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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2002-6-7
pubmed:abstractText
The selective activation of a relatively non-toxic prodrug by an enzyme present only in the tumour should enhance the drug concentration at the tumour site and result in a better anti-tumour effect and a reduction in systemic toxicity as compared to conventional chemotherapy. beta-Glucuronidase is such an enzyme. It is normally expressed in the lysosomes of cells. In larger tumours, however, high levels of the enzyme are present in necrotic areas. Several glucuronide prodrugs have been synthesised that can be activated by beta-glucuronidase. They are relatively non-toxic due to their hydrophilic nature, which prevents them from entering cells and thus from contact with lysosomal beta-glucuronidase. The main problem of glucuronide prodrugs for clinical use is their fast renal clearance. Special attention should be paid to the development of new less hydrophilic prodrugs with slower clearance, as this would result in a prolonged exposure to beta-glucuronidase at the site of the tumour and a reduction of the amount of prodrug needed. A number of interesting anthracyclin-based glucuronide prodrugs have been synthesised and have shown favourable therapeutic effects compared to treatment with the parent drug. The tumoural levels of beta-glucuronidase can even be enhanced by two-step approaches, in which exogenous enzyme is targeted to the tumour by an antibody (ADEPT) or by the gene encoding the enzyme in transduced tumour cells (GDEPT). The ADEPT and GDEPT approaches in combination with glucuronide prodrugs have shown enhanced efficacy in experimental tumour models. Further improvement of ADEPT and GDEPT is warranted to optimise the tumour uptake and retention of antibody-enzyme fusion proteins and the efficiency and safety of current gene delivery methods. In conclusion, it is clear that glucuronide prodrugs hold promise for future use in the treatment of cancer in patients as monotherapy. Enhancement of the therapeutic effects of glucuronide prodrugs, also in patients with small tumour lesions, may possibly be achieved by techniques that target beta-glucuronidase specifically to the site of the tumour.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1381-6128
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1391-403
pubmed:dateRevised
2006-2-27
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Beta-glucuronidase-mediated drug release.
pubmed:affiliation
Department of Medical Oncology, Division of Gene Therapy, Vrije Universiteit Medical Centre, P.O. Box 7057, Amsterdam, 1007 MB, The Netherlands.
pubmed:publicationType
Journal Article, Review