EFFECT OF N-(4-HYDROXYPHENYL)RETINAMIDE ON APOPTOSIS IN HUMAN BREAST-CANCER CELLS

The synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) has been used in breast cancer prevention and treatment. However, the molecular mechanisms mediating the effects of 4-HPR remain elusive, In the pres ent study, we examined the effects of 4-HPR on components of apoptosis pathway (i.e. Bcl-2 and Bar) and apoptotic death in both estrogen rec eptor-positive and estrogen receptor-negative cell lines. We found tha t: (1) 4-HPR treatment resulted in decreased Bcl-2 mRNA but not Bar mR NA levels; (2) the effect of 4-HPR on Bcl-2 mRNA level was different f rom other retinoids; (3) 4-HPR treatment induced apoptosis in both est rogen receptor-positive and -negative cells. Hence, the breast cancer chemopreventive properties of 4-HPR may involve modulation of apoptosi s pathways.