In vitro modulation of MCF-7 breast cancer cell growth by myoepithelial cells

Growth and differentiation of MCF-7 breast adenocarcinoma cells were studied in mixed cultures of MCF-7 cells and PA 16/23 myoepithelial cells and in isolated cultures of MCF-7 cells grown in the absence and presence of conditioned medium of PA 16/23 cells. In the cocultures, the MCF-7 cells grew in smaller aggregates and showed a more differentiated phenotype than in the isolated cultures. The conditioned medium of PA 16/23 cells enhanced growth and reduced differentiation of the MCF-7 cells. Hence, a direct relationship between MCF-7 cells and PA 16/23 cells seems to play a leading role in influencing the behaviour of the former cells, thus overriding the opposite effects of soluble factors secreted by the PA 16/23 cells.