5-Fluoro-2 -deoxyuridine

Fig. 42 Prodrug [128] is an acylated derivative of the anticancer drug 5-fluoro-deoxyuridine. Antibody 49.AG.659.12, raised against phosphonate [127] was found to activate the prodrug [128] in vitro, thereby inhibiting the growth of E. coli.

Fig. 3. Metabolism of the fluoropyrimidines dTMP = deoxythymidine monophosphate, dUMP = deoxyuridine monophosphate, FdUDP = fluorodeoxyuridine diphosphate, FdUMP - fluoro-deoxyuridine monophosphate, FdUTP = fluorodeoxyuridine triphosphate, FU-DNA= fluorouracil-deoxyribonucleic acid, FUDP = fluorouracil diphosphate, FUMP = fluorouracil monophosphate, FU-RNA = fluorouracil-ribonucleic acid, FUTP = fluorouracil triphosphate.

Yoshioka A. Tanaka S, Hiraoka O, et al. Deoxyribonucleoside triphosphate imbalance. 5-fluoro-deoxyuridine-induced DNA double strand breaks in mouse FM3 A cells and the mechanism of cell death. J Biol Chem 1987 262 8235-8241. 

Although 5-fluorodeoxycytidine (fl5dC) (83) is more toxic than fl5dU (5-fluoro-deoxyuridine), and is less potent as an inhibitor of thymidylate synthase, there has recently been renewed interest in the antitumor activity of this analogue. Tumor cells have... 

When 5 -0-tritylthymidine-3 -phosphate is treated with excess tri-isopropyl benzenesulphonylchloride (TPS) and thymidine, and then deprotected, the trinucleoside monophosphate (7a) is obtained. The 5-bromo- and 5-fluoro-deoxyuridine analogues (7b) and (7c) are prepared similarly. All are resistant to snake venom and spleen phosphodiesterases, and hydrolyse too slowly under physiological conditions for the cytotoxic moiety to be effective. When protected UpU is treated with bis-(4-nitrophenyl) phosphorochloridate, and subsequently with an amine or amino-acid ester, the dinucleoside phosphor-amidates (8) are formed. Although the compounds investigated split the P—N bond under the conditions required for protecting-group removal, the method has potential for the preparation of easily fissionable neutral phospho-triesters. 

Figure 7.7-6. Duplex drugs. Structure of the anticancer amphiphilic heterodinucleosidyl phosphodiester (Duplex-drug) combining the hydrophilic 5-fluoro-deoxyuridine (5-FdU) with the lipophilic N -octadecyiarabino-furanosyicytosine (NOAC). Upon enzymatic hydrolysis of the duplex drugs, different anticancer nucleotides and nucleosides are formed with additive or synergistic activities.

In practice, investigators select the minimum concentration of BrdUrd that gives optimum differential staining of sister chromatids. For cultured fibroblasts, most investigators use about 10 ijlM BrdUrd. However, more consistent results are obtained with peripheral blood lymphocytes if BrdUrd is increased to about twice this concentration. Several laboratories use fluoro-deoxyuridine to depress the de novo synthesis of thymidine and increase the incorporation of BrdUrd Galloway has shown that fluorodeoxyuridine also increases the baseline frequency of SCE. 

P. A. Jones, J. V. Taderera. and A. O. Hawtrey, Transformation of hamster cells in vitro by 1-iS-D-arabinofuranosylcytosine, 5-fluoro-deoxyuridine and hydroxyurea, Eur. J. Cancer 8, 595-599 (1972). 

Lorenz M, Heinrich S, Staib-Sebler E,et al (2000) Relevance of locoregional chemotherapy in patients with liver metastases from colorectal primaries. Swiss Surg 6 11-22 Lorenz M, Waldeyer M (1997) The resection of the liver metastases of primary colorectal tumors. The development of a scoring system to determine the individual prognosis based on an assessment of 1568 patients. Strahlenther Onkol 173 118-119 Lorenz M, Muller HH (2000) Randomized multicenter trial of fluorouracil plus leucovorin administered either via hepatic arterial or intravenous infusion versus fluoro-deoxyuridine administered via hepatic arterial infusion in patients with nonresectable liver metastases from colorectal carcinoma (see comments]. J Clin Oncol 18 243-254... 

