bluuebunny/crossref_metadata_2025_split huggingface dataset:
RAX Activates Tumor Suppressor p53.
Authors: Pan Yu , Bennett Richard L. , May W. Stratford 
Published: October 2019

Abstract
Recently, our laboratory identified RAX as a unique cellular activator for the interferon-induced double-stranded RNA-dependent protein kinase, PKR. Cellular stresses such as IL-3 withdrawal from factor dependent hematopoietic cells, inflammatory cytokine and chemotherapy treatment or viral infection promote RAX phosphorylation with activation of PKR leading to inhibition of new protein synthesis. In addition, PKR can also regulate the transcription factors p53, STAT1 and NF-kB. Now we report a novel activity for RAX in regulating the expression and activity of the tumor suppressor, p53. Results indicate that increased RAX expression in p53 expressing cells, such as HEK293, mouse embryo fibroblast (MEF) or human osteosarcoma U2OS promotes an increase in the steady-state level of endogenous p53 and its activation of the p53 target gene, p21. Furthermore, when RAX is expressed in U2OS cells or coexpressed with p53 in p53 null H1299 cells, enhanced, dose-dependent p53 transcriptional activity is observed as assessed using a p53 luciferase reporter. Consistent with these findings, flow cytometry demonstrates that either RAX or PKR can stimulate p53-dependent G1 arrest that precedes apoptosis. Since p53 is a major ‘sensor’ for DNA damage leading to cell cycle arrest and apoptosis, we also examined whether RAX enhances p53’s response to DNA damage. Following gamma irradiation or Cisplatin treatment of p53 expressing cells, expression of exogenous RAX augments while ‘knock down’ of endogenous RAX by siRNA or expression of the dominant-negative, RAX (S18A) mutant, potently blocks any increase in p53 and p21 expression compared to vector-only control cells. While we find no evidence that RAX directly interacts with p53, results indicate that RAX promotes p53 SUMOylation but does not affect p53 ubiquitination or interaction with MDM2. We now propose that RAX augments the p53 stress-dependent cellular response potentially by a PKR-dependent mechanism involving SUMOylation. Since p53 is only mutated in apparently 15% of hematologic malignancies versus more than 50% in solid tumors, it is envisioned that a more detailed understanding of the mechanism by which RAX activates p53 may serve as a basis for novel antileukemic strategies.
Outcome of Infants Less Than One Year of Age with Acute Lymphoblastic Leukemia Treated with the Interfant-99 Protocol.
Authors: Pieters Rob , Schrappe M. , de Lorenzo P. , Hann I. , Vora A. , deRossi G. , Biondi A. , Felice M. , Hovi L. , Mechinaud F. , Szczepanski T. , Ferster A. , Janka G. , Rubnitz J. , Silverman L. , Stary J. , Campbell M. , Mann G. , Suppiah R. , Valsecchi M. 
Published: October 2019

Abstract
Introduction
Acute lymphoblastic leukemia (ALL) in infants under 1 year of age is rare and has a poor outcome compared to ALL in older children. It is characterized by a high expression of MLL gene rearrangements, high tumor load and myeloid features. In 1999, a large collaborative international study, Interfant-99, was initiated with the aims to determine: (1) the outcome of a new treatment protocol including ALL and AML elements; (2) in a randomised way the value of a late intensification course with high dose araC and methotrexate; (3) which clinical and biological factors have independent prognostic value within infant ALL. Event-free survival (EFS) and overall survival (OS) were primary endpoints and analysed on an intention to treat basis.
Results
17 study groups representing >20 countries enrolled 482 patients leading to by far the largest trial ever reported in infant ALL. 79% of cases had an MLL rearrangement. Of these, 53% was t(4;11), 20% t(11;19), 11% t(9;11) and 16% had other MLL partner fusion genes.
Death in induction rate was 3.8% and 2.3% did not achieve CR at the end of induction, so CR rate was 94%. Death rate in CCR was 5.2%. Relapses occurred in 36% of cases and were mainly isolated bone marrow relapse. Median time from 1st CR to relapse was 8 months. The overall 4-year EFS is 47% and OS is 55%. This is at least comparable to the best historical controls and better than most of those of the participating study groups. Especially outcome of high-risk patients, defined by poor response to one week prednisone, had improved. The late intensification course with HD-araC and HD-MTX did not improve outcome.
