Fig. 6: p53 downregulated CD51 expression by antagonizing Sp1 and Sp3.

a Luciferase assay for analyzing CD51 promoter activity in LNCaP cells with p53 overexpression or knockdown. LNCaP cells with differentially expressed p53 were transfected with the CD51-promoter–reporter construct and PGL3.0-basic vector for 48 h. The luciferase activity is represented as fold-change. b PC-3 cells were co-transfected with the CD51-promoter–reporter construct, treated with increasing concentrations of p53 and analyzed for luciferase activity after 24 h. c The relationship between CD51 and p53 was detected by immunoblotting. After knocking down p21 and E2F7 and subsequently transfecting the p53 vector into LNCaP cells, the expression of CD51 was detected by immunoblotting. d Immunoblot for CD51 after knocking down Sp1 and Sp3 in LNCaP cells. e EMSA assays showed that the binding of nuclear proteins to the CD51 promoter was detected in both p53-positive and p53-negative cells. In the competition studies, binding complexes could not be detected; the complex of the nuclear protein with the standard oligonucleotide of the Sp1 binding zone was detected at the same level on the gel. The average was calculated based on three independent experiments. Error bars show the mean ± SD from three technical replicates (two-tailed Student’s t-test, ***p < 0.001)