tbuckley/cabot-search huggingface dataset:
GENE-35. IDH1-R132H INDUCES AN EPIGENETIC REPROGRAMMING IN GLIOMA IMPACTING MEDIAN SURVIVAL, DNA-DAMAGE RESPONSE AND RADIO-SENSITIVITY
Authors: Felipe Nunez, Flor Mendez, Padma Kadiyala, Mahmoud Alghamri, Stephen Carney, Mats Ljungman, Tingting Qin, Maureen Sartor, Sriram Venneti, Costas Lyssiotis, Joseph Costello, Cameron Herting, Dolores Hambardzumyan, Maria Figueroa, Pedro Lowenstein, Maria Castro
Journal: Neuro-Oncology (2018)

IDH1-R132H is the most common mutation in lower-grade glioma and secondary glioblastoma. It is expressed in combination with ATRX and p53 inactivation in a mIDH1 glioma subtype which has been associated with better prognosis. We hypothesized that this is mediated by the impact of epigenetic changes on DNA-repair and DNA damage response (DDR) which maintain genome stability. To investigate this, we developed a mouse glioma model harboring IDH1-R132H, TP53-knockdown and ATRX-knockdown. Our results show that IDH1-R132H increases median survival (> 2 fold) compared with wt-IDH1 tumor bearing mice. Mutant-IDH1 tumors exhibit increased histone-3 methylation, and blocked neural cell differentiation. ChIP-seq, RNA-seq and Bru-seq data showed that genes involved in DNA-repair and DDR were upregulated in the mIDH1 mouse model. We also found differential enrichment of gene ontology terms related with DDR. Assessments of DNA-repair activity were performed in response to radiation (IR), i.e., H2AX and ATM phosphorylation, nuclear gH2AX and 53BP1 foci formation. These experiments were complemented with DNA-repair reporter assays. Our results demonstrate that mIDH1 mouse NS and human glioma cells exhibit increased DNA-repair and DDR activity, and enhanced genomic stability. This phenotype correlated with the response to radiation observed in vitro and in glioma bearing mice: IDH1-R132H expression in the genetic context of ATRX and TP53 inactivation elicits radio-resistance. Pharmacological inhibition of ATM or CHK1/2, two essential kinases in the DDR pathways, restored tumors’ radio-sensitivity. This results were also validated in human glioma cells with endogenous expression of mIDH1, and in an alternative (NRAS independent) mIDH1 glioma model. In conclusion, genetically engineered mice harboring glioma encoding mIDH1, ATRX and TP53 knockdown displayed increased MS, increased DNA-repair, DDR and genomic stability, which hampers radiation efficacy. Our findings reveal a novel therapeutic approach for mIDH1 glioma patients, targeting DDR which would enhance the therapeutic efficacy of radiation.
EXTH-74. MOLECULAR MECHANISMS OF ANTI-TUMOR ACTION OF TTFIELDS DETERMINED BY MEASUREMENTS AND MODELING OF ELECTRO-CONDUCTIVE PROPERTIES OF MICROTUBULES
Authors: Jack Tuszynski, Iara Santelices, Aarat Kalra, Clayton Bell, Cameron Hough, Piyush Kar, Vahid Reazania, John Lewis, Karthik Shankar
Journal: Neuro-Oncology (2018)

Biological effects of AC electric fields at frequencies between 100–300 kHz discovered a decade ago are being applied to cancer cells as a therapeutic modality in the treatment of glioblastoma multiforme (GBM). They are called Tumor Treating Fields (TTFields) as they disrupt cell division. Based on our electro-conductive measurements and modeling, we provide an assessment of possible molecular-level mechanisms. Computer simulations and experimental measurements carried out for microtubules and actin filaments are presented. Charge and dipole values for monomers and dimers as well as polymerized forms of these proteins are summarized. Continuum approximations for cable equations describing actin filaments and microtubules compare favorably to measurements in buffer solutions showing soliton waves and transistor-like amplification of ionic signals, respectively. AC Conductivity and capacitance of tubulin and microtubules have been measured and modeled in the range of frequencies between 100 kHz and 1 MHz. A dramatic change in conductivity occurs when tubulin forms microtubules. In living cells, this signals a conductive phase transition coinciding with mitosis in dividing cells. This process is allowed by TTField penetration into the cleavage furrow in dividing cells and provides the most significant mechanistic explanation of the observed effects. We provide estimates of the forces, energies and power involved in the action of TTFields on microtubules and kinesin motors. These calculations are compared and contrasted with typical values experienced at a cell level and provide strong arguments for real physical effects of TTFields in dividing cells. We also show results of DLS and TEM measurements on microtubules and tubulin oligomers in solution, which allow us to quantify these processes under controlled conditions. In conclusion, the most likely candidates to provide a quantitative explanation of these effects are ionic condensation waves around microtubules as well as dielectrophoretic effects on the dipole moments of microtubules.
Abstract 18984: Impact of Functional vs. Organic Baseline Mitral Regurgitation on Short- and Long-Term Outcomes Following Transcatheter Aortic Valve Replacement
Authors: Sarkis Kiramijyan, Edward Koifman, Federico M Asch, Marco A Magalhaes, Ricardo O Escarcega, Nevin C Baker, Romain Didier, Smita I Negi, Sa'ar Minha, Zachary D Jerusalem, Won Yu Kang, Michael J Lipinski, Rebecca Torguson, Jiaxiang Gai, Petros Okubagzi, Zuyue Wang, Itsik Ben-Dor, Lowell F Satler, Augusto D Pichard, Ron Waksman
Journal: Circulation (2015)

