Differential responsiveness of human breast cancer cells to basic fibroblast growth factor: a cell kinetics study

The effects of basic fibroblast growth factor (bFGF) on breast cancer cells are still contradictory and not fully understood. We have studied the effect of bFGF on the cell cycle kinetics of two breast cancer cell lines (MCF-7 and MDA-MB-231) and an immortalized cell line (HBL-100). The methodology included use of microscopic image analysis with cell numeration, Feulgen staining, Proliferating Cell Nuclear Antigen/Ki-67 immunodetection and bromodeoxyuridine incorporation. We show that bFGF is mitogenic for MCF-7 cells via a mechanism of recruitment of G0 phase cells to reenter into the cell cycle and by decreasing the G1 phase length. No effect of bFGF on cell cycle parameters has been found with either highly metastatic MDA-MB-231 cells or immortalized HBL-100 cells. These results reveal differences in bFGF responsiveness of breast epithelial cells.