Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of Taxol-induced apoptosis was investigated in MCF-7 human breast carcinoma cells. Taxol-induced apoptosis was associated with phosphorylation of both c-Raf-1 and Bcl-2 and activation of ERK and JNK MAP kinases. The serine protease inhibitor N-tosyl-L-phenylalanine chloromethyl ketone (TPCK) effectively blocked apoptosis, but N-p-tosyl-L-lysine chloromethyl ketone (TLCK), another serine protease inhibitor, was without effect. TPCK treatment also prevented phosphorylation of c-Raf-1 and Bcl-2 in response to Taxol treatment. The serine protease inhibitor did not alter JNK activity, but it enhanced Taxol-induced activation of ERK1/2. Treatment of cells with the inhibitor of MEK activation, PD98059, prevented Taxol-induced ERK activation both in the presence and absence of TPCK, but did not influence survival of either Taxol- or Taxol plus TPCK-treated cells. In addition, PD98059 had no effect on c-Raf-1 or Bcl-2 phosphorylation. Thus, while the Taxol-induced phosphorylations of c-Raf-1 and Bcl-2 proteins appear to be coupled, these events can be disassociated from ERK1/2 activation. In summary, these findings suggest that phosphorylation of c-Raf-1 and Bcl-2, but not ERK1/2, are important signaling events in Taxol-induced apoptosis of MCF-7 breast cancer cells and that a TPCK inhibitable protease(s) is required for these processes.
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PMID:Serine protease inhibitor TPCK prevents Taxol-induced cell death and blocks c-Raf-1 and Bcl-2 phosphorylation in human breast carcinoma cells. 1037 21

We have shown that reoxygenation of hypoxic rat kidney proximaltubule cells leads to apoptosis. This is mediated by translocation ofBax from the cytosol to mitochondria, accompanied by release ofmitochondrial cytochrome c (cyt.c). The present studyhas examined the proteolytic mechanisms responsible for apoptosisduring hypoxia-reoxygenation. Caspases were activated duringhypoxia, as shown by cleavage of fluorogenic peptide substrates. By5 h caspase-3-like activity to cleave carbobenzoxy-Asp-Glu-Val-Asp-7-amino-4-trifluoromethyl coumarin was increased approx. 30-fold. Thiswas accompanied by specific processing of pro-caspase-3, -8 and -9 intoactive forms. Caspase activation during hypoxia was blocked bycarbobenzoxy-Val-Ala-Asp-fluoromethyl ketone and overexpression of Bcl-2. Of particular interest, caspase activation was also suppressed bythe chymotryptic inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and Ala-Pro-Phe chloromethyl ketone (APF),and the general serine protease inhibitor 4-(2-aminoethyl)benzenesulphonyl fluoride. Inhibition of caspase activationby these compounds resulted in arrest of apoptosis. On the other hand,the serine protease inhibitors did not prevent release of mitochondrialcyt.c during hypoxia, suggesting that these compounds blockeda critical step in post-mitochondrial caspase activation. Furtherstudies using an in vitro reconstitution model showedthat cyt. c/dATP stimulated caspase-9 processing and downstreamcaspase activation were significantly suppressed in the presence ofTPCK and APF. Based on these results, we speculate that serineproteases may be involved in post-mitochondrial apoptotic events thatlead to activation of the initiator, caspase-9.
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PMID:Serine protease inhibitors suppress cytochrome c-mediatedcaspase-9 activation and apoptosis during hypoxia-reoxygenation. 1076 69

