Targeting Androgen Receptor Activation Function-1 with EPI to Overcome Resistance Mechanisms in Castration-Resistant Prostate Cancer.
Targeting Androgen Receptor Activation Function-1 with EPI to Overcome Resistance Mechanisms in Castration-Resistant Prostate Cancer.
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DOI：
10.1158/1078-0432.ccr-15-2901
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发表时间：
2016-09-01
期刊：
影响因子：
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通讯作者：
Sadar MD
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文献类型：
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作者：
Yang YC;Banuelos CA;Mawji NR;Wang J;Kato M;Haile S;McEwan IJ;Plymate S;Sadar MD
在去势抵抗性前列腺癌（CRPC）中，持续的雄激素受体（AR）转录活性在临床上是明显的。因此，AR仍然是CRPC可行的治疗靶点。目前所有的激素疗法都靶向AR的c端配体结合域（LBD）。通过使用EPI靶向AR激活功能-1 (AF-1)，在AR转激活所必需的n端结构域（NTD）中，我们评估了EPI克服几种临床相关AR相关耐药机制的能力。为了研究EPI对AR对SRC1-3和p300等过表达共激活因子的转录活性的影响，我们使用LNCaP细胞进行了荧光素酶报告基因检测。采用ar阴性COS-1细胞进行报告细胞试验，以检验聚谷氨酰胺束长度是否影响EPI的抑制作用。在表达AR- v7变异体的LNCaP95细胞中，研究了EPI对组成活性AR剪接变异体的影响。为了评估EPI对LNCaP95细胞增殖的影响，我们在体外进行了BrdU掺入实验，并在小鼠体内进行了异种移植研究。EPI有效地克服了一些潜在的异常AR活性的分子改变，包括过表达的共激活因子、AR功能获得突变和组成活性AR- v7。EPI对AR转录活性的抑制与聚谷氨酰胺束长度无关。重要的是，EPI显著抑制LNCaP95前列腺癌细胞的体外和体内增殖，LNCaP95是雄激素不依赖型和恩杂鲁胺耐药的。这些发现支持EPI作为一种有前景的治疗CRPC的药物，特别是针对由组成型活性AR剪接变异体驱动的肿瘤，这些变异体对lbd靶向药物具有耐药性。
Persistent androgen receptor (AR) transcriptional activity is clinically evident in castration-resistant prostate cancer (CRPC). Therefore, AR remains as a viable therapeutic target for CRPC. All current hormonal therapies target the C-terminus ligand-binding domain (LBD) of AR. By using EPI to target AR activation function-1 (AF-1), in the N-terminal domain (NTD) that is essential for AR transactivation, we evaluate the ability of EPI to overcome several clinically relevant AR-related mechanisms of resistance. To study the effect of EPI on AR transcriptional activity against overexpressed co-activators such as SRC1-3 and p300, luciferase reporter assays were performed using LNCaP cells. AR-negative COS-1 cells were employed for reporter assays to examine if the length of polyglutamine tract affects inhibition by EPI. The effect of EPI on constitutively active AR splice variants was studied in LNCaP95 cells, which express AR-V7 variant. To evaluate the effect of EPI on the proliferation of LNCaP95 cells, we performed in vitro BrdU incorporation assay and in vivo studies using xenografts in mice. EPI effectively overcame several molecular alterations underlying aberrant AR activity, including overexpressed coactivators, AR gain-of-function mutations, and constitutively active AR-V7. EPI inhibited AR transcriptional activity regardless of the length of polyglutamine tract. Importantly, EPI significantly inhibited the in vitro and in vivo proliferation of LNCaP95 prostate cancer cells, which are androgen-independent and enzalutamide-resistant. These findings support EPI as a promising therapeutic agent to treat CRPC, particularly against tumors driven by constitutively active AR splice variants that are resistant to LBD-targeting drugs.