bluuebunny/crossref_metadata_2025_split huggingface dataset:
Post-Remission Therapy with Imatinib and HAM Improve MRD before Tansplant for Patients with Philadelphia-Positive Acute Lymphoblastic Leukemia (Ph+ALL): Results of the GRAALL AFR03 Study.
Authors: Leguay Thibaut , Witz Francis , De Botton Stéphane , Gabert Jean , Cayuela Jean-Michel , Macintyre Elizabeth , Preudhomme Claude , Fegueux Nathalie , Thomas Xavier , Cahn Jean-Yves , Escoffre Martine , Delannoy Andre , Ifrah Norbert , Dombret Herve , Pigneux Arnaud 
Published: October 2019

Abstract
Combination of Imatinib with chemotherapy has been reported as very promising for patients with Ph+ ALL. In this study, we attempted to minimize the MRD (Minimal Residual Disease) level before transplant for Ph+ ALL by combining Imatinib with HAM (HAMI). This regimen consisted to Cytarabine 2g/m2/12 hours between day1 and day4, Mitoxantrone 10mg/m2/day between day1 and day3 combinated with Imatinib (3 different doses) between day1 and day45. MRD was studied by RT-PCR at day1 (before treatment) and day45 (after treatment) and was exprimed by BCR-ABL/ABL levels. Between April 2002 and September 2005, 36 patients in complete remission (CR) after induction chemotherapy have been analysed. This group consisted of 13 females and 23 males with a median age of 42 years (19–60). Three doses of Imatinib (400 mg, 600 mg and 800 mg/day) have been tested for six patients in each cohort (the first eighteen patients). After an intermediate analysis, the dose of 800 mg per day has been shown to be toxic (one grade IV hypokaliemia), and a last cohort of 18 patients were treated with 600 mg/day. No toxic-death related to HAMI regimen was reported. Thirthy-one patients could be studied for MRD before and after HAMI consolidation. Four patients were in molecular remission (level of BCR-ABL/ABL<10−5) before treatment and 12 after. No difference between 3 cohorts of dose was observed. The median level of MRD was 10−3 (0–0.7) and 3 × 10−5 (0–0.004) before and after treatment respectively (p=0.0015). After a median follow-up of two years and for all patients, the estimated overall survival (OS) and disease free survival were respectively of 71% (51%–84%) and 52% (32%–69%). The cumulative incidence of relapse and the cumulative incidence of death in CR were respectively of 15% (6%–32%) and 31% (17%–52%). Twenty patients had allogenic matched transplantation (thirteen related, seven unrelated) and composed the group with donor. In this first group, seven patients obtained MRD negativity after HAMI treatment. The others sixteen patients composed the second group of patients without donor or older than 55 years. In this second group, eleven patients received autologous stem-cell transplant followed by imatinib for nine of them, and five received imatinib in maintenance with or without chemotherapy. In this group, six patients had obtained MRD negativity after HAMI. The two-years OS was identical for patients with or without donor (71%). In conclusion, imatinib combined with high dose chemotherapy improved molecular remission before transplantation and lead to an improve outcome.
Prognostic Factors for Relapsed Childhood Acute Lymphoblastic Leukemia (ALL): A Report from Tokyo Children’s Cancer Study Group (TCCSG) Study L95-14 and L-99-15.
Authors: Ogawa Chitose , Ohara Akira , Manabe Atsushi , Koh Katsuyoshi , Kaneko Takashi , Goto Hiroaki , Ota Setsuo , Hanada Ryoji , Tsuchida Masahiro 
Published: October 2019

Abstract
More than 70% of children with ALL enjoy a long-term event-free survival (EFS), however, the rest of them still suffer from a relapse and the treatment for relapsed ALL is not always successful. The treatment results of childhood ALL with a first relapse were retrospectively analyzed to determine prognostic factors.
Of the 1336 children enrolled on the TCCSG L95-14 and L99-15 studies, diagnosed between 1995 and 2003, 224 suffered from a relapse before March 2005. The relapsed patients were treated differently according to the protocol of each institution. The potential prognostic factors examined were : the age (low; 1–9 years, high; over 10 years), white blood cell count (low; <50,000/μl, high; others) and immunophenotype of leukemic blasts at initial diagnosis (B-lineage or T), gender, initial risk groups, the site of relapse, the timing of relapse (very early: within 18 months after diagnosis, early: other than either very early or late relapse, late: later than 6 months after the discontinuation of the front-line chemotherapy), and the treatment after relapse (chemotherapy alone or chemotherapy plus SCT).
