bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Roline Rich Domain of an RNA-Binding Protein Sam68 in B Lymphocyte Leukemia Cell Line Growth Process, Death and B Cell Signal Transduction.
Authors: Pang Tianxiang , Li Qinghua , Wang Jianxiang , Yuan Wensu , Zhang Lei , Han Zhongchao 
Published: April 2020

Abstract
Sam68 plays an important role as a multiple functional RNA binding nuclear protein in cell cycle progress, RNA usage, signal transduction regulation of cell growth and proliferation, and tyrosine phosphorylation by Src during mitosis. However, its precise impact on these essential cellular functions remains unclear. The purpose of this study is to further elucidate Sam68 functions in B lymphocyte leukemia DT40 cell line. By using gene targeting method, we isolated a mutation of deleted proline rich domain from Sam68 in DT40 cells and described its effect on cell growth process and signal transduction. The results have demonstrated that mutant cells grew at a slower rate (2.1 hours growth elongation). Cell cycle pattern was observed in mutant cells by flow-cytometric analysis, the retardation of cell growth was mainly due to the elongation of S phase (1.7 hours elongation). When the cell cycle was analyzed at different serum concentration conditions, we found that the effect of Sam68 mutant on the S phase was further supported by the serum depletion experiment. In light of evidence that RNA binding activity is essential for functions, Sam68 is implicated in cell growth control probably by modulating the function of mRNAs in S phase or earlier. Larger amounts of dead cells was observed in the culture of mutant cells, and serum depletion enhanced the ratio of dead cells in both culture conditions. Since the putative control of cell cycle by Sam68 appeared to be related to signal transduction, we next assessed the involvement of Sam68 in B cell signal transduction pathway. After cross-linking of B cell receptor on the DT40 cells by IgM antibody, phosphorylation of cellular proteins was analyzed by protein blotting with anti-phosphotyrosine antibody. The result demonstrated that the overall pattern of B cell receptor in Sam68 mutant cells was similar to that in the wild type DT40 cells. However, the maximal level of tyrosine phosphorylation on BLNK, a prominent signal molecule in B cell, has been observed no significantly changes in the mutant cells. Since the expression levels of B cell receptor on the Sam68 mutation clones were essentially same as that of parental DT40 cells, it was suggested that deletion of partial of proline region in Sam68 resulted in the decrease in B cell signal transduction. We have concluded that the proline rich domain of Sam68 is involved in cell growth control by modulating the function of mRNAs in S phase or earlier and the functions as an adaptor molecule in B cell signal transduction pathways.
Syndrome of Inappropriate Secretion of Anti-Diuretic Hormone in Children with Acute Lymphoblastic Leukemia.
Authors: Borker Anupama S. , Hutchins Sabrina , Grant Robin , Hijiya Nobuko , Sandlund John T. , Metzger Monika L. , Jeha Sima , Razzouk Bassem I. , Ribeiro Raul C. , Rubnitz Jeffrey E. , Hudson Melissa M. , Relling Mary V. , Pui Ching-Hon , Howard Scott 
Published: April 2020

Abstract
Background: The syndrome of inappropriate secretion of anti diuretic hormone (SIADH) is a well known complication of vincristine. Available literature on SIADH in pediatric acute lymphoblastic leukemia (ALL) focuses on patients with severe manifestations. We performed this study to determine the clinical consequences of SIADH that occurred during ALL therapy.
Patients and Methods: We studied all episodes of hyponatremia in patients with ALL diagnosed from December 1991 to October 2002 at St Jude Children’s Research Hospital who had not relapsed or undergone stem cell transplantation. SIADH was defined as sodium ≤ 130 meq/L in a euvolemic patient with increased urinary sodium excretion, decreased serum osmolarity and increased urine osmolarity with creatinine normal for sex and age. For each episode, we reviewed demographic features, treatment phase, predisposing factors, presenting features, duration, severity, treatment and outcome.
Results: Of 605 patients studied, 68 patients had 79 episodes of SIADH. Fifty-nine patients (87%) had only 1 episode while 9 patients (13%) had recurrences. The mean lowest serum sodium was 128.3 mEq/L (range, 121–130 mEq/L) and the mean duration of hyponatremia was 1.9 days (range, 1–14 days). Ninety-six percent of episodes were associated with the administration of 1 (n=29) or 2 (n=43) doses of vincristine in the preceding 2 weeks. Episodes were associated with infection in 51 cases and central nervous system pathology in 3 cases. Only 6 (8 %) patients had serum sodium 125 mEq/L or lower; 50% of these had altered mental status, compared to 7% whose sodium never fell below 125 mEq/L. Treatment included fluid restriction (46%), change or cessation of intravenous fluids (6%), diuretics (2%), or observation (46%). All symptomatic patients had complete neurological recovery.
Conclusions: SIADH is common during treatment for ALL but is rarely severe or symptomatic. The risk is greatest within 14 days of vincristine administration. Most episodes are self limited and need neither extensive investigation nor aggressive therapy.
Impact of mTOR Inhibition on FoxP3+ Regulatory T Cells as Compared to Conventional T Cells after Allogeneic Bone Marrow Transplantation.
Authors: Zeiser Robert , Leveson-Gower Dennis B. , Zambricki Elizabeth A. , Hou Jing-Zhou , Negrin Robert 
Published: April 2020

