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)

The components of the apoptotic program are targets for anticancer therapy. Bcl-2 protein inhibits apoptosis and confers resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy, and monoclonal antibodies (mAb). Oblimersen sodium (G3139, Genasense, Genta Inc., Berkeley Heights, NJ) is an antisense oligonucleotide (AS-ON) compound designed to specifically bind to the first 6 codons of the human bcl-2 mRNA sequence, resulting in degradation of bcl-2 mRNA and subsequent decrease in Bcl-2 protein translation. Oblimersen is the first oligonucleotide to demonstrate proof of principle of an antisense effect in human tumors by the documented downregulation of the target Bcl-2 protein. A growing body of preclinical and clinical evidence suggests that oblimersen synergizes with many cytotoxic and biologic/immunotherapeutic agents against a variety of hematologic malignancies and solid tumors. Randomized clinical trials are currently underway to evaluate the efficacy and tolerability of oblimersen in combination with cytotoxic chemotherapy in chronic lymphocytic leukemia, multiple myeloma, malignant melanoma, and non-small cell lung cancer. In addition, nonrandomized trials are under way to evaluate oblimersen in non-Hodgkin's lymphoma, acute myeloid leukemia, and hormone-refractory prostate cancer. Preclinical data also support the clinical evaluation of oblimersen in additional tumor types, including chronic myelogenous leukemia and breast, small cell lung, gastric, colon, bladder, and Merkel cell cancers. Enhancement of the efficacy of anticancer treatments with oblimersen Bcl-2 antisense therapy represents a promising new apoptosis-modulating strategy, and ongoing clinical trials will test this therapeutic approach.
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PMID:Oblimersen Bcl-2 antisense: facilitating apoptosis in anticancer treatment. 1216 2

Bcr-Abl is a constitutively active tyrosine kinase involved in the development and progression of chronic myeloid leukaemia (CML). It has been demonstrated that Bcr-Abl-positive cells can be uniquely resistant to apoptosis induced by different types of stimuli, but the mechanism by which this is achieved is not defined. In this study we have investigated how cells expressing high expression levels of Bcr-Abl may gain resistance to cytotoxic drugs. We have established cell lines expressing low and high expression levels of Bcr-Abl. Cells expressing elevated Bcr-Abl are resistant to cytotoxic drugs. In drug-sensitive 32D-parental and low Bcr-Abl expressing cells, pro-apoptotic Bcl-2 family members, Bax and Bad translocate from the cytosol to the mitochondrion following a cytotoxic insult. In contrast, high Bcr-Abl expression prevents the early translocation of these pro-apoptotic proteins to the mitochondrion, mitochondrial membrane potential is retained and caspases are inactive. We also demonstrate that IL-3 can contribute to drug resistance in low Bcr-Abl expressing cells, however, independent inhibition of IL-3 activated pathways (PI3K/AKT and Jak/STAT) does not sensitise cells to apoptosis. This study demonstrates that the subcellular translocation of Bax and Bad can be regulated by elevated Bcr-Abl expression and this may be a key event in the abrogation of an apoptotic response following a cytotoxic insult.
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PMID:High Bcr-Abl expression prevents the translocation of Bax and Bad to the mitochondrion. 1220 Jun 87

To explore Bcl-2 and P53 gene proteins expression on human leukemia cells and their relationship with chemotherapeutic efficacy, Bcl-2 and P53 gene proteins expression was assayed by ABC immunohistochemical staining. Results showed that the expression rates of Bcl-2 and P53 gene proteins were 67% and 41% respectively in leukemia cells from 52 patients. While there was no difference of Bcl-2 protein level in ALL and ANLL, the P53 protein level was higher in ANLL than that in ALL (P < 0.05). When CML patients got into the blast crisis phase, the level of Bcl-2 and P53 proteins became very high. Compare with previously untreated AL, relapse/refractory AL patients had higher Bcl-2 and P53 protein level, lower marrow complete remission, and was easy to relapse. The expression of Bcl-2 and P53 protein could be used as new predictors of chemotherapeutic efficacy and prognosis in patients with leukemia. The high protein expression of Bcl-2 and P53 demonstrated that CML was conversion to blast crisis phase.
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PMID:[Expression of Bcl-2 and P53 Gene Proteins on Leukemia Cells and Its Correlation with Chemotherapeutic Efficacy] 1257 96

