bluuebunny/crossref_metadata_2025_split huggingface dataset:
Imbalances of the 9q34 Region Downstream of ABL Gene in CML Are Associated with Blast Crisis.
Authors: Nacheva Elisabeth P. , Brazma Diana , Benson Ruth , Howard Julie , Virgil Anna , Grace Colin 
Published: October 2019

Abstract
Chronic myeloid leukaemia (CML) is a pluripotent haematopoietic stem cell disorder defined by expression of the BCR-ABL fusion gene, a constitutively activated tyrosine kinase. The fusion gene commonly results from formation of the Philadelphia chromosome after a t(9;22)(q34;q11) or related variant rearrangement. The disease follows a biphasic course with an initial benign chronic phase (CP) of 3–4 years treatable with agents such as Imatinib, followed by a rapidly fatal transformation resembling an acute leukaemia (blast crisis, BC). The CML blast crisis has been linked to a number of secondary chromosome changes leading to genome imbalances, such as additional Ph, +8, +9, iso17q. Prognostic scores based on clinical criteria (Sokal and Hasford scores) have been replaced with the discovery of other cytogenetic abnormalities occurring simultaneously at the time of translocation, such as deletions flanking the ABL/BCR breakpoint at the der(9)t(9;22) chromosome that lead to a significantly worse prognosis. We undertook array CGH analysis using an oligo based platform (Agilent) on 46 CML patients (25 CP, 19 BC & 8 in both phases) and 12 CML cell lines revealed a range of recurrent genomic imbalances. Two sets of recurrent cryptic imbalances were identified. These represented both gains and high-level amplifications affecting the 9q34.12 region immediately downstream of ABL gene, as well as losses or gains in the distal part of the 9q34-qter segment. These imbalances were found only in patients at the BC stage. Furthermore, in cases with follow-up samples, the 9q34 imbalances were present in the advanced stage of disease thus confirming their secondary nature. Among the genes found to be amplified in CML/BC is NUP-214, a nucleoporin gene, recently implicated in T-cell acute lymphoblastic leukaemia, thus suggesting an important role for cell clone survival. Confirmation of these amplifications was sought using fluorescent in situ hybridisation (FISH). A dual fusion probe targeting the ABL-NUP214 region was applied to a selection of twenty three patients with confirmed CML and features such as deletion of der(9) chromosome or resistance to treatment with Imatinib, shown to be more prone to variation within the CML phenotypeAmplification of the NUP214 region was found in five patients. These findings represent the first reports of NUP214 amplifications in CML, paving the way for future work.
Identification of a Novel Pathway in BCR/ABL Signal Transduction Involving Akt-Independent Activation of PLC-gamma/mTOR/p70-S6K.
Authors: Markova Boyka , Huber Christoph , Fischer Thomas 
Published: October 2019

Abstract
In BCR/ABL positive CML, defining new, additional therapeutic targets in the pathways, activated by BCR/ABL is critical for the development of new treatment strategies, especially for patients resistant or refractory to Imatinib. While studying the involvement of PI3K/Akt/mTOR signaling pathway in the development of such resistance we have uncovered the existence of additional, Akt-independent mechanism of activation of mTOR/p70-S6 Kinase pathway. Short term treatment with Imatinib (1μM, 4 hours) of the BCR/ABL-positive cell lines LAMA84, AR320, KCL22, K562, Ba/F3-BCR/ABL caused downregulation of p70-S6K phosphorylation and of S6 ribosomal protein phosphorylation without decreasing phosphorylation levels of Akt, as detected by Western blotting using the respective phosphorylation-specific antibodies p-p70-S6K (Thr389), p-S6 (Ser240/244) and p-Akt (Ser473). Inhibition of Akt by the specific inhibitor SH-6 (10μM, 4 hours treatment) did not affect the phosphorylation of p70-S6K and S6. These results were consistent in all analyzed cell lines, and led us to consider alternative mechanism for mTOR/p70-S6K pathway activation. One such mechanism, recently described in FGF9 signaling is a Phospholipase-C-gamma (PLCγ)-controlled Calcium signaling pathway (Wing et al., JBC, 19937–47, 2005), involving Ca/Calmodulin (CaM) and Ca/Calmodulin-dependent Kinase (CaM-K). In all BCR/ABL+ cell lines analyzed we could detect strong PLCγ activation (examined by p-PLCγ-Tyr783 antibody), which was effectively suppressed by Imatinib treatment (1μM, 4 hours). Incubation of the cells for 30 minutes with 10μM U73122, a specific PLC inhibitor, in contrast to the inactive analog U73343, significantly blocked p70-S6K and S6 phosphorylation. The actual mechanism of the Akt-independent mTOR/p70-S6K activation by BCR/ABL is not yet entirely understood. In general, PLCγ activation in turn leads to the activation of different PKC isoform and increase in Ca-dependent signaling. By employing inhibitors of Calmodulin (W7), CaM-K (KN-93) and the PKC inhibitor PKC-412 we are currently studying the participation of these molecules in the pathway. The function of PLCγ/mTOR/p70-S6K pathway for the BCR/ABL driven cells is also analyzed in proliferation (MTT) and apoptosis assays where cells are treated with Imatinib alone or in combination with U73122. Knocking down of PLCγ and other involved molecules is another approach which we will utilize to better understand the necessity/sufficiency of PLCγ for full activation of mTOR/p70-S6K pathway in the BCR/ABL+ cells, as well as the (physical) interaction of PLCγ and BCR/ABL.
