Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic myeloid leukemia (CML) is characterized by the presence of a 210-kD protein (P210bcr-abl) in the cytoplasm of leukemic cells, generated by the reciprocal translocation between chromosome 9 and chromosome 22. Due to this translocation, the abl oncogene is coupled to the bcr gene, forming a new determinant in this protein encoded by the bcr-abl joining region. In the joining region itself, either the bcr exon 2 is coupled to the abl exon 2 (b2-a2), or the bcr exon 3 is coupled to the abl exon 2 (b3-a2). Thus, these joining regions form by definition new tumor-specific determinants in the respective chimeric P210-bcr-abl molecules. This paper addresses the question as to whether these tumor-specific joining regions are exposed on the P210bcr-abl molecule in such a way that antibodies can be generated to detect these sites. To test this possibility a polyclonal antiserum, termed BP-1, was raised against a synthetic peptide representative for the b2-a2 joining region. The reactivity of BP-1 was analyzed in an ELISA system on various synthetic peptides. Peptide inhibition studies showed the presence of antibodies to different parts of the b2-a2 peptide in the polyvalent antiserum. The reactivity of BP-1 was then tested with native P210bcr-abl molecules in various CML cell lines (K562, LAMA-84, and BV173) using a protein kinase assay. In this context, the bcr-abl junctions were first analyzed at the DNA and RNA level. The present study indicates that BP-1 specifically recognizes the b2-a2 junction in native P210bcr-abl. Furthermore, BP-1 clearly discriminates between b2-a2 P210bcr-abl and b3-a2 P210bcr-abl. We conclude that the tumor-specific b2-a2 joining region is antigenically exposed on the native P210bcr-abl molecule.
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PMID:Antibody recognition of the tumor-specific bcr-abl joining region in chronic myeloid leukemia. 246 13

A cell line (LAMA-84) has been established from the blood of a patient with chronic myeloid leukemia in acute phase. LAMA-84 cells retained the patient's chromosome abnormalities, i.e., triplication of all chromosomes except chromosome 18, the presence of Philadelphia (Ph) chromosome in 4-5 copies, and the presence of chromosome markers. LAMA-84 cells have morphological features of undifferentiated blast cells, but analyses have indicated that they belong to the megakaryocytic lineage; platelet peroxidase (PPO) was found in 8.5% of cells; LAMA-84 cells reacted spontaneously with poly- and monoclonal antibodies against the platelet glycoproteins (GP) IIb, IIIa, and the GPIIb/IIIa complex, whose presence was confirmed by crossed immunoelectrophoresis. LAMA-84 cells lack the membrane characteristics of lymphoid and mature granulocytic cells but do, however, react with certain antibodies to immature myeloid cells. Furthermore, they are positive with an antiglycophorin antibody, and contain alpha- and gamma-globin mRNA, thus demonstrating erythroid marker expression. Thus LAMA-84 is a tripotent, megakaryocytic, erythroid, and granulocytic cell line. The megakaryocytic and erythroid markers were enhanced by the addition of DMSO, butyrate, TPA, and hemin. The LAMA-84 cell line represents an interesting tool for the study of megakaryocytic and erythroid differentiation and the mechanisms of neoplastic growth.
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PMID:Human chronic myeloid leukemic cell line with positive Philadelphia chromosome exhibits megakaryocytic and erythroid characteristics. 347 10

