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)

Oxidative stress induced by reactive oxygen intermediates often causes cell death via apoptosis, which is regulated by many functional genes and their protein products. The evolutionarily conserved protein Bcl-2 blocks apoptosis induced by a wide array of death signals. Despite extensive research, the molecular milieu that characterizes the anti-apoptotic function of Bcl-2 has not been fully clarified. In this work, we have investigated the role of bcl-2 in protecting against oxidative death induced by H(2)O(2) in cultured rat pheochromocytoma PC12 cells. Transfection with the bcl-2 gene rescued PC12 cells from apoptotic death caused by H(2)O(2). Addition of NF-kappaB inhibitors such as pyrrolidine dithiocarbamate and N-tosyl-l-phenylalanine chloromethyl ketone to the medium aggravated oxidative cell death. PC12 cells overexpressing bcl-2 exhibited relatively high constitutive DNA binding and transcriptional activities of NF-kappaB compared with vector-transfected control cells. Western blot analysis and immunocytochemistry revealed that bcl-2-transfected PC12 cells retained a higher level of p65 (the functionally active subunit of NF-kappaB) in the nucleus compared with vector-transfected controls. In addition, sustained activation of ERK1/2 (upstream of NF-kappaB) was observed in bcl-2-overexpressing cells. In contrast, the cytoplasmic inhibitor IkappaBalpha was present in lower amounts in cells overexpressing bcl-2. The ectopic expression of bcl-2 increased the cellular glutathione level and gamma-glutamylcysteine ligase expression, which were attenuated by NF-kappaB inhibitors. These results suggest that NF-kappaB plays a role in bcl-2-mediated protection against H(2)O(2)-induced apoptosis in PC12 cells through augmentation of antioxidant capacity.
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PMID:Bcl-2 attenuation of oxidative cell death is associated with up-regulation of gamma-glutamylcysteine ligase via constitutive NF-kappaB activation. 1520 16

A substantial body of data indicates that reactive oxygen intermediates (ROIs) are implicated in pathogenesis of diverse human diseases. Oxidative stress induced by ROIs often causes cell death via apoptosis that is regulated by a plenty of functional genes and their protein products. Bcl-2 is one such protein that blocks apoptosis induced by various death stimuli. In spite of extensive research, the molecular mechanisms underlying antiapoptotic function of Bcl-2 are not fully clarified. In the present work, we have investigated the role of bcl-2 in protecting against beta-amyloid (Abeta)-induced oxidative death in rat pheochromocytoma (PC12) cells. Transfection with the antiapoptotic bcl-2 gene rescued PC12 cells from apoptotic death induced by Abeta. Addition of an NF-kappaB inhibitor, such as pyrrolidine dithiocarbamate or N-tosyl-l-phenylalanine chloromethyl ketone, to the media aggravated Abeta-induced PC12 cell death. PC12 cells overexpressing bcl-2 exhibited higher levels of constitutively activated NF-kappaB compared with vector-transfected controls, which appear to be mediated by the elevated activation of Akt/protein kinase B. The ectopic expression of bcl-2 enhanced both the expression and the activity of catalase, which were attenuated by NF-kappaB blockers. These results suggest that NF-kappaB plays a role in bcl-2-mediated protection against Abeta-induced apoptosis in PC12 cells through augmentation of cellular antioxidant capacity.
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PMID:Bcl-2 protects against Abeta(25-35)-induced oxidative PC12 cell death by potentiation of antioxidant capacity. 1524 Jan 30