The sites of relapse were: isolated bone marrow (BM, n=165), BM with other sites (n=21) and extramedullary only (n=38). Ninety-nine relapses occurred in very early stage, 43 in early stage and 82 in late stage. Twenty-three patients received SCT before relapse according to the protocol.
A second complete remission (2CR) was achieved in 175/220 patients (79%) and 74 of them are still in 2CR. Five-year EFS for all the relapsers was of 29±3% (mean±s.e.) and 5-year overall survival rate was 38±4%. In a subset of patients (n=126) with B-lineage phenotypes and with isolated BM relapse, who were treated with chemotherapy alone before relapse, we found 2 significant prognostic factors identified by a multivariate analysis : the age at initial diagnosis (EFS: age low; 35±5%, high; 8±8%, p=0.0016) and the timing of relapse (EFS: late; 39±8%, early; 24±9%, very early; 16±5%, p=0.0051). Gender, initial leukocyte count, or the use of SCT after obtaining 2CR was not related with patient’s outcome in a multivariate analysis.
The importance of the timing of relapse was overwhelmingly shown, however, the significance of the age at the diagnosis was not demonstrated before. The results will be incorporated into our next protocols to relapsed patients with ALL.
Targeting the mTOR Pathway Suppresses the Growth of Acute Myeloid Leukemia (AML) Progenitors and Enhances Arsenic Trioxide Induced Antileukemic Responses.
Authors: Altman Jessica K. , Sassano Antonella , Yoon Patrick J. , Redig Amanda J. , Katsoulidis Efstratios , Tallman Martin S. , Platanias Leonidas C. 
Published: October 2019

Abstract
-Background: A limiting factor for the use of arsenic trioxide (As2O3) in the treatment of non-APL subtypes of AML is the requirement of very high concentrations for the induction of leukemic cell death. The mammalian target of rapamycin (mTOR) is a key cellular regulator of multiple signaling events that control initiation of mRNA translation in leukemia cells. We examined the effects of As2O3 on mTOR-dependent cellular pathways in AML cells and determined whether modulation of the mTOR pathway sensitizes them to the antileukemic properties of As2O3.
Methods: The human AML cell lines KG1, U937, or MM6 were treated with increasing concentrations of As2O3. Activation of p70 S6 kinase (p70S6K) was evaluated by immune-complex kinase assays in anti-p70S6K immunoprecipitates, while phosphorylation of various downstream mTOR effectors was assessed by immunoblotting with specific antibodies against phosphorylated S6 ribosomal protein (rpS6) and the translational repressor 4E-BP1. MTT assays were used to assess proliferation of the various cell lines, while apoptosis was determined by annexin V-propidium iodide staining. Finally, bone marrow mononuclear cells from patients with AML were used in clonogenic assays in methylcellulose to assess the effects of As2O3 and/or rapamycin on leukemic progenitor cell growth.
Results: Treatment of AML cells with As2O3 resulted in activation of the p70 S6K and phosphorylation of its downstream effector, rpS6, on Ser240/244, and such events were mTOR-dependent. In addition, the translational repressor 4E-BP1 was phosphorylated on Thr37/46 and Thr70, sites whose phosphorylation is required for 4E-BP1 de-activation and dissociation from eIF4E. Pharmacological inhibition of mTOR activity blocked the growth of AML cell lines as determined by MTT assays, while the addition of As2O3 to the cultures further enhanced the inhibitory effects of rapamycin. On the other hand, AS2O3-dependent induction of apoptosis was not enhanced by rapamycin in AML cells, suggesting selective effects on cell cycle and growth inhibition. Rapamycin also inhibited leukemic CFU-GM progenitor colony formation from 6 AML patients and enhanced the suppressive effects of AS2O3 on leukemic progenitor cell growth.
