bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Polymorphisms in Oxidant Metabolism and DNA Repair Pathways and Risk of Leukemia and Transient Myeloproliferative Disorder in Children with Down Syndrome
Authors: Rayburg Melissa S , Kim Mi-Ok , Alonzo Todd , Gerbing Robert , Radloff Gretchen A , Davies Stella M , Gamis Alan , Perentesis John 
Published: April 2020

Abstract
Children with Down syndrome can have a wide range of developmental abnormalities related to the presence of additional genetic material from a small region of chromosome 21. Additional copies of the Cu/Zn superoxide dismutase gene and related genes at this locus are believed to contribute to high oxidative stress, and increased endogenous DNA damage and deficient repair observed in cells from patients with Down syndrome. Children with Down syndrome also have a markedly increased risk for the development of serious hematological disorders, including an approximately 20-fold increased risk for the development of acute myeloid leukemia (AML). In addition, in early infancy, as many as 10% may develop a transient myeloproliferative disorder (TMD). The basis for this overall increased risk is unknown, as are the risk factors influencing which specific patients with Down syndrome develop AML/TMD. We sought to test the hypothesis that functional polymorphisms in genes involved in oxidant metabolism and DNA repair contribute to the increased risk of AML and TMD in children with Down syndrome. We studied functional polymorphisms in the oxidant metabolizing enzyme NADPH quinone oxidoreductase 1 (NQO1), and in the DNA repair proteins X-ray repair cross complementing 1 protein (XRCC1) and Fanconi anemia complementation group A protein (FANCA). Genotyping was conducted in 170 patients with Down syndrome AML or TMD, and 202 healthy blood donor controls. All genotype frequencies in the control populations were consistent with those expected from Hardy-Weinberg equilibrium. We found that the variant NQO1 Pro187Ser allele, associated with reduced quinone reductase activity, occurred with a greater frequency in the Down syndrome AML/TMD patient population compared to healthy controls (OR, 1.61; 95% CI, 1.067–2.426; p=0.0231). The FANCA-1501 variant allele frequency was observed more frequently in Down syndrome AML/TMD patients compared to healthy controls (OR, 1.77; 95%CI, 1.220–2.568; p=0.0025). The variant XRCC-1 Arg399Gln allele was observed less frequently in the TMD/DS AML population as compared to controls (OR, 0.536; CI, 0.354–0.811; p=0.0031). These latter findings parallel the observation of a protective effect against AML in non-Down syndrome individuals with at least one copy of the XRCC-1 Arg399Gln allele (Seedhouse et al. Blood2002, 100:3761). Conclusion: These preliminary studies, representing the only reported data in Down Syndrome TMD/AML patients, suggest that functional polymorphic variants of the NQO1, FANCA, and XRCC1 genes involved in oxidant metabolism and DNA repair may influence the risk for developing leukemia. Studies involving future cohorts will be needed to confirm these observations.
Perfect Engraftment after Fludarabine, Cyclophosphamide Plus Thymoglobulin Conditioning Regimen for Unrelated Transplantation in Severe Aplastic Anemia: Phase II Prospective Multi-Center Study in Korea
Authors: Kang Hyoung Jin , Shin Hee Young , Park Jun Eun , Lim Young Tak , Chung Nak Gyun , Cho Bin , Kim Hack Ki , Kim Sun Young , Lee Young Ho , Yoo Keon Hee , Sung Ki Woong , Koo Hong Hoe , Im Ho Joon , Seo Jong Jin , Park Sang Kyu , Ahn Hyo Seop 
Published: April 2020

Abstract
Anti-thymocyte globulin (ATG) has been used in severe aplastic anemia (SAA) as a part of the conditioning regimen. Among the many kinds of ATG preparations, thymoglobulin had been found to be more effective in preventing graft-versus-host disease (GVHD) and rejection of organ transplants. After the promising result of the pilot study (Bone Marrow Transplant. 2004. 