tbuckley/cabot-search huggingface dataset:
UDG is a major DNA glycosylase having activity on F:T mispairs: identifying a new target of fludarabine
Authors: Alina Bulgar, Lan Li, Yan Xu, Stanton Gerson, Lili Liu
Journal: Cancer Research (2008)

2337  We have observed that the cytotoxic effect of fludarabine is enhanced by methoxyamine in vitro and in xenograft settings. Methoxyamine specifically binds to an abasic site (AP), an intermediate produced during the process of base excision repair (BER), and turns the repairable DNA damage into a lethal lesion, leading to cell death. It acts as an inhibitor of BER. Thus the potentiation of fludarabine by methoxyamine suggests that the incorporation of F-ara-adenosine as an abnormal base initiates the sequential repair cascade to produce the AP sites through a DNA glycosylase, the first step in BER. However, the molecular mechanismof BER to process incorporated fludarabine is not known. In this study, using oligonucleotide substrates containing F-ara-adenosine: thymidine mispairs (F:T), we examined the cleavage activity of several purified DNA glycosylases (including UDG, Aag, OGG1, Mut Y and TDG), based on the fact that most of them are highly specific for a certain type of altered base, but some have more relaxed specificity. Our results show that only uracil DNA glycosylase (UDG) has enzymatic activity to recognize F:T mispairs and to excise 2-fluoroadenine from DNA, displaying a time- and concentration-dependent cleavage. The reactants of purified UDG and oligonucleotide were collected and analyzed using HPLC-ESI-mass spectrometer and 2-fluoroadenine was identified as the cleaved product after reaction. Similarly, cleaved products were seen when the F-ara-A oligonucleotide substrates were incubated with cell extracts from HL60 or Jurkat cells. To evaluate the relative substrate specificity of UDG, the kinetics of excision of F-ara-A was compared with Uracil in a double-stranded oligonucleotide. The results show that F-ara-A is substrate for UDG, but the specificity of UDG for F-ara-A residues is 20 times lower compared to uracil that is the specific substrates of UDG. Moreover, the cleavage activity of UDG in purified form or in cell extracts can be abolished or reduced by UDG specific antibody (at a concentration of 10 μg/ml) or uracil glycosylase inhibitor (UGI, 2 Units), respectively. Our results indicate for the first time that in cell BER can process incorporated fludarabine through the recognition and removal of 2-fluoroadenine in DNA by UDG. The finding identifies a new target of fludarabine and reveals a new therapeutic strategy by targeting BER for the treatment of hematological malignancies.
Nonclassical Monocytes in Health and Disease
Authors: Prakash Babu Narasimhan, Paola Marcovecchio, Anouk A.J. Hamers, Catherine C. Hedrick
Journal: Annual Review of Immunology (2019)

Monocytes are innate blood cells that maintain vascular homeostasis and are early responders to pathogens in acute infections. There are three well-characterized classes of monocytes: classical (CD14 + CD16 − in humans and Ly6C hi in mice), intermediate (CD14 + CD16 + in humans and Ly6C + Treml4 + in mice), and nonclassical (CD14 − CD16 + in humans and Ly6C lo in mice). Classical monocytes are critical for the initial inflammatory response. Classical monocytes can differentiate into macrophages in tissue and can contribute to chronic disease. Nonclassical monocytes have been widely viewed as anti-inflammatory, as they maintain vascular homeostasis. They are a first line of defense in recognition and clearance of pathogens. However, their roles in chronic disease are less clear. They have been shown to be protective as well as positively associated with disease burden. This review focuses on the state of the monocyte biology field and the functions of monocytes, particularly nonclassical monocytes, in health and disease.
LRP1 Deficiency in Vascular SMC Leads to Pulmonary Arterial Hypertension That Is Reversed by PPARγ Activation
Authors: Laurent Calvier, Philippe Boucher, Joachim Herz, Georg Hansmann
Journal: Circulation Research (2019)