Cell death processes are progressively inactivated during malignant development, in part by loss of tumor suppressors that can promote cell death. The Bin1 gene encodes a nucleocytosolic adaptor protein with tumor suppressor properties, initially identified through its ability to interact with and inhibit malignant transformation by c-Myc and other oncogenes. Bin1 is frequently missing or functionally inactivated in breast and prostate cancers and in melanoma. In this study, we show that Bin1 engages a caspase-independent cell death process similar to type II apoptosis, characterized by cell shrinkage, substratum detachment, vacuolated cytoplasm, and DNA degradation. Cell death induction was relieved by mutation of the BAR domain, a putative effector domain, or by a missplicing event that occurs in melanoma and inactivates suppressor activity. Cells in all phases of the cell cycle were susceptible to death and p53 and Rb were dispensable. Notably, Bin1 did not activate caspases and the broad spectrum caspase inhibitor ZVAD.fmk did not block cell death. Consistent with the lack of caspase involvement, dying cells lacked nucleosomal DNA cleavage and nuclear lamina degradation. Moreover, neither Bcl-2 or dominant inhibition of the Fas pathway had any effect. In previous work, we showed that Bin1 could not suppress cell transformation by SV40 large T antigen. Consistent with this finding, we observed that T antigen suppressed the death program engaged by Bin1. This observation was interesting in light of emerging evidence that T antigen has roles in cell immortalization and human cell transformation beyond Rb and p53 inactivation. In support of a link to c-Myc-induced death processes, AEBSF, a serine protease inhibitor that inhibits apoptosis by c-Myc, potently suppressed DNA degradation by Bin1. Our findings suggest that the tumor suppressor activity of Bin1 reflects engagement of a unique cell death program. We propose that loss of Bin1 may promote malignancy by blunting death penalties associated with oncogene activation.
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PMID:The c-Myc-interacting adaptor protein Bin1 activates a caspase-independent cell death program. 1103 17

Cross-linking of cell surface Fas molecules by Fas ligand or by agonistic anti-Fas Abs induces cell death by apoptosis. We found that a serine protease inhibitor, N-tosyl-L-lysine chloromethyl ketone (TLCK), dramatically enhances Fas-mediated apoptosis in the human T cell line Jurkat and in various B cell lines resistant to Fas-mediated apoptosis. The enhancing effect of TLCK is specific to Fas-induced cell death, with no effect seen on TNF-alpha or TNF-related apoptosis-inducing ligand-induced apoptosis. TLCK treatment had no effect on Fas expression levels on the cell surface, and neither promoted death-inducing signaling complex formation nor decreased expression levels of cellular inhibitors of apoptosis (FLICE inhibitory protein, X chromosome-linked inhibitor of apoptosis, and Bcl-2). Activation of the Fas-mediated apoptotic pathway by anti-Fas Ab is accompanied by aggregation of Fas molecules to form oligomers that are stable to boiling in SDS and beta-ME. Fas aggregation is often considered to be required for Fas-mediated apoptosis. However, sensitization of cells to Fas-mediated apoptosis by TLCK or other agents (cycloheximide, protein kinase C inhibitors) causes less Fas aggregation during the apoptotic process compared with that in nonsensitized cells. These results show that Fas aggregation and Fas-mediated apoptosis are not directly correlated and may even be inversely correlated.
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PMID:Fas aggregation does not correlate with Fas-mediated apoptosis. 1141 35

Tissue factor pathway inhibitor-2 (TFPI-2) is a 32 kDa serine protease inhibitor found at high levels in extracellular matrix. Recombinant human TFPI-2 has recently been shown to be a strong inhibitor of trypsin, plasmin, plasma kallikrein, and factor XIa amidolytic activity. Earlier studies in our laboratory showed that the expression of TFPI-2 is lost during tumor progression in human gliomas. We stably transfected this protease inhibitor in multiform glioblastoma cell line (SNB-19) and in low-grade glioma cell line (Hs683) in sense and antisense orientation respectively. This confirmed that the upregulation/down-regulation of TFPI-2 plays a significant role in the invasive behavior of human gliomas both in vitro and in vivo models. Collectively, these results suggested an idea to determine whether TFPI-2 is necessary for cell survival and inhibition of tumor formation in nude mice, due to apoptosis of intracerebrally injected SNB-19 cells. In the present study we determined p-ERK levels and found that they are decreased in TFPI-2 over-expressed clones (SNB-19) and increased in TFPI-2 down-regulated clones (Hs683). We also checked the levels of BAX/BCl-2, caspases (for e.g., 9, 7, 3, 8), PARP, cytochrome-c and Apaf-1. Moreover, the increase of apoptosis in vitro is associated with increased and decreased expression of apoptotic protein BAX in sense clones (SNB-19) and antisense clones (Hs683) respectively, when compared to controls and vice versa with Bcl-2 the anti-apoptotic protein. Caspases (9, 7 and 3), cytochrome-c, Apaf-1 and PARP levels are increased in SNB-19 and decreased in Hs683. Caspase 8 was not expressed in either cell line. Caspases 9 and 3 activity assay revealed higher activity in sense clones (SNB-19) but lesser in antisense clones (Hs683) compared to controls. This is the first report of TFPI-2 playing a novel role in cell survival in human gliomas.
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PMID:A novel role of tissue factor pathway inhibitor-2 in apoptosis of malignant human gliomas. 1149 41

