DNA hypermethylation and decreased mRNA expression of MAL, PRIMA1, PTGDR and SFRP1 in colorectal adenoma and cancer

BMC Cancer

Research Article

Ilona Kovalszky¹  Vivien Kubák¹  Péter Hollósi²  Árpád V. Patai³  Kinga Tóth³  Zsófia Brigitta Nagy³  Alexandra Kalmár⁴  Bálint Péterfia⁴  Béla Molnár⁴  Zsolt Tulassay⁴  András Bodor⁵  Gábor Valcz⁶  Orsolya Galamb⁶  Barnabás Wichmann⁶  Sándor Spisák⁶ 

[1] 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary;1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary;Tumour Progression Research Group, Hungarian Academy of Sciences, Budapest, Hungary;2nd Department of Internal Medicine, Semmelweis University, Budapest, Hungary;2nd Department of Internal Medicine, Semmelweis University, Budapest, Hungary;Molecular Medicine Research Group, Hungarian Academy of Sciences, Budapest, Hungary;Department of Physics of Complex Systems, Eötvös Loránd University, Budapest, Hungary;Molecular Medicine Research Group, Hungarian Academy of Sciences, Budapest, Hungary;

关键词: DNA methylation;    Colorectal cancer;    Gene expression;    Pyrosequencing;    Laser capture microdissection;   

DOI  :  10.1186/s12885-015-1687-x

 received in 2014-10-13, accepted in 2015-10-07,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundColorectal cancer (CRC) development is accompanied by changes in expression for several genes; but the details of the underlying regulatory procesess remain unknown. Our aims were to assess the role of epigenetic processes in tumour formation and to identify characteristic DNA methylation and miRNA alterations in the colorectal adenoma-carcinoma sequence.MethodsWhole genome expression profiling was performed on colonic biopsy samples (49 healthy normal, 49 colorectal adenoma (AD), 49 CRC); on laser capture microdissected (LCM) epithelial and stromal cells from 6 CRC-normal adjacent tissue (NAT) samples pairs, and on demethylated human CRC cell lines using HGU133 Plus 2.0 microarrays (Affymetrix). Methylation status of genes with gradually altering expression along the AD-CRC sequence was further analysed on 10–10 macrodissected and 5–5 LCM samples from healthy colon, from adenoma and from CRC biopsy samples using bisulfite-sequencing PCR (BS-PCR) followed by pyrosequencing. In silico miRNA prediction for the selected genes was performed with miRWALK algorithm, miRNA expression was analysed on 3 CRC-NAT sample pairs and 3 adenoma tissue samples using the Human Panel I + II (Exiqon). SFRP1 immunohistochemistry experiments were performed.ResultsA set of transcripts (18 genes including MAL, SFRP1, SULT1A1, PRIMA1, PTGDR) showed decreasing expression (p < 0.01) in the biopsy samples along the adenoma-carcinoma sequence. Three of those (COL1A2, SFRP2, SOCS3) showed hypermethylation and THBS2 showed hypomethylation both in AD and in CRC samples compared to NAT, while BCL2, PRIMA1 and PTGDR showed hypermethylation only in the CRC group. miR-21 was found to be significantly (p < 0.01) upregulated in adenoma and tumour samples compared to the healthy colonic tissue controls and could explain the altered expression of genes for which DNA methylation changes do not appear to play role (e.g. BCL2, MAL, PTGS2). Demethylation treatment could upregulate gene expression of genes that were found to be hypermethylated in human CRC tissue samples. Decreasing protein levels of SFRP1 was also observed along the adenoma-carcinoma sequence.ConclusionHypermethylation of the selected markers (MAL, PRIMA1, PTGDR and SFRP1) can result in reduced gene expression and may contribute to the formation of colorectal cancer.

【 授权许可】

CC BY   
© Kalmár et al. 2015