Taxol stabilizes microtubules in mouse fibroblast cells

Taxol, a potent inhibitor of human HeLa and mouse fibroblast cell replication, blocked cells in the G₂ and M phase of the cell cycle and stabilized cytoplasmic microtubules. The cytoplasmic microtubules of taxol-treated cells were visualized by transmission electron microscopy and indirect immunofluorescence microscopy. More than 90% of the cells treated with 10 μM taxol for 22 hr at 37°C displayed bundles of microtubules that appeared to radiate from a common site (or sites), in addition to their cytoplasmic microtubules. Untreated cells that were kept in the cold (4°C) for 16 hr lost their microtubules, whereas cells that were pretreated with taxol for 22 hr at 37°C continued to display their microtubules and bundles of microtubules in the cold. Taxol inhibited the migration behavior of fibroblast cells, but these cells did not lose their ability to produce mobile surface projections such as lamellipodia and filopodia.