Relationship between cell migration and cell cycle during the initiation of epithelial to fibroblastoid transition

The NBT-II rat bladder carcinoma cell line, which displays epithelial to me senchymal transition or EMT in response to FGF-1 stimulation, was used to s tudy the interrelationships between cell cycle and cell scattering and loco motion. Time-lapse video microscopy experiments were performed with asynchr onous growing cells and lovastatin-arrested cells. FGF-1 stimulation induce d cell movement in cells in all phases of the cell cycle, except G2 + M pha se, in which cells did not respond to stimulation. The delay between cell s timulation and cell movement depended on the age of the cell at the beginni ng of cell stimulation: cells less than 4 h old when stimulated by FGF-1 ha d a 1-h delay whereas cells more than 4 h old had a 3-h delay. Cells stimul ated before they were 4 h old were temporarily arrested in their cell cycle progression. Older cells underwent mitosis on schedule. Lovastatin-treated cells were shown to be synchronized in the G1 phase and to migrate simulta neously after FGF-1 stimulation. These results indicate that the G1 phase w as a critical phase for FGF-1 induced cell migation during epithelial to fi broblastoid transition. Cell Motil. Cytoskeleton 43:288-295, 1999. (C) 1999 Wiley-Liss, Inc.