bluuebunny/crossref_metadata_2025_split huggingface dataset:
PTEN Expression Is Decreased in Pediatric Burkitt Lymphoma Tissues but Does Not Correlate with AKT Activation.
Authors: Vladimir Rodic , Sheryl Tripp , Bayerl Michael G , Barnette Phillip , Schiffman Joshua D. , Perkins Sherrie L. , Miles Rodney R. 
Published: October 2019

Abstract
Abstract 2664

Background:
We have recently shown that a subset of pediatric Burkitt lymphoma (pBL) show gain of 13q31, containing the microRNA (miRNA) MIR-17–92 locus, as well as associated increased expression of miRNA from that locus. PTEN, a tumor suppressor phosphatase that negatively regulates the PI3K/AKT/mTOR pro-survival pathway, is negatively regulated by MIR-17–92. Therefore, we hypothesized that PTEN protein and mRNA expression would be decreased in pBL cases with 13q31 locus gain and high expression of MIR-17–92. Because PTEN negatively regulates the PI3K/AKT/mTOR pathway, we also assessed AKT activation in pBL tissues.

Methods:
We assessed PTEN protein expression by immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded (FFPE) pBL tissues from a cohort of patients (n=25) where MIR-17–92 expression levels and status of the 13q31 locus have been previously determined (Schiffman/Miles, Brit J Haematol 155:477, 2011). From FFPE tissues, we assayed PTEN mRNA levels by quantitative RT-PCR. The results of protein and mRNA expression were then correlated with presence or absence of a 13q31 gain and the expression level of MIR17. To evaluate AKT activation in pBL, we assayed for phospho-(p)-AKT by IHC. In addition, PTEN, AKT, and p-AKT protein levels were evaluated by western blotting in Raji and Ramos BL cell lines.

Results:
PTEN protein was weakly expressed in 5/25 cases (20%) of pBL. PTEN protein showed moderate nuclear and cytoplasmic staining in a subset of paracortical and germinal center lymphocytes in reactive lymph node control tissues, and vascular endothelial cells provided internal positive control in tumor tissue. pBL tissues showed decreased relative PTEN mRNA expression compared to reactive lymph node controls (1.56 vs. 2.61, p<3E-07). There was no significant difference in PTEN mRNA levels between PTEN protein positive and negative cases (1.27 vs. 1.61, p=0.22); cases with or without 13q31gain (1.49 vs. 1.57, p=0.60); or cases with high or low expression of MIR17. p-AKT was detected by IHC in 1/25 cases (4%). The BL cell lines Raji and Ramos showed very low levels of PTEN protein but no detectable p-AKT; total AKT was readily detectable.

Discussion:
pBL shows decreased PTEN mRNA, and most cases are negative for PTEN protein expression. Unexpectedly, higher MIR-17–92 expression level or 13q31 gain did not show an inverse relationship with PTEN expression at the protein or mRNA level. Despite decreased PTEN expression, p-AKT was detected in only 1/25 pBL cases and was not detected in BL cell lines. These findings suggest that decreased PTEN expression does not lead to AKT activation in pBL. Ongoing studies will investigate the potential of alternate PTEN targets and/or alternate targets for MIR-17–92 in pBL.

Disclosures:
No relevant conflicts of interest to declare.
Adverse Prognostic Impact of Vascular Endothelial Growth Factor Gene Polymorphism in Patients with Non-Hodgkin Lymphoma.
Authors: Kim Min Kyeong , Eom Hyeon Seok , Lee Hyewon , Han Mi Hwa , Kim Hyun-Ju , Park Weon Seo , Yun Tak , Kong Sun-Young 
Published: October 2019

Abstract
Abstract 2674
Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and progression of many types of cancer, and VEGF expression has been known to be associated with polymorphism of gene. However, the impact of polymorphisms of the VEGF gene on non-Hodgkin lymphoma (NHL) prognosis has not been fully elucidated. Here we investigated the association between VEGF polymorphisms and prognosis of NHL. The study involved 96 NHL patients treated at National Cancer Center, Korea. The median patient age was 57 years, and 60 patients (62.5%) were men. A total of 5 polymorphisms with heterozygous allele were analyzed. Clinical characteristics (e.g., cell lineage) and international prognostic index (IPI), including age, performance, LDH, stage and extra-nodal involvement, were evaluated and related to VEGF polymorphism. Hazard ratios (HRs) were determined in terms of risk for overall survival using Cox proportional hazard regression analysis. Diffuse large B cell lymphoma (n=73) was most common histologic type, and others were as follows: T-cell lymphoma (n=14), mantle cell lymphoma (n=6), and Burkitt lymphoma (n=3). IPI and stage were predictors for prognosis (p <0.01), and both index did not have correlation with VEGF polymorphisms. The genotype frequency of rs1570360 was GG (70%), GA (26%), and AA (4%), and it has significantly association with poor prognosis with HRs of 2.52 [95% confidence interval (CI), 1.36 to 4.67] in NHL patients and 2.41 [95% confidence interval (CI), 1.15 to 5.05] in DLBCL treated by rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), respectively. In IPI subgroup analysis, rs1570360 had association in higher IPI group (IPI ≥ 3) (p=0.02). These findings suggest that VEGF polymorphisms may be significant prognostic indicators for patients with NHL and DLBCL.

