Inhibitory effects of cyclooxygenase-2 inhibitor and α-interferon on growth of human liver cancer xenografts and tumor angiogenesis in nude mice

Objective To investigate α-interferon (α-IFN) and cyclooxygenase-2 (COX-2)inhibitor celecoxib synergistically inhibit the growth of human liver cancer SMMC-7721 cells xenografts and tumor angiogenesis in a nude mouse model.Methods The effects of celecoxib and α-interferon on tumor volumes and weight were observed.The expressions of VEGF and Cox-2 were determined by immunohistochemistry and RT-PCR,and the effect of α-interferon on MVD also was observed by immunohisto chemistry.Results During the period of observation tumor volume increased progressively in control group,while it was suppressed obviously in other drug treatment groups.The average tumor volume was significantly smaller in celecoxib + α-IFN group than that in IFN group,celecoxib group and control group (P ＜ 0.01,respectively),its inhibitory rate was 61.84％.Immunohistochemistry showes that the VEGF and MVD was significantly smaller in celecoxib + IFN group than that in α-IFN group,celecoxib group and control group (P ＜ 0.01,respectively).RT-PCR shows that the COX-2mRNA and VEGF mRNA pression was lower in the celecoxib + α-IFN group than in α-IFN group,celecoxib group and control group (P ＜ 0.01).Conclusions The COX-2 inhibitor celecoxib and α-interferon synergistically reduces xenografts growth of human liver cancer SMMC-7721 cells effectively via suppressing tumor growth and angiogenesis. Key words: Carcinoma, hepatocellular;  Interferon-α; Cyclooxygenase 2 inhibitors