Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have analyzed phenotypic, functional, and molecular properties of B-chronic lymphocytic leukemia (B-CLL) cells as compared to normal B cell differentiation stages and/or subsets. The possibility that the target B cell population transformed by the I primary oncogenic event(s) belongs to the normal CD5+ B cell subset from B mantle zone of secondary follicles is highly likely on phenotypic grounds. Though the genes responsible for the primary oncogenic event are presently unknown, a number of functional and molecular findings indicate that the end-product of their transforming activity is a cell frozen in the G0 phase of the cell cycle. This cell has several abnormalities that prevent an appropriate mitogenic response and presents a pattern of apoptosis-related gene expression that hinders apoptotic death. Pivotal to this apoptosis-escaping capacity is the expression of Bcl-2. We suggest that the increased expression of Bcl-2 together with an asynchronism between the expression of Bcl-2, c-myc, and APO1/Fas gene products shift the cellular balance away from apoptosis thereby helping the progressive accumulation in G0 of malignant CD5+ B cells.
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PMID:The nature of the B lymphocyte in B-chronic lymphocytic leukemia. 751 20

A number of apoptosis-inducing agents used in cancer therapy (etoposide, doxorubicin, 1-beta-D-arabinofuranosylcytosine), as well as the proapoptotic second messenger ceramide, induce a disruption of the mitochondrial transmembrane potential (delta psi m) that precedes nuclear DNA fragmentation. This effect has been observed in tumor cell lines of T-lymphoid, B-lymphoid, and myelomonocytic origin in vitro. Circulating tumor cells from patients receiving chemotherapy in vivo also demonstrate a delta psi m disruption after in vitro culture that precedes nuclear apoptosis. Transfection-enforced hyperexpression of the proto-oncogenes bcl-2 and bcl-XL protects against chemotherapy-induced apoptosis, at both the level of the mitochondrial dysfunction preceding nuclear apoptosis and the level of late nuclear apoptotic events. Bcl-2-mediated inhibition of ceramide-induced delta psi m disruption is observed in normal as well as anucleate cells, indicating that bcl-2 acts on an extranuclear pathway of apoptosis. In contrast to Bcl-2 and Bcl-XL, hyperexpression of the protease inhibitor cytokine response modifier A fails to protect tumor cells against chemotherapy-induced delta psi m disruption and apoptosis, although cytokine response modifier A does prevent the delta psi m collapse and posterior nuclear apoptosis triggered by cross-linking of Fas/Apo-1/CD95. In conclusion, delta psi m disruption seems to be an obligatory step of early (pre-nuclear) apoptosis, and delta psi m is stabilized by two members of the bcl-2 gene family conferring resistance to chemotherapy.
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PMID:Bcl-2 and Bcl-XL antagonize the mitochondrial dysfunction preceding nuclear apoptosis induced by chemotherapeutic agents. 898 42

The adenovirus (Ad) 14.7-kDa E3 protein (E3-14.7K), which can inhibit tumor necrosis factor alpha (TNF-alpha) cytolysis, was used to screen HeLa cell cDNA libraries for interacting proteins in the yeast two-hybrid system. A new member of the low-molecular-weight (LMW) GTP-binding protein family with Ras and ADP-ribosylation factor homology was discovered by this selection and has been named FIP-1 (14.7K-interacting protein). FIP-1 colocalized with Ad E3-14.7K in the cytoplasm especially near the nuclear membrane and in discrete foci on or near the plasma membrane. Its interaction with E3-14.7K was dependent on the FIP-1 GTP-binding domain. The stable expression of FIP-1 antisense message partially protected the cells from TNF-alpha cytolysis. FIP-1 was associated transiently with several unknown phosphorylated cellular proteins within 15 min after treatment with TNF-alpha. FIP-1 mRNA was expressed ubiquitously but at higher levels in human skeletal muscle, heart, and brain. In addition to homology to other LMW GTP-binding proteins, FIP-1 has regions of homology to two prokaryotic metalloproteases. However, there was no homology between FIP-1 and any of the recently isolated death proteins in the TNF-alpha or Fas/APO1 cytolytic pathway and no interaction with several members of the Bcl-2 family of inhibitors of apoptosis. These data suggest that FIP-1, as a cellular target for Ad E3-14.7K, is either a new intermediate on a previously described pathway or part of a novel TNF-alpha-induced cell death pathway. FIP-1 has two consensus sequences for myristoylation which would be expected to facilitate membrane association and also has sequences for Ser/Thr as well as Tyr phosphorylation that could affect its function.
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PMID:Interaction of an adenovirus 14.7-kilodalton protein inhibitor of tumor necrosis factor alpha cytolysis with a new member of the GTPase superfamily of signal transducers. 899 84

