bluuebunny/crossref_metadata_2025_split huggingface dataset:
The AML1/ETO Target LAT2 Membrane Adaptor Molecule Is Regulated during Normal Monocytic Differentiation.
Authors: Duque-Afonso Jesus , Solari Leticia , Luebbert Michael 
Published: April 2020

Abstract
LAT2 (NTAL/LAB/WBSCR5) is a 28 KDa membrane protein which acts as adaptor molecule in the signalling pathways of FcεR I, c-Kit, B cell and T cell receptor. Bone marrow-derived mast cells from knock-out (KO) mice are hyperresponsive to stimulation via FcεR I. Although LAT2 is highly expressed in B cells, no major changes were found in function or development of B cells from LAT2 KO mice. An autoimmunity syndrome in LAT2 KO mice is caused, at least in part, by hyperreactivity and higher proliferation of T cells. Previously, we showed that LAT2 mRNA is repressed in vivo by AML1/ETO which was confirmed by others in several large series of primary AML blasts. We wished to elucidate the possible role of LAT2 during the myelopoiesis. AML1/ETO was induced by Ponasterone A in an ecdysone-inducible system in U937 cells (9/14/18 cell line). AML bone marrow samples from 43 patients (pts) were analyzed for LAT2 expression. Several myeloid cell lines were treated either with ATRA, DMSO or PMA for 3 days. Normal CD34+ cells were differentiated ex vivo by G-CSF towards granulocytes and by GM-CSF plus IL-4 towards monocytes and dendritic cells. LAT2 expression was determined by Northern and Western blot. LAT2 protein was repressed not only in AML1/ETO positive primary AML blasts (6/6), but also in blasts from patients with deletions of chromosome 7 (3/4) and the t(15;17) (4/4); expression was moderate to high in AML blasts with normal karyotype (14/15). LAT2 was expressed in normal monocytes and even higher in alveolar macrophages but not in granulocytes of healthy donors. It was downregulated after ATRA-induced granulocytic differentiation of NB4, HL60 and U937 cells but upregulated after DMSO-induced granulocytic differentiation of HL60 cells and PMA-induced monocytic-macrophage differentiation of HL60, U937 and Kasumi-1 cells. In normal CD34+ cells, LAT2 was strongly induced 7 days after the addition of G-CSF and GM-CSF+IL4 respectively, but after 14 days it was downregulated (0.7 +/− 0.4-fold) by G-CSF-induced granulocytic differentiation and upregulated (5.8 +/− 2.8-fold) by GM-CSF+IL4-induced monocytic-DC differentiation. Conditional expression of AML1/ETO in 9/14/18-U937 cells partially inhibited the PMA- and vitamin D3-induced monocytic differentiation of these cells, as determined by FACS for CD11b and CD11c. In conclusion, LAT2 protein is strongly repressed by AML1/ETO in primary leukemias and is upregulated during the monocytic differentiation in several cell lines and normal CD34+ cells. Further studies in a LAT2 knock-down by shRNAs in U937 cells are warranted to functionally address its possible role in monocytic differentiation.
The Identification and Characterization of Zebrafish Mast Cells.
Authors: Berman Jason N. , Seibert Jake , Dobson Tristan , Teh Eve , Hrytsenko Olga , Pohajdak Bill , Fraser Robert , Paw Barry , Lin Tong-jun 
Published: April 2020

Abstract
Mast cells (MCs), tissue counterparts to mammalian basophils, are known for their role in allergic reactions, inflammation and cancer progression, yet their developmental origin remains controversial due to limitations studying these cells in traditional animal models. The zebrafish provides a highly efficient system for studying vertebrate MC development. All other major hematopoietic lineages have zebrafish counterparts and the fundamental genetic mechanisms controlling hematopoiesis are well conserved. We are the first to identify zebrafish MCs in the gill and intestine. These cells demonstrate classic MC phenotypes including prominent metachromatic granules following staining with toluidine blue and positive immunohistochemical reactions to antibodies against human tryptase and C-KIT. Electron microscopy demonstrates a striking morphologic resemblance to mammalian MCs. Functional studies using the stimulating agent, Compound 48/80 or formalin-killed Aeromonas result in MC degranulation and increased blood levels of key mediators, such as tryptase. These cells also express carboxypeptidase A5 (cpa5), a zebrafish homologue of the human mast cell-specific CPA enzymes. Cpa5 expression in zebrafish embryonic blood cells begins at 24 hours post fertilization and co-localizes with a number of established granulocytic and monocytic markers suggesting that MCs arise from a common granulocyte/monocyte progenitor. Morpholino knockdown studies have demonstrated that the transcription factors gata-2 and pu.1, but not gata-1 are necessary for early MC development. Interestingly, friend of gata-1 (fog-1) may also be required, but in a gata-1 dependent manner. Ongoing morpholino and mutant rescue studies will further establish in vivo the contribution that these transcription factors make to vertebrate MC development. Finally, we have cloned a cpa5 promoter element and shown it can drive expression of the green fluorescent protein in early zebrafish MCs providing a means for generating transgenic zebrafish lines to model human MC diseases for use in high throughput small molecule modifier screens.
Kinase Suppressor of Ras Plays a Critical Role in Modulating Inflammatory Mast Cell Functions.
Authors: Chen Meng , Horn Whitney , Li Xiaohong , Knowles Scott , Ingram David , Chen Shi , Yang Feng-Chun , Clapp D. Wade 
Published: April 2020