34; 939), phase II prospective multi-center clinical trial was performed with fludarabine, cyclophosphamide plus thymoglobulin conditioning regimen to allow good engraftment in unrelated transplantation for SAA. Twenty-eight patients underwent bone marrow (N=15) or mobilized peripheral blood (N=13) transplantation with cyclophosphamide (50 mg/kg once daily i.v. on days −9, −8, −7 & −6), fludarabine (30 mg/m^2 once daily i.v. on days −5, −4, −3 & −2) and thymoglobulin (2.5 mg/kg once daily i.v. on days −3, −2 & −1) from HLA matched unrelated donors. GVHD prophylaxis regimen was composed of cyclosporine (or tacrolimus), methotrexate, with or without low dose thymoglobulin (1.25 mg/kg once daily i.v. on days 7, 9 and 11). The median infused cell dose of nucleated cells and CD34 positive cells were 6.8×10^8/kg (1.3– 39.9×10^8/kg) and 5.2×10^6/kg (1.2–27.0×10^6/kg), respectively. The median number of days required for ANC of more than 0.5×10^9/l and 1.0×10^9/l were 14 days (10–35 days) and 15 days (11–40 days), respectively. The spontaneous platelet recovery to more than 20×10^9/l required a median of 22 days (22–182 days). Donor type hematologic recovery (donor type chimerism more than 90%) was achieved in all patients. Fourteen patient developed grade II–IV acute GVHD. The event free survival (EFS) was 73% and all events were transplantation related mortality (TRM) which included coagulopathy (N=3), PTLD (N=2), pneumonia (N=1), and myocardiac infarction (N=1). The EFS of patients who received bone marrow (65%) was not different from that of patients who received mobilized peripheral blood (82%) (P=0.37), but the EFS of patients who received immunosuppressive therapy (IST) previously (55%) was lower than that of patients who didn’t receive IST (92%), significantly (P=0.04). Fludarabine, cyclophosphamide plus thymoglobulin conditioning allows for the promising result of very good engraftment, although serious events occurred in some patients. We are now planning to start new multicenter study to decrease TRM by reducing the dose of cyclophosphamide.
Rituximab Plus Hypercvad Alternating with High Dose Methotrexate and Cytarabine for Patients with Newly Diagnosed Mantle Cell Lymphoma. A Multicenter Trial from GISL
Authors: Merli Francesco , Luminari Stefano , Ilariucci Fiorella , Stelitano Caterina , Petrini Mario , Di Renzo Nicola , Angrilli Francesco , Carella Angelo Michele , Barbolini Elisa , Federico Massimo 
Published: April 2020

Abstract
BACKGROUND. Rituximab plus HyperCVAD alternating with High Dose Methotrexate and Cytarabine (R-HCVAD) has been tested in patients with newly diagnosed Mantle Cell Lymphoma (MCL) with promising results (Romaguera et al. JCO 2005). In 2005 the Gruppo Italiano Studio Linfomi (GISL) started a phase II multicenter study investigating clinical activity and toxicity of R-HCVAD in a similar group of patients.
PATIENTS AND METHODS. To be included in the trial patients must have histologically confirmed diagnosis of MCL, be younger than 70 years, have adequate organ function. Chemotherapy consisted of rituximab plus fractionated cyclophosphamide, vincristine, doxorubicine, and dexamethasone(considered one cycle) alternating every 21 days with rituximab plus high dose methotrexate-cytarabine (considered one cycle) for a total of eight cycles per the MD Anderson protocol. Patients with baseline PCR positivity for t(11;14) on bone marrow (BM) had to perform PCR assessment of BM at evaluation of response and during follow-up. Only patients achieving partial response (PR) were to be addressed to HDC followed by ASCT.
RESULTS. Thirty-two patients were enrolled. There were 23 males and 9 females; median age was 54 yrs (29 to 66), 80% were in stage IV, 50% and 71% had Gastrointestinal (GI) and BM involvement, respectively; PCR for t(11;14) was positive on BM in 51% of cases. Seven patients did not complete treatment due to toxicity; of these, two patients died (one with septic shock at cycle 1, one with pulmonary aspergillosis at cycle 4), one patient had thrombosis of central line extended to right atrium at cycle 1, one had grade IV skin reaction at cycle 3, one had a severe pneumonia at cycle 1, two had persistent grade IV hematological toxicity after cycle 1 and 5, respectively. All patients had grade III–IV hematological toxicity. Response was assessed in 17 patients with 16 CR and 1 PR. PCR for t(11;14) negativity on BM was achieved in 4/9 patients after cycle 4 and in 8/9 after cycle 8. After a median follow-up of 24 months 1 patient progressed at 6 months and 1 patient relapsed after 26 months of follow-up. Two-year Failure Free Survival (FFS) was 75% (IC95% 53 to 87) and 2 year Disease Free Survival was 93%(IC95% 59–99).
