Epigenetic network of EZH2/SFRP1/Wnt in the epithelial-mesenchymal transition of laryngeal carcinoma cells

Wei Chen, Hua-Tao Wang, Jun-Feng Ji, Zhi-Yi Wang, Tao Shi, Ming-Hai Wu,  Peng-Ju Yu

Abstract:

Enhancer of Zeste Homologue 2 (EZH2) as a histone methyltransferase epigenetically regulates laryngeal carcinoma (LGC) progression. The present study sought to explore the role and mechanism of EZH2 in the epithelial-mesenchymal transition (EMT) of LGC cells. Expressions of EZH2, secreted frizzled-related protein 1 (SFRP1), and trimethylation of lysine 27 on histone H3 (H3K27me3) in LGC tissues or cells were detected via reverse transcription quantitative polymerase chain reaction (qRT-PCR) and western blotting. Upon transfection of si-EZH2, si-SFRP1, oe-SFRP1, or H3K27me3 upregulation, cell viability was assessed via cell counting kit-8, protein levels of E-cadherin, N-cadherin, β-catenin, c-Myc, and Cyclin D1 were determined via western blotting, and Vimentin expression was determined via immunofluorescence. The enrichment level of H3K27me3 in the SFRP1 promoter was measured via chromatin immunoprecipitation-PCR. EZH2 was highly expressed in LGC tissues and cells. Silencing EZH2 repelled the EMT of LGC cells. Mechanically, EZH2 upregulated H3K27me3 in the SFRP1 promotor to inhibit SFRP1 expression, and SFRP1 overexpression inactivated the Wnt pathway. H3K27me3 upregulation or SFRP1 downregulation reversed the inhibition of silencing EZH2 in the EMT of LGC cells. Overall, EZH2 upregulated H3K27me3 in the SFRP1 promoter to inhibit SFRP1 expression and activate the Wnt pathway, thereby facilitating the EMT of LGC cells.