bluuebunny/crossref_metadata_2025_split huggingface dataset:
GFI1b As a Novel Oncosuppressor in AML
Authors: Thivakaran Aniththa , Botezatu Lacramioara , Hoenes Judith Maria , Al-Matary Yahya Saleh , Olberding Nadine , Schütte Judith , Köster Renata , Opalka Bertram , Dührsen Ulrich , Khandanpour Cyrus 
Published: October 2019

Abstract
The proper differentiation of hematopoietic stem cells (HSCs) is regulated by a concert of different so called transcription factors (TFs). A disturbed function of these TFs can be the basis of malignant diseases such as acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Growth Factor Independence 1b (Gfi1b) is a repressing transcription factor, with a key role in maintaining the quiescence of HSCs and the proper emergence and maturation of erythrocytes and platelets. Here we show that low expression of GFI1B in blast cells is associated with an inferior prognosis of AML and MDS patients. Using three different mice models of human AML (Nup98-HoxD13, MLL-AF9 and expression of a mutated K-Ras), we could show that reduced expression of Gfi1b accelerates AML development in mice and the latency is even more shortened when Gfi1b is conditionally deleted. Using a limiting dilution assay of transplantation of different number of Gfi1b-wildtype and Gfi1b-deficient cells, we could show that loss of Gfi1b significantly enhanced stemness of leukemic cells. Since Gfii1b is involved in epigenetic regulation of gene expression, we analyzed effect of loss of Gfi1b on an epigenetic level by analyzing the whole genome using Chip-Seq. We found that loss of Gfi1b leads to genome wide increased level of H3K9 acetylation of genes and hence expression of these genes involved in leukemia development. On a molecular level, we found that loss of Gfi1b not only increases the levels of reactive oxygen species (ROS), but also induces gene expression changes of key AML-pathways such as the p38/ AKT pathways. These results demonstrate that Gfi1b functions as an oncosuppressor in MDS/AML development.

Disclosures
Dührsen: Roche: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding. Khandanpour:Max-Eder: Research Funding; Hospital of Essen university: Research Funding.
Ribosomal Protein L22 Loss Predisposes Stem Cells to Transformation By Altering Metabolism
Authors: Harris Bryan , Fahl Shawn , Perrigoue Jaqueline , Sykes Stephen M. , Verma Amit , Wiest David L 
Published: October 2019

Abstract
While mutations in ribosomal proteins (RP) have long been associated with increased cancer risk, the molecular basis for this association remains unclear. The prevailing view is that mutations in RP increase cancer risk either by impairing the biogenesis or function of the ribosome. Here, we report that loss of the RP, Rpl22, is frequently observed in human myelodysplastic syndrome (MDS) and is associated with reduced survival in acute myelogenous leukemia (AML). The link between Rpl22 loss and aggressiveness of myeloid disease is causal, since it is replicated in mice lacking Rpl22. Importantly, the development of an MDS-like syndrome in Rpl22-deficient mice and the accelerated development of myeloid leukemia are not caused by reduced protein synthesis in hematopoietic stem cells (HSC). Instead, whole transcriptome analysis of HSC reveals that Rpl22 loss alters the expression of genes controlling cell metabolism and results in an increase in fatty acid oxidation. Moreover, the increased fatty acid oxidation is required for the increased self-renewal and reduced differentiation displayed by Rpl22-deficient HSC, as well as the survival of Rpl22-deficient myeloid leukemia cells. Together, these findings indicate that RP are capable of suppressing transformation potential in ways that do not involve effects on global protein synthesis. Indeed, Rpl22 suppresses transformation by suppressing lipid oxidation, suggesting that MDS and AML patients with reduced Rpl22 expression might benefit from pharmacologic interventions targeting lipid oxidation.