Cox model showed that MLL rearrangement and age <6 months were strong independent prognostic factors for poor outcome. WBC > 300x10e9/L and poor prednisone response were also of independent prognostic value. The outcome was not depending on the type of MLL rearrangement.
Conclusions
Results of this first international treatment protocol for infant ALL are very satisfactory. Early bone marrow relapse remains the major cause of treatment failure indicating that early treatment intensification is necessary. The large international collaboration has enabled the start of studies to improve outcome for infant ALL. The new Interfant-06 study will stratify the patients based upon MLL status, age and WBC and will study the value of the use of two early "AML" courses in a randomised way.
Mutations of the Catalytic Subunit of Class IA PI3K Are Constitutively Active and Confer Factor-Independent Growth to Early Hematopoietic Cells.
Authors: Horn Stefan , McCubrey James , Stocking Carol , Truemper Lorenz , Basecke Jorg 
Published: October 2019

Abstract
Background: Activating mutations of the catalytic subunit of class IA phosphoinositide 3-kinase alpha (PIK3CA) are clustered in small hot-spot regions of the PIK3CA gene, including exon 9 within the helical domain and exon 11 within the kinase domain. They have been linked to several human neoplasias, including colorectal, breast and hepatocellular cancers. In acute leukemias, PIK3CA mutations have not been investigated in larger chorts and so far only been observed in a few patients. Since the PI3K/Akt/GSK3beta pathway is an important signaling cascade of receptor tyrosine kinases (e.g. Flt3R, Kit) which are frequently activated in acute leukemias we investigated the functional activity of PIK3CA mutants.
Materials and methods: We transfected early hematopoietic cells (Ba/F3 cell line) with PI3KCA exon 9 and 11 mutations and investigated the cells in an in vitro factor-independent growth assay and pharmacologic inhibition experiments.
Results: We demonstrate that mutations in the helical or kinase domain of PIK3CA lead to the constitutive activation of PI3Kalpha in Ba/F3 cells, inducing factor-independent growth of the IL3-dependent cells. The frequency of IL3-independent Ba/F3 cells after tranfection with exon 9 and 11 PIK3CA mutants was equivalent to the frequency confered by PIK3CA mutants containing the membrane localization signal of either src or ras. Proliferation and survival of the cells were inhibited by the PI3K inhibitors LY294002 and Quercitin or an inhibitor of the PI3K downstream target Akt. Inhibition occurred in a dose- and time-dependent manner and could be reverted by addition of IL-3. One of the major targets of PI3K/Akt signaling is GSK3beta which becomes inactivated after Akt-mediated phosphorylation. By using a GSK3beta-specific inhibitor or LiCl we could show that the inactivation of GSK3beta alone did not result in factor-independent growth of Ba/F3 cells. However, GSK3beta inhibition led to a delay in the induction of cell death after IL3-withdrawal.
Conclusion: Activating mutations of PIK3CA, associated with several human neoplasias and acute leukemia are functionally active in hematopoietic cells, confer factor independency and respond to PI3K/Akt inhibition.
Dominant-Negative Effect of NPM-RAR on NPM Mediated Regulation of p53.
Authors: Redner Robert L. , Swaney Erin M. , Rush Elizabeth A. 