In summary, we demonstrate the existence of additional, Akt-independent, PLCγ-dependent mode of activation of mTOR/p70-S6K which operates in BCR/ABL-positive cells. This alternative pathway may prove novel therapeutic targets for CML treatment.
Aberrant Regulation of Wnt/Beta-Catenin Pathway Mediators in Chronic Myelogenous Leukemia Stem Cells.
Authors: Abrahamsson Annelie , Geron Ifat , Gotlib Jason , Durocher Jeffrey , Creusot Remi , Kavalerchik Edward , Goff Daniel , Fathman C.G. , Lilleberg Stanley L. , Giles Francis , Weissman Irving , Jamieson Catriona 
Published: October 2019

Abstract
Background
Recent research suggests that self-renewing leukemia stem cells (LSC) with increased beta-catenin expression are involved in chronic myelogenous leukemia (CML) progression. We investigated whether aberrant regulation of beta-catenin destruction complex genes contributed to the enhanced self-renewal potential of CML LSC.
Methods
FACS Aria purified normal and CML hematopoietic stem cells (HSC), granulocyte-macrophage progenitors (GMP) and lineage positive cells were transduced for 48 hours with lentiviral luciferase GFP and transplanted intrahepatically into newborn RAG2−/−gama−/− mice. At 8 to 12 weeks human CD45+ cells were FACS-purified and transplanted into secondary recipients to establish a bioluminescent CML LSC model. RT-PCR for BCR-ABL was used to confirm CML engraftment. Wnt mediator mutation analysis was performed on cDNA via fluorescent denaturing high performance liquid chromatography (DHPLC) technology and SURVEYOR mismatch cleavage analysis both with the WAVE-HS System (Transgenomic, Gaithersberg, MD). Aliquots of PCR product (3-15 ul) from all samples were scanned for mutations by DHPLC and confirmed by Surveyor mismatch cleavage, and identified with bidirectional sequence analysis on an ABI 3100 sequencer using BigDye V3.1 terminator chemistry. Quantitative RT-PCR was also performed on CML progenitors using destruction complex gene specific primers. FACS analysis was performed with the aid of a FACS Aria to analyze changes in Wnt signaling pathway mediators.
Results
Advanced phase CML was typified by expansion of a GMP population with aberrantly activated beta-catenin expression, enhanced in vitro replating capacity as well as serial transplantation potential in a CML LSC bioluminescent imaging model suggesting that the GMP population was enriched for LSC (Figure 1). A targeted Wnt mutation analysis revealed a mutation in a key component of the beta-catenin destruction complex - glycogen synthase kinase 3beta (GSK) in progenitors from three of six blast crisis CML samples analyzed. Decreased GSK expression was confirmed via FACS analysis using a GSK specific antibody in three separate experiments with CML blast crisis progenitors (Figure 2). Some CML blast crisis progenitors also demonstrated a decrease in axin 2 by quantitative RT-PCR.
Conclusions
Altered expression of Wnt signaling pathway regulators, such as GSK3, may result in increased LSC self-renewal capacity and may represent novel therapeutic targets for advanced phase CML.
Figure 1. Bioluminescent Chronic Myeloneous Leukemis stem cell Model Figure 1. Bioluminescent Chronic Myeloneous Leukemis stem cell Model Figure 2. GSK FACS Analysis. Figure 2. GSK FACS Analysis.
Clinical and Functional Evidence That Drug Transporter Expression Dictates the Response to Imatinib in Chronic Myeloid Leukaemia.
