression of antiapoptotic mechanisms and enhancement of apoptosis.
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PMID:Flavopiridol suppresses tumor necrosis factor-induced activation of activator protein-1, c-Jun N-terminal kinase, p38 mitogen-activated protein kinase (MAPK), p44/p42 MAPK, and Akt, inhibits expression of antiapoptotic gene products, and enhances apoptosis through cytochrome c release and caspase activation in human myeloid cells. 2730 81

Molecular mechanisms responsible for lymphoma resistance to apoptosis often involve the bcl-2 pathway. In this study, we investigated the cell signaling pathways activated in bcl-2-overexpressing human mantle cell lymphoma cell lines (JVM-2 and Z-138) that have been treated with oblimersen, a molecular gene silencing strategy that effectively suppresses bcl-2 in vitro and in vivo. Z-138 cells expressed higher levels of bcl-2 and were more sensitive to the effects of bcl-2 silencing, mediated by oblimersen or bcl-2 small interfering RNA, in vitro. Tumors derived following injection of Z-138 cells were sensitive to oblimersen as judged by decreases in tumor growth rate and decreases in cell proliferation (as measured by Ki-67). Immunohistochemistry and Western blot analysis of oblimersen-treated Z-138 tumors revealed a dose-dependent decrease in bcl-2 levels and an associated increase in the proapoptotic proteins caspase-3 and caspase-9. Silencing bcl-2 in Z-138 xenografts revealed an associated dose-dependent suppression of bax, a decrease in nuclear factor-kappaB and phospho-nuclear factor-kappaB, and transient loss of p53 levels. Coimmunoprecipitation studies suggest that the latter observation is mediated by an association between bcl-2 and phospho-mdm2. Bcl-2 silencing also led to p27 down-regulation and coimmunoprecipitation studies point to a role for bcl-2 in regulation of p27 localization/degradation. Bcl-2 silencing was also correlated with loss of cyclin D1a protein levels but not cyclin D1b levels. Coimmunoprecipitation studies indicate that bcl-2 may mediate its effects on cyclin D1a via interaction with p38 mitogen-activated protein kinase as well as a previously unreported interaction between bcl-2 and cyclin D1a.
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PMID:Silencing Bcl-2 in models of mantle cell lymphoma is associated with decreases in cyclin D1, nuclear factor-kappaB, p53, bax, and p27 levels. 1837 22

Hsp105alpha and Hsp105beta are major heat shock proteins in mammalian cells that belong to a subgroup of the HSP70 family, HSP105/110. Previously, we have shown that Hsp105alpha has opposite effects on stress-induced apoptosis depending on the cell type. However, it is not fully understood how Hsp105 regulates stress-induced apoptosis. In this study, we examined how Hsp105alpha and Hsp105beta regulate H2O2-induced apoptosis by using HeLa cells in which expression of Hsp105alpha or Hsp105beta was regulated using doxycycline. Overexpression of Hsp105alpha and Hsp105beta suppressed the activation of caspase-3 and caspase-9 by preventing the release of cytochrome c from mitochondria in H2O2-treated cells. Furthermore, both c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) were activated by treatment with H2O2, and the activation of both kinases was suppressed by overexpression of Hsp105alpha and Hsp105beta. However, H2O2-induced apoptosis was suppressed by treatment with a potent inhibitor of p38 MAPK, SB202190, but not a JNK inhibitor, SP600125. These findings suggest that Hsp105alpha and Hsp105beta suppress H2O2-induced apoptosis by suppression of p38 MAPK signaling, one of the essential pathways for apoptosis.
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PMID:Mammalian 105 kDa heat shock family proteins suppress hydrogen peroxide-induced apoptosis through a p38 MAPK-dependent mitochondrial pathway in HeLa cells. 1868 88

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits anti-carcinogenic effect. The results of present study showed that NFD inhibited the proliferation of breast cancer MDA-MB-231 cells through the induction of S-phase arrest and apoptosis. NFD-induced S-phase arrest was associated with a marked decrease in the protein expression of cyclin A, cyclin B, and cyclin-dependent kinase (Cdk)2. NFD-induced apoptosis was characterized by increase of sub-G1 population, phosphatidylserine (PS) externalization, and activation of caspases. Moreover, up-regulation of Bad and down-regulation of Bcl-2, Bcl-X(L), and survivin led to the loss of mitochondrial membrane potential (DeltaPsim), the release of cytochrome c and sequential activation of caspase-9 and caspase-3. NFD activated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK) in MDA-MB-231 cells. Inhibitors of JNK (SP600125) and ERK (PD98059), but not p38 MAPK (SB203580) suppressed NFD-induced S-phase arrest and apoptosis in MDA-MB-231 cells. Both SP600125 and PD98059 attenuated Bad up-regulation, and reversed down-regulation of Bcl-2, Bcl-X(L), survivin, cyclin A, cyclin B, and Cdk2 in NFD-treated cells. Taken together, our data show that JNK and ERK-signaling pathways play important roles in NFD-mediated S-phase arrest and apoptosis of MDA-MB-231 cells.
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PMID:Naphtho[1,2-b]furan-4,5-dione induces apoptosis and S-phase arrest of MDA-MB-231 cells through JNK and ERK signaling activation. 1974 39

