bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeting Pre-Leukemic Stem Cells in T-Acute Lymphoblastic Leukemia
Authors: Gerby Bastien , Veiga Diogo F.T , Krosl Jana , Ouellette Julianne , Haman André , Lavoie Geneviève , Fares Iman , Tremblay Mathieu , Litalien Véronique , Ottoni Elizabeth , Kosic Milena , Geoffrion Dominique , Ryan Joël , Maddox Paul , Chagraoui Jalila , Marinier Anne , Hébert Josée , Sauvageau Guy , Kwok Benjamin H , Roux Philippe P , Hoang Trang 
Published: October 2019

Abstract
Current chemotherapy of pediatric T cell acute lymphoblastic leukemia (T-ALL) efficiently reduces the tumor mass with, however, undesirable long term consequences and remains ineffective in adolescent and adult T-ALL. Furthermore, relapse can be caused by pre-leukemic stem cells (pre-LSCs) that were spared by current protocols and evolved to malignancy. A distinctive characteristic of pre-LSCs is their critical dependence on interactions with the microenvironment for survival, which guided our strategy to target pre-LSCs using niche-based screening assays.
Using transgenic mouse models that closely reproduce the human disease, we showed that the SCL/TAL1 and LMO1 oncogenic transcription factors establish a pre-leukemic state by reprogramming normal pro-T cells into aberrantly self-renewing pre-LSCs (Gerby et al. PloS Genetics, 2014). We now provide direct evidence that pre-LSCs are much less chemosensitive than leukemic blasts to current drugs, due to a distinctive lower proliferative state as assessed by real-time imaging in a competitive assay. We therefore designed a robust protocol for high-throughput screening (HTS) of compounds targeting primary pre-LSCs that are maintained on stromal cells engineered for optimal NOTCH1 activation to mimick the thymic microenvironement. The multiparametric readout takes into account the intrinsic complexity of primary cells to specifically monitor pre-LSCs. We screened a targeted library of 1904 compounds and identified UM0119979 that disrupts both cell autonomous and non-cell autonomous pathways: UM0119979 abrogates pre-LSC viability and self-renewal activity in vivo by specifically inhibiting the translation of MYC, a downstream effector of NOTCH1, and preventing SCL/TAL1 activity. In contrast, normal hematopoietic stem/progenitor cells remain functional. Moreover, in vivo administration of UM0119979 efficiently reduced the leukemia propagating activity of primary human T-ALL samples in xenografted mice. Finally, in addition to SCL-LMO-induced T-ALL, our results reveal a novel possibility of therapeutic intervention in MYC-dependent hematologic malignancies.
In summary, our screening assay, built on the genetic dependencies of pre-LSCs, revealed their vulnerabilities to compounds that inhibit both the primary oncogenes and non-cell autonomous pathways triggered by the microenvironment. The results illustrate how recapitulating tissue-like properties of primary cells in high throughput screening is a promising avenue for innovation in cancer chemotherapy.

Disclosures
No relevant conflicts of interest to declare.
Overexpression of Notch1 Inducing T-ALL Phenotype and Promoting Angiogenesis in Zebrafish
Authors: Shen Lijing , Chen Fangyuan , Qing Kai , LI Xiang , LIU Haiyan 
Published: October 2019

Abstract
Aim: Abnormal activated Notch1 gene is familiar to us as a poor prognostic factor in T cell acute lymphoblastic leukemia (T-ALL). This in vivo study aimed to establish a stable line of zebrafish overexpressing the human Notch1 gene under the control of a heat stress-inducible promoter, and explore its roles in etiology of T-ALL, and in tumor-related angiogenic process.
Methods: Rag2-ICN1(intracellular domain Notch1)-RFP Plasmid was constructed and injected into the embryos Tg (fli1-EGFP) in the one cell stage to construct the double-fluorescence tracer and double transgenic zebrafish, named as Tg(ICN1:RFP/fli1:EGFP). Expression of ICN1 gene and its influence on zebrafish were assayed through fluorescence microscope, RT-PCR, western-blot, FCM, blood smear, RFQ-PCR and drug treatment.
Results: Twenty of the 867 (2.3%) mosaic F0 zebrafish embryos were identified to be the germline transgenic zebrafish, including 9 males and 11 females. FCM and peripheral blood smears suggested a significant reduction in the proportion of red blood cells and a increasing of lymphocyte ratio in transgenic zebrafish as compared to control group. RFQ-PCR shows that lymphocytic regulatory factor ikaros, rag1 and lck were significantly reduced, indicates obvious differentiation obstacle in lymphoid lineages. These results were absolutely consistent with the results of FCM and peripheral blood smear. Quercetin suppressed the proliferation activity of T-ALL cell lines and induced apoptosis in a time- and dose-dependent way, meanwhile, quercetin can inhibited Notch1, Hes1, Dll4 and VEGF gene and these proteins expression in A3 and Molt-4 cells (T-ALL cell line). Furthermore, quercetin displayed a significantly reduction in the length of ISV and SIVs in Tg(rag2-ICN1-RFP/fli1-EGFP) zebrafish).
Conclusions: The above results induced by overexpression of Notch1 gene closely resemble the main aspects of human T-ALL, suggesting that Notch1 plays a role in the etiology of AML. Some key lymphocytic regulatory factors were apparently changed, which indicates obvious differentiation obstacle in lymphoid lineages and accompanied with the increasing small lymphocytes and precursors. Quercetin inhibited the proliferation and induced apoptosis of T-ALL cell lines as well as inhibition of zebrafish angiogenesis by downregulating the expression of Dll4/Notch1 and VEGF pathways. Therefore, this Notch1 transgenic zebrafish model facilitates dissection of Notch1-mediated signaling in vivo, and enables high-throughput scale screens to identify the potential therapeutic targets.

