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  • American Society of Hematology  (238)
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  • 1
    In: Blood, American Society of Hematology, Vol. 117, No. 16 ( 2011-04-21), p. 4376-4386
    Abstract: Recruitment and adhesion of bone marrow (BM)–derived circulating progenitor cells to ischemic tissue are important for vasculogenesis and tissue repair. Recently, we found cartilage oligomeric matrix protein (COMP)–Ang1 is a useful cell-priming agent to improve the therapeutic efficacy of progenitor cells. However, the effect and the underlying mechanisms of COMP-Ang1 on recruitment of BM-derived progenitor cells (BMPCs) to foci of vascular injury have not been well defined. Here, we found that COMP-Ang1 is a critical stimulator of stromal cell–derived factor 1 (SDF-1), the principal regulator of BM-cell trafficking. Furthermore, SDF-1 stimulation by COMP-Ang1 was blocked by small-interfering RNA (siRNA) against hypoxia-inducible factor-1α (HIF-1α). COMP-Ang1 increased the synthesis of HIF-1α by activating mammalian target of rapamycin (mTOR) in hypoxic endothelium. The intermediate mechanism transmitting the COMP-Ang1 signal to the downstream mTOR/HIF-1α/SDF-1 pathway was the enhanced binding of the Tie2 receptor with integrin-linked kinase (ILK), an upstream activator of mTOR. In the mouse ischemic model, local injection of COMP-Ang1 stimulated the incorporation of BMPCs into ischemic limb, thereby enhancing neovasculogenesis and limb salvage. Collectively, our findings identify the COMP-Ang1/HIF-1α/SDF-1 pathway as a novel inducer of BMPC recruitment and neovasculogenesis in ischemic disease.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2011
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 116, No. 21 ( 2010-11-19), p. 5188-5188
    Abstract: Abstract 5188 Background: Reactive oxygen species (ROS) such as superoxide and H2O2 have roles signaling for molecules on angiogenesis. NADPH oxidase Nox2 (gp91phox) is a major source of ROS. Previous, we had found that Nox2-based NADPH oxidase (gp91phox)-induced ROS may play important roles on EPCs migration and proliferation by VEGF (Blood. 2009;114:Abstract 1445). In the present study, we studied the impact of down-regulation of Nox2 on intracellular ROS level, proliferation, transmigration, and in vitro tube formation of HCB derived EPCs via Nox2 siRNA transfection. Methods: Outgrowing endothelial progenitor cells were established from mononuclear cells of human cord blood (Yoo et al, Stem cells. 2003;21:228-235) using EGM-2 media in a fibronectin-coated dish. EPCs were transfected with HiPerFection transfection reagent plus Nox2 siRNA or non-targeting control siRNA and cultured for 5 hours. 100ng/ml of VEGF was added to the transfected cells and cultured for overnight. Expression of Nox2 and pERK in the Nox2 siRNA transfected EPCs were detected by western blot analysis. Intracellular ROS level was analyzed by staining with 2, 7-dichlrodihydro-fluorescein-diacetate (H2DCF-DA) and flow cytometry. Transmigration against VEGF was performed using transwell system (Costar) and in vitro tube formation was assayed using In vitro angiogenesis kit (Chemicon). Results: Intracellular ROS level was increased during endothelial progenitor cell culture which were derived from HCB by VEGF treatment. Proliferation, in vitro tube formation matrigel assay and migration assay on endothelial progenitor cells using VEGF were decreased with Nox2 siRNA transfection when compared with that of control group. In western blot data, Nox2-based NADPH oxidase (gp91phox) was increased by VEGF and decreased by Nox2 siRNA transfection. VEGF induced pERK expression was also decreased by Nox2 siRNA transfection as well. Conclusions: Based on our studies, Nox2-based NADPH oxidase (gp91phox)-induced ROS may have important roles on proliferation in HCB induced EPCs by VEGF stimulation. Furthermore, Nox2 siRNA transfection into HCB derived EPC down-regulated intracellular ROS production and pERK expression. Our data may be useful finding the new therapeutic targets for ischemic heart and ischemic limb diseases by manipulating the level of intracellular ROS via Nox2. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2010
    detail.hit.zdb_id: 1468538-3
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  • 3
