Targeting the Hsp40/Hsp70 Chaperone Axis as a Novel Strategy to Treat Castration-Resistant Prostate Cancer.
Targeting the Hsp40/Hsp70 Chaperone Axis as a Novel Strategy to Treat Castration-Resistant Prostate Cancer.
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DOI：
10.1158/0008-5472.can-17-3728
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发表时间：
2018-07-15
期刊：
影响因子：
11.2
通讯作者：
Neckers LM
中科院分区：
文献类型：
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作者：
Moses MA;Kim YS;Rivera-Marquez GM;Oshima N;Watson MJ;Beebe KE;Wells C;Lee S;Zuehlke AD;Shao H;Bingman WE 3rd;Kumar V;Malhotra SV;Weigel NL;Gestwicki JE;Trepel JB;Neckers LM
去势抵抗性前列腺癌（CRPC）的特征在于雄激素受体（AR）信号传导的再激活，部分地通过AR剪接变体（ARv）的表达升高，包括ARv 7，ARv 7是一种组成型活性的配体结合结构域（LBD）缺陷变体，其表达与治疗抗性和不良预后相关。在筛选以鉴定雄激素依赖性和雄激素非依赖性AR基因特征的小分子双重抑制剂时，我们鉴定了查耳酮C86。使用纯化的蛋白质和CRPC细胞裂解物的结合研究显示C86与热休克蛋白40（Hsp 40）相互作用。使用生物素化C86的下拉研究发现，在CRPC细胞中，Hsp 40与全长（FL-）AR、ARv 7和Hsp 70存在于多蛋白复合物中。用C86或变构热休克蛋白70（Hsp 70）抑制剂JG 98处理CRPC细胞导致FL-AR和ARv（包括ARv 7）的蛋白质快速失稳，同时FL-AR和ARv 7介导的转录活性降低。糖皮质激素受体（GR），其在CRPC的子集中的表达升高也导致雄激素非依赖性AR靶基因转录，也通过抑制Hsp 40或Hsp 70而不稳定。在体内，Hsp 40或Hsp 70抑制在22 Rv 1 CRPC异种移植模型中表现出单一药剂和组合活性。这些数据表明，除了Hsp 40和Hsp 70在FL-AR LBD重塑中的公认作用外，缺乏LBD的ARv仍然依赖于分子伴侣的稳定性和功能。我们的研究结果强调了靶向Hsp 40/Hsp 70伴侣轴治疗对标准抗雄激素治疗具有耐药性的前列腺癌的可行性和潜在益处。
Castration-resistant prostate cancer (CRPC) is characterized by reactivation of androgen receptor (AR) signaling in part by elevated expression of AR splice variants (ARv) including ARv7, a constitutively active, ligand binding domain (LBD)-deficient variant whose expression has been correlated with therapeutic resistance and poor prognosis. In a screen to identify small molecule dual inhibitors of both androgen-dependent and androgen-independent AR gene signatures, we identified the chalcone C86. Binding studies using purified proteins and CRPC cell lysates revealed C86 to interact with heat shock protein 40 (Hsp40). Pulldown studies using biotinylated-C86 found Hsp40 present in a multi-protein complex with full-length (FL-) AR, ARv7 and Hsp70 in CRPC cells. Treatment of CRPC cells with C86 or the allosteric heat shock protein 70 (Hsp70) inhibitor JG98 resulted in rapid protein destabilization of both FL-AR and ARv, including ARv7, concomitant with reduced FL-AR- and ARv7-mediated transcriptional activity. The glucocorticoid receptor (GR), whose elevated expression in a subset of CRPC also leads to androgen-independent AR target gene transcription, was also destabilized by inhibition of Hsp40 or Hsp70. In vivo, Hsp40 or Hsp70 inhibition demonstrated single agent and combinatorial activity in a 22Rv1 CRPC xenograft model. These data reveal that, in addition to recognized roles of Hsp40 and Hsp70 in FL-AR LBD remodeling, ARv lacking the LBD remain dependent on molecular chaperones for stability and function. Our findings highlight the feasibility and potential benefit of targeting the Hsp40/Hsp70 chaperone axis to treat prostate cancer that has become resistant to standard anti-androgen therapy.