UNIPROT:P10415 - FACTA Search

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Query: UNIPROT:P10415 (Bcl-2)
33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study investigates the relationship between the PKC-alpha and hepatic apoptosis during sepsis. Cecal ligation and puncture- (CLP) induced animal model of polymicrobial sepsis was used, with early and late sepsis referring to those animals sacrificed at 9 and 18 h, respectively, after CLP. The expressions of PKCalpha and Bcl-2 family proteins as well as poly(ADP-ribose) polymerase (PARP) cleavage were quantified to evaluate the possible factors involved in the hepatic cell death during sepsis. The apoptosis of hepatocytes under septic condition or hepatocytes treated with PKCalpha antisense was evaluated by gel electrophoresis and/or flow cytometry after Annexin-V-Fluos and propidium iodide staining. The results indicated that (1) the protein expression of membrane-associated PKCalpha was decreased at early (P < 0.05) and late (P < 0.01) sepsis; (2) the protein expressions of Bcl-2 and Bcl-xL were decreased, whereas Bax expression was increased at late sepsis; (3) the percentage of PARP cleavage was increased at early (P < 0.05) and late (P < 0.01) sepsis; (4) severe DNA fragmentation was observed at late sepsis; (5) the apoptotic cell population was increased at early and late sepsis; and (6) the percentage of apoptotic cell population in PKCalpha antisense-treated cells was significantly higher than that in untreated cells. These results suggest that inactivation of PKCalpha may play an important role in modulating hepatic apoptosis during sepsis and the apoptosis is closely associated with the alterations of Bcl-2 family proteins.
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PMID:The decrease of PKCalpha is associated with hepatic apoptosis at early and late phases of polymicrobial sepsis. 1122 Jun 41

JP-8 induces apoptosis in rat lung epithelial cells, primary mouse T lymphocytes, Jurkat T lymphoma cells, and U937 monocytic cells (Stoica et al., 2001). Here, we have observed a different mechanism of cytotoxicity in human keratinocytes grown in culture as well as when grafted onto nude mice. At lower levels of JP-8 (80 microg/ml; 1 x 10(-4) dilution), sufficient to induce apoptosis in other cell types, including lung epithelial cells (Stoica et al., 2001), no apoptosis was observed. At higher levels (>200 microg/ml; 2.5 x 10(-4) dilution), JP-8 is cytotoxic to both primary and immortalized human keratinocytes, as evidenced by the metabolism of calcein, as well as by morphological changes such as cell rounding and cell detachment. There was no evidence of activation of caspases-3, -7, or -8 either by enzyme activity or immunoblot analysis, and the stable expression of a dominant-negative inhibitor of apoptosis (FADD-DN) did not increase the survival of keratinocytes to JP-8. The pattern of poly(ADP-ribose) polymerase (PARP) cleavage was also characteristic of necrosis. PARP has been also been implicated in necrosis via its ability to lower levels of ATP in damaged cells. However, fibroblasts derived from PARP-/- mice underwent necrotic cell death similar to those derived from PARP+/+ mice, indicating that the effects of JP-8 are independent of PARP. Immunoblot analysis further revealed that exposure of keratinocytes to the toxic higher levels of JP-8 markedly downregulates the expression of the prosurvival members of the Bcl-2 family, Bcl-2 and Bcl-x(L), and upregulates the expression of antisurvival members of this family, including Bad and Bak. Bcl-2 and Bcl-x(L) have been shown to preserve mitochondrial integrity and suppress cell death. In contrast, Bak and Bad both promote cell death by alteration of the mitochondrial membrane potential, in part by heterodimerization with and inactivation of Bcl-2 and Bcl-x(L), and either inducing necrosis or activating a downstream caspase program. High intrinsic levels of Bcl-2 and Bcl-x(L) may prevent apoptotic death of keratinocytes at lower levels of JP-8, while perturbation of the balance between pro- and antiapoptotic Bcl-2 family members at higher levels may ultimately play a role in necrotic cell death in human keratinocytes. Finally, when human keratinocytes were grafted to form a human epidermis on nude mice, treatment of these grafts with JP-8 revealed cytotoxicity and altered histology in vivo.
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PMID:Mechanisms of JP-8 jet fuel cell toxicity. II. Induction of necrosis in skin fibroblasts and keratinocytes and modulation of levels of Bcl-2 family members. 1122 86