Arterial remodeling-a hallmark of many cardiovascular pathologies including pulmonary arterial hypertension (PAH)-is regulated by TGFβ1 (transforming growth factor-β1)-TGFβ receptors and the antagonistic, vasoprotective BMPR2 (bone morphogenetic protein receptor 2)-PPARγ (peroxisome proliferator-activated receptor-γ) axis. However, it is unclear which factors drive detrimental TGFβ1 pathways in the hypertensive pulmonary vasculature.We hypothesized that LRP1 (low-density lipoprotein receptor-related protein 1) expression is decreased in PAH, leading to enhancement (disinhibition) of TGFβ1 signals and that the PPARγ agonist pioglitazone can restore vascular homeostasis and prevent PAH resulting from LRP1 deletion in vascular smooth muscle cells (SMCs).Targeted deletion of LRP1 in vascular SMC (smLRP1-/-) in mice disinhibited TGFβ1-CTGF (connective tissue growth factor) signaling, leading to spontaneous PAH and distal pulmonary arterial muscularization as assessed by closed-chest cardiac catheterization and anti-αSMA staining. Pioglitazone inhibited the canonical TGFβ1-CTGF axis in human pulmonary artery SMC and smLRP1-/- main pulmonary artery (CTGF and NOX4) and reversed PAH in smLRP1-/- mice. TGFβ1 boosted pSmad3 in PASMC from smLRP1-/- mice versus controls. Pioglitazone-activated PPARγ binds to Smad3 in human pulmonary artery SMC (coimmunoprecipitation), thereby blocking its phosphorylation and overriding LRP1 deficiency. Finally, mRNA and protein expression of LRP1 was decreased in pulmonary plexiform lesions of patients with end-stage idiopathic PAH (laser capture microdissection, qPCR, and immunohistochemistry). Downregulation of LRP1 protein was also demonstrated in explanted PASMC from patients with PAH and accompanied by enhanced TGFβ1-pSmad3-CTGF signaling and increased TGFβ1-induced PASMC proliferation that was prevented by pioglitazone.Here, we identify LRP1 as an integrator of TGFβ1-mediated mechanisms that regulate vascular remodeling in mice and clinical PAH and PPARγ as a therapeutic target that controls canonical TGFβ1 pathways. Hence, pharmacologic PPARγ activation represents a promising new therapy for patients with PAH who lack the vasoprotective LRP1 in vascular SMC.
DIPG-17. IMPROVING THE RADIOSENSITIVITY OF DIFFUSE INTRINSIC PONTINE GLIOMAS BY MODULATING BIOENERGETIC PATHWAYS
Authors: Han Shen, Cecilia Chang, Harriet Gee, Geraldine O’Neill, Victoria Prior, Anneke Blackburn, Eric Hau
Journal: Neuro-Oncology (2019)

Diffuse intrinsic pontine glioma (DIPG) is the leading cause of brain tumor-related death in children and radiotherapy (RT) is the only form of treatment that offers a transient benefit. Following completion of RT, almost all DIPG recur locally secondary to radioresistance. Therefore, the identification of therapeutic targets that modulate the radiosensitivity of DIPG cells offers a pathway to the development of effective therapies. In the present study, anti-diabetic biguanides (metformin and phenformin) and a pyruvate dehydrogenase kinase inhibitor (DCA) have been tested in combination with RT on patient-derived DIPG cultures. As a single agent, a superior anti-proliferative activity was observed from phenformin, which reduced the half maximal inhibitory concentration (IC50) values to 20- to 30-fold compared to metformin. When combined with DCA, the co-treatment led to a consistent synergistic inhibition, with a broad range of combinatorial doses showing combination index (CI) less than 1. DIPG cells treated with phenformin and/or DCA were more sensitive to RT showing significantly less clonogenicity when triple combination was applied. Mechanistically, apoptosis was induced by the combination, evidenced by the upregulation of apoptotic markers (cleaved PARP and cleaved caspase 3) and downregulation of anti-apoptotic marker MCL-1. Additionally, the combination synergistically induced higher level of Reactive Oxygen Species, which further upregulated gamma-H2AX, a hallmark of DNA double-strand breaks. Moreover, PARP, a key enzyme that is responsible for single-strand breaks, was also inhibited by the combinatorial treatment, indicating another layer of radiosensitizing machinery. Taken together, this study provides the proof of concept that dual-blockade of bioenergetic pathways can more effectively improve the radiosensitivity of DIPG cells. We are currently evaluating the efficacy of triple combination with phenformin, DCA and RT on a cohort of patient-derived xenograft models of DIPG to validate our in vitro findings.
IMMU-06. INVESTIGATING IMMUNOSUPPRESSIVE MECHANISMS IN THE TUMOR MICROENVIRONMENT OF HIGH-RISK NEUROBLASTOMA; AN IMMUNOCOMPETENT, MYCN-DRIVEN, NON-GERMLINE GEM MODEL
Authors: Marie Menard, Lauren McHenry, Nicole Nasholm, Shannon Wong-Michalak, Edbert Lu, Erin Simonds, W Clay Gustafson, William A Weiss
Journal: Neuro-Oncology (2019)

