目的 探讨卡培他滨联合阿司匹林对SGC-7901细胞增殖和凋亡的体外抑制作用及其作用机制。方法 体外培养SGC-7901细胞，MTT法检测卡培他滨1.0 μmol/L与阿司匹林0.5、1.0、3.0 mmol/L单用和联用对SGC-7901细胞体外增殖的抑制作用；倒置相差显微镜观察卡培他滨1.0 μmol/L与阿司匹林3.0 mmol/L单独及联合用药对SGC-7901细胞形态的影响；PI/Annexin V-FITC双染色流式细胞术分析卡培他滨1.0 μmol/L与阿司匹林3.0 mmol/L单独及联合用药诱导SGC-7901的细胞凋亡率；Western blotting分析卡培他滨1.0 mmol/L与阿司匹林3.0 mmol/L单独及联合用药对COX-2、VEGF表达的影响。结果 卡培他滨与阿司匹林对SGC-7901细胞均有生长抑制作用，且联合组的抑制率高于卡培他滨组和阿司匹林组，两组间比较差异具有统计学意义（P<0.05）。用药处理24 h后，在显微镜下可观察到SGC-7901细胞发生细胞凋亡的形态学改变，联合组相对于卡培他滨、阿司匹林单独用药组的变化更明显。PI/Annexin V双染分析表明，卡培他滨1.0 μmol/L＋阿司匹林3.0 mmol/L联合组的细胞凋亡率明显高于阿司匹林3.0 mmol/L组或卡培他滨1.0 μmol/L组。阿司匹林3.0 mmol/L、卡培他滨1 μmol/L以及卡培他滨1.0 μmol/L＋阿司匹林3.0 mmol/L联合组电泳可以检测出环氧合酶-2（COX-2）、血管内皮生长因子（VEGF）的特异蛋白条带。阿司匹林单用时，COX-2表达量受到抑制（P<0.01），蛋白表达下调，而VEGF表达无明显抑制；卡培他滨单用时，VEGF表达量受到抑制（P<0.01），蛋白表达下调，而COX-2表达无明显抑制；卡培他滨联合阿司匹林处理时，SGC-7901细胞的COX-2、VEGF表达量均受到抑制（P<0.01），同时下调COX-2及VEGF蛋白表达。结论 卡培他滨联合阿司匹林能够明显抑制胃癌SGC-7901细胞的增殖，并促进其凋亡，其作用机制与COX-2、VEGF蛋白表达的调控有关。

Objective To investigate inhibitory effect of capecitabine combine with aspirin on proliferation of SGC 7901 cell in vitro and its mechanisms. Methods SGC-7901 cells were cultured in vitro. Inhibitory rates of capecitabine (1.0 μmol/L) or/and aspirin (0.5, 1.0, and 3.0 mmol/L) on SGC 7901 cell were detected by MTT method. The morphological changes of SGC-7901 cells treated by capecitabine (1.0 μmol/L) and aspirin (3.0 mmol/L) alone or in combination were observed by fluorescence microscopy. Apoptosis rates of SGC-7901 cells treated by capecitabine (1.0 μmol/L) and aspirin (3.0 mmol/L) alone or in combination were determined by Annexin VFIT C/PI kit and flow cytometry. The expressions of COX-2 and VEGF treated by capecitabine (1.0 μmol/L) and aspirin (3.0 mmol/L) alone or in combination were determined by Western blotting method. Results Capecitabine and aspirin all had inhibitory effects on growth of SGC-7901 cells, and the inhibition rates of combined group were higher than those in capecitabine group and aspirin group, with significant difference between two groups (P<0.05). Morphological changes of SGC-7901 cells were observed under microscope after treatment for 24 h, and changes in the combined group were more obvious than those in capecitabine group and aspirin group. Flow cytometry showed that apoptosis rates in the capecitabine (1.0 μmol/L)+aspirin (3.0 mmol/L) group was significantly higher than that of capecitabine (1.0 μmol/L) group or aspirin (3.0 mmol/L) group. The specific protein bands of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) in capecitabine (1.0 μmol/L) and aspirin (3.0 mmol/L) alone or in combination group could be detected by electrophoresis. When SGC-7901 cells were treated by aspirin alone, the expression of COX-2 was inhibited (P<0.01), and protein expression was down-regulated, but the expression of VEGF was not inhibited. While SGC-7901 cells were treated by capecitabine alone, the expression of VEGF was inhibited (P<0.01), and protein expression was down-regulated, but the expression of COX-2 was not inhibited. COX-2 and VEGF expression were inhibited when treated by capecitabine combined with aspirin (P<0.01), and the expression of COX-2 and VEGF protein were down-regulated. Conclusion Capecitabine combined with aspirin can significantly inhibit proliferation of SGC-7901 cell, and induce apoptosis, and its mechanism may be related to the regulation of COX-2 and VEGF protein expression.