Introduction: The impact of the specific etiology of mitral regurgitation (MR) on outcomes in the TAVR population has not been previously studied. Hypothesis: Functional MR improves to a greater degree than organic MR after relief of the aortic gradient. Methods: The complete TAVR population from May 2007 through May 2015, who had TTE assessments of MR at baseline, was retrospectively analyzed. The TTEs were rigorously evaluated on a de-novo basis in regard to the left-ventricular function, MR etiology, severity, and mitral valve anatomy at multiple intervals including: pre- &amp; post-procedure, 30-days, 6-months, 1-, 2-, and 3-years follow-up. Only patients with baseline ≥moderate MR were selected for this study and further divided into two groups; functional vs. organic etiology. Longitudinal, mixed-model statistical analyses were performed to assess the differences in the degree of longitudinal changes. Results: A total of N=70 patients (44% male, mean 82 years) with ≥moderate MR at baseline including n=30 functional vs. n=40 organic MR. There were no significant differences in the baseline, procedural or in-hospital parameters. The primary outcome of mortality were similar at 30-days (10% vs. 17.5%, p=0.498) and 1-year (26.7% vs. 22.5%, p=0.687) in the functional vs. organic groups, respectively. The secondary outcomes demonstrated significant differences in the longitudinal changes including: greater degrees of improvement in MR severity, LVEF, and NYHA class in the functional vs. the organic MR groups at up to 3-years follow-up (figure). Conclusions: Although the etiology of significant baseline MR in patients undergoing TAVR does not have an impact on 30-days or 1-year mortality, in patients with functional MR, there are greater degrees of short- and long-term improvement of MR severity, LV positive remodeling and functional class. These findings may help strategize therapies for MR in patients with aortic and mitral disease who are undergoing TAVR.
Abstract 21236: Novel Immune Regulatory Defects Contribute to Abdominal Aortic Aneurysm Formation
Authors: Linden A Green, Michael P Murphy, Clifford M Babbey
Journal: Circulation (2017)

Abdominal aortic aneurysm (AAA) is a significant and serious health problem with an incidence as high as 9% and is associated with 15,000 deaths each year in the U.S. Recently AAA has increasingly been considered to be an autoimmune disease, where a pro-inflammatory cascade with cytotoxic and proteolytic features results aortic wall degradation and aneurysm formation, but the underlying causes of this imbalance remain unknown. Regulatory T cells prevent both the activation and effector function of reactive T cells sensitized to auto-antigens. Critical in this process are Type 1 regulatory T-cells (Tr1) which are antigen-specific and identified by expression of CD49b and lymphocyte activation gene 3 (LAG-3). Tr1 cells exhibit strong immunosuppressive activity and are able to restore tolerance in several immune-mediated diseases, through the secretion of high amounts of IL-10. Most importantly IL-10 is essential in the induction as well as immune suppressor activity of Tr1 cells. We found that AAA patients have a decreased number of Tr1 cells compared to risk-factor matched controls, and that those cells are functionally defective, producing reduced levels of IL-10 and having impaired immune suppression abilities. Moreover, naive CD4+ T cells from AAA patients were resistant to Tr1 induction in vitro , and AAA plasma likewise impaired the induction of Tr1 cells from healthy CD4+ T cells. Plasma miRNA analysis revealed a profile of expression changes in AAA patients that inhibit IL-10 expression. Together, these results suggest a critical defect of Tr1 cells in AAA, driven by impaired IL-10 expression, which could contribute to AAA disease pathology.
Complement C3aR Inactivation Attenuates Tau Pathology and Reverses an Immune Network Deregulated in Tauopathy Models and Alzheimer’s Disease
Authors: Alexandra Litvinchuk, Ying-Wooi Wan, Dan B. Swartzlander, Fading Chen, Allysa Cole, Nicholas E. Propson, Qian Wang, Bin Zhang, Zhandong Liu, Hui Zheng
Journal: Neuron (2018)
RDNA-01. microRNA DEGRADATION MEDIATED GENETIC HETEROGENEITY AS A NOVEL MECHANISM FOR TEMOZOLOMIDE RESISTANCE IN GLIOBLASTOMA
Authors: Valya Ramakrishnan, Johnny Akers, Thien Nguyen, Ying Mao, Masayuki Nitta, Jiang Tao, Bob Carter, Clark Chen
Journal: Neuro-Oncology (2018)

