Citations

BackgroundBivalirudin may be an effective anticoagulation alternative to heparin as anticoagulant agent in percutaneous transcatheter aortic valve interventions (PAVI). We aimed to compare safety and efficacy of bivalirudin versus heparin as the procedural anticoagulant agent in patients undergoing PAVI.MethodsWe conducted an electronic database search of all published data. The primary efficacy endpoints were all‐cause mortality, cardiovascular mortality, myocardial infarction, and stroke. Safety endpoints include major and life‐threatening bleed according to VARC and BARC bleeding, blood transfusion, vascular complications, and acute kidney injury. Odds ratios (OR) and 95% confidence intervals (CI) computed using the Mantel‐Haenszel method.ResultsThree studies (n = 1690 patients) were included, one randomized trial and two observational studies. There was a significant difference favoring bivalirudin over heparin for myocardial infarction (OR 0.41, 95%CI 0.20‐0.87). There was no significant difference in all‐cause mortality at 30 days (OR 0.97, 95%CI 0.62‐1.52), cardiovascular mortality (OR 1.03, 95%CI 0.52‐2.05), stroke (OR 1.23, 95%CI 0.62‐2.46), vascular complications (OR 0.96, 95%CI 0.70‐1.32), acute kidney injury (OR 1.03, 95%CI 0.53‐2.00), blood transfusion (OR 0.67, 95% CI 0.45‐1.01), major and life‐threatening bleed (OR 0.74, 95%CI 0.37‐1.49), and BARC bleeding (OR 0.52, 95%CI 0.23‐1.18).ConclusionsIn patient undergoing aortic valve interventions, no difference was seen between the use of bivalirudin and heparin as the procedural anticoagulant agent, except for a significant lower myocardial infarction events when bivalirudin was used. Further large randomized trials are needed to confirm current results.

Abstract Cancer has been considered a heterogeneous disease, which mainly arises from the accumulation of genetic mutations, leading to a loss of tumor suppressor genes, as well as to an activation of oncogenes. The epigenetic mechanisms, such as DNA and histone modifications, are processes that regulate gene expression, and an alteration of these can contribute to cancer progression. Methylation on histone 3 lysine 9 (H3K9), in particular di-methyl (H3K9me2), is mainly mediated by the nuclear histone lysine methyltransferase G9a. Preliminary data showed that G9a was overexpressed in aggressive and highly metastatic forms of cancer. However, to date, this pathway has remained unstudied in esophageal adenocarcinoma. Interestingly, epigenetic drugs, such as those that target G9a, have the potential to reverse the adverse effects acquired downstream from genetic mutations, which currently cannot be directly repaired or targeted. In the current study, we utilize BRD4770, an S-adenosylmethionine (SAM) mimetic inhibitor of G9a, to determine the benefits of inhibiting this pathway in the context of esophageal adenocarcinoma. We hypothesize that pharmacological targeting of G9a by BRD4770 inhibits esophageal adenocarcinoma cell growth. To examine G9a-mediated dimethyl histone H3K9 levels in esophageal adenocarcinoma, we performed immunohistochemistry on paraffin-embedded esophageal adenocarcinoma tissues with an H3K9me2 antibody. In order to confirm specificity of BRD4770 in regulating the dimethyl histone H3K9 levels, and thus trimethyl H3K9 levels, in esophageal adenocarcinoma, we treated human esophageal adenocarcinoma cells (SKGT-4) with different doses of BRD4770 at various time points for western blot analysis using antibodies against histone H3K9me2 and H3K9me3. Moreover, we found that treatment of SKGT-4 cells with BRD4770 significantly inhibits cell proliferation by MTS assay, as well as clonogenic survival. Therefore, to determine the mechanism(s) by which BRD4770 inhibits the growth of esophageal adenocarcinoma cells, we utilized Caspase-3, Senescence, and Autophagy Assays. Our data shows that inhibition of G9a by BRD4770 does not induce Caspase 3 activity, while it significantly increases senescence and autophagy. Combined, our results suggest that BRD4770 has an important pharmacological role in regulating methyl histone H3K9 levels that may lead to inhibition of esophageal adenocarcinoma cell growth via an increase in senescence and autophagy. Further studies are focused on in vivo models to understand these effects in more detail, however the fact that an anti-G9a drug antagonizes esophageal adenocarcinoma cell growth raises optimism for its potential in the treatment of this malignancy. Note: This abstract was not presented at the meeting. Citation Format: Mabel G. Perez-Oquendo, Gwen A. Lomberk, Raul A. Urrutia, Sarah Kossak, Navtej Buttar, Sounak Gupta. Treatment with the G9a antagonist, BRD4770, inhibits esophageal adenocarcinoma cell growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-094. doi:10.1158/1538-7445.AM2017-LB-094

