bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Pro-Metastasis Tyrosine Phosphatase, PRL-3 (PTP4A3), Is a Novel Target of BCR-ABL Signaling Involved in Human Chronic Myeloid Leukemia
Authors: Zhou Jianbiao , Cheong Lip-Lee , Mahara Sylvia , Liu Shaw-Cheng , Chong Phyllis SY , Bi Chonglei , Koh Tze-Loong , Ong Kelly OK , Zeng Qi , Chng Wee-Joo 
Published: October 2019

Abstract
Abstract 2741
Chronic myeloid leukemia (CML) is the best and most successful disease model for tyrosine kinase inhibitor (TKI). The mechanism of BCR-ABL leading transformation and signaling transduction networks have been intensively characterized over decades. However, resistance to TKIs remains a challenge in management of patients with CML. A better understanding BCR-ABL signaling network will lead to a better therapy.
Here we report the discovery of a novel downstream target of BCR-ABL signalling, PRL-3 (PTP4A3), an oncogenic tyrosine phosphatase. Analysis of CML cancer cell lines and CML patient samples reveals the upregulation of PRL-3. A search of Gene Expression Atlas (http://www.ebi.ac.uk/gxa/gene/ENSG00000184489) identified the expression level of PRL-3 was highest in CML among 950 human cancer cell lines crossing 32 different types of cancers (Dataset code: E-MTAB-37), suggesting a potential role of PRL-3 in CML pathogenesis. Inhibition of BCR-ABL signalling either by Imatinib or by RNAi silencing BRC-ABL in CML cell line K562, KCL-22 and primary patient samples reduces PRL-3, in parallel with suppression of signal transducer and activator of transcription (STAT) pathway activities and increased cleavage of PARP, a hallmark of apoptosis. In contrast, the amount of PRL-3 protein remains constant or even increased in response to Imatinib treatment in drug resistant cells expressing BaF3-P210 T315I. Finally, analysis with specific shRNA demonstrated K562-shPRL-3 (shP) cells proliferated as much as 2-time lesser than K562-shControl (shC) at day 8 (p < 0.001). Colony-forming efficiency is an indicator of self-renewal capacity of leukemic cell. K562-shP cells also showed significantly impaired colony generating capacity by 3-fold compared to K562-shC (p < 0.001). These results indicate a critical role for PRL-3 in CML cell expansion and self-renewal.
In summary, the present study demonstrates that PRL-3 is remarkably upregulated in human CML cell lines, BCR-ABL transformed cell lines and primary CML patient samples. Our results highlight that PRL-3 is a novel downstream target of BCR-ABL pathway, which is crucial for BRC-ABL-mediated cell survival and self-renewal. These data support a functionally important role of PRL-3 in CML biology downstream of BCR-ABL and maybe a viable therapeutic target in BCR-ABL positive cells even in those with Imatinib resistant mutations.

Disclosures:
Off Label Use: Imatinib will be used as a tool to dissect BCR-ABL signaling.
Very Long-Term Follow-up Results of Imatinib Mesylate Therapy in Chronic Phase Chronic Myeloid Leukemia After Failure of Interferon Alpha Therapy
Authors: Alattar Mona Lisa , Cortes Jorge E. , O'Brien Susan , Garcia-Manero Guillermo , Faderl Stefan , Ravandi Farhad , Jabbour Elias , Shan Jianqin , Kantarjian Hagop M. 
Published: October 2019