Thio-derivatives of 2 -deoxyuridine and S-fluoro-deoxyuridine (FDU) have been produced as a,p- mixtures by conventional coupling, whilst other workers have shown that, in the case of 2-thio-2 -deoxyuridine, the P-anomer can be produced stereoselectively at low... 

Fluorouracil (5-fluorouracil, 5-FU, Fig. 5) represents an early example of rational drag design in that it originated from the observation that tumor cells, especially from gut, incorporate radiolabeled uracil more efficiently into DNA than normal cells. 5-FU is a fluorinated pyrimidine analog that must be activated metabolically. In the cells 5-FU is converted to 5-fluoro-2>deoxyuridine-monophosphate (FdUMP). This metabolite inhibits thymidilate synthase which catalyses the conversion of uridylate (dUMP) to thymidilate (dTMP) whereby methylenetetrahydrofo-late plays the role of the carbon-donating cofactor. The reduced folate cofactor occupies an allosteric site of... 

Fluoro-2 -deoxyuridine has been extensively used in studies of the mechanism of action of thymidylate synthase, and 5-fluorouracil is an anticancer drug that has provided a lead to the development of others. The metabolism of 5-fluorouracil by the ascomycete fungus Nectria haematococca has been studied using F NMR (Parisot et al. 1991). a-Fluoro-P-alanine (2-fluoro-3-aminopropionate) was produced (Figure 10.27), while 5-fluorouridine-5 -mono-, di-, and triphosphate were found in acid extracts of the mycelia, and the 2 - and 3 -monophosphates were recovered from RNA. 

An interesting dinically useful prodrug is 5-fluorouracil, which is converted in vivo to 5-fluoro-2 -deoxyuridine 5 -monophosphate, a potent irreversible inactivator of thymidylate synthase It is sometimes charaderized as a dead end inactivator rather than a suicide substrate since no electrophile is unmasked during attempted catalytic turnover. Rathei since a fluorine atom replaces the proton found on the normal substrate enzyme-catalyzed deprotonation at the 5 -position of uracil cannot occur. The enzyme-inactivator covalent addud (analogous to the normal enzyme-substrate covalent intermediate) therefore cannot break down and has reached a dead end (R. R. Rando, Mechanism-Based Enzyme Inadivators , Pharm. Rev. 1984,36,111-142). 

D. J. Sweeney, S. Barnes, R. B. Diasio, Formation of Conjugates of 2-Fluoro-/3-alanine and Bile Acids during the Metabolism of 5-Fluorouracil and 5-Fluoro-2-deoxyuridine in the Isolated Perfused Liver , Cancer Res. 1988, 48, 2010-2014. 

The metabolic fate of trifluridine (11.17), an antiviral agent closely related to 5-fluoro-2 -deoxyuridine, was comparable. The main metabolite in the urine of mice administered the drug was the free 5-trifluorothymidine, i. e., the product of C-N bond cleavage [39]. All other metabolites were products of further biotransformation of trifluorothymidine. 

H. Foth, J. Hellkamp, E. M. Kunellis, G. E Kahl, Pulmonary Elimination and Metabolism of 5-Fluoro-2 -deoxyuridine in Isolated Perfused Rat Lung and Lung Slices , Drag Metab. Dispos. 1990, 18, 1011 - 1017. 

Schwendener RA, et al. 5 -0-palmitoyl- and 3, 5 -0-dipalmitoyl-5-fluoro-2 -deoxyuridine-novel lipophilic analogues of 5 -fluoro-2 -deoxyuridine synthesis, incorporation into liposomes and preliminary biological results. Biochem Bio-phys Res Commun 1985 126 660. 