Neutrophil apoptosis is delayed under trauma and/or sepsis injury conditions. The molecular mechanism for the delay in apoptosis has not been well defined. We investigated whether activation of phosphatidyl inositol 3-kinase (PI3-kinase)/PKB signaling pathway contributes to the delay in neutrophil apoptosis with thermal injury. Rats were subjected to burns (30% total body surface area, 98 degrees C for 10 s), and euthanized 24 h later. Blood neutrophils were isolated with the use of Ficoll gradient centrifugation and cultured for the indicated time periods. Apoptosis was determined using annexin V and PI labeling and flow cytometry. NF-kappaB activation was examined using gel mobility shift assay and confocal microscopy. Expression levels of inhibitory apoptosis proteins (IAPs), including cellular IAP1 (cIAP1), cIAP2, X-linked IAP (XIAP), and survivin, and Bcl-2 family members such as Bcl-xl and Bad, were determined by Western blot analysis and/or RT-PCR, real-time PCR. The results showed that in culture, the decrease in apoptosis of neutrophils from thermally injured rats was prevented in the presence of PI3-kinase inhibitors wortmannin and LY-294002. There was upregulation of PKB and Bad phosphorylation and NF-kappaB activation in N-formyl-l-methionyl-l-leucyl-l-phenylalanine-stimulated neutrophils from thermally injured rats compared with the sham injured group. Increased Bad phosphorylation and NF-kappaB activation were also attenuated by wortmannin. Bcl-xl expression in neutrophils was upregulated with thermal injury and inhibited in the presence of wortmannin. However, the expression of IAP family members was neither affected by thermal injury nor inhibited by wortmannin. These data suggest that the delay in neutrophil apoptosis with thermal injury is partly caused by activation of PI3-kinase/PKB signaling and NF-kappaB, which appeared to be related to the increased Bcl-xl expression and phosphorylation of Bad, but not IAP expression.
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PMID:Activation of PI3-kinase/PKB contributes to delay in neutrophil apoptosis after thermal injury. 1562 5

Acquired resistance to classic caspase-mediated apoptosis is a common problem for the treatment of human cancer. Here, we show that siramesine, a novel sigma-2 receptor ligand, effectively induces caspase-independent programmed cell death in immortalized and transformed cells of various origins. Siramesine-treated tumor cells displayed increased levels of reactive oxygen species, lysosomal membrane permeabilization, chromatin condensation, and shrinkage and detachment of cells. Lipid antioxidants (alpha-tocopherol and gamma-tocopherol), but not other tested antioxidants (butylated hydroxyanisol or N-acetyl cysteine), effectively inhibited siramesine-induced morphologic changes and cell death. Cathepsin B inhibitors (CA-074-Me and R-2525) conferred similar, but less pronounced protection, whereas ectopic expression of antiapoptotic protein Bcl-2, lack of wild-type p53 as well as pharmacologic inhibitors of caspases (zVAD-fmk, DEVD-CHO, and LEHD-CHO), calpains (PD150606), and serine proteases (N-tosyl-L-phenylalanine chloromethyl ketone and pefabloc) failed to protect cells against siramesine-induced death. Importantly, transformation of murine embryonic fibroblasts with activated c-src or v-Ha-ras oncogenes greatly sensitized them to siramesine-induced cytotoxicity. Furthermore, p.o. administration of well-tolerated doses of siramesine had a significant antitumorigenic effect in orthotopic breast cancer and s.c. fibrosarcoma models in mice. These results present siramesine as a promising new drug for the treatment of tumors resistant to traditional therapies.
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PMID:Effective tumor cell death by sigma-2 receptor ligand siramesine involves lysosomal leakage and oxidative stress. 1620 71

Angiogenesis is the development of blood capillaries from pre-existing vessels. Vascular endothelial growth factor (VEGF) is a key regulator of vessel growth and regression, and acts as an endothelial survival factor by protecting endothelial cells from apoptosis. Many genes involved in cell proliferation and apoptosis are regulated by the nuclear factor kappa B (NFkappaB) transcription factor family. This study aimed to address the hypothesis that VEGF-mediated survival effects on endothelium involve NFkappaB. Using an NFkappaB-luciferase reporter adenovirus, we observed activation of NFkappaB following VEGF treatment of human umbilical vein endothelial cells. This was confirmed using electrophoretic mobility shift assay and found to involve nuclear translocation of NFkappaB sub-unit p65. However, NFkappaB activation occurred without degradation of inhibitory IkappaB proteins (IkappaBalpha, IkappaBbeta, and IkappaBepsilon). Instead, tyrosine phosphorylation of IkappaBalpha was observed following VEGF treatment, suggesting NFkappaB activation was mediated by degradation-independent dissociation of IkappaBalpha from NFkappaB. Adenovirus-mediated over-expression of either native IkappaBalpha, or of IkappaBalpha in which tyrosine residue 42 was mutated to phenylalanine, inhibited induction of NFkappaB-dependent luciferase activity in response to VEGF. Furthermore, VEGF-induced upregulation of mRNA for the anti-apoptotic protein Bcl-2 and cell survival following serum withdrawal was reduced following IkappaBalpha over-expression. This study highlights that different molecular mechanisms of NFkappaB activation may be involved downstream of stimuli which activate the endothelial lining of blood vessels.
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PMID:Vascular endothelial growth factor signalling in endothelial cell survival: a role for NFkappaB. 1641 78