Combining anti-GD2 ganglioside monoclonal antibody with immune-activating cytokines improves survival in high-risk neuroblastoma, a breakthrough for immunotherapy in this disease. However, approaches such as immune checkpoint blockade, anti-GD2 CAR-T cells, and tumor vaccines have thus far shown limited success. While a better understanding of the tumor microenvironment (TME) promises to improve the success of immunotherapy strategies, few immunocompetent models exist for high-risk neuroblastoma. We used a 30-parameter mouse-specific CyTOF mass cytometetry panel to characterize the TME of neuroblastoma arising in TH-MYCN transgenic mice. The TME was dominated by tumor-associated macrophages (TAMs) and devoid of T, B or NK cells; recapitulating the TME of human high-risk neuroblastoma. The TH-MYCN model is highly penetrant only in the 129/SvJ strain however, a challenge to leveraging immunological tools available mainly in the C57/BL6 background. We therefore created a non-germline GEM model in which primary trunk neural crest cells isolated from C57BL6/J embryos were modified genetically by transducing MYCN (MYCN-nGEMM). Orthotopic transplantation in renal capsules resulted in neuroblastoma with 50% penetrance. Co-expression of ALKF1174Lwith MYCN resulted in 80% penetrance and decreased latency. Cell lines could be derived robustly from these tumors and serially transplanted with 100% penetrance. CyTOF analysis of MYCN-nGEMM tumors also revealed a highly immunosuppressive TME similar to TH-MYCN tumors, with 80% of immune cells being TAMs, and only 5% T-cells. MYCN-nGEMM tumors were then treated with various immunotherapies, including anti-GD2 antibody, checkpoint inhibitors, and a combination of both, and changes in the TME were analyzed by CyTOF. In summary, we have characterized an immune-intact model for MYCN-driven neuroblastoma that can leverage modern methods to rapidly modify the murine genome, enabling customization of this mouse model for immunological research. We propose this model to understand the immunosuppressive mechanisms of MYCN-driven neuroblastoma tumors, and evaluate the potential of combining MYCN-directed therapies with immunotherapy.
Evidence for an IL-6–high asthma phenotype in asthmatic patients of African ancestry
Authors: Steven R. White, Bharathi Laxman, Edward T. Naureckas, D. Kyle Hogarth, Julian Solway, Anne I. Sperling, Carole Ober
Journal: Journal of Allergy and Clinical Immunology (2019)

High circulating IL-6 may define a phenotype of asthma associated with obesity and systemic inflammation. We demonstrate that circulating IL-6 is higher in African-American patients with asthma, and that race-specific thresholds should be considered.
COMPARISON OF NON-EXPOSURE SIMPLE SUTURING ENDOSCOPIC FULL-THICKNESS RESECTION (NESS-EFTR) AND LECS FOR GASTRIC SUBEPITHELIAL TUMORS
Authors: CG Kim, DI Choi, HM Yoon, BW Eom, KW Ryu, YW Kim, YI Kim, JY Lee, IJ Choi
Journal: Endoscopy (2019)

