bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lig4 R278H Mutation Impacts on LT-HSC Functions, Cancer Development and Aging
Authors: Yan Catherine T. , Park Ji hye , Muniandy Parames , Troppito Logan , Welner Robert 
Published: October 2019

Abstract
Abstract 1350
DNA Ligase IV (Lig4) is an essential component of the non-homologous end-joining (NHEJ) repair pathway, essential for the end-ligation of broken DNA ends generated during V(D)J recombination and IgH Class Switch Recombination (CSR) in B lymphocytes. Mutations in Lig4 underlie the DNA Lig4 Syndrome, a rare herited immunodeficiency disease. We have modeled one such mutation in mice, a homozygous arginine to histidine 278 (R278H) change with the enzyme active site, which others and we have shown significantly impairs the catalytic end-ligation activity of the LigIV protein. These mice show significant immune-specific defects, including decreased T and B lymphocytes, in part associated with defects in development, increased cell death, and/or autophagy. Bypass of B lymphocyte development leads to increased numbers of total peripheral B lymphocytes that can undergo robust CSR at near normal levels, which however contain high levels of IgH specific DNA breaks and translocations. Both young and older mice display significant reduction in LT-HSCs, which may underlie their B and T lymphocyte associated defects, which in LT-HSC reconstitution experiments in SCID mice, fail to engraft. The decreased R278H mice LT-HSCs observed are in contrast to previous reported findings for Ku80 and DNA-PKcs deficient mice, and also ATM deficiency, which we further are investigating to elucidate the normal and pathological functions of aberrant Lig4. We hypothesize the cause of the LT-HSC defects to be caused by changes in DNA damage, cell cycle checkpoint responses and genomic stability maintenance associated with the R278H mutation, that promote the restriction or selection of LT-HSC cell populations that are prone to genomic instability during differentiation. As such, the majority of relatively, young adult R278H mice routinely spontaneously develop T cell lymphomas, and mice that do not succumb to lymphomas subsequently go on to develop other solid tumors and other pathological consequences which are characteristic of premature aging. Our findings implicate Lig4 is required for genomic stability maintenance and proliferative expansion of earliest HSCs and other stem cell populations. The implications of our findings in the context of impacts of the R278H mutation on genomic instability and DNA damage response in the context of HSCs, cancer development and aging in the DNA Lig4 Syndrome, and its relation to other human immunodeficiency and progeroid syndromes will be discussed.

Disclosures:
No relevant conflicts of interest to declare.
Signal Transducer and Activator of Transcription 3 Promotes Leukemogenesis
Authors: Ghoshal Sampa , Brady Michael T , Ustwani Omar , Tracy Erin , Den Haese Jason , Wallace Paul K. , Baumann Heinz , Wetzler Meir 
Published: October 2019

Abstract
Abstract 1395
We have previously shown that constitutive activation of the signal transducer and activator of transcription (STAT) 3 protein is associated with worse outcome in patients with acute myeloid leukemia (AML). To clarify the role of STAT3 signaling in AML leukemogenesis, STAT3 shRNAmirs were introduced into the AML cell line HEL that carries the Janus kinase 2 with V617F mutation leading to constitutive tyrosine phosphorylation and activation of STAT3 and STAT5. Clonal line of HEL cells expressing STAT3 shRNAmir or control shRNA were generated and then transduced with a lentiviral virus harboring a constitutively expressed firefly luciferase gene. Engraftment of these cells was evaluated in a disseminated xenograft non-obese diabetic severe immunocompromised mouse model. When tested in vitro, HEL STAT3 knock-down (HEL-STAT3KD) cells showed normal STAT5 expression and activity but had lower proliferation rates than control cells, PKC-bII and Pim1 were down-regulated, and activation of ERK1/2 was increased. Trans-signaling by hyper-IL-6 enhanced STAT3 phosphorylation proportional to STAT3 level. In vivo imaging of luciferase activity demonstrated significant delay in engraftment of STAT3KD cells compared with controls (Figure). To the best of our knowledge, this is the first demonstration that STAT3 knockdown delays leukemia cell engraftment, that STAT3 signaling is crucial for AML leukemogenesis and should promote STAT3-tailored therapeutic targeting.Figure:Down-regulating STAT3 results in delayed HEL engraftment. Panel 1A, Optical CCD images of HEL (non-silenced control in the upper panel and shRNAmir in the lower panel) xenografts in NOD/SCID mice from day 28 and day 45. Panel 1B, Graphs showing correlation of luciferase gene expression in HEL xenografts (p=0.0079, Man-Whitney test). The graphs were generated from repeated scanning of the mice on days 14, 28, 35, 45, 53 and 72. Individual mean values (photons/s/cm2/sr) calculated from the regions of interest were plotted.Figure:. Down-regulating STAT3 results in delayed HEL engraftment. Panel 1A, Optical CCD images of HEL (non-silenced control in the upper panel and shRNAmir in the lower panel) xenografts in NOD/SCID mice from day 28 and day 45. Panel 1B, Graphs showing correlation of luciferase gene expression in HEL xenografts (p=0.0079, Man-Whitney test). The graphs were generated from repeated scanning of the mice on days 14, 28, 35, 45, 53 and 72. Individual mean values (photons/s/cm2/sr) calculated from the regions of interest were plotted.

