目的 探讨Bag1表达水平对胃癌细胞生长和对5-氟尿嘧啶（5-FU）敏感性的影响。方法 采用Real-Time PCR和Western blotting 检测Bag1在5个不同的胃癌细胞系中的表达水平。选取高表达Bag1的细胞系，采用慢病毒载体下调Bag1基础表达水平，下调效率经Real-Time PCR和Western blotting检测验证；采用CCK-8法检测Bag1表达水平下调对细胞生长及对5-FU敏感性的影响。结果 Bag1 mRNA和蛋白表达水平在SGC7901和KATO-Ⅲ细胞中均显著升高。有效下调Bag1的表达水平后，SGC7901和KATO-Ⅲ细胞增殖受到抑制，而对5-FU的敏感性显著提高。结论 沉默Bag1基因可显著抑制胃癌细胞增殖，增强细胞对5-FU的敏感性。Bag1可能成为胃癌化学治疗的新靶点。

Objective To investigate the effects of Bag1 expression level on the growth of gastric cancer cells and chemo-sensitivity to 5-fluorouracil (5-FU). Methods The expression levels of Bag1 in five different gastric cancer cell lines were determined by Real-Time PCR and Western blotting. Cells with highly expressed Bag1 were selected and the basic expression level of Bag1 was down-regulated by the lentiviral shRNA. The efficiency of Bag1 silencing was confirmed by Real-Time PCR and Western blotting. The effects of the Bag1 knockdown on cell proliferation and chemo-sensitivity to 5-FU were detected by CCK-8 method. Results The expression levels of mRNA and protein of Bag1 were significantly increased in SGC7901 and KATO-Ⅲ cells. Efficient knockdown of Bag1 resulted in suppressing the proliferation of SGC7901 and KATO-Ⅲ cells and significantly enhancing the chemo-sensitivity to 5-FU. Conclusion Knockdown of Bag1 can significantly suppress the proliferation of gastric tumor cells and enhance chemo-sensitivity to 5-FU. Bag1 could be a new therapeutic target for chemotherapy of GC.