Cytotoxic activity of recombinant bFGF-rViscumin fusion proteins.
A fusion protein (bFGF-rMLA), containing the mitogen basic fibroblast growth factor (bFGF) and the cytotoxic component of rViscumin (recombinant mistletoe lectin), the enzymatic A-chain (rMLA), was expressed in Escherichia coli, purified, and functionally characterized. bFGF-rMLA is cytotoxic for mouse B16 melanoma cells expressing the FGF receptor with an IC(50) value of approximately 1 nM. rMLA shows no significant effect on the viability of the B16 cells up to a concentration of 141 nM. Additionally, bFGF-rMLA was associated with the rViscumin B-chain (rMLB) in an in vitro folding procedure. The IC(50) value of bFGF-rMLA/rMLB to B16 cells in the presence of lactose-to block rMLB lectin activity-was 134 pM. Thus, it was possible to enhance the efficacy of a rViscumin A-chain mitotoxin through addition of rMLB. We conclude that rViscumin fusion proteins may be generally applicable for the receptor-specific inactivation of target cells and point out their potential in drug development.
Schmidt
A
A
BRAIN Aktiengesellschaft, Zwingenberg, 64673, Germany.
Möckel
B
B
Eck
J
J
Langer
M
M
Gauert
M
M
Zinke
H
H
D000818:Animals; D016923:Cell Death / Q000187:drug effects; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D037102:Lectins / Q000737:chemistry; D008546:Melanoma, Experimental; D051379:Mice; D009841:Oligonucleotides / Q000378:metabolism; D028321:Plant Preparations; D010940:Plant Proteins; D010957:Plasmids / Q000378:metabolism; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D054790:Ribosome Inactivating Proteins, Type 2; D013997:Time Factors; D014118:Toxins, Biological / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D037102:Lectins; D009841:Oligonucleotides; D028321:Plant Preparations; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; D016222:Fibroblast Growth Factor 2