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

癌胚蛋白在胎儿组织发育过程中以及在肿瘤细胞或肿瘤干细胞中高度表达。相反，在成人组织中，这些蛋白质消失或仅微弱表达。因此，这些结构是用于开发载体分子的理想靶标，所述载体分子在肿瘤组织中选择性地转运细胞毒性和免疫调节分子或放射性同位素而不影响正常组织。该项目的目标是1。使用噬菌体展示和/或核糖体展示针对重组靶蛋白或具有重组或组成型表达靶的细胞系，鉴定与癌胚蛋白5 T4、Cripto-1和ROR 1特异性结合的配体（肽或合成体）。2.体外和体内配体评价：配体放射性标记后，测量与重组蛋白、靶阳性和阴性细胞的结合以及内化和外排速率。在竞争实验中并使用等离子体表面共振光谱测定亲和力。将在人血清中测定稳定性。如果需要，通过氨基酸序列的随机化进行亲和力成熟。在荷瘤小鼠中通过生物分布实验和小动物SPECT和/或-PET成像进行放射性标记后，研究优化配体的药代动力学性质。

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.