Cancer Therapeutics that Anchor Proteins to Membranes

描述（由申请人提供）：耐多药（MDR）癌症仍然是治愈性癌症化疗的主要障碍。MDR癌细胞与典型肿瘤细胞的不同之处是，它显著上调了几种因子的产生，包括药物转运蛋白p -糖蛋白、胆固醇结合蛋白小窝蛋白和细胞膜脂筏微域成分。这些筏结构域富含胆固醇和鞘脂，在信号转导过程中起关键作用。耐多药癌症的质膜的独特组成可能使选择性化疗针对这些癌症。在上一个资助周期，新的小分子被合成，包括胆固醇胺共价连接到蛋白质配体，如生物素。这些化合物结合了癌细胞质膜上的脂筏。用合成生物素-胆固醇胺配体（配体#1）和蛋白质链亲和素（SA）治疗癌细胞，有效地将SA靶向到脂筏上，导致网格蛋白介导的这种蛋白质-配体复合物的快速内吞。这种新系统模拟霍乱毒素对细胞的渗透，霍乱毒素结合脂筏中的神经节苷脂GM1。这个项目是基于一个假设，即配体#1将调节癌细胞细胞系中与内核体激活毒素柔红霉素和外毒素相关的SA的内吞作用。由于配体#1与脂筏结合，因此将在体外和体内小鼠癌症模型中研究sa连接毒素对富含脂筏的MDR癌细胞的选择性递送。配体#1在增强Satoxins与神经肽Y融合的内吞作用方面的有效性也将被评估，神经肽Y靶向神经母细胞瘤细胞上的特定受体。这种通过靶向小分子脂筏增强表面受体内吞作用的新方法可以解决非内化肿瘤抗原免疫治疗的主要问题。配体调节的SA递送到抗原呈递细胞（APCs）将刺激免疫反应的假设也将被验证。新的免疫刺激剂将通过将SA与卵清蛋白抗原融合，用配体#1调节APCs的内吞作用，并分析t细胞活化来研究。这种方法可以在分子水平上控制免疫刺激，并为疫苗开发提供新的工具。通过配体#1向质膜募集细胞内亲和素融合蛋白也将被研究，以有条件地调节细胞的生长和死亡

DESCRIPTION (provided by applicant): Multidrug resistant (MDR) cancer remains the primary impediment to curative cancer chemotherapy. MDR cancer cells differ from typical tumor cells by dramatically upregulating production of several factors including the drug transporter P-glycoprotein, the cholesterol binding protein caveolin, and components of lipid raft microdomains of cellular plasma membranes. These raft domains are enriched in cholesterol and sphingolipids and play key roles in signal transduction processes. The distinct composition of plasma membranes of MDR cancers may enable selective chemotherapy targeting these cancers. During the last grant cycle, novel small molecules were synthesized that comprise cholesterylamine covalently linked to protein ligands such as biotin. These compounds bind lipid rafts in plasma membranes of cancer cells.Treatment of cancer cell lines with a synthetic biotin-cholesterylamine ligand (ligand #1) and the protein Streptavidin (SA) efficiently targets SA to lipid rafts, resulting in rapid clathrin-mediated endocytosis of this protein-ligand complex. This novel system mimics penetration of cells by Cholera toxin, which binds ganglioside GM1 in lipid rafts. This project is based on the hypothesis that ligand #1 will regulate endocytosis of SA linked to endosome-activated toxins daunorubicin and exotoxin in cancer cell lines. Since ligand #1 binds lipid rafts, selective delivery of SA-linked toxins to lipid raft-rich MDR cancer cells will be investigated in vitro and in vivo in murine cancer models. The effectiveness of ligand #1 at enhancing endocytosis of Satoxins fused to neuropeptide Y, which targets specific receptors on neuroblastoma cells, will also be evaluated. This novel approach directed at enhancing endocytosis of surface receptors by targeting to lipid rafts with small molecules could address the major problem in immunotherapy of non-internalized tumor antigens. The hypothesis that ligand-regulated delivery of SA to antigen presenting cells (APCs) will stimulate immune responses will also be tested. Novel immunostimulants will be investigated by fusing SA to the ovalbumin antigen, regulating endocytosis in APCs with ligand #1, and analyzing T-cell activation. This approach could control immunostimulation at the molecular level and yield novel tools for vaccine development. Recruitment of intracellular avidin fusion proteins to plasma membranes by ligand #1 will also be studied in an effort to conditionally regulate cellular growth and death