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)

Bcl-2 and its analogs protect different classes of neurons from apoptosis in several experimental situations. These proteins may therefore provide a means for treatment of neurodegenerative diseases. We examined the effects of Bcl-2 overexpression in a genetic mouse model with motor neuron disease (progressive motor neuronopathy/pmn). Pmn/pmn mice lose motoneurons and myelinated axons, and die at 6 weeks of age. When these mice were crossed with transgenic mice that overexpress human Bcl-2, there was a rescue of the facial motoneurons with a concomitant restoration of their normal soma size and expression of choline acetyltransferase. However, Bcl-2 overexpression did not prevent degeneration of myelinated axons in the facial and phrenic motor nerves and it did not increase the life span of the animals. Since Bcl-2 acts strictly on neuronal cell body survival without compensating for nerve degeneration in pmn/pmn/bcl-2 mice, this proto-oncogene would not in itself be sufficient for treatment of neurodegenerative diseases where axonal impairment is a major component.
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PMID:Bcl-2 overexpression prevents motoneuron cell body loss but not axonal degeneration in a mouse model of a neurodegenerative disease. 747 23

The expression of the proto-oncogene bcl-2 was examined in a panel of 75 continuous human leukemia-lymphoma cell lines originated from different hematopoietic cell types. The presence of the bcl-2 protein, as evidenced by Western blotting, and its mRNA, as determined by Northern blotting, were not restricted to cells with the chromosomal translocation t(14;18)(q32;q21), but were also detected in a large number of cell lines without t(14;18). The amount of the bcl-2 protein and mRNA in the cell lines with t(14;18) was in the same order of magnitude as in other bcl-2 expressing cell lines of the same lineage, but without the translocation. Bcl-2 was found in all types of hematopoietic cell lines which were assigned to the following lineages based on their phenotypical characteristics: pre-B, B, plasma, T, myeloid, monocytic, erythroid-megakaryocytic and Hodgkin's lymphoma derived cell lines. The levels of accumulated mRNA and protein corresponded fairly well in most of the cell lines examined. Our results suggest the notion that bcl-2 expression is widely present in hematopoietic cell lines without restriction to single lineages and, in fact, clearly independent of the chromosomal aberration t(14;18). It is conceivable that bcl-2 expression is a common feature in established hematopoietic cell lines and may contribute to their unlimited growth in vitro.
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PMID:Expression of bcl-2 mRNA and protein in leukemia-lymphoma cell lines. 747 72

It appears that the switch recombination machinery of a B lymphocyte targets preferentially unrearranged heavy chain genes that have been rendered transcriptionally active. Transcriptional activation of the 'germline' human C alpha 1 and C alpha 2 genes is triggered by TGF-beta 1 and is controlled by proximal positive and distal negative regulatory elements residing upstream of the alpha 1 and alpha 2 switch regions respectively. In this report we characterize the positive proximal regulatory elements and analyse their interaction with DNA binding proteins. Our data demonstrate that a 100 bp fragment that contains a cAMP responsive element (CRE)/activating transcription factor (ATF) motif, a putative Ets binding site and an element that is created by two previously described neighbouring direct repeats (DRE), can increase the basal level of transcription and confer TGF-beta 1 inducibility to a heterologous promoter in an orientation- and position-independent manner. Ubiquitously expressed DNA binding proteins interact specifically with the CRE/ATF, the Ets site and the DRE element. Additionally, nuclear proteins interact with sequences which are located downstream of this enhancer are not essential for transcription in the transient expression assays utilized; however, they contain motifs that have been previously implicated in regulating DNA recombination events. These motifs include a Chi motif and a Chi-like element previously found in the recombination hotspot region of the Bcl-2 proto-oncogene and close to chromosomal breakpoints in T-ALL lines. Our findings raise the possibility that the intervening region associated regulatory elements in addition to regulating the transcriptional activation of the Ig heavy chain genes could also facilitate the physical interaction of transcription and recombination controlling molecular mechanisms.
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PMID:The human I alpha 1 region contains a TGF-beta 1 responsive enhancer and a putative recombination hotspot. 749 26

