Microtubule integrity checkpoint

Microtubule-depolymerising agents disrupt microtubule function by binding to specific sites on β-tubulin subunits; consequently they are ideal for use in cell synchronization studies and also in the treatment of several cancers. In 1 July Journal of Clinical Investigation, April Blajeski and colleagues at the Mayo Clinic, Rochester, US, show that microtubule-depolymerizing agents can arrest cells before mitosis and that the biochemistry of this process is more complicated and diverse than previously anticipated (J Clin Invest 2002, 110:91-99).

Blajeski et al. examined the effect of the drugs nocodazole, vincristine and colchicine on normal and malignant human breast cell lines. They observed that instead of a mitotic arrest, a subset of the cell lines responded to high drug concentrations with a depolymerization of microtubules and a pre-mitotic G1 and G2 arrest that prevented the cells from ever reaching mitosis. In addition, this subset correlated with p53-independent induction of p21.

These results raise ...