细胞自噬对紫杉醇诱导宫颈癌CaSki细胞死亡的影响

目的：通过对自噬基因Beclin1的表达调节来观察细胞自噬对紫杉醇诱导人宫颈癌CaSki细胞株死亡的影响，并探讨在该过程中自噬与凋亡之间的相互作用及关系。方法：利用脂质体法将Beclin1的过表达质粒pcDNA3.1-Beclin1和RNA干扰质粒pSUPER-Beclin1分别体外转染CaSki细胞并筛选稳定表达株后，电镜下观察细胞内自噬囊泡的形成，Western 印迹检测转染前后Beclin1与LC3蛋白的表达变化。上述细胞株经紫杉醇作用后MTT法检测细胞增殖情况的改变，流式细胞仪检测自噬细胞与凋亡细胞的百分率。结果：在Beclin1基因过度表达的CaSki细胞株中，电镜观察到细胞内存在大量的自噬囊泡；Beclin1与LC3蛋白的表达在pcDNA3.1-Beclin1转染细胞株中被上调。MTT法检测提示Beclin1过表达细胞株存活细胞明显少于未转染对照细胞株。流式细胞仪检测提示经紫杉醇作用后与空白对照组比较，Beclin1过表达组自噬细胞与凋亡细胞百分率均有明显增加，其中凋亡增加尤其明显；而Beclin1干扰组自噬细胞与凋亡细胞百分率均有所减少。结论：在紫杉醇对宫颈癌CaSki细胞株的杀伤过程中细胞自噬与凋亡均发挥了作用，在Beclin1基因过度表达的CaSki细胞株中可通过增加紫杉醇诱导的细胞凋亡来增强药物对肿瘤细胞的杀伤作用。

Effect of autophagy on paclitaxel-induced CaSki cell death

Objective To observe the effect of autophagy on paclitaxel-induced CaSki cell death through the regulation of the expression of autophagy gene Beclin1, and to explore the interaction and relationship between autophagy and apoptosis. Methods Eukaryotic expression vector pcDNA3.1-Beclin1 and RNA interference vector pSUPER-Beclin1 were transfected into human cervical cancer CaSki cells in vitro and screened for stable expression cell lines. The formation of autophagic vacuoles was observed with an electronic microscope. The expression of Beclin1 and LC3 was measured by Western blot. After being treated with paclitaxel, the change of cell proliferation was assessed by MTT assay, the percentage of apoptotic cells and autophagic cells were analyzed by flow cytometry. Results A lot of autophagic vacuoles were observed in pcDNA3.1-Beclin1 cells by electronic microscopy. Beclin1 and LC3 protein expression was up-regulated in CaSki cells transfected with pcDNA3.1-Beclin1, and was inhibited in cells transfected with pSUPER-Beclin1. MTT assay revealed the survival rate of CaSki cells was significantly decreased after being transfected with pcDNA3.1-Beclin1. After being treated with paclitaxel, the percentages of apoptotic cells and autophagic cells were both increased in pcDNA3.1-Beclin1 group compared with that of the blank control group especially the increase of apoptosis was particularly evident. Conclusion Autophagy and apoptosis have different roles in the process of paclitaxel-induced cervical cancer CaSki cell line death. Overexpression of Beclin1 in CaSki cells may enhance the apoptosis induced by paclitaxel.