中文摘要：

目的 观察吉西他滨（gemcitabine，GEM）处理膀胱癌T24细胞后引起凋亡的同时是否诱导T24细胞自噬的产生，并初步探究其自噬产生的机制,以及自噬与凋亡之间的关系。方法 体外培养T24细胞，应用CCK-8法测定细胞抑制率；Western blot检测凋亡相关蛋白Caspase-3、PARP的活化，自噬标志蛋白LC3-Ⅱ、底物蛋白P62和自噬潮，以及JNK通路相关蛋白Jnk1、P-Jnk、Bcl-2的表达情况；并通过透射电镜观察细胞超微结构自噬体的变化；Annexin V-PI双流式细胞术检测抑制自噬后细胞凋亡率的变化情况。结果 CCK-8检测结果显示吉西他滨能有效抑制膀胱癌T24细胞增殖；1.0 μg/mL吉西他滨处理T24细胞4 h即可发生明显的自噬，透射电镜观察可见自噬体小体的形成；Western blot检测结果显示吉西他滨作用T24细胞后cleaved-Caspase-3、PARP和LC3-Ⅱ表达增高，P62表达降低；P-Jnk出现活化，Bcl-2发生降解；而抑制自噬后能显著增强吉西他滨诱导的膀胱癌T24细胞的凋亡。结论 吉西他滨介导膀胱癌T24细胞凋亡的同时又诱导保护性自噬，JNK信号通路参与调控其自噬的发生，抑制自噬可以明显增强膀胱癌T24细胞对吉西他滨的化疗敏感性。

英文摘要：

Objective To investigate whether gemcitabine （GEM） will activate autophagy when GEM induced apoptosis in human bladder cancer T24 cells, and explore the underlying mechanism and the relationship between autophagy and apoptosis induced by GEM. Methods Cell counting kit-8 （CCK-8） assay was used to detect the growth inhibition in human bladder cancer T24 cells after GEM treatment. Western blotting was used to detect the apoptosis related proteins Caspase-3 and PARP, autophagy marker proteins LC3-Ⅱ, P62 and autophagy flux, and JNK signaling pathway related proteins Jnk1, P-Jnk and Bcl-2. Transmission electron microscopy （TEM） was employed to observe the intracellular autophagosome. Flow cytometry （FCM） was used to measure cell apoptosis with aid of Annexin V-FITC apoptosis detection kit after inhibition of autophagy. Results CCK-8 assay revealed that GEM effectively inhibited the proliferation of T24 cells. GEM treatment of 1.0 μg/mL resulted in obvious autophagy in the cells, and TEM displayed the formation of intracellular autophagosome. The results Western blotting showed the expression levels of cleaved-Caspase-3, PARP and LC3-Ⅱ were elevated, while that of p62 was reduced after GEM treatment. GEM also phosphorylated JNK and suppressed Bcl-2 to activate JNK signaling pathway. Inhibition of autophagy could enhance cell apoptosis in T24 cells after GEM treatment. Conclusion GEM induces cell apoptosis in T24 cells, and also induces autophagy to protect the cells against apoptosis at the same time. JNK signaling pathway is involved in the regulation of autophagy, and inhibition of autophagy will significantly enhance the chemosensitivity of T24 cells to GEM.