Study Of Melittin On Tumor Inhibition And Part Of Mechanism Of Human Hepatocellular Carcinoma HepG-2 Xenograft In Nude Mice

Liver cancer is one of the most common malignant tumor in China. It's difficult to be diagnosed and it deteriorate very quickly. Because of recrudescence and metastasis, The prognosis for liver cancer is unsatisfactory. Bee venom is eliminated from sting of spado, which is applied for treatment of rheumatoid arthritis, cancer, skin diseases and other diseases, but there are complicated, toxic side effects. Melittin is the principal toxic component in the venom of the European honey bee Apis mellifera, it is a small linear peptide composed of 26 amino acid residues. HepG-2 liver cancer cell lines is established in vivo. By observing the anti-tumor effect of Milittin and immunological index, discuss the mechanism of Melittin, which provide experimental foundation for development of anti-tumor drug. Mainly includes the following:1. Inhibition of Melittin on hepatocellular carcinoma HepG-2 xenograft in nude mice Melittin could inhibit the growth of tumor in vivo, the inhibitory rates of tumor growth were high. The tumor volume of xenograft in nude mice was significantly smaller in Melittin groups and 5-FU group than that in control group. Histopathological examination revealed the wide spread necrosis with massive accumulation of infiltrating lymphocytes and plasmacytes in the tumors. Heteromorphism of tumors in Melittin group grew down remarkably. 2. Effects of melittin on immunocompetence with tumor-bearing mice Spleen index in mice with tumor increased after Melittin 2,4mg/kg treated, while the level of NO significantly decreased. TNF-αproduction by in tumor bearing mice model were higher than that in control group. Level of IL-1 in the Melittin groups was significantly higher than those in the control group. Melittin could enhance the phagocytic activity of PMΦand the cytotoxicity of NK cell, augment decreased ConA-induced lymphocyte proliferation at doses 2 and 4mg/kg. These results suggest that anti-tumor activity of Melittin may be related to its above effects on immune function.The apoptosis indexes of tumor were measured by TUNEL method. Melittin significantly inhibited the primary tumor cell proliferation and induced tumor cell apoptosis in a dose depedent manner. Anti-tumor activity of Melittin may be related to its effects on reinforcement of the apoptosis of tumor tissue.