RESUMEN
OBJECTIVE：To investiga te the effects of MEK/ERK pathway specific inhibitor PD 98059 combined with paclitaxel on the proliferation and apoptosis of human gastric signet ring cell carcinoma （SRCC）cells. METHODS ：Using human SRCC KATO Ⅲ cells as object ，CCK-8 assay was used to detect cell proliferation after treated with paclitaxel ，PD98059 and two drug combination for 48 h，and the proliferation rate was calculated. Flow cytometry ，Western blotting and Transwell assay were used to detect the cell proliferation ，the expression of apoptosis related protein （Cleaved-caspase-3）and cell migration after treated with paclitaxel，PD98059 and two drug combination for 48 or 24 h. RESULTS ：After treated with paclitaxel （1 μg/mL），PD98059（5， 20，40 μmol/L）and two drug combination （1 μg/mL+5，20，40 μmol/L），the proliferation rate of cells was increased significantly in administration groups ，and the combination groups were significantly higher than paclitaxel and PD 98059 alone groups （P＜ 0.05）. After treated with paclitaxel （1 μg/mL），PD98059（5，20，40 μmol/L）and two drug combination （1 μg/mL+40 μmol/L）， early and late apoptosis rate ，the protein expression of Cleaved-caspase- 3 were significantly increased in paclitaxel group and combination group ；combination group was significantly higher than paclitaxel and PD 98059 alone group （P＜0.05）. The number of migrated cells in administration groups were reduced significantly ，and the combination group was significantly lower than paclitaxel and PD 98059 alone group （P＜0.05）. CONCLUSIONS ：Paclitaxel and PD 98059 can inhibit the proliferation and migration of human SRCC KATO Ⅲ cells，paclitaxel can also promote the apoptosis and the expression of apoptosis related protein，which may be related to the inhibition of MEK/ERK pathway. The effect of the combination of the two drugs is better than paclitaxel or PD 98059 alone.