Abstract
Aberrant DNA methylation within the promoter regions is associated with the tumorigenesis, yet no whole epigenomic targeting method has been developed to target all of the aberrant loci. We then aimed to establish a global epigenomic targeting method to efficiently against specific cancer cells. To identify and target all the methylation differences between the estrogen receptor (ER) expressing (MCF7, ER+) versus the nonexpressing (MDA-MB-231, ER−) breast cancer cells, a methylation subtraction method was established. Identified targets was validated by high-throughput sequencing and quantitative PCR, and the efficiency of targeting was validated by the cell death phenotype, increased DNA methylation and reduced expression in the target genes. Targeted methylation within these identified loci specifically killed the MDA-MB-231 cells but not the MCF7 cells either in culture or the tumors grown in immuno-deficient mice. To narrow down the number of targets, we identified and targeted 19 of the estrogen receptor-governed loci that were hypomethylated in the MDA-MB-231, implicating their role in the survival and malignance of these ER− cells. The targeted methylation was sufficient to kill the ER− cells in culture. Among these 19 loci, targeted ENSA methylation alone was sufficient to kill the MDA-MB-231 cell specifically in culture as well as in immuno-deficient mice. Overall, a global targeted methylation methodology was established that could be used to identify and target the methylation differences between two cells. These results indicated that the developed global knock-down method might serve as a whole genome validation and therapeutic alternatives. (Supported in part by NSC 97-2320-B-194-003-MY3, NSC 98-3112-B-194-001 and NSC 97-2627-B-006-003)
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 183.
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