Inhibitory effect of arsenic trioxide on tumor growth and angiogenesis in nude mice bearing transplanted tumor
AIM: To investigate the inhibitory effect of As2O3 on gastric tumor growth and angiogenesis and on the expression of Flt-1. METHODS: Solid tumor models were established in 30 nude mice with gastric cancer cell line SGC-7901. The mice were divided randomly into two treatment groups (5 mg/kg As2O3 and 2.5 mg/kg As2O3) and control group, with 10 in each group. As2O3 was injected to the arsenic-treatment groups (2. 5 mg/kg and 5 mg/kg) and the same volume of saline solution was injected to the control group. Tumor growth inhibition (TGI) was used to assess the inhibitory efficacy of As2O3 against xenografts. Mi-crovessel density (MVD) and Flt-1 were detected by immunofluo-rescence laser confocal microscopy. RESULTS: In 5 mg As2O3 and 2.5 mg As2 O3 treatment groups, the tumor growth inhibition rates were 29.08% and 52.17% respectively. Decrease of MVD was observed in As2O3 treatment tumors compared with that in control group(P<0.01). MVD in tumors was significantly lower in 5mg group than that in 2.5 mg group( P <0.01). The expression of Flt-1 was less in As2O3 treatment mice compared with that in controls, and less in 5mg As2O3 treatment group compared with that in 2. 5mg As2O3 treatment group ( P < 0. 01 ). CONCLUSION: As2O3 inhibits solid tumor growth and decreases MVD in tumors, possibly by inhibiting the expression of Flt-1.