Abstract 1365: Epigenetic modification of LY6K in CGI shore and CGI regulates LY6K gene activation and metastatic function in breast cancer

Abstract

Lymphocyte antigen 6 complex locus K (LY6K) is associated with development of the immune response and carcinogenesis. Elevated LY6K by AP-1 activation induces cell invasion and metastasis through activating the Raf-1/MEK/ERK signaling pathway. However, the exact epigenetic mechanism of LY6K gene expression has yet to be clarified. To elucidate the epigenetic mechanism of LY6K gene regulation and expression, CpG island and 5′CGI shore in the region around transcription start site of the LY6K were predicted using UCSC genome browser and Methprimer software. We performed MSP, bisulfite pyro-sequnecing, and bisulfite sequencing to investigate the DNA methylation status of CpG sites from -400 to +500 on the LY6K CGI and 5′CGI shore. Breast cancer cells with low LY6K expression were highly methylated in the both CGI and 5′CGI shore region, whereas high LY6K expression cell lines had low methylation levels. Moreover, 5-Aza-dC, demethylaing agent, treatment of cells with low LY6K expression caused elevation of LY6K expression and finally leads wound healing. To further validate the inverse correlation between LY6K 5′CGI shore methylation and LY6K expression in vivo seen in breast cancer cell lines, we performed bisulfite pyro-sequencing and tissue microarray using breast carcinoma samples. LY6K expression inversely correlates with methylation status and histone modification of 5′CGI shore in the LY6K promoter in human breast cancers. An understanding of epigenetic changes in LY6K may contribute to the diagnosis of carcinogenic risk and to prediction of outcome in patients with breast cancer. Citation Format: Hyun Kyung Kong, Sae Jeong Park, Ye Sol Kim, Jong Hoon Park. Epigenetic modification of LY6K in CGI shore and CGI regulates LY6K gene activation and metastatic function in breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1365. doi:10.1158/1538-7445.AM2014-1365