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)

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the environment. Benzo[a]pyrene (B[a]P), a prototypical member of this class of chemicals, affects cellular signal transduction pathways and induces apoptosis. In this study, the proximate carcinogen of B[a]P metabolism, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (B[a]P-7,8-dihydrodiol) and the ultimate carcinogen, B[a]P-r-7,t-8-dihydrodiol-t-9,10-epoxide(+/-) (BPDE-2) were found to induce apoptosis in human HepG2 cells. Apoptosis initiated by B[a]P-7,8-dihydrodiol was linked to activation of the Ah receptor and induction of CYP1A1, an event that can lead to the formation of BPDE-2. With both B[a]P-7,8-dihydrodiol and BPDE-2 treatment, changes in anti- and pro-apoptotic events in the Bcl-2 family of proteins correlated with the release of mitochondrial cytochrome c and caspase activation. The onset of apoptosis as monitored by caspase activation was linked to mitogen-activated protein (MAP) kinases. Utilizing mouse hepa1c1c7 cells and the Arnt-deficient BPRc1 cells, activation of MAP kinase p38 by B[a]P-7,8-dihydrodiol was shown to be Ah receptor-dependent, indicating that metabolic activation by CYP1A1 was required. This was in contrast to p38 activation by BPDE-2, an event that was independent of Ah receptor function. Confirmation that MAP kinases play a critical role in BPDE-2-induced apoptosis was shown by inhibiting caspase activation of poly(ADP-ribose)polymerase 1 (PARP-1) by chemical inhibitors of p38 and ERK1/2. Furthermore, mouse embryo p38-/- fibroblasts were shown to be resistant to the actions of BPDE-2-induced apoptosis as determined by annexin V analysis, cytochrome c release, and cleavage of PARP-1. These results confirm that the Ah receptor plays a critical role in B[a]P-7,8-dihydrodiol-induced apoptosis while p38 MAP kinase links the actions of an electrophilic metabolite like BPDE-2 to the regulation of programmed cell death.
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PMID:The role of the Ah receptor and p38 in benzo[a]pyrene-7,8-dihydrodiol and benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide-induced apoptosis. 1263 98

Survival and proliferation of cells of a human myelo-erythroid CD34+ leukemia cell line (TF-1) depend on the presence of granulocyte-macrophage colony-stimulating factor or interleukin-3. Upon hormone withdrawal these cells stop proliferating and undergo apoptotic process. In this report we demonstrate that a controlled increase in [Ca2+]i induces hormone-independent survival and proliferation of TF-1 cells. We found that moderate elevation of [Ca2+]i by the addition of cyclopiasonic-acid protected TF1 cells from apoptosis. Furthermore, a higher, but transient elevation of [Ca2+]i by ionomycin treatment induced cell proliferation. In both cases caspase-3 activity was reduced, and Bcl-2 was up-regulated. Higher elevation of [Ca2+]i by ionomycin induced MEK-dependent biphasic ERK1/2 activation, sufficient to move the cells from G0/G1 to S/M phases. Meanwhile, activation of ERK1/2, phosphorylation of the Elk-1 transcription factor, and, consequently, a substantial elevation of Egr-1 and c-Fos levels and AP-1 DNA binding were observed. Moderate elevation of [Ca2+]i, on the other hand, caused a delayed monophasic activation of ERK1/2 and Elk-1 that was accompanied with only a small increase of Egr-1 and c-Fos levels and AP-1 DNA binding. The specific MEK-1 kinase inhibitor, PD98059, inhibited all the effects of increasing [Ca2+]i, indicating that the MAPK/ERK pathway activation is essential for TF-1 cell survival and proliferation. Based on these results we suggest that the elevation of the [Ca2+]i may influence the cytokine dependence of hemopoietic progenitors and may contribute to pathological hematopoiesis.
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PMID:Calcium induces cell survival and proliferation through the activation of the MAPK pathway in a human hormone-dependent leukemia cell line, TF-1. 1264 64

