Apoptosis Of HepG₂ Cell Line Induced By The Combinationof Folic Acid-conjugated Silica-coated Gold Nanorods And Iodine 125 Seeds

Objective The cancer of the liver was relatively insensitive to radiation.So how to improve the radiosensitivity and therapeutic gain factor was difficulty of the radiotherapy of liver cancer.To explore the apoptosis of hepatoma cell line Hep G2 induced by the treatment of GNRs@Si O2-FA combined with Iodine 125 seeds and its relationship with Bcl-2 and Bax protein expressions.Methods Cultured Hepatocellular carcinoma cells in vitro,at the same time preparation of gold nanorods(GNRs) by seed growing method, and then using the silica as the shell material,synthesis of silica coated gold nanorods(GNRs@Si O2), finally the folate were coupled to the silica coated gold nanorods to prepared nano probe folate-conjugated(GNRs@Si O2-FA). Characterization of targeting probe and observation the process of GNRs@Si O2-FA into the cells by using transmission electron microscopy(TEM). MTT colorimetric method was used to assess the biocompatibility of GNRs@Si O2-FA. In vitro cultured Hep G2 cells were divided into 4 groups:control group(not treated),GNRs@Si O2-FA group,Iodine 125 seeds group,and combination group.The apoptosis of Hep G2 cells were determined by flow cytometry. Expression of Bax m RNAand Bcl-2 m RNA of Hep G2 cells were investigated by RT-PCR. Bax,Bcl-2,Caspase-3 and Ki67 proteins expression on Hep G2 cells were examined with western blotting and immunohistochemistry.Results A cancer cell targeting probe based on silica-coated gold nanorods were developed. GNRs@Si O2-FA <40 μg/m L concentration range was safe for biological activity of Hep G2 cells. The apoptosis rates of Hep G2 cells were higher in GNRs@Si O2-FA group,Iodine 125 seeds group than in control group(P<0.05). It was also significantly higher in combination group than in GNRs@Si O2-FA group and Iodine 125 seeds group(P<0.05).The expression of Bax m RNA significantly increased and the expression of Bcl-2 m RNA significantly decreased in combination group than in GNRs@Si O2-FA group and Iodine 125 seeds group. Western blotting analysis showed the apoptosis-related protein of Bax and Caspase-3 were significantly up-regulated, the expression of Bcl-2 was down-regulated.Bax protein was expressed on cytoplasm, Bcl-2 protein was expressed on cytoplasm and cell membrane, Ki67 protein was express on nucleus, and both were asystematic and buffy. The expressions of Bax and Bcl-2 were also significantly different among these four groups(P<0.05).Compared with GNRs@Si O2-FA group and Iodine 125 seeds group, Bax protein prominent increased in combination group,but Bcl-2 and ki67 proteins were much lower(P<0.05).Conclusion The combination of GNRs@Si O2-FA and Iodine 125 seeds more effectively induce the apoptosis of Hep G2 cells. It may be achieved by increasing the expression of Bax protein and inhibiting the expression of Bcl-2,Ki67 proteins.It is a new approach in the treatment of primary liver cancer.