    In: Blood, American Society of Hematology, Vol. 126, No. 6 ( 2015-08-06), p. 746-756
    Abstract: Nilotinib plus multiagent chemotherapy was feasible and showed a comparable outcome to previous results with imatinib for Ph-pos ALL. The achievement of deep MR with nilotinib at postremission correlated well with the clinical outcomes for Ph-pos ALL.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2015
    detail.hit.zdb_id: 1468538-3
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  • 4
    In: Blood, American Society of Hematology, Vol. 122, No. 21 ( 2013-11-15), p. 55-55
    Abstract: We previously reported the interim analysis on the clinical outcome of nilotinib (Tasigna®, Novartis Pharma, Basel, Switzerland), when combined with multi-agent chemotherapy for newly diagnosed Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL) in adults. Herein, we reported the final results of the multicenter prospective phase2 trial of Adult Acute Lymphoblastic Leukemia Working Party, the Korean Society of Hematology. Newly diagnosed Ph+ALL patients aged 18 years old or more were eligible when they had adequate organ function. Diagnosis of Ph+ALL was performed via confirmation of the presence of Ph chromosome by conventional GTL-band technique, and/or positive molecular analysis with nested RT PCR for detection of BCR-ABL fusion transcripts. Written informed consent was obtained from all subjects. All patients received induction treatment consisting of vincristine, daunorubicin, oral or parenteral prednisolone, and nilotinib. After achieving complete remission (CR), subjects received either 5 courses of consolidation followed by 2-year maintenance with nilotinib, or allogeneic hematopoietic cell transplantation (alloHCT) depending on the donor availability, his/her tolerability, and patient’s wish. Nilotinib was administered twice a day with a single dose of 400mg (800mg per day) from day8 of induction until the initiation of conditioning for alloHCT or the end of maintenance therapy. Minimal residual disease (MRD) monitoring was performed at the central lab with quantitative RT-PCR assays for peripheral blood BCR-ABL RNA using LightCycler® Technology in serial; at the time of diagnosis, at hematologic CR(HCR), and every 3 months thereafter. BCR-ABL quantification was expressed relative to the amount of glucose-6-phosphate dehydrogenase (G6PDH) mRNA. The molecular response was defined as complete (MCR, MRD-negative) if the BCR-ABL/G6PDH ratio was less than 1x10-6. Toxicity was graded according to National Cancer Institute Common Toxicity Criteria (version 2.0). Subjects had been followed up for 2 years after alloHCT or during maintenance therapy. Data were frozen up in June, 2013. A total of 91 subjects (male: female = 45: 46) were enrolled onto the study between January 2009 and May 2012. The median age was 47 (range 18-71) years old. Type of BCR breakpoint was minor (e1a2) in 71% of patients. The median BCR-ABL/G6PDH ratio was 6.09 (bone marrow) and 3.28 (peripheral blood) at diagnosis. During induction, all subjects required blood product transfusion, and incidence of nonhematologic adverse events (AE) over grade 3 was 17% (jaundice), 18% (ALT elevation), 13% (lipase elevation), and 2% (pancreatitis). Neither QTc prolongation over 500ms nor significant arrhythmia happened among any subject and any cycle. HCR rate was 90% and median time to HCR was 27 days (range, 13-72); most of failure was due to death in aplasia (n=8). MCR rate at HCR was 55%, Cumulative MCR rate was 84%, and median time to MCR was 1.1 months (range, 0.6-15.8). Most common cause of dropout from study was treatment-related death (n=22; during induction/consolidation vs. after alloHCT = 12 vs. 10), and HREL (n=15). Nilotinib was interrupted 75 times among 64 subjects, reduced 14 times among 12 subjects, and discontinued permanently due to hematologic relapse (HREL, n=14), AE (n=6, over gr3:3), and other cause (n=2). Fifty nine patients underwent alloHCT, 34 with myeloablative and 25 with reduced-intensity conditioning. Incidences of acute graft-versus-host disease (GVHD) and chronic GVHD were 41% and 29%, respectively. With a median follow-up of 20.7 months of surviving subjects, estimated hematologic relapse-free survival (RFS), and overall survival (OS) rate at 2 years were 74% and 