Development of novel radiotracers targeting oncofetal proteins for the diagnosis and therapy of tumors

癌胎蛋白在胎儿组织发育过程中以及肿瘤细胞或肿瘤干细胞中高度表达。相反，在成人组织中，这些蛋白消失或仅弱表达。因此，这些结构是发展载体分子的理想靶标，这些载体分子可以在不影响正常组织的情况下选择性地在肿瘤组织中运输细胞毒性和免疫调节分子或放射性同位素。这个项目的目标是：1。利用噬菌体和/或核糖体展示技术，鉴定与癌胎蛋白5T4、Cripto-1和ROR1特异性结合的配体（多肽或sybodies），以对抗重组靶蛋白或重组或组成表达靶蛋白的细胞系。2. 配体的体外和体内评价：对配体进行放射性标记后，测量其与重组蛋白、靶阳性和阴性细胞的结合以及内化和外排速率。亲和力是用竞争实验和等离子体表面共振光谱测定的。稳定性将在人血清中测定。如果需要亲和成熟是通过随机化氨基酸序列完成的。通过生物分布实验和小动物SPECT和/或-PET成像，研究了优化配体在荷瘤小鼠体内的药代动力学特性。

Oncofetal proteins are highly expressed during the development of fetal tissues as well as in tumor cells or tumor stem cells. In contrast, in human adult tissues these proteins disappear or are only weakly expressed. Therefore, these structures are ideal targets for the development of carrier molecules which selectively transport cytotoxic and immunomodulatory molecules or also radioactive isotopes in tumor tissues without affecting normal tissues. The goals of this project are 1. identification of ligands (peptides or sybodies) with specific binding to the oncofetal proteins 5T4, Cripto-1 and ROR1 using Phage- and/or Ribosome-Display against recombinant target proteins or cell lines with recombinant or constitutive expression of the targets. 2. Evaluation of the ligands in vitro und in vivo: after radiolabelling of the ligands the binding to recombinant proteins, target-positive and -negative cells is measured as well as the internalisation and the efflux rate. Affinity is determined in competition experiments and using plasmon surface resonance spectroscopy. Stability will be measured in human serum. If needed an affinity maturation is done by randomisation of the amino acid sequences. The pharmacokinetic properties of the optimized ligands are investigated after radiolabelling in tumor-bearing mice by biodistribution experiments and small animal SPECT and/ or -PET Imaging.