Pooyan Shahriar, Qiu Bo, Chan Marion M, Fong Dunne, Sinko Patrick J, Leibowitz Michael J, Stein Stanley
Department of Chemistry, Rutgers University, Rutgers, Piscataway, New Jersey 08854, USA.
Bioconjug Chem. 2002 Mar-Apr;13(2):216-23. doi: 10.1021/bc0100657.
N-Formyl-methionyl peptides can specifically bind to surface receptors on phagocytic cells. A single copy of N-formyl-methionine-leucine-phenylalanine (fMLF) covalently linked to a poly(ethylene glycol)-based polymer displayed reduced binding avidity (K(d) = 190 nM) for differentiated HL-60 cells relative to free fMLF (K(d) = 28 nM). Increasing the number of fMLF residues (up to eight) attached to a single polymer results in enhanced avidity for these cells (K(d) = 0.18 nM), which appears to be independent of whether the polymer backbone is linear or branched. However, no conjugate showed enhanced ability to activate phagocytic cells, relative to the free peptide (EC(50) = 5 nM), as measured by transient stimulation of release of calcium ions from intracellular stores into the cytoplasm. A polymer bearing four fMLF and four digoxigenin residues showed specific enhancement in binding to differentiated HL-60 cells and mouse peritoneal macrophages in situ relative to a polymer lacking fMLF; no such enhancement was seen in binding to receptor-negative lymphocytic Jurkat cells. These results suggest that multiple fMLF residues linked to a drug-delivery polymer can be used to target appended drugs to phagocytic cells with relatively little toxicity due to cellular activation.
N-甲酰甲硫氨酰肽可特异性结合吞噬细胞表面的受体。与基于聚乙二醇的聚合物共价连接的单个N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸（fMLF）拷贝相对于游离fMLF（K(d)=28 nM）对分化的HL-60细胞的结合亲和力降低（K(d)=190 nM）。增加连接到单个聚合物上的fMLF残基数量（最多八个）会导致对这些细胞的亲和力增强（K(d)=0.18 nM），这似乎与聚合物主链是线性还是分支无关。然而，相对于游离肽（EC(50)=5 nM），通过短暂刺激钙离子从细胞内储存库释放到细胞质中进行测量，没有共轭物显示出激活吞噬细胞的能力增强。与缺乏fMLF的聚合物相比，带有四个fMLF和四个地高辛配基残基的聚合物在原位与分化的HL-60细胞和小鼠腹腔巨噬细胞的结合中显示出特异性增强；在与受体阴性的淋巴细胞Jurkat细胞的结合中未观察到这种增强。这些结果表明，与药物递送聚合物连接多个fMLF残基可用于将附加药物靶向吞噬细胞，由于细胞激活，其毒性相对较小。
