原卟啉Ⅸ-声动力学疗法诱导S180肿瘤细胞的凋亡

Apoptosis on S180 tumor cells induced by ultrasonically-activated protoporphyrin Ⅸ

采用频率为2.2MHz,声强为3W/cm2的低强度聚焦超声结合原卟啉Ⅸ对S180肿瘤细胞的损伤以及诱导细胞凋亡的发生进行研究,并探讨其作用的分子机制。超声激活原卟啉Ⅸ作用于S180肿瘤细胞处理后,不同时间段取材,通过Annexin V-PI荧光双染观察凋亡细胞的形态学变化;采用TUNEL末端标记法检测细胞凋亡的发生率;利用间接免疫荧光技术和免疫细胞化学技术检测细胞内凋亡相关蛋白Caspase-8、Caspase-3以及死亡底物聚ADP核糖聚合酶[poly(ADP-ribose)polymerase,PARP]的表达活性变化。实验结果显示:超声激活原卟啉Ⅸ可以诱导S180肿瘤细胞凋亡的发生,并且凋亡细胞的比例随着取材时间的延迟明显增加;免疫细胞化学染色表明声动力学处理显著增强了细胞内Caspase-8和Caspase-3的蛋白表达活性,并且其活化程度分别于处理后1h和3h达到最高,而死亡底物PARP也发生时间相关性剪切。研究表明,超声结合原卟啉Ⅸ可以通过诱导细胞凋亡的方式发挥其抗肿瘤活性,其作用的分子机制可能涉及到膜受体介导的Caspase-8。

The effects of proptoporphyria Ⅸ （pp Ⅸ ） combined with focused untrasound on cellular death （apoptosis） in S180 tumour cells were studied, and the mechanism responsible for induction of apoptosis was evaluated. An annexin V-PI apoptosis detecting kit was used to identify morphological changes in S180 cells at various times after treatment. The extent of apoptosis was analysed by terminal deoxynucleotidyl transferase-mediated dUTP-digoxin nick and labeling （TUNEL） staining. Expression of apoptosiarelated proteins （Caspase-3, Caspase-8 and poly ADP-fibose polymerase （PARP）） was determined by immunohistochemistry. Results indicated that apoptosis in S180 tumour cells can be induced by ultrasonically-activated protoporphyfin Ⅸ, and that the rate of apoptosis increased gradually over time, post-treatment. Activation of Caspase-8 and Caspase-3 were upregulated during apoptosis and PARP was cleaved to its active segment, in a time-dependent manner. Thes results indicate that sonochemically activated protoporphyrin Ⅸ may exert its anti-tumour activity by triggering apoptosis in S180 cells. The probable mechanism underlying this effect involves expression of Caspase-8, Caspase-3, and PARP cleaving actions, which are dependent upon membrane receptor activating pathways.