The mechanism of action of farnesyltransferase inhibitors (FTIs) has not been fully clarified. We investigated the cytotoxic effects of various FTIs in chronic myeloid leukemia (CML), using LAMA cells and marrow cells from 40 CML patients in chronic phase. FTI-mediated cytotoxic effect was observed in LAMA cells and in 65% of primary CML cells, whereas marrow cells from controls were only weakly affected. Cytotoxic effects were partially related to enhanced apoptosis; however, Fas-receptor (FasR) and Fas-ligand (FasL) expression were not modified by FTIs. Susceptibility to FTI-mediated inhibition did not correlate with FasR/FasL expression in CD34+ CML cells. Moreover, intra-cellular activation of caspase-1 and -8 were not altered by FTIs, and their blockade did not reverse FTI toxicity. However, we observed FTI-induced activation of caspase-3, and its inhibition partially reverted FTI-induced apoptosis. FTIs did not modulate bcl2, bclxL, and bclxS expression, whereas they increased inducible nitric oxide (iNOS) mRNA and protein levels, resulting in higher NO production. Furthermore, C3 exoenzyme, a Rho inhibitor, significantly increased iNOS expression in CML cells, suggesting that FTIs may up-regulate NO formation at least partially through FTI-mediated inhibition of Rho. We conclude that FTIs induce selective apoptosis in CML cells via activation of iNOS and caspase-3.
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PMID:Involvement of nitric oxide in farnesyltransferase inhibitor-mediated apoptosis in chronic myeloid leukemia cells. 1271 96

The components of the apoptotic pathway are targets for anticancer therapy. Bcl-2 protein inhibits apoptosis and confers resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy, and monoclonal antibodies. Oblimersen sodium (G3139, Genasense, Genta Inc, Berkeley Heights, NJ) is an antisense oligonucleotide compound designed to specifically bind to the first six codons of the human bcl-2 mRNA sequence, resulting in degradation of bcl-2 mRNA and subsequent decrease in Bcl-2 protein translation. Oblimersen is the first oligonucleotide to demonstrate proof of principle of an antisense effect in human tumors by the documented downregulation of the target Bcl-2 protein. A growing body of preclinical and clinical evidence suggests that oblimersen synergizes with many cytotoxic and biologic/immunotherapeutic agents against a variety of hematologic malignancies and solid tumors. Randomized clinical trials are currently underway to evaluate the efficacy and tolerability of oblimersen in combination with cytotoxic chemotherapy in chronic lymphocytic leukemia (CLL), multiple myeloma (MM), malignant melanoma, and non-small cell lung cancer. In addition, nonrandomized trials are underway to evaluate oblimersen in non-Hodgkin's lymphoma (NHL), acute myeloid leukemia (AML), and hormone-refractory prostate cancer. Preclinical data support the clinical evaluation of oblimersen in additional tumor types, including chronic myelogenous leukemia, and breast, small cell lung, gastric, colon, bladder (CML), and Merkel cell cancers. Enhancement of the efficacy of anticancer treatments with oblimersen Bcl-2 antisense therapy represents a promising new apoptosis-modulating strategy, and ongoing clinical trials will test this therapeutic approach.
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PMID:Oblimersen sodium (G3139 Bcl-2 antisense oligonucleotide) therapy in Waldenstrom's macroglobulinemia: a targeted approach to enhance apoptosis. 1272 Jan 57

Cytokine-provided survival signals are known to suppress apoptosis through inhibition of mitochondrial pathways that involve Bcl-2 family members. Here we show that in hematopoietic cells, cytokines also regulate death receptor-mediated pathways. We demonstrate that hematopoietic cytokines such as IL-3 and erythropoietin in normal cells, as well as BCR-ABL oncoprotein in transformed cells, inhibit transcription of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Using small interfering RNAs, we show that the inhibition of TRAIL function is sufficient to partially rescue cytokine-deprived cells from apoptosis. Finally, we demonstrate that cytokine and BCR-ABL suppression of TRAIL transcription is mediated through phosphorylation and inhibition of the forkhead FOXO3a transcription factor. BCR-ABL-induced inhibition of TRAIL transcription in hematopoietic cells may provide a novel mechanism for tumorigenicity in chronic myeloid leukemia.
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PMID:Cytokines and BCR-ABL mediate suppression of TRAIL-induced apoptosis through inhibition of forkhead FOXO3a transcription factor. 1275 Apr 77

The endoplasmic reticulum (ER) is the site where proteins destined to either secretion or different subcellular compartments assemble and the major storage of intracellular Ca(2+). The ER stress resulting from a variety of toxic insults leads to apoptosis. Here, we showed that the apoptotic death triggered by STI571, an inhibitor of the p210 bcr-abl tyrosine kinase, in murine myeloid progenitors transducing the p210 bcr-abl tyrosine kinase of Chronic Myeloid Leukemia (CML) proceeds from ER stress. The Bcl-2 dowmodulation and inactivation induced by the binding to its antagonist: Bad, the release of caspase 12 from the ER membranes in its active form and of Ca(2+) from the ER pool addressed towards ER a sensor of STI571-induced pro-apoptotic signal.
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PMID:Endoplasmic reticulum stress initiates apoptotic death induced by STI571 inhibition of p210 bcr-abl tyrosine kinase. 1465 84