Disclosures:
No relevant conflicts of interest to declare.
Cerebral Small Vessel Disease In Patients With Sickle Cell Disease: Initial Findings With Ultra-High Field 7T MRI
Authors: der Land Veronica van , Zwanenburg Jaco J.M. , Biemond Bart J , Hendrikse Jeroen , Mutsaerts Henk-Jan , Engelen Marc , Nederveen Aart J. , Majoie Charles B.L.M. , Luijten Peter R. , Fijnvandraat Karin , Nederkoorn Paul J. 
Published: October 2019

Abstract

Introduction
Almost 40% of patients with a severe form of sickle cell disease (SCD) develop small silent cerebral infarctions (SCIs), often located in the deep white matter, that may be associated with cognitive impairment. In patients with cardiovascular disease or risk factors, occurrence of these SCIs is a well known phenomenon, and considered as part of ‘cerebral small vessel disease’. Currently, it is unknown whether small vessel disease is the underlying cause of SCIs in sickle cell disease. If we can identify imaging features supporting the hypothesis that cerebral small vessel disease occurs in patients with SCD, this may provide new targets for therapeutic interventions. The aim of the present study is to investigate the brain imaging features of neurologically asymptomatic young SCD patients with ultra-high field 7T MRI.

Methods
Ten consecutive, neurological asymptomatic patients with SCD (homozygous hemoglobin S) without other cardiovascular risk factors were included (mean age 23 years, range 19-25). Brain lesions were scored using a 3D magnetization prepared fluid attenuated inversion recovery scan (MP-FLAIR) and a dual-echo T2*-weighted scan for the visualization of small arteries and veins.

Results
With the exception of two patients, all displayed round and circumscript infarcts in the deep white matter of the frontal or parietal lobe (Table). Most lesions (82%) were <5 mm. In one patient (A) we identified 164 white matter infarcts (Figure 1). Strikingly, one patient (patient B) had several cortical micro-infarcts (Figure 2) although she had no neurological symptoms. These were associated with an occluded A1 and A2 segment of the anterior cerebral artery. In addition, this patient had unique pattern of white matter lesions, consisting of irregular shaped white matter infarcts, some located periventricular, and others close to the cortical infarcts. In two other patients (patients C and D) we identified an isolated cortical micro-infarct despite the absence of large vessel vasculopathy. In patient C, we found numerous hypo-intense areas symmetrically distributed in the deep white matter of the frontal and parietal lobe (Figure 3). These areas were associated with prominent transmedullary veins.

Conclusion
In our series of young and neurological asymptomatic SCD patients, we found the typical imaging features of SCIs in 8 out of 10 patients. Our findings suggest that patients with SCD may have manifestations of cerebral small vessel disease before the occurrence of symptoms, even at a young age and without other cardiovascular risk factors.

Disclosures:
No relevant conflicts of interest to declare.
CMR Survey In a Large Cohort Of TI Patients
Authors: Meloni Antonella , Lai Maria-Eliana , Vacquer Stefania , Mattei Roberto , Argento Crocetta , Maddaloni Domenico , Maggio Aurelio , Salvatori Cristina , Restaino Gennaro , Positano Vincenzo , Lombardi Massimo , Pepe Alessia 
Published: October 2019

Abstract

Introduction
Little is known about cardiac involvement in thalassemia intermedia (TI) using cardiovascular magnetic resonance (CMR). We investigated myocardial iron overload (MIO), biventricular parameters, and myocardial fibrosis in a large cohort of TI patients, underlying the differences between transfusion-dependent and non-transfusion-dependent patients.

Methods
We studied 252 adult TI patients (119 females, 39.5±10.4 years) enrolled in the MIOT Network. MIO was assessed using a multislice multiecho T2* approach. Biventricular function parameters were quantified by cine sequences. Myocardial fibrosis was evaluated by late gadolinium enhancement acquisitions.

