Novel Prodrugs of Tegafur that Display Improved Anticancer Activity and Antiangiogenic Properties

New and more potent prodrugs of the 5-fluorouracyl family derived by hydroxymethylation or acyloxymethylation of 5-fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedione (tegafur, 1) are described. The anticancer activity of the butyroyloxymethyl-tegafur derivative 3 and not that of tegafur was attenuated by the antioxidant N-acetylcysteine, suggesting that the increased activity of the prodrug is in part mediated by an increase of reactive oxygen species. Compound 3 in an in vitro matrigel assay was found to be a more potent antiangiogenic agent than tegafur. In vivo 3 was significantly more potent than tegafur in inhibiting 4T1 breast carcinoma lung metastases and growth of HT-29 human colon carcinoma tumors in a mouse xenograft. In summary, the multifunctional prodrugs of tegafur display selectivity toward cancer cells, antiangiogenic activity, and anticancer activities in vitro and in vivo, superior to those of tegafur. 5-Fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedione (tegafur, 1), the...