目的：探讨X射线激发Cu-Cy介导的光动力对人结肠癌SW620细胞的体外杀伤效应及其作用机制。方法：用不同浓度（0~100 mg/L）Cu-Cy联合或不联合低剂量X线照射处理SW620细胞后，采用CCK8法检测并光镜观察细胞的生长活性；JC-1染色检测线粒体膜电位；AnnexinV FIFC/PI双染法检测细胞的凋亡率；Western blot检测凋亡相关蛋白Bax、Bcl-2及自噬相关蛋白LC3B、P62的表达；透射电镜观察细胞的超微结构。结果：与空白对照SW620细胞（0 mg/L Cu-Cy，无X线照射），Cu-Cy联合X线照射处理的SW620细胞生长活性明显降低，并呈一定的浓度依赖性（部分P<0.05），且细胞凋亡率明显升高、线粒体膜电位下降细胞的比例明显增加、Bax与LC3B-II蛋白表达明显升高，Bcl-2与P62蛋白表达明显降低（均P<0.05）、细胞内自噬体增多；单纯X射线照射和单加Cu-Cy处理的SW620细胞以上指标均无明显改变。结论：X线激发Cu-Cy介导的光动力能有效抑制人结肠癌SW620细胞体外生长活性，机制可能与其诱导细胞凋亡和自噬有关。
Photodynamic killing effect mediated by Cu-Cy under X-ray activation on colon cancer cells and the mechanism
Objective: To investigate the photodynamic killing effect mediated by Cu-Cy under X-ray activation on human colon cancer SW620 cells in vitro and the mechanism. Methods: SW620 cells were exposed to different concentrations of Cu-Cy (0–100 mg/L) in combination with or without low dose of X-ray radiation, and then, the cell viability was examined by CCK8 assay and light microscopic observation, mitochondrial membrane potential was detected by JC-1 dye, apoptosis was measured by Annexin V/PI double-staining, the expressions of apoptosis-associated protein Bax and Bcl-2, and autophagy-associated protein LC3B and P62 were determined by Western blot analysis, and cell ultrastructure was observed by transmission electron microscopy. Results: In SW620 cells compared with blank control SW620 cells (without Cu-Cy treatment and X-ray radiation), the cell viability was significantly reduced with certain concentration-dependent manner (part P<0.05), and meanwhile, the ratio of cells with decreased mitochondrial membrane potential and the apoptotic rate were significantly increased, the expression levels of Bax and LC3B-II were significantly increased while the expression levels of Bcl-2 and P62 were significantly decreased (all P<0.05), and the intracellular autophagosomes were remarkably increased; all above indexes showed no significant change in those cells that underwent X-ray radiation alone or Cu-Cy treatment alone. Conclusion: The photodynamic action mediated by Cu-Cy under X-ray activation can effectively inhibit the growth and viability of human colon cancer SW620 cells in vitro, and the mechanism may possibly be associated with its inducing apoptosis and autophagy.