Temozolomide (TMZ), the standard-of-care chemotherapy for glioblastoma, is a DNA alkylating drug. At cytotoxic doses, TMZ Induces high levels of alkylated DNA, including O6 methyl-guanine (O6MG), ultimately triggering cell death. In sub-lethal levels, O6MGs undergo non-Watson-Crick pairing, facilitating mutagenesis and promote acquired resistance. Whether the cytotoxic or mutagenic effects of TMZ predominate is largely determined by the DNA repair enzyme, Methyl-guanine-methyl transferase (MGMT). MGMT restores TMZ-alkylated DNA into its native form. To date, studies of MGMT have largely focused on its expression in large populations of cells. Variation of MGMT expression at a single cell level and pertinence of this variation to acquired TMZ resistance remains poorly understood. In single cells derived from the same patient-derived glioblastoma line, we found that the cell-to-cell variability in MGMT mRNA expression differed by as much as 10-fold. The distribution of single cell MGMT expression approximated that of a normal distribution. Upon treatment with TMZ, the mean expression of MGMT increased by two-fold. Additionally, TMZ treatment increased the standard deviation of the MGMT expression distribution by ten-fold, causing significant “widening” of the range the MGMT expression. Both of these effects were caused by degradation of miR-181d, an MGMT suppressing miRNA. TMZ treatment triggered the activation of ATM- and Rad3- related (ATR) kinase, which in turn activated Polyribonucleotide nucleotidyltransferase 1 (PNPT1), an RNAse that ultimately degradation of miR-181d. Our results suggest that RNA degradation enhanced stochastic variation in MGMT expression, allowing a wider range of MGMT expression from which the optimally fit clone can emerge. This novel form of TMZ resistance can be suppressed by over-expression of miR-181d, suggesting the potential of microRNA delivery as a therapeutic strategy. Accordingly, miR-181d delivery combined with TMZ treatment effectively cured intracranial murine models of patient derived glioblastoma xenografts (PDX) that expressed high levels of MGMT.
Abstract 17531: Complete Blood Substitute for Massive Transfusion in Thrombocytopenic and Hemorrhagic Shock Rabbits
Authors: Kohsuke Hagisawa, Manabu Kinoshita
Journal: Circulation (2017)

Introduction: We developed a Hemoglobin vesicle (HbV) and a fibrinogen γ-chain (dodecapeptide HHLGGAKQAGDV, H12)-coated, adenosine-diphosphate (ADP)-encapsulated liposomes [H12-(ADP)-liposomes], wh...
PDTM-12. DLX2 TRANSCRIPTIONAL REGULATION OF CENTRAL NERVOUS SYSTEM CELL FATE RELEVANCE TO PEDIATRIC DIFFUSE MIDLINE GLIOMAS WITH HISTONE 3 MUTATIONS
Authors: Mikaela Nevin, Xiaohua Song, Oren Becher, D Alan Underhill, Roseline Godbout, David Eisenstat
Journal: Neuro-Oncology (2018)

