Fig. 6

p53 activates PARP1 in AKT inhibition triggered parthanatos. a, b After SC66 treatment for 4 h, mitochondrial, cytoplasmic and nuclear fractions were isolated from HCT116 wild type (a) or HCT116 p53–/– cells (b) and subjected to western blot for detection of the protein levels of PAR, cleaved PARP1, PARP1 and AIF. COX IV, β-actin and H3 was used as the loading control of mitochondria, cytoplasm and nucleus respectively. c Western blotting assay tested the PAR polymer level in different colorectal cancer cells with or without p53 mutation. d Western blotting assay tested the PAR polymer level in HepG2 cells (wild type p53) and DU145 (p53 mutated). e Endogenous co-immunoprecipitation was performed in HCT116 cells. f Exogenous co-immunoprecipitation was performed in p53 null cells transfedted with YFP-p53. g A comparison of PARP1 expression level between CRC tissues and adjacent normal tissues