Sodium butyrate induction of milk-related antigens in human MCF-7 breast carcinoma cells.

We have monitored the effects of sodium butyrate on expression of a human breast tumor-associated antigen defined by a murine monoclonal antibody designated DF3. This cell surface antigen has a molecular weight of approximately 300,000 and is related to a higher-molecular-weight antigen detectable in human milk. The results demonstrate that butyrate increases the membrane expression of the DF3 tumor-associated antigen. Further, butyrate treatment specifically enhances production of the DF3-related milk antigen. These effects occur at butyrate concentrations lower than that required for maximal expression of carcinoembryonic antigen and occur in the absence of changes in the expression of nonspecific cross-reacting antigen. The results suggest that butyrate induces a more differentiated MCF-7 phenotype and that this model may be useful in studying maturation of human breast cancer cells.