Different effects of the treatment with AGN 193836 and 9-cis-retinoic acidin breast cancer cells

Retinoid effects have been well studied in different cellular models, and t heir in vitro action on breast cancer is well known. Much less is known abo ut the function of the differ ent retinoid receptors in mediating retinoid activity in this and other cellular models. In order to better understand t hese biological mechanisms, sever al synthetic compounds have been produced that have .specifical binding affinity for selected nuclear receptors, and their effect has been evaluated and confronted with that of classic compou nds able to bind to different receptor. The aim of this study was the evalu ation of the biological activities in breast cancer cell lines of one of th ese new compounds, AGN 193836 with a very selective binding affinity (selec tive agonist retinoid) for one single retinoic acid receptor (RAR alpha), b z respect to a classic retinoid able to bind to a broad spectrum of retinoi c acid receptors (pan-agonist retinoid), 9cRA. Our results clearly indicate that the selective,retinoid retains most of the biological activities of t he pan-agonist compound but its effect is probably gravated by fewer side-e ffects in vivo: This evidences indicate that selective-agonist retinoids ar e an interesting research field for the future, not only because of their s peculative inter est, but also in view of future clinical applications.