The effect of fluoropyrimidines with or without thymidine phosphorylase inhibitor on the expression of thymidine phosphorylase

Michiel De Bruin, Toni Van Capel, Kees Smid, Masakazu Fukushima, Klaas Hoekman, Herbert M. Pinedo, Godefridus J. Peters

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Thymidine phosphorylase (platelet-derived-endothelial-cell-growth-factor) catalyzes the reversible phosphorolysis of thymidine to thymine and 2-deoxyribose-1-phosphate, activates 5′-deoxy-5-fluorouridine (5′DFUR) and inactivates trifluorothymidine (TFT). The effect of 5′DFUR and TFT with or without a specific thymidine phosphorylase inhibitor (TPI) on thymidine phosphorylase mRNA, protein expression and activity was studied, in three human colon cancer cell lines, WiDR, HT29 and Lovo exposed for 72 h at IC50 concentrations. In Lovo cells TFT plus TPI only increased thymidine phosphorylase-protein expression 1.7-fold; 5′DFUR and TFT treatment increased thymidine phosphorylase mRNA levels 5- and 1.4-fold, respectively. In WiDR cells, 5′DFUR plus TPI significantly decreased thymidine phosphorylase-protein. TFT and TFT plus TPI increased thymidine phosphorylase-protein 2- and 3-fold, respectively. TPI and 5′DFUR decreased thymidine phosphorylase-mRNA levels significantly. In HT29 cells, 5′DFUR and 5′DFUR plus TPI decreased both thymidine phosphorylase-protein and thymidine phosphorylase-mRNA. In all cell lines 5′DFUR and TFT did not affect thymidine phosphorylase activity, but treatment with TPI (alone or in combination) eliminated thymidine phosphorylase activity. This demonstrated that regulation is drug and cell line dependent.

Original languageEnglish (US)
Pages (from-to)93-99
Number of pages7
JournalEuropean Journal of Pharmacology
Issue number2-3
StatePublished - May 3 2004
Externally publishedYes


  • 5′-Deoxyfluorouridine
  • Thymidine phosphorylase
  • Thymidine phosphorylase inhibitor
  • Trifluorothymidine

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Pharmacology


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