70%, respectively. Among subject achieving MCR, 2-year molecular RFS rate was 56%. When events were defined as ‘dropout due to AE, isolated molecular / extramedullary relapse, HREL, and death from any cause’, median event-free survival was 12.5 months. In this prospective study, nilotinib was shown to be effective for adult Ph+ALL, and concurrent administration of nilotinib with cytotoxic drug was well-tolerable, although death in aplasia during induction was the most common cause of failure of achieving HCR. In terms of MRD, potential of nilotinib to achieve and maintain MRD negativity were satisfactory (Clinicaltrials.gov NCT00844298). Disclosures: Off Label Use: Nilotinib for Ph+ALL-sientific and academic purpose.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2013
    detail.hit.zdb_id: 1468538-3
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  • 5
    In: Blood, American Society of Hematology, Vol. 110, No. 11 ( 2007-11-16), p. 4218-4218
    Abstract: Background: Three types of PML-RARα mRNA fusion transcripts in acute promyelocytic leukemia (APL) could be existed: a short (S)-form type, a long (L)-form type or a variable (V)-form type. Whether 3 types of PML-RARα mRNA fusion transcripts associated with different manifestations and outcomes in individual APL cases are unclear. Recently, some studies reported the controversial results for the relationship between the types of PML-RARα mRNA fusion transcripts and clinical outcomes. But, there was no data about the types of PML-RARα mRNA fusion transcripts especially for the APL patients who were received remission induction therapy with AIDA. Methods: We performed a retrospective analysis for the data of 94 patients with APL, whose isoform data was available. We evaluated the differences of therapeutic outcome of remission induction chemotherapy in terms of response rate, relapse-free survival (RFS), overall survival (OS) and the association of pretreatment clinical parameter characteristics according to the PML-RARα isoforms. Results: The median age of the patients was 41 years (15–85). CR rate following remission induction treatment was 84.9% (AIDA 87.0% vs. non-AIDA 80.0%). Among 94 patients, there were 58 L-form cases (62.1%), 32 S-form cases (34.0%), 4 V-form cases (4.3%). There was no significant difference at any patient’s pretreatment characteristic according to PML-RARα isoform type. CR rate was higher in the group of initial WBC 〈 10,000/ul (93.5% vs. 65.4%, p=0.001). But there was no difference within the isoform L/S subgroup (84.2% vs. 87.2%). And OS and RFS were not different between isoform L/S subgroup (5yr 74.3% vs. 83.1%, 84.2% vs. 85.1%). AIDA induction group was better than non-AIDA induction group regarding OS and RFS (5yr 84.4% vs 55.7%, p=0.026, 90.0% vs 65.7%, p=0.007), but not significant in the multivariate analysis. And also, it was not significantly different in the OS and RFS between isoform L/S subgroup of the AIDA induction group (5yr 80.5% vs. 92.0%, 95.7% vs. 97.0%). Conclusion: This study suggests that high initial WBC count is associated with low CR rate, AIDA induction group has a trend of better OS and RFS, treatment outcomes according to PML-RARα isoform type are not different. Prospective study will be needed to confirm the meaningful significance of PML-RARα isoform type.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2007
    detail.hit.zdb_id: 1468538-3
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  • 6
    In: Blood, American Society of Hematology, Vol. 116, No. 21 ( 2010-11-19), p. 4376-4376
    Abstract: Abstract 4376 Background: Previously, we had reported that antioxidants (ie, Prx & catalase) were down regulated at the time of diagnosis but those levels were restored to the level of normal individuals as ones achieved CR with signal transduction inhibitors on primary cells of chronic myeloid leukemia(Blood 114: Abstract 1114, 2009). Meanwhile it is plausible that primary cells of acute myeloid leukemia may have different biologies comparing to chronic myeloid leukemia in terms of the regulation of ROS/Prx's and Gpx1. In this study, we investigated the changes of ROS/Prx's and Gpx1 level in the primary cells at the time of diagnosis and at complete remission of AML. In addition, we studied the level of differentiation and changes of ROS/Prx's by