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)

We have investigated apoptosis related gene expression in tumour cells, phenotype and function of blood mononuclear cells at diagnosis in relation to clinical response in three patients with nasopharyngeal carcinoma (NPC). We have focused our study on the Epstein Barr virus latent membrane protein-1 (LMP-1) and Bcl-2 expression in the tumour cells, the essential signal-transducing zeta molecule of T cell receptor (TcR zeta) and cellular mediated cytolysis of the blood mononuclear cells. The carcinoma cells of the patients were Bcl-2 negative. They were heterogeneous with regard to the expression of LMP-1 and the number of proliferating or apoptotic cells. Decrease in the expression of mature T cells (CD3, CD4, and CD8), TcR zeta and cellular mediated cytotoxicity was detected in blood mononuclear cells of the patients. IL-2 up-regulated these phenotypes and the cytolytic capacity of the blood mononuclear cells. The patient with LMP-1 negative carcinoma cells, down-regulated TcR zeta expression and impaired IL-2 mediated cytolysis, had the worst clinical outcome. Another patient with low apoptotic, highly proliferating and LMP-1 positive carcinoma cells had recurrent disease only in the irradiated area. Interestingly, NPC with high apoptotic and few LMP-1 expressing cells was detected in the patient with a normal level of TcR zeta expression and cytolytic functions in blood mononuclear cells at the time of diagnosis. After combination treatment with chemotherapy followed by radiotherapy, this patient is still alive with complete remission and disease-free at 36 months. Suppression of the immunological functions may occur in NPC patients. Our study suggests that the immunological functions and apoptosis related gene expression in the carcinoma cells may be used as prognostic factors and help in the decision of therapy of patients with nasopharyngeal cancer.
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PMID:Alteration of cellular mediated cytotoxicity, T cell receptor zeta (TcR zeta) and apoptosis related gene expression in nasopharyngeal carcinoma (NPC) patients: possible clinical relevance. 1081 Apr 2

During the early stages of thymopoiesis, cell survival is controlled by cytokines that regulate the expression of antiapoptotic proteins such as Bcl-2. At the pre-T cell stage, a critical checkpoint for beta chain selection is monitored by the tumor suppressor p53: pre-T cells can survive and differentiate when p53 is removed genetically or when its proapoptotic function is inactivated physiologically as a consequence of signaling through the pre-T cell receptor complex. Previous work has shown that the guanine nucleotide binding protein Rho controls cell survival in T cell progenitors. Here we define the survival pathways controlled by Rho in pre-T cells and show that this GTPase is a pivotal regulator of the p53-mediated checkpoint operating at the time of beta selection: loss of Rho function results in apoptosis in pre-T cells, but this cell death is prevented by loss of p53. The prevention of cell death by loss of p53 restored numbers of early T cell progenitors but did not fully restore thymic cellularity. Further analysis revealed that loss of Rho function caused survival defects in CD4/8 double-positive thymocytes that is independent of p53 but can be prevented by ectopic expression of Bcl-2. These studies highlight that the GTPase Rho is a crucial component of survival signaling pathways in at least two different thymocyte subpopulations: Rho controls the p53 survival checkpoint in pre-T cells and is also crucial for a p53 independent survival signaling pathway in CD4/8 double positives.
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PMID:The GTPase rho controls a p53-dependent survival checkpoint during thymopoiesis. 1088 May 28