Abstract
The Raf/MEK/extracellular signal-regulated kinase (ERK) kinase cascade and the Ras-PI3-K-Akt pathways are intricately regulated and evolutionarily conserved pathways that have been implicated in specialized cellular functions including proliferation, differentiation, survival and degranulation. Recent data suggest that the strength and duration of these signals is maintained by extracellular growth factors and integrin stimuli as well as intracellular protein scaffolds. In the present study, we investigated the role of Kinase suppressor of Ras (KSR), a scaffold that appears to regulate both Ras-Erk and Ras-PI3-K activity in influencing mast cell function. In vivo, KSR−/− mice have a 2–3 fold reduction of resident mast cells in multiple organs including the peritoneum and the skin as evaluated by scoring Alcian blue positive cells. To evaluate the mechanistic underpinnings of these in vivo observations, bone marrow derived mast cells (BMMCs) were generated and proliferation, survival, degranulation, and migration was examined. A 3–4 fold reduction in kit-ligand mediated proliferation as measured by [3H]thymidine incorporation was observed in KSR−/− BMMCs as compared to WT BMMCs. In addition, a 50% increase in apoptosis was observed in KSR−/− mast cells as compared to that in WT cells as measured by flow cytometeric analysis using Annexin/PI staining. Given that Erk and Akt are established molecular targets control proliferation and survival, respectively; we next performed western blots to evaluate if the changes in biological activity was associated with these signaling pathways. Importantly, a reduction in phosphorylation of ERK and phosphorylation of AKT was observed in the KSR −/− BMMCs as compared to that in WT BMMCs. Given the role of PI3-K signals in mediating cytoskeletal organization in mast cells, we next tested whether the reduction in PI3-K signals was associated with a reduction in degranulation and migration. Following stimulation with kit-ligand and cross-linking of the IgE receptor, KSR−/− mast cells were found to have a 30–50% decrease in b-hexosaminidase release. Moreover, KSR−/− mast cells have up to a 5 fold reduction in migration to kit-ligand as measured over a range of kit-ligand concentrations. Collectively, the in vivo and in vitro studies suggest that KSR is an important regulatory kinase that may be a viable molecular target for modulating inflammatory mast cell functions.
Flt3 Receptor Inhibition Abolishes Constitutive NFκB Activation in High-Risk Myelodysplastic Syndrome and Acute Myeloid Leukemia.
Authors: Grosjean Jennifer , Ades Lionel , Bohrer Simone , Fenaux Pierre , Kroemer Guido 
Published: April 2020

Abstract
High-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are characterized by the constitutive activation of the anti-apoptotic transcription factor NF-kappaB, via the activation of the IKK complex. We show that constitutive activation of the receptor tyrosine kinase Flt3 is responsible for IKK activation and this activation of the NF-kappaB pathway was found to involve a not yet described phosphorylation of the IKK and IkBa complex involving tyrosine residues compared to serine residues in the classical NF-kappaB pathway. Chemical inhibition or knockdown of Flt3 with small interfering RNAs abolished NF-kappaB activation in MDS and AML cell lines, as well as in primary CD34+ bone marrow cells from patients, causing mitochondrial apoptosis. Epistatic analysis involving the simultaneous inhibition of Flt3 and IKK indicated that both kinases act via the same anti-apoptotic pathway. An IKK2 mutant with a constitutive kinase activity and a plasma membrane-tethered mutant of NEMO that activates IKK1/2 prevented the cytocidal action of Flt3 inhibition. IKK2 and Flt3 physically associated in MDS and AML cells and Flt3 inhibition caused the release of IKK2 from a preferential association with the plasma membrane. Flt3 inhibition only killed CD34+ bone marrow cells from high-risk MDS and AML patients, in correlation with the blast numbers and the NF-kappaB activity, yet had no lethal effect on healthy CD34+ cells or cells from low-risk MDS. These results suggest that Flt3 inhibitors might exert an anti-neoplastic effect in high-risk MDS and AML through inhibition of constitutive NF kappaB activation.
Polymorphisms in Detoxification and DNA Repair Genes in Myelodysplastic Syndromes.
Authors: Seedhouse Claire H. , Fischer Stephanie , Germing Ulrich , Russell Nigel , Haase Detlef 
Published: April 2020

