Ponnusamy Suriyan, Coss Christopher C, Thiyagarajan Thirumagal, Watts Kate, Hwang Dong-Jin, He Yali, Selth Luke A, McEwan Iain J, Duke Charles B, Pagadala Jayaprakash, Singh Geetika, Wake Robert W, Ledbetter Christopher, Tilley Wayne D, Moldoveanu Tudor, Dalton James T, Miller Duane D, Narayanan Ramesh
Department of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee.
GTx, Inc., Memphis, Tennessee.
Cancer Res. 2017 Nov 15;77(22):6282-6298. doi: 10.1158/0008-5472.CAN-17-0976. Epub 2017 Oct 4.
Androgen receptor (AR) mediates the growth of prostate cancer throughout its course of development, including in abnormal splice variants (AR-SV)-driven advanced stage castration-resistant disease. AR stabilization by androgens makes it distinct from other steroid receptors, which are typically ubiquitinated and degraded by proteasomes after ligand binding. Thus, targeting AR in advanced prostate cancer requires the development of agents that can sustainably degrade variant isoforms for effective therapy. Here we report the discovery and characterization of potent selective AR degraders (SARD) that markedly reduce the activity of wild-type and splice variant isoforms of AR at submicromolar doses. Three SARDs (UT-69, UT-155, and (R)-UT-155) bind the amino-terminal transcriptional activation domain AF-1, which has not been targeted for degradation previously, with two of these SARD (UT-69 and UT-155) also binding the carboxy-terminal ligand binding domain. Despite different mechanisms of action, all three SARDs degraded wild-type AR and inhibited AR function, exhibiting greater inhibitory potency than the approved AR antagonists. Collectively, our results introduce a new candidate class of next-generation therapeutics to manage advanced prostate cancer. .
雄激素受体(AR)在前列腺癌整个发展过程中介导其生长,包括在异常剪接变体(AR-SV)驱动的晚期去势抵抗性疾病中。雄激素对AR的稳定作用使其有别于其他类固醇受体,后者通常在配体结合后被蛋白酶体泛素化并降解。因此,在晚期前列腺癌中靶向AR需要开发能够可持续降解变体亚型以实现有效治疗的药物。在此,我们报告了强效选择性AR降解剂(SARD)的发现和特性,这些降解剂在亚微摩尔剂量下能显著降低AR野生型和剪接变体亚型的活性。三种SARD(UT-69、UT-155和(R)-UT-155)与氨基末端转录激活域AF-1结合,该区域此前未被作为降解靶点,其中两种SARD(UT-69和UT-155)还与羧基末端配体结合域结合。尽管作用机制不同,但所有三种SARD均能降解野生型AR并抑制AR功能,其抑制效力比已获批的AR拮抗剂更强。总体而言,我们的结果引入了一类新的下一代治疗候选药物来治疗晚期前列腺癌。