Disclosures
No relevant conflicts of interest to declare.
Identifying Mechanisms of Glucocorticoid Resistance in Relapsed Pediatric T-ALL
Authors: Roderick Justine E. , Gallagher Kayleigh M , Tang Katherine M , Kugler-Umana Olivia , Zhu Lihua J , Green Michael R , Kelliher Michelle 
Published: October 2019

Abstract
While great strides have been made in the improvement of outcome for newly diagnosed pediatric acute lymphoblastic leukemia (ALL) patients, prognosis for relapsed leukemia patients remains poor. The synthetic glucocorticoid (GC) dexamethasone is part of the standard treatment for pediatric ALL and patient response to glucocorticoid treatment has proved to be a reliable prognostic indicator. Identifying the biological pathways responsible for glucocorticoid resistance may reveal novel therapeutic targets to prevent and treat relapsed ALL. Although genomic analyses of relapsed patients and matched diagnosis-relapse patient pairs have begun to define the genomic landscape of relapsed disease, discerning "driver from passenger" genetic lesions remains challenging. To identify glucocorticoid resistance genes in an unbiased, high-throughput manner, we conducted a genome wide, survival based, shRNA screen in dexamethasone sensitive murine T-ALL cells. Our preliminary data identify several hundred genes capable of mediating GC resistance, including several known GC resistance genes Nr3c1, Rcan1, Btg1 and Mllt10, thereby validating our experimental approach. Candidate genes identified in the screen including EP300 (p300), GATA3 and IKZF1 are known leukemia suppressors in pediatric ALL and the EP300 paralog CREBBP and IKAROS have been linked to GC resistance, indicating that suppressor genes involved in human leukemia and GC resistance are identified in our mouse screen. Consistently, we found the expression of several screen hits significantly decreased and/or mutated in relapse patient samples. Novel dexamethasone resistance genes identified in the screen interfere with GC-induced transcription (Stat3, Ikzf1), promote pluripotency (Esrrb, Sox2) or stimulate cAMP signaling (Adcy3, Gnas, Creb1). Silencing of these genes in multiple mouse T-ALL cell lines has no detectable effects on leukemic growth/survival in vitro, but confers resistance to dexamethasone treatment in vitro and in vivo. Moreover, we show that silencing of some candidate dexamethasone resistance genes accelerates leukemogenesis in vivo, demonstrating that leukemia suppressor genes were identified. Effect(s) of silencing or inhibiting these novel dexamethasone resistance genes/pathways in human T-ALL cell lines, primary patient samples and xenografts will be discussed. We predict that targeting these dexamethasone resistance pathways may re-sensitize relapse pediatric T-ALL cells to dexamethasone and/or contribute to more effective patient stratification to prevent relapse and induction failure.

Disclosures
No relevant conflicts of interest to declare.
MYC-Dependent PI3K and MCL-1 Feedbacks Attenuate BET Inhibitors Activity in Diffuse Large B-Cell Lymphoma
Authors: Derenzini Enrico , Mondello Patrizia , Liu Yuxuan , Scallion Mary , Asgari Zahra , Philip John , Hilden Patrick , Djaballah Hakim , Ouerfelli Ouathek , de Stanchina Elisa , Seshan Venkatraman , Hendrickson Ronald , Zelenetz Andrew D. , Younes Anas 
Published: October 2019

Abstract
MYC overexpression is a poor prognostic predictor in Diffuse Large B-Cell Lymphoma (DLBCL). MYC-targeting with bromodomain and extraterminal protein family (BET) inhibitors is a promising strategy for the treatment of MYC-driven cancers, including lymphomas. However, preclinical and emerging data from early clinical trials demonstrated a modest antiproliferative activity in vitro and in vivo. We hypothesized that BET inhibition may induce feedback survival mechanisms preventing or attenuating cell death that could be exploited for designing future, more effective, combination strategies. In a high-throughput combinatorial drug screening experiment, we found that phosphatidylinositol 3-kinase (PI3K) pathway inhibitors enhanced the antiproliferative effects of BET inhibitors (JQ1, I-BET 151, CPI-203) with a strong class effect. JQ1 upregulated the mRNA expression of several upstream components of the PI3K pathway, including PIK3CA, PIK3R1, PDK1 in a large panel of DLBCL and Burkitt lymphoma cell lines. These effects translated in increased pathway activation as demonstrated by increased levels of the phosphorylated forms of downstream targets GSK3α/β, TSC2, P70S6K, and by increased concentrations of chemokines known to be regulated by PI3K in cell culture supernatants (CCL3 and CCL4). This effect was reversed by submicromolar doses of the PI3K inhibitor BKM-120. MYC silencing recapitulated the effects of BET inhibitors on PI3K pathway gene expression, activation and chemokine secretion. These data indicate that BET inhibition induces PI3K activation by a MYC-dependent feedback. We also observed transcriptional upregulation of the antiapoptotic gene Myeloid Leukemia 1 (MCL-1) following BET inhibition or MYC depletion, suggesting a second MYC-dependent mechanism. RNAi-mediated MCL-1 silencing or co-treatment with a small molecule MCL-1 inhibitor (UMI-77) enhanced the effects of BET inhibitors in DLBCL cell lines by inducing apoptosis. Using SILAC-based quantitative mass spectrometry, we found that BET inhibitors at submicromolar doses downregulated several E2 ubiquitin conjugating enzymes including UBE2C. RNAi mediated UBE2C knockdown induced MCL-1 upregulation in DLBCL cells. The enhanced in vitro effect of combining BETi and PI3Ki was reproduced in TMD8 mouse xenografts. To our knowledge, this is the first study demonstrating MYC-dependent regulation of the PI3K pathway, MCL-1 and the ubiquitin system upon BET inhibition. Our study revealed previously unknown mechanisms of action of BET inhibitors uncovering novel MYC-dependent survival feedback loops, and providing a framework for future combination strategies.

Disclosures
Zelenetz: Gilead Sciences: Research Funding.
Survival Outcomes in Grade 3 Follicular Lymphoma Prior to and after the Introduction of Rituximab - an Analysis Based on the Surveillance, Epidemiology, and End Result Registry Database
Authors: Giri Upama , Martin Michael G. 
Published: October 2019

Abstract
Background
Follicular lymphoma (FL) is the most common form of indolent lymphoma, however Grade 3 FL (FL3) has more aggressive behavior and its response to therapy is controversial. Several studies have reported improved clinical outcomes in patients with FL3 treated with rituximab (R), approved in early 2006, as a first line therapy for diffuse large B-cell lymphoma. The aim of this population based study is to compare the overall survival and disease specific survival in patients diagnosed with FL3 prior to and after 2006.
Materials and methods
We used the Surveillance, Epidemiology, and End Results 18 database to identify cases diagnosed with FL3 between 1983 and 2013, limiting the selection to patients aged more than 15 years with single primary malignancy. The data was split into two cohorts - Cohort 1 comprised of cases diagnosed between 1983 and 2005, with a study cutoff of December 2005, and Cohort 2 comprised of cases diagnosed between 2006 and 2013. The Overall Survival (OS) and Disease Specific Survival (DSS) for the two cohorts were calculated using the Kaplan-Meier method and the results were compared using the Log Rank test. The Cox proportional hazards regression model was used to identify factors other than time of diagnosis, which had a significant impact on survival times.
Results
Cohort 1 included 3,959 cases with death occurring in 1,319 cases during the study period (1,013 deaths due to disease specific factors) and Cohort 2 included 3,050 cases with death occurring in 509 cases (374 deaths due to disease specific factors) (table 1). The 5-year OS and DSS survivals for Cohort 1 were 59.3% and 67.7%, and for Cohort 2 were 78.3% and 84% respectively (figure 1). The differences in both OS and DSS survival rates were confirmed to be significant using the Log Rank test (p<<0.005 in both instances).
Cox regression analysis was performed using age at diagnosis, sex, race, marital status, primary site (nodal/extra nodal) and Ann Arbor stage as covariates, after removing cases with missing values. The test results showed that age at diagnosis, sex, Ann Arbor stage (p<<0.005 for all three) and primary site (p<0.05) had a significant impact on OS. However, DSS was not significantly influenced by primary site. Males had an increased risk of mortality, as did an increase in age and advanced Ann Arbor stage (table 2).
Conclusion
A significant increase in OS and DSS was observed in patients diagnosed with FL3 after the introduction of rituximab. Survival outcomes were also influenced by age at diagnosis, sex and Ann Arbor stage.
Figure Figure.

Disclosures
No relevant conflicts of interest to declare.
Post-Transplant Lymphoproliferative Disorders in Transplant Recipients: 14-Yr Experience at the Hospital Israelita Albert Einstein - Brazil
Authors: Blumenschein Danielle Isadora , da Rocha Juliana Dall Agnol , Perini Guilherme Fleury , Esteves Iracema , Bezerra Alanna Marra P. S. , Pasqualin Denise da Cunha , Ribeiro Andreza Alice Feitosa , Santos Fabio Pires de Souza , Hamerschlak Nelson , Helman Ricardo 
Published: October 2019

Abstract
Introduction: The number of patients who have undergone organ and bone marrow transplantation continues to increase, as does long-term survival. Post-transplant lymphoproliferative disorders (PTLD) are potentially life-threatening complications after solid organ transplantation. Epstein-Barr virus (EBV) infection that leads to uncontrolled B cell proliferation and tumor formation. PTLD is relatively common malignancy after transplantation and is seen up to 10% of all solid organ transplant recipients, and varies considerably among the different types of organs transplanted. We sought to determine incidence and mortality risk of PTLD in recipients of Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
Patient and Methods: We conducted a retrospective observational study of 3006 recipients of lung, kidney, liver, pancreas, heart and bone marrow between 2002 and 2015. A total of 26 cases (0.8%) of PTLD were identified in 3006 transplants. Kaplan-Meier analysis was performed for PTLD patient survival after PTLD.
Results: Median interval from transplantation to diagnosis was 49 (4-150) months. Median age was 49 years (12-73) and 73% were men. Histological subgroups included: Monomorphic PTLD (50%), Hodgkin Lymphoma (11,5%), Burkitt (15,3%), Anaplastyc large cell (7,6%) and Plasmacytic Hyperplasia (15,3%). Sixteen patients (61,5%) were EBV (+) and eleven (42,3%) were IPI III-IV only two had bone marrow infiltration. Treatment of PTLD varied according to stage and clinical circumstances: six patients (23%) were treated with Rituximab only and seventeen (65,3%) treated with R-chemotherapy. Nine (34,6%) patients died. Changing immunosuppression (IS) from calcineurin inhibitor to sirolimus at the time of diagnosis may have improved survival, since 5 patients remain alive. The median overall survival was 1260 days, and 2-years overall survival was 65,4%.
Conclusion: PTLD after solid organs transplantation remains a challenge as a result of its frequency, complexity and disappointing outcome. We found a paucity of early onset PTLD in our cohort with only one case in the first posttransplant year. Potential contributing factors included a high prevalence of previous EBV virus exposure. The rate of PTLD malignancies in our group is comparable to that reported in other centers in Europe and North American, since it is the largest series reported by a single institution in South America. Consistent with the known antiproliferative effect of sirolimus, switching IS from calcineurin inhibitor to sirolimus may improve survival.

Disclosures
No relevant conflicts of interest to declare.
NKG2D Gene Polymorphism Is Associated with Disease Control of Chronic Myeloid Leukemia By Dasatinib
Authors: Hara Ryujiro , Onizuka Makoto , Matsusita Erika , Kikkawa Eri , Nakamura Yoshihiko , Ogiya Daisuke , Murayama Hiromichi , Omachi Ken , Shirasugi Yukari , Ogawa Yoshiaki , Kawada Hiroshi , Ando Kiyoshi 
Published: October 2019

