Lappi D A, Maher P A, Martineau D, Baird A
Department of Molecular and Cellular Growth Biology, Whittier Institute for Diabetes and Endocrinology, La Jolla, California 92037.
J Cell Physiol. 1991 Apr;147(1):17-26. doi: 10.1002/jcp.1041470104.
We have confirmed the hypothesis that a mitotoxin resulting from the conjugation of basic fibroblast growth factor and saporin exerts its cytotoxic effect through specific interaction with the basic fibroblast growth factor (FGF) receptor. Accordingly, the mitotoxin stimulates tyrosine phosphorylation of the 90 kD substrate that characterizes the initial cellular response to basic FGF. Cross-linking experiments show that radio-labeled basic fibroblast growth factor-saporin (FGF-SAP) binds to the receptor. Suramin, an inhibitor of growth factor receptor binding, inhibits the cytotoxicity of basic FGF-SAP. In a study of 4 different cell types, there is a decrease in the ED50 of the mitotoxin as the receptor number per cell increases. We have verified the cytotoxicity of the mitotoxin in 3 different assay systems. As expected, it is effective in the inhibition of protein synthesis and DNA synthesis, as well as of cell count. Binding of basic FGF-SAP which will result in cytotoxicity occurs very rapidly; 5 minutes of incubation of 10 nM basic FGF-SAP with cells results in 80% inhibition of cell count. The in vitro data indicate that the basic FGF-SAP is a receptor specific and potent suicide antagonist of basic FGF. Its potential as an anti-FGF for therapeutic and research uses in vivo is discussed.
碱性成纤维细胞生长因子与皂草毒素结合产生的一种线粒体毒素，通过与碱性成纤维细胞生长因子（FGF）受体的特异性相互作用发挥其细胞毒性作用。因此，这种线粒体毒素刺激90kD底物的酪氨酸磷酸化，这是细胞对碱性FGF初始反应的特征。交联实验表明，放射性标记的碱性成纤维细胞生长因子-皂草毒素（FGF-SAP）与该受体结合。生长因子受体结合抑制剂苏拉明可抑制碱性FGF-SAP的细胞毒性。在对4种不同细胞类型的研究中，随着每个细胞受体数量的增加，线粒体毒素的半数有效剂量（ED50）降低。我们已经在3种不同的检测系统中验证了这种线粒体毒素的细胞毒性。正如预期的那样，它在抑制蛋白质合成、DNA合成以及细胞计数方面是有效的。会导致细胞毒性的碱性FGF-SAP的结合非常迅速；10 nM碱性FGF-SAP与细胞孵育5分钟会导致80%的细胞计数抑制。体外数据表明，碱性FGF-SAP是一种受体特异性且强效的碱性FGF自杀拮抗剂。文中讨论了其作为抗FGF在体内治疗和研究用途方面的潜力。
