手霉素对甲状腺癌KAT-18细胞的作用及其机制

Effects and the mechanism of manumycin on KAT-18 anaplastic thyroid cancer cells

目的:探讨手霉素对甲状腺未分化癌KAT-18细胞株的作用及其机制。方法:使用SRB细胞毒性测定法评价KAT-18细胞的活性,使用Annexin v和一氧化氮(NO)染料标记细胞,应用流式细胞术检测细胞内NO生成和细胞凋亡,二氢乙啶(DHE)方法测定细胞内超氧阴离子。应用化学发光法测定超氧歧化酶(SOD)活性,Mn-SOD的表达采用免疫印迹技术检测。谷胱甘肽(GSH)含量采用荧光法测定。结果:手霉素有效杀伤KAT-18细胞,随着手霉素剂量的增加,细胞活性逐渐下降。手霉素诱导产生NO和超氧阴离子,降低GSH,但不影响Mn-SOD的蛋白表达和6 h的SOD活性,但24 h的SOD活性代偿性增加。手霉素诱导的凋亡与NO和超氧阴离子增加及GSH下降有关。用N-乙酰基-L-半胱氨酸(N-acetyl-L-cysteine,NAC)抑制NO和超氧阴离子产生,提高GSH可减少手霉素诱导KAT-18细胞凋亡,从而逃避细胞被手霉素杀伤。结论:手霉素通过细胞内NO和超氧阴离子的产生诱导甲状腺癌细胞凋亡,杀伤甲状腺癌细胞。

Objective To explore the effects and the mechanism of manumycin on KAT-18 cells Methods Human ATC（anaplastic thyroid cancer） KAT-18 cells were used. The cytotoxicity was analyzed by SRB assay. Apoptosis and cellular nitric oxide were detected by flow cytometry using annexin v and NO sensor dye. Superoxide anion was measured with a fluorescent plate reader by DHE.GSH was assayed by fluorescent Monochlorobimane. The SOD activities were assayed by colorimetric methods. The protein expression of Mn-SOD was determined by western blot. Results Manumycin decreased the viability of KAT-18 cells in a dosedependent manner. Manumycin induced apoptosis significantly and NO generation simultaneously. Manumycin also induced superoxide anions generation. Manumycin reduced intracellular GSH in a time-course manner. However,manumycin did not decrease the SOD activity after 6 h treatment and Mn-SOD expression. A delayed induction of SOD activity was observed after 24 h manumycin treatment. N-acetyl-L-cysteine blocked NO and superoxide anions generation and apoptosis induction by Manumycin. Furthermore, NAC protected KAT-18 cells from the cytotoxicity of manumycin. Conclusion Manumycin induces apoptosis and has cytotoxic effects on KAT-18 cells.Cellular NO and superoxide anions generation are required for Manumycin-induced apoptosis in KAT-18 cells.