[Mechanism of loss of human esophageal cancer-related gene 4 (ECRG4) gene expression in esophageal squamous cell carcinoma cell line EC9706].
OBJECTIVE
To investigate the mechanism of loss of human esophageal cancer-related gene 4 (ECRG4) expression in esophageal squamous cell carcinoma (ESCC.)


METHODS
PCR-SSCP and DNA sequencing analysis were used to detect the mutation of ECRG4 exons in esophageal cancer and matched adjacent normal tissues of 80 patients. DNA bisulfite-modifying ssPCR sequencing assay was used to examine the methylation status of ECRG4 promoter in human esophageal squamous cell carcinoma EC9706 cells. The re-expression of ECRG4 mRNA was examined by RT-PCR in EC9706 cells, after treatment with either demethylation drug 5-aza-2'-deoxycytidine or arsenic trioxide.


RESULTS
No mutation in the four ECRG4 exons was found in all the ESCC and matched normal adjacent tissues. RT-PCR showed that 11 of 16 CpG islands of ECRG4 promoter were hypermethylated, while ECRG4 mRNA expression level was undetectable in the EC9706 cells. The ECRG4 mRNA was re-expressed after treatment with either demethylation drug 5-aza-2'-deoxycytidine or arsenic trioxide.


CONCLUSIONS
The epigenetic mechanism of methylation is a reason of loss of ECRG4 gene expression in the ESCC cell line EC9706.
Department of Etiology and Carcinogenesis, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
Lin-Wei
LW
Li
Xi-Ying
XY
Yu
Xiao-Yan
XY
Li
Li-Ping
LP
Guo
Yun
Y
Zhou
Shi-Xin
SX
Lu
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D000077209:Decitabine; D044127:Epigenesis, Genetic; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005091:Exons; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010087:Oxides / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D001152:Arsenicals; C476999:ECRG4 protein, human; D009363:Neoplasm Proteins; D010087:Oxides; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D000077209:Decitabine; D001374:Azacitidine; D000077237:Arsenic Trioxide