Disclosures:
No relevant conflicts of interest to declare.
CCDC26 Polymorphisms Are Differentially Expressed in Myeloid Malignancies with Mutant IDH1 Compared to Their IDH2R140-Mutated or IDH-Unmutated Counterparts
Authors: Lasho Terra L , Tefferi Ayalew , Pardanani Animesh , Finke Christy , Fink Stephanie R , Decker Paul A , Jenkins Robert 
Published: October 2019

Abstract
Abstract 2807
CCDC26 is a retinoic acid-dependent modulator of myeloid cell differentiation and death (Yin W et al. Oncogene 2006 :25 :3735). CCDC26 maps to chromosome 8q24.21 and germline polymorphisms in the gene have been associated with low-grade gliomas (Jenkins RB et al. Cancer Genetics 2011;204 :13), which in turn have recently been shown to frequently express IDH1 mutations (Parsons D et al, Science 2008;321 :1807). More recently, we have discovered that CCDC26 SNP associations in gliomas are primarily restricted to patients with IDH1 mutations (Jenkins et al. unpublished observations). We therefore hypothesized that germline CCDC26 SNPS might be associated with patients with myeloid malignancies that harbor IDH1 mutations (Mardis et al. NEJM 2009;361 :1058). Seventy-two IDH -mutated patients with chronic or blast phase myeloproliferative neoplasms (MPN), myelodysplastic syndromes or acute myeloid leukemia (most constituting post-MPN events) were identified: 18 IDH1 R132, one IDH2 R172 and 53 IDH2 R140. These 72 patients and a control group of 153 IDH unmutated cases with myeloproliferative or myelodysplastic neoplasms (total n =225) were genotyped for CCDC26 risk alleles associated with IDH -mutated gliomas: rs10464870, rs891835 and rs4295627. The respective minor allele frequencies (MAF) were significantly different between IDH1 (11%, 8% and 6%) and IDH2 (30%, 27% and 24%) mutated cases (p=0.037, 0.040 and 0.021; OR 3.4, 3.7 and 6.1 with 95% CI of 1.1–10.5, 1.1–13.0 and 1.3–28.9) as well as between IDH- wild type (24%, 24% and 21%) and IDH1 -mutated (11%, 8% and 6%) cases (p=0.10, 0.043 and 0.035; OR 0.42, 0.29 and 0.21 with 95% CI of 0.15–1.19, 0.09–0.96 and 0.05–0.90). The MAF values in our IDH -unmutated cases were similar to that of population-based controls. However, the direction of SNP associations in IDH1 -mutated myeloid malignancies were opposite of those seen in IDH1 -mutated gliomas. Our observations suggest a differential effect of CCDC26 genetic polymorphisms in IDH1 -mutated myeloid malignancies compared to either their IDH2 R140-mutated or IDH1 -mutated gliomas. Such differences in genomic context might contribute to hitherto seen differences in prognostic impact between IDH2 R140 vs. IDH1 R132 vs. IDH2 R172, in AML (Green CL et al. Blood Published online before print May 19, 2011, doi: 10.1182/blood-2010-12-322479).