Diffuse intrinsic pontine glioma (DIPG) is refractory to current therapy with less than 2% long term survivors. The identification of histone H3.1/H3.3 K27M mutations in most DIPG has provided new insights into the biology of this fatal disease. The DLX homeobox genes are expressed in the developing forebrain. The Dlx1/Dlx2 double knockout (DKO) mouse loses tangential GABAergic interneuron migration to the neocortex. We have identified genes that encode glutamic acid decarboxylase (GAD) enzymes as direct transcriptional targets of DLX1/DLX2. In DIPG patients with H3.3 K27M mutations there is decreased Dlx2 and increased expression of the myelin transcription factor, Myt1. There is loss of H3 K27 tri-methylation (me3) expression in many tumors with K27M mutations. METHODS AND We used bioinformatics approaches and chromatin immunoprecipitation (ChIP) assays to identify Olig2, Nkx2.2 and Myt1 promoter sequences as candidate DLX2 targets in vivo. DNA binding specificity was confirmed by gel shift assays in vitro. The functional consequences of Dlx2 co-expression with reporter constructs of ChIP-isolated promoter fragments of Olig2 and Nkx2.2 demonstrated repression of gene targets in vitro. qPCR showed increased Olig2 and Nkx2.2 expression in the DKO forebrain. Stable transfection of Dlx2 into a murine DIPG (mDIPG) cell line with the K27M mutation resulted in increased expression of Gad1 and Gad2 and decreased expression of Olig2 and Nkx2.2. Dlx2 stable transfection also resulted in decreased migration, invasion and colony number and size in vitro. Of significance, we demonstrated decreased expression of H3.3 K27M and restoration of H3.3 K27me3 expression in Dlx2 stable transfected mDIPG cells. CONCLUSIONS: DLX transcription factors promote GABAergic interneuron and concomitant inhibition of oligodendroglial differentiation in neural progenitors by repression of a suite of genes including Olig2 and Nkx2.2. Restoration of H3 K27me3 expression in DIPG provides a promising lead towards exploration of differentiation as a therapeutic strategy for DIPG.
CADD-15. TRANSLATIONAL DISCOVERY OF THERAPEUTIC TARGETS FOR GLIOBLASTOMA
Authors: Maria-Magdalena Georgescu, Yan Li, Mohammad Zahid Islam, Jennifer Molina
Journal: Neuro-Oncology (2018)

Glioblastoma is a deadly brain tumor with a median survival of 1.3 years after surgery, radiotherapy and chemotherapy. The dismal prognosis is due to the propensity of the tumor to invade adjacent normal brain. Although next generation sequencing (NGS) led to genomic landscaping of glioblastoma, there is little insight into the mechanism of neoplastic cell invasion, the detection of the invasive cells or their therapeutic targeting. To address these critical issues, we developed a murine model of invasive glioblastoma that mimics the human disease. Using a cancer stem-cell like human glioblastoma cell line in an orthotopic model, we isolated pairs of neoplastic cells growing either in the core of the tumor, or away for the core, in invasive secondary foci. A phenotypic assessment showed significantly decreased animal survival, increased cancer stemness and invasion in the invasive cells in comparison to core cells. Expression profiling of Core and Inv cells resulted in the identification of differentially expressed gene targets controlling metabolic pathways, cell-cell and cell-matrix adhesion and cell differentiation. A 300 gene library, including these targets, was designed for NGS of high grade diffuse glioma cases. In a series of 4 pediatric and adult WHO grade IV diffuse glioma autopsy cases with a total of 28 sequenced distinct primary and secondary tumor foci, as well as normal brain, we found mutations in several of the genes identified in the mouse model. Two categories of novel targets potentially relevant for therapy were confirmed and further addressed: extracellular matrix proteases and metabolic enzymes. These translational findings and the implications for the molecular diagnosis and therapy of glioblastoma will be discussed.
CD117-Amanitin Antibody Drug Conjugates Effectively Deplete Human and Non-Human Primate HSCs: Proof of Concept As a Targeted Strategy for Conditioning Patients for Bone Marrow Transplant
Authors: Bradley R Pearse, Sean M McDonough, Jennifer L Proctor, Rajiv Panwar, Ganapathy Sarma, Molly A McShea, Lena Kien, Junia Dushime, Hillary L Adams, Sharon L. Hyzy, Melissa L. Brooks, Rahul Palchaudhuri, Qing Li, Nathan M Kallen, Pranoti Sawant, Charlotte F McDonagh, Anthony E. Boitano, Michael P. Cooke
Journal: Blood (2018)
IMMU-33. TARGETED IMMUNE CHECKPOINT INHIBITORS FOR INTRATUMORAL DELIVERY IN GBM
Authors: Stephanie Sanders, Denise Herpai, Waldemar Debinski
Journal: Neuro-Oncology (2018)

