Fig. 5: HNF1A acts as a transcription factor that binds directly to the SHH promoter region.

a The dual-luciferase reporter assay was used to detect the luciferase activity of different groups after transfection for 48 h. b Venn diagram showing five shared genes among the three indicated groups. c RT‒qPCR was performed to detect the expression levels of HNF1A and SHH mRNA in different groups. d Kaplan–Meier curves showing the OS, PFS, and PPS among LUAD patients in the TCGA database stratified by HNF1A expression. e, f Detection of SHH-pGL3 promoter luciferase activity in HNF1A-knockdown A549/PR cells and HNF1A-overexpressing A549 cells. g Luciferase activity was measured at 48 h post transfection and 24 h after triptolide treatment. h The schematic diagram showed the promoter region of SHH (−499 to +101 bp), and motif analysis of the HNF1A binding element was performed. Mutant (Mut) promoter sequences were designed for insertion into the luciferase vector (pGL3-Basic) based on the predicted binding site sequence. i Detection of mutant promoter activity in HNF1A-overexpressing A549 cells using dual-luciferase reporter assays. j ChIP assays were performed using a specific HNF1A or IgG antibody. The results were semi-quantified by agarose gel electrophoresis. k Quantitative analysis of ChIP results using real-time qPCR. Data are presented as the mean ± SD, *P < 0.05, **P < 0.01, ***P < 0.001. TPL triptolide, OS overall survival, PFS progression-free survival, PPS post-progression survival.