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)

B-cell chronic lymphocytic leukemia (CLL) is characterized by profound immune dysfunction and a marked resistance to apoptosis. Understanding the cellular biology of immune effector cells from CLL patients as well as leukemic target cells is essential to developing immune mediated therapeutic strategies for CLL. In this study, an immortal CLL cell line called WSU-CLL has been used to study the characteristics of B-cell CLL as a tumor target for natural killer (NK), activated natural killer, and lymphokine activated killer (LAK) cells. The WSU-CLL cells were significantly less (p<0.001) susceptible to NK cell mediated cytotoxicity compared to K562, a standard tumor target cell line. In vitro activation of effector cells with either short term, low dose IL-2 or long term, high dose IL-2 significantly increased the susceptibility of CLL cells for cell mediated killing. The addition of CD1a+/CD3-/CD4+/CD80+/CD83+ dendritic cells derived from human umbilical cord blood increased the cytotoxicity of LAK cells against WSU-CLL. There is an increased expression of Bcl-2 and decreased expression of Fas on WSU-CLL cells as determined by RT-PCR techniques indicating possible roles for these genes in exerting resistance to immune cell mediated lysis. When Bcl-2 expression was downregulated in WSU-CLL cells using gene specific antisense oligonucleotides, the susceptibility of WSU-CLL cells to the cytotoxicity of chemotherapeutic agent Fludarabine was increased. Thus, our results suggest that in vitro activation with cytokines, addition of accessory cell populations such as dendritic cells and/or manipulation of key gene expression i.e. down regulation of Bcl-2 might be potential strategies to increase the antitumor cytotoxicity against CLL cells.
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PMID:Increased cytotoxicity against B-chronic lymphocytic leukemia by cellular manipulations: potentials for therapeutic use. 1134 40

A large proportion of B-chronic lymphocytic leukaemia (B-CLL) cells express the anti-apoptotic protein Bcl-2. Basic fibroblast growth factor (bFGF) has been shown to upregulate the expression of Bcl-2 in B-CLL cell lines. Vascular endothelial growth factor (VEGF) has been shown to enhance the survival of endothelial cells by upregulating the expression of Bcl-2. In the present study, we measured serum and cellular levels of bFGF and VEGF in 85 patients with CLL using a commercial quantitative sandwich enzyme immunoassay technique. Levels of Bcl-2 were also assayed concomitantly using Western blot analysis. The mean serum level of bFGF was 53.4 pg/ml (range 0-589) and that of VEGF 459.2 pg/ml (range 33-1793). The mean cellular level of bFGF was 158.3 pg/2 x 105 cells (range 0.8-841) and VEGF, 42.4 pg/2 x 105 cells (range 0-244). A high correlation was found between serum and cellular bFGF levels (P < 0.001), but not between the corresponding VEGF levels. Twenty-nine of 69 patients (42%) evaluated for Bcl-2 level, expressed it. The Bcl-2 level was positively correlated with the serum bFGF level (P = 0.007). However, surprisingly there was a negative correlation between Bcl-2 expression and intracellular VEGF level (P = 0.003). A positive correlation was also found between serum bFGF and disease follow-up time and log white blood cell count. These findings indicate that in CLL there is a correlation between angiogenesis-related factors and apoptosis-related protein expression, and elevated bFGF levels may account for the elevated Bcl-2 levels.
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PMID:Bcl-2 expression correlates positively with serum basic fibroblast growth factor (bFGF) and negatively with cellular vascular endothelial growth factor (VEGF) in patients with chronic lymphocytic leukaemia. 1138 Apr 5

