Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:A9QXG9 (bcl-2)
 7,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Continuous proliferation of the immortalized myeloid progenitor cell line FDC-P1 depends on stimulation with either interleukin-3 (IL-3) or granulocyte-macrophage colony stimulating factor (GM-CSF). Two other cytokines, interferon-gamma (IFN-gamma) and IL-4, were found to prolong FDC-P1 survival for several days. Surviving cells incorporated [3H]thymidine and a minority completed up to 3 cell divisions before dying. This transient proliferative response was a direct effect of IFN-gamma and IL-4 since these cytokines did not induce production of detectable IL-3 or GM-CSF and the response was unaffected by cell concentration. IL-6, a constitutive product of FDC-P1 cells whose secretion was increased by IL-3, GM-CSF and IL-4 but not by IFN-gamma, was not responsible for the proliferative response. FDC-P1 lines that constitutively expressed the cell cycle-associated oncogene myc or the survival-associated oncogene bcl-2 also responded only transiently to IFN-gamma or IL-4, indicating that expression of these genes did not complement the signals delivered by IFN-gamma or IL-4. By contrast, the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) prolonged survival of FDC-P1 cells on its own and potentiated the response to IFN-gamma or IL-4, although the combination of stimuli did not support long-term growth. It is concluded that IFN-gamma and IL-4 trigger only some of the signalling events that lead to mitogenesis; these events are complemented by stimulation with PMA but additional signals are required for sustained proliferation.
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PMID:Survival of the myeloid progenitor cell line FDC-P1 is prolonged by interferon-gamma or interleukin-4. 138 29

Fas Ag is a cell surface protein that can mediate apoptosis and belongs to the TNF receptor family. The product of protooncogene bcl-2, a membrane-associated protein, has been shown to inhibit apoptosis in various hematopoietic cells including B cells and T cells. To examine the possible interaction of the Fas Ag and bcl-2, we coexpressed human Fas Ag and bcl-2 cDNA in murine IL-3-dependent FDC-P1 cell line and murine lymphoma WR19L. FDC-P1 transformants expressing bcl-2 showed a prolonged survival to IL-3 depletion. FDC-P1 transformants expressing the Fas Ag alone were killed by anti-Fas antibody in the presence of IL-3. Overexpression of bcl-2 in FDC-P1 resulted in a partial inhibition of Fas-induced cell death. WR19L transformants expressing bcl-2 were partially resistant to the cytolytic activities of the TNF-alpha and anti-Fas antibody treatment. These results suggest that the Fas Ag and TNF receptor may share the same signaling pathway, and that bcl-2 interferes with the apoptotic process mediated by the Fas Ag and TNF receptor.
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PMID:Effect of bcl-2 on Fas antigen-mediated cell death. 768 19

Expression of c-myc and macromolecular synthesis have been associated with physiological cell death. We have studied their requirement for the death of factor (interleukin-3)-dependent cells (FDC-P1) bearing an inducible bcl-2 expression construct. FDC-P1 cells expressing bcl-2 turned off expression of c-myc when deprived of interleukin-3 but remained viable as long as bcl-2 was maintained. A subsequent decline in Bcl-2 allowed the cells to undergo apoptosis directly from G0, in the absence of detectable c-myc expression. Thus c-myc expression may lead to apoptosis in some cases but is not directly involved in the mechanism of physiological cell death that can be controlled by Bcl-2. The macromolecular synthesis inhibitors actinomycin D and cycloheximide triggered rapid cell death of FDC-P1 cells in the presence of interleukin-3, but the cells could be protected by Bcl-2. Thus, the cell death machinery can exist in a quiescent state and can be activated by mechanisms that do not require synthesis of RNA or protein.
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PMID:Neither macromolecular synthesis nor myc is required for cell death via the mechanism that can be controlled by Bcl-2. 769 34

