Effect of genistein combined with 5-fluorouracil on proliferation and apoptosis in colon cancer SW480 cells in vitro

OBJECTIVE:To investigate the effect of genistein combined with 5-FU on the proliferation and apoptosis of human colon carcinoma cell SW480 in vitro.METHODS:The growth inhibitory effects of genistein and 5-FU on SW480 cells were studied by MTT assay.TUNEL technology was used to investigate the apoptosis of the cells and electron microscopy was used to observe the ultra-microstructure changes of tumor cells.The cell cycle distribution was detected by flow cytometry(FCM) after using drugs.RESULTS:1) Both genistein and 5-FU exhibited a dose-and time-dependent inhibitory effect on the proliferation of SW480 cells.2)The combination of genistein and 5-FU excerted a synergistic effect on SW480 cell growth inhibition.5-FU in the concentration of 30 μg/mL and genistein in the concentration of 80 μmol/L interaction with 48 h was the most synergistic (CI=0.51).3) In TUNEL,both genistein and 5-FU alone or tegether caused SW480 cell apoptosis especially combination.4) The nucleus electron density increased,and there were nuclear fragmention of apoptotic cells and apoptotic bodies by electron microscopy,and all of which were most significant in the group of two drugs.5) FCM showed a G2 arrest on SW480 cells after the treatment of genistein,being different from the mechanism of 5-FU.CONCLUSIONS:The synergistic antitumor effect of genistein with 5-FU by inducing the apoptosis on SW480 cells.This combination appears to be a new idea for increasing the antitumor effect of chemotherapic drugs on colon carcinoma.