In this review, we summarize the morphological features and immunophenotypic profile of chronic lymphocytic leukemia (CLL) cells, discuss the value of these investigations as front line diagnostic tests, and emphasize their correlation with the clinical features, disease progression, molecular genetics and pathogenesis of CLL. In CLL, the morphology of the circulating cells is characteristic and typical in the majority of cases. However, 15% of patients, either at diagnosis or during the course of the disease, show atypical morphology reflected by either (1) an increased (> 10%) number of circulating prolymphocytes, designated CLL/PL, or (2) an increased (> 15%) number of circulating lymphoplasmacytic and cleaved cells, designated 'atypical' CLL. There is strong evidence of a close association between atypical morphology (CLL/PL) and atypical (CLL) and clinical features, e.g. disease progression, advanced stage and survival, molecular genetics, particularly trisomy 12, but also the rare cases with t(11;14) or t(14;19), p53 abnormalities, unmutated immunoglobulin (Ig) VH genes and origin of the cell (naive, pregerminal center cell). CLL cells have a distinct immunological repertoire different from that of other lymphoproliferative disorders. The typical CLL phenotype is CD5+, CD23+, FMC7-, weak expression of surface Ig (sIg) and weak or absent expression of membrane CD22 and CD79b. The latter marker identifies an extracellular epitope of the B-cell receptor (BCR) beta chain and its weak or absent expression in CLL may derive from the expression of a truncated form. This, together with the low expression of CD22, might explain the abnormal signal transduction of CLL cells similar to that of anergic B lymphocytes. Because no single marker is specific for CLL, a composite phenotype considering this set of 5 or 6 markers compounded into a scoring system helps to distinguish CLL from the other B-cell malignancies. Immunophenotypic analysis has also been shown to be useful for minimal residual disease detection and adds valuable prognostic information because the expression of certain markers, such as FMC7 or CD38, seems to be associated with a poor outcome. In addition, CLL cells express a variety of Bcl-2 family proteins with a profile that favors inhibition of apoptosis which, together with the interaction with microenvironmental (e.g. stromal) cells and the release of cytokines, explains the long life span and subsequent accumulation of CLL cells in various organs. Despite controversies relating to the expression of adhesion molecules (selectins and integrins) in CLL cells, it appears that some of these molecules do play a role in the pathogenesis, biology and clinical patterns of the disease. In conclusion, morphology and immunophenotype are the two essential investigations, which must be carried out in all cases of CLL. Both provide relevant information in terms of diagnosis, course of the disease, prognosis and pathogenesis.
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PMID:Morphological and immunophenotypic features of chronic lymphocytic leukemia. 1148 29

Genasense (formerly known as G-3139), an antisense oligonucleotide specific for Bcl-2, is under development by Genta as an iv drip infusion for the potential treatment of various cancers including melanoma, prostate, breast and colon cancer [3083751. It is in phase III trials for malignant melanoma, for which it has been awarded Fast Track status 1359044]. Genasense received Orphan Drug status in August 2000 [3782331. In September 2000, the company announced that pivotal phase III trials in multiple melanoma, chronic lymphocytic leukemia (CLL) and acute myelocytic leukemia (AML) would be underway by 2001 [382783]. By January 2001, trials in AML and CLL had been initiated 1396512]. As of February 2001, Genta was planning the initiation of two additional, registration quality trials. Pending positive results from these trials, launch of Genasense is anticipated in 2002 13984111. A phase III trial in patients with advanced multiple myeloma at 65 centers in the US, Canada and Great Britain began in February 2001. The trial will examine whether the addition of Genasense can improve response rates, response duration and quality of life compared with dexamethasone therapy alone 13989081. Genta Inc has been issued a patent (US-05831066) for Genasense 1283005]. The patent provides protection to Genta for the composition of Genasense and its analogs. Furthermore, Genta Inc has also been issued two new patents that cover a series of compounds containing new backbone constructions that enhance the antisense affinity of the drug to the target pre-RNA, while the other patent covers the methods for preparation of antisense oligonucleotides containing the new backbone structures 12896851. Genta has already licensed the rights for the use of Bd-2 as a target for antisense- and gene therapy-based treatments from The University of Pennsylvania. The licensing agreements with Chugai Pharmaceutical Co for worldwide marketing and profit sharing places Genta in a favorable position. In January 2001, Needham & Co expected Genasense to have a potential market of 47,700 malignant melanoma patients in the US. The analysts also expected potential patient market sizes of 50,000 (CLL), 21,000 (AML), 136,000 (non-small cell lung cancer; NSLCC) and 180,000 (prostate cancer) in the US. In addition, the analysts predicted that Genasense would be approved for melanoma in the second quarter of 2002, with approvals to follow for CLL (third quarter of 2002), AML (third quarter of 2002) and myeloma (fourth quarter of 2002) 1399251].
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PMID:Genasense (Genta Inc). 1156 20

