Cytosolic β-glycosidases for activation of glycoside prodrugs of daunorubicin

Michelle De Graaf, Herbert M. Pinedo, Razi Quadir, Hidde J. Haisma, Epie Boven

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Human cytosolic β-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 β-glycosidase converted both prodrugs to daunorubicin as shown by liquid chromatography. The kinetics of the conversion of DNR-GlA3 and DNR-GsA3 by human β-glycosidase, however, was unfavorable as the Km values were, respectively, 3- and 6-fold higher than those of another mammalian β-glycosidase of bovine origin. The Vmax 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 β-glycosidase (0.5U/mL) and 0.5μM 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 β-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 β-glycosidase or by evolution of the enzyme into a mutant form that displays high activity towards these prodrugs.

Original languageEnglish (US)
Pages (from-to)1875-1881
Number of pages7
JournalBiochemical Pharmacology
Issue number11
StatePublished - Jun 1 2003
Externally publishedYes


  • Anthracyclines
  • Cancer chemotherapy
  • Cytosolic β-glycosidase
  • Galactoside
  • Glucoside
  • Prodrug

ASJC Scopus subject areas

  • Pharmacology


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