[Application of NGF/PC12 cell system for screening tubulin inhibitors]

Microtubules are stiff polymers that extend throughout the cytoplasm of eukaryotic cells and regulate the location of intracellular compartments. Microtubules are formed by the polymerization of tubulin molecules, each of which is a heterodimer consisting of two closely related globular polypeptides, alpha-tubulin and beta tubulin. Many of the microtubule arrays are labile and are turning over rapidly; they depolymerize and repolimerize continually in living cells. One of the most striking examples is the mitotic spindle, which forms after the cytoplasmic microtubules disassemble at the onset of mitosis. The mitotic spindle is the target of a variety of agents that act by interfering with the exchange of tubulin subunits between the microtubules and the free tubulin pool; some of these agents can be used as antimitotic or anticancer drugs. We recently have developed a simple and sensitive method of screening for tubulin inhibitors, to which we have successfully applied the nerve growth factor/PC12 cell system. In this report, we describe the details of this method for screening tubulin inhibitors, by which we have analyzed several well-known and new compounds a model experiments.