Wu Kun, Zhao Yan, Li Gui-Chang, Yu Wei-Ping
Department of Nutrition and Food Hygiene, Public Health School, Harbin Medical University, Harbin 150001, Heilongjiang Province, China.
World J Gastroenterol. 2004 Apr 15;10(8):1110-4. doi: 10.3748/wjg.v10.i8.1110.
To investigate the roles of c-Jun N-terminal kinase (JNK) signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells.
Human gastric cancer cell lines (SGC-7901) were treated with vitamin E succinate (VES) at 5, 10, 20 mg/L. Succinic acid and vitamin E were used as vehicle controls and condition medium only as an untreated (UT) control. Apoptosis was observed by 4', 6-diamidine-2'-phenylindole dihydrochloride (DAPI) staining for morphological changes and by DNA fragmentation for biochemical alterations. Western blot analysis was applied to measure the expression of JNK and phosphorylated JNK. After the cells were transiently transfected with dominant negative mutant of JNK (DN-JNK) followed by treatment of VES, the expression of JNK and c-Jun protein was determined.
The apoptotic changes were observed after VES treatment by DNA fragmentation. DNA ladder in the 20 mg/L VES group was more clearly seen than that in 10 mg/L VES group and was not detected following treatment of UT control, succinate and vitamin E. VES at 5, 10 and 20 mg/L increased the expression of p-JNK by 2.5-, 2.8- and 4.2-fold, respectively. VES induced the phosphorylation of JNK beginning at 1.5 h and produced a sustained increase for 24 h with the peak level at 12 h. Transient transfection of DN-JNK blocked VES-triggered apoptosis by 52%. DN-JNK significantly increased the level of JNK, while decreasing the expression of VES-induced c-Jun protein.
VES-induced apoptosis in human gastric cancer SGC-7901 cells involves JNK signaling pathway via c-Jun and its downstream transcription factor.
探讨c-Jun氨基末端激酶（JNK）信号通路在维生素E琥珀酸酯诱导人胃癌SGC-7901细胞凋亡中的作用。
用人胃癌细胞系（SGC-7901）分别用5、10、20mg/L的维生素E琥珀酸酯（VES）处理。琥珀酸和维生素E用作溶剂对照，仅用条件培养基作为未处理（UT）对照。通过4',6-二脒基-2'-苯基吲哚二盐酸盐（DAPI）染色观察形态学变化来检测凋亡，通过DNA片段化检测生化改变。采用蛋白质免疫印迹分析检测JNK和磷酸化JNK的表达。细胞用JNK显性负性突变体（DN-JNK）瞬时转染后再用VES处理，然后检测JNK和c-Jun蛋白的表达。
VES处理后通过DNA片段化观察到凋亡变化。20mg/L VES组的DNA梯形条带比10mg/L VES组更清晰，未处理对照、琥珀酸和维生素E处理组未检测到。5、10和20mg/L的VES分别使p-JNK的表达增加2.5倍、2.8倍和4.2倍。VES在1.5小时开始诱导JNK磷酸化，并持续增加24小时，峰值出现在12小时。瞬时转染DN-JNK可使VES触发的凋亡减少52%。DN-JNK显著增加JNK水平，同时降低VES诱导的c-Jun蛋白表达。
VES诱导人胃癌SGC-7901细胞凋亡涉及通过c-Jun及其下游转录因子的JNK信号通路。
