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North Bethesda, MD, United States

Sarnaik A.A.,University of Pittsburgh | Conley Y.P.,University of Pittsburgh | Okonkwo D.O.,University of Pittsburgh | Barr T.L.,University of Pittsburgh | And 5 more authors.
Journal of Neurotrauma | Year: 2010

Poly(ADP-ribose) polymerase-1 (PARP-1) plays an important role in the cellular response to stress and DNA damage. However, excessive activity of PARP-1 exacerbates brain injury via NAD+ depletion and energy failure. The purpose of this study was to determine if tagging single nucleotide polymorphisms (tSNPs) covering multiple regions of the PARP-1 gene are related to outcome after traumatic brain injury (TBI) in humans. DNA from 191 adult patients with severe TBI was assayed for four tSNPs corresponding to haplotype blocks spanning the PARP-1 gene. Categorization as favorable or poor outcome was based on Glasgow Outcome Scale (GOS) score assigned at 6 months. PARP-1 enzyme activity was indirectly evaluated by quantifying poly-ADP-ribose (PAR)-modified proteins in cerebrospinal fluid (CSF) using an enzyme-linked immunosorbent assay. In multiple logistic regression analysis controlling for age, initial Glasgow Coma Scale score, and gender, the AA genotype of SNP rs3219119 was an independent predictor of favorable neurologic outcome. This SNP tags a haplotype block spanning the automodification and catalytic domains of the PARP-1 gene. SNP rs2271347 correlated with CSF PAR-modified protein level. This SNP, which did not correlate with outcome, tags a haplotype block spanning the promoter region of the PARP-1 gene. We conclude that after severe TBI in humans, a PARP-1 polymorphism within the automodification-catalytic domain is associated with neurological outcome, while a polymorphism within the promoter region was associated with CSF PAR-modified protein level. These findings must be replicated in a prospective study before the relevance of PARP-1 polymorphisms after TBI can be established. © 2010, Mary Ann Liebert, Inc. Source

Barr T.L.,National Institute of Nursing Research | Barr T.L.,University of California at Los Angeles | Latour L.L.,U.S. National Institutes of Health | Lee K.-Y.,Yonsei University | And 8 more authors.
Stroke | Year: 2010

Background and Purpose: Matrix metalloproteinases (MMP) may play a role in blood-brain barrier (BBB) disruption after ischemic stroke. We hypothesized that plasma concentrations of MMP-9 are associated with a marker of BBB disruption in patients evaluated for acute stroke. Methods: Patients underwent MRI on presentation and ∼24 hours later. The MRI marker, termed hyperintense acute reperfusion injury marker (HARM), is gadolinium enhancement of cerebrospinal fluid on fluid-attenuated inversion recovery MRI. Plasma MMP-9 and tissue inhibitor of matrix metalloproteinase-1 were measured by enzyme-linked immunosorbent assay. Logistic regression models tested for predictors of HARM on 24-hour follow-up scans separately for MMP-9 and the ratio of MMP-9 to TIMP-1. Results: For the 41 patients enrolled, diagnoses were: acute ischemic cerebrovascular syndrome, 33 (80.6%); intracerebral hemorrhage, 6 (14.6%); stroke mimic, 1 (2.4%); and no stroke, 1 (2.4%). HARM was present in 17 (41.5%) patients. In model 1, HARM was associated with baseline plasma MMP-9 concentration (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.001-1.019; P=0.033). In model 2, HARM was associated with the ratio of MMP-9 to tissue inhibitor of matrix metalloproteinase-1 (OR, 4.94; 95% CI, 1.27-19.14; P=0.021). Conclusions:s: Baseline MMP-9 was a significant predictor of HARM at 24-hour follow-up, supporting the hypothesis that MMP-9 is associated with BBB disruption. If the association between MMP-9 and BBB disruption is confirmed in future studies, HARM may be a useful imaging marker to evaluate MMP-9 inhibition in ischemic stroke and other populations with BBB disruption. © 2010 American Heart Association, Inc. Source

Barr T.L.,National Institute of Nursing Research | Conley Y.,University of Pittsburgh | Ding J.,U.S. National Institute on Aging | Dillman A.,U.S. National Institute on Aging | And 4 more authors.
Neurology | Year: 2010

Objective: The objective of this study was to provide insight into the molecular mechanisms of acute ischemic cerebrovascular syndrome (AICS) through gene expression profiling and pathway analysis. Methods: Peripheral whole blood samples were collected from 39 MRI-diagnosed patients with AICS and 25 nonstroke control subjects ≥18 years of age. Total RNA was extracted from whole blood stabilized in Paxgene RNA tubes, amplified, and hybridized to Illumina HumanRef-8v2 bead chips. Gene expression was compared in a univariate manner between stroke patients and control subjects using t test in GeneSpring. The significant genes were tested in a logistic regression model controlling for age, hypertension, and dyslipidemia. Inflation of type 1 error was corrected by Bonferroni and Ingenuity Systems Pathway analysis was performed. Validation was performed by QRT-PCR using Taqman gene expression assays. Results: A 9-gene profile was identified in the whole blood of ischemic stroke patients using gene expression profiling. Five of these 9 genes were identified in a previously published expression profiling study of stroke and are therefore likely biomarkers of stroke. Pathway analysis revealed toll-like receptor signaling as a highly significant canonical pathway present in the peripheral whole blood of patients with AICS. Conclusions: Our study highlights the relevance of the innate immune system through toll-like receptor signaling as a mediator of response to ischemic stroke and supports the claim that gene expression profiling can be used to identify biomarkers of ischemic stroke. Further studies are needed to validate and refine these biomarkers for their diagnostic potential. © 2010 by AAN Enterprises, Inc. Source