Disclosures
No relevant conflicts of interest to declare.
Risks and Benefits of Rituximab Maintenance in Elderly Patients with Advanced Follicular Lymphoma
Authors: Savard Marie-France , Johnson Nathalie A. 
Published: October 2019

Abstract
Introduction: Based on the PRIMA trial (Lancet 2010; 377: 42-51), rituximab maintenance following induction rituximab-based chemotherapy is the standard of care in patients with advanced follicular lymphoma (FL) because it extended the 3-year progression free survival (PFS) from 58% to 75%, with a low rate of infection (<5%). However, this study was conducted in young patients (median age 57 years old) and the benefits and risks of the maintenance are unknown in elderly patients.
Methods: We reviewed the clinical characteristics, outcome and complications of 62 advanced FL patients selected based on having successfully completed induction chemotherapy and initiated maintenance rituximab at the Jewish General Hospital between 2007 and 2014. The age cut off of ≥75 years old at the time of treatment was defined as "elderly". We compared characteristics of the two groups using the χ2 test and calculated PFS using the Kaplan-Meier method and log-rank test.
Results: In total, 9/62 (15%) patients were "elderly" and 53/62 (85%) were "young", with median ages of 79 (75-87) and 55 (30-74) years old, respectively. Elderly patients had more adverse prognostic features compared to younger patients: B symptoms (4/9 vs 7/53, p=0.023), elevated lactate dehydrogenase (5/9 vs 9/51, p=0.013), lower hemoglobin (5/9 vs 3/52, p<0.001) and poor performance status (3/9 vs 1/53, p<0.001). The mean PFS was lower in elderly patients (25 months vs 65 months, p=0.05). The 3-year PFS in the young group was 80%. Toxicities were higher in the elderly group: grade 3-4 neutropenia (3/9 vs 5/53, p=0.05) and infections (5/9 vs 13/52, p=0.063).
Conclusion: Elderly patients had more adverse prognostic factors and a significantly inferior PFS with rituximab maintenance compared to younger patients. The rates of infections were higher than those reported in the PRIMA trial. Maintenance rituximab may not benefit elderly patients with advanced FL.

Disclosures
No relevant conflicts of interest to declare.
Mutations in TP53 Gene Is Independent Prognostic Factor for High Grade B-Cell Lymphoma
Authors: Misyurina Anna Evgenevna , Misyurin Vsevolod Andreevich , Misyurin Andrey Vitalievich , Kovrigina Alla Mikhailovna , Kravchenko Sergey Kirillovich , Baryakh Elena Alexandrovna , Magomedova Aminat Umaraskhabovna , Pushkova Elena Nikolaevna , Parovichnikova Elena N. , Savchenko Valery Grigorievich 
Published: October 2019

