The androgen receptor represses transforming growth factor-β signaling through interaction with Smad3
The androgen receptor represses transforming growth factor-β signaling through interaction with Smad3
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DOI：
10.1074/jbc.m108855200
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发表时间：
2002-01-11
影响因子：
4.8
通讯作者：
Danielpour, D
中科院分区：
文献类型：
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作者：
Chipuk, JE;Cornelius, SC;Danielpour, D
在前列腺中，雄激素通过未知机制负调节转化生长因子-β（TGF-β）配体和受体的表达以及Smad活化。我们发现，雄激素（二氢睾酮和R1881）下调TGF-β 1诱导的TGF-β 1，c-Fos和Egr-1在人前列腺腺癌细胞系，LNCaP的表达。此外，5 α-二氢睾酮（DHT）抑制LNCaP细胞中三种TGF-β 1响应性启动子结构（3 TP-荧光素酶、AP-1-荧光素酶和SBE 4（BV）-荧光素酶）的TGF-β 1激活，无论是否强制表达TGF-β受体（TbetaRI和TbetaRII）。类似地，DHT通过组成型激活的TbetaRI（T204 D）或组成型激活的Smad 3（S3*）抑制Smad结合元件（SBE）4（BV）-荧光素酶的激活。在NRP-154前列腺细胞系中，S3* 对SBE 4（BV）-荧光素酶的激活，该细胞系为雄激素受体（AR）阴性但对TGF-β 1高度应答，通过与全长AR或缺失DNA结合结构域的AR共转染来阻断。免疫沉淀和GST下拉试验表明，AR直接与Smad 3，但不与Smad 2或Smad 4。电泳迁移率变动分析表明，AR配体结合域直接抑制协会的Smad 3的Smad结合元件。总之，我们的数据首次表明，配体结合的AR通过选择性抑制Smad 3与SBE的结合来抑制TGF-β的转录反应。
In the prostate, androgens negatively regulate the expression of transforming growth factor-beta (TGF-beta) ligands and receptors and Smad activation through unknown mechanisms. We show that androgens (dihydrotestosterone and R1881) down-regulate TGF-beta1-induced expression of TGF-beta1, c-Fos, and Egr-1 in the human prostate adenocarcinoma cell line, LNCaP. Moreover, 5alpha-dihydrotestosterone (DHT) inhibits TGF-beta1 activation of three TGF-beta1-responsive promoter constructs, 3TP-luciferase, AP-1-luciferase, and SBE4(BV)-luciferase, in LNCaP cells either with or without enforced expression of TGF-beta receptors (TbetaRI and TbetaRII). Similarly, DHT inhibits the activation of Smad-binding element (SBE)4(BV)-luciferase by either constitutively activated TbetaRI (T204D) or constitutively activated Smad3 (S3*). Activation of SBE4(BV)-luciferase by S3* in the NRP-154 prostatic cell line, which is androgen receptor (AR)-negative but highly responsive to TGF-beta1, is blocked by co-transfection with either full-length AR or AR missing the DNA binding domain. Immunoprecipitation and GST pull-down assays show that AR directly associates with Smad3 but not Smad2 or Smad4. Electrophoretic mobility shift assays indicate that the AR ligand binding domain directly inhibits the association of Smad3 to the Smad-binding element. In conclusion, our data demonstrate for the first time that ligand-bound AR inhibits TGF-beta transcriptional responses through selectively repressing the binding of Smad3 to SBE.