CONCLUSIONS. Though longer follow-up is needed R-HCVAD regimen used in our multicenter setting confirmed high efficacy in terms of response (both clinical and molecular) and FFS. However the regimen was associated to a severe toxicity profile that caused treatment discontinuation in several patients and that may limit its use in the clinical setting.
High Frequency of RPL11 Gene Mutation in Italian Patients with Diamond-Blackfan Anemia
Authors: Quarello Paola , Garelli Emanuela , Carando Adriana , Campagnoli Maria Francesca , Brusco Alfredo , Dianzani Irma , Ramenghi Ugo 
Published: April 2020

Abstract
Diamond Blackfan anemia (DBA, MIM#205900) is a rare, pure red blood cell aplasia of childhood due to an intrinsic defect in erythropoietic progenitors. About 40% of cases show malformations. Anemia is corrected by steroid treatment in half of the patients; non-responders need chronic transfusions or stem cell transplantation.
Defects in the RPS19 gene, encoding the ribosomal protein (RP) S19, are the main known cause of DBA and account for more than 25% of patients. Mutations in other RPs (RPS24, RPS17, RPL35a) have been reported in a minority of patients (Gazda et al., 2006; Cmejla et al., 2007; Farrar et al., 2008) and show that DBA is a disorder of ribosome synthesis. Recently, Gadza et al. (2007) reported the involvement of two new genes (RPL5, RPL11) encoding for RPs of the large subunit in a considerable percentage of DBA patients without mutations in RPS19 or RPS24 (10% and 6,5%, respectively).
Here we present the results of RPL11 mutation screening in Italian DBA patients without RPS19 or RPS24 mutations. Preliminary data of RPL5 analysis are also reported.
The human RPL11 gene includes 6 exons and spans 4622 bp on chromosome 1. We identified 12 heterozygous mutations in 80 analyzed probands (15%), 10 of which were deletions of 1–47 nucleotides causing frameshift and a premature termination; another deletion (12nt) resulted in a loss of 4 aminoacids. One acceptor splice site defect (intron 5) was also detected. RPL11 mutations were spread in all exons except for exon 1.
The human RPL5 gene spans 9888 bp on chromosome 1, and includes 8 exons. We identified one heterozygous mutation in RPL5 in 14 analyzed patients (7%); it is a single nucleotide deletion in exon 5 causing frameshift and a premature termination.
None of these sequence changes were found on the NCBI SNP dalabase (http://www.ncbi.nlm.nih.gov/SNP/).
Our mutations are expected to alter the genetic information drastically and to cause haploinsufficency. Depletion of RPs compromises ribosome biogenesis and disturbs rRNA processing at different levels (Robledo et al. 2008).
Interestingly, all mutated patients (11/13) showed one or more somatic malformations; specifically, thumb anomalies and growth retardation were present in 7/11 (64%) and 6/11 (54%) patients, respectively. The erythrocyte adenosine deaminase activity was performed in 6/13 mutated patients; all of them showed an increased activity. The majority of RPL11 mutated patients were transfusion-dependent at last follow-up (58%,7/12); the RPL5 mutated patient was in clinical remission after steroid treatment. No one of the mutated patients has so far developed neoplasia.
Our data show that RPL11 mutations are more frequent than expected (Gazda et al. 2007). They seem to confer a relevant association with a malformation phenotype as compared to RPS19 mutations.
Induction of the Unfolded Protein Response but Normal Basal Granulopoiesis in Mice Expressing G192X ELA2
Authors: Murakami Mark , Woloszynek Jill , Xia Jun , Liu Fulu , Link Daniel 
Published: April 2020

Abstract
Severe congenital neutropenia (SCN) is an inborn disorder of granulopoiesis characterized by chronic neutropenia, a block in granulocytic differentiation at the promyelocyte/myelocyte stage, and a marked propensity to develop acute myeloid leukemia. Most cases of SCN are associated with germline heterozygous mutations of ELA2, encoding neutrophil elastase (NE). To date, 59 different, mostly missense, mutations of ELA2 have been reported. A unifying mechanism by which all of the different ELA2 mutants disrupt granulopoiesis is lacking. We and others previously proposed a model in which the ELA2 mutations result in NE protein misfolding, induction of the unfolded protein response (UPR), and ultimately apoptosis of granulocytic precursors. Testing this (and other) models has been limited by the rarity of SCN and difficulty in obtaining clinical samples for testing. Herein, we report the preliminary description of a novel transgenic mouse line that expresses G192X Ela2, reproducing the G193X ELA2 mutation found in some patients with SCN. The G192X mutation was introduced into the murine Ela2 locus by homologous recombination in embryonic stem cells. Heterozygous or homozygous G192 Ela2 “knock-in” mice were healthy with no apparent developmental defect. While expression of Ela2 mRNA was normal, no mature NE protein was detected in the neutrophils of homozygous G192X Ela2 mice. However, in granulocytic precursors (mainly promyelocytes/myelocytes) a small amount of heavily glycosylated mutant NE protein was detected. Together, these observations suggest that G192X NE protein is retained in the endoplasmic reticulum (ER) and rapidly degraded. Consistent with ER stress and induction of the UPR, a significant increase in BiP/GRP78 and ATF6 mRNA expression in mutant granulocytic precursors were observed. Surprisingly, G192X Ela2 mice have normal basal granulopoiesis. The number of circulating neutrophils, granulocytic differentiation in the bone marrow, and number and cytokine responsiveness of myeloid progenitors were comparable to wild type mice. In summary, the G192X Ela2 mice appear to reproduce the NE protein misfolding and UPR activation observed in human SCN granulocytic precursors. However, expression of G192X Ela2 is not sufficient to disrupt basal granulopoiesis in mice. Studies of stress granulopoiesis are underway.