Abstract
Background. TP53 mutations were described to have a negative impact on prognosis of patients with B-chronic lymphoid leukemia and diffuse large cell lymphoma. However, a role of TP53 mutations in high-grade B-cell lymphomas (HGL) is not well defined in context of other genetic aberrations.
Materials and methods. 23 patients (7 males and 16 females) had diagnosis of HGL were treated in National Research Center for hematology, Moscow, Russia. Median age was 49 years old (30-76). 5 patients had HGL with c-MYC (MYC-R) and BCL2 genes rearrangements and 2 - HGB with MYC-R and BCL6 rearrangements. 17 (74%) patients had MYC-R, 11/23 (48%) had double expresser lymphoma (MYC≥40%, BCL2≥50%) (DE). Median of observation time was 29,1 months (6,3-99,8). 19 (82%) of patients had IPI score 3-5 points. 16 patients underwent LM-B-04 with rituximab (Table 1), 5 - R-(DA)-EPOCH, 2 - R-CHOP-21. In 5 cases autologous stem cell transplantation was performed. Sanger sequencing was performed to identify mutations in exons 5-8 of TP53 gene using DNA extracted from formalin fixed paraffin embedded tissue («Extra-DNA» kit, «Genetechnology» LLC). Primers to TP53 gene were synthesized based on nucleotide sequences data available online on website ncbi.com by «Evrogene». To evaluate an influence of such factors as TP53 mutation (TP53mut), MYC-R, DHL, DE, gender, therapy on overall survival (OS) and time to progression (TTP) were performed multivariate dispersion analysis and Cox regression analysis (STATISTICA 10).
Results: 8 (35%) cases with TP53mut were identified: c.535C>T 45,6% p.H179Y, c.524G>C 15,6% p.R175P, c.743G>A 75,6% p.R247Q, c.487T>A 25,2% p.Y163N, c.824G>A 75% p.C275Y, c.713G>A 87,7% p.C238Y, c.745A>G 31,9% p.R249G, c.639A>G 41,8% p.R213R. 7/8 of them harbored MYC-R, 2/8 had DHL. In univariate (Picture 1, 2) and multivariate analysis pts harboring TP53mut had worse OS (median OS was 6,2 (0,7-9,5) vs 25,5 (0,7-99,8) months, p=0,004) and shorter TTP (median TTP 3,5 (0,7-9,5) vs 23,1 (0,7-99,8) months, p=0,027) than patients without TP53mut. DHL status had also an adverse effect on OS with lower significance than in pts with TP53mut (p=0,022). Adverse effect of TP53mut trends to play a role in combination with c-MYC gene rearrangement, thus5 pts TP53mut/MYC-R had shorter TTP than 5 DHL pts (3,4 (1,1-9,5) vs 7,3 (0,6-67,1) months, p=0,07).
Conclusion: High-grade lymphoma has a more powerful and independent prognostic factor than double-hit status - TP53 mutation that contribute inferior prognosis. This factor shouldn't be underestimated in routine diagnostics because of its frequency and requirement of a different therapeutic approach.

Disclosures
No relevant conflicts of interest to declare.
High Frequency of Loss of Heterozygosity and Chromosomal Imbalances in Patients with Myelofibrosis
Authors: Junior Milton Rego de Paula , Mazzeu Juliana Forte , Taylor Aline Pic , Oliveira Silviene , Nonino Alexandre , Mascarenhas Cintia Do Couto 
Published: October 2019

Abstract
Myelofibrosis (MF) is a clonal hematopoietic stem cell disorder belonging to the non-chronic-myeloid-leukemia myeloproliferative neoplasms. Cardinal features of myelofibrosis include extramedullary hematopoiesis, hepatosplenomegaly and cytopenias. The disease can occur de novo as primary MF or result from the progression of polycythemia vera or essential thrombocythemia with no differences in clinical or histological characteristics. Though several large chromosome abnormalities have been described in patients with myelofibrosis there are no previous studies screening for both CNVs and LOH (loss of heterozygosity) in patients with MF. We studied 11 patients using CytoScan platform (750k or HD- Affymetrix). This platform allows the identification of copy number variations as well as segments of loss of heterozygosity. Forty-five percent (5/11) presented pathogenic/possibly pathogenic CNVs and 72% (8/11) presented large segments of loss of heterozygosity (>10Mb). Two patients had a single CNV without any LOH. Two patients had a single LOH. All others have multiple LOH with (3) or without (4) CNVs. The most frequent abnormality was LOH of 9p (3/11) and deletion 13q (2/11). All other alterations were non-recurrent. One patient had a small deletion including exons 1 and 2 of NOTCH2, a gene known to be involved in hematological malignancies. The most frequent abnormality reported in the literature is 20q deletion. In our cohort only one patient had the 20q deletion and also had multiple complex chromosome rearrangements on chromosomes 7 and 12 and a large LOH on chromosome 3p. The study shows that CNV and LOH are frequent and may be involved in pathogenesis of the disease. However, the role of these changes in the pathogenesis are not yet clear.