Conclusions: Paradoxically, As2O3 activates the pro-growth and pro-survival mTOR pathway in AML cells. Such activation appears to occur in a negative feedback regulatory manner to compensate for AS2O3 responses. Thus, combinations of AS2O3 with mTOR inhibitors may be an effective approach to overcome AS2O3-resistance in AML cells.
Acute Myeloid Leukemia-Derived Dendritic Cells Express the Immunoregulatory Enzyme Indoleamine 2,3-dioxygenase.
Authors: Curti Antonio , Pandolfi Simona , Aluigi Michela , Ferri Elisa , Ottaviani Emanuela , Durelli Ilaria , Horenstein Alberto L. , Fiore Francesca , Massaia Massimo , Piccioli Milena , Pileri Stefano A. , Martinelli Giovanni , Baccarani Michele , Lemoli Roberto M. 
Published: October 2019

Abstract
Acute myeloid leukemia (AML) cells may be differentiated into dendritic cells (DC) which have increased immunogenicity, but retain some immunosuppressive features of leukemic cells. Indoleamine 2,3-dioxygenase (IDO) enzyme, which catalyzes the conversion of tryptophan into kynurenine, has been identified as a novel immunosuppressive agent by inhibiting T-cell proliferation and is involved in tolerance induction to tumors. We have recently shown that IDO protein is constitutively expressed in a significant subset of newly diagnosed AML patients, resulting in tryptophan catabolism along the kynurenine pathway and in the inhibition of allogeneic T-cell proliferation. We, then, in vitro generated DCs from 7 AML samples (AML-DCs) in the presence of GM-CSF, IL-4 and TNF-α. The cells we obtained were morphologically and phenotypically semi-mature DCs expressing CD40, CD80, CD86, HLA-DR and CD1a molecules and they were more efficient to induce T-cell proliferation and type 1 cytokine production than primary AML blasts. At baseline, 5/7 AML samples expressed IDO, whereas 2/7 did not. After differentiation into DCs, IDO+ AML samples showed an up-regulation of IDO mRNA and protein, and IDO− AML cells turned positive. IDO-expressing AML-DCs were capable to catabolize tryptophan into kynurenine metabolite and, functionally, they inhibited allogeneic T-cell proliferation through an IDO-dependent mechanism. These data identify IDO-mediated catabolism as a tolerogenic mechanism in AML-DCs and have clinical implications for the use of AML-DCs as cellular vaccine against leukemia.
Targeting Mutant Nucleophosmin (NPM)1: A Promising Approach To Induce Growth Inhibition and Differentiation in Human AML.
Authors: Herger Bryan , Fiskus Warren , Rao Rekha , Bhalla Kapil 
Published: October 2019

Abstract
NPM1 is a nucleolar phosphoprotein that functions as a molecular chaperone for both proteins and nucleic acids and is capable of histone and nucleosome assembly. NPM1 shuttles between nucleus and cytoplasm, but is mutated and aberrantly localized to the cytoplasm in 35% of patients with AML. NPM1 is involved in regulating the activity of p53 and p14ARF, such that cells lacking NPM1 show decreased p14ARF. Mutant (m) NPM1 contains a 4-base insert that results in extra C-terminal residues encoding a nuclear export signal (NES). This causes mNPM1 to remain in the cytoplasm. In AML, mNPM1 has been correlated with the presence of FLT3-ITD and normal karyotype. NPM1 maps to 5q35 locus, which is often deleted in myelodysplastic syndrome. The role of the cytosolic mNPM1 in the pathogenesis of AML is not clear. In the present studies we determined the expression and biologic effects of mNPM1 in cultured and primary AML cells. Mutant nucleophosmin can be readily identified by reverse transcription followed by amplification with PCR primers specific for the mutant sequence. Sub-cellular fractionation and immunoblot analysis and/or immunoflourescent microscopy, as well as RT-PCR to detect the mNPM1 transcripts, confirmed that mNPM1 is localized in the cytosol in the cultured AML OCI-AML3 but is unmutated and nuclear in HL-60 cells. As compared to control siRNA, treatment with siRNA to NPM1 for 72 hours significantly induced p21 expression, inhibited cell proliferation and induced morphologic differentiation of OCI-AML3 cells. NPM1 siRNA did not induce significant apoptosis or loss of cell viability as determined by trypan blue uptake assay. OCI-AML3 cells co-express HoxA9 and Meis1 proteins, which are known to be leukemogenic in mouse myeloid progenitor cells. Notably, treatment with NPM1 siRNA depleted Meis1 and HoxA9 expressions in OCI-AML3 cells. Treatment with leptomycin B (5 nM for 48 hours), an inhibitor of the NES receptor CRM1/exportin-1, shifted the localization of mNPM1 from the cytosol to nucleus and also depleted the levels of Meis1 and HoxA9 in OCI-AML3 cells. Meis1 is known to transactivate FLT3 tyrosine kinase in AML progenitor cells, and a significant association of FLT-3-ITD with the presence mNPM1 has been documented. In the present studies, of the 16 primary AML samples, four that expressed FLT3-ITD also demonstrated expression of mNPM1. Taken together, these findings suggest that abrogation of the levels or reversing the aberrant cytosolic localization of mNPM1 may be a promising anti-leukemia treatment strategy, especially for targeting AML that co-express FLT3-ITD and mNPM1.