Abstract
The maintenance of genetic stability within haematopoietic stem cells is essential for normal haematopoiesis and this is emphasised by the association of leukemias and myelodysplastic syndromes (MDS) with genetic instability. DNA is normally protected from damage via a number of complex pathways including detoxification and DNA repair pathways. Inefficient processing of DNA damage may result in an increased susceptibility to leukemia and MDS. Genetic polymorphisms exist in many genes within the DNA damage processing pathways, some of which affect the cells ability to maintain genetic stability. We have studied polymorphisms in the homologous DNA repair genes RAD51 (RAD51-g135c) and XRCC3 (XRCC3-Thr241Met) and the detoxification gene GSTM1 (deletion polymorphism) in 384 MDS samples. The GSTM1 polymorphism was studied using PCR and the RAD51 and XRCC3 genotypes were assayed simultaneously using a SNaPshot technique. The genotype distributions of RAD51-g135c and GSTM1 did not differ significantly from those reported in the literature. However the distribution of the XRCC3-Thr241Met polymorphism was found to be significantly different, with an over-representation of the variant Met allele, when compared to previously published frequencies in both control and AML populations1 (Pearson Chi-square p=0.001 and 0.016 respectively). The MDS samples were further stratified with respect to FAB groups and cytogenetics. No associations were found between any of the three genetic polymorphisms and FAB type. Interestingly the XRCC3-Met variant genotype was significantly more common in MDS samples with normal karyotypes compared to aberrant karyotypes (Pearson Chi-square p=0.01). Whilst the presence of a single polymorphic variant may display only a subtle effect, polymorphic variants of more than one gene involved in the same pathway are likely to be biologically important with respect to the cellular ability to maintain genetic integrity and hence may play a role in MDS pathogenesis. RAD51, XRCC3 and GSTM1 genotypes were therefore studied in combined analyses. The triple variant genotype (RAD51-135c/XRCC3-241Met/GSTM1-null) occurred in 4.5% of MDS patients compared to 0.6% of healthy controls1 (p=0.01) implicating this genotype in MDS. Collectively these results suggest that polymorphisms in genes which process DNA damage play an important role in MDS pathogenesis, a role which may be more significant in the absence of competing karyotype alterations. 1 Seedhouse C, Faulkner R, Ashraf N, Das-Gupta E, Russell N. Polymorphisms in genes involved in homologous recombination repair interact to increase the risk of developing acute myeloid leukemia. Clin Cancer Res.2004;10:2675–2680.
PI-PLCbeta1 Expression in Patients with High-Risk Myelodysplastic Syndromes Is Affected by Azacitidine Treatment.
Authors: Finelli Carlo , Follo Matilde Y. , Bosi Costanza , Mongiorgi Sara , Clissa Cristina , Martinelli Giovanni , Baccarani Michele , Martelli Alberto M. , Cocco Lucio 
Published: April 2020