Disclosures
No relevant conflicts of interest to declare.
Monocyte-Derived Macrophages Are Impaired in Myelodysplastic Syndrome
Authors: Han Yu , Wang Huaquan , Shao Zonghong 
Published: October 2019

Abstract
The myelodysplastic syndrome (MDS) comprises a group of clonal hematopoietic stem cell diseases characterized by cytopenia, dysplasia in one or more of the major myeloid lineages, ineffective hematopoiesis, and increased risk of development of acute myeloid leukemia (AML). Macrophages are innate immune cells that ingest and degrade abnormal cells, debris, and foreign material and orchestrate inflammatory processes. Tumor-associated macrophages (TAMs) play an important role in the pathophysiology of human malignancies. They support growth of cancer cells by promoting angiogenesis, inhibiting tumor cell apoptosis and anti-tumor immune reactions. In this study, we analyzed the role of macrophages from MDS patients in vitro. Macrophages were induced from peripheral blood of patients with MDS via granulocyte macrophage colony-stimulating factor (GM-CSF). Compared with that in the normal control group, the number of monocytes increased in MDS patients. However, the monocytes showed impaired ability to induce macrophages and the number of macrophages induced from MDS samples was lower. Further, we demonstrated that the ex vivo phagocytic function of macrophages from MDS patients was impaired and levels of reorganization receptors CD206 and signal regulatory protein alpha (SIRPα) were lower. Levels of inducible nitric oxide synthase(iNOS) secreted by macrophages in MDS were increased. In conclusion, monocyte-derived macrophages are impaired in myelodysplastic syndromes.

Disclosures
No relevant conflicts of interest to declare.
Frequency of Amyloid Subtyping Among Patients with Immunoglobulin Light-Chain Amyloidosis Referred for High-Dose Chemotherapy and Autologous Stem Cell Transplant
Authors: Cowan Andrew J. , Coffey David G. , Hyun Teresa S. , Becker Pamela S. , Green Damian J. , Holmberg Leona A , Gopal Ajay K , Libby Edward N. 
Published: October 2019

Abstract
Background:
The amyloidoses comprise a heterogeneous group of diseases characterized by misfolding of amyloidogenic proteins and subsequent deposition as amyloid fibrils. To date, over 30 proteins are known to be amyloidogenic (Sipe Amyloid 2014). Immunoglobulin light chain (AL) amyloidosis, a plasma cell dyscrasia, is the most common subtype. The standard diagnostic algorithm in AL amyloidosis is to obtain a biopsy of a clinically involve organ, and once Congo red positivity is confirmed, perform subtyping analyses with immunohistochemistry or mass spectrometry. Accurate subtyping of amyloidosis is essential to appropriate treatment, as misdiagnosis occurs in up to 10% of patients and may lead to inappropriate administration of chemotherapy (Comenzo Blood 2006; Lachmann NEJM 2002). We sought to determine the patterns of amyloid subtyping among patients with a diagnosis of AL amyloidosis referred to a tertiary referral center for HDM/SCT.
Methods:
Sequential patients with confirmed amyloidosis, age ≥ 18 years who underwent HDM/SCT between 2001 and 2014 at the Fred Hutchinson Cancer Research Center and University of Washington Medical Center were eligible. Presence of a Congo red-positive biopsy for each patient referred for transplant was confirmed and the pathology reports and medical records were reviewed to determine if subtyping was performed, and which modality was used.
Results:
Fifty-one patients with AL amyloidosis were referred for transplant; of these, 45 proceeded with HDM/SCT. The organ systems most commonly involved were renal in 34/51, and gastrointestinal in 5/51. Of the biopsies, subtyping was performed in 35 (68.6%), and no subtyping was performed in 16 patients (31.3%). Immunofluorescence was the most common modality used for subtyping in 33 biopsies (94.2%) and laser capture/mass spectrometry (LC/MS) was used in 2 patients (5.7%). All patients had evidence of a clonal plasma cell dyscrasia by bone marrow biopsy and peripheral blood testing. Of the patients without subtyping, 8 (50%) were diagnosed before 2008.
Discussion:
Misdiagnosis of amyloidosis due to a lack of appropriate subtyping is a well-described and ongoing problem for patients with amyloidosis. These data suggest that definitive subtyping is still not routinely performed in the evaluation of amyloidosis. At our center, efforts to standardize the evaluation of Congo-red positive biopsies using definitive typing are underway.