T cells infiltrate most of solid tumors, however, in glioblastoma (GBM) the presence of these cells is heterogeneous. Using CD3 staining, we find areas of GBM tumors with very few, if any, of these immune cells or few areas that have their dense presence. Immune checkpoint inhibitors (ICI) have yet to produce clinically meaningful responses in patients with GBM. The lack of responses may be related to the limited overall presence of T cells in GBM or inefficient intratumoral trafficking of peripherally ICI-activated cells. In our strategy to make ICI more specific and more accessible to GBM tumors we redirect them to GBM tumor cells to deliver them loco-regionally. IL-13.E13K is a high affinity mutant of interleukin 13 (IL-13), preserving the binding to the cytokine’s receptor alpha 2 (IL-13R2A), which is highly over-expressed on GBM cells. We have constructed two recombinant antibodies. The first consists of a single chain Fv (scFv) region of anti-CTLA-4 antibody, combined with an Fc region of human IgG1 and with IL-13.E13K (termed αCTLA4-Fc-IL-13.E13K). The second consists of the same components but with anti-PD-1 scFv instead of the αCTLA-4 (termed αPD1-Fc-IL13.E13K). Both fusion protein ICIs demonstrated competition for the IL-13R2A. In addition, the redirected immune checkpoint inhibitor αCTLA4-Fc-IL13.E13K demonstrated similar binding to CTLA-4 as did αCTLA4 antibody with Kd values in the low nM range. The αPD1-Fc-IL13.E13K, also demonstrated similar binding affinity to PD-1 as did αPD1 antibodies with Kd values also in the low nM range. Thus, αCTLA4-Fc-IL13.E13K and αPD1-Fc-IL13.E13K redirected to tumor ICI have a strong affinity for the IL-13R2A while continuing to demonstrate strong affinities for CTLA-4 and PD-1. These constructs in conjunction with other immune system stimulations like cytotoxic therapies have the potential to be effective in facilitating the interaction between T cells and GBM tumor cells directly in a tumor microenvironment.
Down regulation of androgen receptor (AR) and its target gene (PSA) expressions by B-DIM leads to sensitization of prostate cancer cells to Taxotere-induced apoptosis.
Journal: Cancer Research (2005)

466  Despite initial response to androgen deprivation, patients with prostate cancer usually develop hormone refractory metastasis and eventually succumb to the disease. Therefore, new therapeutic strategies are urgently needed to overcome drug resistance for the treatment of prostate cancer. Epidemiological studies have shown that the consumption of cruciferous vegetables is associated with reduced cancer risk. 3,3’-diindolymethane (DIM) is an acid condensation product of I3C, which is present in almost all members of the cruciferous vegetable family. DIM has been shown to down-regulate AR, suggesting the growth inhibitory effects of DIM on hormone related cancers. A formulated DIM (B-DIM, BioResponse) has been shown to exhibit approximately 50% higher bioavailability. However, no molecular studies have been reported to date to elucidate the effect of B-DIM on prostate cancer cells. To investigate the effects of B-DIM on prostate cancer cells, we treated hormone sensitive LNCaP cells and hormone insensitive PC-3 cells with 0 to 60 μM of B-DIM for one to three days. MTT, ELISA, and Western blot analysis were conducted to test cell growth inhibition, apoptosis, and the expression of AR and prostate specific antigen (PSA). Microarray analysis was also conducted to assess global alternations in gene expression profile. We found that B-DIM inhibited the growth of prostate cancer cells and induced apoptosis in a dose and time dependent manner. Microarray gene expression analysis showed that B-DIM regulated the expression of genes which are critical for the control of cell growth and apoptosis. Western blot analysis showed that B-DIM significantly inhibited AR and PSA protein expression in LNCaP prostate cancer cells. It has been recently reported that increases in androgen receptor mRNA and proteins are both necessary and sufficient to convert prostate cancer from a hormone-sensitive to a hormone refractory stage, suggesting that over-expression of AR is an important factor for acquired resistance of prostate cancer to hormone ablation therapy. Since our results showed decreased AR and PSA expression with concomitant inhibition of cell growth and induction of apoptosis by B-DIM, we suggest that the resistance acquired by prostate cancer cells to androgen ablation therapy could be reversed by B-DIM treatment. Moreover, we tested our hypothesis whether B-DIM could sensitize hormone insensitive PC-3 prostate cancer cells to Taxotere. We found that Taxotere (1 nM) in combination with 50 μM B-DIM exerted significantly more growth inhibitory effects compared to Taxotere or B-DIM treatment alone. In conclusion, our results provide a solid foundation for devising novel therapeutic strategies for the treatment of hormone or chemo-resistant metastatic prostate cancer by including B-DIM, a non-toxic agent, with other therapeutic agents.