Laparoscopy and endoscopic cooperative surgery (LECS) has the limitation of tumor exposure to peritoneal cavity. Recently, endoscopic full-thickness resection (EFTR) method which does not expose the tumor to peritoneal cavity (NESS-EFTR) was developed. We evaluated the NESS-EFTR technique with LECS.
MEDU-18. FUNCTIONAL BRAIN NETWORK PROPERTIES AND COGNITIVE IMPAIRMENT IN ADOLESCENTS FOLLOWING RADIATION THERAPY
Authors: Melanie Morrison, Angela Jakary, Erin Felton, Schuyler Stoller, Justin Yuan, Sabine Mueller, Janine Lupo
Journal: Neuro-Oncology (2019)

INTRODUCTION: Radiation therapy (RT) plays an integral role in the treatment of pediatric brain tumors, despite its association with significant long-term adverse effects including cognitive impairments and RT-induced vascular injury. Numerous studies have shown steady decreases in Intelligence Quotient in the years after RT and instances of domain-specific cognitive decline that are more severe in patients treated with a whole brain versus a focal radiation approach. In this study we evaluated the relationship between functional brain network properties derived from resting-state functional MRI (rsfMRI) and cognitive performance measures. rsfMRI may serve as a tool for early prediction of patient outcome and as an adjunct to cognitive testing batteries in instances where patients cannot effectively complete the tasks, e.g. young age. METHODS: Ten patients (ages 6–22 years) treated with RT for 0.10–18 years prior, and two nonirradiated control patients (ages 13–14 years) were scanned on a 7-Tesla system. High resolution T1-weighted anatomical and rsfMRI data were acquired. A computerized cognitive battery (Cogstate) was employed to assess multiple domains of cognitive function. Global measures of network segregation, integration, and regional strength were extracted from rsfMRI connectivity matrices using the AAL (Automated Anatomical Labelling) atlas and compared to cognitive performance measures using the Pearson correlation coefficient. RESULTS: Across all tasks, patients performed poorly relative to age-matched healthy subjects. A visual memory task (continuous paired associate learning) consistently showed good correlations (r > 0.7) with global and regional network measures. Visuospatial and learning/episodic cognitive domains revealed slighter lower correlations (r > 0.6) across the majority of network measures. CONCLUSIONS: This work suggests that rsfMRI functional connectivity matrices can provide network metrics that reflect cognitive performance measures in adolescents after RT. Ongoing work will evaluate these data in a larger cohort with alternative atlases and in conjunction with structural brain networks
Abstract 21186: Amelioration of Myocardial Stunning in Pigs Undergoing Cp/cpb With Bkca Channel Activator Supplemented Cardioplegia
Authors: Neel R Sodha, Brittany A Potz, Frank W Sellke, Jun Feng, Martin Kolodziejczak, Brenda Cordeiro, Richard T Clements
Journal: Circulation (2017)