Disclosures:
No relevant conflicts of interest to declare.
Dicer Plays An Important Role in the Progression and Prognosis of Chronic Lymphocytic Leukemia
Authors: Xu Wei , Zhu Dan-Xia , Fan Lei , Fang Cheng , Zou Zhi-Jian , Wang Yin-Hua , Li Jian-Yong 
Published: October 2019

Abstract
Abstract 2848
Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Alterations in microRNAs (miRNAs) expression have been proposed to play role in CLL pathogenesis. However, the reasons of miRNAs expression alterations observed in CLL have not been elucidated, one possible explanation suggested is deterioration of miRNA biogenesis machinery involves Dicer and Drosha. Dicer and Drosha are main regulators of miRNA biogenesis, and deregulation of their expressions have been observed in various cancers including breast cancer, ovarian cancer, prostate cancer, neuroblastoma tumors, et al. To investigate the role of Dicer and Drosha in CLL, we assessed the expression of Dicer and Drosha and their correlation with other prognostic factors, including Binet stages, immunoglobulin heavy chain variable gene (IGHV) mutation status, TP53 mutation status, ZAP-70 protein and CD38 expression level in 165 CLL patients by using real-time PCR methods. We found that Dicer expression was significantly higher in patients of Binet B and C stage compared with Binet A stage (mean ± SD, 0.017 ± 0.010 vs. 0.015 ± 0.019; p =0.001). Patients with unmutated IGHV genes had significant lower expression of dicer than patients with IGHV mutations (mean ± SD, 0.012± 0.006 vs 0.019± 0.013, p <0.0001). The lower expression level of Dicer was also significantly associated with higher level of CD38 and ZAP-70 (p =0.0304 and p =0.0075, respectively). We also analyzed Dicer expression in different cytogenetic subgroups. Lower Dicer level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22.3) in contrast to higher level in good risk cytogenetics (deletion in 13q14 as the sole abnormality). Furthermore, the lower expression of Dicer in CLL shows a strong association with shorter overall survival (OS) (132 months vs. not reached, p =0.0046) as well as with reduced treatment free survival (TFS) (24 months vs.110 months, p =0.0006). By contrast, no differences in the expression of Drosha among these groups of patients were observed. Our data have been able to demonstrate for the first time that Dicer expression may play an important role in the progression and prognosis of CLL.

Disclosures:
No relevant conflicts of interest to declare.
Adoptively Transferred Central Memory Derived Human CD8+Effectors Exhibit Superior Engraftment Fitness Over Their Naïve T Cell Derived Counterparts
Authors: Wang Xiuli , Wong ChingLam W , Aguilar Brenda , Chang Wen-Chung , Ostberg Julie R , Riddell Stanley R. , Forman Stephen J. , Jensen Michael C. 
Published: October 2019

Abstract
Abstract 2982
In clinical trials of adoptive T cell therapy, the persistence of transferred cells correlates with therapeutic efficacy. The engraftment fitness of ex vivo propagated T cells is in part pre-determined by the differentiation status of precursor T cells from which effector cell products are derived. In peripheral blood, T cells are comprised of three major subsets- naïve, central memory (Tcm) and effector memory (Tem), each having distinct phenotypic and functional attributes. We have previously shown that human CD8+ effector cells derived from Tcm were superior to Tem in their ability to engraft and persist following adoptive transfer (Wang, X. 2011). In this study, we set out to compare the engraftment fitness of CD8+ effector cells derived from naïve precursors with that of Tcm-derived effectors. FACS sorted CD8+ CD45RA+CD62L+ naïve (Tn) and CD8+CD45RO+CD62L+ Tcm cells from healthy donors were expanded in vitro for 14 days in the presence of OKT3, feeder PBMC and IL-2 at 50U/mL. Despite the comparable levels of CD28 expression on unstimulated CD8+ Tn and CD8+Tcm (91±2% for CD8+Naive and 94±2% for CD8+Tcm), Tcm-derived effector T cells (CD8+TCM/E) displayed significantly higher levels of CD28 expression with corresponding high levels of cytoplasmic phosphorylated-AKT as compared to Tn-derived cells (CD8+TN/E) (47±5% for CD8+TN/E vs. 83±4% for CD8+ TCM/E). After the initial 14 days of in vitro expansion, CD8+TCM/E were able to persist in vitro for more than 50 days in the presence of gamma-c cytokines (IL-2 50/ml or IL-15 10ng/ml) while CD8+TN/E failed to survive in either condition, which is consistent with the observed higher expression levels of IL-15R α and IL-2R β by CD8+TCM/E. After engraftment in huIL-15 replete immunodeficient (NSG) mice, we observed that CD8+TCM/E exhibited higher levels engraftment and mounted more robust proliferative responses to in vivo challenge with immunostimulatory vaccines. In contrast to CD8+TN/E, engrafted CD8+TCM/E reaquired/sustained high frequency of cells expressing IL-7Ralpha. To re-direct T cell specificity against B-lymphoid malignancies, purified CD8+Tn and CD8+Tcm from healthy donors were engineered with lentiviral vector encoding CD19R-CD28-EGFRt-epHIV7. CD19-specific CD8+TCM/E persist after adoptive transfer into the human IL15 reconstituted NSG mice, whereas no engraftment was detected in the CD19-specific CD8+TN/E infused NSG mice. These studies using human T cells support the use of central memory derived effector cells for adoptive therapy of cancer and infectious disease.