Garcinol, a polyisoprenylated benzophenone, was purified from Garcinia indica fruit rind. The effects of garcinol and curcumin on cell viability in human leukemia HL-60 cells were investigated. Garcinol and curcumin displayed strong growth inhibitory effects against human leukemia HL-60 cells, with estimated IC(50) values of 9.42 and 19.5 microM, respectively. Garcinol was able to induce apoptosis in a concentration- and time-dependent manner; however, curcumin was less effective. Treatment with garcinol caused induction of caspase-3/CPP32 activity in a dose- and time-dependent manner, but not caspase-1 activity, and induced the degradation of poly(ADP-ribose) polymerase (PARP). Pretreatment with caspase-3 inhibitor inhibited garcinol-induced DNA fragmentation. Treatment with garcinol (20 microM) caused a rapid loss of mitochondrial transmembrane potential, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. The cleavage of D4-GDI, an abundant hematopoietic cell GDP dissociation inhibitor for the Ras-related Rho family GTPases, occurred simultaneously with the activation of caspase-3 but preceded DNA fragmentation and the morphological changes associated with apoptotic cell death. Of these, Bcl-2, Bad, and Bax were studied. The level of expression of Bcl-2 slightly decreased, while the levels of Bad and Bax were dramatically increased in cells treated with garcinol. These results indicate that garcinol allows caspase-activated deoxyribonuclease to enter the nucleus and degrade chromosomal DNA and induces DFF-45 (DNA fragmentation factor) degradation. It is suggested that garcinol-induced apoptosis is triggered by the release of cytochrome c into the cytosol, procaspase-9 processing, activation of caspase-3 and caspase-2, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by garcinol may provide a pivotal mechanism for its cancer chemopreventive action.
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PMID:Induction of apoptosis by garcinol and curcumin through cytochrome c release and activation of caspases in human leukemia HL-60 cells. 1131 81

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, Apo-2L) is a recently characterized member of the family of programmed cell death-inducing ligands that includes TNF-alpha and CD95L (FasL). It is well known that TRAIL binds to the death signaling receptors, DR4 and DR5, and initiates the TRAIL death pathway. Activation of this pathway, mediated through a caspase cascade, causes apoptosis. In this study, we hypothesized that oxidative stress facilitates TRAIL-induced apoptosis by promoting caspase activity through cytochrome c release from mitochondria. Human colorectal carcinoma CX-1 cells were treated with various concentrations of TRAIL (12.5-200 ng/ml) and/or sodium nitroprusside (SNP; 0.03-1 mM) for 12 h. SNP, a nitric oxide donor, which had little toxic effect by itself, enhanced TRAIL-induced cytotoxicity. For example, TRAIL-induced apoptosis (200 ng/ml) was increased by a factor of 2.5-fold in the presence of 1 mM SNP. The combined treatment also caused an increase in cytochrome c release, caspase-3 activity, and PARP cleavage. Overexpression of Bcl-2 completely blocked the SNP-promoting effects, but only moderately inhibited TRAIL-induced apoptosis. Similar results were observed in the presence of hydrogen peroxide or peroxynitrite. Taken together, the present studies suggest that SNP enhances TRAIL-induced cytotoxicity by facilitating the mitochondria-mediated caspase signal transduction pathway.
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PMID:Sodium nitroprusside enhances TRAIL-induced apoptosis via a mitochondria-dependent pathway in human colorectal carcinoma CX-1 cells. 1131 91

Degradation of several intracellular proteins involved in cell cycle control and tumour growth is regulated by the ubiquitin-dependent multicatalytic protease complex (proteasome). We report that proteasome inhibitor Z-Ile-Glu(OtBu)-Ala-Leucinal (PSI) was cytotoxic on most human myeloid leukaemia cell lines at IC50 doses ranging from 5 to 25 nmol/l. Additionally, PSI pre-treatment enhanced cytotoxicity by taxol and cisplatinum. PSI was more active on leukaemic than on normal CD34(+) bone marrow progenitors because the 50% growth inhibition of colony-forming unit granulocyte macrophage (CFU-GM) from cases of chronic myelogenous leukaemia (CML) and normal subjects was achieved by 15 nmol/l and 50 nmol/l PSI respectively. PSI killed cells by apoptosis as revealed by ultrastructural changes, nuclear DNA fragmentation, cleavage of poly (ADP-ribose) polymerase (PARP) and of beta-catenin, and was antagonized by ectopic expression of Bcl-2 but not by inactivating mutations of p53. This event was associated with a slight accumulation of Bcl-2, a decrease of Bax but no changes in Bcl-X(L) protein expression at any time point. In Ph(+) cell lines BCR-ABL protein was only down-regulated after 48 h of treatment with 10 nmol/l PSI. Altogether, these results indicate that PSI, alone or in association with other cytotoxic agents, has anti-tumour activity against myeloid malignancies and is more effective on leukaemic than on normal haematopoietic progenitor cells.
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PMID:The apoptogenic response of human myeloid leukaemia cell lines and of normal and malignant haematopoietic progenitor cells to the proteasome inhibitor PSI. 1132 92

