[Effect of adenomatous polyposis coli(APC) promoter methylation on gene transcription in lung cancer cell lines].
OBJECTIVE
Hypermethylation of CpG islands in adenomatous polyposis coli (APC) gene has been detected in a variety of human tumors, which is involved in the pathogenesis of these tumors. In previous research, we detected APC promoter methylation in 47% lung tumor tissues. This study was to analyze the effect of APC promoter methylation on the gene transcription in 3 lung cancer cell lines.


METHODS
The methylation status of APC promoter 1A in lung adenocarcinoma cell line SPCA1, small cell lung cancer cell line NCI-H446, and big cell lung cancer cell line NCI-H460 was detected by methylation-specific polymerase chain reaction (MSP) and microarray methylated cord blood DNA served as positive control, and unmethylated cord blood DNA served as negative control. The expression of APC was examined by real-time quantitative polymerase chain reaction (PCR) with Sybr-Green I staining. After treatment of 1, 5, 10, 15 micromol/L DNA methyltransferase inhibitor 5-aza-2-deoxycytidine (5-aza-dC), the expression of APC in NCI-H460 cells was detected by real-time PCR.


RESULTS
APC promoter 1A was methylated in NCI-H460 cells, and unmethylated in NCI-H446 and SPC-A1 cells. Hypermethylation was detected in all 5 CpG islands (687, 707, 714, 719, 726) of APC promoter 1A in NCI-H460 cells. The expression of APC in NCI-H460 cells was decreased by 26.04% of that in NCI-H446 cells and by 32.36% of that in SPCA1 cells. After treatment of 1, 5, 10, 15 micromol/L 5-aza-dC, the expression of APC promoter 1A in NCI-H460 cells was enhanced by 4.59, 5.78, 9.58, 5.98 folds, respectively.


CONCLUSIONS
APC gene is hypermethylated in HCI-H460 cells, and its transcription coud be activated by 5-aza-dC.
Zhang
Li-Xia
LX
Center of Clinical Laboratory, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, P. R. China.
Pan
Shi-Yang
SY
Chen
Dan
D
Xie
Er-Fu
EF
Gao
Li
L
Shu
Yong-Qian
YQ
Lu
Zu-Hong
ZH
Cheng
Lu
L
Yang
Di
D
Zhang
Ji-Nan
JN
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics / Q000378:metabolism*; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D018287:Carcinoma, Large Cell / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D000077209:Decitabine; D017491:Genes, APC; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D055752:Small Cell Lung Carcinoma / Q000378:metabolism / Q000473:pathology; D014158:Transcription, Genetic
D025601:Adenomatous Polyposis Coli Protein; D000077209:Decitabine; D001374:Azacitidine