干扰素α上调肝癌细胞胸苷磷酸化酶的表达及其机制  

Interferon-α upregulates thymidine phosphorylase expression via JAK-STAT transcriptional activation and mRNA stabilization in buman hepatocellular carcinoma SMMC-7721 cells

作　　者：肖永胜[1] 周俭[1] 樊嘉[1] 孙绮蛮[1] 赵燕[1] 孙瑞霞[1] 刘银坤[1] 汤钊猷[1] 

机构地区：[1]复旦大学附属中山医院肝癌研究所,上海200032

出　　处：《中华肿瘤杂志》2008年第6期444-447,共4页Chinese Journal of Oncology

基　　金：高等学校博士学科点专项科研基金资助项目（20030246052）;上海市教委基金资助项目（02JG05035）;复旦大学青年基金资助项目

摘　　要：目的探讨干扰素α（IFN—α）调控肝癌细胞SMMC-7721胸苷磷酸化酶（TP）表达的机制。方法应用逆转录聚合酶链反应（RT-PCR）检测SMMC-7721细胞中TP mRNA的表达水平；应用JAK-STAT信号通路阻断剂AG-490研究该通路的作用；应用基因转录抑制剂放线菌素D研究TP mRNA的半衰期。结果IFN-α上调TP mRNA表达具有时间-剂量依赖性。10000U／ml的IFN—α处理SMMC-7721细胞8h后，TP mRNA表达水平开始升高，至12h时峰值达0．7272±0．0582，此后维持在0．6573±0．1873水平至72h。5000U／ml和10000U／ml的IFN-α处理肝癌细胞24h，TP mRNA表达水平分别为0．5991±0．2179和0．6298±0．1786，与未用IFN—α处理的肝癌细胞（0．2231±0．0595）相比，差异有统计学意义（P〈0．05）。应用AG-490阻断JAK—STAT通路，IFN—α上调TP mRNA表达的能力明显受到抑制（0．2545±0．1053），与未处理的肝癌细胞（0．2329±0．1032）相比，差异不明显，仅应用IFN-α而未应用AG-490处理的肝癌细胞，其TP mRNA表达水平则显著升高（0．7209±0．1168）。应用IFN-α处理SMMC-7721细胞24h后，利用放线菌素D阻断RNA聚合酶，TP mRNA半衰期为35．8h，而未用IFN-Ot处理的肝癌细胞为8．5h。结论一定剂量的IFN-α上调TP mRNA的表达水平，与细胞内JAK-STAT信号通路有关；IFN—α具有转录后稳定TPmRNA的作用。Objective To examine how the thymidine phosphorylase （TP） gene expression is upregulated by interferon-α （IFN-α） in human hepatocellular carcinoma SMMC-7721 cells. Methods TP mRNA levels were determined by RT-PCR. Whether the JAK-STAT cascade mediates IFN-α-induced TP mRNA expression was studied by pretreatment with Janus Kinase （JAK） inhibitor, AG-490. Effects of IFN-α on TP mRNA stability were detected with additional actinomycin D. Results The expression of TP mRNA was induced by IFN-α in a dose- and time-dependent manner in SMMC-7721 （human hepatocellular carcinoma） cells. TP mRNA levels rose at 8 h, reached the peak value at 12 h, and remained at a high level up to 72 h in SMMC-7721 cells treated with IFN-α 10 000 U/ml. IFN-α at a dose of 5000 or 10 000 U/ml up-regulated TP expression about 3 fold compared with that of non-treated cells （ P 〈 0.05 ）. Induction of TP mRNA expression by IFN-α was significantly inhibited in SMMC-7721 cells by pretreatment with AG- 490, in comparison with that treated with IFN-α alone. Pretreatment of SMMC-7721 cells with IFN-α 10 000 U/ml for 24 h caused a substantial stabilization of TP mRNA, with a half-live of 35.8 h, compared with 8.5 hr in the control SMMC-7721 cells. Conclusion IFN-α at certain doses upregnlates TP mRNA expression via both JAK-STAT transcriptional activation and post-transcriptional mRNA stabilization in human hepatocellular carcinoma SMMC-7721 cells.

关 键 词：胸苷磷酸化酶 干扰素Α JAK—STAT信号通路 癌 肝细胞 

分 类 号：R686[医药卫生—骨科学]