Biological and chemical characterization of basic FGF-saporin mitotoxin.
Basic fibroblast growth factor (FGF) and saporin-6, a ribosome-inactivating protein, were chemically conjugated and characterized as a cytotoxin to cells expressing the basic FGF receptor. Structural and Western blot analysis of the conjugate showed that it contained saporin and basic FGF in equimolar amounts. The conjugate inhibited protein synthesis in a cell-free system and had potent cytotoxic activity (ID50 = 25pM) for cells expressing the basic FGF receptor. It is equipotent with basic FGF in radioreceptor assays and elutes from heparin Sepharose columns with 2M NaCl. The activity of the mitotoxin can be inhibited by competition with an excess of basic FGF but not nerve growth factor. The possibility that this mitotoxin can be used as an anti-angiogenic factor in paradigms that involve basic FGF is discussed.
Lappi
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DA
Department of Molecular and Cellular Growth Biology, Whittier Institute, La Jolla, CA 92037.
Martineau
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D
Baird
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D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003603:Cytotoxins / Q000302:isolation & purification / Q000633:toxicity*; D005346:Fibroblast Growth Factors / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity*; D000922:Immunotoxins; D007668:Kidney; D008938:Mitosis / Q000187:drug effects; D009699:N-Glycosyl Hydrolases; D010940:Plant Proteins / Q000302:isolation & purification / Q000633:toxicity*; D011500:Protein Synthesis Inhibitors / Q000302:isolation & purification / Q000633:toxicity; D011956:Receptors, Cell Surface / Q000187:drug effects; D017468:Receptors, Fibroblast Growth Factor; D054789:Ribosome Inactivating Proteins, Type 1; D012270:Ribosomes / Q000187:drug effects; D000076985:Saporins
D003603:Cytotoxins; D000922:Immunotoxins; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D011956:Receptors, Cell Surface; D017468:Receptors, Fibroblast Growth Factor; D054789:Ribosome Inactivating Proteins, Type 1; D005346:Fibroblast Growth Factors; D009699:N-Glycosyl Hydrolases; D000076985:Saporins