Estrogen and tamoxifen induced cytoskeletal changes in breast cancer cells.

The MCF-7 and CG-5 breast carcinoma cell lines were grown under different concentrations of estrogen and with or without the addition of tamoxifen to the media. Similar results were obtained with either cell lines. Cells cultured in estrogen-supplemented medium showed a marked change of the cell shape with the appearance of long projections sprouting from the cell body, adhesion areas being localized at the tips of these projections. A redistribution of bundles of prekeratin and actin fibres could be visualized by appropriate immuno-cytochemical procedures. Vimentin intermediate filaments and microtubules did not appear significantly modified by hormone conditioning. Tamoxifen treatment resulted in structural and cytoskeletal changes similar to those observed in estrogen stimulated cells. These data indicate that the shape and the cytoskeletal architecture of breast cancer cells can be conditioned by hormone treatment.