Abstract
Abstract 2749

Background:
The long-term outcome of patients with chronic phase chronic myeloid leukemia treated with imatinib after failure of interferon alpha therapy has not been detailed. Patients and Methods: 368 patients were analyzed. Univariate and multivariate analyses for survival were conducted using standard statistical methods. Results: Overall, 247 patients (67%) achieved complete cytogenetic response (CCyR). Of 327 patients studied, 207(63%) achieved major molecular response (MMR), and 99 (30%) had undetectable BCR-ABL levels at some time on therapy. The estimated 10-year survival rate was 68%, progression-free survival rate 67%, and event-free survival rate 51%. By multivariate analysis, age ≥ 60 years, hemoglobin < 10g/dl, marrow basophils ≥ 5%, any peripheral blasts, and clonal evolution were independent adverse factors for survival. The estimated 7-year survival by the presence of none (n=154), 1–2 (n=190), or ≥ 3 factors (n=24) were 93%, 70%, and 25% respectively (p <0.01). Achievement of MMR, CCyR, or partial cytogenetic response at 12 months were associated with significantly better 10-year survival rate by landmark analysis (10-year survival 80–90%) vs. achieving minor cytogenetic response or complete hematologic response (10-year survival 55–65%) vs. other response (10-year survival 10%). Using landmark analysis to include imatinib response at 12 months, achievement of major cytogenetic response or better (hazard ratio 0.12; p< 0.001) and complete hematologic response or minor cytogenetic response (hazard ratio 0.36; p=0.003) were significant favorable prognostic factors. Conclusions: The estimated 10-year survival rate of 68% in patients with chronic myeloid leukemia receiving imatinib after interferon failure has improved.

Disclosures:
Cortes: Novartis: Consultancy; Novartis: Research Funding; BMS: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Kantarjian:Novartis: Consultancy; Novartis: Research Funding; Pfizer: Research Funding; BMS: Research Funding.
Evaluation of a New Nanoparticle-Based Lateral-Flow Immunoassay for the Exclusion of Heparin-Induced Thrombocytopenia (HIT),
Authors: Sachs Ulrich J. , von Hesberg Jakob , Santoso Sentot , Bein Gregor , Bakchoul Tamam 
Published: October 2019

Abstract
Abstract 3290

Background:
Heparin-induced thrombocytopenia (HIT) is an adverse complication of heparin caused by HIT antibodies (abs) that recognize platelet factor 4-heparin (PF4/hep) complexes. Several laboratory tests are available for the confirmation and/or refutation of HIT. A reliable and rapid single-sample test is still pending. Objectives: To evaluate a new lateral-flow immunoassay based on nanoparticle technology. Patients/methods: A cohort of 452 surgical and medical patients suspected of having HIT was evaluated. All samples were tested in two IgG-specific ELISAs, in a particle gel immunoassay (PaGIA) and in a newly developed lateral-flow immunoassay (LFI-HIT) as well as in a functional test (HIPA). Clinical pre-test probability was determined using 4T's score. Results: Platelet-activating antibodies were present in 34/452 patients, all of whom had intermediate to high clinical probability. PF4/hep abs were detected in 79, 87, 86, and 63 sera using the four different immunoassays. The negative predictive values (NPV) were 100% for both ELISA tests and LFI-HIT but only 99.2% for PaGIA. There were less false positives (n=29) in the LFI-HIT compared to any other test. Additionally, significantly less time was required to perform LFI-HIT (median time, 11 min 30 sec) than to perform the other immunoassays. Conclusion: A newly developed lateral-flow assay, LFI-HIT, was capable of identifying all HIT patients in a cohort in a short period of time. Beside an NPV of 100%, the rate of false-positive signals is significantly lower with LFI-HIT than with other immunoassay(s). These performance characteristics suggest a high potency in reducing the risk and costs in patients suspected of having HIT.

Disclosures:
No relevant conflicts of interest to declare.
Increased Heparanase Level and Procoagulant Activity in Orthopedic Surgery Patients Receiving Prophylactic Dose of Enoxaparin,
Authors: Peled Eli , Robitzki Alexie , Axelman Elena , Norman Doron , Brenner Benjamin , Nadir Yona 
Published: October 2019