Abstract
Phosphoinositide-specific phospholipase C (PI-PLC) beta1 is a key enzyme in nuclear signal transduction, and it is involved in many cellular processes, such as proliferation and differentiation (Manzoli L et al, Prog Lipid Res, 2005). In particular, the involvement of the PI-PLCbeta1 gene in erythroid differentiation lead us to investigate this gene in patients affected by high-risk Myelodysplastic Syndromes (MDS). It is still unclear what is the pathogenesis of the evolution of MDS into Acute Myeloid Leukemia (AML), even if the presence of a mono-allelic and cryptic deletion of the PI-PLCbeta1 gene, as well as an impaired regulation of the PI3K/Akt/mTOR axis, have been recently hypothesized to be implicated in mechanisms related to the disease progression (Lo Vasco VR et al, Leukemia, 2004;Follo MY et al, Cancer Res, 2007). In the present study, we performed a relative quantification, by Real-Time Polymerase Chain Reaction (PCR) analysis, on high-risk MDS patients, at baseline and during treatment with azacitidine. Furthermore, we evaluated the expression of the PI-PLCbeta1 gene on healthy donors and the HL60 cell line, which is useful for testing the accuracy of the technology because of its low expression of PI-PLCbeta1. To analyze and quantify the levels of the two different splicing variants of the PI-PLCbeta1 gene (a and b), we used a TaqMan isoform specific approach. We studied 8 patients with high-risk MDS (IPSS risk high or intermediate-II) treated with azaciditine, 5 of them showing a favourable response to treatment (1 patient: complete remission; 2 patients: partial remission; 2 patients: haematologic improvement). During the treatment with azacitidine, the non responsive patients (3/8) did not show any significant change in the levels of PI-PLCbeta1 mRNAs, whilst all the responders showed a marked increase of the PI-PLCbeta1 mRNA as compared with their baseline amount. Interestingly, the responsive patients showed fluctuations of PI-PLCbeta1 levels that could be related to their clinical status.Our data show a correlation between azacitidine treatment and PI-PLCbeta1 signalling in high-risk MDS, hinting at the likelihood that azacitidine could affect the transcriptional activity of PI-PLCbeta1, which is indeed a key player in the control of cell cycle.
T-Cell Receptor Vß CDR3 Oligoclonality Frequently Occurs in Childhood Refractory Cytopenia and Severe Aplastic Anemia.
Authors: de Vries Andrica C.H. , Langerak Anton W. , Verhaaf Brenda , Niemeyer Charlotte Marie , Stary Jan , Schmiegelow Kjeld , van Wering Elisabeth , Beishuizen Auke , Pieters Rob , Van Den Heuvel M.M. 
Published: April 2020

Abstract
(Very) Severe acquired aplastic anemia ((v)SAA) and myelodysplastic syndrome (MDS) are rare diseases in childhood. (V)SAA is a bone marrow failure syndrome characterized by immune mediated destruction of hematopoietic progenitors. MDS is a malignant clonal stem cell disorder, in which the hypoplastic variant is, in case of absence of a cytogenetic clone, difficult to separate from (v)SAA. Recently, studies provided a “molecular signature” of autoimmunity in adult (v)SAA, by showing oligoclonality of TCR Vß CDR3 region, which is refered to as TCR Vß skewing. We investigated the value of TCR Vß repertoire analysis in pediatric MDS-RC and (v)SAA patients. Peripheral blood and/or bone marrow mononuclear samples of patients with (v)SAA (n=38), MDS-RC (n=28) and 18 controls were analysed with Vß heteroduplex analysis of extracted RNA. Skewing was found in 21/38 (55%) of the (v)SAA patients and in 17/28 (61%) of the RC patients. Seventeen patients with clinical (v)SAA showed no oligoclonality. A significant difference in TCR skewing was found between the (v)SAA + MDS-RC patients as compared to the controls (χ2 analysis, p=0.001), but not between MDS-RC and (v)SAA (χ2 analysis, p=0.8). In this study paired samples (PB and BM) of 25 cases showed a high correlation between the skewing results in both compartments (Pearson correlation, rr 0.98). In this study TCR Vß repertoire analysis did not discriminate between MDS-RC and (v)SAA. Prospective studies will be necessary to investigate whether there is a role for this molecular tool in pediatric MDS-RC for the identification of a subset of patients that is associated with auto-immunity and therfore could be treated with IST up-front, and whether it can be used for molecular response monitoring.
A Complex Karyotype but Not Monosomy 7 Is an Independent Prognostic Factor in Advanced Childhood MDS.
Authors: Gohring Gudrun , Michalova Kyra , Beverloo Berna , Betts David , Harbott Jochen , Haas Oskar , Kerndrup Gitte , Sainati Laura , Bergstraesser Eva , Hasle Henrik , Starý Jan , Trebo Monika , van den Heuvel-Eibrink Marry , Zecca Marco , Fischer Alexandra , Noellke Peter , Locatelli Franco , Schlegelberger Brigitte , Niemeyer Charlotte M. 
Published: April 2020