The ability of ricin, a type II ribosome-inactivating protein, to induce hepatoma cell (BEL7404) to apoptosis in vitro was examined by fluorescence microscopy, flow cytometry, and DNA fragmentation assay. As a Bcl-2 lacking model, BEL7404 bore unique advantage to study the effect of over-expressing Bcl-2 on the apoptosis induced by the inhibitor of protein synthesis. By establishing a Bcl-2 over-expressing cell line (BEL7404/ Bcl-2), we found that Bcl-2 could promote the survival of the hepatoma cell against ricin insult. The ricin-induced apoptosis of BEL7404 was accompanied by increased expression of Bak and decreased levels of Bcl-xl and Bax. Caspases and PARP cleavage activity were found to be implicated in the death process. Through the inhibitor tests, our results excluded the participation of calcium-dependent proteases or protein kinase C in the apoptotic process induced by ricin, though an elevation of intracellular calcium did occur as an immediate response to ricin treatment. Cycloheximide, another protein synthesis inhibitor, did synergistically enhance rather than inhibit the cytotoxicity of ricin to hepatoma cell BEL7404. Actually, cycloheximide alone was able to induce hepatoma cell BEL7404 to death that could also be inhibited by over-expressing Bcl-2. The elevation of apoptotic protein Bak was discussed to challenge the notion that ricin exerted its cytotoxicity through nonspecific inhibition of all the de novo protein synthesis.
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PMID:An insight into the mechanism of cytotoxicity of ricin to hepatoma cell: roles of Bcl-2 family proteins, caspases, Ca(2+)-dependent proteases and protein kinase C. 1132 13

The impact of dysregulation of the cyclin-dependent kinase inhibitor p21WAF1/CIP1/MDA6 has been examined in U937 human monocytic leukemia cells in relation to cell cycle arrest and differentiation following treatment with the histone deacetylase inhibitor sodium butyrate (SB). Cells stably transfected with a p21WAF1/CIP1/MDA6 antisense construct, in marked contrast to their wild-type counterparts, failed to up-regulate p21WAF1/CIP1/MDA6, undergo G1 arrest, or express the maturation marker CD11b when exposed to 1 or 3 mM SB. However, antisense-expressing cells were significantly more susceptible to SB-mediated mitochondrial injury and apoptosis, manifested by increased cytosolic translocation of cytochrome c, activation of pro-caspase 3, and degradation of PARP. Dysregulation of p21WAF1/CIP1/MDA6 did not modify the extent of SB-induced histone acetylation, but did result in cleavage of p27KIP1, Bcl-2 and pRb, as well as diminished levels of full-length underphosphorylated pRb. Finally, dysregulation of p21WAF1/CIP1/MDA6 did not modify SB-mediated down-regulation of E2F-1 or c-Myc, but was associated with enhanced down-regulation of cyclins D1 and E. Together, these findings indicate that in U937 leukemia cells, p21WAF1/CIP1/MDA6 plays a critical functional role in SB-mediated G1 arrest and maturation, and suggest that cells displaying dysregulation of this CDKI respond to SB by engaging a default apoptotic program.
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PMID:Evidence of a functional role for the cyclin-dependent kinase-inhibitor p21WAF1/CIP1/MDA6 in promoting differentiation and preventing mitochondrial dysfunction and apoptosis induced by sodium butyrate in human myelomonocytic leukemia cells (U937). 1140 41

