All-trans-retinoic acid mediates G1 arrest but not apoptosis of normal human mammary epithelial cells

Retinoids mediate the normal growth of a variety of epithelial cells and may play an Important role in the chemoprevention of certain malignancies. Loss of retinoic acid (RA) receptor-fl function may be an important event in mammary carcinogenesis, because the majority of breast cancers, in contrast to normal mammary epithelial cells, fail to express this receptor. We previously reported that aII-trans-RA mediates G1 arrest as well as apoptosis in certain RARI3-transduced breast cancer cell lines. We now report the effect of