Relative specific amino acid dependency is one of the metabolic abnormalities of cancer cells, and restriction of specific amino acids induces apoptosis of prostate cancer cells. This study shows that restriction of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln), or methionine (Met), modulates Raf and Akt survival pathways and affects the function of mitochondria in DU145 and PC3, in vitro. These three restrictions inhibit energy production (ATP synthesis) and induce generation of reactive oxygen species (ROS). Restriction of Tyr/Phe or Met in DU145 and Met in PC3 reduces mitochondrial membrane potential (DeltaPsim) and induces caspase-dependent and -independent apoptosis. In DU145, Tyr/Phe or Met restriction reduces activity of Akt, mitochondrial distribution of phosphorylated Raf and apoptosis inducing factor (AIF), and increases mitochondrial distribution of Bak. Mitochondrial Bcl-XL is increased in Tyr/Phe-restricted but decreased in Met-restricted cells. Under Tyr/Phe or Met restriction, reduced mitochondrial Raf does not inactivate the pro-apoptotic function of Bak. Tyr/Phe restriction also inhibits Bcl-2 and Met restriction inhibits Bcl-XL in mitochondria. These comprehensive actions damage the integrity of the mitochondria and induce apoptosis of DU145. In PC3, apoptosis induced by Met restriction was not associated with alterations in intracellular distribution of Raf, Bcl-2 family proteins, or AIF. All of the amino acid restrictions inhibited Akt activity in this cell line. We conclude that specific amino acid restriction differentially interferes with homeostasis/balance between the Raf and Akt survival pathways and with the interaction of Raf and Bcl-2 family proteins in mitochondria to induce apoptosis of DU145 and PC3 cells.
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PMID:Selective amino acid restriction targets mitochondria to induce apoptosis of androgen-independent prostate cancer cells. 1689 57

Relative specific amino acid dependency is one of the metabolic abnormalities of melanoma cells and metabolic studies of this dependency are in their infancy. Herein, we review the current studies in this area and present new information that adds to the understanding of how tyrosine (Tyr) and phenylalanine (Phe) dependency as well as other amino acids regulate the cell behaviors of melanoma cells. Amino acid dependency of human melanoma cells is multifactorial and restricting Tyr and Phe to melanoma triggers a series of alterations in metabolic and signaling pathways in a time-ordered fashion to alter different cellular behaviors. For example, at early time points, the reduction of Tyr and Phe alters metabolic reactions quantitatively or qualitatively. The alterations include modulation of integrin/focal adhesion kinase (FAK)/G protein pathways and the plasminogen activator (PA)/PA inhibitor pathways to inhibit tumor cell invasion. At later time periods, a further drop in intracellular amino acids induces more metabolic alterations to impact the FAK/Ras/Raf and Bcl-2 pathways leading to apoptosis. The threshold effects and the targeting of multiple pathways by restriction of specific amino acids provide a connection between the metabolic alterations and signaling pathways that modulate the cellular behaviors of melanoma cells. Decoding the metabolic alterations that connect amino acid concentration to the crucial step(s) in signaling is important and an exciting area of cancer research.
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PMID:Specific amino acid dependency regulates the cellular behavior of melanoma. 1751 32

