Quantitative hypermethylation of NMDAR2B in human gastric cancer (original) (raw)
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Cancer Science, 2006
Materials and Methods Tissue samples, cell lines and 5-aza-dC treatment Ten primary gastric cancer samples (male/female = 7/3, aged 38-81 years) and two normal gastric mucosae were obtained from 10 patients undergoing gastrectomy at Aichi Cancer Center (Nagoya, Japan) with informed consent. These samples were frozen and stored at −80°C until extraction of DNA or RNA. Gastric cancer cell lines AGS, MKN28, MKN45 and KATOIII were obtained from the Japanese Collection of Research Bioresources (Tokyo, Japan) and American Type Culture Collection (Manassas, VA, USA). Two gastric cancer cell lines, HSC44 and HSC57, were gifted by Dr Kazuyoshi Yanagihara at the National Cancer Center Research Institute (Tokyo, Japan). AGS cells were seeded at a density of 3 × 10 5 cells/10 cm dish on day 0 and treated with freshly prepared 1 µM 5-aza-dC (Sigma) for 24 h on days 1, 3 and 5. After each treatment, the cells were placed in fresh medium and harvested on day 6. Genomic DNA was extracted by standard phenol/chloroform procedures. Total RNA was extracted using ISOGEN
Gene methylation profile of gastric cancerous tissue according to tumor site in the stomach
BMC Cancer, 2016
Background: There is considerable information on the methylation of the promoter regions of different genes involved in gastric carcinogenesis. However, there is a lack of information on how this epigenetic process differs in tumors originating at different sites in the stomach. The aim of this study is to assess the methylation profiles of the MLH1, MGMT, and DAPK-1 genes in cancerous tissues from different stomach sites. Methods: Samples were acquired from 81 patients suffering stomach adenocarcinoma who underwent surgery for gastric cancer in the Lithuanian University of Health Sciences Hospital Kaunas Clinics in 2009-2012. Gene methylation was investigated with methylation-specific PCR. The study was approved by the Lithuanian Biomedical Research Ethics Committee. Results: The frequencies of methylation in cancerous tissues from the upper, middle, and lower thirds of the stomach
Oncogene, 2008
N-methyl-D-aspartate receptors (NMDARs) are the predominant excitatory neurotransmitter receptors in the mammalian brain. We found that among the three NMDARs examined (NMDAR1, NMDAR2A, NMDAR2B), only NMDAR2A was silenced in colorectal carcinoma (CRC) cell lines at basal line and reactivated by the demethylating agent, 5-aza-2 0deoxycytidine. NMDAR2A was expressed in normal colon epithelium, while expression was hardly detectable in colon cancer tissues. Promoter methylation of NMDAR2A was confirmed by bisulfite sequencing and combined bisulfite restriction analysis in the CRC cell lines and primary tumors. Quantitative methylation-specific PCR demonstrated NMDAR2A promoter hypermethylation in 82 of 100 primary human CRC, 15 of 100 normal corresponding epithelial tissues and 1 of 11 (9%) normal colon mucosa samples obtained from patients without cancer. Moreover, forced expression of full-length NMDAR2A in CRC cell lines induced apoptosis and almost abolished the ability of the cells to form colonies in culture, while NMDAR2A knockdown increased cell growth. Thus, NMDAR2A is commonly hypermethylated in primary human CRC and possesses tumor-suppressive activity.
Cancer Research, 2006
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-2V-deoxycytidine. Moreover, reintroduction of the gene was accompanied by marked Ca 2+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.
Oncology Reports, 1994
To determine the clinical significance of gene promoter methylation in esophageal squamous cell carcinoma (ESCC), we examined the promoter methylation status of genes showing elevated expression, as determined by DNA microarray-based transcriptomic analysis, in three ESCC cell lines (TE-1, TE-2, TE-10) after 5-aza-2'-deoxycytidine (DAC) treatment. We observed a high degree of DNA methylation within the promoter regions of three genes, namely cathepsin L2 (CTSL2), normal mucosa of esophagus specific 1 (NMES1), and fatty acid binding protein 5 (FABP5). Overexpression of NMES1 in ESCC cell lines increased cell motility. Downregulation of NMES1 might play an important role in the cell motility of ESCC or be a potent marker of malignancy.
Identification of DNA methylation changes associated with human gastric cancer
BMC Medical Genomics, 2011
Background Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult. Methods We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay) in combination with a genome analyzer and a new normalization algorithm. Results We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs), transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those ...
CpG island methylation in premalignant stages of gastric carcinoma
Cancer research, 2001
There are limited reports on methylation analysis of the premalignant lesions of gastric carcinoma thus far. This is despite the fact that gastric carcinoma is one of the tumors with a high frequency of CpG island hypermethylation. To determine the frequency and timing of hypermethylation during multistep gastric carcinogenesis, non-neoplastic gastric mucosa (n = 118), adenomas (n = 61), and carcinomas (n = 64) were analyzed for their p16, human Mut L homologue 1 (hMLH1), death-associated protein (DAP)-kinase, thromobospondin-1 (THBS1), and tissue inhibitor of metalloproteinase 3 (TIMP-3) methylation status using methylation-specific PCR. Three different classes of methylation behaviors were found in the five tested genes. DAP-kinase was methylated at a similar frequency in all four stages, whereas hMLH1 and p16 were methylated in cancer samples (20.3% and 42.2%, respectively) more frequently than in intestinal metaplasia (6.3% and 2.1%, respectively) or adenomas (9.8% and 11.5%, re...
DNA and histone methylation in gastric carcinogenesis
World Journal of Gastroenterology, 2013
Epigenetic alterations contribute significantly to the development and progression of gastric cancer, one of the leading causes of cancer death worldwide. Epigenetics refers to the number of modifications of the chromatin structure that affect gene expression without altering the primary sequence of DNA, and these changes lead to transcriptional activation or silencing of the gene. Over the years, the study of epigenetic processes has increased, and novel therapeutic approaches that target DNA methylation and histone modifications have emerged. A greater understanding of epigenetics and the therapeutic potential of manipulating these processes is necessary for gastric cancer treatment. Here, we review recent research on the effects of aberrant DNA and histone methylation on the onset and progression of gastric tumors and the development of compounds that target enzymes that regulate the epigenome.
The American Journal of Pathology, 2004
We evaluated the significance of aberrant DNA methyltransferase 1 (DNMT1) protein expression during gastric carcinogenesis. The protein expression of DNMT1, Muc2, human gastric mucin, E-cadherin, and proliferating cell nuclear antigen was examined immunohistochemically in gastric cancers and corresponding noncancerous mucosae from 134 patients. The DNA methylation status of the CpG islands of the p16, human MutL homologue 1 (hMLH1), E-cadherin, and thrombospondin-1 (THBS-1) genes and the methylated in tumor (MINT)-1, -2, -12, and -31 clones was examined by methylation-specific polymerase chain reaction and combined bisulfite restriction enzyme analysis. Epstein-Barr virus (EBV) infection was detected by in situ hybridization. Nuclear immunoreactivity for DNMT1 was not detected in any of the noncancerous epithelia, except in proliferative zones (positive internal control), but was found in 97 (72%) of the gastric cancers. DNMT1 overexpression correlated significantly with poorer tumor differentiation (P < 0.001), but not with the phenotype (gastric type versus intestinal type) of the cancer cells. It also correlated significantly with DNA hypermethylation of the CpG islands of the hMLH1 (P ؍ 0.024) and THBS-1 genes (P ؍ 0.043), and with the CpG island methylator phenotype in the gastric cancers (P ؍ 0.007). Reduced E-cadherin expression correlated significantly with poorer tumor differentiation (P ؍ 0.002), DNA hypermethylation of the E-cadherin gene (P < 0.001) and DNMT1 overexpression (P ؍ 0.014). DNMT1 overexpression was also associated with EBV infection (a potential etiological factor in gastric car-
Scientific Reports, 2022
Individual cell types of human tissues have their own CpG site methylation profiles, which might be utilized for the development of methylation markers to denote tumor-infiltrating lymphocytes (TILs). We aimed to develop DNA methylation markers that recapitulate the densities of TILs in gastric carcinoma (GC). Through genome-wide methylation profiling, NCOR2, PARK2, and ZSCAN12 were found to be highly methylated in CD3-positive and CD8-positive cells and rarely methylated in tumor cells. Scores of the three methylation markers were analyzed for their relationship with the overall survival and recurrence-free survival of patients with advanced GC (n = 471). The scores of three methylation markers were closely associated with densities of CD3-positive or CD8-positive cells at the tumor center or invasive front of GCs and found to be a significant prognostic factor in univariate analysis of overall survival and recurrence-free survival. In multivariate analysis, the highest score showe...