Promoter methylation and mRNA expression of DKK-3 and WIF-1 in hepatocellular carcinoma.
OBJECTIVE
To investigate the promoter methylation status and mRNA expression of DKK-3 and WIF-1 gene in hepatocellular carcinoma (HCC).


METHODS
DKK-3 and WIF-1 acted as Wnt-antagonists and tumor suppressors, but hypermethylation of the gene promoter and low mRNA expression activated Wnt signaling aberrantly and induced the development of HCC. Methylation status of the DKK-3 and WIF-1 gene promoter was investigated using methylation specific polymerase chain reaction (PCR) in tumor and adjacent non-cancerous tissues from 33 HCC patients and 20 normal liver tissues served as control. The expression of DKK-3 and WIF-1 mRNA was also determined by real-time quantitative reverse transcriptase PCR. The relationship between methylation, mRNA expression, and clinical data, as well as methylation and mRNA expression of the two genes were analyzed.


RESULTS
The methylation of DKK-3 and WIF-1 genes in HCC increased significantly compared with adjacent non-cancerous tissues and normal control tissues (chi(2) =7.79, P < 0.05; chi(2) = 4.89, P < 0.05), and no significant difference in methylation between adjacent non-cancerous tissues and normal control tissues was observed. In HCC tissues, significant differences in the DKK-3 promoter methylation were observed in age and cirrhosis, and significant differences of the WIF-1 promoter methylation were observed in HBsAg and cirrhosis. The average expression of DKK-3 mRNA in HCC and adjacent non-cancerous tissues was increased significantly compared with normal control tissues. The average expression of WIF-1 mRNA showed no significant difference among the three tissues. The mRNA expression of DKK-3 gene in HCC was decreased as the pathological grade increased.


CONCLUSIONS
The aberrant promoter methylation and decreased expression of DKK-3 and WIF-1 may be an important mechanism in HCC, and may be a far-reaching significance in early diagnosis and therapy of HCC.
Ding
Zhen
Z
Department of Surgery, First Affiliated Hospital of Anhui Medical University, 218 Jixi avenue, Hefei 230022, Anhui province, China.
Qian
Ye-Ben
YB
Zhu
Li-Xin
LX
Xiong
Qi-Ru
QR
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism; D018925:Chemokines; D002648:Child; D019175:DNA Methylation; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D055815:Young Adult
D048868:Adaptor Proteins, Signal Transducing; D018925:Chemokines; C498624:DKK3 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C485569:WIF1 protein, human; D051153:Wnt Proteins