Abstract
Abstract 3333

Background:
Orthopedic hip and knee surgeries are followed by a hypercoagulable state. Heparanase is implicated in inflammation, coagulation activation and angiogenesis. Recently, heparanase was shown to directly interact with tissue factor (TF) and to enhance generation of factor Xa (Nadir et al, Haematologica, 2010). In addition, an assay evaluating heparanase procoagulant activity has been lately developed (Nadir et al, Thromb Res, 2011). In the present study, heparanase level and procoagulant activity in patients undergoing orthopedic surgery were assessed. Methods: The study group included 50 orthopedic patients. Thirty one patients underwent hip operation and 19 had knee surgery. Fifteen individuals suffered from traumatic hip fractures and 35 had osteoarthrosis of hip or knee joints. All patients received a prophylactic dose of enoxaparin starting 6–8 hours post operation and lasting for 5 weeks. Plasma samples were drawn preoperatively and at 1 hour, 1 week and 1 month post surgery. Samples were tested for heparanase levels by ELISA and TF/heparanase complex activity, TF activity, heparanase procoagulant activity, factor Xa and thrombin levels were estimated using chromogenic substrates. Results: Heparanase levels were significantly higher 1 hour and 1 week postoperatively compared to preoperative levels (p<0.05, p<0.005, respectively). The most dramatic changes were observed in heparanase procoagulant activity, reaching a 2-fold increase 1 week postoperatively and a 1.7-fold increase 1 month after surgery (p<0.0001 and p<0.0001, respectively). Levels of factor Xa and thrombin did not significantly change. Conclusions: Heparanase is found to be involved in coagulation activation of orthopedic surgery patients, with heparanase procoagulant activity being highest 1 week postoperatively and still remaining high 1 month after operation. Consideration of extending prophylactic anticoagulant therapy or evaluation of heparanase procoagulant activity may potentially prevent late thrombotic events in this patient population.

Disclosures:
No relevant conflicts of interest to declare.
Stress-Induced Activation of Dormant Hematopoietic Stem Cells In Vivo,
Authors: Essers Marieke , Lutz Raphael , Thamm Stefanie , Uckelmann Hannah , Wurzer Stephan , Trumpp Andreas 
Published: October 2019

Abstract
Abstract 3390
Maintenance of the blood system is dependent on dormant haematopoietic stem cells (HSCs), which are characterized by pluripotency and life long self-renewal capacity. In order to both maintain a supply of mature blood cells and not exhaust HSCs throughout the lifespan of the organism, most adult HSCs remain quiescent and only a limited number are cycling at any given time. The balance between self-renewal and differentiation of HSCs is controlled by external factors such as chemokines, as well as interactions of HSCs with its niche environment.
We have recently shown that the cytokine IFNa very efficiently activates dormant HSCs in vivo. Within hours after treatment of mice with IFNa HSCs exit G0 and enter the active cell cycle. In general, IFNa is produced in response to viral infections by cells of the immune system, and plays an important role in the host defense against the viral infection. We now questioned whether endogenous IFNa is also produced in response to other forms of bone marrow stress and whether this affects the proliferation rate of HSCs. To monitor IFNa production in the bone marrow in vivo, we have generated MxCre; ROSA-R26-EYFP mice and found that treatment with both the chemotherapeutic agent 5-FU as well as the endotoxin LPS leads to the production of IFNa in HSCs and progenitors. In addition, LPS treatment in vivo induced a strong increase in proliferation of HSCs. In contrast to the direct effect of IFNa on HSCs, in vivo and in vitro experiments have shown that the LPS induced activation of HSCs is triggered via an indirect effect of LPS on CD11b+ cells in the bone marrow. Activation of these cells via TLR4 signaling then results in increased proliferation of the HSCs, a mechanism we are currently investigating in more detail.
Interestingly, LPS induced activation correlated with increased expression of Sca-1 on HSCs, similar to the increased Sca-1 expression upon IFNa treatment. As for IFNa, the upregulation of Sca-1 is required for LPS induced proliferation, since Sca-1−/− mice do not respond to LPS stimulation. Furthermore, cDNA array comparisons between HSCs treated with IFNa or LPS suggest a more common mechanism of activation, independent of the source leading to the activation.
In summary, these data suggest that in addition to viral infection also other forms of bone marrow stress, like LPS, result in activation of quiescent HSCs in the bone marrow, probably via similar mechanisms. Furthermore, both IFNa and LPS induced activation of HSCs are dependent on the up-regulation of Sca-1, suggesting a more general role for Sca-1 in the activation of stem cells.

