【摘要】 目的 探讨灰树花多糖对增强人肿瘤细胞放射治疗敏感性的作用，研究灰树花多糖与X-射线联合使用后细胞凋亡相关基因Bax的mRNA表达水平的变化并探讨两者协同作用的分子机理。方法 用CCK-8方法测定灰树花多糖与X-射线联合处理后HCT116的细胞存活率(cell survival rate,CSR)；用Apoptosis Ladder Detection Kit进行灰树花多糖与X-射线联合处理后细胞凋亡检测；用RT-PCR方法测定Bax 基因的表达。结果 (1)灰树花多糖与X-射线联合处理对肿瘤细胞的直接杀伤作用高于X-射线单独处理；(2)X射线与灰树花多糖联合处理时细胞发生凋亡；(3)X-射线与灰树花多糖联合处理后细胞发生凋亡的分子机理与细胞凋亡相关基因Bax的表达提高相关。结论 灰树花多糖对肿瘤放射治疗具有明显的增敏作用，联合使用可诱导肿瘤细胞凋亡，此作用可能与凋亡相关基因Bax的表达增加相关。

     【关键词】 灰树花多糖；X-射线；细胞凋亡；Bax

    A Polysaccharide from Grifola frondosa Promotes X-ray induced cell apoptosis through upregulation of Bax in HCT116 cells

    CAO Wei-guo,JIANG Jin-song,MA Tao,et al.Department of Irradiation and Chemotherapy,Reijin Hospital,Shanghai 200025,China

    【Abstract】 Objective To explore the efficiency of the polysaccharide extracted from Grifola frondosa, in enhancing sensitivity to X-ray irradiation in human colon cancer cells HCT116. The levels of Bax mRNA were investigated in the treatment of the polysaccharide extracted from Grifola frondosa combinated with X-ray treatment to demonstrate the molecular basis for the synergistic effects.Methods HCT116 cell survival rate were monitored by CCK-8 kit. Apoptosis was detected with Apoptosis Ladder Detection Kit in the agarose gel electrophoresis. Bax gene expression was checked by semiquantitative PCR analysis of cellular RNA. Results Here we showed the sensitivity to X-irradiation was detected an increase in the combination of the polysaccharide extracted from Grifola frondosa and X-ray, comparing to X-ray alone. Moreover, the effect of the polysaccharide extracted from Grifola frondosa combined with X-ray on apoptosis was observed by DNA-ladder formation. We also present the evidence that pro-apoptotic gene Bax expresion may be involved in augmented the polysaccharide extracted from Grifola frondosa induced HCT116 cells sensitivity to X-ray irradiation.Conclusion The sensitivity to X-irradiation was increased in the combination of the polysaccharide from Grifola frondosa and X-ray. Moreover, the effect of the polysaccharide from Grifola frondosa combined with X-ray on apoptosis was observed and pro-apoptotic gene Bax expresion may be involved in augmented the polysaccharide extracted from Grifola frondosa induced HCT116 cells sensitivity to X-ray irradiation. ......