Expressed CpG island sequence tag microarray for dual screening of DNA hypermethylation and gene silencing in cancer cells.
We present a novel concept by using expressed CpG island sequence tags (ECISTs)for dual analysis of DNA methylation and gene expression in cancer cells. ECISTs are present in the genome and are DNA fragments expected to be located in the promoter and first exon region of genes. Their GC-rich segments can be used for screening hypermethylated CpG sites in cancer cells, and their exon-containing portions can be used for measuring levels of the corresponding transcripts. A total of 1162 loci met the criteria of ECISTs from an initial screening of 7776 CpG island tags. This ECIST panel was used to analyze the breast cancer cell line MDA-MB-231, which was treated with a demethylating agent. Microarray profile analysis identified 30 methylation-silenced genes, the expression of which could be directly reactivated by demethylation. An additional group of 96 up-regulated genes was also identified but appeared to be downstream from this epigenetic cascade. Thus, this study shows that the ECIST microarray can be used to differentiate the primary and secondary causes of demethylation and provides an effective tool to elucidate the mechanisms of aberrant DNA methylation in cancer.
Shi
Huidong
H
Department of Pathology and Anatomical Sciences, Ellis Fischel Cancer Center, University of Missouri School of Medicine, 115 Business Loop I-70 West, Columbia, MO 65203, USA.
Yan
Pearlly S
PS
Chen
Chuan-Mu
CM
Rahmatpanah
Farahnaz
F
Lofton-Day
Catherine
C
Caldwell
Charles W
CW
Huang
Tim Hui-Ming
TH
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D018899:CpG Islands; D019175:DNA Methylation; D020224:Expressed Sequence Tags; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D014407:Tumor Cells, Cultured
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase