Posted by rob on April 27, 2006 under Uncategorized | 
We evaluated the effect of the human immunodeficiency virus (HIV) protease inhibitor saquinavir on the imatinib-sensitive and imatinib-resistant chronic myelogenous leukemia cell lines. Saquinavir, which is also a proteasome blocker, showed dose- and time-related anti-proliferative activity, particularly on the imatinib-resistant lines and a pro-apoptotic effect. Association with imatinib caused a significant increase of activity.
The effects of saquinavir on imatinib-resistant chronic myelogenous leukemia cell lines.
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Boissel N,
Rea D,
Tieng V,
Dulphy N,
Brun M,
Cayuela JM,
Rousselot P,
Tamouza R,
Le Bouteiller P,
Mahon FX,
Steinle A,
Charron D,
Dombret H,
Toubert A
MHC class I chain-related molecules (MIC) participate in immune surveillance of cancer through engagement of the NKG2D-activating receptor on NK and T cells. Decreased NKG2D expression and function upon chronic exposure to NKG2D ligands and/or soluble forms of MIC (sMIC) may participate in immune escape. In chronic myeloid leukemia, a malignancy caused by the BCR/ABL fusion oncoprotein, we showed cell surface expression of MICA on leukemic, but not healthy, donor hemopoietic CD34+ cells. At diagnosis, chronic myeloid leukemia patients had abnormally high serum levels of sMICA and weak NKG2D expression on NK and CD8+ T cells, which were restored by imatinib mesylate (IM) therapy. In the BCR/ABL+ cell line K562, IM decreased both surface MICA/B expression and NKG2D-mediated lysis by NK cells. Silencing BCR/ABL gene expression directly evidenced its role in the control of MICA expression. IM did not affect MICA mRNA levels, but decreased MICA protein production and release. Sucrose density gradient fractionation of K562 cytoplasmic extracts treated with IM showed a shift in the distribution of MICA mRNA from the polysomal toward the monosomal fractions, consistent with decreased translation. Among the major pathways activated by BCR/ABL that regulate translation, PI3K and mammalian target of rapamycin were shown to control MICA expression. These data provide evidence for direct control of MICA expression by an oncogene in human malignancy and indicate that posttranscriptional mechanisms may participate in the regulation of MICA expression.
BCR/ABL oncogene directly controls MHC class I chain-related molecule A expression in chronic myelogenous leukemia.
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Molecular monitoring of the BCR-ABL transcript in chronic myelogenous leukemia (CML) using quantitative RT-PCR provides clinicians with important diagnostic and prognostic information. To determine whether molecular detection and monitoring of CML is comparable using peripheral blood (PB) and bone marrow (BM) aspirate samples, we performed a prospective study using quantitative real-time RT-PCR (QRT-PCR) of paired PB and BM samples from 41 patients with CML entered onto a single Cancer and Leukemia Group B (CALGB) treatment study. QRT-PCR analysis of PB and BM samples was performed prior to initiation of, and during, treatment with homoharringtonine and cytarabine on a CALGB study for previously untreated CML. Statistical analyses demonstrated good agreement of PB and BM pre-treatment samples. However, using the Bland-Altman statistical method that measures true agreement between PB and BM values, we found that there was only modest agreement of BCR-ABL measurements in PB and BM for samples obtained during treatment. PB values obtained during treatment tended to be lower than the corresponding BM values [average difference = -0.37 (p
Quantitative real-time RT-PCR monitoring of BCR-ABL in chronic myelogenous leukemia shows lack of agreement in blood and bone marrow samples.
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This report describes a chronic myelogenous leukaemia patient with an apparently normal bone marrow karyotype but BCR/ABL fusion-gene-positive. Commercial FISH probes showed an atypical pattern and the BCR/ABL fusion transcript was detected by RT-PCR, but not the reciprocal ABL/BCR. Consecutive FISH assays clarified the mechanism of the masked Ph. The ABL gene and the following 5.6-5.7 Mb of 9q are inserted into the BCR region of chromosome 22. There is no transference of 22q material to chromosome 9 or to any other chromosomes. Clinical features and evolution of the patient are similar to those cases with classic Ph chromosome. Copyright (c) 2006 John Wiley & Sons, Ltd.
