TR4介导去势抵抗性前列腺癌对恩杂鲁胺耐药的机理研究

The Castration-Resistant Prostate Cancer (CRPC) remains an incurable disease which typically resulted in prostate cancer specific deaths. The paradigm of CRPC treatment has been dramatically changed over the past decade since the development of novel agents demonstrating efficacy in CRPC setting. These agents included enzalutamide, a novel antiandrogen, which could improve the patients’ progression-free survival and overall survival. However, there would be 20% to 40% of patients in CRPC setting who were resistant to enzalutamide, and the exact mechanism is still not fully understood. TR4 as a transcriptional regulator that belongs to the nuclear receptor superfamily, has been demonstrated to be correlated with the PCa cells’ radio-sensitivity and chemo-resistance. In previous studies, we have found that TR4 was associated with the PCa cells’ resistant to enzalutamide in certain cell lines, and it is postulated that TR4 might mediate the enzalutamide-resistance through the TR4/MALAT1/AR-V7 pathway. Therefore, we would use both the in vitro and in vivo studies to investigate the mechanism of the TR4 mediated PCa cells’ enzalutamide-resistance. This study could illustrate the mechanism of the PCa cells’ resistant to enzalutamide, and it would support that targeting TR4 could convert the PCa cells’ resistant to enzalutamide. Furthermore, the application of this study may bring a promoted therapeutic outcome to battle CRPC in future.

去势抵抗性前列腺癌目前尚缺乏有效的治疗手段，患者预后多不佳。恩杂鲁胺是目前为数不多可以明显改善CRPC患者预后的新药之一。然而约20%～40%的患者会对恩杂鲁胺耐药，造成治疗失败。因此，阐明CRPC对恩杂鲁胺产生耐药的机制是目前研究的热点。TR4已被证明在前列腺癌进展和放化疗抵抗中发挥重要作用。前期研究发现TR4与前列腺癌恩杂鲁胺耐药相关；TR4可能通过调控MALAT1来影响AR-V7的生成，从而改变前列腺癌对恩杂鲁胺的敏感性。本课题拟采用ChIP、荧光素酶双报告、RNA免疫共沉淀等技术来证实TR4/MALAT1/AR-V7通路的调控关系；利用裸鼠荷瘤实验来验证靶向TR4对恩杂鲁胺耐药的逆转作用；从体内和体外实验多角度阐明TR4调控MALAT1、上调AR-V7的表达、从而介导恩杂鲁胺耐药的机制；探索靶向TR4逆转恩杂鲁胺耐药的可能性；为临床解决CRPC恩杂鲁胺耐药的问题提供新的思路和方法。

去势抵抗性前列腺癌（CRPC）患者的预后不佳。恩杂鲁胺（MDV3100）是新一代的选择性雄激素受体（AR）拮抗剂，可以明显改善CRPC患者疾病进展和生存率。但有20%～40%的患者对恩杂鲁胺呈现原发性耐药。TR4可在PCa的进展和转移以及PCa患者的放化疗抵抗中发挥重要的作用。前期研究发现TR4与PCa的恩杂鲁胺耐药可能相关。. 本研究中，我们建立了稳定转染的TR4差异表达PCa细胞株和恩杂鲁胺耐药的PCa细胞株，构建了稳定转染的TR4基因敲低的C4-2 MDV-R耐药细胞株。检测了TR4差异表达后对PCa细胞恩杂鲁胺敏感性的影响，研究了恩杂鲁胺耐药的PCa细胞的TR4表达差异。通过体外实验验证靶向TR4从而逆转耐药PCa细胞对恩杂鲁胺的敏感性。我们利用ChIP实验和荧光素酶双报告系统检测，证明TR4可在转录水平直接调控MALAT1。建立了MALAT1过表达和MALAT1敲低的恩杂鲁胺耐药PCa细胞株，明确MALAT1对AR-V7的生成具有调节作用。我们采用解救实验和反解救实验进一步研究了TR4/MALAT1/AR-V7通路之间调控关系。. 通过本研究，我们初步阐明TR4导致PCa对恩杂鲁胺耐药的具体分子机制：明确TR4是通过在转录水平上直接调控MALAT1、利用MALAT1影响AR转录产物的剪切、从而上调AR剪接变异体AR-V7的表达、导致PCa对恩杂鲁胺产生耐药。探索了靶向TR4/MALAT1/AR-V7通路逆转PCa对恩杂鲁胺耐药的可能性，为临床上CRPC患者的治疗提供新的思路和方法。