Transforming growth factor-β1 (TGF-β)-induced apoptosis of prostate cancer cells involves Smad7-dependent activation of p38 by TGF-β-activated kinase 1 and mitogen-activated protein kinase kinase 3
Transforming growth factor-β1 (TGF-β)-induced apoptosis of prostate cancer cells involves Smad7-dependent activation of p38 by TGF-β-activated kinase 1 and mitogen-activated protein kinase kinase 3
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DOI：
10.1091/mbc.02-03-0037
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发表时间：
2003-02-01
影响因子：
3.3
通讯作者：
Landström, M
中科院分区：
文献类型：
--
作者：
Edlund, S;Bu, SH;Landström, M
Smad7是转化生长因子- β (tgf - β)的直接靶基因，在多种细胞类型中介导tgf - β 1诱导的细胞凋亡。本文中，我们报道了tgf - β 1或Smad7过表达诱导的人前列腺癌PC-3U细胞凋亡是由p38丝裂原活化蛋白激酶途径以tgf - β -活化激酶1 （TAK1）和丝裂原活化蛋白激酶3 （MKK3）依赖的方式特异性激活引起的。表达显性阴性p38、显性阴性MKK3，或与p38选择性抑制剂[4-（4-氟苯基）-2-（4-甲基亚砜基苯基）-5-（4-吡啶基）1h -咪唑]孵育，均可阻止tgf - β 1诱导的细胞凋亡。tgf - β诱导的MKK3和p38激酶激活需要Smad7的表达，并且发现内源性Smad7以配体依赖的方式与磷酸化的p38相互作用。野生型TAK1的异位表达促进了tgf - β 1诱导的p38磷酸化和细胞凋亡，而显性负TAK1则降低了tgf - β 1诱导的p38磷酸化和细胞凋亡。发现内源性Smad7与TAK1相互作用，TAK1、MKK3和p38在瞬时转染的COS1细胞中与Smad7共免疫沉淀。此外，异位表达的Smad7增强了HA-MKK3和Flag-p38的共免疫沉淀，支持了Smad7可能作为支架蛋白并促进TAK1-和mkk3介导的p38激活的观点。
The inhibitory Smad7, a direct target gene for transforming growth factor-beta (TGF-beta), mediates TGF-beta1-induced apoptosis in several cell types. Herein, we report that apoptosis of human prostate cancer PC-3U cells induced by TGF-beta1 or Smad7 overexpression is caused by a specific activation of the p38 mitogen-activated protein kinase pathway in a TGF-beta-activated kinase 1 (TAK1)- and mitogen-activated protein kinase kinase 3 (MKK3)-dependent manner. Expression of dominant negative p38, dominant negative MKK3, or incubation with the p38 selective inhibitor [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole], prevented TGF-beta1-induced apoptosis. The expression of Smad7 was required for TGF-beta-induced activation of MKK3 and p38 kinases, and endogenous Smad7 was found to interact with phosphorylated p38 in a ligand-dependent manner. Ectopic expression of wild-type TAK1 promoted TGF-beta1-induced phosphorylation of p38 and apoptosis, whereas dominant negative TAK1 reduced TGF-beta1-induced phosphorylation of p38 and apoptosis. Endogenous Smad7 was found to interact with TAK1, and TAK1, MKK3, and p38 were coimmunoprecipitated with Smad7 in transiently transfected COS1 cells. Moreover, ectopically expressed Smad7 enhanced the coimmunoprecipitation of HA-MKK3 and Flag-p38, supporting the notion that Smad7 may act as a scaffolding protein and facilitate TAK1- and MKK3-mediated activation of p38.