c-Src tyrosine kinase plays a critical role in signal transduction downstream of growth factor receptors, integrins and G protein-coupled receptors. We used stable isotope labeling with amino acids in cell culture (SILAC) approach to identify additional substrates of c-Src tyrosine kinase in human embryonic kidney 293T cells. We have identified 10 known substrates and interactors of c-Src and Src family kinases along with 26 novel substrates. We have experimentally validated 4 of the novel proteins (NICE-4, RNA binding motif 10, FUSE-binding protein 1 and TRK-fused gene) as direct substrates of c-Src using in vitro kinase assays and cotransfection experiments. Significantly, using a c-Src specific inhibitor, we were also able to implicate 3 novel substrates (RNA binding motif 10, EWS1 and Bcl-2 associated transcription factor) in PDGF signaling. Finally, to identify the exact tyrosine residues that are phosphorylated by c-Src on the novel c-Src substrates, we designed custom peptide microarrays containing all possible tyrosine-containing peptides (312 unique peptides) and their mutant counterparts containing a Tyr --> Phe substitution from 14 of the identified substrates. Using this platform, we identified 34 peptides that are phosphorylated by c-Src. We have demonstrated that SILAC-based quantitative proteomics approach is suitable for identification of substrates of nonreceptor tyrosine kinases and can be coupled with peptide microarrays for high-throughput identification of substrate phosphopeptides.
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PMID:Identification of c-Src tyrosine kinase substrates using mass spectrometry and peptide microarrays. 1869 6

N-formyl-methionyl-leucyl-phenylalanine (fMLP) is a major chemotactic factor produced by Escherichia coli and other Gram-negative bacteria. In avian models the fMLP effects and the possible expression of FPRs have been poorly investigated. This report demonstrates that fMLP stimulation in vitro is able to elicit significant cellular responses from 10-day chick embryo nerve cells. Cell treatment with 10(-7) M fMLP at 37 degrees C induces a dramatic increase of nitric oxide (NO) production, after 24, 48, and 72 h, respectively. After 72 h of treatment with 10(-7) M fMLP the maximum nuclear translocation of the NF-kB complex protein p65 is visible, corresponding to the greatest NO production. In this context, 72 h of fMLP stimulation lead to a marked expression of the antiapoptotic protein Bcl-2, involved in cell survival. This suggests that activation of the NF-kB complex plays a protective role in chick neuronal cells treated with fMLP, confirmed by the significant neuronal cells degeneration observed after NF-kB inhibition with the specific inhibitor, TPCK. Overall, these data suggest a possible protective mechanism displayed by neurons against toxic molecules, like NO, released after cell exposure to bacterial products.
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PMID:f-Met-Leu-Phe stimulates nitric oxide production in chick embryo neurons: the role of NF-kB. 1872 Jan 65

N(alpha)-tosyl-L-phenylalanine chloromethylketone (TPCK) has been widely used to investigate signal transduction pathways that are involved in gene expression and cell survival/cell death. However, contradictory effects of TPCK on apoptosis have been reported, and the underlying signaling events leading to TPCK-induced promotion or prevention of apoptosis are not fully understood. Here, we show that TPCK induces caspase-dependent apoptosis in Epstein-Barr virus (EBV)-transformed human B cell lines with release of pro-apoptotic proteins from mitochondria. TPCK treatment also results in down-regulation of the anti-apoptotic proteins, cIAP1, cIAP2, and HAX-1, and caspase-dependent cleavage of the anti-apoptotic proteins, Bcl-2 and XIAP. Quantitative PCR analysis confirmed that the TPCK-induced down-regulation of HAX-1 occurred at the transcriptional level, and experiments using the specific pharmacological inhibitor, Bay 11-7082, suggested that HAX-1 expression is subject to regulation by the transcription factor, NF-kappaB. B cell lines derived from patients with homozygous HAX1 mutations were more sensitive to TPCK-induced apoptosis when compared with normal donor cell lines. Furthermore, N-acetylcysteine effectively blocked TPCK-induced apoptosis in EBV-transformed B cell lines and prevented the down-regulation or cleavage of anti-apoptotic proteins. Taken together, our studies demonstrate that TPCK induces apoptosis in human B cell lines and exerts multiple effects on pro- and anti-apoptotic factors.
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PMID:N(alpha)-tosyl-L-phenylalanine chloromethyl ketone induces caspase-dependent apoptosis in transformed human B cell lines with transcriptional down-regulation of anti-apoptotic HS1-associated protein X-1. 1967 60


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