Abstract
Disclosure: No relevant conflicts of interest to declare.
To study the clinical significance of recurrent chromosome aberrations in childhood MDS, cytogenetic data of 394 consecutive children with refractory cytopenia (RC) (N=215), RAEB (N=141) and RAEB-T (N=38) analyzed in the regional cytogenetic reference centers and registered in the prospective study EWOG-MDS 98 between 1998 and 2005 were evaluated. At diagnosis, a karyotype could be defined in 279/394 patients (pts) (71%). No karyotype was obtained in 16% of pts with RC compared to 8% pts with RAEB and RAEB-t (p&lt;0.001). Clonal chromosome aberrations were more common in pts with advanced MDS (RAEB and RAEB-T, 61%) compared to RC (29%), and in pts with secondary (69%) compared to primary MDS (36%) (p&lt;0.001). Monosomy 7 was the most frequent aberration occurring with similar frequency in RC (47% of abnormal karyotypes) compared to advanced MDS (49%) and in primary (53%) compared to secondary (41%) MDS. In addition, aberrations typical for de novo AML such as aberrations involving 11q23 or 3q, t(6;9) and del(9q) were noted in morphologically and clinically unequivocal MDS cases. Recurrent aberrations of adult MDS like isolated del(5q), del(20q) and -Y were very uncommon indicating a different pathogenesis of these cases. In pts with advanced MDS, there was no significant difference in overall survival (OS) of pts with normal karyotype (44% ± 18) compared to pts with monosomy 7 (58% ± 19) and patients with other karyotypes (61% ± 22). However, pts with advanced MDS and a complex karyotype (defined by ≥ 3 chromosome aberrations, presence of structural aberrations and excluding clonal evolution of monosomy 7) had a shorter OS (16% ±15, p&lt;0.01). OS and event-free survival after hematopoietic stem cell transplantation (HSCT) in pts with complex karyotypes was inferior compared to that of pts with other cytogenetic aberrations (p=0.012 and 0.039, respectively). Within the group of pts with secondary MDS, complex karyotypes were found in MDS evolving from inherited bone marrow failure disorders or after radio-/ chemotherapy, but absent in familial MDS and cases evolving from acquired aplastic anemia. As shown in a multivariate Cox analysis, advanced MDS, secondary MDS, the presence of a complex karyotype and HSCT were identified as independent prognostic factors for OS. Thus, this study demonstrates the prognostic significance of cytogenetic findings in advanced childhood MDS independent of HSCT.
Myelodysplastic Syndrome: A Study of VA Population.
Authors: Matacia-Murphy Gina M. , Al Ali Najla H. , Schrager Jeffrey A. , Beg M.S. , Safa Malek M. , Komrokji Rami S. 
Published: April 2020

Abstract
Background: Epidemiology and outcome of myelodysplastic syndromes (MDS) in the United States is not well recognized. MDS became reportable to the Surveillance, Epidemiology, and End Results program (SEER) in 2001. Only one study is published examining the SEER data between 2001–2003 on MDS incidence, epidemiology and outcome. We report first study of MDS among large population in the Veteran Affair system.
Methods: There are approximately 127 VA Medical Centers diagnosing and/or treating Cancer patients. The data collected by the medical centers cancer registries is aggregated as the VA Central Cancer Registry (VACCR) and is maintained by the Chief Program Office for Oncology at VA in Washington DC. We used the VACCR to analyze VA patients with MDS diagnosed between 1995 and 2005. The data was downloaded from the database using ICD-03 histology codes for MDS. Data was entered and analyzed using bio-statistical software SPSS. Kaplan-Meier curves were used for estimates of overall survival, chi square for comparison of categorical variables and t-test for continuous variables.
Results: Between 1995 and 2005, 1411 MDS cases were registered in the VACCR database. The median age was 75 years. Among those 1379 (97.7%) were males and 1196 (84.4%) were white patients, 171 (12.1%) black, and 44 (3.5%) other race. Majority of cases were reported as MDS, NOS 935 (66.3%), Refractory anemia (RA) 180 (12.8%), Refractory anemia with ring sideroblasts (RARS) 105 (7.4%), Refractory anemia with multilineage dysplasia (RCMD) 22 (1.6%), 5 q syndrome 13 (0.9%), Refractory anemia with excess blasts (RAEB) 105 (7.4%), Refractory anemia with excess blast in transformation 17 (1.2%), and therapy related MDS (t-MDS) 34 (2.4%). No IPSS data were available. The median overall survival (OS) was 1.8 year (95% CI 1.5–2.1). The 3 year and 5 year overall survival was 30% and 22% respectively. The median OS for RA patients was 3.7 year, RARS 4.9 year and for RAEB was 0.8 year. No difference was observed in OS between whites and black (median OS 1.73 versus 2.65, p value 0.28). Their was a non statistically significant trend for improvement of OS in patients diagnosed in 2004–2005 compared to 1995–2003 (time where azacitidine and lenalidomide were approved) median OS of 3.2 versus 1.8 (p value 0.64).
Conclusion: This is the first report of MDS case series in the VA system. Outcome is similar to what is described in literature and SEER data (3 Year OS was 30% in our VA population study compared to 35% in recently published SEER data). No racial disparities are observed in outcome. A trend towards better overall survival is noted in the last 2 years since approval of new treatment options. Coding for WHO subtypes, IPSS and treatment options should be considered in all large MDS registries.