Sera from healthy subjects receiving recombinant human granulocyte colony-stimulating factor (rHuG-CSF) to mobilize CD34(+) peripheral blood progenitors (PBPC) have been recently shown to induce unresponsiveness of allogeneic lymphocytes to mitogenic challenge. In the present investigation, the effects of rHuG-CSF on the early stages of lymphocyte activation-induced apoptosis and on lymphocyte cell cycle entry were evaluated. Sera were obtained from HLA-identical donors receiving rHuG-CSF to mobilize CD34(+) PBPC for allogeneic transplantation. Normal peripheral blood mononuclear cells (PBMC) were challenged with phytohemagglutinin (PHA) in the presence of serum collected before (preG) or after rHuG-CSF administration (postG). Mitochondrial function, that is, incorporation of 3,3'-dihexyloxacarbocyanine iodide [DiOC(6)(3)] and generation of reactive oxygen species (ROS) as well as expression of c-Myc and Bcl-2 family members (Bcl-2, Bcl-X(L), Bax) were evaluated by multiparameter flow cytometry. The activation-induced fragmentation of genomic DNA was detected by highly sensitive LM-PCR assay.CD4(+)DiOC(6)(3)(low) and CD8(+)DiOC(6)(3)(low) T lymphocytes increased and reached 32% (range 27%-38%) and 20% (range 15%-23%) of circulating T cells, respectively, on day 4 of rHuG-CSF administration. Hypergeneration of ROS could be demonstrated in 65% (range 58%-82%) of CD4(+) T lymphocytes and in 0.4% (range 0.2%-0. 8%) of circulating CD8(+) T cells. rHuG-CSF determined no alteration of mitochondrial function if added to allogeneic PBMC in vitro, thus suggesting indirect effects mediated by soluble factors; on the contrary, when PBMC were challenged with PHA in the presence of postG serum, both perturbation of mitochondrial transmembrane potential (Deltapsi(m)) and hypergeneration of ROS were induced, and lymphocytes were predominantly arrested in a G(0) -like phase of the cell cycle and displayed genomic DNA fragmentation. Interestingly, the preincubation of PBMC with a blocking antibody directed against CD95 abrogated the perturbation of lymphocyte Deltapsi(m), suggesting that the CD95 signaling pathway might play a role in the induction of apoptosis after PHA stimulation in the presence of postG serum. Moreover, Bax protein was overexpressed in postG (median fluorescence intensity = 180, range 168-186) compared with preG cultures (median fluorescence intensity = 75, range 68-80; p < 0.01), while no differences in Bcl-2, Bcl-X(L), and c-Myc staining intensity were observed. Our findings demonstrate a humoral-mediated rHuG-CSF-induced dissipation of lymphocyte mitochondrial Deltapsi(m); these effects might be mediated by Bax overexpression, with imbalance between apoptosis-promoting and apoptosis-inhibiting Bcl-2 family members and with subsequent induction of mitochondrial permeability transition. Whether immune dysfunction will favorably impact on incidence and severity of acute graft vs host disease after allogeneic PBPC transplantation remains to be determined.
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PMID:Granulocyte colony-stimulating factor perturbs lymphocyte mitochondrial function and inhibits cell cycle progression. 1088 Jul 47

In normal T-cell development, IL-7 plays a nonredundant role as an antiapoptic factor by regulating Bcl-2 expression in pro-T cells. In the current study, we addressed the roles of IL-7 and related cytokines as apoptosis-modulating factors in precursor T-cell acute lymphoblastic leukemia (T-ALL). To this end, leukemic blasts from pediatric patients with T-ALL were prospectively investigated as to their responsiveness to IL-7, IL-4, and IL-2 (in terms of modulation of spontaneous apoptosis, assessed by flow cytometry), cytokine receptor expression profiles, and expression levels of Bcl-2 and Bax proteins. IL-7, in contrast to IL-4 and IL-2, was highly efficient in apoptosis inhibition, and this effect correlated with the expression levels of IL-7Ralpha chain and with the up-regulation of Bcl-2 protein expression (P <.0001). Subclassification of T-ALL samples (n = 130) according to their in vitro IL-7 responses revealed that IL-7 refractory samples were more frequently positive for CD34 (P <.0001) and the myeloid-associated antigen CD33 (P =.01), whereas IL-7 responsiveness was associated with an expression of more mature differentiation-associated T-cell antigens (CD1a, surface CD3, CD4/8; P <.05). Furthermore, the extent of apoptosis inhibition by IL-7 in vitro quantitatively correlated with early cytoreduction as determined by the prednisone peripheral blood response on day 8 and cytoreduction in the marrow on day 15 (n = 87; P <.05). Multivariate analysis of the apoptosis-related parameters investigated, including spontaneous apoptosis, its inhibition by IL-7, and expression levels of Bcl-2 and Bax, showed that only IL-7 responsiveness has an independent impact on early cytoreduction (P <. 05), thus indicating a potential prognostic relevance of IL-7 sensitivity in T-ALL.
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PMID:Inhibition of in vitro spontaneous apoptosis by IL-7 correlates with bcl-2 up-regulation, cortical/mature immunophenotype, and better early cytoreduction of childhood T-cell acute lymphoblastic leukemia. 1089 65