Results
One-hundred and eighty-eight (74.6%) patients showed no MIO in any segment, 56 (22%) had an heterogeneous distribution (52 with global heart T2*≥20 ms), and 8 (0.3%) showed an homogeneous MIO.
Left ventricular (LV) and right ventricular (RV) dilatations were present in 113 (45%) and in 49 (19%) patients, respectively. LV dysfunction was present in the 18.0% of the cases while RV dysfunction in the 3.63%. High LV mass indexes were present in 22 (8.7%) patients.
Fifty-two/227 (22.9%) patients showed myocardial fibrosis. Myocardial fibrosis was associated to LV dysfunction (P=0.001) and high mass indexes (P=0.038).
One-hundred and fourteen patients were non-transfusion dependent (transfusion requirements absent or sporadic) while 138 patients were transfusion-dependent (regular transfusions). The mean age at start of chronic transfusions was 11.8 ± 12.3 years. Table 1 shows the comparison between the two groups. Non-transfusion-dependent patients showed significantly higher global heart T2* values and MIO with a global heart T2* < 20 ms was detected in two of them (one requiring occasional blood transfusions and one non transfused). Biventricular end-diastolic volume index, stroke volume index, left ventricular (LV) mass index, and LV cardiac index were significantly higher in the non-transfusion dependent group.

Conclusions
CMR plays a key role in the management of TI patients. Heart iron (global heart T2* < 20 ms) was not common, but a quarter of the patients had some pathological segments. A consistent number of patients had the stigmata of the high cardiac output state cardiomyopathy. Myocardial fibrosis was related to the high cardiac output state. The signs of the high output state were controlled in the transfusion-dependent-patients.

Disclosures:
No relevant conflicts of interest to declare.
Modulation Of T Cell Function Through L-Arginine Metabolism: A New Therapy From An Old Enemy
Authors: Fletcher Matthew B. , Ramirez Maria Elena , Sierra Rosa , Raber Patrick , Rodriguez Paulo 
Published: October 2019

Abstract
Recent studies have suggested the relevance of different energy metabolic pathways in the balance between protective T cell immunity and T cell anergy in tumors. We and others have suggested the role of the depletion of the non-essential amino acid L-arginine as a mechanism for the induction of T cell suppression in tumors. Therefore, we hypothesize that it is possible to metabolically regulate T cell responses simply through the modulation of L-arginine. In this study, we aimed to determine the effect of a pegylated form of the human L-arginine-metabolizing enzyme arginase I (peg-Arg I) in T cell responses. Activation of naïve murine T cells and antigen-specific CD4+ or CD8+ T cells in the presence of peg-Arg I prevented cell proliferation and production of IFNγ in vitro and in vivo. Similarly, peg-Arg I impaired proliferation and IFNg production in T cells activated with PMA/Ionomycin, suggesting that the effect of peg-Arg I was independent of T cell receptor (TCR) signaling. In fact, the anti-proliferative effect induced by peg-Arg I correlated with an arrest of T cells in the G0-G1 phase of the cell cycle, a decreased expression of cyclin D3 and cdk4, and a major inhibition of de novo translation. Interestingly, treatment of T cells with peg-Arg I did not impair the expression of the activation marker CD69, which correlated with an intact mitochondrial biogenesis. As a result, peg-Arg I did not have an effect in oxygen consumption by mitochondrial respiration (OCR), but significantly blocked glycolytic pathways in activated T cells. Furthermore, peg-Arg I treated T cells increased the expression of genes associated with integrated stress responses (IRS) and arrest in translation including GCN2, Chop, and Atf4. We then tested the effect of peg-Arg I in mouse models of graft versus host disease (GVHD) and inflammatory bowel disease (IBD), both mediated through activated T cells. Peg-Arg I significantly extended the survival of mice in these 2 disease models, which was associated with a decreased production of IFNg. Altogether, these results suggest the potential effect of the modulation of the metabolism of L-arginine as a means to regulate T cell responses. Continuation of this study will advance in the understanding of the metabolic effects of L-arginine in T cell function, which could enable the development of therapies to modulate T cell responses in transplantation or autoimmunity.

Disclosures:
No relevant conflicts of interest to declare.
Age-Associated DNA Methylation Signature Reveals Premature Aging In Patients With Aplastic Anemia and Dyskeratosis Congenita Which Correlates With Telomere Shortening
Authors: Beier Fabian , Weidner Carola I. , Lin Qiong , Ziegler Patrick , Zenke Martin , Brümmendorf Tim H. , Wagner Wolfgang 
Published: October 2019

Abstract

Introduction
Telomere length (TL) reflects the replicative potential of a cell and is a useful parameter to assess chronological age of an organism. Aplastic anemia (AA) and dyskeratosis congenita (DKC) are bone marrow failure syndromes (BMFS) characterized by shortened telomeres compared to age-matched healthy individuals in peripheral blood leukocytes. Human aging is associated with DNA methylation (DNAm) changes at specific sites in the genome. The aim of this study was to analyze whether aging specific epigenetic modifications can be used to track donor age and reflect premature aging in patients with AA and DKC.