The bcr-abl oncogene is a fusion gene resulting from a reciprocal translocation which forms the hallmark of chronic myeloid leukemia (CML). Antisense oligonucleotides complementary to the two possible mRNA breakpoints were found to inhibit cell growth of CML patient cells and cell lines, but doubt exists about their specificity. In order to test the specificity, phosphorothioate and 3' phosphorothioate capped antisense BCR-ABL oligonucleotides of different length were used. Stability, cellular uptake of oligonucleotides and effect on cell growth were studied in two CML cell lines, BV173 and LAMA-84. Phosphorothioate antisense BCR-ABL oligonucleotides were most stable, showed the highest uptake and induced cell death in BV173 but not in LAMA-84 cells. We selected the most effective antisense oligonucleotide for further analysis. The BV173 and LAMA-84 cell lines do not express the normal c-abl protein, we therefore used a c-abl specific monoclonal antibody for the detection of p210bcr-abl expression by flow cytometry. Dead cells found after treatment were gated out of analysis. Although BCR-ABL antisense oligonucleotides can induce apoptosis, no reduction of p210bcr-abl levels could be detected in living cells after treatment with antisense oligonucleotides. We conclude that antisense mediated inhibition of translation of mRNA into p210bcr-abl is not the mechanism responsible for the induction of apoptosis in cell line BV173.
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PMID:Phosphorothioate BCR-ABL antisense oligonucleotides induce cell death, but fail to reduce cellular bcr-abl protein levels. 784 6

We have compared the antileukaemic efficacy of a series of new i.v. injectable alkylphosphocholines (APC) with their clinically used congeners miltefosine and perifosine. The test system consisted of four leukaemic cell lines carrying the bcr-abl rearrangement (K-562, LAMA-84, CML-T1 and BV-173) and two other leukaemic cell lines (HL-60 and SKW-3) without this genetic alteration. The prototype of i.v. injectable APC, erucylphosphocholine, was more active against BCR-ABL-positive cell lines than the two reference APC. It induced programmed cell death in HL-60 and SKW-3 cells after exposure for 24 h, and in bcr-abl expressing cells after a prolonged incubation period (48 h). LAMA-84 cells responded to i.v. injectable APC with increased conversion to an adherent, fibroblast-like phenotype. Experiments with a cell-free system showed that the target structures of APC are localized within the cytoplasmic compartment. Blockade of ceramide synthase by fumonisin B1 was insufficient to prevent oligonucleosomal DNA fragmentation. Using RT-PCR we confirmed that K-562 and LAMA-84 cells carry the b3a2 fusion type, and CML-T1 and BV-173 the b2a2 variant. BV-173 cells had the lowest level of bcr-abl mRNA which correlated with their increased sensitivity. Transfection of K-562 cells with antisense oligonucleotides directed against bcr-abl caused a specific suppression of K-562 clonogenicity. Our data indicated that i.v. injectable alkylphosphocholines are potent inducers of apoptosis and display increased antileukaemic efficacy against BCR-ABL-positive blasts as compared with miltefosine and perifosine. The expression of BCR-ABL cannot prevent apoptosis but delays erucylphosphocholine-induced programmed cell death. Transfection with bcr-abl directed antisense oligonucleotides reduces the clonogenicity of K-562 cells.
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PMID:BCR-ABL influences the antileukaemic efficacy of alkylphosphocholines. 1058 26

A procedure for in-cell amplification of the hybrid BCR-ABL mRNA by reverse transcription and polymerase chain reaction (RT-PCR) without extraction of the nucleic acids was performed directly in fixed and permeabilized cells of leukemia patients (22 patients with Ph'-positive chronic myeloid leukaemia-CML and 1 with Ph'-positive acute leukaemia-AL, as well as 7 Ph'-negative cases) and Ph'-positive human leukaemia cell lines (K562, LAMA-84, BV173). The labelling of the amplified sequences was done employing biotinylated primers and a second PCR in a semi-nested fashion with a low number of cycles. An enzymatic system based on biotin-streptavidin-chromogen reaction was used for the detection of labeled PCR product, thus producing a coloured product, visible to the eye under a standard light microscope. All samples from patients with cytogenetic and molecular evidence of BCR-ABL rearrangement showed specific cytoplasmic staining at the site of the amplified hybrid transcripts. It allowed definite distinction between positive and negative cells. K562, LAMA-84, BV173 cells were characterized with strong diffuse staining while an interesting finding of the present study was the presence of variable quantities of colour product in patients' samples which might be due to different mRNA expression. Early and intermediate stages of myeloid maturation showed more intense reactivity. Cases with an aggressive course of accelerated or blast phase CML and AL were found to have a considerable subset of cells with strongly expressed signal while cases in chronic phase were characterised with uniform weak to moderate reaction. Our observations support the hypothesis that the amount of BCR-ABL transcript expression within neoplastic cells may play a role in dictating the eventual behaviour of the leukaemic clone. Future studies at a single cell level of larger series of consecutive cases with a follow up might be able to identify those patients who are prone to transformation and provide certain indications for further therapeutic decisions.
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PMID:Light microscopic detection of BCR-ABL transcripts after in-cell RT-PCR: fusion gene expression might correlate with clinical evolution of chronic myeloid leukemia. 1067 11

