Mechanism of hydroxyapatite nanoparticles inducing apoptosis of human hepatoma cell line BEL7402

Abstract

Objective To investigate the mechanism of apoptosis induction bu nano hydroxyapatite nano-particles (HAP).Methods Western blotting was used to detect the expression of anti-oncogene p53 and that of oncogene c-myc.The catalytic activity of the Caspases was measured by using a colofimetric assay.Telomeric repeat amplification protocol (TRAP) combined with enzyme-linked immunosorbent assay (ELISA) was used to detect the inhibitory rate of telomerase activity.Results The treatment of BEL-7402cells with nano-HAP decreased the expression of p53 protein,but increased the expression of c-myc protein.The Caspase-3 activity was increased during nano-HAP-induced apoptosis,while the telomerase activity was decreased by nano-HAP in a dose- and time-dependent manner.With the progressive increases in concentrations of nano-HAP (0,50,75,100,150,200 mg/L),the telomerase activity was down-regulated ( 1.94,1.26,1.21,1.14,0.86,0.59,respectively,all P ＜ 0.O1 ).At the concentration of 50 mg/L nano-HAP at different time points (0,12,24,36,48 h),the telomerase activity was down-regulated ( 1.94,1.73,1.57,1.43,1.26,respectively,all P ＜0.O1 ).Conclusion These results suggested that nano-HAP-induced apoptosis was mediated by altering the expression of anti-oncogene p53 and oncogene cmyc,activating Caspase-3 and inhibiting activity of telomerase. Key words: Hydroxyapatite nanoparticles; Carcinoma, hepatocellular; p53; Caspase-3; Telomerase