骨肉瘤细胞特异性结合短肽的筛选

目的：获得与骨肉瘤细胞株os-732特异结合的短肽，作为骨肉瘤靶向治疗的先导化合物。方法：以骨肉瘤细胞os-732为靶细胞，成骨细胞为吸附细胞对噬菌体12肽库进行差减筛选，用细胞ELISA、免疫组化鉴定阳性噬菌体克隆并测序。结果：经三轮筛选，从随机挑选的20个噬菌体克隆中得到9个特异性与骨肉瘤细胞os-732结合，而不与正常成骨细胞结合的阳性克隆。但其氨基酸序列无同源性。结论：得到多个序列不同的特异性结合骨肉瘤的噬菌体克隆，提示骨肉瘤细胞表面结构复杂，具多个骨肉瘤抗原表位。本实验获得的短肽具有一定的亲合力和肿瘤特异性，为针对不同位点的靶向药物设计提供了实验依据。

Screening of short peptides that bind specifically to osteosarcoma cells by phage-displayed peptide library]

OBJECTIVE: To obtain short peptides which bind specifically to osteosarcoma cells os-732 by means of screening from 12 peptide libraries. METHODS: Osteosarcoma cells os-732 were used as the target cells and osteoblasts as the absorber cells for subtraction biopanning from a 12-mer peptide phage-display library. After 3 rounds of screening, the positive phage clones were identified by cell enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, and the amino acid sequences were deduced by DNA sequencing. RESULTS: Nine positive phage clones screened out of 20 clones showed specific binding with osteosarcoma os-732, but no conserved motif was found in these peptides. CONCLUSION: The specific peptides screened from the phage library may be used as potential candidates as ligands for tumor-targeting therapy. The results also suggested that there are different epitopes on the surface of tumor cells.