ENGINEERED INTELLIGENT MICELLE FOR TUMOR pH TARGETING

描述（由申请人提供）：本项目的目标是研究使用工程pH敏感性胶束治疗药物敏感性和多药耐药（MDR）癌症的可行性，这些癌症过度表达叶酸受体（FR）。我们的研究结果表明：1）阿霉素（DOX）胶束对敏感的MCF-7（乳腺癌）和A2780（卵巢癌）癌细胞及其MDR对应物具有相同的细胞毒性，2）胶束制剂对具有各种单细胞MDR机制的MDR细胞系具有细胞毒性（包括Pgp、MRP、LRP、拓扑异构酶II和bcl-2），3）制剂在小鼠模型中引起MDR乳腺和卵巢肿瘤异种移植物的肿瘤消退，4）聚合物细胞毒性和明显的全身毒性均未观察到。这些作用涉及三方面的机制：1）通过FR介导的内吞作用的主动内化，2）内体中DOX的pH触发释放和3）聚合物组分引起的内体膜破坏。这些连续事件避免ATP驱动的外排泵，允许高胞质DOX浓度并使药物螯合/胞吐最小化。这些联合作用压倒了MDR细胞提出的多因素防御机制。为了使我们更接近临床应用的长期目标，本更新申请旨在介绍聚合物和胶束生产的放大，第一部分中紫杉醇负载胶束的开发，两种胶束制剂的评价（多柔比星和紫杉醇）对抗耐药乳腺癌和卵巢癌肿瘤的临床前研究，以及使用临床上更相关的多药耐药细胞或组织模型进行制剂测试，同时考虑细胞内和肿瘤内药代动力学。公共卫生相关性：在当前资助期内测试的独特pH敏感性胶束/多柔比星制剂被发现在体外和体内动物模型中在肿瘤蓄积和杀死各种敏感和多药耐药肿瘤细胞方面有效。该研究通过动物研究沿着系统PK分析最终确定了最有效的制剂。所获得的结果有力地支持了临床前研究对未来转化研究的潜力。因此，这种竞争性的更新申请提出了开发聚合物和胶束的放大工艺以及新的胶束/紫杉醇制剂。紫杉醇是乳腺癌和卵巢癌的一线化疗药物，这是目前临床前研究的目标疾病。临床前研究将包括用于储存的粉末制剂的开发、粉末和溶液中载药胶束的稳定性研究、毒理学评价和功效研究。该研究还计划在细胞和组织水平上研究更多与临床环境和药代动力学分析相关的多药耐药模型。

DESCRIPTION (provided by applicant): The goal of this project is to investigate the feasibility of treating drug-sensitive and multidrug resistant (MDR) cancers, which overexpress folate receptors (FR) using engineered pH-sensitive micelles. Our results demonstrated that 1) doxorubicin (DOX) loaded micelles were equally cytotoxic to sensitive MCF-7 (breast) and A2780 (ovarian) cancer cells and their MDR counterparts , 2) micelle formulations were cytotoxic to MDR cell lines with various unicellular MDR mechanisms (including Pgp, MRP, LRP, topoisomerase II, and bcl-2), 3) the formulations caused tumor regression of both MDR breast and ovarian tumor xenografts in a mouse model, 4) polymer cytotoxicity and apparent systemic toxicity were not observed. The mechanisms involved in these effects are three-fold: 1) active internalization via FR-mediated endocytosis, 2) pH-triggered release of DOX in endosomes and 3) endosomal membrane disruption caused by the polymeric components. These sequential events avoid ATP-driven efflux pumps, allow high cytosolic DOX concentrations and minimize drug sequestration/exocytosis. These combined effects overwhelm multifactorial defense mechanisms presented by MDR cells. In an effort to bring us closer to our long-term goal of clinical application, this renewal application intends to present the scale-up of polymer and micelles production, the development of paclitaxel loaded micelles in Part I, the evaluation of two micelle formulations (doxorubicin and paclitaxel) against resistant breast cancer and ovarian cancer tumors for preclinical studies in Part II, and formulation testing using more clinically relevant multidrug resistant cell or tissue models while considering the intracellular and intratumoral pharmacokinetics. PUBLIC HEALTH RELEVANCE: Unique pH-sensitive micelle/doxorubicin formulations tested in current funding period were found to be effective in tumor accumulation and killing various sensitive and multidrug resistant tumor cells in vitro and in vivo animal models. The research finalized a most effective formulation from animal studies along with systemic PK analysis. The results obtained strongly support the potential of preclinical investigation for future translational study. This competing renewal application thus proposes to develop the scale-up processes of polymers and micelles as well as a new micelle/paclitaxel formulation. Paclitaxel is a frontline chemotherapeutic for breast and ovarian cancers, which are current target diseases of the preclinical investigation. The preclinical study will include development of a powder formulation for storage, stability studies of the drug-loaded micelles in powder and in solution, toxicological evaluation, and an efficacy study. The research also plans to investigate more multidrug resistant models relevant to clinical setting and pharmacokinetic analysis at cellular and tissue levels.