Rapid disappearance of deoxyribose-1-phosphate in platelet derived endothelial cell growth factor/thymidine phosphorylase overexpressing cells.
Platelet derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) catalyzes the phosphorolysis of thymidine (TdR) to thymine and deoxyribose-1-phosphate (dR-1-P) and has a pro-angiogenic effect for which dR-1-P may be responsible. Using a purine nucleoside phosphorylase based assay it was found that TdR incubation did not increase dR-1-P accumulation in colon cancer cell line Colo320 and its PD-ECGF/TP transfected variant Colo320TP1. The assay was linear up to 25,000pmol dR-1-P with complete recovery of dR-1-P from cellular extracts. There was a huge discrepancy between thymine production and the measured dR-1-P level, 0.05% of the expected value for dR-1-P was found, indicating that there was a rapid disappearance of dR-1-P. However, in cellular extracts, TdR incubation increased dR-1-P, measurable by trapping, which was inhibited by a thymidine phosphorylase inhibitor. dR-1-P directly added to cellular extracts disappeared within 5-10min. In conclusion, large amounts of dR-1-P are produced by Colo320TP1 cells, which rapidly disappear thus not resulting in a net accumulation of dR-1-P in these cells.
de Bruin
M
M
Department of Medical Oncology, VU University Medical Center, Amsterdam, Netherlands.
Smid
K
K
Laan
A C
AC
Noordhuis
P
P
Fukushima
M
M
Hoekman
K
K
Pinedo
H M
HM
Peters
G J
GJ
D002460:Cell Line; D003110:Colonic Neoplasms / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D011683:Purine-Nucleoside Phosphorylase / Q000378:metabolism; D012267:Ribosemonophosphates / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D013939:Thymidine Phosphorylase / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D012267:Ribosemonophosphates; C031302:2-deoxyribose 1-phosphate; D011683:Purine-Nucleoside Phosphorylase; D013939:Thymidine Phosphorylase; D013936:Thymidine