ATRA on NB4 cell line simultaneously to study the potential correlation between differentiation and changes of ROS/Prx's and Gpx1. Method: Pairs of bone marrow sample at the diagnosis and at hematologic remission status of AML patients were evaluated for detection of intracellular ROS using dichlorodihydrofluorescein diacetate (DCFH-DA) and immunoblot assay for the expression of Prx1-6 and Gpx1. We studied the entire process of differentiation by treatment with ATRA on NB4 cell line in vitro in time dependent manner for 4 days. Changes of ROS/Prx's and Gpx1 were evaluated and the level of differentiation was confirmed by Wright's stain simultaneously for 4 days. Result: In bone marrow samples of AML patients, intracellular ROS levels at the time of diagnosis were significantly higher than those of remission status samples. However, the expression of Prx1 and Gpx1 were increased as well at the time of diagnosis. With induction chemotherapy(3+7), elevated ROS/Prx1 and Gpx1 level came down to the level of normal volunteer bone marrow donors. In NB4 cells, intracellular ROS level were being reduced as time went on after All-trans-retinoic acid (RA) treatment showing progressive differentiation for 4 days. The level of differentiation by RA treatment was confirmed by Wright's stain in time dependent manner. Expression of Prx1 and Gpx1 were decreased after RA treatment by Western blot analysis as well. The activities of NADPH oxidase and Rac1-GTP, which are an essential component of the ROS producing NADPH oxidase, decreased in RA treated NB4 cells as time elapsed compared with control NB4 cells. Conclusion: Our data suggested that leukemogenesis of acute myeloid leukemia could be related with increased expression of ROS/Prx1 and Gpx1. Elevated level of expression on ROS/Prx1 and Gpx1 were down to the levels of BM of normal individuals as ones achieve complete remission. These findings are quite opposite with the previous observation on CML suggesting different biology in terms of ROS/Prx1 and Gpx1 dysregulation in AML. Interestingly, differentiation processes using RA in NB4 cells were correlated with decreased the expression of Prx1 and Gpx1 in time dependent manner. These data suggest the potential usefulness of differentiation agents(ie, RA and others) in AML treatment via modulation of ROS/Prx1 and Gpx1. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2010
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 7
    In: Blood, American Society of Hematology, Vol. 110, No. 11 ( 2007-11-16), p. 4539-4539
    Abstract: Background: Several investigators have recently shown that activated growth factor receptors increase the relative levels of intracellular ROS and that bcr/abl kinase induces the production of ROS in hematopoietic cells. In addition, bcr-abl kinase induces self-mutagenesis via ROS to encode IM resistance. Meanwhile, two members of the peroxiredoxin family, Prx 1 or Prx 2, efficiently lowered the intracellular level of H2O2 and blocked the induction of apoptosis by ceramide, suggesting that the Prx enzymes contribute to intracellular signaling by removing H2O2. In this study, we investigated the changse in the levels of H2O2-removing enzymes like Prxs, glutathione peroxidase 1 (Gpx1), and catalase during Imatinib (IM) therapy in CML. Methods: Mononuclear cells(MNC) were isolated by standard Ficoll-Hypaque from the bone marrow aspiration at the time of diagnosis and during treatment with IM (Gleevec, Novartis, East Hanover, NJ). Standard cytogenetics analysis and RT-PCR for Philadelphia chromosomes were performed. For immunoblot analysis of antioxidant enzymes, cell lysates were fractionated by SDS-PAGE, and the separated proteins were transferred electrophoretically to a nitrocellulose membrane (Protran, Germany) and were probed with antibodies specific for Prx I, II, VI, GPx1, or catalase (AbFrontier, South Korea). Results: Samples from the diagnosis CML patients showed significantly decreased levels of Prx I, Prx II, Prx IV, and Gpx I, but also revealed an increased level of catalase. Especially prominent was the diminished ratio of Prx II to catalase in CML patients when compared with those of normal individuals. As the level of Philadelphia chromosomes decreased to that of normal individuals as the result of IM treatment, the expression levels of Prx(s) (P=0.018) and catalase (P=0.009) were restored to the levels of normal individuals. Conclusions: Decreased Prx 2 and elevated catalase levels at the time of diagnosis are closely correlated with the elevated bcr/abl kinase level in CML. The aberrant expression of those antioxidant enzymes returned to normal with IM treatment. Now, we will attempt to develop these method(s) to assess the changes of Prx(s) and catalase on the single cell level using immunohistochemistry with monoclonal Ab(s). Understanding the molecular mechanisms of changes on antioxidant might be a potent tool in developing more effective new drugs in CML.