Abstract Archival tumor samples present a rich resource of annotated specimens for genomics research. However, standard variant calling approaches require a matched normal sample from the same individual, which is often not available with archival tissue. Without a matched normal sample, it is very difficult to distinguish between true somatic variants and germline variants that are private to the individual. Archival FFPE sections often contain adjacent normal tissue, but this normal tissue is often contaminated with infiltrating tumor cells. Comparative somatic variant callers are designed to exclude variants present in the normal sample, so a novel approach is required to leverage sequencing of adjacent normal tissue. Here we present LumosVar 2.0, a software package designed to jointly analyze multiple samples from the same patient. The approach is based on the concept that the allelic fraction of somatic variants, but not germline variants, would be diluted by the presence of normal tissue. Given the allele specific copy number state and expected tumor fraction of each sample, one can model the expected allelic fractions of somatic and germline variants. LumosVar estimates allele specific copy number and tumor sample fractions from the data, and uses the model to call somatic and germline variants. LumosVar is also able to detect sub clonal events and spatial heterogeneity between samples. To evaluate this approach, we used a glioblastoma dataset, where enhancing (high tumor content) and non-enhancing (low tumor content) samples were available for each patient, as well as the matched normal sample to define the true somatic variants. We show that both sensitivity and positive predictive value are improved by analyzing the high tumor and low tumor jointly compared to analyzing the samples individually or in silico pooling of the two samples. Finally, we apply this approach to a set of breast and prostate archival FFPE tumor samples where normal samples were not available for germline sequencing. Citation Format: Rebecca F. Halperin, Winnie S. Liang, Erica Tassone, Jonathan Adkins, Megan Russell, Nhan Tran, Nicole Hank, James Newell, Sandeep Gupta, Michael Berens, Ronald Korn, David W. Craig, Sara A. Byron. Leveraging spatial heterogeneity in tumor purity for improved somatic variant calling of archival tumor-only samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-007. doi:10.1158/1538-7445.AM2017-LB-007

Abstract Mismatch repair (MMR) is essential for temozolomide (TMZ) sensitivity, and MMR deficiency causes TMZ resistance and disease recurrence. However, the role MMR in TMZ response has been linked with Msh2/Msh6 (MutSα), while role of Msh3, a component of MutSβ remains unclear. To delineate role of MutSα and MutSβ in TMZ response, we used siRNA to disrupt MSH6 and MSH3 expression. As expected, silencing of MSH6 led to resistance in a TMZ-sensitive U251 cell line. In contrast, silencing of MSH3 enhanced TMZ sensitivity as compared to the control cells. These results support established role of MutSα in TMZ response via replication stress and DNA double strand breaks (DSB), and reveal that MutSβ may potentially influence TMZ response by modulating DSB repair. Consistently, host cell reactivation (HCR) assays in U251 expressing DRGFP reporter showed decreased homologous recombination (HR) after MSH3 knockdown (KD), while Msh6 KD had no effect on HR efficiency. Supporting the concept of synthetic lethality of HR with PARP inhibition, clinically relevant dose of veliparib (1 µM) showed a modest but consistent increase in TMZ sensitization measured in terms of potentiation factor (PF, ratio of relative growth with TMZ alone/ TMZ and veliparib) in MSH3 KD (PF 1.6±0.2) as compared to control cells (PF 1.1±0.2). Sensitizing effect of 1 µM veliparib in MSH6 KD (PF 1.7±0.5) was comparable to that in MSH3 KD cells. Interestingly, supra-therapeutic dose of veliparib (10 µM) induced more pronounced sensitization in MSH6 KD cells (PF 2.6±0.3) as compared to MSH3 KD (PF 2.4±0.3) or control cells (PF 1.6±0.2). Consistently, veliparib (10 µM) alone had no impact on DNA damage signaling, while TMZ induced prominent increase in phosphorylation of KAP1, Chk1 and Chk2 in control and MSH3 KD cells, but not in MSH6 KD cells; veliparib/TMZ co-treatment led a robust signaling in all 3 types of cells. Increased sensitization by veliparib after MSH3 KD was also examined in a TMZ-resistant (GBM22TMZ) PDX model carrying resistance due to a homozygous mutation in MSH6, and a 4-fold increase in HR efficiency. In clonogenic assays silencing of MSH3 or BRCA1 had no effect on TMZ sensitivity in GBM22TMZ cells. However, veliparib alone (10 µM) decreased colony formation with relative colony formation 0.54±0.03 and 0.32±0.06 in MSH3 and BRCA1 KD cells, respectively as compared to 0.82±0.04 in controls. TMZ/veliparib co-treatment in GBM22TMZ led to further decrease in colony formation in MSH3 KD and BRCA1 KD cells with relative colony formation of 0.30±0.04 and 0.19±0.02, respectively versus 0.46±0.03 in control. Taken together, our results suggest that MutSα and MutSβ differentially regulate cytotoxic effects of TMZ. Decreased HR efficiency and enhanced sensitizing effects of veliparib in MSH3 KD cells partially define synthetic lethality of MMR deficiency with PARP, and may help development of PARP inhibitors as sensitizer of TMZ therapy in GBM. Citation Format: Shiv K. Gupta, Emily J. Smith, Ann M. Tuma, Brett L. Carlson, Mark A. Schroeder, Gasper J. Kitange, Jann N. Sarkaria. MutSα and MutSβ mismatch repair complexes differentially regulate temozolomide efficacy & sensitizing effects of veliparib in glioblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1109. doi:10.1158/1538-7445.AM2017-1109

