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Cytosolic beta-glycosidases for activation of glycoside prodrugs of daunorubicin.
- Source :
-
Biochemical pharmacology [Biochem Pharmacol] 2003 Jun 01; Vol. 65 (11), pp. 1875-81. - Publication Year :
- 2003
-
Abstract
- Human cytosolic beta-glycosidase is a small monomeric enzyme that is active under physiological conditions, which might be ideal for enzyme-prodrug therapy. We have previously reported the synthesis of a galactoside (DNR-GlA3) and a glucoside (DNR-GsA3) prodrug of daunorubicin. In the present study, we established that cellular uptake of DNR-GlA3 and DNR-GsA3 was low in contrast to that of daunorubicin. Recombinant human beta-glycosidase converted both prodrugs to daunorubicin as shown by liquid chromatography. The kinetics of the conversion of DNR-GlA3 and DNR-GsA3 by human beta-glycosidase, however, was unfavorable as the K(m) values were, respectively, 3- and 6-fold higher than those of another mammalian beta-glycosidase of bovine origin. The V(max) values were, respectively, 3.3 and 8.5nmol/hr/mg as compared to 158.3 and 147.8nmol/hr/mg of the bovine enzyme. Treatment of OVCAR-3 cells with human beta-glycosidase (0.5U/mL) and 0.5 microM DNR-GlA3 or DNR-GsA3 resulted in, respectively, 86 and 81% cell growth inhibition, while the prodrugs alone inhibited growth to only 19 and 1%. Treatment of cells with the bovine enzyme and the prodrugs inhibited cell growth more efficiently. We conclude that the endogenous intracellular beta-glycosidase is not available for extracellular prodrug activation. Thus, the incorporation of the enzyme in enzyme-prodrug therapy might be an elegant approach to achieve tumor-specific prodrug conversion. The efficiency of glycoside prodrug conversion might be improved by design of a prodrug that is more readily activated by human beta-glycosidase or by evolution of the enzyme into a mutant form that displays high activity towards these prodrugs.
- Subjects :
- Animals
Antibiotics, Antineoplastic metabolism
Biotransformation
CHO Cells
COS Cells
Cell Division drug effects
Cricetinae
Cytosol enzymology
Cytosol metabolism
Daunorubicin metabolism
Galactosides metabolism
Glucosides metabolism
Humans
Prodrugs metabolism
Antibiotics, Antineoplastic pharmacology
Daunorubicin pharmacology
Glycosides metabolism
Prodrugs pharmacology
beta-Glucosidase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-2952
- Volume :
- 65
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Biochemical pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 12781339
- Full Text :
- https://doi.org/10.1016/s0006-2952(03)00183-7