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2007
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 8
    In: Blood, American Society of Hematology, Vol. 118, No. 21 ( 2011-11-18), p. 1517-1517
    Abstract: Abstract 1517 Background: Incorporation of imatinib into classical cytotoxic chemotherapy has improved the response and survival of patients with Philadelphia chromosome-positive (Ph+) adult acute lymphoblastic leukemia (ALL). Nilotinib (Tasigna, Novartis Pharma, Basel, Switzerland), a second-generation tyrosine kinase inhibitor with enhanced in-vitro inhibition of BCR-ABL kinase, showed faster and deeper responses than imatinib among patients with chronic myeloid leukemia. Moreover, less serious gastrointestinal adverse effects of nilotinib may be beneficial to combination with intensive chemotherapy in Ph+ ALL when compared with imatinib. Herein, we report interim results of a prospective single-arm multicenter phase-2 study evaluating the safety and efficacy of nilotinib-combined multi-agent chemotherapy in Ph+ ALL. Methods: Patients aged over 18 years old were eligible if they had newly diagnosed Ph+ ALL, and adequate hepatic/renal/cardiac function. Diagnosis of Ph+ ALL was dependent upon confirmation of t(9;22) with cytogenetics by conventional GTL-band technique, and/or positive molecular analysis with nested RT PCR for detection of BCR-ABL fusion transcripts. Written informed consent was obtained from all patients. All patients received induction treatment consisting of vincristine, daunorubicin, oral prednisolone, and nilotinib. After achieving complete remission (CR), patients received either 5 courses of consolidation followed by 2-year maintenance with 6-mercaptopurine plus methotrexate, or allogeneic hematopoietic cell transplantation (alloHCT) according to the donor availability and his/her general condition. Nilotinib was administered twice a day with a single dose of 400mg (800mg per day) from day8 of induction until the initiation of alloHCT or the end of maintenance therapy. Quantitative RT-PCR assays were performed at the central lab with Light-Cycler Technology at the time of diagnosis, at CR, and every 3 months thereafter. BCR-ABL quantification was expressed relative to the amount of glucose-6-phosphate dehydrogenase (G6PDH) mRNA. The molecular response was defined as complete (MCR) if the BCR-ABL/G6PDH ratio was less than 1×10−6. Toxicity was graded according to National Cancer Institute Common Toxicity Criteria (version 2.0). For interim analysis, outcome was updated as of July 1, 2011. Results: A total of 50 consecutive patients (male: female = 22: 28) were enrolled onto the study between January 2009 and December 2010. The median age was 44.5 (range 18–71) years old. Type of BCR breakpoint was minor (e1a2) in 66% of patients. The median BCR-ABL/G6PDH ratio was 6.09 (bone marrow) and 3.08 (peripheral blood) at the diagnosis. Except five patients who died in aplasia during induction, 45 (90%) patients achieved hematologic remission (HCR), and MCR rate was 54% at the time of HCR. During the whole treatment periods, administration of nilotinib was interrupted 50 times among 30 patients, and dose was reduced among 6 ones. Of 45 patients who achieved HCR, median dose intensity (DI) of nilotinib between day8 and day of confirmation of HCR was 769.2mg (range 160–800), and MCR rates were not different among two subgroups when dichotomized using the median dose intensity (60.9% vs. 59.1%). During the induction, 20% of patients experienced ≥grade 3 jaundice, which were all reversible, and 2% experienced pancreatitis. Thirty three patients underwent alloHCT, 19 with myeloablative and 14 with non-myeloablative conditioning. Incidences