Promoter hypermethylation of the ADAM23 gene in colorectal cancer cell lines and cancer tissues.
Promoter hypermethylation of the ADAM23 gene, which is normally involved in cell-to-cell and cell-to matrix adhesion, has been reported in pancreatic, breast and brain cancer, and recently the role of this gene was examined in gastric cancer. In this study, we analyzed ADAM23 expression in colorectal cancer cell lines and examined its methylation by methylation-specific PCR (MSP) and bisulfate-modified DNA sequencing analysis. Methylated cells were treated with 5-aza-2'-deoxycytidine to restore the ADAM23 expression. We then examined ADAM23 methylation status in colorectal cancer tissues and their corresponding normal tissues. We found that ADAM23 was aberrantly silenced or expressed at very low levels in 28 of the 32 (88%) colorectal cancer cell lines. MSP analysis showed that ADAM23 was methylated in 29 of 32 (91%) colorectal cancer cell lines and attenuated expression of ADAM23 was found to be related to hypermethylation in its promoter region. Moreover, the CpG dinucleotide methylation threshold of 70-90% was found to be required for complete silencing. In addition, when some cell lines without ADAM23 expression were treated with 5-aza-2'-deoxycytidine, ADAM23 was reexpressed. In colorectal cancer tissues, the promoter region of ADAM23 was hypermethylated in 36 of 76 (47%). These results demonstrated that ADAM23 may be down-regulated by aberrant promoter hypermethylation during the progression of colorectal cancer.
Choi
Jin-Sung
JS
Laboratory of Cell Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
Kim
Kyung-Hee
KH
Jeon
You-Kyung
YK
Kim
Sung-Hee
SH
Jang
Sang-Geun
SG
Ku
Ja-Lok
JL
Park
Jae-Gahb
JG
D051722:ADAM Proteins / Q000235:genetics*; D001483:Base Sequence; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000235:genetics; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics
D017931:DNA Primers; D004273:DNA, Neoplasm; D051722:ADAM Proteins; C114633:ADAM23 protein, human