We previously showed (Gastroenterology 123: 206-216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through G(i)-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.
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PMID:LPA protects intestinal epithelial cells from apoptosis by inhibiting the mitochondrial pathway. 1268 13

In a previously published report (Kurland, J. F., Kodym, R., Story, M. D., Spurgers, K. B., McDonnell, T. J., and Meyn, R. E. (2001) J. Biol. Chem. 276, 45380-45386), we described the NF kappa B status for two murine B-cell lymphoma cell lines, LY-as (apoptosis-sensitive) and LY-ar (apoptosis-refractory) and provided evidence that NF kappa B1 (p50) homodimers contribute to the expression of Bcl-2 in the LY-ar line. In the present study, we investigated the upstream signals leading to p50 homodimer activation and Bcl-2 expression. We found that in LY-ar cells, ERK1 and ERK2 were constitutively phosphorylated, whereas LY-as cells had no detectable ERK1 or ERK2 phosphorylation. Treatment of LY-ar cells with the MEK inhibitors PD 98059, U0126, and PD 184352 led to a loss of phosphorylated ERK1 and ERK2, a reversal of nuclear p50 homodimer DNA binding, and a decrease in Bcl-2 protein expression. Similarly, activation of the MEK/ERK pathway in LY-as cells by phorbol ester led to Bcl-2 expression that could be blocked by PD 98059. Furthermore, treatment of LY-ar cells with tumor necrosis factor-alpha, an I kappa B kinase activator, did not alter the suppressive effect of PD 98059 on p50 homodimer activity, suggesting an I kappa B kinase-independent pathway for p50 homodimer activation. Lastly, all three MEK inhibitors sensitized LY-ar cells to radiation-induced apoptosis. We conclude that the MEK/ERK pathway acts upstream of p50 homodimer activity and Bcl-2 expression in this B-cell lymphoma cell system and suggest that the use of MEK inhibitors could be useful clinically in combination with ionizing radiation to treat lymphoid malignancies.
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PMID:The MEK/ERK pathway acts upstream of NF kappa B1 (p50) homodimer activity and Bcl-2 expression in a murine B-cell lymphoma cell line. MEK inhibition restores radiation-induced apoptosis. 1280 33

To investigate the role of thrombin in regulating apoptosis, we have used CCl39 cells, a fibroblast cell line in which thrombin-induced cell proliferation has been extensively studied. Withdrawal of serum from CCl39 cells resulted in a rapid apoptotic response that was completely prevented by the inclusion of thrombin. The protective effect of thrombin was reversed by pertussis toxin, suggesting that cell-survival signalling pathways are activated via a G(i) or G(o) heterotrimeric GTPase. Serum-withdrawal-induced death required de novo gene expression and was preceded by the rapid de novo expression of the pro-apoptotic 'BH3-only' protein Bim (Bcl-2-interacting mediator of cell death). Thrombin strongly inhibited the up-regulation of both Bim protein and Bim mRNA. The ability of thrombin to repress Bim expression, and to protect cells from apoptosis, was reversed by U0126, a MEK1/2 [MAPK (mitogen-activated protein kinase) or ERK (extracellular-signal-regulated kinase) 1/2] inhibitor, or LY294002, a phosphoinositide 3'-kinase (PI3K) inhibitor, suggesting that both the Raf-->MEK-->ERK1/2 and PI3K pathways co-operate to repress Bim and promote cell survival. A PAR1p (protease-activated receptor 1 agonist peptide) was also able to protect cells from serum-withdrawal-induced apoptosis, suggesting that thrombin acts via PAR1 to prevent apoptosis.
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PMID:Thrombin inhibits Bim (Bcl-2-interacting mediator of cell death) expression and prevents serum-withdrawal-induced apoptosis via protease-activated receptor 1. 1284 49

