Thymidylate synthase and methylenetetrahydrofolate reductase gene polymorphisms: relationships with 5-fluorouracil sensitivity.

The relationship of thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms on 5-fluorouracil (FU) sensitivity was tested on 19 human cancer cell lines (head and neck, breast, digestive tract) in the absence and presence of folinic acid (FA) supplementation. Thymidylate synthase polymorphisms in the 5' promoter region (double or triple tandem repeats) and 3' untranslated region (6-bp deletion) were analysed by PCR. The C677T and A1298C MTHFR polymorphisms were determined by melting curve analyses (LightCycler).

Variable intrinsic sensitivity of human tumor cell lines to raltitrexed (Tomudex) and folylpolyglutamate synthetase activity.

The cytotoxic effects of Tomudex (TX) were investigated on a panel of 15 human tumor cell lines expressing a spontaneous sensitivity to the tested agent. We determined the basal cellular amount of relevant cellular factors potentially related to the cytotoxic efficacy of or resistance to TX. We selected thymidylate synthase (TS) as the target for TX, basal reduced folates (RF), because RF may compete with TX for a common site on the TS molecule.

Synthesis and Characterization of Nitrido Tc(V) and Re(V) Complexes with Ferrocenedithiocarboxylate {FcCS(2) = [Fe(C(5)H(4)CS(2))(C(5)H(5))](-)}.

The first mixed technetium-iron complexes [(99g)Tc(N)(FcCS(2))(2)] {FcCS(2) = [Fe(II)(C(5)H(5))(C(5)H(4)CS(2))](-)} (1) and [(99g)Tc(N)(FcCS(2))(FcCS(2)( bigstar))](+) {FcCS(2) = [Fe(II)(C(5)H(5))(C(5)H(4)CS(2))](-); FcCS(2)( bigstar) = Fe(III)(C(5)H(5))(C(5)H(4)CS(2))} (2) have been prepared and characterized. Complex 1 was obtained by reaction of the precursor complex [(99g)Tc(N)Cl(2)(PPh(3))(2)] with the piperidinium salt of the ligand FcCS(2). The resulting biferrocene complex is formed by two FcCS(2) ligands bound to the Tc atom through the four sulfur atoms of the two CS(2)(-) groups and bridged by a Tc&tbd1;N multiple bond.

Tumoral-reduced folates and clinical resistance to fluorouracil-based treatment in head and neck cancer patients.

Purpose: To describe the distribution of tumoral-reduced folates in cancer patients and to analyze the link between this parameter and antitumor efficacy of fluorouracil (FU)-based induction chemotherapy.

Patients And Methods: Ninety-five patients with head and neck squamous cell carcinoma were included in the present study and 41 received induction treatment with FU-based chemotherapy (35 men and six women; mean age, 59 years; range, 40 to 76). Thymidylate synthase (TS) activity was measured according to the tritium-release assay.

Relevance of tumoral folylpolyglutamate synthetase and reduced folates for optimal 5-fluorouracil efficacy: experimental data.

The purpose of this study was to investigate folate-related predictors of 5-fluorouracil (5-FU) cytotoxicity in the presence or absence of l-folinic acid (l-FA). Intracellular concentrations of the reduced folates (tetrahydrofolate + 5,10-methylenetetrahydrofolate) and folylpolyglutamate synthetase (FPGS) activity were determined in 14 human cancer cell lines expressing a spontaneous sensitivity to 5-FU. On these 14 cell lines grown without l-FA supplementation, a significant positive correlation was demonstrated between basal intracellular folate concentration and FPGS activity.