Authors: Wang Lihui , Giannoudis Athina , Lane Steven , Williamson Paula R. , Pirmohamed Munir , Clark Richard E. 
Published: October 2019

Abstract
We have previously shown that imatinib is transported into cells by hOCT1. More recently, we and others have presented data that hOCT1 expression may affect the clinical response to imatinib. Here we extend these observations in two main ways: 1) We have assessed the expression of hOCT1, MDR1 (ABCB1), MRP1 and ABCG2 (BCRP) in a cohort of 70 CML patients, of which 36 achieved complete cytogenetic response (CCR), 4 partial response and 30 no cytogenetic response (NCR). Peripheral blood was taken at baseline and after 4 weeks and 3 months of imatinib treatment. hOCT1, MDR1, MRP1 and ABCG2 gene expression levels were assessed by using real-time quantitative RT-PCR on a LightCycler. Patients were allocated to high-expression and low-expression groups using the median expression as the cut-off level. With a median follow-up of 22 months (from the start of imatinib treatment), patients with high-expression of hOCT1 at baseline had better progression free and overall survival (both p=0.005, log rank test) and a higher probability of achieving CCR (p=0.001, log rank test). MDR1, MRP1 and ABCG2 expression levels at the start of treatment had no correlation with either survival or the achievement of CCR. In addition, amongst responding patients there was a trend for patients with higher MDR1 expression to have a higher incidence of later relapse, typically with the emergence of mutations in the BCR-ABL kinase domain. In 3 of 4 patients who have lost their initial CCR, the MDR1 expression levels were greater than 10% at 3 months and all 4 cases developed BCR-ABL kinase mutation. In contrast, only 4 of 28 patients who had sustained their CCR had greater than 10% of MDR1 expression and none of them had BCR-ABL kinase mutation. 2) In order to further explore the pivotal role of hOCT1 in imatinib uptake into CML cells, we have established stably transfected KCL22 CML cells with high hOCT1 expression. In comparison to untransfected and mock transfected controls, high hOCT1 expressing cells show increased uptake of the fluorescent cation 4-(4-(dimethyl-amino)styryl)-N-methylpyridinium iodide (ASP + ), 14C-TEA and 14C-radiolabelled imatinib (p=0.0002). This enhanced uptake was blocked by the hOCT1 inhibitors amantidine (p=0.0003) and verapamil (p=0.0001). Taken together, the data demonstrate that the baseline expression of hOCT1 (but not MRP1 or ABCG2) is important in dictating the clinical response to imatinib, by means of increased cellular imatinib delivery. In addition, patients with high MDR1 expression may have a higher probability of loss of imatinib response and of kinase domain mutations, and may benefit from closer surveillance of BCR-ABL transcripts and mutations.
Pleural Effusion in Patients (pts) with Chronic Myelogenous Leukemia (CML) Treated with Dasatinib after Imatinib Failure.
Authors: Quintas-Cardama Alfonso , Kantarjian Hagop M. , Munden Reginald , Talpaz Moshe , Bruzzi John , O’Brien Susan , Garcia-Manero Guillermo , Nicaise Claude , Cortes Jorge 
Published: October 2019

Abstract
Dasatinib (SPRYCEL®, BMS-354825) is a multi-targeted kinase inhibitor of BCR-ABL with significant activity in CML after imatinib failure. Dasatinib is well tolerated. The most frequent non-hematologic toxicities are gastrointestinal, rash, and fluid retention syndromes. We evaluated the incidence and outcome of pleural effusion among 131 pts with CML treated in phase I (n=50) and II (n=81) studies of dasatinib after imatinib failure or intolerance at our institution. The median age was 59 years (range, 19 to 81). Sixty-one (47%) pts were in chronic (CP), 30 (23%) in accelerated (AP), and 40 (30%) in blast phase (BP). The daily dose of dasatinib was <70 mg in 15 (11%; 8 bid, 7 qd) pts, 100 mg in 20 (15%; 10 bid, 10 qd), 140 mg in 87 (67%; 66 bid, 21 qd), and >140 mg in 9 (7%; 6 bid, 3 qd). Dasatinib was administered for a median of 42 wks (range, 4 to 120 wks). Pleural effusion occurred in 41 (31%) pts; it was grade 3–4 in 17 (13%). The median time to its development was 5 wks (range, 1 to 107). Effusion occurred in 34% of pts in CP, 34% in AP, and 32% in BP. Effusions were categorized according to the volume of lung involvement: grade 1 (<10% of one lung) occurred in 7 (17%; 5% of total) pts, grade 2 (11–25%) in 17 (42%; 13% of total), grade 3 (26–50%) in 13 (32%; 10% of total), grade 4 (51–75%) in 3 (7%; 2% of total), and grade 5 (> 76%) in 1 (2.5%; 0.7% of total) pt. Grade ≥ 3 effusion occurred in 6 pts with CP and in 11 with advanced phase CML (5 AP, 6 BP). Effusion was more frequent among pts receiving daily doses ≥ 140 mg compared to those treated at < 140 mg (34 of 41 [83%] vs 7 of 41 [17%]; p<0.0001). Effusions were bilateral in 78% and exudative in 78% of pts. Dasatinib was interrupted in 33 (80%) and dose-reduced in 29 (71%) pts. Effusion recurred in 10 (24%) of 41 pts, leading to more than one treatment interruption. Effusion was managed with diuretics in 71%, steroids in 27% (steroids plus diuretics in 12%), thoracentesis in 22% of pts and chest tube in 5%. Dasatinib was permanently discontinued due to recurrent effusion in only 3 pts. In conclusion, pleural effusion is a not uncommon, but manageable complication of dasatinib therapy, particularly among pts in advanced phases of CML receiving dasatinib doses ≥140 mg. In most cases, early identification, temporary dasatinib interruption, the use of diuretics and/or pulse steroids, and subsequent dasatinib dose reduction led to rapid resolution.
IPI-504, a Novel, Orally Active HSP90 Inhibitor, Prolongs Survival of Mice with BCR-ABL T315I CML and B-ALL.
Authors: Peng Cong , Brain Julia , Hu Yiguo , Kong Linghong , Grayzel David , Pak Roger , Read Margaret , Li Shaoguang 
Published: October 2019

Abstract
Development of mutations within the kinase domain is a major drug-resistance mechanism for tyrosine kinase inhibitors (TKIs) in cancer therapy. In CML (chronic myeloid leukemia), a disease driven by the constitutively active BCR-ABL oncoprotein, no available TKIs have been effective in treating patients with the BCR-ABL T315I mutation. Heat shock protein 90 (Hsp90) is a highly conserved, constitutively expressed molecular chaperone that facilitates folding of client proteins like BCR-ABL, and affects the stability of these proteins. Several labs have shown that Hsp90 inhibition in vitro results in the degradation of BCR-ABL T315I and induces potent killing of these cell lines. However, these results have not been demonstrated in animal models for BCR-ABL-induced CML and B-ALL (B-cell acute lymphoblastic leukemia, a disease that does not respond well to TKIs including imatinib and dasatinib). Thus, IPI-504, an orally administered Hsp90 inhibitor, was evaluated in murine models of CML and B-ALL. Treatment of mice with wild type (WT)- or T315I BCR-ABL-induced CML with IPI-504 resulted in BCR-ABL protein degradation and a decrease in circulating BCR-ABL positive cells. In response to treatment with vehicle the median survival time of WT and T315I CML mice is approximately 20 days. While the T315I CML mice were resistant to imatinib with a median survival of 21 days, IPI-504 (50 and 100 mg/kg, PO TIW) demonstrated dose-dependent prolonged survival of these mice by 30 and 70 days, respectively (p<0.001 for both doses). Both imatinib and IPI-504 similarly prolonged survival of mice with BCR-ABL-WT-induced CML. In the T315I CML mice prolonged survival of the IPI-504 treated cohort was associated with decreased peripheral blood BCR-ABL positive leukemia cells during treatment, less splenomegaly and improved pulmonary histopathlogy at necropsy. In CML mice receiving mixed BCR-ABL-WT- or T315I-transduced donor bone marrow cells, Hsp90 inhibition more potently suppressed T315I-expressing leukemia clones relative to the WT clones, consistent with in vitro studies where T315I BCR-ABL was more sensitive to IPI-504 induced degradation in cell lines than WT BCR-ABL. Combination treatment with IPI-504 and imatinib was more effective than either treatment alone in prolonging survival of mice bearing both WT and T315I leukemic cells. IPI-504 also significantly prolonged survival of B-ALL mice bearing the T315I mutation (p<0.001).
These results provide a rationale for use of an Hsp90 inhibitor as a novel approach to overcoming resistance to TKIs as well as the potential for first line combination treatment in CML patients. The potential for IPI-504 to eliminate mutant kinases via Hsp90 inhibition provides a new therapeutic strategy for treating BCR-ABL-induced CML, ALL as well as other cancers resistant to treatment with TKIs.