Sodium salicylate is known to induce apoptosis in a variety of cancer cells. However, the molecular mechanism for salicylate-induced apoptosis is yet unclear. Here we show that in HCT116 colon carcinoma cells, 10 mM sodium salicylate induces caspase-3 activation and degradation of its substrates, poly(ADP-ribose) polymerase (PARP), beta-catenin, and retinoblastoma (Rb). In contrast, sodium salicylate did not exert any significant effects on the expression of Fas L that is implicated in extrinsic apoptotic pathway and the levels of Bcl-2 family proteins, Bcl-2, Bcl-xsl, and Bad, which are involved in intrinsic apoptotic pathway, and anti-apoptotic molecules, c-IAP1 and HSP73. In addition, 10 mM salicylate induced p53 tumor suppressor protein that plays an important role in cell cycle arrest or apoptosis and the induction seemed to be linked to its phosphorylation at Set 15. To investigate the signal pathways for salicylate-induced apoptosis, we examined the effects of sodium salicylate on protein kinase activities. Sodium salicylate activated p38MAPK through phosphorylation at Thr 180/Tyr 182 and Akt/PKB at Ser 473, whereas it partially activated ERK1/2 through its phosphorylation at Thr 202/Tyr 204. We also show that SB203580 (a specific p38MAPK inhibitor), but not other protein kinase inhibitors (PD98059, LY294002, and wortmannin), significantly prevented salicylate-induced apoptosis. These results suggest that sodium salicylate-induced apoptosis in HCT116 colorectal cancer cells is mediated by p38MAPK.
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PMID:Sodium salicylate induces apoptosis in HCT116 colorectal cancer cells through activation of p38MAPK. 1285 2

Global gene expression during the induction of ion pair-mediated apoptosis was evaluated by an apoptosis microarray system. Human bone marrow stromal cells were cultured in the presence of 10(-6) M dexamethasone to promote osteogenesis. After 28 days, these cells expressed elevated alkaline phosphatase activity and maintained Cbfa1 expression even when challenged with an apoptogen. Apoptosis was initiated by treating cells with 3 mM Ca(2+) and 5 mM Pi for 4 h. 32P-Labeled mRNA was hybridized to a human apoptosis microarray containing 205 cDNA fragments. We found that apoptosis influenced the expression of 15 genes mainly involved in cell cycle and cell signaling. These genes included IGFBPs and ERK1, known to play a role in cell survival; GST and GST mu, required for maintenance of thiol redox; TNFR1, a gene product that initiates cell death; and finally, BAD, a gene that encodes a proapoptotic protein. Real-time PCR analysis showed that the expression of ERK1, TNFR1, and GST was modulated by 1.89-, 2.66-, and 1.6 fold after 4 h and by 1-, 1.91-, and 1.5 fold, respectively, after 8 h treatment with the ion pair. In addition, we also measured the expression of Bcl-2 and Bax by quantitative RT-PCR. We noted that these two genes were increased 3.07 and 2.99 fold, respectively, after 8 h treatment with the apoptogen. Results of this study suggest that the ion pair influenced ERK1 and TNFR1 signaling pathways and affected thiol metabolism, whereas Bcl-2 and Bax were expressed at late stages of the death process.
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PMID:Detection of apoptotic gene expression in human osteoblast-like cells by cDNA microarrays. 1292 26

The silencer of death domains (SODD) has been proposed to prevent constitutive signaling of tumor necrosis factor receptor 1 (TNFR1) in the absence of ligand. Besides TNFR1, death receptor 3 (DR3), Hsp70/Hsc70, and Bcl-2 have been characterized as binding partners of SODD. In order to investigate the in vivo role of SODD, we generated mice congenitally deficient in expression of the sodd gene. No spontaneous inflammatory infiltrations were observed in any organ of these mice. Consistent with this finding, in the absence of SODD no alteration in the activation patterns of nuclear factor kappaB (NF-kappaB), stress kinases, or ERK1 or -2 was observed after stimulation with tumor necrosis factor (TNF). Activation of NF-kappaB by DR3 was also unchanged. The extents of DR3- and TNF-induced apoptosis were comparable in gene-deficient and wild-type cells. Protection of cells against heat shock as mediated by the Hsp70 system and against staurosporine-induced apoptosis was independent of SODD. Furthermore, resistance to high-dose lipopolysaccharide (LPS) injections, LPS-D-GalN injections, and infection with listeriae was similar in wild-type and gene-deficient mice. In conclusion, our data do not support the concept of a unique, nonredundant role of SODD for the functions of TNFR1, Hsp70, and DR3.
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PMID:Apparently normal tumor necrosis factor receptor 1 signaling in the absence of the silencer of death domains. 1294 86