AbstractBackgroundTranscatheter aortic valve replacement (TAVR) is typically performed under general anesthesia (GA). However, there is increasing data supporting the safety of performing TAVR under local anesthesia/conscious sedation (LA). We performed a meta‐analysis to gain better understanding of the safety and efficacy of LA versus GA in patients with severe aortic stenosis undergoing TAVR.Methods and ResultsWe comprehensively searched EMBASE, PubMed, and Web of Science. Effect sizes were summarized using risk ratios (RRs) difference of the mean (DM), and 95% CIs (confidence intervals) for dichotomous and continuous variables respectively. Twenty‐six studies and 10,572 patients were included in the meta‐analysis. The use of LA for TAVR was associated with lower overall 30‐day mortality (RR, 0.73; 95% CI, 0.57–0.93; P = 0.01), use of inotropic/vasopressor drugs (RR, 0.45; 95% CI, 0.28–0.72; P < 0.001), hospital length of stay (LOS) (DM, −2.09; 95% CI, −3.02 to −1.16; P < 0.001), intensive care unit LOS (DM, −0.18; 95% CI, −0.31 to −0.04; P = 0.01), procedure time (DM, −25.02; 95% CI, −32.70 to −17.35; P < 0.001); and fluoroscopy time (DM, −1.63; 95% CI, −3.02 to −0.24; P = 0.02). No differences were observed between LA and GA for stroke, cardiovascular mortality, myocardial infarction, permanent pacemaker implantation, acute kidney injury, paravalvular leak, vascular complications, major bleeding, procedural success, conduction abnormalities, and annular rupture.ConclusionOur meta‐analysis suggests that use of LA for TAVR is associated with a lower 30‐day mortality, shorter procedure time, fluoroscopy time, ICU LOS, hospital length of stay, and reduced need for inotropic support.

AbstractElaboration of tumor necrosis factor (TNF) is a very early event in development of ischemia/reperfusion injury pathophysiology. Therefore, TNF may be a prominent mediator of endothelial cell and vascular wall dysfunction in sickle cell anemia, a hypothesis we addressed using NY1DD, S+SAntilles, and SS‐BERK sickle transgenic mice. Transfusion experiments revealed participation of abnormally activated blood monocytes exerting an endothelial activating effect, dependent upon Egr‐1 in both vessel wall and blood cells, and upon NFκB(p50) in a blood cell only. Involvement of TNF was identified by beneficial impact from TNF blockers, etanercept and infliximab, with less benefit from an IL‐1 blocker, anakinra. In therapeutic studies, etanercept ameliorated multiple disturbances of the murine sickle condition: monocyte activation, blood biomarkers of inflammation, low platelet count and Hb, vascular stasis triggered by hypoxia/reoxygenation (but not if triggered by hemin infusion), tissue production of neuro‐inflammatory mediators, endothelial activation (monitored by tissue factor and VCAM‐1 expression), histopathologic liver injury, and three surrogate markers of pulmonary hypertension (perivascular inflammatory aggregates, arteriolar muscularization, and right ventricular mean systolic pressure). In aggregate, these studies identify a prominent—and possibly dominant—role for an abnormal monocyte‐TNF‐endothelial activation axis in the sickle context. Its presence, plus the many benefits of etanercept observed here, argue that pilot testing of TNF blockade should be considered for human sickle cell anemia, a challenging but achievable translational research goal.