N-methyl-D-aspartate receptor type 2B is epigenetically inactivated and exhibits tumor-suppressive activity in human esophageal cancer

Myoung Sook Kim, Keishi Yamashita, Jin Hyen Baek, Hannah Lui Park, Andre Lopes Carvalho, Motonobu Osada, Mohammad Hoque, Sunil Upadhyay, Masaki Mori, Chulso Moon, David Sidransky

Research output: Contribution to journalArticle


Promoter hypermethylation accompanied by gene silencing is a common feature of human cancers. We identified previously several new tumor suppressor genes based on pharmacologic unmasking of the promoter region and detection of reexpression on microarray analysis. In this study, we modified the selection of candidates from our previous microarray data by excluding genes that showed basal expression in cancer cell lines. With the new method, we found novel methylated genes with 90% accuracy. Among these 33 novel methylated genes that we identified in esophageal squamous cell carcinoma (ESCC) cell lines, N-methyl-D-aspartate receptor type 2B (NMDAR2B) was of particular interest. NMDAR2B was methylated in 95% of primary human ESCC tissue specimens and 12 ESCC cell lines by sequence analysis. NMDAR2B expression was silenced in all 12 ESCC cell lines and was reactivated by the demethylating agent 5-aza-2′ -deoxycytidine. Moreover, reintroduction of the gene was accompanied by marked Ca2+-independent apoptosis in ESCC cell lines, suggesting that NMDAR2B can suppress tumor growth. Thus, NMDAR2B promoter methylation is common in ESCC, abrogating gene transcription and leading to cellular resistance to apoptosis.

Original languageEnglish (US)
Pages (from-to)3409-3418
Number of pages10
JournalCancer Research
Issue number7
Publication statusPublished - Apr 1 2006


ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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