Disclosures:
No relevant conflicts of interest to declare.
Whole Genome Sequencing Reveals a Widely Expressed Mutation (MYD88 L265P) with Oncogenic Activity in Waldenstrom's Macroglobulinemia
Authors: Treon Steven P , Xu Lian , Zhou Yangsheng , Liu Xia , Yang Guang , Cao Yang , Hanzis Christina , Sheehy Patricia , Manning Robert , Patterson Christopher J , Laramie Jason M , Skifter Donald A , Lincoln Stephen E , Hunter Zachary 
Published: October 2019

Abstract
Abstract 300
We performed whole genome sequencing (WGS) of lymphoplasmacytic cells from 30 Waldenstrom's Macroglobulinemia (WM) patients, with paired normal tissue sequencing for 10 patients. Tumor and normal genomes were both sequenced to an average of 66X coverage of mapped individual reads. A recurring sequence variant at position 38182641 in chromosome 3p22.2 was identified which resulted in a single nucleotide change from T®C in the myeloid differentiation primary response (MYD88) gene, and a predicted non-synonymous change at amino acid position 265 from leucine to proline (L265P). This variant was the most common of a median of 3,419 (range 2,540–4,011) somatic variants identified by WGS in paired patients, and was present in tumor cells from all 10 paired patients, and 16 of 20 unpaired patients. For 22 of 26 patients, the MYD88 L265P variant was heterozygous, whereas in 4 patients an acquired UPD event at 3p22.2 resulted in homozygous presence of the variant in at least a subset of tumor cells. Sanger sequencing confirmed the presence of the MYD88 L265P variant in all 26 patient tumor samples revealed by WGS, as well as in one additional patient's tumor sample that was not identified by the variant calling algorithms but for whom 12% of the WGS read level mappings showed the MYD88 L265P variant. In contrast, the MYD88 L265P variant was absent in normal paired tissues. Sanger sequencing therefore confirmed the somatic presence of the MYD88 L265P variant in tumor cells from 27 of 30 (90%) WM patients, and also identified this variant in BCWM.1 and MWCL-1 WM cells. In contrast, the MYD88 L265P variant was absent in CD138+ selected tumor cells from 8 of 8 multiple myeloma (MM) patients, and CD19+ cells from 12 of 12 healthy individuals, as well as in 7 of 8 patients with IgM monoclonal gammopathy of unknown significance (MGUS), in whom absence of the MYD88 L265P variant was further confirmed by TA cloning and sequencing of at least 100 clones. In the sole IgM MGUS patient in whom the MYD88 L265P mutation was detected, subsequent disease evolution occurred. Importantly, knock-down of MYD88 expression by lentiviral transduction led to loss of NF-κβ signaling and apoptosis of both BCWM.1 and MWCL-1 WM cells, with enhanced survival observed by complementary transduction with MYD88 L265P versus MYD88 wild type. The results of these studies therefore demonstrate a widely expressed somatic variant (MYD88 L265P) in malignant LPC of WM, whose presence confers oncogenic activity, and which may help distinguish WM disease from IgM MGUS or MM.

