Targeting of Bladder Tumor Cells by Nanocarriers Bearing bacillus Calmette-Guerin

描述(申请人提供)：膀胱癌在男性中排名第四，在女性中排名第11。此外，70%的患者在手术治疗后病情复发。因此，开发针对这种病理的有效治疗方法是当务之急。该项目的长期目标是开发一种策略，使用来自治疗佐剂卡介苗(BCG)的纤维连接蛋白(FAP)将载药纳米载体靶向膀胱肿瘤细胞。事实上，我们最近发现，在类似膀胱的条件下，多价FAP-纳米载体对纤维连接蛋白：整合素复合体的微聚集诱导了人膀胱肿瘤细胞对纳米载体的摄取。在这里，我们将检验这一假设，即拓扑替康负载的FAP纳米载体的多价性和膜融合特性分别控制其摄取和细胞毒性。利用膀胱肿瘤细胞的培养和原位小鼠模型，我们将达到以下特定的目的：1.确定多价对FAP-纳米载体在膀胱肿瘤细胞内化的影响。2.检测不同融合特性的拓扑替康纳米载体对膀胱癌细胞的细胞毒作用。这个项目具有创新性，因为它使用了新型高效的靶向制剂，BCG的FAP，用于开发治疗膀胱癌的策略。此外，我们设计了一种促进膀胱肿瘤细胞内化FAP-纳米载体的方法。这种基于微聚簇的方法通过一个已知的动力学、转运途径和平均囊泡大小的机制来诱导FAP的摄取。此外，我们的方法比其他更传统的纳米载体策略(如使用RGD多肽进行靶向的策略)更具优势，因为如前所述，FAP在免疫个体中引起抗肿瘤免疫反应。此外，与RGD肽不同的是，FAP与纤维连接蛋白：整合素复合体结合，而不是针对低丰度的游离整合素或竞争纤维连接蛋白。此外，FAP不太可能对整合素信号起作用，因为它结合了先前存在的纤维连接蛋白：整合素复合体。事实上，我们的策略导致溶酶体靶向和降解可能的纤维连接蛋白：整合素信号复合体。

DESCRIPTION (provided by applicant): Bladder cancer is the fourth most common cancer in men and eleventh most common in women. In addition, seventy percent of patients suffer disease recurrence after surgical treatment. Therefore, the development of efficient therapeutics against this pathology is a high priority. The long-term objective of this project is to develop a strategy to target drug- loaded nanocarriers to bladder tumor cells using Fibronectin Attachment Protein (FAP) from the therapy adjuvant Bacillus Calmette-Guerin (BCG). Indeed, we recently showed that microclustering of Fibronectin:Integrin complexes by multivalent FAP-nanocarriers induced nanocarrier uptake by human bladder tumor cells under bladder-like conditions. Here, we will test the hypothesis that multivalency and membrane fusogenic properties of topotecan-loaded FAP-nanocarriers control their uptake and cytotoxicity, respectively. The following specific aims will be pursued using bladder tumor cells in culture and an orthotopic mouse model: 1. Determine the effect of multivalency on FAP-nanocarrier internalization by bladder tumor cells. 2. Determine in bladder tumor cells the cytotoxicity of topotecan-loaded FAP-nanocarriers with different fusogenic characteristics. This project is innovative because utilizes novel and efficient targeting agent, FAP from BCG, for the development of a therapeutic strategy against bladder cancer. Further, we devised a method for promoting the internalization of FAP-nanocarriers by bladder tumor cells. This microclustering-based approach induces FAP uptake through a mechanism with known kinetics, trafficking route and average vesicle-size. In addition, our approach is more advantageous than other more conventional nanocarrier strategies (like the ones using RGD peptides for targeting) because, as previously described, FAP elicits an anti-tumor immunoresponse in immunized individuals. Also, as opposed to RGD peptides, FAP binds to Fibronectin:Integrin complexes rather than targeting low abundance free Integrins or competing off Fibronectin. Further, FAP is not likely to contribute to Integrin-signaling as it binds pre-existing Fibronectin:Integrin complexes. In fact, our strategy leads to lysosomal targeting and degradation of putative Fibronectin:Integrin signaling complexes.