The Cryptic Chromosomal Deletion, del(11)(p12p13), as a New Activation Mechanism of LMO2 in Pediatric T-Cell Acute Lymphoblastic Leukemia.
Authors: Van Vlierberghe Pieter , van Grotel Martine , Beverloo H. Berna , Lee Charles , Helgason Tryggvi , Buijs-Gladdines Jessica , Passier Monique , van Wering Elisabeth R. , Veerman Anjo J.P. , Kamps Willem A. , Meijerink Jules P.P. , Pieters Rob 
Published: October 2019

Abstract
To identify new cytogenetic abnormalities associated with leukemogenesis or disease outcome, T-ALL patient samples were analyzed by means of the array-comparative genome hybridization technique (array-CGH). Here, we report the identification of a new recurrent and cryptic deletion on chromosome 11, i.e. the del(11)(p12p13), in about 4% (6/138) of pediatric T-ALL patients. Detailed molecular-cytogenetic analysis revealed that this deletion activates the LMO2 oncogene in 4 out of 6 del(11)(p12p13) positive T-ALL patients, alike patients with an LMO2 translocation (9/138). The LMO2 activation mechanism of this deletion is loss of a negative regulatory region upstream of LMO2, causing activation of the proximal LMO2 promoter. LMO2 rearrangements, including this del(11)(p12p13) and t(11;14)(p13;q11) or t(7;11)(q35;p13), were found in the absence of other recurrent cytogenetic abnormalities involving HOX11L2, HOX11, CALM-AF10, TAL1, MLL or MYC. LMO2 abnormalities, represent about 9% (13/138) of pediatric T-ALL cases, and are more frequent in pediatric T-ALL than appreciated up till now.
Imatinib Inhibits Both CD4+ T Regulatory Cells and CD8+ T Lymphocytes Specifically Directed Against the Leukemia-Associated Antigen RHAMM/CD168.
Authors: Chen Jinfei , Schmitt Anita , Chen Baoan , Rojewski Markus , Greiner Jochen , Guillaume Philippe , Dohner Hartmut , Bunjes Donald , Schmitt Michael 
Published: October 2019

Abstract
Imatinib mesylate (IM, STI571, Gleevec®) is highly effective in the treatment of patients with chronic myelogenous leukemia (CML). In patients with residual disease or relapse after allogeneic stem cell transplantation (allo-SCT), the optimal strategy is a matter of debate: donor lymphocyte infusions (DLIs) alone, IM alone or a combination of both have been administered to CML patients in this clinical situation. As an impairment of anti-viral CD8+ T lymphocyte function by IM has been described, we questioned whether IM also affects specific anti-leukemic CD8+ T lymphocytes. Moreover, we asked to which extent CD4+CD25hi T regulatory cells might be affected by IM thus changing the balance between cytotoxic and tolerogenic T cells. After mixed lymphocyte peptide culture (MLPC), we assessed CD8+ T cells from healthy donors and patients with CML after allo-SCT by tetramer staining/multi-color flow cytometry and enzyme linked immunosorbent spot (ELISPOT) assays, as well as CD4+CD25hicells after 3 days of culture with anti-CD3 and anti-CD28. The release of interferon gamma and granzyme B by CD8+ T lymphocytes specific for R3 (ILSLELMKL), a T cell epitope peptide derived from the leukemia-associated antigen designated RHAMM/CD168 (receptor for hyaluronic acid mediated motility) was inhibited by IM in a clearly dose-dependent fashion in a range from 1 to 25 μM. These T cells were further characterized as CD8+ HLA-A2/R3_tetramer+ WT1_tetra-CD45RA+CD27-CD28-CCR7- effector T cells with the ability to lyse R3 peptide labeled T2 cells and CD34+ CML progenitor cells. The inhibition of CD8+ T lymphocytes was a function of the time of exposure to IM and reversible after removal of IM from the MLPC. On the other hand, the proliferation and function of CD4+CD25hiFoxP3+GITR+TGFß1+ CD69+CD152+ T regulatory cells were also significantly inhibited by IM in a dose-related fashion. These findings suggest that the clinical impact IM must not necessarily result in a reduced efficacy of the graft-versus-leukemia effect observed after allo-SCT and/or DLIs but might depend rather on the ratio of CD8+ cytotoxic T cells and CD4+CD25hi T regulatory cells.