Abstract
FoxP3+CD4+CD25+ regulatory T-cells (Treg) have been shown to effectively reduce the severity of experimental acute graft-versus-host disease (aGvHD) while sparing graft-versus-leukemia activity. These findings, in concert with the observation that human and murine Treg share functional characteristics, have fueled interest in clinical trials to control aGvHD. Recent data indicates that the immunosuppressant rapamycin (RAPA) in contrast to cyclosporine A does not interfere with in vivo function of Treg and could enhance Treg expansion in vitro by a yet unknown mechanism.
To investigate the impact of mTOR inhibition on proliferating Treg and Tconv, both cell types were exposed to CD3/CD28 Mabs in the presence of different RAPA concentrations in vitro. Phosphorylation of mTOR downstream products p70S6K1 and 4E-BP1 were assessed by western blot and flow cytometry. Inhibition of the phosphorylation of p70S6K1 and 4E-BP1 was observed in both populations in the presence of RAPA. Interestingly, Treg were more resistant to mTOR inhibition as compared to Tconv and displayed significantly higher phosphorylated products in the presence of RAPA at 10 nM (MFI Treg vs Tconv, p&lt;0.001) and at 100nM (MFI Treg vs Tconv, p&lt;0.001).
To investigate whether Treg and RAPA protect from aGvHD in a synergistic manner, BALB/c recipients were transplanted with H-2 disparate BM and 1.6x10e6 T-cells (FVB/N) after lethal irradiation (8 Gy). aGvHD lethality was only slightly reduced when suboptimal Tconv:Treg ratios were employed (4:1, 8:1), or when recipients were treated with a non-protective RAPA dose (0.5 mg/kg bodyweight). Combining a suboptimal Tconv:Treg ratio with a non-protective RAPA dose reduced expansion of luciferase expressing (luc+) Tconv and pro-inflamatory cytokines and improved survival indicative for an additive in vivo effect of RAPA and Treg.
To evaluate the impact of RAPA on in vivo T cell expansion, either luc+ Tconv or luc+ Treg were adoptively transferred. In vivo bioluminescence imaging demonstrated that RAPA had a more potent inhibitory effect on proliferation of Tconv as compared to Treg (p&lt;0.05 vs. NS). We did not observe RAPA to increase FoxP3+ Treg numbers in vivo, or to enhance GITR or CTLA-4 expression.
Thus, increased Treg numbers observed in RAPA containing expansion cultures are likely due to a lower susceptibility of this cell population to mTOR inhibition. This could explain the observed synergistic effect of RAPA and Treg in aGvHD protection which has relevance for clinical trials utilizing Treg to prevent aGvHD.
Proteinase-Activated Receptor 1 Expression in Human Leukemia HL-60 Cells and Its Significance.
Authors: Xie Wan-Zhuo , Lin Mao-Fang , Huang He , Cai Zhen 
Published: April 2020

Abstract
The coagulation system is regularly activated in patients with acute leukemia, especially with acute promyelocytic leukemia. Up to 30% of these patients suffer from thromboembolic complications. Obviously, activation of thrombin occurs in the natural course of cancer. During tumor progression, many patients develop coagulation disorders; treatment is complicated by increased resistance of tumor cells to chemotherapy. Thrombin-mediated activation of cellular receptor(s), such as proteinase-activated receptor-1(PAR-1), plays an important role in tumor growth, local progression, and distant metastasis. Our hypothesis is, that leukemia cells that express PAR-1 have a survival benefit if they are activated by thrombin.We harvested HL-60 cells in vitro. We detected PAR-1 expression using reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence activated cell sorting (FACS) scan.We found that HL-60 cells expressed PAR-1 receptor. Furthermore,we employed a series of different concentrations of thrombin into the HL-60 cell culture system.With certain interval of low level of thrombin, HL-60 cell growth was enhanced,in contrast, we found that HL-60 cell apoptosis was observed under higher concentration of thrombin.In summary, we found that human leukemia HL-60 cell exhibits a positive PAR-1 expression. Also, thrombin could influence the growth of HL-60 mediated by PAR-1 possibly. Further experiments will show if these cell-biological mechanisms aggravate cellular proliferation/apoptosis in leukemia cells. Therapeutic consequences, such as therapeutic thrombin inhibition in addition to chemotherapy are discussed.
CD44-Ligation Triggers IL-1, GM-CSF and IL-8 Driven Differentiation Pathways in Human Monoblastic Leukemia Cells.
Authors: Smadja-Joffe Florence , Delaunay Jacques , Qi Junyuan , Gadhoum Zeineb , Ingeneer Laetitia Durand , Chomienne Christine 
Published: April 2020

