Department of Laboratory Medicine, Taipei Medical University-Wan Fang Hospital; Department of Pathology, Taipei Medical University-Shuang Ho Hospital, Taipei 116, Taiwan.
J Biochem. 2010 May;147(5):645-50. doi: 10.1093/jb/mvp213. Epub 2010 Jan 6.
Interferon alpha (IFN-alpha) modulates the proliferation of different human tumour cell lines. It has been shown that IFN-alpha induces the growth inhibition of T-cell acute lymphoblastic leukaemia (T-ALL). However, its intracellular signalling mechanisms remain unknown. This study found that IFN-alpha inhibited the cell proliferation of human T-ALL cell line Jurkat in a dose- and time-dependent manner. A p38 inhibitor (SB203580), but not an extracellular signal-regulated kinase 1/2 inhibitor (PD98059) or c-Jun N-terminal kinase inhibitor (SP600125), eliminated IFN-alpha inhibition of Jurkat cell proliferation, indicating that p38 pathway is crucial for IFN-alpha-mediated growth inhibition. SB203580 targeted two p38 isoforms, p38alpha and p38beta. The expression of p38alpha and p38beta mRNA in Jurkat cells was examined by reverse transcriptase-polymerase chain reaction. The kinase activity of p38alpha and p38beta was activated by IFN-alpha in Jurkat cells. To investigate the role of p38alpha and p38beta isoforms in IFN-alpha-mediated growth inhibition, we generated stable clones that overexpressed the dominant-negative p38 isoform, p38alpha(AF) or p38beta(AF), in Jurkat cells. Overexpression of p38alpha(AF) or p38beta(AF) inhibited IFN-alpha-mediated p38 kinase activity and growth inhibition in Jurkat cells. Similarly, down-regulation of either p38alpha or p38beta by isoform-specific small interference RNAs also reduced IFN-alpha-mediated growth inhibition. These results demonstrate that IFN-alpha can regulate growth inhibition of Jurkat cells through p38alpha and p38beta.
干扰素 alpha（IFN-alpha）调节不同人类肿瘤细胞系的增殖。已经表明 IFN-alpha 诱导 T 细胞急性淋巴细胞白血病（T-ALL）的生长抑制。然而，其细胞内信号转导机制仍不清楚。本研究发现 IFN-alpha 以剂量和时间依赖的方式抑制人 T-ALL 细胞系 Jurkat 的细胞增殖。p38 抑制剂（SB203580），但不是细胞外信号调节激酶 1/2 抑制剂（PD98059）或 c-Jun N 末端激酶抑制剂（SP600125），消除了 IFN-alpha 对 Jurkat 细胞增殖的抑制，表明 p38 途径对于 IFN-alpha 介导的生长抑制至关重要。SB203580 靶向两种 p38 同工型，p38alpha 和 p38beta。通过逆转录聚合酶链反应检查 Jurkat 细胞中 p38alpha 和 p38beta mRNA 的表达。IFN-alpha 在 Jurkat 细胞中激活 p38alpha 和 p38beta 的激酶活性。为了研究 p38alpha 和 p38beta 同工型在 IFN-alpha 介导的生长抑制中的作用，我们在 Jurkat 细胞中生成了稳定的克隆，该克隆过表达了显性负性 p38 同工型 p38alpha(AF)或 p38beta(AF)。p38alpha(AF)或 p38beta(AF)的过表达抑制了 Jurkat 细胞中 IFN-alpha 介导的 p38 激酶活性和生长抑制。同样，通过同工型特异性小干扰 RNA 下调任一 p38alpha 或 p38beta 也降低了 IFN-alpha 介导的生长抑制。这些结果表明 IFN-alpha 可以通过 p38alpha 和 p38beta 调节 Jurkat 细胞的生长抑制。
