Quantitative hypermethylation of NMDAR2B in human gastric cancer.
NMDA receptor Type 2B (NMDAR2B) is a candidate TSG first identified in esophageal squamous cell carcinoma (ESCC). To evaluate NMDAR2B methylation in gastric cancer progression, we performed quantitative methylation-specific PCR (MSP), RT-PCR and immnunohistochemistry (IHC) in primary gastric tissues and colony formation assays in gastric cancer cell lines. We found that the expression of NMDAR2B was reactivated by the demethylating agent, 5-aza-2'-deoxycytidine, with or without trichostatin A in gastric cancer cell lines. Moreover, inactivation of NMDAR2B was found to be closely correlated with promoter methylation status in gastric cell lines and primary gastric tumors. IHC data also showed that NMDAR2B was specifically expressed in gastric epithelial cells and its expression was diminished or absent in gastric cancer epithelium. Quantitative analysis of NMDAR2B promoter methylation showed 61% (17/28) hypermethylation in primary gastric tumors versus 5% (1/20) in normal gastric tissues from nongastric cancer patients. Forced over-expression of NMDAR2B in gastric cancer cell lines significantly inhibited cell colony formation. Taken together, the above results suggest that NMDAR2B methylation is a common and important biologically relevant event in gastric cancer progression.
Liu
Jun-Wei
JW
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Kim
Myoung Sook
MS
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Nagpal
Jatin
J
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Yamashita
Keishi
K
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Poeta
Luana
L
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Chang
Xiaofei
X
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Lee
Juna
J
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Park
Hannah Lui
HL
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Jeronimo
Carmen
C
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Westra
William H
WH
Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD.
Mori
Masaki
M
Department of Surgical Oncology, Medical Institute of Bioregulation, Kyushu University, Tsurumibaru, Beppu, Japan.
Moon
Chulso
C
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Trink
Barry
B
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
Sidransky
David
D
Department of Otolaryngology, Division of Head and Neck Cancer Research, Johns Hopkins University School of Medicine, Baltimore, MD.
D014408:Biomarkers, Tumor; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019175:DNA Methylation; D015536:Down-Regulation; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006262:Health; D006801:Humans; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics* / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
D014408:Biomarkers, Tumor; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate