PSMA介导前列腺癌靶向与细胞内触发释药的核交联胶束递药系统的构建及其评价

Prostate cancer (PCa) is one of the most common forms of malignancy in men, and the incidence is rapidly increasing in our country. It is important to study the active targeting drug delivery system for PCa therapy. In the present work, we shall fabricate the core-crosslinked micellar drug delivery system which is capable of prostate cancer targeting mediated by prostate specific membrane antigen (PSMA) and reduction-sensitive triggered intracellular drug release. In the micelles, hydrophobic group lipoic acid is chosen which can form the reversibly crosslinkable micellar core. Glycol chitosan is selected as hydrophilic group, while PSMA-targeting peptide was applied as the targeting group in the micelles. And the drug-loaded core-crosslinked micelles will be prepared. We shall synthesize rational copolymers by controlling the contents of reaction groups, and optimize the formulations of core-crosslinked micelles. As a result, the particle size-controllable, well-stable and targeting micellar drug delivery system will be obtained, which can reduce the premature drug release in blood and effective drug release in tumor cells. The means and methods of interdisciplinary studies were used in this research. We shall apply fluorescent probe coumarin 6 as a model drug, and explore the action mechanism of coumarin 6-loaded micelles in the tumor cells. DiR (1,1′-dioctadecyltetramethyl indotricarbocyanine iodide) is selected as near-infrared fluorescent probe, and the biodistribution of DiR-loade micelles will be investigated in the tumor-bearing nude mice. The docetaxel-loaded micelles will be prepared and evaluated in vitro and in vivo. Moreover, the PCa-targeting activities of docetaxel-loaded micelles will be investigated. The biological safety of drug-loaded micelles will be preliminarily studied.Taken together, this novel kind of carrier and drug delivery system will provide new method and idea for the study on the preparations in PSMA-mediated targeted PCa therapy.

前列腺癌是最常见的男性恶性肿瘤之一，其发病率在我国呈快速上升的趋势。主动靶向给药系统应用于前列腺癌的治疗，具有重要的研究意义。本项目拟构建前列腺特异性膜抗原（PSMA）介导前列腺癌靶向、细胞内还原环境中触发释药的核交联胶束递药系统。该系统应用硫辛酸作为可逆交联的胶束内核基团，乙二醇壳聚糖作为亲水性基团，PSMA靶向多肽作为靶向头基，制备载药核交联胶束。通过聚合物载体参数的调控，优选核交联胶束的制备方法，以期获得粒径大小可控、稳定性佳、能减少药物在血液循环中提前释放、在肿瘤细胞内高效释药的靶向胶束递释系统。应用跨学科的研究手段与方法，阐明载荧光探针香豆素6胶束在细胞内的作用机制，探究载近红外荧光探针DiR胶束在荷瘤裸鼠体内的分布，系统研究载多西他赛胶束的递药性能和前列腺癌靶向作用；初步评价载药胶束的生物安全性。该新型载体和给药系统将为PSMA介导前列腺癌靶向制剂的研究提供新方法和新思路。

前列腺癌是最常见的男性恶性肿瘤之一，其发病率在我国呈快速上升的趋势。主动靶向给药系统应用于前列腺癌的治疗，具有重要的研究意义。本项目构建了前列腺特异性膜抗原（PSMA）介导前列腺癌靶向、细胞内还原环境中触发释药的核交联胶束递药系统。该系统应用乙二醇壳聚糖（GC）作为亲水性基团，硫辛酸（LA）作为疏水基团，合成得到两亲性硫辛酸-乙二醇壳聚糖（GC-LA）聚合物。利用前列腺癌靶向多肽（PCP）作为靶向物质，合成得到PCP修饰硫辛酸-乙二醇壳聚糖（PGC-LA）聚合物。通过使用不同分子量的乙二醇壳聚糖、LA和PCP不同取代度的聚合物，进行比较和优化聚合物分子结构参数和制备方法，制得粒径大小可控、体系稳定的普通胶束和核交联胶束。以抗肿瘤药物多西他赛（DTX）为模型药物、疏水性物质6-香豆素和DiR为荧光探针，利用乳化-溶剂蒸发法制备载药胶束，继而使用二硫苏糖醇作为交联剂制备核交联胶束。利用激光共聚焦显微镜（CLSM）和流式细胞仪研究载药胶束在肿瘤细胞中的入胞方式和作用机制。用四甲基氮唑蓝（MTT）法研究载药核交联胶束和载药非核交联胶束对LNCaP和PC-3细胞的毒性作用。通过体外溶血实验、小鼠体内的血液及血生化检验，初步评价空白胶束的生物安全性。建立荷LNCaP细胞（PSMA表达阳性）瘤裸鼠模型，研究载DTX胶束对荷LNCaP瘤裸鼠的组织分布和抗肿瘤作用效果。结果显示，新聚合物具有低毒、生物相容性好等特性。GC-LA聚合物中内核分子LA交联得到的核交联聚合物胶束具有还原响应性，体外释放药物比未交联胶束缓慢，在肿瘤内还原环境中能够触发释放药物。PCP多肽修饰的 PGC-LA胶束和PGC-LA核交联胶束能够明显增加在PSMA表达阳性LNCaP细胞的细胞摄取和毒性作用，以及达到荷瘤动物体内靶部位的高效输送。PGC-LA核交联胶束显著抑制荷LNCaP瘤裸鼠肿瘤的生长，可降低DTX的毒副作用。本项目完成论文7篇，其中SCI收录5篇，荣获江西省自然科学二等奖1项，参加国内学术会议12人次，完成培养硕士研究生3名。