Supersaxo A, et al. The antitumor effect of lipophilic derivatives of 5 -fluoro-2 -deoxyuridine incorporated into liposomes. J Microencaps 1988 5 1. 

Fig. 2. Structure of fluorouracil (5-FU) and floxuridine (5-fluoro-2 -deoxyuridine, FdUrd).

Ensminger WD, Rosowsky A, Raso V, et al. A clinical pharmacological evaluation of hepatic arterial infusions of 5-fluoro-2 -deoxyuridine and 5-fluorouracil. Cancer Res 1978 38 3784—3792. 

Kufe DW, Scott P, Fram R, et al. Biologic effect of 5-fluoro-2 -deoxyuridine incorporation in L1210 deoxyribonucleic acid. Biochem Pharmcol 1983 32 1337-1340. 

Danenberg PV, Heidelberger C, Mulkins MA, et al. The incorporation of 5-fluoro-2 -deoxyuridine into DNA of mammalian tumor cells. Biochem Biophys Res Commun 1981 102 654—658. 

Houghton JA, Houghton P, Wooten RS. Mechanism of induction of gastrointestinal toxicity in the mouse by 5-fluorouracil, 5-fluorourdine, and 5-fluoro-2 -deoxyuridine. Cancer Res 1979 39 2406-2413. 

Chadwick M, Chang C. Comparative physiologic dispositions of 5-fluoro-2 -deoxyuridine and... 

Waug J.-X., Suud X., and Zhang, Z.R., Enhanced brain targeting by synthesis of 3,5-dioctanoyl-5-fluoro-2-deoxyuridine and incorporation into sohd hpid nanoparticles, Eur. J. Pharm. Biopharm., 54, 285, 2002. 

Apart from Ro-28-2653, mentioned above, another important class of pyrimidine antitumor agents is represented by 5-fluorouracil (5-FU) 1035, which shows activity against a variety of different solid tumor types by functioning as an inhibitor of thymidylate synthase (TS) <2005CME2241>. 5-Fluoro-2 -deoxyuridine (FdUrd, floxuridine) 1036 is also widely used <2006JFC(127)303>. 

Fig. lA. Anabolic and catabolic pathways of 5-FU. DPD dihydropyrimidine dehydrogenase, DP di-hydropyrimidinase, pUP beta-ureidopropionase, UP uridine phosphorylase, OPRT orotate phospho-ribosyl transferase, UK uridine kinase, TP thymidine phosphorylase, TK thymidine kinase, RNR ribonucleotide reductase. The three active metabolites (shown in rectangles) are FdUMP (5-fluoro-2 -deoxyuridine 5 -monophosphate) inhibiting TS (thymidylate synthase), and FUTP (5-fluorouridine 5 -triphosphate) and FdUTP (5-fluoro 2 -deoxyuridine 5 -triphosphate) interfering with RNA and DNA, respectively. 

Fluorouracil (5-FU) is inactive in its parent form and requires activation via a complex series of enzymatic reactions to ribosyl and deoxyribosyl nucleotide metabolites. One of these metabolites, 5-fluoro-2 -deoxyuridine-5 -monophosphate (FdUMP), forms a covalently ternary complex with the enzyme thymidylate synthase and the reduced folate 5,10-methylenetetrahydrofolate, a reaction critical for the de novo synthesis of thymidylate. This results in inhibition of DNA synthesis through "thymineless death." 5-FU is converted to 5-fluorouridine-5 -triphosphate (FUTP), which is then incorporated into RNA, where it interferes with RNA processing and mRNA translation. 5-FU is also converted to 5-fluorodeoxyuridine-5 -triphosphate (FdUTP), which can be incorporated into cellular DNA, resulting in inhibition of DNA synthesis and function. Thus, the cytotoxicity of 5-FU is thought to be the result of combined effects on both DNA- and RNA-mediated events. 

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