The Inhibition Of Carcinoma Cell Growth And Mechanism By N₃-o-toluyl-fluorouracil

N₃-o-toluyl-fluorouracil (TFU) is the derivative of atofluding, N₁-acetyl-N₃-o-toluyl-fluorouracil, and the prodrug of 5-FU. Nevertheless, the acetyl group on the N₁ position of atofluding is not stable and is prone to decompose, impairing quality control for the preparation. Moreover, the clinically effective dosage of 5-FU is very close to its toxic dosage when given intravenously, resulting in its strong toxicities to the gastric and intestinal mucosa and the bone marrow. In addition, its plasma half-life is very short (15-20 min) and the drug is administered only as a continuous i.v. infusion. In order to overcome these disadvantages, attempts were made to design and synthesize new 5-FU derivatives. In this study, we evaluated the efficacy of TFU to inhibit the growth of carcinoma cells with the aim of replacing the unstable atofluding.Methods: In vitro studies: The growth of tumour cells and the efficacy of TFU were evaluated by MTT assay. The enhancement of growth inhibition is measured in the presence of liver microsomal enzymes. In vivo studies: The effects of TFU on the transplantable sarcinoma S180 and hepatoma cells of H22 in mice were examined after 2 weeks oral administration. The effects of TFU on human gastric carcinoma cell xenografts in nude mice were then studied. In the studies of apoptosis, the apoptotic cells were detected after staining with adridine orange/ethidium. The quantification of DNA ladder was done by agarose gel electrophoresis. The rates of apoptosis cells were subjected to PI staining and analyzed by a flow cytometry. The in situ cell apoptosis detection kit was used to measure the apoptotic cells in xenografts. Results: Human gastric carcinoma cells SGC-7901 and MKN-45 were treated with TFU and then the rate of cell growth inhibition was evaluated based on the viable cell...