Inhibition effect of Endostar on angiogenesis partly through VEGF165b,the Inhibitory splice variant of VEGFA

OBJECTIVE:To investigate the impact of endostar on the expression of VEGF165b,and determine the effect of VEGF165b for he sensitivity of tumor cell to endostar. METHODS:The expression of VEGF165b of SMMC-7721 was detective by RT-PCR and Western Blotting after treated with endostar. After transfected with VEGF165b,the expression of HIF-1α and its downstream target genes VEGFA was analyzed by RT-PCR and Immunofluorescent confocal microscopy. SMMC-7721 cell was transfected with VEGF165b or empty vector,and then treated with endostar,the cell growth inhibiting rate was detected by methly thiazolyl tetrazolium (MTT). RESULTS:High dose endostar at 100 and 400 μg/mL up-regulated the expression of VEGF165b,while VEGF165b suppressed the expression of HIF-1α and its downstream target genes VEGFA. After transfection with empty-vector,treatment of SMMC-7721 cell with 500 and 1 000 μg/mL endostar induced the tumour cell growth inhibiting rate at 1.6% and 0.4% individually. After transfection with VEGF165b,treatment of SMMC-7721 cell with 500 and 1 000 μg/mL endostar induced the tumour cell growth inhibiting rate at 8.5% (P=0.000 0) and 20.2%( P=0.000 0) individually. CONCLUSIONS:Endostar can inhibite tumour growth and anti-angiogenisis partly via VEGF165b,and VEGF165b sensitize the tumour cell to endostar. VEGF165b and endostar have synergistic effect on tumor suppression.