Abstract
The CD44 surface antigen is highly expressed on AML cells. We previously reported that its ligation with specific monoclonal antibodies (mAbs) triggers terminal differentiation of leukemic blasts in all AML subtypes. This raised the perspective of developing a CD44-targeted therapy that would be efficient in all AML subtypes, including the monoblastic one (AML-M5) in which, in the absence of specific genetic abnormalities, no targeted therapy is being developed. Here we investigated the molecular mechanism responsible for the CD44-induced differentiation in primary AML-M5 blast samples (n=13). Firstly, by using cDNA arrays, we show that CD44 ligation:activates a burst of cytokine and chemokine genes, through the p38MAPK pathway, indicating that normal CD44 pathways are functional in AML-M5 blasts; andmodulates the gene expression of enzymes, surface proteins and transcription factors as in normal monopoiesis.Secondly, by using functional inhibitors, we demonstrate that the differentiation of CD44-ligated AML-M5 blasts is mediated by IL-1b, GM-CSF and IL-8. These proteins act locally, through an autocrine/paracrine pathway, suggesting that most of the drawbacks often provoked by their systemic injection should be very attenuated. Together, these results provide new support for the development of a CD44-targeted differentiation therapy in acute monoblastic leukemia.
Clinical Significance of Free Circulating CD34 in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome.
Authors: Hodge Menna , Giles Francis , Abdool Adam , O’Brien Susan , Keating Michael , Jilani Iman , Estrov Zeev , Estey Elihu , Kantarjian Hagop , Albitar Maher 
Published: April 2020

Abstract
CD34 is an approximately 116-kd glycophosphoprotein expressed in hematopoietic progenitor cells, endothelial cells, and some mesenchymal and neural cells. CD34 is a typical adhesion molecule capable of inducing the cell signal transduction pathway leading to adhesion and differentiation. We used a newly developed bead-based assay to measure cell-free circulating CD34 (cCD34) in the plasma of patients with acute myeloid leukemia (AML; n = 98) and myelodysplastic syndrome (MDS; n = 50). Levels of cCD34 were significantly higher in AML (median 10983, range: 844–100,4191 U/10 μl than in MDS (median: 8749, range:102–791,350 U/10 μl) patients (P&lt;0.01). cCD34 levels were higher among patients with high-risk cytogenetic abnormalities in AML (P = 0.01) but not MDS (P = 0.92). When grouped together, AML and MDS patients with cCD34 levels higher than the median (10,845 U/μl) had significantly shorter survival than those with lower levels (P = 0.01). This association was independent of cytogenetic grouping, age, and performance status. cCD34 levels did not correlate with percent of blasts or CD34+ cells but did correlate with WBC count (R = 0.36) in patients with AML, suggesting that cCD34 reflects the overall leukemia load. Although further study is needed for confirmation, cCD34 appears to result from turnover of leukemic cells and may affect the activation of certain pathways, therefore influencing survival and clinical outcome.
Figure Figure
Stromal Cell Line Enhances Survival of Myeloid Leukemia Cells by Regulating the Expression of bcl-2 Family Genes and Caspase-3.
Authors: Xu Zhenshu , Liu Yongjun , Han Zhibo , Lv Lulu , Yang Ting , He Rui , Chen Zhizhe , Han Zhongchao 
Published: April 2020