Malignant B cells from chronic lymphocytic leukemia (B-CLL) patients have a long survival in vivo, although, in culture, they spontaneously die by apoptosis. Here, we analyzed the capacity of accessory leukocytes to modulate apoptosis of B-CLL cells in vitro. To this end, we performed long-term cultures using total mononuclear cells (TMC) from B-CLL patients and TMC depleted from monocytes, NK cells and T lymphocytes (B-CLL cells). In all the patients studied (n = 25) the presence of accessory leukocytes markedly prolonged the survival of B-CLL cells. The anti-apoptotic effect was exerted by monocytes and, to a lesser degree, NK cells, partially through the release of soluble factors. Indeed, accessory leukocytes separated from leukemic cells by semipermeable membranes were still able to prolong B-CLL cell survival. By flow cytometric analysis we found that the protective effect of non-malignant cells was associated with delayed down-regulation of Bcl-2 expression on leukemic cells. By contrast, the expression of Fas and Fas ligand proteins was unchanged in most samples. Our findings suggest that monocytes and NK cells, by delaying leukemic cell apoptosis, may play a role in B-CLL cell accumulation in vivo.
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PMID:Non-malignant leukocytes delay spontaneous B-CLL cell apoptosis. 1175 6

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent activator of the cell death pathway and exerts tumoricidal activity in vivo with minimal toxicity. In order to investigate the therapeutic potential of TRAIL in B chronic lymphocytic leukemia (B-CLL) we have analyzed the expression of TRAIL receptors (TRAIL-Rs) in leukemic cells from B-CLL patients and their in vitro sensitivity to apoptosis induced by recombinant human TRAIL. We have found TRAIL-R1 and -R2 death receptor, and TRAIL-R3 and -R4 decoy receptor mRNA expression in most of the 57 B-CLL patients studied (R1 82%, R2 100%, R3 96% and R4 82%). TRAIL-R1 and R2 proteins were expressed on the surface and within the cells, whereas R3 and R4 decoy receptors were almost exclusively expressed in the cytoplasm. Despite TRAIL death receptor expression, B-CLL cells were relatively resistant to induction of apoptosis by recombinant human TRAIL (300 ng/ml). However, the susceptibility to TRAIL-induced apoptosis was increased by treatment of B-CLL cells with actinomycin D (Act D). Western blot analysis showed higher constitutive expression of the long form of FLICE-inhibitory protein (FLIP(L)) in B-CLL as compared to normal tonsillar B cells. Act D treatment down-regulated both long and short FLIP expression, which was correlated with the increase in B-CLL sensitivity to TRAIL. Although the surface TRAIL death receptor expression was up-regulated both by cell culture and by Act D treatment, the changes were not correlated with a gain in susceptibility to TRAIL. In addition, neither decoy receptors nor Bcl-2 expression were affected by Act D. Our findings suggest the possible involvement of FLIP in regulating TRAIL-mediated apoptosis in B-CLL.
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PMID:Sensitization to TRAIL-induced apoptosis and modulation of FLICE-inhibitory protein in B chronic lymphocytic leukemia by actinomycin D. 1175 7

Signal transduction and apoptosis in B-cell chronic lymphocytic leukemia (CLL) cells with a post-germinal center (GC) phenotype were studied. Specific activation of the cells was induced by a combination of soluble anti-CD40 monoclonal antibody and interleukin-4 (CD40/IL-4) and nonspecific activation with a combination of phytohemagglutinin, phorbol-12-myristate-13-acetate and ionomycin (chemical mixture). Less than 5% of these leukemia cells entered the cell cycle after activation, as indicated by the number of cells in G0/G1 phase. The protein tyrosine phosphorylation pattern and expression of the Bcl-2 protein were specific in ex vivo CLL cells of each individual patient. Expression of the p53 protein was not detectable in these leukemia cells. Cross-linking of the CD40/IL-4 receptors on CLL cells significantly upregulated phosphotyrosine proteins and the p53 protein. In the presence of chemical mixture, downregulated phosphotyrosine proteins were detected. Alterations in Bcl-2 expression were independent of cross-linking with CD40/IL-4 or chemical mixture. A high frequency of apoptotic cells was detected in cells that had downregulated phosphotyrosine proteins and Bcl-2 protein. There was no correlation between induction of apoptosis and expression of p53 protein. Our results suggest that apoptosis in resting leukemia cells could occur prior to the cell cycle progression. Alterations in phosphotyrosine proteins and Bcl-2 but not p53 might play an important role in the regulation of apoptosis in resting G0/G1 memory post-GC B-CLL cells.
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PMID:Significance of phosphotyrosine proteins, Bcl-2 and p53 for apoptosis in resting B-chronic lymphocytic leukemia (CLL) cells. 1177 86