Generation of the BCR/ABL fusion gene in a Philadelphia chromosome-negative chronic myeloid leukaemia: insertion of 5.6 Mb of 9q34 into the BCR region of chromosome 22.
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A 50-year-old male was diagnosed with chronic myelogenous leukaemia (CML) in chronic phase in March 2000. He was treated initially with hydroxyurea, administered orally. This was changed to interferon alpha (IFN) 5 million units (5 MIU) subcutaneously daily in May 2000; complete cytogenetic response was achieved 11 months later. IFN dosage was reduced to 5 MIU, alternate days, in June 2001 and a cytogenetic relapse occurred 3 months later. Since April 2002, he has received IFN 5 MIU three times weekly in combination with imatinib 200 mg/day. The Philadelphia chromosome disappeared from his peripheral blood cells in July 2002 and a complete molecular response was achieved in January 2003. Serial molecular studies between January 2004 and January 2005 showed no detectable major BCR/ABL chimeric transcript. Grade 2 neutropenia and grade 1 non-haematological adverse effects have been observed. This case report suggests the combination of low-dose imatinib and IFN would be tolerable and effective for CML patients in chronic phase.
Durable molecular complete remission induced by low-dose imatinib plus low-dose interferon alpha in a patient with chronic myelogenous leukaemia.
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Chronic myelogenous leukemia (CML), also known as chronic myelocytic or chronic myeloid leukemia, is a clonal disorder of hematopoiesis that arises in a hematopoietic stem cell or early progenitor cell. This is characterized by the dysregulated production of mature nonlymphoid cells with normal differentiation. Eventually, in spite of the term chronic, there is progression to acute leukemia, usually of the myeloid variety, which is highly resistant to current therapies. Despite recent improvements in the treatment of early-stage disease, CML blast crisis (CMLBC) remains a therapeutic challenge. CMLBC is highly refractory to standard induction chemotherapy, with a response rate in myeloid blast crisis of less than 30%. Conventional chemotherapy has been much less successful in this disease compared with de novo acute leukemia, with a mean survival after diagnosis of blast crisis of only 2 to 4 months for nonresponders. Many regimens of chemotherapies have been tried in CMLBC, with minor success. Although imatinib was evaluated in patients with CMLBC, most CMLBC cases today arise in patients already on imatinib-based therapy and developing blastic phase on that therapy; thus there is no standard therapy for patients with CMLBC. Further studies of the mechanisms of transformation of chronic-phase CMLBC at a molecular level, and methods to target these molecular abnormalities, will determine the future direction of new treatment modalities. The prognosis of CML in blast crisis remains disappointing, despite great efforts. Currently, the most successful strategy for improving survival in CML is by prolonging the chronic phase and delaying the onset of blast crisis.
Blastic phase of chronic myelogenous leukemia.
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To evaluate the prognostic significance of submicroscopic deletions of the ABL or BCR gene associated with t(9;22) in chronic myelogenous leukemia (CML), we investigated the incidence of an ABL or BCR deletion on derivative chromosome 9 using fluorescence in situ hybridization (FISH). FISH was performed using the LSI BCR/ABL dual-fusion translocation probe on bone marrow cells of 86 patients with CML. Of 86 patients, ABL deletion was detected in 13 (15.1%) patients and BCR deletion in 8 patients (9.3%). Patients with ABL deletion showed shorter event-free survival time (EFS) than those without ABL deletion (P = 0.020). Patients with BCR deletion showed significantly short overall survival time (OS; P = 0.039). Patients with ABL and/or BCR deletion (14/86 patients, 16.3%) showed significantly short OS and EFS (median OS, 43.0 months; median EFS, 40.0 months), compared to the patients without any BCR or ABL gene deletions (median OS, 94.0 months; median EFS, 90.0 months; P = 0.041 for OS, P = 0.008 for EFS). All the patients with BCR deletion, except for one, had a concomitant ABL deletion, suggesting that BCR deletion occurs in conjunction with ABL deletion. In patients with ABL deletion only, BCR/ABL rearrangement with b2a2 mRNA type tended to be more frequent than in patients without any deletion of the two genes (P = 0.073). Deletion of any of the BCR or ABL genes on derivative chromosome 9 was associated with both short OS and EFS. We conclude that deletion of not only the ABL gene, but also of the BCR gene, is a poor prognostic marker that indicates rapid disease progression in CML.
