These authors contributed equally.
Global alterations of DNA methylation in cholangiocarcinoma target the Wnt signaling pathway
Article first published online: 24 DEC 2013
© 2013 by the American Association for the Study of Liver Diseases
Volume 59, Issue 2, pages 544–554, February 2014
How to Cite
Goeppert, B., Konermann, C., Schmidt, C. R., Bogatyrova, O., Geiselhart, L., Ernst, C., Gu, L., Becker, N., Zucknick, M., Mehrabi, A., Hafezi, M., Klauschen, F., Stenzinger, A., Warth, A., Breuhahn, K., Renner, M., Weichert, W., Schirmacher, P., Plass, C. and Weichenhan, D. (2014), Global alterations of DNA methylation in cholangiocarcinoma target the Wnt signaling pathway. Hepatology, 59: 544–554. doi: 10.1002/hep.26721
Potential conflict of interest: Nothing to report.
Supported by grants from the Deutsche Forschungsgemeinschaft (DFG) to P.S. and K.B. (SFB/TRR77; Liver Cancer – From Molecular Pathogenesis to Targeted Therapies) and from the Helmholtz Foundation to C.P. The work was supported by the Biobank of the National Center of Tumor Diseases (NCT) Heidelberg.
- Issue published online: 29 JAN 2014
- Article first published online: 24 DEC 2013
- Accepted manuscript online: 3 SEP 2013 12:11PM EST
- Manuscript Accepted: 23 AUG 2013
- Manuscript Revised: 8 JUL 2013
- Manuscript Received: 10 APR 2013
The molecular mechanisms underlying the genesis of cholangiocarcinomas (CCs) are poorly understood. Epigenetic changes such as aberrant hypermethylation and subsequent atypical gene expression are characteristic features of most human cancers. In CC, data regarding global methylation changes are lacking so far. We performed a genome-wide analysis for aberrant promoter methylation in human CCs. We profiled 10 intrahepatic and 8 extrahepatic CCs in comparison to non-neoplastic biliary tissue specimens, using methyl-CpG immunoprecipitation (MCIp) combined with whole-genome CpG island arrays. DNA methylation was confirmed by quantitative mass spectrometric analysis and functional relevance of promoter hypermethylation was shown in demethylation experiments of two CC cell lines using 5-aza-2′deoxycytidine (DAC) treatment. Immunohistochemical staining of tissue microarrays (TMAs) from 223 biliary tract cancers (BTCs) was used to analyze candidate gene expression at the protein level. Differentially methylated, promoter-associated regions were nonrandomly distributed and enriched for genes involved in cancer-related pathways including Wnt, transforming growth factor beta (TGF-β), and PI3K signaling pathways. In CC cell lines, silencing of genes involved in Wnt signaling, such as SOX17, WNT3A, DKK2, SFRP1, SFRP2, and SFRP4 was reversed after DAC administration. Candidate protein SFRP2 was substantially down-regulated in neoplastic tissues of all BTC subtypes as compared to normal tissues. A significant inverse correlation of SFRP2 protein expression and pT status was found in BTC patients. Conclusion: We provide a comprehensive analysis to define the genome-wide methylation landscape of human CC. Several candidate genes of cancer-relevant signaling pathways were identified, and closer analysis of selected Wnt pathway genes confirmed the relevance of this pathway in CC. The presented global methylation data are the basis for future studies on epigenetic changes in cholangiocarcinogenesis. (Hepatology 2014;59:544–554)