In L929sAhFas cells, tumor necrosis factor (TNF) leads to necrotic cell death, whereas agonistic anti-Fas antibodies elicit apoptotic cell death. Apoptosis, but not necrosis, is correlated with a rapid externalization of phosphatidylserine and the appearance of a hypoploid population. During necrosis no cytosolic and organelle-associated active caspase-3 and -7 fragments are detectable. The necrotic process does not involve proteolytic generation of truncated Bid; moreover, no mitochondrial release of cytochrome c is observed. Bcl-2 overexpression slows down the onset of necrotic cell death. In the case of apoptosis, active caspases are released to the culture supernatant, coinciding with the release of lactate dehydrogenase. Following necrosis, mainly unprocessed forms of caspases are released. Both TNF-induced necrosis and necrosis induced by anti-Fas in the presence of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone are prevented by the serine protease inhibitor N-tosyl-L-phenylalanine chloromethylketone and the oxygen radical scavenger butylated hydroxyanisole, while Fas-induced apoptosis is not affected.
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PMID:Death receptor-induced apoptotic and necrotic cell death: differential role of caspases and mitochondria. 1152 36

The NFkappaB transcription factors can both promote cell survival and induce apoptosis depending on cell type and context. Neuroblastoma (NB) cells display two predominant culture phenotypes identified as N- and S-types. Malignant S-type cells express neither high levels of MYCN nor Bcl-2, suggesting that other survival mechanisms are important. We characterized NFkappaB activity in S-type cells and determined its role in their survival. S-type lines (SH-EP1 and SK-N-AS) were treated with pyrrolidine dithiocarbamate (PDTC), a NFkappaB inhibitor, or l-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK), a serine protease inhibitor that blocks IkappaBalpha degradation. Both agents induced cell death, suggesting that constitutive NFkappaB activity is required for survival. The transient expression of a super-repressor IkappaBalpha mutant killed S-type cells. The inhibition of NFkappaB produced an apoptotic response characterized by the collapse of the mitochondrial transmembrane electrochemical gradient, caspase-9 activation, and apoptotic DNA changes. Constitutive NFkappaB DNA binding activity specifically involving p65 and p50 was demonstrated in S- but not N-type cells by electromobility supershift and gene reporter assays. This study demonstrates a role for NFkappaB in the survival of S-type NB tumor cells and suggests that NFkappaB activity and function differ according to NB tumor cell phenotype.
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PMID:Constitutively active NFkappa B is required for the survival of S-type neuroblastoma. 1219 14

Maspin, a serine protease inhibitor (serpin), can suppress tumor growth and metastasis in vivo and tumor cell motility and invasion in vitro. This may occur through maspin-mediated inhibition of pericellular proteolysis. In a recent report, we provided evidence that maspin may also suppress tumor progression by enhancing cellular sensitivity to apoptotic stimuli. To our knowledge, maspin is the only proapoptotic serpin among all of the serpins implicated thus far in apoptosis regulation. The goal of the present study is to identify the specific target molecule(s), the modification of which by maspin renders tumor cells sensitive to chemotherapeutic agents. Our cellular, molecular, and biochemical studies demonstrate an essential role of Bax in the proapoptotic effect of maspin. First, Bax was up-regulated in maspin-transfected prostate and breast tumor cells, whereas the levels of other Bcl-2 family members including Bcl-2, Bcl-xl, and Bak remained unchanged. Second, on apoptosis induction, a greater amount of Bax was translocated from cytosol to mitochondria in maspin-transfected cells. After treatment with a Bax-silencing small interfering RNA, maspin-transfected cells became significantly more resistant to drug-induced apoptosis. Consistently, the release of cytochrome c and Smac/DIABLO from mitochondria was more responsive to apoptosis stimuli in maspin-transfected cells than in the mock-transfected cells. Third, the apoptosis induction of maspin-transfected cells was associated with increased activation of both caspase-8 and caspase-9. However, a caspase-9-specific inhibitor blocked the sensitization effect of maspin in a dose-dependent and time-dependent manner, demonstrating a rate-limiting role for caspase-9. In line with the central role of the Bax-mediated mitochondrial apoptotic pathway, maspin sensitized the apoptotic response of breast and prostate carcinoma cells to various drugs, ranging from death ligands to endoplasmic reticulum stress. The link between maspin and Bax up-regulation explains the loss of maspin-expressing tumor cells in invasive breast and prostate carcinomas. Our data reveal a novel mechanism for tumor suppressive maspin and suggest that maspin may be used as a modifier for apoptosis-based cancer therapy.
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PMID:Bax mediates the apoptosis-sensitizing effect of maspin. 1499 30