Ultraviolet (UV) radiation is a major risk factor for the development of melanoma. Recent studies have reported that the intake of citrate-containing juices may reduce the risk of cancer. Thus, we investigated the effects of citrate on UVB-irradiated B16 murine melanoma cells. B16 cells had more evident apoptotic features with the combination of citrate/UVB than by citrate or UVB alone; cell death of HaCaT human keratinocytes was not observed with citrate/UVB. Western blot analysis demonstrated that citrate/UVB led to phosphorylation of the stress signaling proteins, such as c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Furthermore, citrate/UVB caused activation of caspase-9/-3 as well as cleavage of poly(ADP-ribose) polymerase (PARP). Correspondingly, cell cycle analysis showed that citrate/UVB clearly increased the sub-G0/G1 phase, which indicated apoptotic cell death of B16 cells. Therefore, our study has demonstrated that sub-lethal doses of citrate enhanced the apoptotic cell death of melanoma cells under UVB irradiation. From these results, we suggest that citrate might reduce the risk of developing melanoma induced by UVB.
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PMID:Enhanced effects of citrate on UVB-induced apoptosis of B16 melanoma cells. 2009 42

The aim of the present study is to elucidate the signalling components related to Naja nigricollis toxin--induced apoptosis in human leukaemia U937 cells. It was found that toxin--induced apoptotic cell death was attributed mainly to activation of p38 mitogen-activated protein kinase (MAPK), reactive oxygen species (ROS) generation and loss of mitochondrial membrane potential (deltapsim). Subsequent modulation of Bcl-2 family member and cytochrome c release accompanied with activation of caspase-9 and -3 were involved in the death of U937 cells. SB202190 (p38 MAPK inhibitor) and N-acetylcysteine (antioxidant) significantly attenuated toxin--induced cell death and loss of deltapsim, and completely abolished the production of ROS. In contrast to N-acetylcysteine, degradation of Bcl-2/Bcl-XL and mitochondrial localization of Bax were notably decreased by SB202190. Inhibitors of electron transport (rotenone and antimycin A) or inhibitor of mitochondrial permeability transition pore (cyclosporine A) reduced the effect of toxin- on ROS generation, loss of deltapsim and cytochrome c release. Noticeably, pre-treatment with N-acetylcysteine or rotenone eliminated markedly ROS accompanied with reduction in p38 MAPK activation. Taken together, these results suggest that the cytotoxicity of toxin- is initiated by p38-MAPK-mediated mitochondrial dysfunction followed by ROS production and activation of caspases, and that ROS further augments p38 MAPK activation and mitochondrial alteration.
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PMID:Reactive oxygen species and p38 mitogen-activated protein kinase induce apoptotic death of U937 cells in response to Naja nigricollis toxin-gamma. 2018 93

Curcumin, the principal curcuminoid of tumeric, has potent anticancer activity. To determine the mechanism of curcumin-induced cytotoxicity in prostate cancer cells, we exposed PC3 prostate carcinoma cells to 25 to 100 microM curcumin for 24 to 72 h. Curcumin treatment of PC3 cells caused time- and dose-dependent induction of apoptosis and depletion of cellular reduced glutathione (GSH). Exogenous GSH and its precursor N-acetyl-cysteine, but not ascorbic acid (AA) or ebselen, decreased curcumin accumulation in PC3 cells and also prevented curcumin-induced DNA fragmentation. The failure of AA and ebselen to protect PC3 cells from curcumin-induced apoptosis argued against the involvement of reactive oxygen species; rather, GSH-mediated inhibition of curcumin-induced cytotoxicity was due to reduced curcumin accumulation in PC3 cells. Curcumin-treated PC3 cells showed apoptosis-inducing cellular ceramide accumulation and activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase (JNK). Caspase-3, caspase-8, and caspase-9 were activated, and cytochrome c and apoptosis-inducing factor (AIF) were released from mitochondria following curcumin treatment. Interestingly, curcumin-induced apoptosis was not prevented by p38 MAPK, JNK, or caspase inhibition. We conclude that curcumin-induced cytotoxicity was due to cellular ceramide accumulation and damage to mitochondria that resulted in apoptosis mediated by AIF and other caspase-independent processes.
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PMID:Curcumin-induced apoptosis in PC3 prostate carcinoma cells is caspase-independent and involves cellular ceramide accumulation and damage to mitochondria. 2035 76

Histone deacetylase (HDAC) inhibitors have recently been reported to have possible reno-protective effects in the last few years. In this study, we found that tricostatin A (TSA), an HDAC inhibitor, prevented transforming growth factor beta1 (TGF-beta1)-induced apoptosis in cultured human renal proximal tubular epithelial cells (RPTECs). TGF-beta1-induced apoptosis via the activation of both caspase-8 and caspase-9 but did not activate the Fas receptor and did not alter Bcl-2 or Bax protein expression. TSA prevented TGF-beta1-induced apoptosis and the activation of caspase-8 and caspase-9 in RPTECs but did not inhibit the TGF-beta1-induced phosphorylation of Smad3 and p38 mitogen-activated protein kinase (MAPK). However, TSA inhibited the TGF-beta1-induced phosphorylation of extracellular signal regulated kinase (ERK), and the MAPK/ERK kinase inhibitor U0126, which specifically inhibits ERK, also prevented TGF-beta1-induced apoptosis. Our results show, for the first time, that TSA inhibits TGF-beta1-induced ERK activation and overrides pro-apoptotic signals like Smad3 and p38 in human RPTECs.
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PMID:Trichostatin a prevents TGF-beta1-induced apoptosis by inhibiting ERK activation in human renal tubular epithelial cells. 2055 9


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