Madauss Kevin P, Grygielko Eugene T, Deng Su-Jun, Sulpizio Anthony C, Stanley Thomas B, Wu Charlene, Short Steve A, Thompson Scott K, Stewart Eugene L, Laping Nicholas J, Williams Shawn P, Bray Jeffrey D
Department of Computational, Analytical and Structural Sciences, GlaxoSmithKline Discovery Research, Research Triangle Park, North Carolina 27709, USA.
Mol Endocrinol. 2007 May;21(5):1066-81. doi: 10.1210/me.2006-0524. Epub 2007 Mar 13.
Selective progesterone receptor modulators (SPRMs) have been suggested as therapeutic agents for treatment of gynecological disorders. One such SPRM, asoprisnil, was recently in clinical trials for treatment of uterine fibroids and endometriosis. We present the crystal structures of progesterone receptor (PR) ligand binding domain complexed with asoprisnil and the corepressors nuclear receptor corepressor (NCoR) and SMRT. This is the first report of steroid nuclear receptor crystal structures with ligand and corepressors. These structures show PR in a different conformation than PR complexed with progesterone (P4). We profiled asoprisnil in PR-dependent assays to understand further the PR-mediated mechanism of action. We confirmed previous findings that asoprisnil demonstrated antagonism, but not agonism, in a PR-B transfection assay and the T47D breast cancer cell alkaline phosphatase activity assay. Asoprisnil, but not RU486, weakly recruited the coactivators SRC-1 and AIB1. However, asoprisnil strongly recruited the corepressor NCoR in a manner similar to RU486. Unlike RU486, NCoR binding to asoprisnil-bound PR could be displaced with equal affinity by NCoR or TIF2 peptides. We further showed that it weakly activated T47D cell gene expression of Sgk-1 and PPL and antagonized P4-induced expression of both genes. In rat leiomyoma ELT3 cells, asoprisnil demonstrated partial P4-like inhibition of cyclooxygenase (COX) enzymatic activity and COX-2 gene expression. In the rat uterotrophic assay, asoprisnil demonstrated no P4-like ability to oppose estrogen. Our data suggest that asoprisnil differentially recruits coactivators and corepressors compared to RU486 or P4, and this specific cofactor interaction profile is apparently insufficient to oppose estrogenic activity in rat uterus.
选择性孕激素受体调节剂（SPRMs）已被提议作为治疗妇科疾病的药物。其中一种SPRMs，阿索普瑞尼，最近正处于治疗子宫肌瘤和子宫内膜异位症的临床试验阶段。我们展示了与阿索普瑞尼以及共抑制因子核受体共抑制因子（NCoR）和SMRT复合的孕激素受体（PR）配体结合域的晶体结构。这是类固醇核受体与配体和共抑制因子的晶体结构的首次报道。这些结构显示PR处于与与孕酮（P4）复合的PR不同的构象。我们在PR依赖性试验中对阿索普瑞尼进行了分析，以进一步了解PR介导的作用机制。我们证实了先前的发现，即在PR-B转染试验和T47D乳腺癌细胞碱性磷酸酶活性试验中，阿索普瑞尼表现出拮抗作用而非激动作用。阿索普瑞尼而非RU486，微弱地募集了共激活因子SRC-1和AIB1。然而，阿索普瑞尼以类似于RU486的方式强烈募集了共抑制因子NCoR。与RU486不同，NCoR与结合阿索普瑞尼的PR的结合可以被NCoR或TIF2肽以相同亲和力取代。我们进一步表明，它微弱地激活了T47D细胞中Sgk-1和PPL的基因表达，并拮抗了P4诱导的这两个基因的表达。在大鼠平滑肌瘤ELT3细胞中，阿索普瑞尼表现出部分类似P4的对环氧合酶（COX）酶活性和COX-2基因表达的抑制作用。在大鼠子宫增重试验中，阿索普瑞尼没有表现出类似P4的对抗雌激素的能力。我们的数据表明，与RU486或P4相比，阿索普瑞尼对共激活因子和共抑制因子的募集存在差异，并且这种特定的辅因子相互作用模式显然不足以对抗大鼠子宫中的雌激素活性。
