Effect of bFGF on the MCF-7 Cell Cycle with CD44+/CD24-: Promoting the G0/G1→G2/S Transition

PURPOSE Few cells with stem cell characteristics possess capabilities of self-renewal and differentiation, which leads to high tumorigenesis and resistance to standard chemotherapeutic agents. These cells are mostly quiescent, and arrest occurs at the mitotic G0/G1 phase in mitosis. We explored the effects of basic fibroblast growth factor (bFGF) on the MCF-7 cell cycle with CD44(+)/CD24(-). METHODS Cancer-initiating cells were propagated as mammospheres. The CD44(+)/CD24(-) subpopulation was sorted by a fluorescence activating cell sorter-Vantage flow cytometer. A cell cycle analysis was performed with different bFGF concentrations. RESULTS Differences in the CD44(+)/CD24(-) cell proliferation under different bFGF concentrations were observed (p=0.001). When the bFGF concentration was increased, the proportion of CD44(+)/CD24(-) at G0/G1 decreased (p=0.023). CONCLUSION We conclude that bFGF may sustain CD44(+)/CD24(-) cell proliferation and could promote cell progression through the G0/G1→G2/S phase transition.