Breast tumor cells are relatively refractory to apoptosis in response to modalities which induce DNA damage such as ionizing radiation and the topoisomerase II inhibitor, adriamycin. Various factors which may modulate the apoptotic response to DNA damage include the p53 status of the cell, levels and activity of the Bax and Bcl-2 families of proteins, activation of NF-kappa B, relative levels of insulin like growth factor and insulin-like growth factor binding proteins, activation of MAP kinases and PI3/Akt kinases, (the absence of) ceramide generation and the CD95 (APO1/Fas) signaling pathway. Prolonged growth arrest associated with replicative senescence may represent an alternative and reciprocal response to DNA-damage induced apoptosis that is p53 and/or p21waf1/cip1 dependent while delayed apoptosis may occur in p53 mutant breast tumor cells which fail to maintain the growth-arrested state. Clearly, the absence of an immediate apoptotic response to DNA damage does not eliminate other avenues leading to cell death and loss of self-renewal capacity in the breast tumor cell. Nevertheless, prolonged growth arrest (even if ultimately succeeded by apoptotic or necrotic cell death) could provide an opportunity for subpopulations of breast tumor cells to recover proliferative capacity and to develop resistance to subsequent clinical intervention.
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PMID:Growth arrest and cell death in the breast tumor cell in response to ionizing radiation and chemotherapeutic agents which induce DNA damage. 1107 87

Jurkat T cells showed a major, early decrease in blue autofluorescence in response to Fas/Apo-1/CD95 cross-linking or stimulation with cell-permeant ceramide. This indicates the oxidation/depletion of NADH or NADPH before the onset of apoptosis. Kinetic studies, cytofluorimetric multiparameter analyses and cell sorting experiments indicated a close temporal relationship between NAD(P)H oxidation/depletion and the dissipation of the mitochondrial transmembrane potential (DeltaPsi(m)). In contrast, NAD(P)H depletion was detected well before several other changes associated with late apoptosis, including enhanced superoxide generation, phosphatidylserine exposure on the cell surface, loss of cytosolic K(+), decreased cytoplasmic pH, nuclear DNA fragmentation, cell shrinkage, loss of viability and the appearance of the mitochondrial antigen APO2.7. Full activation of caspase 9 and caspase 3 appeared to be correlated with the appearance of superoxide anions in the mitochondria, and followed the drop in NADPH. Overexpression of the apoptosis-inhibitory proto-oncogene Bcl-2, which encodes an inhibitor of the mitochondrial permeability transition (PT) pore, delayed both the DeltaPsi(m) disruption and the depletion of NAD(P)H. Similar effects were observed with the pharmacological PT pore inhibitors, bongkrekic acid and cyclosporin A. Thus there appears to be a close functional relationship between mitochondrial and cellular redox changes during early apoptosis; events that are inhibited by Bcl-2.
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PMID:Oxidation of pyridine nucleotides during Fas- and ceramide-induced apoptosis in Jurkat cells: correlation with changes in mitochondria, glutathione depletion, intracellular acidification and caspase 3 activation. 1113 1

B-cell chronic lymphocytic leukemia (B-CLL) follows heterogeneous clinical courses, and several biological parameters need to be added to the current clinical staging systems to predict which patients will experience an indolent or an aggressive outcome. This study analyzed CD38 expression by flow cytometry and soluble APO1/Fas (sAPO1/Fas), Bcl-2 (sBcl-2), and CD23 (sCD23) proteins by immunoenzymatic methods to evaluate their effect on the clinical course of 168 unselected B-CLL patients. Intermediate/high risk modified Rai stages were characterized by a higher CD38(+) B-cell number (P =.0002) and higher sCD23 levels (P <.0001). Moreover, CD38(+) B-cell percentages were significantly and directly associated both with beta(2)-microglobulin and sCD23 concentrations (P <.0001 and P =.002, respectively). Both a higher tumor burden (lymphadenopathy/splenomegaly) and a lymphocyte doubling time less than 12 months were significantly associated with higher CD38(+) percentages (P <.0001 and P =.0001, respectively). With regard to clinical outcome, progression-free survival was significantly longer (75% versus 37% at 5 years; P =.00006) in patients with lower CD38(+) B-cell percentages. Furthermore, the risk of partial or no response to fludarabine increased with increasing CD38 expression (P =.003), and a shorter overall survival (50% versus 92% at 8 years; P <.00001) characterized patients with more than 30% CD38(+) B-cell number. The predictive value of CD38 expression was maintained among the patients within the Rai intermediate risk group and was confirmed in multivariate analysis. Thus, the percentage of CD38(+) B cells appears to be an accurate predictor of clinical outcome and therefore could be used to indicate when more novel chemotherapeutic approaches are needed.
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PMID:Clinical significance of CD38 expression in chronic lymphocytic leukemia. 1167 31