Abstract
Approximately 20–30% acute myeloid leukemia (AML) patients are not cured by traditional chemotherapy. The possible explanation is that residual leukemia cells are harbored in association with stromal cells in the bone marrow, which causes late relapse of leukemia. This study was designed to investigate interactions between marrow stromal microenvironment and leukemia cells. AML cells were cultured in different conditions with or without serum, Ara-c, the monolayers or the conditioned medium of a stromal cell line HESS-5. Apoptosis frequencies, cell viability, cell cycle distribution, DNA fragment, and bcl-2/bcl-xl gene as well as caspase-3 expression were determined by Typan blue exclusion, MTT assay, flow cytometry analysis, PCR and Western blot respectively. Direct contact of HL-60 cells with HESS-5 significantly inhibited serum-deprivation- or Ara-c-induced apoptosis of HL-60 cells, and resulted in a significant increase of short-term proliferation and viability. Soluble factors had negligible effect. The interaction of HL-60 with fibronectin did not confer a significant resistance to serum-deprivation and Ara-c agent. HESS-5 cells were also able to maintain cell cycle progression of HL-60 during chemotherapy exposure. HESS-5 cells-mediated apoptosis inhibition was associated with increased bcl-2/bcl-xl expression and down-regulation of caspase-3 in primary myeloid leukemia cells. These results indicate that stromal cells enhance the survival of myeloid leukemia cells by regulating bcl-2 family genes as well as caspase-3 protein and suggest that specific interactions between stromal cells and leukemia cells may enhance the resistance of leukemia cells to chemotherapy.
Analysis of NPM1 Gene Mutations in Chinese Adults with Acute Myeloid Leukemia.
Authors: Wu De Pei , Yan Lingzhi , Chen Suning , Liang Jianying , Feng Yufeng 
Published: April 2020

Abstract
Many European groups have described that mutations at exon-12 of the nucleophosmin (NPM1) gene are the most frequent genetic lesion in acute myeloid leukemia (AML) (45.7%~61.7% of all adult AMLs with normal karyotype). This outstanding discovery provides a promising minimal residual disease (MRD) marker for AMLs with normal karyotype. To clarify the prevalence and the clinical profile of NPM1 mutations in Chinese patients with AML, we analyzed a cohort of 156 newly diagnosed adult AMLs for this mutation. Genomic DNAs were prepared from bone marrow samples of these patients. NPM1 exon 12 mutations were detected using direct sequencing or fragment analysis of DNA-PCR products. NPM1 mutations were present in 28.2% of the overall population, including 1/1(100%) of M0, 11/27(40.7%) of M1, 11/46(23.9%) of M2, 0/29(0%) of M3, 2/9(22.2%) of M4, 18/39(46.2%) of M5 and 1/5(20.0%) of M6. NPM1 gene mutations were more prevalent in patients with a normal karyotype (37 of 90; 41.1%), when compared with patients with karyotypic abnormalities (7 of 66; 10.6%; P&lt;0.001). Sequence analysis of 25 NPM1 mutated cases revealed known mutations (type A, B, NM, and PM) as well as 1 novel sequence variation (here named as type S). All mutational types were heterozygous and showed a 4 bp insertion between position nucleotide 960 and 961 (Genebank accession number: NM-002500). NPM1 mutations were significantly associated with old age (P&lt;0.05), high peripheral white cell count (P&lt;0.05) and FAB-M1/M5, but negatively associated with expression of CD34 (P&lt;0.05) and CD117 (P&lt;0.05). In conclusion, NPM1 mutations also represent a common genetic abnormality in Chinese adults with AML, especially in the presence of a normal karyotype. The occurrence of NPM1 mutations indicates an age-dependent characteristic. NPM1 mutated cases show a special clinical subtype of AML. Further studies are urgently needed to confirm the role of NPM1 mutations in leukemogenesis. The altered nucleo-cytoplasmic transport of NPM1 mutated protein is probably a potential therapic target for AML with NPM1 mutations.
Gain-of-Function WASP Mutations in Pediatric and Adult Patients with Myelodysplasia or AML.
Authors: Beel Karolien , Schollen Els , Uyttebroeck An , Verhoef Gregor , Demuynck Hilde , Devriendt Koen , Vandenberghe Peter 
Published: April 2020