Disclosures:
No relevant conflicts of interest to declare.
Core Transcriptional Regulatory Circuit Controlled by the TAL1 Complex in T-Cell Acute Lymphoblastic Leukemia,
Authors: Sanda Takaomi , Lawton Lee N , Barrasa M Inmaculada , Fan Zi Peng , Ahn Yebin , Young Richard , Look A. Thomas 
Published: October 2019

Abstract
Abstract 3453
Aberrant expression of TAL1 is one of the most frequent abnormalities in T-cell acute lymphoblastic leukemia (T-ALL), yet little is known about the transcriptional network controlled by this oncogenic transcription factor, posing a major obstacle to understanding T-ALL pathogenesis. Here we identify the core transcriptional regulatory circuit controlled by TAL1 and its regulatory partners HEB, E2A, GATA3 and RUNX1 in T-ALL cells. We determined direct transcriptional targets of TAL1 and its regulatory partners by ChIP-seq analysis, and found that TAL1 binds to the majority of HEB- and E2A-enriched regions and that these commonly bound regions are frequently overlapping with the GATA3- and RUNX1-enriched regions. We found that TAL1 forms an interconnected auto-regulatory loop with its partners, which likely contribute to the sustained upregulation of its direct target genes. TAL1 core regulatory circuit activates genes involved in T-cell development and hematopoesis. Microarray gene expression analysis revealed that TAL1 and GATA3 predominantly act as positive regulators of the expression of their direct target genes in T-ALL. Importantly, we found the MYB oncogenic transcription factor is directly activated by the TAL1 complex and positively regulates many of the same target genes, thus forming a feed-forward positive regulatory loop that further promotes the TAL1-regulated oncogenic program. Moreover, we found that a specific subset of TAL1 target genes are oppositely regulated by TAL1 and its obligate partner proteins E2A and HEB, uncovering a leukemogenic pattern that previously emerged from studies in murine models. These findings underscore the importance of TAL1 as a critical regulator of an aberrant gene expression program in T-ALL, and indicate how these networks maintain the malignant state in thymocytes.

Disclosures:
No relevant conflicts of interest to declare.
CD64 Expression Is An Independent Adverse Prognostic Factor in Pediatric Acute Myeloid Leukemia Treated with Allogeneic Stem Cell Transplantation,
Authors: Albitar Maher , Alseraihy Amal , Ayas Mouhab , Al-Jefri Abdullah , Al-Ahmari Ali , Belgaumi Asim F , Walter Claudia Ulrike , Nounou Randa , Khalil Salem , Bakshi Nasir , Owaidah Tarek , El-Solh Hassan 
Published: October 2019

Abstract
Abstract 3525

Background:
The Fcγ receptor I alpha chain (CD64) is usually used as a monocytic marker in immunophenotyping acute myeloid leukemia (AML). The clinical relevance of CD64 expression is controversial and has been reported to be associated with good outcome in the adult population in one large study. The prognostic relevance of CD64 in pediatric AML is not known. More importantly, the outcome is not known when patients expressing CD64 on the surface of their blasts are considered for allogeneic hematpoietic stem cell transplantation (HSCT). We investigated whether HSCT can neutralize the adverse effects of CD64 expression in pediatric AML patients.

Methods:
Immunophenotype data of 53 pediatric patients with AML, all treated with allogeneic HSCT, was reviewed. The expression of the CD64 on the blast population as determined by flow cytometry was correlated with clinical data and outcome. The median age of patients was 8 years (range: 8 months–14 years) and included 40 (75%) patients transplanted in first complete remission (CR1). Thirty eight (72%) of all patients had intermediate-risk cytogenetics and the remaining (28%) had adverse-risk cytogenetic abnormalities. Only 6 of the 53 patients (11%) had MLL rearrangement as determined by karyotyping and FISH studies.