Amebic destruction of neutrophils and macrophages is contact-dependent. Adherence is mediated by a galactose-specific surface lectin on the amebic membrane. The pathway by which contact-dependent cytolysis of the target cell occurs is unknown. We hypothesized that target cell death is due to the triggering of apoptosis (programmed cell death) by the amebae. The purpose of this study was to determine whether target cell DNA is fragmented into a ladder pattern characteristic of apoptosis and to test whether overexpression of Bcl-2, a protein that confers resistance to apoptotic death from some stimuli, blocks target cell killing. The murine myeloid cell line FDC-P1 transfected with a retrovirus construct expressing the Bcl-2 protein was shown to be resistant to the apoptotic death that the parental line undergoes upon growth factor deprivation. 51Cr-labeled FDC-P1 control or bcl-2-transfected cells were incubated with Entamoeba histolytica (4:1 cell/ameba ratio) and killing of the cells was assessed by 51Cr release. Both cell lines were susceptible to contact-dependent killing. Death induced by the amebae in the bcl-2-transfected cells resulted in a DNA ladder fragmentation pattern (using [125I]iododeoxyuridine-labeled target cell DNA) identical to that seen in the control cells undergoing apoptosis upon growth factor withdrawal. Target cell DNA fragmentation was inhibited by blocking adherence with galactose. Our data suggest that target cell killing by E. histolytica can occur via Bcl-2-independent apoptotic mechanism.
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PMID:Entamoeba histolytica: target cells killed by trophozoites undergo DNA fragmentation which is not blocked by Bcl-2. 795 63

The AIDS-associated lymphomas represent a heterogeneous set of disease processes. The largest histologic subset of lymphomas is the large-cell lymphomas, which represent a spectrum of disease processes ranging from monomorphic monoclonal B-cell proliferations to very polymorphic and polyclonal mixtures of B cells, T cells and macrophages. The next most frequent class of systemic lymphoma are the small non-cleaved cell or Burkitt's-like lymphomas. These are relatively monomorphic, monoclonal malignant B-cell proliferations. The final subset of lymphomas, which are likely to become more common as the AIDS epidemic progresses, are the primary CNS lymphomas, which are expansions of EBV-immortalized B cells. The high incidence of tumor-associated EBV in the CNS lymphomas makes these lesions somewhat analogous to an opportunistic EBV infection. In HIV disease there is a long lag after infection before the appearance of clinical manifestations of impaired T-cell immunity. During this period, both appropriate B-cell proliferation in response to antigen (including the ubiquitous HIV) and abnormal B-cell proliferation (autoimmune, dysregulated) occur as the follicular architecture is disrupted by the virus and potential APC are exposed and/or infected with HIV. The destruction of FDC or the involution of their processes could interfere with the elimination by apoptosis of low-avidity B-cell clones. Antigen-competent B cells with pre-existing chromosomal translocations such as the t(8;14) (c-myc, IgH) would have a selective growth advantage in this setting. Figure 9 shows a schematic representation of prelymphomatous and lymphomagenic events as they are projected to occur. A similar pathogenetic scheme has been postulated for follicular B-cell lymphomas: PCR studies have demonstrated that a pool of t(14;18) (IgH;bcl-2) B-cells are present in lymph nodes featuring follicular hyperplasia. In response to antigen (the evidence favoring antigen drive is extensive hypersomatic mutation in sequences related to binding sites), B cells with the t(14;18) translocation have a selective advantage because the bcl-2 oncogene confers a resistance to apoptosis. Burkitt's lymphomas, particularly sporadic or HIV variants, fulfill at least the key criteria for antigen competence, mainly the presence of surface Ig. The c-myc-associated chromosomal translocational events are likely to occur early during the enzymatic machinations of gene rearrangement. Such B cells would be in the dysregulated cytokine and antigen milieu of HIV disease and ultimately could have a selective advantage. EBV infection of B cells probably requires activation and expression of the CD21 receptor. Furthermore, CD5+ B cells of CLL are refractory to EBV infection.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pathogenesis of AIDS lymphomas. 798 99

The bcl-2 oncogene product delays apoptotic cell death and prolongs the cell survival. We cloned two bcl-2-related cDNAs from a rat thymus cDNA library by low stringency hybridization with a rat bcl-2 fragment as a probe. One of these, designated bcl-xalpha, was a counterpart of the human bcl-xL reported previously as a bcl-2-related gene (Boise, L. H., Gonzalez-Garcia, M., Postema, C. E. , Ding, L., Lindsten, T., Turka, L. A., Mao, M., Nunez, G., and Thompson, C. B. (1993) Cell 74, 597-608). The other, designated bcl-xbeta, was novel and found to be generated by an unspliced mRNA, whereas bcl-xalpha was generated from a spliced transcript. The splice junction exactly corresponded to that found in the bcl-2 gene. bcl-xbeta was specifically expressed in cerebellum, heart, and thymus. When bcl-xbeta directed by a strong promoter was introduced into an interleukin-3-dependent promyeloid cell line, FDC-P1, DNA fragmentation was observed even in the growing state in the presence of interleukin-3 although not in the control transfectants. This finding suggests that the rat bcl-xbeta gene product promotes apoptosis in the promyeloid cells.
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PMID:An additional form of rat Bcl-x, Bcl-xbeta, generated by an unspliced RNA, promotes apoptosis in promyeloid cells. 866 75

