Apoptosis of hepatoma cell line HepG2 induced by the combination use of GNRs@SiO2-FA and 125I seeds：an experimental study / 介入放射学杂志

ABSTRACT

Objective To explore the possible mechanism of the apoptosis of hepatoma cell line HepG2 induced by the combination use of GNRs@SiO2-FA and 125I seeds and to discuss its relationship with Bcl-2 and Bax protein expressions so as to provide theoretical basis for clinical treatment of hepatic cancer with interstitial brachytherapy by using 125I seeds. Methods In vitro cultured HepG2 cells were randomly divided into 4 groups blank control group (not treated), simple GNRs@SiO2-FA group, simple 125I seeds group, and combination group (GNRs@SiO2-FA plus 125I seeds). The apoptosis of HepG2 cells was determined by flow cytometry. The expression of Bax mRNA and Bcl-2 mRNA of HepG2 cells were tested by RT-PCR. The apoptosis-related genes (Bax and Bcl-2) and the tumor proliferation cell nuclear antigen (Ki67) proteins expression on HepG2 cells were examined with immunohistochemistry method. Results The flow cytometry examination showed that the apoptosis rate of HepG2 cells in the simple GNRs@SiO2-FA group and simple 125I seeds group was higher than that in blank control group (P<0.05), and the apoptosis rate of the combination group was significantly higher than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group (P< 0.05). The expression level of Bax mRNA in the combination group was higher than that in the simple GNRs@SiO2-FA group and simple 125I seeds group, while the expression level of Bcl-2 mRNA in the combination group was obviously lower than that in the simple GNRs@SiO2-FA group and simple 125I seeds group. Bax protein was expressed on cytoplasm, Bcl-2 protein was expressed on cytoplasm and cell membrane, while Ki67 protein was expressed on nucleus. All of them presented as brown finely granular precipitations. Statistically significant differences in the amount of Bax, Bcl-2 and Ki67 protein expression existed between each other among the four groups (P< 0.05). The positive expression rate of Bax protein in the combination group was significantly higher than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group, while the positive expression rate of Bcl-2 and Ki67 protein was significantly lower than that of the simple GNRs@SiO2-FA group and the simple 125I seeds group, and the differences were statistically significant (P < 0.05). Conclusion The combination use of GNRs@SiO2-FA and 125I seeds can more effectively induce the apoptosis of HepG2 cells. This effect may be accomplished through increasing the expression of Bax protein and inhibiting the expression of Bcl-2 and Ki67 proteins.