Disclosures
Gopal: Seattle Genetics: Research Funding.
The Incidence of Adrenal Insufficiency in Myeloma Patients Receiving Pulse-Dose Dexamethasone
Authors: Afrough Aimaz , Sidorski Amy , Salvatori Roberto , Borrello Ivan 
Published: October 2019

Abstract
Introduction: Glucocorticoids (GC's) are major drugs in the treatment of multiple myeloma (MM). Chronic administration of supra-physiological doses of GC's suppresses the hypothalamus-pituitary-adrenal (HPA) axis and is associated with secondary adrenal insufficiency (AI). In MM, GC's are usually administered in weekly high dose pulses. Due to long GC-free periods in such therapy, GC-induced AI is not usually considered to be a consequence of GC therapy in MM (Krasner, AS. JAMA, 1999. 282(7): p. 671-6). Here we report on the incidence of AI in MM patients treated at our center with pulse-dose GC.
Methods: This is a retrospective cross-sectional study of patients with MM treated with GC-based regimens. Patients were required to have at least a random serum cortisol or a standard 250 mcg ACTH stimulation test result available in their medical record during dexamethasone-based chemotherapy. Patients were excluded if they were on dexamethasone more than 1 day a week, were lost to follow-up, had prior use of synthetic progestational agents such as megestrol or had been on oral glucocorticoids for any other medical indication. Diagnosis of AI was established by a frankly low AM serum cortisol level (<3 ug/dL) or an inadequate cortisol response to ACTH stimulation test (Salvatori, R. JAMA, 2005. 294(19): p. 2481-8).
Results: A total of 45 patients were included in this study with median age of 62 (range, 49-89). Fifteen (33.3%) of patients were diagnosed with AI. The median random cortisol level in AI group was 2.3 ug/dL (range, 0.3-7.4 ug/dL) compared to 9.9 ug/dL (range, 1.0-21.2 ug/dL) in the non-AI group. The median time between the last dexamethasone dose and the serum cortisol assay was 5 days (range, 1-21). The median number of GC-based chemotherapy cycles taken before diagnosis of AI was 15 (range, 2-60). The median cumulative dexamethasone consumption was 1280 mg (range, 180-5220 mg). There was no correlation between developing AI and dose or duration of dexamethasone treatment. We observed clinical trend between cumulative doses of ≥1500 mg (P= 0.055) or use of clarithromycin (P=0.079) and developing AI, without reaching a statistically significant difference.
Conclusion: The rate of AI was 33% among patients with MM on weekly pulse-dose dexamethasone. As such, patients should be periodically evaluated for this to enable early detection and proper management.

Disclosures
Borrello: BMS: Honoraria, Research Funding; WindMIL Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Celgene: Honoraria, Research Funding, Speakers Bureau.
EZH2 Inhibitors Are Broadly Efficacious in Multiple Myeloma As Single Agent and in Combination with Standard of Care Therapeutics
Authors: Arora Shilpi , Williamson Kaylyn , Apte Shruti , Balachander Srividya , Busby Jennifer , Hatton Charlie , Bryant Barbara , Trojer Patrick 
Published: October 2019

Abstract
Post-translational modifications of the histone proteins play a key role in regulating processes that require access to DNA. Specifically, methylation of lysine 27 on histone 3 (H3K27) is intimately linked with transcriptional repression. EZH2, a histone lysine methyl transferase is the catalytic component of the PRC2 complex, which catalyzes H3K27 methylation. EZH2 dysregulation has been observed in different malignancies and inhibition of its catalytic activity has emerged as a novel therapeutic approach to treat human cancers. Potent, selective and reversible EZH2 small molecule inhibitors are currently being tested in Ph. 1 clinical trials. We and others have reported EZH2 dependencies across non-Hodgkin Lymphoma subtypes in cancer cell lines, in xenograft mouse models and in lymphoma patients.
We identified Multiple Myeloma as potential clinical application for EZH2 inhibitors. Treatment with EZH2 inhibitors such as CPI-360, CPI-169 and CPI-1205 cause apoptosis in multiple myeloma and plasmacytoma cell models and causes tumor growth inhibition in myeloma xenograft models at well tolerated doses. An EZH2-controlled transcriptional signature across various multiple myeloma was identified using integrated RNA-sequencing and ChIP-sequencing data. Combination studies testing EZH2 inhibitors with standard of care (SOC) agents across a panel of multiple myeloma cell lines showed synergistic responses with several of the SOC agents in vitro and in vivo.

Disclosures
Arora: Constellation Pharmaceuticals: Employment, Equity Ownership. Williamson:Constellation Pharmaceuticals: Employment, Equity Ownership. Apte:Constellation Pharmaceuticals: Employment, Equity Ownership. Balachander:Constellation Pharmaceuticals: Employment, Equity Ownership. Busby:Constellation Pharmaceuticals: Employment, Equity Ownership. Hatton:Constellation Pharmaceuticals: Employment, Equity Ownership. Bryant:Constellation Pharmaceuticals: Employment, Equity Ownership. Trojer:Constellation Pharmaceuticals: Employment, Equity Ownership.