Manipulation of prostate cancer metastasis by locus-specific modification of the CRMP4 promoter region using chimeric TALE DNA methyltransferase and demethylase

Abstract

// Ke Li 1, * , Jun Pang 1, * , Huaiyan Cheng 2, * , Wei-Peng Liu 3 , Jin-Ming Di 1 , Heng-Jun Xiao 1 , Yun Luo 1 , Hao Zhang 1 , Wen-Tao Huang 1 , Ming-Kun Chen 1 , Liao-Yuan Li 1 , Chun-Kui Shao 4 , Ying-Hong Feng 2 , Xin Gao 1 1 Department of Urology, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China 2 Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda MD20814, USA 3 Department of Urology, the First Affiliated Hospital of Nan Chang University, Nanchang 330006, China 4 Department of Pathology, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China * These authors have contributed equally to this work Correspondence to: Xin Gao, e-mail: gaoxin44@vip.163.com Ying-Hong Feng, e-mail: ying.feng@usuhs.edu Keywords: prostate cancer, metastasis, transcription activator-like effectors (TALEs), CRMP4, epigenetic manipulation Received: December 15, 2014      Accepted: January 25, 2015      Published: April 09, 2015 ABSTRACT Prostate cancer is the most commonly diagnosed non-cutaneous cancer and one of the leading causes of cancer death for North American men. Whereas localized prostate cancer can be cured, there is currently no cure for metastatic prostate cancer. Here we report a novel approach that utilizes designed chimeric transcription activator-like effectors (dTALEs) to control prostate cancer metastasis. Transfection of dTALEs of DNA methyltransferase or demethylase induced artificial, yet active locus-specific CpG and subsequent histone modifications. These manipulations markedly altered expression of endogenous CRMP4, a metastasis suppressor gene. Remarkably, locus-specific CpG demethylation of the CRMP4 promoter in metastatic PC3 cells abolished metastasis, whereas locus-specific CpG methylation of the promoter in non-metastatic 22Rv1 cells induced metastasis. CRMP4-mediated metastasis suppression was found to require activation of Akt/Rac1 signaling and down-regulation of MMP-9 expression. This proof-of-concept study with dTALEs for locus-specific epigenomic manipulation validates the selected CpG methylation of CRMP4 gene as an independent biomarker for diagnosis and prognosis of prostate cancer metastasis and opens up a novel avenue for mechanistic research on cancer biology.