Semi-quantitative detection of GADD45-gamma methylation levels in gastric, colorectal and pancreatic cancers using methylation-sensitive high-resolution melting analysis.
OBJECTIVE
GADD45 is a family of proteins involved in DNA damage response and cell growth arrest. GADD45G was identified as an interleukin-2-induced immediate-early gene, and methylation of GADD45G was studied in various tumor cell lines and a few primary tumor samples. High-resolution melting (HRM) analysis has been used as a novel tool for analysis of promoter methylation.


METHODS
In our study, we used HRM analysis to detect the methylation levels of GADD45G gene in 100 gastric cancers, 100 colorectal cancers, 70 pancreatic cancers and equal number of adjacent normal tissues.


RESULTS
The frequency of GADD45G methylation in all three types of cancers was significantly higher than that in normal tissues. Consistent with previous reports, expression levels of GADD45G were inversely correlated with methylation levels. But we did not find significant association between GADD45G methylation status and TNM staging in all three types of cancers.


CONCLUSIONS
In summary, application of HRM analysis to large amount of clinical samples proves to be a fast and high-throughput way to investigate the epigenetic status of GADD45G. And this is the first study to evaluate the prevalence of GADD45G methylation based on large amount of tumor samples, showing that epigenetic regulation of GADD45G was associated with carcinogenesis.
Zhang
Wei
W
JNU-HKUST Joint Lab, Jinan University, Guangdong, China.
Li
Tianrun
T
Shao
Yong
Y
Zhang
Chao
C
Wu
Qi
Q
Yang
Hong
H
Zhang
Jie
J
Guan
Ming
M
Yu
Bo
B
Wan
Jun
J
D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004249:DNA Damage; D019175:DNA Methylation; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic; D014644:Genetic Variation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008745:Methylation; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012334:RNA, Neoplasm / Q000235:genetics; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D000097642:GADD45 Proteins
D017931:DNA Primers; D004273:DNA, Neoplasm; D047908:Intracellular Signaling Peptides and Proteins; D012334:RNA, Neoplasm; C485654:GADD45G protein, human; D000097642:GADD45 Proteins