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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-9-5
pubmed:abstractText
High-grade gliomas release excitotoxic concentrations of glutamate which contributes to their malignant phenotype. To improve our understanding of the mechanisms by which glutamate enhances tumor growth and invasion, we examined alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-mediated signaling in glioma cell lines. shRNA was used to stably knockdown GluR1, the most abundant AMPA receptor subunit in glioma, to evaluate its role in tumor signaling, proliferation and tumorigenicity. In a tissue array, there was a statistically significant increase in GluR1 expression in glioblastoma samples compared to anaplastic astrocytoma and low-grade tumors. In vitro, we observed a time and dose-dependent increase in MAPK phosphorylation following exposure to AMPA, which was blocked with AMPA receptor antagonists and the MEK1 inhibitor PD98059. Retroviral delivery of GluR1 shRNA in U251 and U87 glioma cells reduced GluR1 protein expression, inhibited AMPA-mediated increases in MAPK phosphorylation, and decreased glioma proliferation in vitro. U251 and U87 shGluR1 cells implanted into the flanks of nude mice grew slower than controls, which correlated with a decrease in proliferation measured by Ki-67 staining and an increase in apoptosis. These results suggest that AMPA receptors are abundantly expressed in high-grade gliomas and gene silencing of the GluR1 AMPA receptor subunit results in abrogation of AMPA-mediated signaling and tumor growth.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0167-594X
pubmed:author
pubmed:issnType
Print
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
121-33
pubmed:meshHeading
pubmed-meshheading:18317690-Animals, pubmed-meshheading:18317690-Brain Neoplasms, pubmed-meshheading:18317690-Carcinogenicity Tests, pubmed-meshheading:18317690-Cell Cycle, pubmed-meshheading:18317690-Cell Line, Tumor, pubmed-meshheading:18317690-Cell Proliferation, pubmed-meshheading:18317690-Down-Regulation, pubmed-meshheading:18317690-Gene Expression Regulation, pubmed-meshheading:18317690-Glioma, pubmed-meshheading:18317690-Humans, pubmed-meshheading:18317690-Ki-67 Antigen, pubmed-meshheading:18317690-Mice, pubmed-meshheading:18317690-Mice, Nude, pubmed-meshheading:18317690-Microarray Analysis, pubmed-meshheading:18317690-RNA, Double-Stranded, pubmed-meshheading:18317690-RNA, Small Interfering, pubmed-meshheading:18317690-RNA Interference, pubmed-meshheading:18317690-Receptors, AMPA, pubmed-meshheading:18317690-Signal Transduction
pubmed:year
2008
pubmed:articleTitle
Knockdown of GluR1 expression by RNA interference inhibits glioma proliferation.
pubmed:affiliation
Brain Tumor Center, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. jdegroot@mdanderson.org
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't