Complement activation augments myocardial cell injury and apoptosis during ischemia/reperfusion (I/R), whereas complement system inhibition with C1 inhibitor (C1INH), a serine protease inhibitor, exerts markedly cardioprotective effects. Our recent data demonstrate that C1INH prevents vascular endothelial cell apoptosis and a "modified" form of the reactive center loop-cleaved, inactive C1INH (iC1INH) plays an anti-inflammatory role in endotoxin shock. The aim of this study was to determine whether C1INH protects against myocardial cell injury via an anti-apoptotic activity or anti-inflammatory effect. In a rat model of acute myocardial infarction (AMI) induced by I/R, administration of C1INH protected against cardiomyocytic apoptosis via normalization of ratio of the Bcl-2/Bax expression in the myocardial infarct area. C1INH improved parameters of cardiac function and hemodynamics and reduced myocardial infarct size (MIS). In addition, myocardial and blood myeloperoxidase (MPO) activity, a marker of neutrophil infiltration, was decreased by treatment of C1INH. In cultured H9c2 rat cardiomyocytic cells, C1INH blocked hypoxia/reoxygenation-induced apoptosis in the absence of sera associated with inhibition of cytochrome c translocation and suppression of caspase-3 activation. The proportion of Bcl-2/Bax expression induced by hypoxia/reoxygenation was reversed by C1INH. Importantly, iC1INH also revealed these similar effects, indicating that C1INH has a direct anti-apoptotic activity. Therefore, these studies support the hypothesis that C1INH, in addition to inhibition of activation of the complement and contact systems, improves outcome in I/R-mediated myocardial cell injury via an anti-apoptotic activity independent of serine protease inhibitory activity.
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PMID:Anti-apoptotic role for C1 inhibitor in ischemia/reperfusion-induced myocardial cell injury. 1694 49

Griseofulvin (GF), an oral antifungal agent, has been shown to exert antitumorigenesis effect through G2/M cell cycle arrest in colon cancer cells. But the underlying mechanisms remained obscure. The purpose of this study is to test the cytotoxic effect of GF on HL-60 and HT-29 cells and elucidate its underlying molecular pathways. Dose-dependent and time-course studies by flow cytometry demonstrated that 30 to 60 microM GF significantly induced G2/M arrest and to a less extend, apoptosis, in HL-60 cells. In contrast, only G2/M arrest was observed in HT-29 cells under similar condition. Pretreatment of 30 microM TPCK, a serine protease inhibitor, completely reversed GF-induced G2/M cell cycle arrest and apoptosis in HL-60 cells but not in HT-29 cells. The GF-induced G2/M arrest in HL-60 cells is reversible. Using EMSA and super-shift analysis, we demonstrated that GF stimulated NF-kappaB binding activity in HL-60 cells, which was completely inhibited by pretreatment of TPCK. Treatment of HL-60 with 30 microM GF activated JNK but not ERK or p38 MAPK and subsequently resulted in phosphorylation of Bcl-2. Pretreatment of TPCK to HL-60 cells blocked the GF-induced Bcl-2 phosphorylation but not JNK activation. Time course study demonstrated that activation of cdc-2 kinase activity by GF correlated with Bcl-2 phosphorylation. Taken together, our results suggest that activation of NF-kappaB pathway with cdc-2 activation and phosphorylation of Bcl-2 might be involved in G2/M cell cycle arrest in HL-60 cells.
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PMID:NF-kappaB pathway is involved in griseofulvin-induced G2/M arrest and apoptosis in HL-60 cells. 1722 69


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