Cancer Therapeutics that Anchor Proteins to Membranes

多药耐药（MDR）癌症仍然是治愈性癌症化疗的主要障碍。MDR 癌细胞与典型的肿瘤细胞的不同之处在于显著上调几种因子的产生，包括 药物转运蛋白P-糖蛋白、胆固醇结合蛋白小窝蛋白和脂筏组分 细胞质膜的微区。这些筏结构域富含胆固醇， 鞘脂，并在信号转导过程中发挥关键作用。血浆的独特成分 MDR癌细胞的细胞膜可以使选择性化疗靶向这些癌症。在过去 在Grant循环中，合成了新的小分子，其包含共价连接至 蛋白质配体如生物素。这些化合物结合癌细胞质膜中的脂筏。 用合成的生物素-胆固醇胺配体（配体#1）和蛋白质治疗癌细胞系 链霉亲和素（SA）有效地将SA靶向脂筏，导致这种脂筏的快速网格蛋白介导的内吞。 蛋白质-配体复合物这种新的系统模拟霍乱毒素对细胞的渗透， 脂筏中的神经节苷脂GM 1。该项目基于配体#1将调节内吞作用的假设 SA与癌细胞系中的内体激活毒素柔红霉素和外毒素连接。由于配体#1 结合脂筏，SA连接的毒素向富含脂筏的MDR癌细胞的选择性递送将在 在小鼠癌症模型中的体外和体内。配体#1在增强SA-1的内吞作用方面的有效性 与神经肽Y融合的毒素，其靶向神经母细胞瘤细胞上的特异性受体， 评估。这种新的方法通过靶向脂质， 小分子筏可以解决非内化肿瘤免疫治疗的主要问题 抗原假设配体调节SA向抗原呈递细胞（APC）的递送将 还将测试刺激免疫反应。新型免疫刺激剂将通过将SA融合到 卵清蛋白抗原，用配体#1调节APC中的内吞作用，并分析T细胞活化。这 这种方法可以在分子水平上控制免疫刺激，并产生新的疫苗工具。 发展通过配体#1将细胞内抗生物素蛋白融合蛋白募集至质膜也将 在有条件地调节细胞生长和死亡的努力中进行研究。

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 SA- toxins 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.