Fig. 4

YAP1 in combination with TCF4 and β-catenin regulates MALAT1 expression in colon cancer cells. a YAP1, TCF4, and β-catenin expression levels in HCT116 cells transfected with pEGFP-c1-YAP1, siYAP1, vector or negative control by qRT-PCR. b TCF4 and β-catenin expression levels in HCT116 cells treated with pEGFP-c1-YAP1, siYAP1, vector or negative control by Western blotting. c IP confirmed YAP1 interactions with TCF4 and β-catenin in HCT116 cells (GAPDH, IgG as a negative control). d Promoter activities in HCT116 and SW480 cells co-transfected with luciferase reporters for MALAT1 and silencing plasmids (siYAP1, siTCF4, siβ-catenin or negative control, as indicated) for 48 h. e The expression levels of MALAT1 in HCT116 cells treated with silencing plasmids (siYAP1, siTCF4, siβ-catenin or negative control, as indicated) for 48 h. f The TCF4 motif predicted from JASPAR matrix models. g–j Promoter activities from HCT116 cells co-transfected with luciferase reporters of differently predicted binding-site plasmids (Luc-MAL-pro, Luc-MAL-pro-#1, Luc-MAL-pro-#2, or Luc-MAL-pro-#3) and treated with the silencing plasmids siYAP1, siTCF4, siβ-catenin, or negative control, were measured by dual luciferase reporter assay. Luc-MAL-pro, containing three WT binding sites; Luc-MAL-pro-#1, Luc-MAL-pro-#2, and Luc-MAL-pro-#3, containing the first, second, and third WT binding sites, respectively, away from the transcription start site of MALAT1; E4F1 was assessed as the negative control. k ChIP assays using anti-TCF4, anti-YAP1, and anti-β-catenin antibodies were performed in HCT116 and SW480 cells. A control IgG was used as the negative control for IP. Semi-qPCR was used to assess ChIP signals. BRP binding region primer, URP unrelated region primer. Three independent experiments were performed. *p < 0.05, **p < 0.01, ***p < 0.001 compared to the control group, by Student’s t-test