多功能前列腺癌靶向纳米载药系统的构建及其化学-光热联合治疗作用

The chemo-photothermal combination therapy can provide a promising strategy to suppress the multidrug resistance in clinical treatment of metastatic castration resistant prostate cancer (mCRPC). The anticancer effects of HPMA copolymers and gold nanorods (GNRs) have been confirmed. However, there were few reports of the combination of HPMA copolymers and GNRs to achieve the targeting mCRPC therapy. In this present work, a novel multifunctional targeting drug delivery system, with GNRs and HPMA copolymer-docetaxel conjugates, was developed. Moreover, the HPMA copolymers were prepared with galectin-3 binding peptide (G3-C12) as the targeting moiety and pH-sensitive hydrozone bond. The chemotherapy and thermaltherapy of GP-(G3-C12)-DTX was forced on. The apoptotic/necrosis induction and the metastasis inhibition of GP-(G3-C12)-DTX against docetaxel-resistant prostate cancer cells (PC-3R) in vitro were studied via the methods of immunofluorescence assay and flow cytometry. The chemo-photothermal combination therapy of GP-(G3-C12)-DTX against mCRPC in vivo was investigated by magnetic resonance imaging and immunohistochemistry assay on the established lung metastasis nude mice model. It will provide a new breakthrough to explore targeting combination therapy of GP-(G3-C12)-DTX against metastatic prostate cancer.

化学-光热联合治疗为克服转移性去势抵抗型前列腺癌（mCRPC）临床化疗中的耐药性提供了新策略。HPMA聚合物药物接合物的抗癌活性和金纳米棒的热疗效应都已得到证明，但鲜有将二者结合靶向治疗mCRPC的报道。本课题拟以GNRs为核心，pH敏感型HPMA聚合物多西他赛接合物为修饰链，半乳凝素-3结合肽（G3-C12）为靶向分子，构建一种多功能前列腺癌靶向纳米载药系统（GP-(G3-C12)-DTX），并对其化疗热疗协同效应进行重点研究：采用免疫荧光、流式细胞术等方法研究GP-(G3-C12)-DTX对耐药型前列腺癌细胞PC-3R的凋亡/坏死诱导性和转移粘附抑制性；建立荷肺转移PC-3R异位瘤裸鼠模型，利用核磁共振成像、免疫组化技术，系统研究GP-(G3-C12)-DTX通过联合化疗和热疗对转移性前列腺癌的体内治疗作用。完成本课题为mCRPC靶向联合治疗作用机制研究提供了新的突破。

化学-光热联合治疗被视为癌症治疗的新策略，为了确保化疗药物和光热试剂能够被同时传输到肿瘤部位发挥多重协同功能，开发安全高效的传递系统势在必行。本研究首先构建了一种新型HPMA聚合物多烯紫杉醇接合物/金纳米棒共给药系统：合成HPMA聚合物多烯紫杉醇（DTX）接合物（pHPMA-DTX），提高DTX在生物体内的水溶性，降低其全身的毒副作用；采用晶种生长法制备出两种不同粒径的金纳米棒（GNRs），以光热转化效应为指标筛选工艺；初步考察共给药系统（pHPMA-DTX@GNRs）联合作用于前列腺癌的靶向性。结果表明，pHPMA-DTX@GNRs在NIR光照条件下，对PC-3细胞显示出比DTX和pHPMA-DTX更强的生长抑制活性、凋亡诱导能力和肿瘤蓄积速率。在此基础上，构建一种稳定的HPMA聚合物阿霉素接合物/金纳米棒化学耦合粒子（pHPMA-DOX@GNRs）：DOX通过pH敏感型腙键连接于半遥爪HPMA聚合物载体上，进而修饰在GNRs表面。结果表明， pHPMA-DOX@GNRs具有与GNRs相同的光热转化能力，在NIR条件下，加速DOX从聚合物上的降解，提高其细胞核内蓄积量，发挥出更强的PC-3细胞杀伤力和肿瘤生长抑制活性，表明该载药系统在化学-光热治疗前列腺癌的潜在优势。这些研究为临床治疗前列腺癌提供了新思路和新方法，也为联合治疗方案制定提供了理论依据。