The regulatory Tat protein of human immunodeficiency virus type-1 (HIV-1) exerts a pleyotropic activity on the survival and proliferation of different cell types in culture. In this report, we investigated the effect of either endogenous or exogenous Tat on Bcl-2 proto-oncogene expression and cell survival in Jurkat T-cell lines and primary peripheral blood mononuclear cells. Stable and transient transfections of Jurkat cells with the cDNA of tat and a plasmid containing Bcl-2 promoter in front of CAT (Bcl-2 Pr/CAT) stimulated CAT activity and showed an increase of Bcl-2 mRNA and protein expression. This effect was specifically related to tat, because Jurkat cells transfected with the cDNA of tat in antisense orientation, tat carrying a mutation in the amino acid cys22-gly22, or the control vector alone (pRPneo-SL3) did not show any significant difference in Bcl-2 promoter activity with respect to parental Jurkat cells. We also observed a specific correlation between tat-induced Bcl-2 gene expression and inhibition of apoptosis induced by serum withdrawal. Our results suggest that the structural integrity of the activation domain of Tat was required for the promotion of the Bcl-2 promoter and Jurkat cell survival, because a single mutation in the aminoacid cys22 was sufficient to completely block the upregulation of Bcl-2 and inhibition of apoptosis. Moreover, picomolar concentrations of native or recombinant Tat were able to upregulate Bcl-2 expression both in Jurkat and primary peripheral blood mononuclear cells, suggesting that extracellular Tat, actively released by infected cells, may also play a significant role in suppressing apoptosis. An aberrant cell survival of lymphoid cells consequent to the upregulation of Bcl-2 may represent an additional pathogenetic mechanism that could help explain both the dysregulated immune response and the frequent occurrence of hyperplastic/neoplastic disorders in HIV-1-seropositive individuals.
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PMID:The human immunodeficiency virus type-1 Tat protein upregulates Bcl-2 gene expression in Jurkat T-cell lines and primary peripheral blood mononuclear cells. 757 50

Apoptosis is a major form of cell death induced by chemotherapeutic drugs. Overexpression of the proto-oncogene bcl-2 can prevent apoptosis in various types of cells. We have constructed a HeLa S3 cell line in which the expression of bcl-2 can be controlled by the concentration of tetracycline in the medium. Using this system, we show that apoptosis induced by various cytostatic treatments could be delayed by the overexpression of bcl-2, as assayed by vital dye exclusion, apoptotic nuclei morphology, DNA histogram shift, and DNA fragmentation. Quantitative analysis revealed a hyperbolic curve when protection from apoptosis was plotted against the amount of Bcl-2. When cells were treated with aphidicolin for 12, 24, or 36 h and then replated in fresh media to assay for colony formation, the majority of cells that did not show apoptotic morphology at the time of drug removal failed to form colonies. Furthermore, Bcl-2 did not increase colony formation after 12-36 h of aphidicolin treatment. Therefore, with aphidicolin treatment, cells were committed to the death program upstream of the point of Bcl-2 action.
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PMID:BCL-2 expression delays drug-induced apoptosis but does not increase clonogenic survival after drug treatment in HeLa cells. 758 31

The mechanisms of luteal regression and rescue in women are unknown but forms of programmed cell death may be involved. The proto-oncogene bcl-2 is an important inhibitor of apoptosis but has not previously been described in the human corpus luteum. Immunohistochemical localization of bcl-2 protein was investigated in human corpora lutea obtained from women undergoing surgery during endocrine monitored menstrual cycles as well as from women who had been treated with human chorionic gonadotrophin (HCG) to prolong the luteal phase. Bcl-2 was found to be localized in granulosa-lutein, theca-lutein (as identified by co-localization of P450(17)alpha-hydroxylase) and the endothelial cells around some blood vessels. Immunoblotting demonstrated the presence of a single band of approximately MW 26 kDa. There was no apparent change in either the intensity of immunostaining or the histological localization during the normal luteal phase or following treatment with human chorionic gonadotrophin. The product of the proto-oncogene bcl-2 is present in the human corpus luteum. It is unlikely that bcl-2 expression alone is responsible for prolongation of the lifespan of the corpus luteum in early pregnancy although it is possible that the action of the bcl-2 gene present is modified by changes in other members of the bcl-2 family.
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PMID:Immunolocalization of bcl-2 in the human corpus luteum. 759 40

