Expression of MUC5AC, an early marker of pancreatobiliary cancer, is regulated by DNA methylation in the distal promoter region in cancer cells.
OBJECTIVE
High de novo expression of MUC5AC (a gastric-type secreted mucin) is observed in many types of pancreatobiliary neoplasms, including precursor lesions. In this study, we show that the DNA methylation pattern is intimately correlated with MUC5AC expression in ten cancer cell lines (breast, lung, pancreas, and colon).


METHODS
The CpG methylation status of the MUC5AC promoter from -3855 to +321 was mapped using MassARRAY analysis, which utilizes base-specific cleavage of nucleic acids. ChIP assays and micro-RNA (miRNA) microarray expression profiling were also carried out in both MUC5AC-positive cells and in those with no or low MUC5AC expression.


RESULTS
In the distal region from -3718 to -3670 of the promoter, MUC5AC-negative cancer cells (e.g., MDA-MB-453) were highly methylated, whereas MUC5AC-positive cells (e.g., MCF-7) had low methylation levels. The modification status of histone H3 lysine 9 (H3-K9) was also closely related to MUC5AC expression. Expression levels of miRNAs in the cancer cells were not correlated with MUC5AC expression.


CONCLUSIONS
Our results indicate that MUC5AC is regulated by CpG methylation and histone H3-K9 modification of the MUC5AC promoter distal region, but not by miRNAs. An understanding of the epigenetic regulation of MUC5AC may be of importance for the diagnosis of carcinogenic risk in the pancreatobiliary system.
Yamada
Norishige
N
Department of Human Pathology, Field of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan. yamada54@m.kufm.kagoshima-u.ac.jp
Nishida
Yukari
Y
Yokoyama
Seiya
S
Tsutsumida
Hideaki
H
Houjou
Izumi
I
Kitamoto
Sho
S
Goto
Masamichi
M
Higashi
Michiyo
M
Yonezawa
Suguru
S
D001661:Biliary Tract Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D055271:Mucin 5AC / Q000096:biosynthesis / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic; D012334:RNA, Neoplasm / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
C524678:MUC5AC protein, human; D055271:Mucin 5AC; D012334:RNA, Neoplasm