In vitro antitumour activity of cis- and trans-5-fluoro-5,6-dihydro-6-alkoxy-uracils ; effects on thymidylate synthesis

• Published in: British journal of cancer Vol. 68; no. 4; pp. 702 - 707
• Main Authors: VAN DER WILT, C. L, VISSER, G. W. M, BRAAKHUIS, B. J. M, WEDZINGA, R, NOORDHUIS, P, SMID, K, PETERS, G. J
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.10.1993
• Subjects: Antineoplastic agents; Biological and medical sciences; Carcinoma, Squamous Cell - drug therapy; Carcinoma, Squamous Cell - enzymology; Carcinoma, Squamous Cell - pathology; Cell Division - drug effects; Deoxyuridine - metabolism; DNA, Neoplasm - metabolism; Drug Screening Assays, Antitumor; Fluorouracil - analogs & derivatives; Fluorouracil - therapeutic use; General aspects; Humans; Laryngeal Neoplasms - drug therapy; Laryngeal Neoplasms - enzymology; Laryngeal Neoplasms - pathology; Medical sciences; Mouth Neoplasms - drug therapy; Mouth Neoplasms - enzymology; Mouth Neoplasms - pathology; Pharmacology. Drug treatments; Thymidylate Synthase - metabolism; Tumor Cells, Cultured; Antineoplastic agent; Human; Enzyme; Transferases; Enzyme inhibitor; Cytotoxicity; Malignant tumor; Thymidylate synthase; In vitro; Pyrimidine base derivatives; Methyltransferases; Analog; Established cell line; Fluorine Organic compounds
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/bjc.1993.413

A class of new 5-fluorouracil (FU) analogues, the 5-fluoro-5,6-dihydro-6- alkoxy-uracils was synthesised with a modification at the 6-position of the pyrimidine ring. At this position the analogues have a hydroxy or alkoxy group of different chain lengths either in the cis- or trans-configuration. The antiproliferative effect of these compounds was tested on five cell lines of different origin. Generally, the analogues with a cis-configuration had a higher activity than those with a trans-configuration. The growth inhibitory effect of the compounds decreased with increasing alkoxy chain length, but the compound with a hydroxy group had the lowest growth inhibitory effect. One analogue, cis-5-F-5,6-dihydro-6-methoxy-uracil had a higher antiproliferative effect than FU in one of the cell lines. Effects on thymidylate synthase (TS), the possible target of these analogues, were evaluated by thymidine rescue of growth inhibition and incorporation of tritiated deoxyuridine (3H-UdR) into DNA. In solid tumour cell lines addition of TdR reversed the antiproliferative effect. Inhibition of TS in intact cells was determined by measuring 3H-UdR incorporation in two cell lines. The effect of cis-5-F-5,6-dihydro-6-methoxy-uracil on incorporation of 3H-UdR was 2- to 5-fold stronger than that of FU in both cell lines. All other compounds produced a higher 3H-UdR incorporation than FU both at equimolar and equi-toxic concentration. Concluding from these results we regard cis-5-F-5,6-dihydro-6-methoxy-uracil as the most promising FU analogue of this series, because of its higher antiproliferative activity than FU and marked inhibition of TS in intact cells.