Published: October 2019

Abstract
We have been studying the variant Acute Promyelocytic Leukemia (APL) translocations with a view towards identifying common molecular pathways underlying APL. The t(5;17) variant of APL fuses the N-terminal 117 amino acids of nucleophosmin (NPM) with the C-terminal 402 amino acids of the retinoic acid receptor alpha (RAR). NPM plays a role in several important pathways within cells beyond its originally described function in the transport of ribonucleoproteins. It serves a chaperone function in transport of proteins such as p53, Tat, Rb, YY1, IRF-1, and Arf. NPM binds to and becomes a target of CDK2/cyclin E to play a role in regulation of centrosomal duplication. The importance of NPM in myeloid leukemias has been highlighted by the recent finding that mutation of the NPM C-terminus is the most common genetic event in non-APL acute myeloid leukemia. We have previously shown that the RAR portion of NPM-RAR acts as a dominant-negative towards wild-type RAR. We now investigate the hypothesis that NPM-RAR serves as a dominant negative for NPM and partially contributes to the leukemic phenotype through disruption of NPM-dependent cellular functions. We have focused our studies on the effects of NPM-RAR on p53. It has previously been shown that NPM directly binds to p53 to increase p53 stability and p53-dependent transcription. The p53-interaction domain maps to a region of NPM that is not contained in NPM-RAR. We hypothesized that NPM-RAR might bind directly with NPM, disrupt NPM association with p53, and thereby indirectly affect p53 activity. We first used pull-down assays of Maltose Binding Protein (MBP)-NPM or MBP-NPM-RAR fusions incubated with 35S-NPM to determine that the N-terminal domain of NPM-RAR is sufficient to interact with NPM. To investigate whether NPM-RAR alters NPM interaction with p53, we transfected COS cells with expression vectors encoding NPM, p53 and either NPM-RAR or control plasmid (pBluescript). Complexes were precipitated with an anti-NPM antibody (that recognizes epitopes not contained in NPM-RAR) and immunoblotted with an anti-p53 antibody. We found a decrease in the p53 signal captured by NPM in the lysate expressing NPM-RAR, compared to the control lysate. To further investigate the effects of NPM-RAR on p53, we made use of a transcriptional assay utilizing a reporter gene under control of a p53 response element. We co-transfected COS cells with a mix containing NPM-RAR, p53, and NPM expression plasmids, along with a p53-luciferase reporter (containing a 20 base pair p53 response element derived from the p21 promoter), and a ß-gal transfection control plasmid, or a similar mix in which NPM-RAR was replaced by an equivalent amount of carrier DNA (pBluescript). We found that the co-expression of NPM-RAR led to a decrease in the luciferase activity. These results support our hypothesis that NPM-RAR binding to NPM interferes with NPM’s ability to regulate p53.
Human Platelet Tissue Factor Is Localized in Lipid Rafts and Is Associated with GPIb-IX-V Complex in the Membrane: Association between Adhesive and Procoagulant Activities of Platelets.
Authors: Panes Olga , Matus Valeria , Sáez Claudia G. , Gárate Alan , Pereira Jaime , Mezzano Diego 
Published: October 2019

Abstract
The binding of platelet membrane GPIb-IX-V to extracellular matrix proteins and von Willebrand factor initiates the adhesion, spreading and activation of platelets. On the other hand, tissue factor (TF) triggers the blood coagulation by binding FVII/VIIa. In resting platelets, TF is stored mainly as a non active (“encrypted”) form, possibly through a dimer- or heterodimer complex. The encryption seems not to affect the TF capacity to bind FVII and VIIa, in such form that the membrane-based complex would be “primed” to trigger the clot formation upon platelet activation. Accordingly, the platelet adhesion and activation would be tightly interwoven with thrombin generation. Given the described localization of GPIbα in platelet lipid rafts, which appears to modulate its activity, we investigated whether TF is also present in these cholesterol-rich domains of the platelet membrane. Continuous sucrose gradients generated by ultracentrifugation at 180.000g x 18h at 4°C were used to obtain cholesterol-rich fractions from platelet lysates (1% Triton X-100 at 4°C). Western blots of each gradient fraction using a polyclonal anti-TF antibody revealed a protein of ~60kDa only in the fractions rich in cholesterol (using flotillin-1 as a marker). TF-dependent procoagulant activity (PCA), assessed by FXa generation was measured in resting and 5μM TRAP-stimulated, leukocyte-free platelets. In both cases, PCA was reduced after membrane cholesterol depletion with methyl-β-cyclo-dextrin. We also found that PCA was significantly enhanced in washed platelets treated with VWF and ristocetin, suggesting some form of functional or structural relationship between GPIb-IX-V complex and TF. GPIb-IX was immunoprecipitated (IP) from human platelet membranes by anti-GPIbα MoAbs (AP-1 or SZ2), in both resting and stimulated platelets (TRAP or VWF-ristocetin). The IP product was revealed with MoAb anti-TF (American Diagnostica, clone 4509) or polyclonal anti-TF, detecting a protein of ~47kDa. When we used MoAb anti-TF for the IP and MoAb anti-GPIX (BL-H6, anti-CD42a) to reveal the western blot, two distinct bands of ~22 and ~47kDa were disclosed, probably corresponding to GPIX and a heterodimer of GPIX and TF, respectively. These observations indicate that, at least a fraction of the platelet TF is localized in lipid rafts and that TF is also in close association with the GPIb-IX-V complex. This co-localization probably has important functional implications as demonstrated by the defective thrombin generation in patients with Bernard-Soulier syndrome. Moreover, this functional association may be relevant in both normal hemostasis and thrombus formation and growth.
