Inhibition studies of N_3-o-toluyl-fluorouracil on human gastric carcinoma cells growth through induction of apoptosis / 中国药理学通报

ABSTRACT

Aim To evaluate the efficacy of TFU as a precursor of 5-FU on the growth inhibition of human gastric carcinoma cell lines SGC-7901 and MKN-45.Methods In vitro experiments,cell growth inhibition was measured by MTT assay.The rates were compared in the presence and Absence of liver microsomal enzymes.The morphology of apoptotic cells was detected by observation with a fluorescence microscope after staining by using adridine orange/ethidium bromide solution.DNA fragmentation was analyzed by agarose gel electrophoresis and flow cytometry respectively.Western blot was employed to analyze the expression of Bcl-2 and Bax.The in vivo efficacy of TFU was assessed in nude mice bearing tumours.The specimens were re-moved and the in situ cell apoptosis detection kit was employed for TUNEL staining.Results Growth of SGC-7901 and MKN-45 cells was remarkably suppressed by treatment with TFU in the presence of liver microsomal enzymes in vitro,suggesting that TFU might be converted to 5-FU by the enzymes.Similar treatment of TFU induced apoptosis of the cells,which was deduced from typical apoptotic features such as morphology,the formation of characteristic ladder pattern of DNA migration and the accumulation of sub-G1 phase.Furthermore,a significant inhibition of Bcl-2 expression and the up-regulation of Bax were observed after treatment with TFU in the presence of liver microsomal enzymes.Growth of human gastric carcinoma cells was significantly delayed by oral administration of TFU with low side effects.Apoptosis in xenografts was also observed by means of TUNEL staining method.Conclusion Treatment of TFU in the presence of liver microsomal enzymes could promote the inhibition of gastric carcinoma cell proliferation.TFU might sustain release of 5-FU mediated by liver microsomal enzymes.Low dose of 5-FU might trigger the carcinoma cells apoptosis via regulation of Bax and Bcl-2.