Introduction: Activation of mitochondrial large conductance Ca++-activated K+ channels (BKCa) is cardioprotective in cell and rodent isolated heart models of cardioplegic arrest and reperfusion. We previously demonstrated cardioprotection is associated with reduced mitochondrial ROS generation and reorganization of individual electron transport chain complexes into physically associated respiratory supercomplexes (SC) made of ETC complex I/III/IV. In this study, we examined the efficacy of BKCa activation during cardioplegic arrest in a clinically relevant large animal study using pigs subjected to CP/CPB and reperfusion. Methods: 50 kg Yorkshire pigs of either sex were subjected to CP/CPB (hyperkalemic cold blood CP, 1 hr) with or without the BKCa activator mallotoxin (MTX (aka rottlerin)) supplied in the CP solution, followed by reperfusion (1hr). Pigs were instrumented with a PV catheter and IVC occlusions performed at baseline and 30 and 60 mins after weening from bypass. Following surgery, mitochondria were isolated and subjected to Blue-Native PAGE and immunoblotting of ETC complexes to visualize large (~100-1500 kD) mitochondrial SC. Results: Baseline hemodynamics were similar between groups. CP/CPB resulted in significant myocardial stunning in pigs as assessed by LVDP (pre 64.8 mmHg vs post 42.0, P&lt;.05 ), +/-dP/dt (pre 971.4 and -911.8 vs post:588.0 and -541.0, P&lt;.05 ), and end-systolic elastance (Ees: pre 1.28 vs post .63, P=0.1 ) at 60 min reperfusion. However, pigs arrested with CP containing MTX (500 nM) exhibited greatly reduced myocardial stunning with significant improvements in LVDP (pre:65.7 post:67.8 mmHg, P&lt;.01 vs post CP/CPB group) +/- dP/dt (pre:1026.0 and -911.8 vs post:1441.7 and -984.8 mmHg/s, P=.02 and .04 vs CP/CPB) and Ees (pre 1.1, post 1.35, P=.02 vs CP/CPB). LV mitochondria isolated from both groups had two major I/III/IV mitochondrial SC’s of ~1300 (SC1) and ~1000 kD (SC2) as assessed by BN-PAGE and immunoblot. The CP/CPB + MTX group had significant increases in both SC1 (6.0 % vs 18.0%, P=.01) and SC2 (19.7% vs 52.3%, P&lt;.01) expressed as percent of total assembled complex IV. Conclusion: Addition of a BKCa activator to CP solutions ameliorates myocardial stunning in large animals subjected to CP/CPB and reperfusion.
MEDU-06. TARGETING MYC AND OTX2-DRIVEN TRANSCRIPTIONAL DEPENDENCIES OF GROUP 3 MEDULLOBLASTOMA THROUGH CDK7 INHIBITION
Authors: Lei Zhang, Meng Li, Linjun Hou, Liye Zhang, Yujie Tang
Journal: Neuro-Oncology (2019)

MB cells.Neuronal differentiation genes encoding transcription factors (TFs) were associated with loss of H3K27me3 modifications suggesting de-repression in TF expression.Members of the PAX gene family of TFs were significantly de-repressed and their role in Group 3 MB progression is unknown.PAX3 and PAX6 expression is significantly lower in Group 3 MB patients and low expression is correlated with significantly reduced patient survival.Interestingly, OTX2 directly binds to PAX3 and PAX6 and restricts their expression in Group 3 MB cells.Over-expressing PAX3 and PAX6 in Group 3 MB cells reduced tumorsphere number, self-renewal and cell cycle properties while increasing neuronal differentiation.In addition, PAX3 expression significantly increased survival and reduced tumor size following intracerebellar transplantation.RNA-sequencing of tumorspheres over-expressing PAX3 and PAX6 revealed a reduction in Group 3 signatures including GABAergic and glutamatergic signalling.Downregulation of genes involved in mTOR signalling was specifically observed in PAX3 overexpressing tumorspheres, which may contribute to the differential survival observed in vivo.Similar changes in gene signatures were also demonstrated following OTX2 silencing in multiple Group 3 MB cell lines.Our results demonstrate that OTX2 controls cell fate decisions in Group 3 MB by regulating PAX gene expression, and that targeting downstream molecular signatures may reveal novel therapeutic targets for these highly aggressive tumors.
Role of Treatment Deintensification in the Management of p16+ Oropharyngeal Cancer: ASCO Provisional Clinical Opinion
Authors: David J. Adelstein, Nofisat Ismaila, Jamie A. Ku, Barbara Burtness, Paul L. Swiecicki, Loren Mell, Jonathan J. Beitler, Neil Gross, Christopher U. Jones, Marnie Kaufman, Quynh-Thu Le, Thomas J. Semrad, Lillian L. Siu, John A. Ridge
Journal: Journal of Clinical Oncology (2019)

