Intelligent Polymeric Nanogel Technology Overcoming Drug Resistance in Ovarian Ca

这项建议的目的是探讨用智能病毒模拟纳米凝胶(VM-Nanogels)治疗卵巢上皮癌(OEC)的可行性。该VM纳米凝胶具有核壳型胶束状结构。核心是由pH敏感的聚合物块构建的，并装载了抗癌药物，如阿霉素(DOX)和紫杉醇(PTX)。VM-纳米凝胶的亲水性聚乙二醇壳与大分子(如白蛋白)部分交联，以维持其结构完整性。进一步用细胞穿透肽(如本方案中的TAT)修饰表面以使细胞进入活性区域，得到Vm(TAT)纳米凝胶。然后，VM(TAT)纳米凝胶的表面TAT在血管空间(PH)中被有效地屏蔽 7.4)通过反离子聚合物，如聚乙二醇b-聚磺酰胺，将最大限度地减少与正常健康组织的相互作用，但通过在肿瘤细胞外pH内脱皮暴露肿瘤细胞/组织。初步结果表明，负载DOX的VM(F)-纳米凝胶与叶酸(F)偶联，对敏感和多药耐药(MDR)癌细胞以及邻近完整的癌细胞具有高度的细胞毒作用。其主要功能有：1)叶酸受体介导的内吞作用，2)由胞体pH触发的DOX释放，3)通过Vm(F)-纳米凝胶的体积转换/渗透压破坏内膜，4)胞浆中最小的DOX释放，5)从死亡的癌细胞中逃逸并重新进入邻近细胞。Vm(F)-纳米凝胶最终被分解和消除。初步结果也证明了TAT的肿瘤特定pH脱除机制的可行性。 这种独特的方法将以最少量的选定药物和载体材料最大化治疗效果，并有望克服耐药性。Vm(Tat)纳米凝胶将避免生物系统中胶束稳定性的担忧，以及临床环境中包括叶酸受体在内的细胞表面标志物的异质性问题。本申请书概述了实现所述目标的四个具体目标。

The goal of this proposal is to investigate the feasibility of treating ovarian epithelial carcinoma (OEC) with intelligent virus-mimetic nanogels (VM-nanogels). The VM nanogel has a core-shell type micelle-like structure. The core is constructed with pH-sensitive polymer blocks and loaded with anticancer drugs such as doxorubicin (DOX) and paclitaxel (PTX). The hydrophilic poly(ethylene glycol) (PEG) shell of the VM-nanogel is partially cross-linked with macomolecules, such as albumin, to sustain its structural integrity. The surface is further modified with a cell penetrating peptide (such as TAT in this proposal) for active cell entry, yielding VM(TAT)-nanogel. The surface TAT of VM(TAT)-nanogel is then effectively shielded in the vascular space (pH 7.4) by counter ionic polymers, such as PEG-b-polysulfonamide, which will minimize interactions with normal healthy tissues but expose the tumor cells/tissue by deshielding within the tumor’s extracellular pH. Preliminary results demonstrate that DOX-loaded VM(F)-nanogels, conjugated with folate (F), are highly cytotoxic to both sensitive and multidrug resistant (MDR) cancer cells and migration/reentry into neighboring intact cancer cells. Major functions documented were: 1) folate receptor mediated endocytosis, 2) triggered release of DOX by endosomal pH, 3) endosomal membrane disruption by the volume transition/osmotic pressure of VM(F)-nanogels, 4) minimal release of DOX in the cytosol, and 5) escape from dead cancer cells and re-entry into neighboring cells. The VM(F)-nanogels are eventually disintegrated and eliminated. The preliminary results also demonstrate the feasibility of a tumor pH-specific deshielding mechanism for TAT. This unique approach will maximize therapeutic effects with minimal amounts of a selected drug and carrier materials and is expected to overcome drug resistance. The VM(TAT) nanogel will avoid concerns of micelle stability in biological systems and the heterogeneity issue of cell surface markers including folate receptor in the clinical setting. Four specific aims to achieve the stated goal are outlined in this application.