ENGINEERED INTELLIGENT MICELLE FOR TUMOR pH TARGETING

描述（由申请人提供）：该项目的目标是研究利用工程ph敏感胶束治疗过表达叶酸受体（FR）的药物敏感和多药耐药（MDR）癌症的可行性。我们的研究结果表明，1)负载多柔比霉素（DOX）胶束对敏感的MCF-7（乳腺癌）和A2780（卵巢癌）细胞及其耐多药对应物具有相同的细胞毒性，2)胶束配方对具有多种单细胞耐多药机制的MDR细胞系（包括Pgp， MRP， LRP，拓扑异构酶II和bcl-2）具有细胞毒性，3)该配方在小鼠模型中引起MDR乳腺和卵巢肿瘤异种移植的肿瘤消退。4)未观察到聚合物的细胞毒性和明显的全身毒性。这些作用涉及的机制有三个方面：1)通过fr介导的内吞作用主动内化，2)ph触发的内体DOX释放和3)聚合物成分引起的内体膜破坏。这些连续的事件避免了atp驱动的外排泵，允许高细胞质DOX浓度和最小化药物隔离/胞外作用。这些综合效应压倒了MDR细胞呈现的多因子防御机制。为了使我们更接近临床应用的长期目标，本更新申请打算在第一部分中介绍聚合物和胶束生产的规模扩大，紫杉醇负载胶束的开发，在第二部分中评估两种胶束配方（阿霉素和紫杉醇）用于耐药乳腺癌和卵巢癌肿瘤的临床前研究。在考虑细胞内和肿瘤内药代动力学的同时，使用更多临床相关的多药耐药细胞或组织模型进行配方测试。

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.