of ≥grade 3 acute graft-versus-host disease (GVHD) and extensive chronic GVHD were 9% and 3%, respectively. With a median follow-up of 17.4 months (range, 6.9–29.1), estimated relapse-free survival (RFS), event-free survival (EFS), and overall survival (OS) at 2 years were 71.1%, 49.4%, and 66.2%, respectively. Of 33 patients who underwent alloHCT, 2-year RFS, EFS, and OS rate were 70.5%, 60.0%, and 83.2%, respectively. Achievement of MCR and DI of nilotinib were not associated with outcome. Conclusion: Nilotinib was tolerable in combination with intensive chemotherapy for adult patients with Ph+ ALL, and the outcomes were comparable to previous results based on imatinib combination. Patient recruitment is ongoing currently based on this interim analysis, and the final results are expected in 2014. Disclosures: Off Label Use: Nilotinib is used as 'off-label drug' for Philadelphia chromosome-positive acute lymphoblastic leukemia in this trial. We have achieved the permission for the use of this drug in this clinical trial from the Korean FDA.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2011
    detail.hit.zdb_id: 1468538-3
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  • 9
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 3654-3654
    Abstract: Introduction: The effect of imatinib plus combination chemotherapy were assessed in 87 patients, aged 16-71 years, with newly diagnosed Philadelphia Chromosome-Positive (Ph+) acute lymphoblastic leukemia (ALL). Methods: Imatinib (600 mg/day orally) was administered continuously with combination chemotherapy, starting from eighth day of remission induction treatment, then through 5 courses of consolidation or until allogeneic hematopoietic cell transplantation (HCT). Patients who were not transplanted were maintained on imatinib for 2 years. Molecular response monitoring was performed at the central lab (Asan Medical Center) with quantitative RT-PCR assays for peripheral blood or bone marrow BCR-ABL RNA in serial; at the time of diagnosis, at hematologic complete remission (HCR), and every 3 months thereafter. The molecular response was defined as complete (MCR) if the BCR-ABL/G6PDH ratio was less than 1x10-5. Results: Between October 2005 and February 2009, total 89 patients with newly diagnosed Ph+ALL were enrolled. With median follow-up of 5 years among survivors (range: 2.6-8.9 years) and data were frozen up in July, 2014. Two patients were not assessed, one due to a final diagnosis of CML blastic phase and one for refusal of the protocol treatment 4 months after enrollment. Eighty-two patients (94%) achieved HCR at a median 25 days (range, 14-69 days). Among these 82 HCR patients, 40 experienced recurrence of leukemia and 5-year relapse free survival (RFS) rate was 36.8%. Median time of RFS was 33 months (95% CI 20-46 months). In all, 24 patients died without leukemia progression or recurrence. Causes of treatment related morality were infection (n=5), bleeding (n=2), and HCT related complication (n=17). The 5-year overall survival (OS) rate was 33.4% and the median time of OS was 22.9 months (95% CI, 7.95-37.97 months). In total, 56 patients (68%) underwent allogeneic HCT in first HCR and had received a median 2 courses (range, 0-5 courses) of consolidation prior to HCT. At a median follow-up of 5-years (range, 2.1-8.4 years) after HCT, 23 patients experienced leukemia recurrence (cumulative incidence, 59.1%; 95% CI, 49.7%-68.5%). Of these 23 patients, 17 showed new molecular evidence of disease recurrence before hematologic relapse. Six patients, however, experienced hematologic recurrence without preceding molecular evidence of leukemia recurrence. The 5-year OS rate of patient underwent allogeneic HCT at first HCR was 52.6% and the median time of OS was 72.0 months (95% CI, 17.49-126.50 months). In the patients who completed the five cycles of consolidation, 7 patients were maintained on imatinib. Among these 7 patients, four patients finished 2-year imatinib maintenance. At median follow-up of 4 years (range, 1.9-7.4 years) after maintenance, 6 patients relapsed. The median time of RFS of patient who received maintain therapy was 40.7 months (95% CI, 24.38-57.19 months). One patient with relapse received HCT at second HCR after salvage therapy and two patients died with leukemia