CDR3 of the functional rearranged T-cell receptor variable beta region (TCR-Vbeta) transcript was sequenced in order to demonstrate for the first time the identity between a long-term cultured T-cell line derived from a cutaneous T-cell lymphoma (CTCL) patient and the malignant T-cell clone present in the blood. The patient's peripheral blood lymphocyte-derived cultured T-cell line had a CD3(+)Vbeta22(+)CD4(+)CD8alphaalpha(+)CD25(-) phenotype. It was named Pno and had been cultured for more than 1 year. Both fresh and long-term-cultured tumor cells proliferated highly in response to interleukin-7 (IL-7), and exogeneous IL-7 prevented Pno lymphocytes from apoptosis and maintained high levels of Bcl-2 expression. This unique malignant cloned lymphocyte line was further used to carry out functional studies. The results indicated that the CD3/TCR structures expressed by the Pno lymphocytes were functional because an immobilized anti-CD3 monoclonal antibody (mAb) or the combination of a soluble anti-CD3 mAb with submitogenic doses of phorbol 12 beta-myristate 13 alpha-acetate induced a proliferative response. Further, the CD2 and CD28 coreceptors were functional because they were able to induce a strong proliferative response upon their specific stimulation. Finally, the Pno T cell line had a Th3-type cytokine profile because it produced high amounts of the immunosuppressor cytokine tumor growth factor-beta1 (TGF-beta1). This high production of TGF-beta1 may inhibit antitumor specific responses in CTCL.
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PMID:Functional characterization of an IL-7-dependent CD4(+)CD8alphaalpha(+) Th3-type malignant cell line derived from a patient with a cutaneous T-cell lymphoma. 1091 Sep 22

Moloney murine leukemia virus (M-MuLV) is a replication-competent, simple retrovirus that induces T-cell lymphomas when inoculated into neonatal mice. The tumor cells are typically derived from immature T cells. During preleukemic times, a marked decrease in thymic size is apparent in M-MuLV-inoculated mice. We previously demonstrated that this thymic regression is correlated with enhanced levels of thymocyte apoptosis (C. Bonzon and H. Fan, J. Virol. 73:2434-2441, 1999). In this study, we investigated the apoptotic state of M-MuLV-induced tumors. M-MuLV-induced tumors were screened for expression of the apoptotic proteins Fas and Bcl-2 by three-color flow cytometric analysis. Single-positive (SP; CD4(+) CD8(-) and CD4(-) CD8(+)) tumor cells generally displayed lower cell surface expression of Fas than SP thymocytes from uninoculated control mice. Double-positive (DP; CD4(+) CD8(+)) M-MuLV-induced tumor cells fell into two categories: those with normal high levels of Fas and those with low levels of Fas. Additionally, the vast majority of DP tumors showed elevated Bcl-2 levels. The DP tumor cells retaining normal/high Fas expression were capable of transducing an apoptotic signal upon anti-Fas engagement. In addition, DP and CD4(+) SP tumor populations displayed higher levels of Fas ligand than normal thymocytes with the same phenotypes. In contrast, CD8(+) SP and CD4(-) CD8(-) tumors did not show elevated Fas ligand expression. There was no significant correlation between Fas and Fas ligand expression in the DP tumors, suggesting that Fas Ligand expression was not the driving force behind Fas down-regulation. These results suggest that both the Fas death receptor and mitochondrial pathways of apoptotic death are active in M-MuLV-induced tumors and that they must be modulated to permit cell survival and tumor outgrowth.
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PMID:Moloney murine leukemia virus-induced tumors show altered levels of proapoptotic and antiapoptotic proteins. 1093 26

The present study investigates the role of the HIV-suppressive beta-chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1 and RANTES in activation-induced cell death (AICD). A pool of these beta-chemokines reduced anti-CD3-induced apoptosis of T cell blasts from healthy blood donors in a dose-dependent manner. Although the pooled beta-chemokines were more effective, the inhibitory effect could also be mediated by each of the individual chemokines and was blocked by neutralizing anti-chemokine antibodies. The beta-chemokines also inhibited pokeweed mitogen/staphylococcal enterotoxin B-induced T lymphocyte apoptosis in 33/49 HIV-infected (HIV+) individuals. This anti-apoptotic effect was not correlated with the patients' CD4 T cell counts. beta-chemokines did not lead to altered secretion of IL-2, IL-4, IFN-gamma or IL-10 in response to activation stimuli in either normal T cell blasts or peripheral blood mononuclear cells from HIV+ individuals. Co-incubation with beta-chemokines did not inhibit anti-CD3-induced expression of cell surface Fas ligand, nor did it alter levels of the death receptor Fas or Bcl-2 in T cell blasts, suggesting that the beta-chemokines are blocking AICD downstream of Fas. These observations indicate that beta-chemokines may play a novel role as modulators of AICD, in addition to their known role as chemoattractants and inhibitors of HIV replication.
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PMID:Beta-chemokines inhibit activation-induced death of lymphocytes from HIV-infected individuals. 1094 Aug 94

