Rapamycin inhibited the growth of hepatocellular carcinoma in nude mice

Objective To study the antitumor effort of rapamycin on hepatocellular carcinoma and the relevant mechanism. Methods Nude mice bearing orthotopic xenografty human HCC were randomly divided into 4 groups: control group, tacrolimus group, rapamycin group, rapamycin high dose group. The effect on the tumor growth was evaluated using tumor volume after 2 weeks. PCNA and VEGF expression in liver cancer tissue was detected by using immunohistochemistry. Results The tumor volume was (310.15 ± 40.16), (605.59±116.23), (99.19±15.27), (151.61±27.81) mm3 in control, tacrolimus, rapamycin and rapamycin high dose groups respectively. The tumor volume was significantly decreased in rapamycin group and rapamycin high dose group, but increased in tacrolimus group as compare with control group. The expression of PCNA and VEGF was downregulated in rapamycin group and rapamycin high dose group as compare with control group. Conclusion The growth of HCC in the nude mice was inhibited when the animals were exposed to rapamycin but enhanced when exposed to tacrolimus. The antitumor effort of rapamycin attributes to the retardation of tumor cell growth and the downregulation of VEGF expression probably.