Progesterone treatment decreases sulfate carbohydrate antigen on endometrial carcinoma cells and inhibits the cell binding to laminin.

To investigate the effects of progesterone on endometrial carcinoma, sulfated carbohydrate antigen was studied using a monoclonal antibody, termed E8, that reacts with sulfatide. The reactivity of monoclonal antibody (MAb) E8 with endometrial carcinoma tissues decreased when patients were treated with medroxyprogesterone acetate (MPA). A reduction of reactivity of MAb E8 with endometrial carcinoma cells was also observed in in vitro examinations using an endometrial carcinoma cell line, Ishikawa cells incubated in MPA-containing medium. Sulfated carbohydrate, such as sulfatide, is the site of binding with laminin. The binding of cell surface components with laminin is thought to be an initial step in the invasion and metastasis of carcinoma cells. The MPA-treated Ishikawa cells bound to laminin-coated dishes less [corrected] efficiently than nontreated cells. MPA treatment of endometrial carcinoma reduces the sulfatide carbohydrate on the carcinoma cell surface and may be clinically more effective in reducing cell binding to laminin.