CHAF1A was upregulated by Sp1 in GC. a Schematic diagram illustrates the Sp1 binding sites on the promoter region of CHAF1A gene. b–c The positive correlation between CHAF1A and Sp1 in the GEO database (GSE63089) (b) and clinical GC samples (c) using Pearson correlation coefficient analysis. d–e The mRNA expression of CHAF1A in AGS and BCG-823 cells transfected with Sp1 siRNA or negative control. f The protein level of the CHAF1A in AGS and BCG-823 cells under the knockdown of the Sp1. g AGS and BGC-823 cells were transfected with Sp1 siRNA, along with wild-type CHAF1A promoter reporter plasmid or mutant CHAF1A promoter reporter plasmid for 24 h, and then luciferase assay was performed. h The promoter activity of CHAF1A was also performed in BGC-823 cells transfected with Sp1 expression plasmids. i ChIP analysis of Sp1 binds to CHAF1A gene promoter region. Similar results were acquired in three independent experiments. Every bar represents the mean ± s.e.m. of three independent experiments in (d), (e), (g), (h) and (i). **p < 0.01, ***p < 0.001 by Student's t-test.