Results:
Fifteen (28%) of all studied patients expressed CD64 on the surface of the blasts at diagnosis. Patients with CD64 expression had significantly shorter overall survival (P=0.005) with median survival of approximately 9 months while the median survival in the CD64 negative patients has not been reached. Similarly, CD64 positive patients had significantly shorter event free survival (EFS) (P=0.004). Even when we considered only patients treated with in CR1 who had HSCT, the OS and EFS for the CD64 positive patients were both significantly shorter (P=0.01 and P=0.009, respectively). The median survival was 8.85 months for the CD64 positive patients, while the median has not been reached in the CD64 negative patients. Multivariate analysis including CD64 expression and cytogenetic risk identified CD64 expression as an independent prognostic factor for survival and EFS, while cytogenetic-risk stratification became no longer a predictor.

Conclusion:
Our data suggests that the expression of CD64 in pediatric AML is a significant independent poor prognostic factor in pediatric AML patients when treated with HSCT. Most of the CD64 positive patients die in their first year after HSCT and the management of these patients should be modified to address early death in this group of patients.

Disclosures:
No relevant conflicts of interest to declare.
Phase I Trial of the Oral Poly (ADP-ribose) Polymerase (PARP) Inhibitor Veliparib (ABT-888, V) Combined Wtih Topoecan (T) and Carboplatin (C) for Adults with Relapsed and Refractory Acute Leukemias,
Authors: Pratz Keith W. , Kaufmann Scott H. , Litzow Mark R. , Ji Jiuping , Chen Alice , Rudek Michelle A , Karp Judith E. 
Published: October 2019

Abstract
Abstract 3634
PARP is activated in response to DNA single strand (SS) breaks and is pivotal to the base excisional repair pathway for chemotherapy-damaged DNA. The orally bioavailable PARP inhibitor V delays DNA repair and potentiates the cytotoxicity of multiple classes of chemotherapy drugs including topoisomerase I inhibitors and platinating agents in leukemia cell lines. A previous clinical trial of T+C yielded promising results in adults with refractory acute leukemia at the maximum tolerated dose (MTD) of T 1.6 mg/m2/d + C 150 mg/m2/d by intravenous continuous infusion (IVCI) × 120 hrs. We are conducting a Phase I dose-escalation trial of V given orally twice daily Days 1–8 with T+C given by 120 hr IVCI Days 3–7.
Deaths due to myocardial infarct and splenic infarcts with ascites occurred in one pt each when C 150 mg/m2 was added to V 10 mg BID and T 1.3 mg/m2, resulting in adjustment of the dose escalation schema for C and T.Dose levelVeliparib Oral Daily Days 1–8Topotecan Continuous IV Days 3–7Carboplatin Continuous IV Days 3–7Clinical Responses/#Pts1A10 mg p.o. BID1.0 mg/m2/day—1/3(CRi)1B10 mg p.o. BID1.3 mg/m2/day—1/3(CR)2A10 mg p.o. BID1.3 mg/m2/day150 mg/m2 IV0/42C10 mg p.o. BID1.0 mg/m2 IV120 mg/m2 IV2/6(CRi, PR)2D10 mg p.o BID1.2 mg/m2 IV120 mg/m2 IV1/6(PR)2E10 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CRi)3C20 mg p.o. BID1.0 mg/m2 IV120 mg/m2 IV0/63D20 mg p.o BID1.2 mg/m2 IV120 mg/m2 IV2/6(CR, PR)3E20 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CR)440 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CR)5§80 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/4(CR, CRi)
Of 56 pts treated at doses of V 10–80 mg orally BID Days1–8 and T 1.0–1.2 mg/m2/d + C 120–150 mg/m2/d for 120 hrs IVCI Days 3–7, 25 (45%) have experienced > grade 3 non-hematologic toxicity, 6(11%) have had grade 4 toxicity and 1 (4%) died from sepsis with multi-organ failure. Overall response rate is 27% (8CR, 4 CRi, 3 PR), with 7 in relapsed AML, 7 in refractory AML and 1 refractory ALL. Pharmacokinetic (PK) studies in pt plasma, marrow supernatant, and marrow blasts demonstrated that V is detectable in marrow supernatant and cells, does not accumulate with multiple dose administrations in plasma but does in marrow, and is not altered by T or C administration. Nuclear staining for phosphorylated histone H2AX (γH2AX) demonstrated that V 10 mg BID increased DNA damage by > 2-fold in 11/22 (50%) on Day 1 and 13/18 (72 %) on Day 4 after 24 hrs of T+C. A PAR ELISA demonstrated that V suppresses PAR levels to <50% of pretreatment values in 30/41 (73%) blood and 3/4 patients at V 40mg per day dose level had greater than 80% suppression of PAR. The MTD has not been reached and dose escalation is ongoing.