Although B chronic lymphocytic leukemia (B-CLL) is characterized by prolonged survival of CD5(+) B cells in vivo, these cells apoptose spontaneously in vitro. The effect of CD5 ligation on apoptosis was studied in 27 newly diagnosed patients with B-CLL, in relation to the expression of surface IgM (sIgM), CD79b, CD38, CD72 and CD19. B cells from 15 patients (group I) were resistant to anti-CD5-induced apoptosis, whereas apoptosis above spontaneous levels was seen in the remaining 12 studied (group II). Group II was then subdivided on the basis of differences in the time required to reach maximum apoptosis: whilst B cells from seven patients underwent apoptosis by 18 h, those from the remaining five needed 36 h to apoptose. The expression of sIgM, CD5, CD79b and CD38 was higher in group II than group I, suggesting that signaling for apoptosis might operate via CD79, and that CD38 expression was required. As shown by flow cytometry and confirmed by Western blotting, apoptosis was associated with a decrease in the ratios of Bcl-2/Bax and Bcl(XL)/Bax, due to an increase in the level of Bax, but no change in that of Bcl-2. This heterogeneous apoptotic response to CD5 ligation offers an explanation for the incomplete success of anti-CD5 monoclonal therapy, and might help identify patients who would respond to such treatment.
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PMID:CD5-induced apoptosis of B cells in some patients with chronic lymphocytic leukemia. 1184 Feb 62

We evaluated the presence of P-glycoprotein (P-gp)-170, multidrug resistance protein (MRP), lung resistance protein (LRP)-56 and Bcl-2 in CD19-positive cells from 100 cases of chronic lymphocytic leukaemia (CLL). P-gp-170 was found in 73% of the CLL cases with no significant difference regarding stage or previous treatment. LRP-56 protein was homogeneously distributed with no differences for stage or treatment. MRP protein was detected at a low level of expression in 49.4% of CLL patients with no differences for stage or treatment. Bcl-2 protein was expressed at a high level in all CLL patients and higher levels were found in the advanced stage. This leads us to conclude that P-gp, MRP, LRP-56 and Bcl-2 are frequently expressed in CLL. P-gp, MRP and LRP are not correlated to stage or previous treatment. Bcl-2 is higher in advanced-stage patients. The clinical and biological significance of these zMDR mechanisms in CLL remains to be fully explained.
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PMID:Multidrug resistance mechanisms in chronic lymphocytic leukaemia. 1188 80

In B-CLL, non-proliferating B cells accumulate due to defective apoptosis. Cytotoxic therapies trigger apoptosis and deregulation of apoptotic pathways contributes to chemoresistance. Loss of the apoptosis-promoting Bax has been implicated in resistance to cytotoxic therapy. We therefore evaluated ex vivo drug sensitivity of CLL, producing chemoresponse data which are prognostic indicators for B-CLL, in particular in the case of purine nucleoside analogs. To analyze the underlying mechanisms of drug resistance, we compared endogenous Bax and Bcl-2 expression to ex vivo response to eight drugs, and to survival in 39 B-CLL patients. We found that reduced Bax levels correlated well with ex vivo resistance to traditional B-CLL therapies - anthracyclines, alkylating agents and vincristine (all P < 0.04). Surprisingly, no such relationship was observed for the purine nucleoside analogs or corticosteroids (all P > 0.5). Mutational analysis of p53 could not explain the loss of Bax protein expression. Levels of Bcl-2 were not associated with sensitivity to any drug. In contrast to the ex vivo data, neither Bax or Bcl-2 expression nor doxorubicin sensitivity were associated with increased survival whereas sensitivity to fludarabine correlated with better overall survival (P = 0.031). These findings suggest that the resistance to purine nucleoside analogs and corticosteroids in B-CLL is due to inactivation of pathways different from those activated by anthracyclines, vinca alkaloids and alkylating agents and may be the molecular rationale for the efficacy of purine analogs in this disease.
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PMID:Bax expression correlates with cellular drug sensitivity to doxorubicin, cyclophosphamide and chlorambucil but not fludarabine, cladribine or corticosteroids in B cell chronic lymphocytic leukemia. 1204 Apr 35


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