CG3适体介导的肿瘤环境响应性纳米胶束载miR-26a/恩扎鲁胺靶向去势抵抗性前列腺癌的作用机制研究

Drug resistance and target deficiency are the challenges in Castrate-Resistant Prostate Cancer (CRPC) treatment. Enzalutamide is a new androgen receptor inhibitor for CRPC consistent with resistance to therapy. One of the reasons is the upgradation of Wnt5a and activation of noncanonical Wnt signaling pathway, further attenuating the anti-proliferative effect of AR inhibitor. It was reported that miR-26a can inhibit prostate cancer progression by down-regulation of Wnt5a as well as regulation of other signaling pathways. Here we have built CG3-PEOz-d-R11CPss micelles for co-delivery of miR-26a and enzalutamide to CRPC cells. This long circulating and tumor-environment responsive nano-system has a function of prostate cancer cells member penetration as well as targeting to prostate cancer specific antigen PCA3 using CG3 aptamer. We hypothesis that miR-26a could prevent the resistance of enzalutamide as well as inhibit the prostate cancer synergistically. For this purpose, the triggering release characteristics of drug in tumor-environment, the transport and degradation mechanism of micelles in cells, in vivo distribution, in vitro/in vivo efficacy, biocompability as well as molecular mechanism will be investigated.

药物抵抗与缺乏靶向性是去势抵抗性前列腺癌（CRPC）的治疗难点。恩扎鲁胺是一种治疗CRPC的新型雄激素受体抑制剂，但一段时间用药后出现耐药现象，其原因是Wnt5a在前列腺癌细胞中的高表达减弱了雄激素抑制剂的抗肿瘤效果。研究表明miR-26a可通过下调Wnt5a抑制非经典途径Wnt信号通路，并作用于多个靶基因来阻断前列腺癌的发生发展。本课题以靶向前列腺癌PCA3抗原的CG3适体为靶头，首次构建具有前列腺特异靶向性、前列腺癌特异穿膜能力、长循环和肿瘤环境氧化还原和pH双响应性的多功能纳米胶束CG3-PEOz-d-R11CPss，共载miR-26a和恩扎鲁胺，输送至CRPC细胞，以防止恩扎鲁胺耐药、并从抑制雄激素和基因层面协同治疗CRPC。本研究将考察纳米胶束入胞及胞内转运机制、胞内触发释药特性、体内分布特征、体内外药效、安全性及分子机制，探讨验证miR-26a和恩扎鲁胺协同治疗CRPC的机理。

药物抵抗与缺乏靶向性是CRPC的治疗难点, 恩扎鲁胺作为治疗CRPC的新型雄激素受体抑制剂，在患者使用一定时间后出现耐药。我们研究发现，1）miR-26a在恩扎鲁胺耐药和敏感的CRPC细胞中表达有显著差异，表现为在耐药细胞和组织中缺失，提示miR-26a与恩扎鲁胺耐药有密切联系。进一步，我们证实了miR-26a不仅通过非经典Wnt5A信号通路抑制雄激素受体AR和AR-V7的表达，还通过阻断经典通路β-catenin的积累进而抑制靶基因c-Myc的转录，减少恩扎鲁胺耐药; 2) 此外，我们还发现miR-26a可抑制EMT来控制前列腺癌的迁移和侵袭, 并下调靶基因EZH2、Lin28B和Zcchc11的表达，起到协同抑制CRPC的作用。3) 我们构建了载药量高、转染效率高和安全性好的阳离子多肽纳米递送系统，该纳米粒可将miR-26a和恩扎鲁胺精准靶向至CRPC细胞，一方面，miR-26a提高了恩扎鲁胺在耐药细胞上的敏感性，两药联合使用协同增加药效；另一方面，药物在纳米靶向作用下在肿瘤部位蓄积，安全性显著增加。总之，本课题发现了miR-26a可抑制恩扎鲁胺耐药，并具有与恩扎鲁胺协同治疗CRPC的效果，我们考察其抑制耐药的机制，验证两药协同治疗CRPC的机理，证明了该递送系统的前列腺癌特异靶向性和良好安全性，为CRPC的内分泌联合治疗提供一种有效的治疗策略。本项目在Theranostics、British J Pharmcol、J Nanobiotech等杂志发表相关SCI论文10篇，一项专利。