Fig. 6. TP63 suppresses ISGs by inhibiting STAT1.

A Integrative genomic viewer (IGV) tracks of ChIP-seq revealing binding peaks for STAT1 and TP63 on the promoter or enhancer loci of indicated IFN response genes. The occupancy of TP63 at the SOX2 locus is shown as a positive control. ChIP-seq data were retrieved from GSE78212, GSE46837, GSE106563, and GSE148920. Gray shadows highlighting promoter region of each gene. B TP63-interactome analysis by cross-referencing immunoprecipitation-mass spectrometry (IP-MS). Blue, green, and red dots indicate respectively solo-, duo- or trio-interacted proteins with TP63, KLF5, or SOX2. The 12 common proteins showing interaction with TP63, KLF5, and SOX2 in both datasets were listed. Data in red dotted-line rectangle were from our previous publication²⁸; SOX2-MS data was retrieved from Watanabe et al. ²⁶. C Co-IP followed by Western blotting analysis showing the protein interaction between TP63 and phosphorylated STAT1 (Ser727 and Tyr701) in both human TT and murine MOC22 cells. D Representative IF staining displaying the localization of TP63 and p-STAT1 (Ser727) in MOC22 cells stimulated with IFNγ (100 ng/mL). Zoom-in view as shown on the right. The similar results were repeated in three biologically independent experiments. E, F qRT-PCR (E) and Western blotting (F) analysis revealing relative mRNA and protein levels of STAT1, TP63 and p-STAT1 in both TT and MOC22 cells expressing Scramble or shTP63/shTrp63 ± IFNγ (100 ng/mL) for 48 h. P value for the comparison from left to right in E: 0.0081, 0.0099, 0.0061, 0.0049, 0.0064, 0.0314, 0.0056, and 0.0463. G Western blotting analysis showing levels of indicated proteins. SCC cells (KYSE410 and TE1) with low expression of TP63 were transfected with TP63 over-expression (OE) or empty vector (Control) following 24 and 48 hr stimulation of IFNγ (100 ng/mL). The results were repeated with three biologically independent experiments in two cell lines. H, I qRT-PCR (H) and Western blotting (I) analysis revealing a time-dependent expression of STAT1, TP63, and p-STAT1 in TT cells in responding to the stimulation of IFNγ (100 ng/mL). P value for the comparison from left to right in H: 0.0017, 0.0020, 0.0021, 0.0013 for STAT1 expression; 0.0191, 0.0004, 0.0002, 5.08E-05 for TP63 expression. J Western blotting showing expression of STAT1, TP63, and p-STAT1 in both TT and TE5 cells treated with IFNγ (100 ng/mL) or/and Fludarabine, a STAT1-specific inhibitor. The results of panels (E–H, J) were repeated with three biologically independent experiments in two cell lines. The results of panels (C, I) were repeated in four biologically independent cell lines. E, H Data represent mean ± SD of three biologically independent experiments. P values were determined using a two-sided t test. *P < 0.05, **P < 0.01, ***P < 0.001. Source data are provided as a Source Data file.