A crucial function of the BCR-ABL chimeric gene in chronic myeloid leukemia is the prolongation of cell survival by inhibition of apoptosis. BCR-ABL expression confers cross-resistance to multiple genotoxic anticancer drugs by inhibition of the apoptotic response to DNA damage in association with cell cycle arrest at the G2-M restriction point. Previous reports indicated that BCR-ABL exerts its antiapoptotic effect against various apoptotic stimuli upstream to the cleavage and activity of caspase-3. Here we show that the adenovirus E1A protein induces substantial apoptosis in BCR-ABL expressing K562 and LAMA-84 leukemia cells. This apoptotic activity of E1A is accompanied by processing of caspase-3 and cleavage of poly(ADP-ribose) polymerase and can be significantly blocked by z-VAD-fmk Z-Val-Ala-Asp(OCH3)-CH2F and the caspase-3-specific inhibitor Z-DEVD-FMK Z-Asp(OCH3)-Glu-Val-Asp(OCH3)-CH2F. Moreover, E1A renders K562 cells, which are particularly resistant to cell death irrespective of the inducing agent, susceptible to induction of apoptosis by the chemotherapeutic agents etoposide and daunorubicin. Counteracting the DNA damage-induced inactivation of cdc2 kinase, E1A reverses the drug-induced G2-M arrest These results indicate that solitary delivery of E1A significantly antagonizes BCR-ABL-induced antiapoptotic functions and circumvents the inherent resistance to DNA damage-induced apoptosis, supporting the use of E1A in combination with chemotherapeutic agents as a promising therapeutic strategy for successful treatment of Philadelphia chromosome-positive leukemia in vivo.
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PMID:E1A overcomes the apoptosis block in BCR-ABL+ leukemia cells and renders cells susceptible to induction of apoptosis by chemotherapeutic agents. 1091 74

Expression of the transforming oncogene bcr-abl in chronic myelogenous leukemia (CML) cells is reported to confer resistance against apoptosis induced by many chemotherapeutic agents such as etoposide, ara-C, and staurosporine. In the present study some members of a series of novel pyrrolo-1,5-benzoxazepines potently induce apoptosis, as shown by cell shrinkage, chromatin condensation, DNA fragmentation, and poly(ADP-ribose) polymerase (PARP) cleavage, in three CML cell lines, K562, KYO.1, and LAMA 84. Induction of apoptosis by a representative member of this series, PBOX-6, was not accompanied by either the down-regulation of Bcr-Abl or by the attenuation of its protein tyrosine kinase activity up to 24 h after treatment, when approximately 50% of the cells had undergone apoptosis. These results suggest that down-regulation of Bcr-Abl is not part of the upstream apoptotic death program activated by PBOX-6. By characterizing the mechanism in which this novel agent executes apoptosis, this study has revealed that PBOX-6 caused activation of caspase 3-like proteases in only two of the three CML cell lines. In addition, inhibition of caspase 3-like protease activity using the inhibitor z-DEVD-fmk blocked caspase 3-like protease activity but did not prevent the induction of apoptosis, suggesting that caspase 3-like proteases are not essential in the mechanism by which PBOX-6 induces apoptosis in CML cells. In conclusion, this study demonstrates that PBOX-6 can bypass Bcr-Abl-mediated suppression of apoptosis, suggesting an important potential use of these compounds in the treatment of CML.
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PMID:Pyrrolo-1,5-benzoxazepines induce apoptosis in chronic myelogenous leukemia (CML) cells by bypassing the apoptotic suppressor bcr-abl. 1112 59