An ASCO provisional clinical opinion offers timely clinical direction to ASCO's membership after publication or presentation of potentially practice-changing data from major studies. This provisional clinical opinion addresses the role of treatment deintensification in the management of p16+ oropharyngeal cancer (OPC).For patients with p16+ OPC, current treatment approaches are well established. In the good-prognosis subset of nonsmoking p16+ patients with early-stage disease, these treatments have been highly successful, albeit with significant associated acute and late toxicity. Deintensification of surgical, radiation, and medical treatment in an effort to reduce toxicity while preserving high survival rates is an appropriate therapeutic objective currently being explored in patients who are experiencing the best treatment results. However, careful delineation of this good-risk subset is essential. While the current eighth edition of the American Joint Committee on Cancer staging system is prognostically robust, it should not be interpreted as reason to alter therapeutic decisions or justify treatment deintensification. The development of transoral surgical techniques and the adoption of intensity-modulated radiation therapy planning have been transformative in disease management and suggest potentially beneficial approaches. Recent advances in systemic treatments have been notable. The optimal integration and modification of these modalities to ameliorate toxicity has not been defined and remains an important focus of current investigation.The hypothesis that de-escalation of treatment intensity for patients with p16+ OPC can reduce long-term toxicity without compromising survival is compelling and necessitates careful study and the analysis of well-designed clinical trials before changing current treatment standards. Treatment deintensification for these patients should only be undertaken in a clinical trial. Additional information is available at www.asco.org/head-neck-cancer-guidelines .
Types of Erythropoietin-Stimulating Agents and Mortality among Patients Undergoing Hemodialysis
Authors: Yusuke Sakaguchi, Takayuki Hamano, Atsushi Wada, Ikuto Masakane
Journal: Journal of the American Society of Nephrology (2019)

Significance Statement Although both short-acting and long-acting erythropoietin-stimulating agents (ESAs) are used to treat anemia in patients undergoing hemodialysis, the relative effects on survival of these ESA types are unknown. In this nationwide, registry-based cohort study enrolling 194,698 patients on hemodialysis, the authors found that long-acting ESA users showed a 13% higher rate of death than short-acting ESA users ( P &lt;0.001) during the 2-year follow-up period. The difference in risk was pronounced among patients receiving high doses of ESA, for whom the adjusted 2-year number needed to harm for death was 30.8. Survival of long-acting ESA users who achieved more optimal hemoglobin levels was inferior to that of short-acting ESA users. Among patients on hemodialysis, long-acting ESA use might be associated with an increased rate of death compared with short-acting ESA use. Background Despite the widespread use of erythropoietin-stimulating agents (ESAs) to treat anemia in patients undergoing hemodialysis, the relative mortality risks associated with use of different types of ESAs are unknown. Methods To compare the mortality risk associated with use of short-acting ESAs versus long-acting ESAs, we conducted a nationwide cohort study of 194,698 hemodialysis patients in Japan who received either a short-acting (epoetin α / β or epoetin κ ) or a long-acting (darbepoetin or epoetin β pegol) ESA. Study outcomes were 2-year all-cause and cause-specific mortality. In addition to Cox proportional hazards models, we performed an instrumental variable analysis in which facility-level long-acting ESA prescription rates were taken as the instrumental variable. Results During the 2-year follow-up period, 31,557 deaths occurred. In a multivariable Cox model, long-acting ESA users had a 13% higher rate of deaths compared with short-acting ESA users, a significant difference ( P &lt;0.001). Similar results were obtained in other analyses. This difference in risk was pronounced among patients receiving high doses of ESA (for whom the adjusted 2-year number needed to harm for death was 30.8). Long-acting ESA use was associated with an increased rate of death from cardiovascular diseases, infection, and malignancies. In the instrumental variable analysis, long-acting ESA users remained at a significantly higher risk of death. Compared with anemic (hemoglobin 9.0–9.9 g/dl) short-acting ESA users, long-acting ESA users who achieved more optimal hemoglobin levels (10.0–10.9 g/dl) showed a higher mortality rate. Conclusions Among patients undergoing hemodialysis, use of long-acting ESAs might be associated with a higher risk of death than use of short-acting ESAs.