Deletion of any part of the BCR or ABL gene on the derivative chromosome 9 is a poor prognostic marker in chronic myelogenous leukemia.
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Imatinib mesylate is highly effective in relapsed chronic myelogenous leukemia (CML) after allogeneic hematopoetic stem cell transplantation (HSCT). However, it is unknown whether imatinib produces durable molecular remissions. The outcome of CML patients transplanted at our center who had received only imatinib for relapse after HSCT was compared with that of patients treated with donor lymphocyte infusions (DLI). Imatinib therapy resulted in a higher incidence of relapse and inferior leukemiafree survival (p=0.006 and p=0.016, respectively). These data suggest that imatinib alone probably does not cure relapse after HSCT.
A comparison of donor lymphocyte infusions or imatinib mesylate for patients with chronic myelogenous leukemia who have relapsed after allogeneic stem cell transplantation.
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In the multinational IRIS study comparing imatinib to interferon plus cytarabine (IFN/AraC) in patients with newly diagnosed chronic-phase chronic myelogenous leukaemia (CP CML), imatinib demonstrated significantly higher rates of complete cytogenetic responses (CCyR) and improved progression free survival (PFS). However, because of a high early cross over rate to imatinib, survival benefit was not assessable. Here we report the result of a study comparing long term outcome of patients included in two prospective randomized trials: 551 patients assigned to imatinib in the IRIS trial from 2000 to 2001 and 325 patients who received the combination IFN/AraC in the CML91 trial between 1991 and 1996 before imatinib was available. With a follow-up of 42 months for both groups of patients, estimated CCyR, survival free of transformation and overall survival were significantly higher with imatinib compared with IFN/AraC (P
Survival advantage from Imatinib compared to the combination Interferon-{alpha} plus Cytarabine in chronic phase CML: historical comparison between two phase III trials.
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Three of the most promising antigens for immunotherapy of chronic myelogenous leukaemia (CML) include the specific fusion-protein, Bcr/Abl, and the overexpressed proteins WT1 and Proteinase 3. The clinical significance of Proteinase 3 as a target in myelogenous leukaemias has been bolstered by detection of high frequencies of cytotoxic CD8+ lymphocytes specific for this antigen in patients undergoing immune therapies. Our investigation aimed to directly identify MHC-ligands derived from these antigens and presented on CML blasts by means of affinity-purification and mass spectrometric peptide-sequencing. Although no known or potential new epitopes were discovered for Bcr/Abl or WT1, a novel peptide from Proteinase 3 was detected among the more abundant MHC-ligands. Additionally, MHC-ligands derived from known immunogenic proteins overexpressed as a result of Bcr/Abl transformation were also identified. Our investigation is the second of only a small number of studies to identify a peptide from Proteinase 3 among the more abundant MHC-associated peptides and thus implies that peptides from this antigen are among the more abundantly presented of the known leukaemic antigens. Taken in conjunction with clinical observations of functional Proteinase 3 specific CTL in patients’, these data further support the application of this antigen as an immunotherapeutical target for myelogenous leukaemias.Leukemia advance online publication, 20 April 2006; doi:10.1038/sj.leu.2404234.
A novel MHC-associated Proteinase 3 peptide isolated from primary chronic myeloid leukaemia cells further supports the significance of this antigen for the immunotherapy of myeloid leukaemias.