Disclosures:
No relevant conflicts of interest to declare.
Preliminary Results of An Ongoing Phase I Trial of Oral Belinostat a Novel Histone Deacetylase Inhibitor in Patients with Lymphoid Malignancies,
Authors: Zain Jasmine M. , Foss Francine M. , Diefenbach Catherine S. , Petrylak Daniel , Narwal Ameet , Neylon Ellen , Knoblauch Poul , O'Connor Owen A. 
Published: October 2019

Abstract
Abstract 3710

Background:
Belinostat (Bel) is a pan class I/II histone deacetylase inhibitor with broad preclinical activity. A phase I study of oral Bel in patients (pts) with solid tumors identified a maximum tolerated dose (MTD) of 750 mg orally (PO) daily on days (d) 1–14, of an every 21 day cycle. An allowance for intra-patient dose escalation was permitted as long as the higher dose level was deemed safe and not the maximum administrable dose. The current study was initiated to assess the safety and dosing of Bel in patients with relapsed or refractory Hodgkin and non-Hodgkin Lymphoma. Methods: 3–6 pts per dose cohort were enrolled on study, at the following doses: A 750; B 1000; C 1250; D1500;E 1750; F 2000mg/d. Pts who met eligibility criteria (ANC =; plts =) with evaluable disease were eligible. Definition of dose limiting toxicity (DLT) included: related non-hem grade (gr) 3/4 tox; gr 4 neutropenia > 5 d or with fever > 100.5 °F; gr 4 thrombocytopenia > 7 d.

Results:
28 pts, median age 48 (range 21–82),prior regimens: median 5,5 (range 0–13), (17 had BM transplants, including 5 pts with allogeneic) have been enrolled. Diagnoses include: HD (12 pts), mantle cell lymphoma (MCL;5 pts), other NHL (11 pts). Most frequent adverse events seen in > 50% of patients (regardless of attribution or gr) in 28 pts fully evaluable for toxicity: diarrhea (25 pts), anorexia/decreased appetite (24 pts), fatigue (23 pts), nausea (18 pts), vomiting (18 pts), cough (17 pts) and fever (15 pts). Non-hem gr 3 events included diarrhea in 9 pts (evenly distributed over the co-horts), grade 3 diarrhea at 1500 and 2000 mg dose were among the 4 DLT's. 5 pts with gr 3/4 thrombocytopenia (shift from baseline) were seen in cohort C, D, E. 16 pts are evaluable to date, and include r, 1 CR (duration: 2+cycles)in NHL patient, 1 PR (duration: 8 cycles) in HD patient, and stable disease have been noted in 12 patients (duration: 1–24 cycles, median 1,5). Aside from the 1 CR and 1 PR, tumor shrinkage between 25– 50% was noted in 8 pts.

Conclusions:
Oral Bel can be delivered safely with a d 1–14, q3w schedule in pts with lymphoma at a daily dose higher than what has been established for pts with solid tumors. MTD for lymphoma pts was established at 1500 mg/d 1–14, q3w. The safety profile and early tumor shrinkage noted in both HD, MCL and other NHL warrants continued evaluation of Bel, especially in combination with other active compounds.

Disclosures:
Foss: esai, allos, merck, celgene: Consultancy, Research Funding. Knoblauch:Topotarget: Employment.