Fig. 7

a Representative semi-quantitative RT-PCR demonstrates the gene expression changes for p53, caspase-3, and GAPDH from HCT-15 cells exposed to IC₅₀ concentration of AM-AuNPs with different time points of exposure 24 and 48 h. Lane 1 is control; lanes 2 and 3 are mRNA levels of AM-AuNPs exposed cell samples after 24 h and 48 h of exposure. b Histogram showing densitometry analysis of intrinsic apoptosis-related gene expressions of HCT-15 cells after exposure to AM-AuNPs for 24 and 48 h. Error bars indicate standard deviation of mean for three independent experiments. GAPDH expression was used as loading control. c Representative immunoblot showing expression of apoptosis responsive p53 and caspase-3 proteins and GAPDH as internal loading control from HCT-15 cells exposed to IC₅₀ concentration of AM-AuNPs for 24 and 48 h. d Histogram showing densitometry quantification of apoptotic protein expression. Significant differences assessed by Student’s t test are indicated in **p < 0.001, found to be increased significantly in samples obtained from 24 h and 48 h post exposure periods as compared to unexposed control. Error bars indicate standard deviation of mean for three independent experiments