recurrence. Cumulative MCR rate was 88.5%, and median time to MCR was 54 days (range, 13-384 days). Median time of MCR duration was 13 months (range, 0.9-60.3 months). MCR achievement within 3months after remission induction was significant predictor of RFS (P=0.004) and OS (P=0.003). Thirty two patients who lost of MCR had significantly inferior RFS (P 〈 0.0001) and OS (P=0.001) then 41 who maintained MCR. Total mean imatinib dose intensity over the entire treatment period was 80% (range, 22-110%) and mean imatinib dose intensity during remission induction was 85% (range, 22-131%). Imatinib dose intensity during remission induction; 〉 90% vs. ¡Â90%; was significantly associated with median HCR duration (44 vs. 13 months, P=0.001, Fig. 1), median overall survival (39 vs. 10 months, P 〈 0.0001, Fig. 2), and 3-year MCR rate (61% vs. 19%, P=0.001, Fig. 3). The probability for maintaining MCR at 3 years according to total imatinib dose intensity; 〉 80% vs. ¡Â80%; was 57% (95% CI, 43.0-75.5%) and 33% (95% CI, 12.3-55.4%), respectively (P=0.05). Conclusions: The higher imatinib dose intensity is correlated with the better molecular response and the superior overall outcome. The quantitative monitoring of BCR-ABL transcript levels is useful in identifying subgroups of Ph+ALL patients at a high risk of relapse. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
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  • 10
    In: Blood, American Society of Hematology, Vol. 122, No. 21 ( 2013-11-15), p. 5164-5164
    Abstract: BCR/ABL oncogenic tyrosine kinase is known to induce high levels of intracellular ROS which may further induce genomic instability with malignant transformation and even imatinib (IM) resistance. There are several lines of evidence that the production of reactive oxygen species (ROS) and the expression and activity of antioxidant enzymes make up the primary redox control of leukemia cells and cell survival. Therapies targeting the redox environment such as over-expression of antioxidants or antioxidant treatment, could inhibit tumor cell growth even resistant cells. In this study, we investigated the change of peroxiredoxin (Prx), which have a function of protection against oxidative stress, and survival of BCR-ABL positive cells during IM therapy. Methods BCR-ABL1 positive cell lines were cultured using 20% IMDM medium. We evaluated cell growth by MTT assay, and also evaluated BCR/ABL expression by western blot analysis. We also evaluated changes of intracellular ROS level and antioxidant enzymes, by immunoblot assay. siRNAs against Prx2 (100-200nM) were transfected into K562 cells using HiPerFect transfection Reagent (Qiagen) according to manufacturers’ protocol. During siRNA transfection, 1uM of imatinib was treated for 48hours. 72 hours after siRNA transfection, expression of BCR/ABL and Prx2 were detected by western blot assay and proliferation was determined by MTT assay method. Intracellular ROS was measured by flow cytometry after 10uM DCF-DA staining for 20mins. Results During IM treatment, we observed the significant decrease of cell viability and decrease of intracellular ROS level in BCR-ABL1 positive cell lines. These finding were well correlated with eradication of BCR/ABL oncogene by western blot results. The expression levels of Prx2 was restored with IM treatment and restoration of redox enzymes is correlated with reduction of BCR-ABL protein in Philadelphia positive cells. siRNAs transfected cells were not decreased cell survival even though eradication of BCR/ABL oncogene during IM treatment. Conclusion Significant change of ROS and Prx2 levels according to IM treatment are closely correlated with bcr/abl kinase level in both BCR-ABL1 positive cell lines. This finding was correlated with restoration of the level of PRX2. Those results has been implicated the possibility of therapeutic application by modulation redox system. Strategy of over-expression of Prx2 might be able to control sensitivity of the BCR-ABL1 positive cells to drug-induced apoptosis. Understanding the molecular mechanisms of changes on ROS and redox enzymes may be potential tools to develop more potent new drugs in Ph+ CML or Ph+ ALL patients especially for IM resistant. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2013
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