The regulation of apoptosis is an important potential target for anticancer therapy. The mitochondrial Bcl-2 protein inhibits apoptosis and is therefore an important mediator of resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy and monoclonal antibody therapy. Oblimersen (Genasense, Aventis Pharmaceuticals / Genta Inc) is a 18mer antisense-oligonucleotide (ASO), which specifically binds to the first 6 codons of the human bcl-2 mRNA, resulting in degradation and destruction of the mRNA by RNAse H. Subsequently there is a significant decrease of bcl-2 translation. A growing number of preclinical and clinical studies suggests that the combination of cytotoxic therapy with Oblimersen results in synergistic anticancer efficacy in many hematologic and solid tumors. Due to its low toxicity profile, oblimersen is an ideal combination partner with conventional chemotherapy. Three randomized phase-III trials (malignant melanoma, chronic lymphocytic leukemia, multiple myeloma) have recently finished recruitment. The results of these studies will be available by the end of 2003. Based on preclinical data, a lot of nonrandomized phase-II studies on several different tumor types like AML, CML, NHL, prostate cancer and breast cancer are underway. The manipulation of proapoptotic and antiapoptotic factors in favor of proapoptotic factors by inhibition of the bcl-2 protein translation in order to enhance the efficacy of anticancer treatments represents a promising new treatment concept in oncology.
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PMID:[Proapoptotic therapy with oblimersen (bcl-2 antisense oligonucleotide)--review of preclinical and clinical results]. 1471 45

Tannins are a group of widely distributed plant polyphenols, some of which are beneficial to health because of their chemopreventive activities. In the present study, we investigated the effects and action mechanisms of woodfordin I, a macrocyclic ellagitannin dimer, on human chronic myelogenous leukemia (CML) K562 cells. The results showed that woodfordin I was able to suppress the proliferation and induce apoptosis in K562 cells. Apoptosis was evaluated by cytomorphology, internucleosomal DNA fragmentation, and externalization of phosphatidylserine. Woodfordin I treatment caused a rapid and sustained loss of mitochondrial transmembrane potential (MMP), transient generation of reactive oxygen species (ROS), transient elevation of intracellular Ca2+ concentration, and cytosolic accumulation of cytochrome c. The activation of caspase-9 and 3, but not caspase-8, was also demonstrated, indicating that the apoptotic signaling triggered by woodfordin I was mediated through the intrinsic mitochondria-dependent pathway. Western blot and immunofluorescence analysis revealed that the anti-apoptotic Bcl-2 and Bcl-xL levels were downregulated, together with the pro-apoptotic Bax protein. Significantly, woodfordin I-induced apoptosis was associated with a decline in the levels of c-Abl, Bcr-Abl, and cellular protein tyrosine phosphorylation. Considering the consequence of all the events in the process of woodfordin I-induced apoptosis, the mitochondrial dysfunction is directly responsible for the pro-apoptotic effects on K562 cells. Furthermore, because CML is a malignancy of pleuripotent hematopoietic cells caused by the dysregulated tyrosine kinase activity of Bcr-Abl, these findings suggest that woodfordin I may be a potential lead compound against CML.
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PMID:Mitochondrial dysfunction as an early event in the process of apoptosis induced by woodfordin I in human leukemia K562 cells. 1473 95

Allogeneic bone marrow transplantation (alloBMT) is the only curative therapy for chronic myelogenous leukemia (CML). This success is explained by the delivery of high doses of antineoplastic agents followed by the rescue of marrow function and the induction of graft-versus-leukemia reaction mediated by allogeneic lymphocytes against host tumor cells. This reaction can also be induced by donor lymphocyte infusion (DLI) producing remission in most patients with CML who relapse after alloBMT. The immunological mechanisms involved in DLI therapy are poorly understood. We studied five CML patients in the chronic phase, who received DLI after relapsing from an HLA-identical BMT. Using flow cytometry we evaluated cellular activation and apoptosis, NK cytotoxicity, lymphocytes producing cytokines (IL-2, IL-4 and IFN-gamma), and unstimulated (in vivo) lymphocyte proliferation. In three CML patients who achieved hematological and/or cytogenetic remission after DLI we observed an increase of the percent of activation markers on T and NK cells (CD3/DR, CD3/CD25 and CD56/DR), of lymphocytes producing IL-2 and IFN-gamma, of NK activity, and of in vivo lymphocyte proliferation. These changes were not observed consistently in two of the five patients who did not achieve complete remission with DLI. The percent of apoptotic markers (Fas, FasL and Bcl-2) on lymphocytes and CD34-positive cells did not change after DLI throughout the different study periods. Taken together, these preliminary results suggest that the therapeutic effect of DLI in the chronic phase of CML is mediated by classic cytotoxic and proliferative events involving T and NK cells but not by the Fas pathway of apoptosis.
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PMID:Immunological effects of donor lymphocyte infusion in patients with chronic myelogenous leukemia relapsing after bone marrow transplantation. 1476 74


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