Potosky A.L.,Georgetown University | Han P.K.J.,Center for Outcomes Research and Evaluation | Rowland J.,U.S. National Cancer Institute | Klabunde C.N.,U.S. National Cancer Institute | And 6 more authors.
Journal of General Internal Medicine | Year: 2011

Background: The growing number of cancer survivors combined with a looming shortage of oncology specialists will require greater coordination of post-treatment care responsibilities between oncologists and primary care physicians (PCPs). However, data are limited regarding these physicians' views of cancer survivors' care. Objective: To compare PCPs and oncologists with regard to their knowledge, attitudes, and practices for follow-up care of breast and colon cancer survivors. Design and Subjects: Mailed questionnaires were completed by a nationally representative sample of 1,072 PCPs and 1,130 medical oncologists in 2009 (cooperation rate=65%). Sampling and non-response weights were used to calculate estimates to reflect practicing US PCPs and oncologists. Main Measures: PCPs and oncologists reported their 1) preferred model for delivering cancer survivors' care; 2) assessment of PCPs' ability to perform follow-up care tasks; 3) confidence in their knowledge; and 4) cancer surveillance practices. Key Results: Compared with PCPs, oncologists were less likely to believe PCPs had the skills to conduct appropriate testing for breast cancer recurrence (59% vs. 23%, P<0.001) or to care for late effects of breast cancer (75% vs. 38%, P<0.001). Only 40% of PCPs were very confident of their own knowledge of testing for recurrence. PCPs were more likely than oncologists to endorse routine use of non-recommended blood and imaging tests for detecting cancer recurrence, with both groups departing substantially from guideline recommendations. Conclusion: There are significant differences in PCPs' and oncologists' knowledge, attitudes, and practices with respect to care of cancer survivors. Improving cancer survivors' care may require more effective communication between these two groups to increase PCPs' confidence in their knowledge, and must also address oncologists' attitudes regarding PCPs' ability to care for cancer survivors. © 2011 Society of General Internal Medicine. Source

Garimella S.V.,Center for Cancer Research | Garimella S.V.,U.S. National Institutes of Health | Gehlhaus K.,U.S. National Cancer Institute | Dine J.L.,Center for Cancer Research | And 10 more authors.
Breast Cancer Research | Year: 2014

Introduction: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) binds to its receptors, TRAIL-receptor 1 (TRAIL-R1) and TRAIL-receptor 2 (TRAIL-R2), leading to apoptosis by activation of caspase-8 and the downstream executioner caspases, caspase-3 and caspase-7 (caspase-3/7). Triple-negative breast cancer (TNBC) cell lines with a mesenchymal phenotype are sensitive to TRAIL, whereas other breast cancer cell lines are resistant. The underlying mechanisms that control TRAIL sensitivity in breast cancer cells are not well understood. Here, we performed small interfering RNA (siRNA) screens to identify molecular regulators of the TRAIL pathway in breast cancer cells.Methods: We conducted siRNA screens of the human kinome (691 genes), phosphatome (320 genes), and about 300 additional genes in the mesenchymal TNBC cell line MB231. Forty-eight hours after transfection of siRNA, parallel screens measuring caspase-8 activity, caspase-3/7 activity, or cell viability were conducted in the absence or presence of TRAIL for each siRNA, relative to a negative control siRNA (siNeg). A subset of genes was screened in cell lines representing epithelial TNBC (MB468), HER2-amplified breast cancer (SKBR3), and estrogen receptor-positive breast cancer (T47D). Selected putative negative regulators of the TRAIL pathway were studied by using small-molecule inhibitors.Results: The primary screens in MB231 identified 150 genes, including 83 kinases, 4 phosphatases, and 63 nonkinases, as potential negative regulators of TRAIL. The identified genes are involved in many critical cell processes, including apoptosis, growth factor-receptor signaling, cell-cycle regulation, transcriptional regulation, and DNA repair. Gene-network analysis identified four genes (PDPK1, IKBKB, SRC, and BCL2L1) that formed key nodes within the interaction network of negative regulators. A secondary screen of a subset of the genes identified in additional cell lines representing different breast cancer subtypes and sensitivities to TRAIL validated and extended these findings. Further, we confirmed that small-molecule inhibition of SRC or BCL2L1, in combination with TRAIL, sensitizes breast cancer cells to TRAIL-induced apoptosis, including cell lines resistant to TRAIL-induced cytotoxicity.Conclusions: These data identify novel molecular regulators of TRAIL-induced apoptosis in breast cancer cells and suggest strategies for the enhanced application of TRAIL as a therapy for breast cancer. © 2014 Garimella et al.; licensee BioMed Central Ltd. Source

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