Disruption of a Functional Relationship Between PU.1 and Mir-155 during the Pathogenesis of Chronic Lymphocytic Leukemia (CLL)
Authors: Stopka Tomas , Vargova Karin , Berkova Adela , Kokavec Juraj , Trneny Marek , Zavadil Jiri 
Published: April 2020

Abstract
Role of small non-coding microRNAs (miR) in hematopoiesis has been recently established by work demonstrating critical importance of miR-223 for granulocytic development (Johnnidis 2008) and miR-155 in lymphocytic differentiation (Thai 2007) in mice. The importance of miR-155 is further supported by several independent studies demonstrating its increased levels in human diffuse large B-cell lymphoma (Eis 2005, Kluvier 2005, Volinia 2006, Lawrie 2007, Rai 2008) and in chronic lymphocytic leukemia (CLL) (Fulci 2007, Marton 2008). PU.1 is ETS family transcription factor involved in myelo-lymphoid differentiation and is directly negatively regulated by miR-155 (Vigorito 2007). Studying primary CLL (N=27) and normal (N=13) peripheral blood mononuclear cells, we found significantly increased miR-155 levels and also demonstrate that PU.1 levels are significantly decreased. Next, we have tested genes that are targets of both miR-155 and PU.1 including CSF1R and FOS and again demonstrated their significantly decreased expression in CLL. Using gene expression profiling of CLL peripheral lymphocyte samples compared to normal controls, we have determined significant downregulation of the PU.1 mRNA and of numerous miR-155 targets previously reported to be required for myelo-lymphoid differentiation. These findings suggest that the relationship between PU.1 and miR-155 becomes disrupted in CLL. This in turn leads to overexpression of miR-155, reduced levels of PU.1 and of numerous miR-155 targets (N=2481 and N=400 respectively) and to inhibition of PU.1 regulated differentiation and proliferation programs. Next, we correlated negative cytogenetic prognostic features (p53 and ATM gene deletion detected by FISH) of the CLL patients with the miR-155 and PU.1 levels, In a relatively small-size patient cohort studied so far, the low ratios of PU.1/miR- 155 levels are similarly distributed among low, intermediate and high risk CLL patients, suggesting that inverse correlation of PU.1 and miR-155 represents a hallmark of CLL and likely represents a primary event during CLL pathogenesis.
