Upregulation of platelet derived endothelial cell growth factor/thymidine phosphorylase by interferon alpha.

Thymidine phosphorylase (TP) catalyzes the phosphorolytic cleavage of thymidine to thymine and deoxyribose-1-phosphate. TP, which is overexpressed in a wide variety of solid tumors, is involved in the activation and inactivation of fluoropyrimidines. TP is known to be regulated by several cytokines and interferons. In our HT29 cell line the TP mRNA and activity expression increased 2-3 fold after treatment with interferon alpha.