Multivalent ligands for targeting invasive tumor cells

描述（由申请人提供）：聚合物科学、生物工程和基因组学领域的最新进展为开发特定癌症疗法的协同和战略方法提供了令人兴奋的机会。聚集在这里的多学科研究人员团队将每个领域的重要贡献汇集在一起，以创建一种新的和潜在的强大的通用策略，用于将治疗分子靶向过表达两种细胞表面受体的细胞。测试的假设是多价配体（许多配体结合到一种聚合物上）可以将该构建体对靶细胞类型的特异性增加至少一个数量级，同时将未结合配体的所需浓度降低至少一个数量级。此外，假设如果配体类型之一与整联蛋白结合，它将降低细胞粘附强度，从而阻止肿瘤细胞迁移。结合基因组测试以确定哪些细胞表面受体在特定病理细胞类型中高度表达，这种双配体类型策略具有靶向几乎任何细胞病理的潜力，其中至少两种细胞表面受体的表达上调;本研究的具体目的旨在证明基于该方法的模型系统的原理证明。通过整体基因表达数据确定的受体靶标的配体将被合成或从重组生产中分离。这些将结合到具有侧链的共聚物上，每个侧链含有两个化学反应性基团中的一个。将开发这些多价配体与细胞结合的数学模型，并通过与体外亲和力和特异性实验进行比较来测试模型的准确性。该模型的预测将通过系统地改变聚合物构建体上每种配体类型的数量来实现，以优化癌细胞与正常脑细胞的特异性。最后，在体外细胞培养细胞粘附，细胞迁移和凋亡的测定将确定这些结构的治疗潜力。

DESCRIPTION (provided by applicant): Recent advances in the fields of polymer science, bioengineering, and genomics present an exciting opportunity for a synergistic and strategic approach to developing specific cancer therapies. The multi-disciplinary team of investigators assembled here brings the important contributions from each field together to create a novel and potentially powerful general strategy for targeting therapeutic molecules to cells overexpressing two cell surface receptors. The hypothesis tested is that multivalent ligands (many ligands bound to one polymer) can increase specificity of that construct for a target cell type by at least one order-of magnitude, while decreasing the required concentration of unbound ligand by at least one order-of magnitude. Further, it is hypothesized that, if one of the ligand types binds to an integrin, it will decrease cell adhesion strength thus preventing tumor cell migration. Combined with genomic testing to determine which cell surface receptors are highly expressed in specific pathological cell types, this two-ligand type strategy has potential to target almost any cellular pathology in which the expression of at least two cell surface receptors is up-regulated; and the specific aims in this study are intended to demonstrate proof-of principle for a model system based on this approach. Ligands for a receptor target determined by global gene expression data will be synthesized or isolated from recombinant production. These will be bound in combination to a co-polymer with side chains each containing one of two chemically reactive groups. A mathematical model of these multivalent ligands binding to cells will be developed, and the accuracy of the model will be tested by comparing to in vitro affinity and specificity experiments. The model's predictions will be implemented by systematically varying the number of each ligand type on the polymer construct to optimize specificity for cancer cells versus normal brain cells. Finally, in vitro cell culture assays for cell adhesion, cell migration, and apoptosis will determine the therapeutic potential of these constructs.