Chlorambucil and other cytotoxic drugs kill cells, non-selectively, by inducing apoptosis. In this study, we measured the apoptotic response to chlorambucil in T- and B-cells from untreated B-CLL patients and T-cells, from normal control subjects. We found increased chemosensitivity in the T-cells of B-CLL patients compared to the controls (P=0.0002). The chlorambucil ID(50) values for T-cells from B-CLL patients showed a direct correlation with Bcl-2 expression (P=0.002) and an inverse correlation with CD3 cell count (P<0.0001), suggesting a trend of increasing chemosensitivity and decreasing Bcl-2 expression with an elevated T-cell count. There was no differential expression of Bcl-2 or Bax between the CD4(+) and CD8(+) cells of B-CLL patients, isolated by immunomagnetic separation. We found correlations in the leukaemic B-cells between chlorambucil ID(50) values and both Bcl-2 expression (P=0.006), and Bcl-2/Bax ratios (P=0.002), suggesting a role for the Bcl-2/Bax ratio in predicting the response of untreated CLL patients to cytotoxic treatment. Chlorambucil produced almost identical changes in Bcl-2 and Bax expression in normal T-cells and leukaemic B-cells triggered to die by apoptosis, which together with the correlation between Bcl-2 and chemosensitivity confirms a pivotal role for Bcl-2 in regulating a distal step in the apoptotic pathway following cytotoxic cellular damage.
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PMID:Bcl-2 and bax expression and chlorambucil-induced apoptosis in the T-cells and leukaemic B-cells of untreated B-cell chronic lymphocytic leukaemia patients. 1099 99

It has been observed that the progressive ascitic growth of a transplantable T cell lymphoma of spontaneous origin, designated as Dalton's lymphoma (DL), induces inhibition of various immune responses and is associated with an involution of the thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes, with a decrease in CD4+CD8+, CD4+CD8- and CD4-CD8+ thymocytes. Morphological evaluation of thymocytes from DL-bearing mice revealed that with the progression of DL, a majority of thymocytes exhibited morphological features characteristic of apoptotic cell death, which included contracted cell bodies, condensed, uniformly circumscribed and densely stained chromatin, and membrane-bound apoptotic bodies containing one or more nuclear fragments. Quantitative and qualitative analysis of the DNA extracted from the thymocytes of DL-bearing mice revealed DNA fragmentation that increased concomitantly with the progression of DL and showed an oligonucleosomal DNA ladder pattern upon agarose gel electrophoresis, a hallmark of apoptotic cell death. Attempts to identify apoptotic factor(s) showed that the serum of DL-bearing mice contained certain soluble factor(s) that augmented the induction of apoptotis in thymocytes in a time- and dose-dependent manner. Although DL cells or their products, such as DL-cell-conditioned medium or DL-cell-free ascitic fluid, could also induce apoptosis of thymocytes in vitro, the magnitude of the same was consistently lower than that induced by the serum of DL-bearing mice. Further, elucidation of the mechanism of apoptosis induction in thymocytes with respect to the involvement of apoptosis-related genes revealed that the death pathway followed an interleukin-1 beta-converting-enzyme-dependent, Fas-mediated apoptotic cascade, with a concomitant increase in the protein products of the bax, bad, p53, fas and fasL genes and cleavage of the 23-kD N-terminal fragment of Bcl-2 that exhibited Bax-like death effector properties.
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PMID:Ascitic growth of a spontaneous transplantable T cell lymphoma induces thymic involution. 2. Induction of apoptosis in thymocytes. 1100 72

beta-Adrenergic receptor (betaAR) activation and/or increases in cAMP regulate growth and proliferation of a variety of cells and, in some cells, promote cell death. In the current studies we addressed the mechanism of this growth reduction by examining betaAR-mediated effects in the murine T-lymphoma cell line S49. Wild-type S49 cells, derived from immature thymocytes (CD4(+)/CD8(+)) undergo growth arrest and subsequent death when treated with agents that increase cAMP levels (e.g., betaAR agonists, 8-bromo-cAMP, cholera toxin, forskolin). Morphological and biochemical criteria indicate that this cell death is a result of apoptosis. In cyc(-) and kin(-) S49 cells, which lack G(s)alpha and functional protein kinase A (PKA), respectively, betaAR activation of G(s)alpha and cAMP action via PKA are critical steps in this apoptotic pathway. S49 cells that overexpress Bcl-2 are resistant to cAMP-induced apoptosis. We conclude that betaAR activation induces apoptosis in immature T lymphocytes via G(s)alpha and PKA, while overexpression of Bcl-2 prevents cell death. betaAR/cAMP/PKA-mediated apoptosis may provide a means to control proliferation of immature T cells in vivo.
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PMID:beta-adrenergic receptor/cAMP-mediated signaling and apoptosis of S49 lymphoma cells. 1102 15


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