Role of Gender in the Clinical Presentation of a First Deep Venous Thrombosis (DVT) in Outpatients.
Authors: Andreou Roseann , Koru-Sengul Tulay , Linkins Lori-Ann , Bates Shannon M. , Ginsberg Jeffrey S. , Kearon Clive 
Published: October 2019

Abstract
BACKGROUND: As clinical assessment of pretest probability (PTP) is now considered the first step in the diagnostic evaluation of DVT it is important to know if the clinical features of DVT are the same in men and women.
OBJECTIVES: We sought to answer the following questions: 1) Is the prevalence of DVT the same in men and women who are referred for diagnostic testing? 2) Are the clinical features of DVT the same in men and women? 3) Does the Wells’ clinical prediction model for first DVT perform similarly in men and women?
METHODS: We performed a retrospective analysis of individual patient data from three studies that evaluated diagnostic testing in outpatients with a suspected first episode of DVT. Associations were assessed using univariable and multivariable analyses.
RESULTS: A total of 1838 patients were eligible for final analyses, of whom 1132 (62%) were women and 706 (38%) were men. DVT was objectively diagnosed in 208 patients (11%). QUESTION 1: The prevalence of DVT was higher in men (14%) than in women (9%) (p=0.001). In a multivariable analysis that included eleven other clinical variables male gender was independently associated with a higher prevalence of DVT (OR 1.5, 95% CI 1.1–2.1). QUESTION 2: Of the confirmed episodes of DVT, “swelling of the entire leg” was observed more often in women (41%) than in men (16%) (p<0.001). This difference was partly explained by more extensive thrombosis in women than in men; the common femoral vein was involved on ultrasound in 48% of women and 22% of men (p< 0.001). The frequency of other clinical features was similar in men and women. QUESTION 3: The prevalence of DVT was higher in men than in women who were categorized by the Wells model as having a low PTP (6.9% vs 3.6%; p=0.025) or a moderate PTP (16.9% vs. 8.7%; p<0.001), but similar in the high PTP category (40% vs 44%; p=0.6). Five clinical features were more strongly associated with presence of DVT in women than in men: “swelling of the entire leg” (OR 7.7 vs. 1.6; p<0.001), “difference in calf circumference >3cm” (OR 8.2 vs. 2.9; p<0.001), “pitting edema” (OR 4.4 vs. 1.8; p=0.004), “age > 60 yrs” (OR 1.8 vs. 0.9; p=0.02) and “bedridden for greater than 3 days” (OR 3.7 vs. 1.4; p=0.05).
CONCLUSIONS: Among outpatients referred with a suspected first episode of DVT, the prevalence of DVT is higher in men than in women but DVT is more extensive in women. Entire leg swelling is a more common and important sign of DVT in women than in men and the Wells prediction rule behaves differently in men than in women.
Risk Stratification by MLL Gene Status and Outcome of Acute Lymphoblastic Leukemia in Infants: A Report from the Japan Infant Leukemia Study Group.
Authors: Tomizawa Daisuke , Koh Katsuyoshi , Nagayama Jun , Sato Takashi , Kinukawa Naoko , Isoyama Keiichi , Kosaka Yoshiyuki , Oda Takanori , Oda Megumi , Hayashi Yasuhide , Horibe Keizo , Mizutani Shuki , Ishii Eiichi 
Published: October 2019

Abstract
Background: Acute lymphoblastic leukemia (ALL) in infants represent 2.5% to 5% of all childhood ALL, and has an inferior therapeutic outcome compared to that of older children. Among several risk factors, rearrangement in MLL gene is most closely associated with this poor outcome. This is the first series of cooperative group trials stratifying ALL in infants with MLL gene status.