Replicative Senescence in Good-Risk Acute Myeloid Leukemia.
Authors: Zijlmans Mark , Swiggers Susan , Rife Soler Maria , Beverloo Berna 
Published: October 2019

Abstract
Immortal cell growth is considered the hallmark of tumor cells. In contrast, normal cells have a limited proliferative capacity of 40–60 cell divisions, also known as the Hayflick limit. The limited proliferative capacity of normal cells relates to gradual telomere shortening as a consequence of the end-replication problem. Upon critical telomere shortening, cells enter a non-replicative but viable state referred to as replicative senescence. These replicative senescent cells stain blue in a beta-Galactosidase assay and activate DNA double-strand break repair pathways at telomeres (e.g. gamma-H2AX foci). In human fibroblast models, escape from senescence results from loss of p53 and Rb function. Escape is associated with reactivation of telomerase. High levels of telomerase, as observed in germ cells and most tumor cells, allow for immortal cell growth. Recently, we demonstrated low levels of telomerase in AML patients with t(8;21) or inv(16) (Swiggers et al, G.C.C. 2006). Interestingly, levels of telomerase in these AML samples were similar to levels of telomerase in normal bone marrow progenitor cells. We hypothesized that AML without re-activated telomerase may still have intact senescence pathways that limit the proliferative capacity of normal cells. This hypothesis was addressed by studying AML patient samples without telomerase re-activation, i.e., t(8;21), t(15;17) or inv(16) (n=10), and a control group of AML with telomerase re-activation (multiple gains/losses of genetic material, n=8). AML samples werelong-time cultured in vitro in the presence of hematopoietic growth factors (range 3–6 weeks),analyzed in vivo following transplantation in NOD-SCID mice andin patients at time of relapse.
Cells with all characteristics of replicative senescence, i.e. enlarged, viable, non-proliferating, blue-coloring in beta-Galactosidase assay, critical short telomeres and gamma-H2AX foci at telomeres, were clearly observed in all AML samples with t(8;21), t(15;17) or inv(16). Gradual telomere shortening was observed in these AML cells in vitro upon long-term culture, in vivo after transplantation in NOD-SCID mice and in vivo in patients at relapse compared to time of diagnosis, indicating that these AML cells do not have an adequate telomere maintenance mechanism. We conclude that AML cells with t(8;21), t(15;17) or inv(16) are characterized by intact pathways that induce replicative senescence. Intact pathways that limit proliferative lifespan may be critical to the high cure rates following chemotherapy treatment of patients with good-risk AML.
The JAK2-V617F Mutant Found in Myeloproliferative Disorders and Acute Myeloid Leukemia Cooperates with the EpoR, but Not with FLT3 To Promote Proliferation of IL-3 Dependent Cells.
Authors: Kaza Seshu K. , Vempati Sridhar , Carola Reindl , Hiddemann Wolfgang , Spiekermann Karsten 
Published: October 2019

Abstract
The Janus Kinase (JAK) 2 mutation V617F can be detected in patients with polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) as well as at low percentages in other myeloproliferative disorders (MPDs) and myelodysplastic syndromes (MDS) and in 5–6% of de novo AML. Moreover, a recent study showed that JAK2 complemented by an additional signal of KIT or FLT3 confers self renewal capacity to hematopoietic cells. Since the JAK2V617F mutation is found in AML, we asked whether JAK2 might cooperate with FLT3, a receptor tyrosine kinase that is overexpressed in most patients with AML to induce proliferation.
