肿瘤靶向共载前药胶束同步递送联合化疗药物协同抗肿瘤的研究

Efficient co-delivery of chemotherapeutic drugs to tumor cells is the key scientific issue in combination chemotherapy. Traditional nano drug delivery systems showed co-loading ability of combined drugs. However, the uncontrolled co-delivery in vivo showed some limitation of the traditional nano drug delivery systems in combination chemotherapy. In vitro cytotoxicity study have clearly demonstrated synergistic effect between doxorubicin (DOX) and dasatinib (DAS) on tumor cell inhibition in our preliminary study. A tumor microenvironment redox-sensitive POEG-b-pSSDAS micelle was developed for co-delivery of DOX and DAS into tumor cells and intracellular triggered drug co-release by combining with the targeted co-delivery and co-release strategies, for improving the synergistic anticancer therapy. Our preliminary work has proved that the prepared POEG-b-pSSDAS micelle has this function. The pharmacokinetics and tissue distribution characteristics will be studied for evaluating the synchronization effect on pharmacokinetic and distribution nbehavior of combined chemotherapeutic drugs, long circulation characteristics and tumor targeting ability of micelles. In vitro antitumor activity and in vivo tumor inhibition pharmacodynamic study will be investigated in detail for comprehensive evaluating the co-loading and tumor microenvironment redox-triggered drug co-released strategies of micellar system for enhancing the synergistic antitumor effect of drug combination. Drug co-delivered into tumor cells and intracellular co-released processes will be investigated for illustrating the synergistic antitumor mechanisms. We aim to provide a new targeted drug co-delivery and efficient intracellular co-release technology for the combination therapy of the chemotherapeutic drug and molecularly targeted drug.

实现联用药物同步共递送至肿瘤细胞是肿瘤联合化疗的关键科学问题。传统纳米制剂虽可实现联用药物共载，但药物体内同步递送不可控，严重影响其抗肿瘤协同作用。前期研究证实细胞毒药物阿霉素和分子靶向药物达沙替尼具有良好的联合抗肿瘤作用。本课题拟集成细胞毒化疗与分子靶向治疗，联合靶向共递释策略，构建肿瘤胞内触发释药式共载前药胶束，实现联用药物在肿瘤组织、细胞同步递送兼胞内高效共释药，以提高其抗肿瘤协同作用，前期研究已初步探明该胶束具有此功能。本课题将通过药动学及组织分布研究，评价胶束同步联用药物的体内药动学和组织分布作用，及其长循环和肿瘤组织靶向性；重点研究体内外抗肿瘤药效，综合评价胶束的共载药和靶向同步递送策略提高联用药物协同抗肿瘤的功效；考察胞内药物同步递送和触发共释药过程，阐明此胶束提高联用药物协同抗肿瘤机制。本课题以期为临床细胞毒与分子靶向药物联合化疗提供一项肿瘤靶向同步递送和胞内共释药新技术。

实现联用药物同步共递送至肿瘤细胞并有效释放是肿瘤联合化疗的关键科学问题。本课题针对细胞毒药物阿霉素（DOX）和分子靶向药物达沙替尼（DAS）的共递送、共释放问题，构建了胞内还原敏感并共载DOX的聚甲氧基聚乙二醇甲基丙烯酸酯-b-聚二硫达沙替尼前药胶束（DOX/POEG-b-PSSDas），实现联用药物在肿瘤组织、细胞同步递送兼胞内高效共释药，以提高其抗肿瘤协同作用。同时，合成碳碳键连接的非胞内还原敏感的POEG-b-PCCDas聚合物前药为对照。本课题通过还原敏感性考察和还原依赖性药物释放研究，阐明共载药胶束还原响应性释药的规律与机制；考察共载药胶束的组织分布及药动学行为，评价胶束同步联用药物的体内药动学和组织分布作用；重点研究共载药胶束体内外抗肿瘤药效，综合评价胶束的共载药和靶向同步递送策略提高联用药物协同抗肿瘤的功效。. 研究结果表明，DOX/POEG-b-PSSDas胶束在模拟生理环境和肿瘤细胞外液中均稳定，进入肿瘤细胞内触发还原敏感释药行为，可实现胶束携载药物在肿瘤细胞内高效共释放，达到协同抗肿功效。体外细胞增殖抑制及诱导凋亡实验结果表显示，DOX/POEG-b-PSSDas胶束在肿瘤细胞中具有最强的抗肿瘤活性，表明POEG-b-PSSDas中化学键合的DAS可有效释放于肿瘤细胞，联合DOX发挥协同抗肿瘤作用。体内药动学研究结果显示，与游离DOX溶液相比，共载药胶束明显延长DOX在血液中的循环时间。考察共载药胶束在肿瘤小鼠各组织中的分布情况发现，DOX/POEG-b-PSSDas胶束中的DOX在肿瘤组织中的蓄积量显著提高。以4T1.2乳腺癌小鼠为模型考察共载药胶束的抗肿瘤药效学。结果显示，DOX/POEG-b-PSSDas胶束组肿瘤体积最小，肿瘤细胞坏死面积最大，提示从前药载体裂解的DAS可与共递送的DOX产生协同抗肿瘤作用，并进一步证实了还原敏感型聚合物前药策略的有效性。. 综上所示，本课题通过分子、细胞和动物水平评价，阐明肿瘤靶向共载药胶束同步递送联合化疗药物DOX和DAS，提高其协同抗肿瘤的功效及机制，为肿瘤治疗提供一种细胞毒药物与分子靶向药物联合化疗新策略，也为肿瘤联合化疗纳米药物共递送平台的构建提供指导和借鉴。

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