Abstract
X-linked neutropenia (XLN, OMIM #300299)) was first described in 2001 in a three-generation Belgian family with five affected members and with a L270P gain-of-function mutation in the GTPase binding domain (GBD) of the Wiskott-Aldrich-syndrome protein (WASP) (Nat Genet2001,27,313). Although all five L270P cases originally presented with neutropenia, two of them eventually developed a myeloid malignancy while under G-CSF, with monosomy 7 in the malignant cells. One male (II.3) developed a myelodysplastic syndrome (MDS-RAEB) at age 65, achieved stable remission after three courses of decitabine, but died three years later due to an unrelated cause. A second patient (III.6) succumbed to refractory MDS RAEB, rapidly evolving to MDS-RAEBt at age 38. Since our original report, two more cases with XLN have been reported, one with a I294T and one with a S272P WASP mutation. (Ancliff et al. Blood online 2006). The I294T case, 4 years old, had myelodysplastic features at presentation. These observations have prompted us to investigate whether inherited gain-of-function WASP mutations are associated with paediatric MDS or AML. In addition we have explored whether acquired WASP mutations occur in adult myeloid malignancies. 207 cases were examined. Male/female ratio was 1.35. 34 cases were between 2 months and 20 years old and 173 cases were between 21 and 89 years old. There were 48 cases with myelodysplasia, 157 had acute myeloid leukaemia and 2 had myelofibrosis. 29% had monosomy 7. There were two brothers with monosomy 7, one with AML M5 and the other with secondary ALL after MDS. Exons 7-10, encoding the GTPase Binding Domain (residues 230-381), were amplified and screened for mutations using dHPLC. In these 207 samples from patients with MDS or AML, no mutations were found in the exons 7-9 of the WAS gene. One mutation was found in intron 6 in a male patient with AML and monosomy 7. The mutation did not influence splicing of the exon and was thus considered irrelevant. Four patients had a known T1029C (V332A) single nucleotide polymorphism in exon 10. One patient with AML (age 50y) had a C975T (P314S) mutation in exon 10, which has not been reported previously. Since this mutation occurs in less than 1%, it does not qualify as a polymorphism. If relevant for the pathogenesis of AML, the mutation is very rare whatsoever. Although the eventual risk of malignant myeloid transformation appears to be increased in L270P XLN, we could not, with one exception, identify mutations in exons 7-10 of the WAS gene in this series of paediatric and adult MDS/AML. Therefore, inherited or acquired WAS mutations do not seem to be commonly associated with pediatric or adult MDS or AML. Our data therefore do not support screening for exon 7-10 mutations of WAS in the context of paediatric or adult MDS and AML.
Co-Operativity between Antibody-Dependent Cellular Cytotoxicity (ADCC) and Immunotoxin-Mediated Killing of Human T-ALL Cells in a SCID Mouse Model: Simultaneous Delivery of Saporin Via CD7 and ADCC Via CD38 Is No Better Than the Simultaneous Delivery of Each Against Only CD7.
Authors: Flavell David J. , Flavell Sopsamorn U. 
Published: April 2020

Abstract
We have previously shown that the anti-CD7 saporin-based immunotoxin (IT) HB2-SAPORIN and host antibody-dependent cellular cytotoxicity (ADCC) co-operate in the killing of human T-ALL a SCID mouse model of this disease (Flavell et al 1998 Cancer Res 58, 5787). In this described model system it is the same anti-CD7 IT that is responsible for delivering both the ribosome inactivating protein saporin and eliciting ADCC by recruiting NK cells via binding of their FcγRIIIA to the Fc domain of target cell bound IT. There is however a conflict here in that for the IT to be effective it needs to internalize whilst for maximally effective ADCC, the IT needs to remain on the cell surface in order to recruit cytotoxic effector cells. Over 90% of HB2-SAPORIN IT is internalized by CD7+ HSB-2 target cells within 12h following bivalent ligation by this IT and yet the ten percent or less of CD7 remaining on the target cell surface appears sufficient to elicit adequate ADCC to achieve the co-operative effect in vivo. The question is if ADCC is performing sub-optimally due to the reduced amount of target cell expressed CD7 doe this mean that the subsequent co-operative effect is also sub-optimal and could this be improved upon to achieve a greater and more effective target cell kill?
To attempt to answer this question we have targeted saporin to the HSB-2 target cell via CD7 using a F(ab)2 IT (HB2-F(ab)2−-SAPORIN) that is incapable of eliciting ADCC whilst simultaneously delivering ADCC via an intact IgG1 anti-CD38 antibody (OKT10) that also binds to the target cell surface. The expression level of CD38 on HSB-2 cells is approximately ten-fold higher than CD7 and importantly the observed CD38 internalization rate and extent is considerably reduced compared with CD7 when ligated by cognate antibody. We therefore predicted that increased ADCC would be deliverable to HSB-2 target cells with OKT10 antibody and an in vitro chromium release assay confirmed this. However, the in vivo treatment of SCID-HSB-2 mice with a combination of HB2-F(ab)2-SAPORIN and intact OKT10 antibody was not significantly better than treatment with HB2-SAPORIN intact IT alone. These preliminary data indicate that even though additional ADCC is apparently deliverable with the OKT10 antibody this does not result in a further enhancement of the co-operative effect in vivo suggesting that the optimum co-operativity threshold has already been reached in the HB2-SAPORIN mono-therapy system.