Heparin-Promoted Cellular Uptake of the Cell-Penetrating Glycosaminoglycan Binding Peptide, GBPECP, Depends on a Single Tryptophan

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• 作者：Li-Chun Hung ; Ingjye Jiang ; Chien-Jung Chen ; Jia-Yin Lu ; Yi-Fen Hsieh ; Ping-Hsieh Kuo ; Yi-Lin Hung ; Lily Hui-Ching Wang ; Margaret Dah-Tsyr Chang ; Shih-Che Sue
• 刊名：ACS Chemical Biology
• 出版年：2017
• 出版时间：February 17, 2017
• 年：2017
• 卷：12
• 期：2
• 页码：398-406
• 全文大小：577K
• ISSN：1554-8937

文摘

A 10-residue, glycosaminoglycan-binding peptide, GBP_ECP, derived from human eosinophil cationic protein has been recently designated as a potent cell-penetrating peptide. A model system containing peptide, glycan, and lipid was monitored by nuclear magnetic resonance (NMR) spectroscopy to determine the cell-penetrating mechanism. Heparin octasaccharide with dodecylphosphocholine (DPC) lipid micelle was titrated into the GBP_ECP solution. Our data revealed substantial roles for the charged residues Arg5 and Lys7 in recognizing heparin, whereas Arg3 had less effect. The aromatic residue Trp4 acted as an irreplaceable moiety for membrane insertion, as the replacement of Trp4 with Arg4 abolished cell penetration, although it significantly improved the heparin-binding ability. GBP_ECP bound either heparin or lipid in the presence or absence of the other ligand indicating that the peptide has two alternative binding sites: Trp4 is responsible for lipid insertion, and Arg5 and Lys7 are for GAG binding. We developed a molecular model showing that the two effects synergistically promote the penetration. The loss of either effect would abolish the penetration. GBP_ECP has been proven to enter cells through macropinocytosis. The GBP_ECP treatment inhibited A549 lung cancer cell migration and invasion, implying that the cellular microenvironment would be modulated by GBP_ECP internalization. The intracellular penetration of GBP_ECP leading to inhibition of epithelial cell migration and invasion depends on the presence of the tryptophan residue in its sequence compared with similar derivative peptides. Therefore, GBP_ECP shows substantial potential as a novel delivery therapeutic through rapid and effective internalization and interference with cell mobility.