EZH2-mediated epigenetic activation of the CCL22/CCR4 causing EMT process remodeling in cervical carcinoma

Abstract Background: Our previous study revealed the chemokine CCL22 and its receptor CCR4 are elevated in cervical cancer (CC) tissues. The present study aimed to investigate the potential role of EZH2-induced epigenetic activation of CCL22/CCR4 and caused EMT remodeling in CC. Methods: We evaluated whether CCL22-CCR4 expression levels could be regulated by EZH2 and subsequently evaluated the mechanism of EZH2 on the CCL22-CCR4. The animal model supported the experimental findings. Results: CCL22 and CCR4 were significant up-regulated in CC samples compared with normal cervix tissues, and obvious induction of promoter DNA methylation levels of CCL22and CCR4 was shown in CC tissues. Demethylation reactivated the transcription of CCL22 and CCR4. DNMT3A was found to directly bind to the CCL22and CCR4 promoter regions in vitro. Downregulation of the expression of EZH2 in CC cell lines altered DNMT3A expression, induced CCL22and CCR4 promoters’ methylation level as well, and decreased CCL22and CCR4 mRNA expression. An in vivo assay showed that, EZH2 regulated the expression of CCL22/CCR4 components through DNMT3A, consistent with the in vitro results. In EZH2-silenced CC cells, migration was reduced, levels of EMT related markers, including vimentin, slug, snail and β-catenin, were all reduced, and ZO-1 increased. In DNMT3A-silenced CC cells, migration was induced and vimentin, slug, snail and β-catenin were all induced, ZO-1 reduced. Inhibition of CCL22 protein significantly decreased migration of CC cells and vimentin, slug, snail and β-catenin, increased ZO-1. Conclusions: Overall, EZH2 thus appears to regulate CCL22/CCR4 expression via epigenetic activation, causing EMT process remodeling in CC progression.