Multimeric Ligands for Targeting of Melanoma

描述(由申请人提供)： 这项拟议工作的目标是开发平台靶向试剂，用于成像，并最终治疗转移性黑色素瘤。这些药物是针对细胞表面受体或表位组合的异多聚体配体。我们团队和其他人之前的工作表明，配体的同源多聚体通过一种称为合作亲和力的过程与其组成单体相比具有显著更高的亲和力。目前的研究将这一观察结果扩展到异源多聚体的使用。多聚体的组成将由DNA阵列和单体配体结合数据驱动，它们将不依赖于单个过表达的细胞表面蛋白，从而具有针对单个表位的药物的优势。与其他多功能试剂相比，它们具有优势，因为它们是通过聚合合成产生的，而且多聚体相对较小。有两个假设推动了这项工作。1)与单个单体相比，针对细胞表面蛋白组合的异构体配体具有更高的亲和力和明显的协同性。2)表达的细胞表面蛋白的组合可以唯一地定义单个细胞类型。拟议工作的两个目标遵循这两个假设。AIM 1将使用一个由四个明确定义的配体-受体组合组成的模型系统。该系统将用于确定最佳连接物间距和刚性、最佳单体单元亲和力、体外结合曲线和体内生物分布特性。目标2将筛选与转移性黑色素瘤相关的209种细胞表面蛋白的表达模式。这个屏幕将使用定制的DNA阵列，它将生成全面的数据集来识别潜在目标。这些数据将被用来比较已建立的和低传代原代培养的黑色素瘤细胞的表达模式，以及来自正常人体组织的mRNA文库。这些将通过RT-PCR和使用真正的激动剂的结合分析来证实。在AIM 2的末尾，这两个AIMS将在多聚体配体的设计中汇合，该多聚体配体将专门识别转移性黑色素瘤，最终用于这种晚期癌症的检测、诊断和治疗。

DESCRIPTION (provided by applicant): The goal of the proposed work is to develop platform targeting agents for imaging and, eventually, therapy of metastatic melanoma. These agents are heteromultimeric ligands directed against combinations of cell surface receptors or epitopes. Prior work by our team and others has shown that homomultimers of ligands bind with significantly higher affinity compared to their component monomers through a process known as cooperative affinity. The current research extends this observation to the use of heteromultimers. The composition of the multimers will be driven by DNA array and monomer ligand binding data, They will have advantages over agents directed against single epitopes by not relying on a single overexpressed cell surface protein. They will have advantages over other multifunctional agents in that they are produced via convergent synthesis and the multimer will be relatively small. Two hypotheses drive this work. 1) Heteromulfimeric ligands directed against combinations of cell surface proteins will bind with higher affinity and apparent cooperativity compared to individual monomers. 2) Combinations of expressed cell surface proteins can uniquely define individual cell types. The two aims of the proposed work follow these two hypotheses. Aim 1 will use a model system comprised of four well-defined ligand-receptor combinations. This system will be used to determine the optimum linker spacing and rigidity, the optimal avidity of the monomeric units, the in vitro binding curves and the in vivo biodistribution characteristic. Aim 2 will screen the expression patterns of 209 cell surface proteins associated with metastatic melanoma. This screen will use a custom DNA array, which will generate comprehensive data sets to identify potential targets. These data will be used to compare patterns of expression in melanoma cells from established and low passage primary cultures, to libraries ofmRNA from normal human tissues. These will be confirmed by RT-PCR, and by binding assays using bona fide agonists. At the end of Aim 2, the two aims will converge in the design of multimeric ligands that will specifically recognize metastatic melanoma for eventual use in detection, diagnosis and treatment of this terminal cancer.