Effect Of Tyroserleutide On PI3K Signaling Pathway In Human Hepatocarcinoma Cells

Objective:To investigate the possible mechanism of polypeptides tyroserleutide affecting on PI3K signaling in human hepatocarcinoma BEL-7402 tumor cells. Methods:1. The animal model of human hepatocarcinoma BEL-7402 xenografts in nude mice is used to investigate the anti-cancer effect of tyroserleutide. Two dosages, 320μg/kg/d and 160μg/kg/d, were used to observe the effect.2. Purified PI3K antigen from hepatocarcinoma cells by immunoprecipitation. PI3-Kinse ELISA kit was used to assay the difference of PI3K activity between tyroserleutide group and saline group.3. In order to investigate he inhibitory effect, Western Blot was used to observe the effect of tyroserleutide on PI3K regulatory subunits P85 protein expression, and Real-time Q PCR was used to measure P85a mRNA expression in hepatocarcinoma cells.4. Real-time Q PCR was used to observe the effect of tyroserleutide 320μg/kg/d group on PI3K caralytic subunits P110α, P110γ mRNA expression in hepatocarcinoma cells.Results:1. Tyroserleutide could remarkably inhibit the growth of human hepatocarcinoma BEL-7402 xenografts in nude mice. A significant 38.09% and 28.46% inhibitory index were observed in 320μg/kg/d and 160μg/kg/d dosage group respectively ( p<0.05).2. Tyroserleutide 320μg/kg/d and 160μg/kg/d dosage group could significantly lower the PI3K activity compared with saline group ( p<0.05).3. Tyroserleutide 320ng/kg/d group could decrease the protein expression of tumor PI3K regulatory subunits P85. In order to further investigate the mechanism of tyroserleutide effect, we used real-time Q PCR method, results showed that tyroserleutide could lower the mRNA expression of P85a than saline group.4. Tyroserleutide 320ug/kg/d group could significantly lower mRNA expression of P11 Oa and P11 Oy than saline group.Conclusion:Tyroserleutide could significantly inhibit the growth of human hepatocarcinoma BEL-7402 xenografts in nude mice. The anti-cancer effect might be result from the YSL inhibiting mRNA and protein expression of PI3K regulatory subunits P85, P85a, and catalystic subunits PllOa, PllOy. Abnormal PI3K activity was inhibited, and then according abnormal cell signaling pathway was inhibited.