Two pathways have been implicated in the induction of apoptosis by cytotoxic T cells: the granule exocytosis pathway and a pathway using CD95 (Fas/APO-1). To test whether apoptosis induced by either of these pathways could be blocked by Bcl-2, we exposed bcl-2-transfected cells to CTL derived from normal, perforin-deficient, or CD95 ligand mutant (gld) mice. Although the levels of Bcl-2 expression achieved were able to protect FDC-P1 and Yac-1 transfectants from a variety of apoptotic stimuli, the cells were not protected from cytolysis mediated by CTL from any of these sources, by NK cells, or granules isolated from CTL. However, Bcl-2 expression significantly inhibited apoptosis induced by purified granzyme B and perforin. These results suggest that while Bcl-2 is capable of inhibiting the apoptotic pathway utilized by perforin and granzyme B, other granule components can bypass this block. We conclude that CTL harbor potent killing mechanism(s) in addition to those provided by CD95 ligand or perforin and granzyme B that cannot be overcome by Bcl-2.
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PMID:Bcl-2 prevents apoptosis induced by perforin and granzyme B, but not that mediated by whole cytotoxic lymphocytes. 919 Sep 29

Bacterial RNases are promising tools for the development of anticancer drugs. Neoplastic transformation leads to enhanced accumulation of rRNA and tRNA, and altered expression of regulatory noncoding RNAs. Cleavage of RNA in cancer cells is the main reason for the cytotoxic effects of exogenic RNases. We have shown that binase, a cytotoxic ribonuclease from Bacillus intermedius, affects the total amount of intracellular RNA and the expression of proapoptotic and antiapoptotic mRNAs. For four cell lines, we visualized cellular RNA by fluorescence microscopy, and determined RNA levels, viability and apoptosis by flow cytometry. We found that the level of cellular RNA was decreased in cells that were sensitive to the cytotoxic effects of binase. The RNA level was lowered by 44% in HEK cells transfected with the hSK4 gene of the Ca(2+)-activated potassium channels (HEKhSK4) and by 20% in kit-transformed myeloid progenitor FDC-P1iR1171 cells. The most significant decrease in RNA levels was registered in the subpopulations of apoptotic cells. However, the binase-induced RNA decrease did not correlate with apoptosis. Kit-transformed cells with binase-induced RNA decrease retained viability if the interleukin-dependent proliferation pathway was activated. Using quantitative RT-PCR with RNA samples isolated from the binase-treated HEKhSK4 cells, we found that the amount of mRNA of the antiapoptotic bcl-2 gene in vivo was reduced about two-fold. In contrast, expression of the proapoptotic genes p53 and hSK4 was increased 1.5-fold and 4.3-fold, respectively. These results show that binase is a regulator of RNA-dependent processes of cell proliferation and apoptosis.
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PMID:Binase cleaves cellular noncoding RNAs and affects coding mRNAs. 1996 15

We recently reported that CMPD1, originally developed as an inhibitor of MK2 activation, primarily inhibits tubulin polymerisation and induces apoptosis in glioblastoma cells. In the present study we provide detailed pharmacological investigation of CMPD1 analogues with improved molecular properties. We determined their anti-cancer efficacy in glioblastoma cells with enhanced EGFR signalling, as deregulated EGFR often leads to chemoresistance. Eight analogues of CMPD1 with varying lipophilicity and basicity were synthesised and tested for efficacy in the cell viability assay using established glioblastoma cell lines and patient-derived primary glioblastoma cells. The mechanism of action for the most potent analogue 15 was determined using MK2 activation and tubulin polymerisation assays, together with the immunofluorescence analysis of the mitotic spindle formation. Apoptosis was analysed by Annexin V staining, immunoblotting analysis of bcl-2 proteins and PARP cleavage. The apoptotic activity of CMPD1 and analogue 15 was comparable across glioblastoma cell lines regardless of the EGFR status. Primary glioblastoma cells of the classical subtype that are characterized by enhanced EGFR activity were most sensitive to the treatment with CMPD1 and 15. In summary, we present mechanism of action for a novel small molecule tubulin inhibitor, compound 15 that inhibits tubulin polymerisation and mitotic spindle formation, induces degradation of anti-apoptotic bcl-2 proteins and leads to apoptosis of glioblastoma cells. We also demonstrate that the enhanced EGFR activity does not decrease the efficacy of tubulin inhibitors developed in this study.
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PMID:Pharmacology of novel small-molecule tubulin inhibitors in glioblastoma cells with enhanced EGFR signalling. 2651 52