Disclosures:
No relevant conflicts of interest to declare.
A Sequence Variation in the Promoter Region of PTPN22 Gene Predicts Relapse After HLA-Fully-Matched Unrelated Bone Marrow Transplantation for Hematologic Malignancies
Authors: Espinoza Luis J. , Takami Akiyoshi , Nakata Katsuya , Onizuka Makoto , Morishima Yasuo , Fukuda Takahiro , Kodera Yoshihisa , Nakao Shinji 
Published: October 2019

Abstract
Abstract 3088
The protein tyrosine phosphatase non-receptor 22 (PTPN22), also known as LYP, is an intracellular phosphatase ubiquitously expressed with particularly high expression in hematopoietic tissues that is a critical negative regulator of signaling through the T cell receptor and has emerged as the strongest common genetic risk factor for human autoimmunity outside the major histocompatibility complex. In this study we analyzed the impact of the polymorphism rs2488457 (1123G>C) in the promoter region of PTPN22 gene on transplant outcomes in patients undergoing unrelated HLA-matched bone marrow transplantation (BMT) through the Japan Donor Marrow Program. The PTPN22 rs2488457 genotypes were retrospectively analyzed in a cohort of 663 patients with hematologic malignancies and their unrelated donors. The presence of the C/C or C/G genotype in the donor side was associated with a significantly lower incidence of relapse compared to the donor G/G genotype (28% vs. 34% 5-years, P =0.05) (Fig.1). No difference was noted in transplant-related mortality, or graft-versus-host disease in relation to the rs2488457 polymorphism. The donor C/C or C/G genotype remained statistically significant for relapse in the multivariate analyses (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.43 to 0.85; P =0.004). These differences in relapse did not significantly affect on overall survival (OS) (48% vs. 49% 5-years, P =0.85). The recipient PTPN22 genotypes did not significantly influence the transplant outcomes. These results suggest an association of the donor C/C or C/G genotype with lower disease relapse. These could therefore be useful in selecting the donor and creating therapeutic strategies for improving the final outcome of allogeneic BMT.

Disclosures:
No relevant conflicts of interest to declare.
Comorbidities Influence Survival in Patients with Multiple Myeloma
Authors: Wildes Tanya , Vij Ravi , Colditz Graham A 
Published: October 2019

Abstract
Abstract 3142

Introduction:
Advancing age is associated with poorer prognosis in patients with multiple myeloma (MM). Comorbidities increase in prevalence with age, but the impact of comorbidities on survival in patients with MM is not known. The purpose of this study was to examine the impact of comorbidities on survival in multiple myeloma. Methods: All patients (pts) with MM diagnosed and treated at Washington University School of Medicine in St. Louis, Missouri from 1999–2010 were identified from the Barnes-Jewish Hospital Oncology Data Services Database. The institution's cancer registrars retrospectively collect clinical, demographic and survival data in accordance with the American College of Surgeons Commission on Cancer guidelines. Comorbidities are graded as None, Mild, Moderate or Severe using the ACE-27 comorbidity index [Piccirillo et al. J Reg Mgmt 1999]. Patients without data on comorbidities were excluded from the study. The primary endpoint was overall survival (OS), calculated from the date of diagnosis and censored at the time of last follow-up. OS was estimated using the Kaplan-Meier method, and compared between comorbidity groups using the Log-Rank test. The independent effects of age and comorbidities were evaluated using Cox Proportional Hazards Modeling. Results: 569 patients were identified in the database. Median age of patients was 59 years (range 33–91 years); 54.8% were male, 45.2% were female; 74.9% were white, 23.2% were black, and 1.9% were other races/ethnicities. Based on the ACE-27 comorbidity index, 181 pts (31.8%) had no comorbid medical conditions, 226 (39.7%) had mild comorbidities, 115 (20.2%) had moderate comorbidities, 47 (8.3%) had severe comorbidities. In the entire cohort, the median OS was 49.2 months [95% confidence intervals (CI) 42.9 – 55.6 months]. Survival by comorbidity category and age group are shown in table 1. The differences in survival between comorbidity groups in each age group and the entire cohort were statistically significant (log-rank p<0.001). Severe comorbidities were associated with a significantly increased risk of death after controlling for age (HR 1.97, P=0.002). Conclusion: The presence and severity of comorbidities confer a poorer prognosis in patients with MM. Further study is needed to determine to what extent comorbidities directly impact survival versus impacting therapeutic decision-making and tolerance of therapy.

Disclosures:
Vij: Celgene: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau.