Human stomach cancer cells undergo apoptosis by genistein, but not other genistein-and daidzein-related compounds

The effect of various isoflavones on the growth of human stomach cancer KATO III cells was investigated. Growth inhibition was greatest using genistein, followed by 8-hydroxygenistein (8-OHG), 8-hydroxydaidzein, and daidzein, respectively. Apoptosis induction in KATO III cells was observed following treatment with genistein, but not other compounds related to genistein or daidzein having the same isoflavone skeleton. Cells treated with genistein had morphological changes showing apoptotic bodies. The fragmentation of DNA by genistein to oligonucleosomal-sized fragments, a characteristic of apoptosis, was demonstrated to be concentration and time dependent by using agarose electrophoresis of DNA fragments isolated from the treated cells. The present study showed the positioning, but not the number of hydroxyl groups on the phenyl moiety of these isoflavones to be important for apoptosis-inducing ability.