Methods
A large set of publically available DNAm profiles were used to identify an Epigenetic-Aging-Signature. The DNAm level of three corresponding CpG sites was then analyzed by pyrosequencing after bisulfite conversion. The results were used for linear regression models for age predictions. This method was applied with peripheral blood leukocytes of a training as well as a validation set. Furthermore, TL analysis by flow-FISH of peripheral blood leukocytes of 106 healthy donors was used to generate age-adapted reference values. Pyrosequencing and telomere length analysis were carried out in 16 AA and 6 DKC patients

Results
Our analysis revealed that DNAm levels at three AR-CpGs – located in the genes ITGA2B, ASPA and PDE4C – were best suited for age predictions. The mean absolute deviation from chronological age in the validation set of 69 donors was less than 5 years. Age-adapted telomere length analysis revealed significant telomere attrition in AA (- 1.1 kb) and DKC patients (-3.7 kb, all below the 1% percentile). In analogy, the epigenetic changes revealed premature aging in AA patients – particularly in those which revealed extensive telomere attrition.

Conclusion
Our results indicate that patients with AA and DKC undergo massive premature aging on the epigenetic level comparable to the observed telomere shortening in these diseases. Determination of this newly defined Epigenetic-Aging-Signature in combination with telomere length measurement may be used to further refine diagnosis of AA and DKC in the clinical setting.

Disclosures:
No relevant conflicts of interest to declare.
Aberrant 5-Hydroxymethylcytosine Levels Correlate With Poor Overall Survival In Acute Myeloid Leukemia
Authors: Kroeze Leonie I , Aslanyan Mariam G , van Rooij Arno , Koorenhof-Scheele Theresia N , Massop Marion , Carell Thomas , Boezeman Jan B , Marie Jean-Pierre , Halkes Constantijn J.M. , de Witte Theo M. , Huls Gerwin , Suciu Stefan , Wevers Ron , van der Reijden Bert A. , Jansen Joop H. 
Published: October 2019

Abstract

Background
Patients with acute myeloid leukemia (AML) frequently harbor mutations in genes involved in the DNA (hydroxy)methylation pathway (DNMT3A, TET2, IDH1, and IDH2). In addition, changes in DNA methylation have been implicated in the pathogenesis of AML. Recently it was discovered that TET proteins are able to convert 5-methylcytosine into 5-hydroxymethylcytosine (5hmC), which is an important intermediate in the demethylation pathway. In this study, we measured 5-hydroxymethylcytosine levels in AML patients, and correlated these with mutational status and overall survival (OS).

Patients and methods
Samples from 206 clinically and molecularly well-characterized younger adult AML patients (≤60 years), included in the EORTC/GIMEMA AML-12 06991 clinical trial, were analyzed for mutations in DNMT3A, TET2, IDH1 and IDH2. 5-hydroxymethylcytosine levels were measured using HPLC-MS/MS.

Results
In healthy control cells, 5hmC levels were confined to a narrow range (1.5 fold difference), whereas in AML cells, a much wider range was detected (15 fold difference). In remission, 5hmC values were normalized to levels comparable to healthy bone marrow and peripheral blood, indicating that the aberrant 5hmC levels at diagnosis are intrinsic to the leukemic cells. Patients with mutations in TET2 and patients with mutations in IDH1/2 had significantly lower levels of 5hmC compared to patients without mutated TET2 and IDH1/2 (both P<.001), whereas mutations in DNMT3A did not influence 5hmC levels. Patients with bi-allelic TET2 inactivation displayed lower 5hmC levels than patients with one affected allele (P=.003). Among the patients that did not harbor TET2 or IDH mutations, still a wide variation in 5hmC levels was observed, and importantly, both low and very high 5hmC levels correlated with inferior OS (P=.02, HR=1.80 and P=.04, HR=1.97, respectively). Multivariate analysis revealed that abnormal levels of 5hmC were independent prognostic indicators for OS. The difference in OS could not be explained by an initial inferior response to therapy, however, the relapse rate was considerably higher in patients with low and very high 5hmC levels compared to patients with intermediate 5hmC.