Disruption of CTNNB1/LEF-1 Complex by Small Molecule Inhibitors Induces Apoptosis in B-CLL Cells in Vitro and in Vivo
Authors: Gandhirajan Rajesh Kumar , Gehrke Iris , Paesler Julian , Razavi Regina , Filipovich Alexandra , Erdfelder Felix , Hertweck Magdalena , Plickert Guenter , Schmitt Esther Katharina , Schlösser Axel , Hallek Michael , Kreuzer Karl Anton 
Published: April 2020

Abstract
Deregulated WNT signaling has been implicated in variety of tumors. Previous findings suggest critical components of WNT signaling pathway (WNTs, FZD and LEF-1) are overepxressed in B-cell chronic lymphocytic leukemia (CLL) at the m-RNA level. β-catenin (CTNNB1)/LEF-1 transcription activation complex is the key component of WNT signaling which governs the expression of WNT target genes. Critical genes like C-MYC, survivin (SURV), cyclin D1 (CCND1) and LEF-1 which are also overexpressed in CLL are downstream targets of this pathway. In the current study we attempted to inhibit CTNNB1/LEF-1 interaction in CLL cells using the novel small molecule inhibitors CGP049090 and PKF115-584 and observed the survival potential both in vivo and in vitro. Substantial overexpression of LEF-1 and dephospho-CTNNB1, in CLL cells was observed when compared to healthy CD19 positive B cells and PBMCs suggests activation of WNT signaling in CLL. The LC50 calculated from 30 CLL patients was 1.18 μM for CGP049090 and 1.10 μM for PKF115-584 by the ATP based assay. This was confirmed by the DiSC assay LC50 of 0.33 μM (CGP049090) and 0.23 μM (PKF115-584) for primary B-CLL cells (n=3). Both substances showed little effects on normal PBMCs (n=5) as seen from the LC50 values of 90.92 μM and 39.88 μM for CGP049090 and PKF115-584, respectively. Time course experiments indicate activation of caspase 8, 9, 3 & 7, PARP cleavage and paralleled by downregulation of known inhibitors of apoptosis (IAPs) MCL-1, XIAP and BCL-2 leading to apoptosis. Co-immune precipitation of CTNNB1/LEF-1 complex was inhibited in the presence of CGP049090 and PKF115-584 suggesting the specificity of the interaction. Cellular uptake of PKF115-584 and cytoplasmic co-localisation with lef-1 was observed by fluorescence microscopy. In vivo studies reveal that both substances are highly tolerable and effective in eradicating tumor growth in xenografts. The tumor inhibitory rate (IRmax) was found to be 78% and 63.8% for CGP049090 and PKF115-584, respectively. These results indicate that LEF-1 is a promising target for B-CLL therapy as CGP049090 and PKF115-584 effectively induce apoptosis within micromolar concentrations in CLL cells but do not affect healthy cells at these doses. Downregulation of WNT target genes and IAPs hasten the apoptotic mechanism. Moreover, and these inhibitors are highly effective and tolerable in vivo which identifies both compounds as promising drugs for targeted therapy in CLL.
Erythrocyte Scaffolding Protein p55 Functions as An Essential Regulator of Neutrophil Polarity
Authors: Quinn Brendan J. , Chishti Athar H. 
Published: April 2020

Abstract
Erythrocyte p55 is a prototypical member of a family of scaffolding proteins known as Membrane Associated Guanylate Kinase Homologues (MAGUKs). MAGUKs are multi-domain proteins that couple signals from specialized sites at the plasma membrane to intracellular signal transduction pathways and the cytoskeleton. P55 was originally identified in the erythrocytes as part of a ternary complex with protein 4.1R and glycophorin C, providing a critical linkage between the actin cytoskeleton and the plasma membrane. Although p55 is expressed in a variety of tissues, especially hematopoietic cells, its biological function is unclear. Here, using a p55 knockout mouse model, we show that p55 plays a prominent role in the regulation of neutrophil polarization. Neutrophils are the first respondents during infection and injury, adopting a highly polarized morphology when stimulated with chemotactic factors. G proteincoupled surface receptors recognize the external chemotactic gradient and translate it into an internal gradient of signaling molecules. At the front of the cell, accumulation of the lipid product phosphatidylinositol-3,4,5-trisphosphate (PIP3), activation of the small GTPase Rac, and polymerization of F-actin stimulates a positive feedback loop promoting pseudopod formation. Here, we show that neutrophils lacking p55 form multiple transient pseudopods at the sides and back of the cell upon stimulation. P55 is required for limiting the pseudopod in the direction of chemoattractant. As a result, these neutrophils do not migrate efficiently up a chemotactic gradient in vitro. Biochemical analysis indicates that total F-actin polymerization and total Rac activation is similar between wild type and p55 knockout neutrophils. However, we found that phosphorylation of AKT, the major kinase downstream of the phosphatidylinositol 3-kinase (PI3K)-PIP3 pathway, is almost completely blocked in p55 knockout neutrophils. This finding suggests that p55 exerts its functional effect by regulating PIP3 accumulation or its localization at the membrane, which is responsible for amplification of the frontness signal and stability of the leading edge pseudopod. Consistent with this finding, the p55 null mice are significantly more susceptible to spontaneous and induced infections. Taken together, we have identified p55 as a novel mediator of the frontness signal in neutrophils that promotes polarization and efficient chemotaxis.