Procedure: Infants with ALL, age less than 12 months, were registered on two consecutive multi-center trials designated MLL96 and MLL98. All the patients were tested for MLL gene rearrangements by Southern Blot analysis and/or fluorescence in situ hybridization. According to the MLL gene status, patients with rearranged MLL gene were allocated to intensive chemotherapy followed by hematopoietic stem cell transplantation (HSCT), and those with germline MLL were treated with standard chemotherapy alone (total treatment duration was 83–85 weeks). In MLL98 study, treatment intensification and early use of HSCT were introduced compared to MLL96 study.
Results: A total of 101 infants were enrolled between December 1995 and December 2002. Seventy-nine had rearranged MLL and 22 had germline MLL. Event-free survival (EFS) of all 101 infants with ALL was 52.0% at 5 years; 5-year EFS for MLL rearranged cases was 39.7%, and for MLL germline cases was 95.5% (p<0.001). Among the MLL rearranged patients, 3-year EFS improved from 34.0% in MLL96 trial (N=41) to 43.6% in MLL98 trial (N=38). Although their were no secondary malignancies among the whole enrolled patients, physical growth impairments was observed in MLL rearranged patients, while no significant late effects were observed in MLL germline patients.
Conclusions: Risk stratification with MLL gene status was successful for infants with ALL. Excellent results were obtained for the germline MLL group using chemotherapy alone, and early introduction of allogeneic HSCT in first remission seemed effective for the MLL rearranged group. However, use of HSCT with less toxic conditioning regimens or development of effective chemotherapy including molecular target therapy are needed for MLL rearranged patients in order to avoid severe late effects for infants.
Risk of Venous Thromboembolism Is Not Increased by Elevated TAFI Levels.
Authors: Folkeringa Nienke , Brouwer Jan Leendert P. , Veeger Nic J.G.M , van der Meer Jan 
Published: October 2019

Abstract
TAFI (Thrombin-activatable fibrinolysis inhibitor) is a suppressor of fibrinolysis and high plasma levels of TAFI are assumed to induce venous thromboembolism (VTE). A few studies published on this subject identified TAFI as a mild risk factor for VTE. The risk may be increased if high TAFI levels are combined with other trombophilic defects. We performed a retrospective study to asses the absolute risk of VTE associated with elevated levels of TAFI and the contribution of concomitant thrombophilic defects. Subjects were recruited from a previous large family cohort study, which was designed to estimate the risk of VTE in first degree relatives of probands with documented VTE and a hereditary deficiency of antithrombin, protein C or protein S. Probands were excluded from analysis. Blood samples of relatives were tested on deficiencies of antithrombin, protein C and protein S, prothrombin G20210A, factor FV Leiden, hyperhomocysteinemia and increased levels of factor VIII:C, IX:C and XI:C. TAFI activity was additional measured by chromogenic assay on plasma samples stored at minus 80 degrees Celsius.
We analysed 350 of 457 relatives, who were tested on TAFI. TAFI levels observed in women were lower than in men (median 97 versus 106 U/dL) and increased with age (median from 95 U/dL at age 15–30 yr to 107 U/dL at age>60 yr). Relatives with TAFI levels above the 90th percentile (>128 U/dL) had the same absolute risk of VTE as relatives with TAFI levels below the 90th percentile. Annual incidences (AI) were 0.74 versus 0.72 % per year: relative risk (RR) 1.0; 95% CI.0.51–2.10 (Table).
Concomitant thrombophilic defects were demonstrated in 82% of the relatives. These defects were equally distributed among relatives with TAFI levels of >90th versus <90th percentile. Relatives with TAFI levels above the 90th percentile and concomitance of at least one other thrombophilic defect were not at increased risk of VTE compared to relatives with lower TAFI levels and concomitant thrombophilic defects (RR 0.83; 95% CI 0.41–1.68).
Our data do not support that eleveated TAFI levels are a risk factor for VTE. The high absolute risk of VTE among relatives is mainly due to the presence of other thrombophilic defects rather than elevated TAFI levels, as interactions between TAFI and other thrombophilic defects were not demonstrated.
VTE (n) Observation years AI (95% CI) RR (95% CI) TAFI > 90th percentile 9 1209 0.74 (0.3–1.4) 1.0 (0.51–2.10) Concomitance 9 1147 0.78 (0.4–14.9) 0.83 (0.41–1.68) No concomitance 0 62 0 TAFI < 90th percentile 53 7364 0.72 (0.5–0.9) Ref Concomitance 53 5724 0.93 (0.7–1.2) Ref No concomitance 0 1426 0