Here we demonstrate that treatment with SAHA (suberoylanilide hydroxamic acid), a known inhibitor of histone deacetylases (HDACs), alone induced p21 and/or p27 expressions but decreased the mRNA and protein levels of Bcr-Abl, which was associated with apoptosis of Bcr-Abl-expressing K562 and LAMA-84 cells. Cotreatment with SAHA and imatinib (Gleevec) caused more down-regulation of the levels and auto-tyrosine phosphorylation of Bcr-Abl and apoptosis of these cell types, as compared with treatment with either agent alone (P <.05). This finding was also associated with a greater decline in the levels of phospho-AKT and Bcl-x(L). Significantly, treatment with SAHA also down-regulated Bcr-Abl levels and induced apoptosis of CD34(+) leukemia blast progenitor cells derived from patients who had developed progressive blast crisis (BC) of chronic myelocytic leukemia (CML) while receiving therapy with imatinib. Taken together, these findings indicate that cotreatment with SAHA enhances the cytotoxic effects of imatinib and may have activity against imatinib-refractory CML-BC.
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PMID:Cotreatment with the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) enhances imatinib-induced apoptosis of Bcr-Abl-positive human acute leukemia cells. 1244 42

The aim of this study was to enhance the antileukemic efficacy of the alkylphosphocholine erucylphospho-N,N,N-trimethylpropylammonium (ErPC3) in chronic myeloid leukemia (CML)-derived cell lines by a bcr-directed antisense oligonucleotide (ASO-bcr). The mechanism was substantiated by Western blotting of the BCR-ABL expression level of CML cells, and the efficacy was substantiated by inhibition of colony formation compared with normal hematopoietic cells. The clonogenicity of K-562 cells expressing high levels of p210(BCR-ABL) was inhibited significantly by the ASO-bcr (T/C%, 30; P < 0.05) but not by ErPC3 (T/C%, 70). Combined sequential exposure to ErPC3 and the ASO-bcr, however, inhibited synergistically colony growth (T/C%, 3; P < 0.01). The colony growth of BV-173 cells expressing lower levels of p210(BCR-ABL) than K562 cells was inhibited to a greater extent by the ASO-bcr (T/C%, 15; P < 0.01). AR-230 cells that express high levels of p230(BCR-ABL) showed an intermediate decrease in colony formation in response to the ASO-bcr (T/C%, 20; P < 0.05). BCR-ABL levels of BV-173, CML-T1, and LAMA-84 cells were reduced in response to the ASO-bcr, as evidenced by Western blot. However, K-562 and AR-230 cells showed reduced BCR-ABL expression only after repeated treatment. ErPC3 and the ASO-bcr did not reduce colony formation (CFU-GM) of normal mouse bone marrow cells from long-term bone marrow cell cultures; instead, ErPC3 stimulated colony formation (P < 0.05) and did not induce chromosomal aberrations in mouse bone marrow. In conclusion, the combination of ErPC3 with a suitable antisense oligonucleotide inhibited synergistically colony formation of CML cell lines without damaging normal cells and thus might have a bearing on the purging of autologous hematopoietic transplants in CML patients.
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PMID:Combination with an antisense oligonucleotide synergistically improves the antileukemic efficacy of erucylphospho-N,N,N-trimethylpropylammonium in chronic myeloid leukemia cell lines. 1249 21

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


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