Recent evidence has shown that two of the three key genes in the programmed cell death pathway of Caenorhabditis elegans, ced-9 (a cell death suppressor) and ced-3 (a cell death inducer), encode proteins that share structural and functional similarities with the mammalian proto-oncogene product Bcl-2 and interleukin-1 beta converting enzyme, respectively. These findings reveal key molecules that control life and death decisions in vertebrates.
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PMID:Molecular control of life and death. 761 73

Recent studies have shown that the Bcl-2 protein suppresses programmed cell death or apoptosis induced by a variety of stimuli including chemotherapeutic drugs. Because estrogen promotes the survival of estrogen-dependent breast cancer cells in vivo, we investigated whether estrogen might regulate levels of Bcl-2 gene expression in an estrogen-responsive human breast cancer cell line. Estrogen receptor-positive MCF-7 human breast cancer cells cultured in the presence of estrogen express the 8.5-kb Bcl-2 mRNA transcript. Depletion of estrogen from the medium results in loss of expression of the mRNA, whereas reexposure to estrogen markedly induces the Bcl-2 transcript. The changes in Bcl-2 mRNA are paralleled by changes in Bcl-2 protein levels. Estrogen-induced increases in Bcl-2 are significantly inhibited by inclusion of the pure antiestrogen ICI 164,384 in the medium. The Bax protein that heterodimerizes with Bcl-2 and promotes cell death is expressed in MCF-7 cells grown in the presence of estrogen and is unaffected by culture in estrogen-free medium. Estrogen depletion doubles the sensitivity of MCF-7 cells to the cytotoxic effects of Adriamycin compared with cells cultured in medium supplemented with estrogen, consistent with a decrease in the Bcl-2 levels. MCF-7 cells treated simultaneously with estrogen and ICI 164,384 exhibit markedly lower resistance to Adriamycin compared with cells treated with estrogen alone. In the absence of estrogen, MCF-7 cells transfected with Bcl-2 expression plasmids display a marked increase in resistance to Adriamycin. In the presence of estrogen, MCF-7 cells expressing Bcl-2 antisense transcripts are rendered twice as sensitive to acute Adriamycin cytotoxicity as a control clone. We conclude that estrogen can promote resistance of estrogen receptor bearing human breast cancer cells to chemotherapeutic drugs through a mechanism that involves regulation of the Bcl-2 proto-oncogene.
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PMID:Estrogen promotes chemotherapeutic drug resistance by a mechanism involving Bcl-2 proto-oncogene expression in human breast cancer cells. 764 Dec 10

The bcl-2 proto-oncogene product inhibits apoptosis. It has been suggested that bcl-2 assists the survival of stem cells. Bcl-2 also plays a role in the development of adenomas. In salivary glands it is expressed in basal cells of striated and excretory ducts which may indicate that these cells are reserve cells. Acinar cells, myoepithelial cells and most luminal cells are negative for bcl-2. In basal cell adenomas and Warthin's tumors it is found predominantly in cells with basal cell differentiation. In pleomorphic adenomas bcl-2 is expressed mainly in basal cells of tubulo-ductal structures, at various degrees and patterns in solid and trabecular areas and at low degree in myxoid areas. In chondroid areas of pleomorphic adenomas, in myoepitheliomas and oncocytomas it is only focally expressed or missing. If the inhibition of apoptosis plays a significant role in the genesis of these neoplasms, then factors other than bcl-2 must be effective.
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PMID:Expression of bcl-2 in salivary glands and salivary gland adenomas. A contribution to the reserve cell theory. 765 31

The proto-oncogene bcl-2, isolated from the t(14;18) chromosomal breakpoint in follicular B-lymphoma, and a bcl-2-related gene bcl-x (ref. 4) prevent apoptotic cell death induced by various treatments. Although a mechanism has been proposed that involves Bcl-2 activity on reactive oxygen species (ROS), expression of Bcl-2 or Bcl-xL prevents cell death induced by withdrawal of oxygen (hypoxia), which drastically decreases the net formation of oxygen free radicals and does not increase oxidized lipid, protein or DNA. Furthermore, neither ROS scavenger nor inhibitor of ROS scavenger affects cell death, regardless of the expression of Bcl-2 or Bcl-xL. Thus our data suggest that Bcl-2 and Bcl-xL exert an anti-cell death function by a mechanism other than regulation of ROS activity.
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PMID:Prevention of hypoxia-induced cell death by Bcl-2 and Bcl-xL. 772 26


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