Resistance to apoptosis may be related to tumor progression, due to the implications it might have on both tumor mass and genetic instability. We compared the tendency to spontaneous apoptosis and the proliferative capacity of metastatic growths of several AKR lymphoma variants (TAU-45, TAU-47, TAU-44, TAU-33, TAU-42 and TAU-46, in the order of increasing metastatic potential). We further compared the expression of several apoptosis-related genes. Cell proliferative capacity did not appear to determine malignant behavior since, on the whole, a decrease in S + G2M fraction was observed with increasing malignancy. Sensitivity to apoptotic cell death decreased with increasing malignancy when comparing the TAU-45, TAU-47, TAU-44 and TAU-33 variants, suggesting a role of reduced apoptosis in this T-cell lymphoma. An increase in Bcl-2 content with increasing aggressiveness among these variants, implicates this protein in this tumor progression-related resistance to apoptosis. However, the two variants of highest malignancy, TAU-42 and TAU-46, did not follow the same trend, since they displayed a relatively high content in apoptotic cells and a low Bcl-2 content. Fas receptor expression did not correlate with tendency to apoptosis, indicating that malignant behavior in the AKR lymphoma does not depend on CD95/Fas/APO1 downregulation. Overexpression of p53 was observed only in one of the variants of lowest malignancy.
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PMID:Apoptotic cell death and related gene expression in metastatic tumors of AKR lymphomas of varying malignancy. 1463 27

Transformation of leukemic cells is associated with delay in maturation and in apoptosis, and to altered responsiveness to growth factors. However, some studies have revealed that Fas (CD95/APO1) which mediates apoptotic signal and decrease of anti-apoptotic Bcl-2 are frequently observed in acute myeloid leukemia (AML) M4/M5 leukemic cells. The aim of the study was to compare cytomorphology and cytochemistry of bone marrow (BM) apoptotic leukemic cells to preserved peripheral blood (PB) leukemic cells in our patient, a 76-year-old man with AML-M5b treated at Zagreb University Hospital Center. BM and PB of the AL patient were analyzed after Pappenheim and cytochemical stainings, and leukemic cells were classified according to FAB and WHO classification. Analysis of PB revealed leukocytosis and 80-90% monocytic cells (46% monoblasts, 29% promonocytes and 11% monocytes). Only a few preserved monoblasts and promonocytes were found in BM, together with numerous morphologically altered cells with characteristic chromatin condensation and pyknosis of nucleus, as well as nuclear fragmentation and formation of apoptotic bodies. Thus, cytomorphology of PB leukemic cells pointed to proliferation of immature monocytic cells, and cytomorphology of BM to cell apoptosis. Cytochemistry of PB monocytic cells and BM apoptotic cells confirmed monocytic cell lineage because esterase was strongly positive in almost all BM apoptotic leukemic cells and PB leukemic cells, and esterase was completely inhibited with sodium fluoride. On the basis of these findings, AML-M5b was diagnosed in our patient. There are many possible explanations for our observation of BM leukemic cell apoptosis in a patient with AML-M5. The most reliable one is that apoptosis was induced ex vivo after BM aspiration in course of the air drying of BM specimen before staining. Mass BM leukemic cell apoptosis that was recorded in contrast to numerous preserved leukemic cells in PK could be probably connected to unfavorable ratio of relatively low concentration of cytokines in relation to high leukemic cell number in BM aspirated cytologic specimen.
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PMID:Apoptosis of leukemic cells: a case report. 2069 59