Linked Life Data

16798057

Source:http://linkedlifedata.com/resource/pubmed/id/16798057

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2006-7-3
pubmed:abstractText
Thymidine phosphorylase (TP) and uridine phosphorylase (UP) catalyze the (in)activation of several fluoropyrimidines, depending on their catalytic activity and substrate specificity. Blood cells are the first compartment exposed to most anticancer agents. The role of white blood cells in causing toxic side effects and catalyzing drug metabolism is generally underestimated. Therefore we determined the contribution of the white blood cell compartment to drug metabolism, and we investigated the activity and substrate specificity of TP and UP for the (fluoro)pyrimidines thymidine (dThd), uridine (Urd), 5'-deoxy-5-fluorouridine (5' dFUrd) and 5-fluorouracil (5FU) in peripheral blood mononuclear cells (PBMC) and undifferentiated monocytes and differentiated monocytes: macrophages and dendritic cells. PBMC had an IC50 of 742 microM exposed to 5'dFUrd, increasing to > 2000 microM when both TP and UP activities were inhibited. Total phosphorolytic activity was higher with dThd than with Urd, 5'dFUrd or 5FU. Using a specific TP inhibitor (TPI) and UP inhibitor (BAU) we concluded that dThd and Urd were preferentially converted by TP and UP, respectively, while 5'dFUrd and 5FU were mainly converted by TP (about 80%) into 5FU and FUrd, respectively. 5FU was effectively incorporated into RNA. dThd conversion into thymine was highest in dendritic cells (52.6 nmol thymine/h/10(6) cells), followed by macrophages (two-fold) and undifferentiated monocytes (eight-fold). TPI prevented dThd conversion almost completely. In conclusion, PBMC were relatively insensitive to 5'dFUrd, and the natural substrates dThd and Urd were preferentially converted by TP and UP, respectively. TP and UP were both responsible for converting 5'dFUrd/5FU into 5FU/FUrd, respectively.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1357-2725
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1759-65
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
The role of thymidine phosphorylase and uridine phosphorylase in (fluoro)pyrimidine metabolism in peripheral blood mononuclear cells.
pubmed:affiliation
Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands.
pubmed:publicationType
Journal Article