Fig. 1. The high expression of KCNN4 in PDAC is regulated by AP-1.

a The heatmap showed the different expression patterns of 24 potassium channel genes in the PDAC tumor tissues (T) and matched normal (MN) tissues based on the clinical sample expression profile data. b KCNN4 was identified to be the most significantly overexpressed potassium channel gene in PDAC. c The level of KCNN4 in clinical PDAC tissue section was detected by immunohistochemical staining. d The level of KCNN4 in normal pancreatic cells HPNE and PDAC cell lines was assessed by Western blotting. e Overexpression KCNN4 was associated with poor survival of PDAC patients analyzed from OncoLnc-linked TCGA database. f Three AP-1 conjectural binding sites in the promoter region of KCNN4 were identified by analysis with JASPAR and PROMO databases. g HEK293T cells were co-transfected with pGL3-KCNN4 reporter plasmid, renilla plasmid, pLVX-zsgreen plasmid or pLVX-JUN plasmid, luciferase activities were detected with a dual-luciferase reporter assay system. h PDAC cell lines were treated with or without AP-1 inhibitor (SP600125, 20 μM) for 6 h or 12 h, the mRNA level of KCNN4 was detected by qPCR. i PDAC cell lines were treated with AP-1 inhibitor (SP600125, 20 μM) for 48 h, the level of KCNN4 was detected by Western blotting. j Knockdown or overexpression of c-Jun in PDAC cells, the levels of c-Jun and KCNN4 were detected by Western blotting. Data are shown as mean ± SEM. **P < 0.01; ***P < 0.001.