Prostate cancer is one of the most common cancers in men and it is the second leading cause of cancer related death in men in the United States. Recent dietary and epidemiological studies have suggested the benefit of dietary intake of fruits and vegetables in lowering the incidence of prostate cancer. A diet rich in fruits and vegetables provides phytochemicals, particularly indole-3-carbinol (I3C), which may be responsible for the prevention of many types of cancer, including hormone-related cancers such as prostate. Studies to elucidate the role and the molecular mechanism(s) of action of I3C in prostate cancer, however, have not been conducted. In the current study, we investigated whether I3C had any effect against prostate cancer cells and, if so, attempts were made to identify the potential molecular mechanism(s) by which I3C elicits its biological effects on prostate cancer cells. Here we report for the first time that I3C inhibits the growth of PC-3 prostate cancer cells. Induction of G1 cell cycle arrest was also observed in PC-3 cells treated with I3C, which may be due to the observed effects of I3C in the up-regulation of p21(WAF1) and p27(Kip1) CDK inhibitors, followed by their association with cyclin D1 and E and down-regulation of CDK6 protein kinase levels and activity. The induction of p21(WAF1) appears to be transcriptionally upregulated and independent of the p53 responsive element. In addition, I3C inhibited the hyperpohosphorylation of the Retinoblastoma (Rb) protein in PC-3 cells. Induction of apoptosis was also observed in this cell line when treated with I3C, as measured by DNA laddering and poly (ADP-ribose) polymersae (PARP) cleavage. We also found an up-regulation of Bax, and down-regulation of Bcl-2 in I3C-treated cells. These effects may also be mediated by the down-regulation of NF-kappaB observed in I3C treated PC-3 cells. From these results, we conclude that I3C inhibits the growth of PC-3 prostate cancer cells by inducing G1 cell cycle arrest leading to apoptosis, and regulates the expression of apoptosis-related genes. These findings suggest that I3C may be an effective chemopreventive or therapeutic agent against prostate cancer.
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PMID:Indole-3-carbinol (I3C) induced cell growth inhibition, G1 cell cycle arrest and apoptosis in prostate cancer cells. 1142 Jul 5

We describe two pathways by which the vesicating agent sulfur mustard (HD) may cause basal cell death and detachment: induction of terminal differentiation and apoptosis. Following treatment of normal human epidermal keratinocytes (NHEK) with 10 or 100 microM HD, the differentiation-specific keratin pair K1/K10 was induced and the cornified envelope precursor protein, involucrin, was cross-linked by epidermal transglutaminase. Fibronectin levels were reduced in a time- and dose-dependent manner. The rapid increase in p53 and decrease in Bcl-2 levels was consistent not only with epidermal differentiation but with apoptosis as well. Further examination of biochemical markers of apoptosis following treatment of either NHEK or human papillomavirus (HPV)-immortalized keratinocytes revealed a burst of poly(ADP-ribose) synthesis, specific cleavage of poly(ADP-ribose)polymerase (PARP) in vivo and in vitro into characteristic 89 and 24 kDa fragments, processing of caspase-3 into its active form and the formation of DNA ladders. The intracellular calcium chelator BAPTA suppressed the differentiation markers, whereas antisense oligonucleotides and chemical inhibitors specific for calmodulin blocked both markers of differentiation and apoptosis. Modulation of p53 levels utilizing retroviral constructs expressing the E6, E7 or E6 + E7 genes of HPV-16 revealed that HD-induced apoptosis was partially p53-dependent. Finally, immortalized fibroblasts derived from PARP -/- 'knockout mice' were exquisitely sensitive to HD-induced apoptosis. These cells became HD resistant when wild-type PARP was stably expressed in these cells. These results indicate that HD exerts its effects via calmodulin, 3 and PARP-sensitive pathways.
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PMID:Calmodulin, poly(ADP-ribose)polymerase and p53 are targets for modulating the effects of sulfur mustard. 1142 42

Busulfan is an alkylating agent currently used in the myeloablative conditioning regimen before stem cell transplantation. Its mechanism of action is not fully understood, nor the reason for its narrow therapeutic window. We studied the pharmacodynamics of busulfan in an in vitro cell line model, allowing us to evaluate the effects of various doses and exposure times on clonogeneic capacity, proliferation and apoptosis. Cells were incubated with busulfan in concentrations ranging from 10 to 100 microg/ml for 2, 4 or 8 h, then washed and cultured in busulfan-free medium for 72 h. Area under the concentration-time curve (AUC) was estimated by using the trapezoidal rule from different concentrations and times of incubation. In all assays busulfan affected the cells in an AUC-dependent manner. Induced changes in the biological parameters studied appeared at different time points after exposure to busulfan stopped. Thus, the decrease in proliferation and clonogenic capacity preceded cell cycle arrest in G2 phase and development of apoptosis, implying that apoptosis is a secondary event to interruption of vital metabolic processes. Biochemically, apoptotic changes were typical for chemotherapy-induced apoptosis with caspase activation, cleavage of Bcl-2 and PARP proteins, while cleavage of actin was not observed. Cells were rescued from apoptosis with a general caspase inhibitor ZVAD-fmk, but not with granulocyte colony-stimulating factor (G-CSF). Our results add new information about busulfan pharmacodynamics and mechanisms underlying the cytotoxic effect of the drug.
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PMID:The pharmacodynamic effect of busulfan in the P39 myeloid cell line in vitro. 1148 May 66

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