Conclusion
Both low and very high levels of 5hmC are markers of poor prognosis in AML, lending further support for testing therapies targeting the DNA hydroxymethylation pathway.

Disclosures:
No relevant conflicts of interest to declare.
Epigenetic Gene Regulation By JAK1 In Diffuse Large B-Cell Lymphoma
Authors: Rui Lixin 
Published: October 2019

Abstract
Diffuse large B-cell lymphoma (DLBCL) grows rapidly and represents 30% to 40% of newly diagnosed lymphomas. The most aggressive subtype, termed activated B-cell-like diffuse large B-cell lymphoma (ABC DLBCL), is dependent on the autocrine cytokines IL-6 or IL-10 for survival. Our recent work has demonstrated that secretion of the cytokines in these lymphoma cells is mediated by aberrant NF-κB activation, including gain-of-function mutations in the MYD88 gene. In this study, we will dissect the molecular mechanisms of the cytokine signaling in lymphomagenesis.
We have evidence that the Janus kinase downstream of the cytokine signaling is JAK1. I obtained a surprising result demonstrating that JAK1 localization is largely nuclear, and that JAK1 can modify the nuclear histone protein H3 through phosphorylating tyrosine 41 (H3Y41). We and others have discovered that this chromatin modification can be initiated by the homologue JAK2 in leukemia cells as well as in primary mediastinal and Hodgkin lymphoma cells. H3Y41 phosphorylation displaces the inhibitory protein HP1 from chromatin and activates gene transcription. Genome-wide mapping by Chip-Seq using antibodies specific for H3Y41 phosphorylation identified 2,582 candidate genes modified by activated JAK1 in ABC DLBCL cells. These include important oncogenes such as MYC, key NF-kB pathway genes, and AP1 genes whose function is not appreciated in this lymphoma. Given that inhibition of some of these genes by RNA interference or by pharmaceutical inhibitors is lethal to cultured ABC DLBCL cells, they will be considered potential molecular targets for therapeutic development.

Disclosures:
No relevant conflicts of interest to declare.
EZH2 Mediates Resistance To Apoptosis In Nktl By Activating Nfkb Signaling Through Repression Of TNFAIP3/A20 By H3K27 Trimethylation
Authors: Loong Koh Tze 
Published: October 2019

Abstract
Extranodal nasal-type natural killer/T-cell lymphoma (NKTL) is a rare and aggressive form of lymphoma with poor outcome. A better understanding of the molecular pathophysiology of the disease is needed to development better treatment and improve patient’s outcome. We previously showed that EZH2, a histone methyltransferase, is abnormally over-expressed in NK cell lines as compared to normal NK cells, and may therefore be important for the pathogenesis and treatment of NKTL. 3- Deazaneplanocin A (DZNep) is a drug that can deplete EZH2 levels. Downregulation of EZH2 by DZNep induces apoptosis in a panel of NKTL cell lines but not normal NK cells. We perform gene expression studies to identify possible mechanism by which DZNep induce apoptosis in NKTL. There is significant enrichment of NFKB target genes amongst the genes downregulated after DZNep treatment. In addition, 2 inhibitors of the NFKB pathways, TNFAIP3/A20 and NFKBIA were upregulated. The downregulation of these genes were validated by PCR. We further found that NFKB2 was downregulated after DZNep treatment on western blot suggesting that NFKB signaling was downregulated. Similar results were obtained when we silence EZH2 using siRNA suggesting that much of the effect of DZNep is mediated through downregulation of EZH2. When TNFAIP3/A20 was expressed in untreated NKTL cells, apoptosis was induced. Conversed with TNFAIP3/A20 was knocked down in cells treated by DZNep, DZNep induced apoptosis was reduced. These data suggest in NKTL, EZH2 downregulate TNFAIP3/A20 and activate NFKB leading to resistance to apoptosis. We next investigated if EZH2 directly regulate TNFAIP3/A20 expression at its promoter. Using chromatin immunoprecipitation, we found that there is high occupancy of EZH2 and H3K27me3 at the TNFAIP3/A20 promoter in NKTL. Upon EZH2 knockdown, EZH2 and H3K27me3 is markedly reduced at the promoter and there is concurrent increase in TNFAIP3 expression. Consistent with cell lines data, in clinical samples, there is a strong association between H3K27me3 and nuclear p50 expression on a tissue microarray of NKTL (Chi-square p-value 0.01). We have therefore uncovered a novel mechanism by which EZH2 activates the NFKB pathway through its histone methyltransferase activity on the promoter of TNFAIP3/A20 resulting in resistance of NKTL to apoptosis.

Disclosures:
No relevant conflicts of interest to declare.