Promoter hypermethylation of a novel gene, ZHX2, in hepatocellular carcinoma.
We used methylation-sensitive restriction fingerprinting (MSRF) to identify novel CpG (5'-CG-3' palindrome; p, phosphate group)-rich sequences that are methylated differentially between the hepatocellular carcinoma (HCC) genomes and adjacent nontumorous liver tissues. A 199-base-pair sequence methylated in HCC tumor tissue was isolated and showed high homology to the 5' CpG island of the zinc fingers and homeoboxes protein 2 (ZHX2) gene. By using bisulfite sequencing, we confirmed that hypermethylation of the 5' CpG island of ZHX2 occurred in some HCC and HepG2 cell lines but not in 6 normal liver tissue samples. By using methylation-specific polymerase chain reaction, we detected methylation of the 5' CpG island of ZHX2 in 46.9% of the HCCs. Reverse transcription-polymerase chain reaction demonstrated that ZHX2 messenger RNA (mRNA) was expressed in all 6 normal liver tissue samples but in only 13.3% of the methylated HCCs. Treatment of HepG2 with 5-aza-deoxycytidine could demethylate the promoter and increase ZHX2 mRNA expression. These results suggest that hypermethylation-mediated silencing of ZHX2 is an epigenetic event involved in HCC.
Lv
Zili
Z
Department of Pathology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, People's Republic of China.
Zhang
Meng
M
Bi
Jiong
J
Xu
Fangping
F
Hu
Shaowei
S
Wen
Jianming
J
D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D004273:DNA, Neoplasm; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D014157:Transcription Factors; C476826:ZHX2 protein, human