Because the MAPK pathway plays important roles in cell proliferation and inhibition of apoptosis, this pathway has emerged as a potential therapeutic target for solid tumors and leukemia. At the present time there is little information about activation of this pathway and the consequences of its inhibition in acute lymphocytic leukemia cells (ALL). In the present study, constitutive MAPK pathway activation, as evidenced by phosphorylation of ERK1 and ERK2, was observed in 8 of 8 human lymphoid cell lines and 33% (8:24) of pretreatment ALL bone marrows. Inhibition of this pathway by the MEK inhibitors CI-1040 and PD098059 induced apoptosis through a unique pathway involving dephosphorylation and aggregation of Fas-associated death domain protein followed by death receptor-independent caspase-8 activation. Jurkat cell variants lacking Fas-associated death domain protein or procaspase-8 were resistant to CI-1040-induced apoptosis, as were Jurkat or Molt3 cells treated with the O-methyl ester of the caspase-8 inhibitor N-(Nalpha-benzyloxycarbonylisoleucylglutamyl) aspartate fluoromethyl ketone. In contrast, CI-1040-induced apoptosis was unaffected by blocking anti-Fas antibody, soluble tumor necrosis factor-alpha-related apoptosis-inducing ligand decoy receptor, or transfection with cDNA encoding the anti-apoptotic Bcl-2 family member Mcl-1 or dominant negative caspase-9. Collectively, these results identify the MAPK pathway as a potential therapeutic target in ALL and delineate a mechanism by which MEK inhibition triggers apoptosis in ALL cells.
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PMID:Central role of Fas-associated death domain protein in apoptosis induction by the mitogen-activated protein kinase kinase inhibitor CI-1040 (PD184352) in acute lymphocytic leukemia cells in vitro. 1296 34

It is believed that bisphosphonates (BPs) induce apoptosis in cells such as myeloma cells, as they inhibit prenylation of G-proteins. However, the details of the apoptosis-inducing mechanism remain obscure. In the present study, we attempted to clarify the mechanism by which YM529, a new bisphosphonate, induces apoptosis. YM529 induced cell deaths in HL60 cells in a concentration-dependent manner. At that time, we observed an increase in Caspase-3 activity and morphological fragmentation of the nuclei. We could confirm that these cell deaths were evidence of apoptosis. The apoptosis induced by YM529 was not inhibited by the addition of farnesyl pyrophosphate (FPP), but was by the addition of geranylgeranyl pyrophosphate (GGPP). When we examined the survival signals at the time of apoptotic induction, we also observed that the administration of YM529 caused a remarkable decrease in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). However, other survival signals such as nuclear factor kappa B (NF-kappaB), protein kinase B (Akt), and p38 mitogen-activated protein kinase (p38) exhibited no change. In addition, no quantitative change was observed in Bcl-2, which is an anti-apoptosis protein. It was also observed that apoptosis was induced when U0126, an MEK inhibitor, was added to the cells to inhibit ERK. These results suggest that YM529, the new bisphosphonate, induced apoptosis when inhibit GGPP synthase and consequently decreased the levels of phosphorylated ERK, which is a survival signal; moreover, during this process, there is no influence on NF-kappaB, Akt, p38, and Bcl-2. The results of this study also suggest that YM529 can be used as an anticancer agent, in addition to its use as a therapeutic agent to treat osteoporosis.
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PMID:A new bisphosphonate, YM529 induces apoptosis in HL60 cells by decreasing phosphorylation of single survival signal ERK. 1367 34


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