抄録
Peptides, which consist of small numbers of amino acids covalently coupled with peptide bonds, are known to play functionally significant role through ligand-receptor interaction on cells to modulate various vital reactions, in spite of their small molecular weight and simple structure. With accordance of peptide synthesis technology, a peptide chip, which is a combinatorial solid support-bound synthetic peptide library on membrane, has brought more possibilities into peptide drug discovery researches. We here report, for the first time, the high-throughput peptide screening strategy using peptide chip. From the target functional protein Fas antigen ligand, which is well known as cell death or apoptotic signaling ligand, we found novel functional peptide domain of 5-mers by utilizing the peptide chip system associated with the cell assay method. The obtained peptide showed strong growth inhibition (68% inhibition compared with the control membrane without any binding peptide) to human leukemia Jurkat cell line in the cell viability assay. The growth inhibition effects of obtained peptide to other cell lines, including non-adhesive leukemia cells (A3, I9.2, K562) and adhesive cells (HeLa, 3T3), also revealed to be more than 95% in average. The effect was slightly weakened but showed significant inhibition when the peptide was synthesized as soluble form and applied to the cell viability assay. The advantageous feature of peptide chip screening system is the flexibility of synthesized peptide library, in which we can examine both length effects and amino acid substitution effects on one chip. So we succeeded to design novel 31 peptides with higher cell growth inhibitory effects by altering the original sequence. According to the results, the obtained novel peptides were considered to be candidates of peptide drug, which can induce cell death in cancer cells. Our cell assay system proposed here was also proved to be effective in such drug discovery and design.