Abstract
Dasatinib (DA) is a tyrosine kinase inhibitor (TKI), and is approved for the treatment of naïve and relapsed/refractory Philadelphia chromosome positive leukemia. DA is a potent and multi-target TKI, and a part of patients treated with DA are reported to exhibit lymphocytosis and that is caused by a proliferation of NK cells or CD8 T cells. Nowadays, a lot of reports about the stop TKI trials suggested that treatment free remission of the CML after TKI discontinuation was significantly associated with NK cell proliferation in peripheral blood of the patients. So far, little is known about the individual differences in NK cell response among patients treated with Dasatinib.
NKG2D is an activating receptor expressed on NK cells. Recently, functional SNP were identified between LNK1 and HNK1 haplotypes of the NKG2D gene. We analyzed the association between patient's NKG2D polymorphism and achievement of the deep molecular response by Dasatinib. We retrospectively investigated thirty-one patients who were treated with Dasatinib for the first-line treatment of CML at Tokai university school of medicine between 2011 and 2015. Patients with HNK1 haplotype tended to achieve MR4.5 more frequently (not significant), and these patients accomplished MR4.5significantly faster than others.
Next, we harvested NK cells from healthy volunteers, and investigated NK cell responses by Dasatinib in vitro. There were differences in the degree of NK cell proliferation capacity among subjects after DA treatment in vitro. We found that NK cells with NKG2D LNK1/LNK1 haplotype exhibited significantly lower proliferation capacity than others in the population. NK cells of higher proliferation capacity exhibited Vav-1 Tyr174 phosphorylation, but they didn't show any differences in cytotoxicity capacity.
In this study, our data suggest that DA may stimulate NK cells with NKG2D HNK1 haplotype more strongly than LNK1 haplotype, and therefore patients with HNK1 haplotype can achieve deep molecular response faster than others. So, personalized medicine according to their NKG2D haplotype may be useful to the treatment of CML, especially when they are considered to discontinue DA in stop TKI trials.

Disclosures
No relevant conflicts of interest to declare.
A Potent Small Molecule Compound Might Overcome High Level Drug Resistant Mutations of Bcr-Abl1
Authors: Wang Feng-Juan , Niu Ting 
Published: October 2019

Abstract
Objective: The third-generation tyrosine kinase inhibitor (TKI) ponatinib can overcome many kinds of single mutations including T315I of Bcr-Abl1. Unfortunately, recent clinical studies have identified some new point mutations resistant to ponatinib and the other marketed TKIs. These mutations include compound mutations or T315M single mutation, which we called high level drug resistant mutations in this study. Therefore, it is an urgent task to find a potent small molecule inhibitors, which can overcome these high level drug resistant mutations.
Methods: To screen for compounds that can overcome the high level drug resistant mutations of Bcr-Abl1, we firstly established genetic engineering cell models using the Ba/F3 cell line, including: (1) Ba/F3-Bcr-Abl1T315M; (2) Ba/F3-Bcr-Abl1T315I/E255V; (3) Ba/F3-Bcr-Abl1E255V/Y253H. The established cell lines were also carefully verified .Then we used these established cell models and others we have already obtained, including Ba/F3-Bcr-Abl1WT, Ba/F3-Bcr-Abl1T315I, and Ba/F3-Bcr- Abl1E255V, to screen an in-house chemical library. The most potent compound SKLB-518 was finally chosen to perform further studies both in vitro (cell and protein level) and in vivo (allograft subcutaneous cancer mice model).
Results: In vitro assays, three marketed TKIs, namely imatinib, dasatinib, and ponatinib, were chosen as the references. The IC50 value of SKLB-518 to inhibit Ba/F3-Bcr-Abl1E255V/Y254H cells was 0.033 μM, which was more active by >100 times and 6.14 times than that of imatinib (IC50: >10 μM) and ponatinib (IC50:0.201μM), respectively, and comparable with dasatinib (IC50:0.028 μM). The IC50 of SKLB-518 to inhibit Ba/F3- Bcr-Abl1T315I/E255V cells was 0.094 μM, which was more potent by >100 times, 30~100 times, and 8.69 times than that of imatinib (IC50: >10 μM), dasatinib (IC50: 3~10 μM), and ponatinib (IC50: 0.817 μM), respectively. In vivo, thedata indicated that SKLB-518 could significantly inhibit tumor proliferation at the doses of 30 mg/kg/d and 45 mg/kg/d (%T/C was 62.1 and 72.5, respectively; both groups p<0.001), while ponatinib couldn't inhibit tumor growth at the 30 mg/kg/day dose (%T/C was 87.8, p=0.157). Immunohistochemical staining assays indicated that SKLB-518 at the doses of 45 mg/kg/d could potently inhibit Bcr-Abl1 downstream targets (Crkl and Stat5). Meanwhile, we didn't find severe toxicity of SKLB-518 in the effective doses both in cells and in mice.
Conclusion:Independently developed small molecule SKLB- 518 might overcome the high level drug resistant mutations of Bcr-Abl1.

Disclosures
No relevant conflicts of interest to declare.