The downregulation of KCNN4 prevented the EMT while promoting apoptosis in PTC cell lines. (A, B) Single GSEA based on data from TCGA demonstrated that KCNN4 was associated with the EMT and apoptosis. (C) Silencing KCNN4 promoted apoptosis in PTC cell lines. (D, E) Silencing KCNN4 upregulated E-cadherin and downregulated N-cadherin, Vimentin and Slug at the mRNA and protein levels. (F) qRT-PCR demonstrated that downregulating KCNN4 enhanced Bax expression but reduced Bcl-2 expression. (G) Western blotting assays revealed that downregulating KCNN4 increased Bax expression and reduced Bcl-2 and Bcl-xl expression at the protein level. *p<0.05 and **p<0.01 in comparison with the Si-NC group using Student’s t-test.