JAK2-WT and JAK2V617F did not confer factor independent growth when expressed in IL-3 dependent Ba/F3 cells. Further, exploring the coordination of JAK2 and its mutant with the type I cytokine receptor EpoR, Ba/F3 cells co-expressing both JAK2 and EpoR showed proliferation in the presence of Epo but not in the absence of Epo. In contrast Ba/F3 cells co-expressing JAK2V617F and EpoR have a profound proliferation advantage and are able to grow in the absence of Epo. These data provide strong evidence that JAK2V617F has transforming potential in the presence of a type I cytokine receptor. The coexpression of the JAK2V617F mutant with a class III cytokine receptor like FLT3, which is involved in the pathogenesis of acute myeloid leukemia (AML), does not result in an increased proliferative response. Both, JAK2-WT and JAK2V617F expressing Ba/F3 cells were able to survive in the presence of the FLT3 receptor, but did not show autonomous growth.
Analysis of signaling pathways showed that the JAK2-V617F mutant, but not JAK2-WT is able to activate STAT5 in cooperation with the EpoR and FLT3.
Our data show that the JAK2-V617F mutant which is found in 5–6% of AML patients cooperates with the EpoR, but not with FLT3 to promote proliferation in IL-3 dependent cells.
Destabilization of the Factor V B-Domain Results in Procofactor Activation.
Authors: Camire Rodney M. , Zhu Hua , Bos Mettine H.A. , Toso Raffaella 
Published: October 2019

Abstract
A hallmark of hemostasis is that proteins involved in the formation of a blood clot remain in a quiescent state and are only activated following an appropriate stimulus. Blood coagulation factor V (FV), which is structurally homologous to FVIII, cannot function in the prothrombinase complex and is thus considered a procofactor. Thrombin catalyzes the conversion of FV to FVa following three cleavages (Arg709, Arg1018, and Arg1545) releasing a large heavily glycosylated central B-domain (836 amino acids). Explanations as to how bond cleavage or B-domain release facilitates the transition to the active species are incomplete. Recent studies using a partial B-domainless form of FV (FV-810 des811–1491) support a model in which removal of B-domain sequences from FV rather than specific proteolysis underlies the mechanism by which cofactor function is realized. This single-chain derivative is functionally equivalent to FVa suggesting that the deleted B-domain sequences somehow suppress cofactor activity. To investigate this further, we have expressed and purified several single-chain derivatives of FV that vary in B-domain length from 155 to 497 residues. Functional activity assays as well as direct binding fluorescent measurements revealed that elimination of most of the C-terminal half of the B-domain (residues 1034–1491; 458 out of 836 a.a. deleted) had no influence on maintaining the procofactor state. However, deletion of sequences from the N-terminal half of the B-domain resulted in derivatives with cofactor-like properties. Using progressively finer deletion variants we were able to demonstrate that either a B-domain length of at least 378 amino acids or specific sequences contained within residues 902–1033 is sufficient to suppress cofactor activity. To examine these possibilities, we constructed additional FV variants in which a B-domain length of 378 amino acids was maintained, but specific portions of 902–1033 were exchanged with FVIII B-domain. Using the FV-1033 derivative (residues 1034–1491 of B-domain deleted) as a scaffold, three constructs were prepared, s-131, s-104, and s-46, representing 131, 104, and 46 amino acids from the FV B-domain exchanged with FVIII B-domain. In activity assays and direct binding measurements, each of these variants had properties consistent with the cofactor-like form indicating that a length of ~375 residues is not sufficient to maintain the procofactor state. These findings demonstrate for the first time that there are indeed specific FV-B domain sequences between 902–1033 that directly or indirectly stabilize the procofactor state. Remarkably, simply replacing these sequences in FV-1033 resulted in activation of the proteins in the absence of proteolysis. These observations change existing ideas about FV activation and provide insight into specific regions of the B-domain that assist in preserving the procofactor state.