Abstract
Taxol and vinblastine have been widely used in cancer chemotherapy as anti-microtubule agents. However, there are on-going efforts to find new anti-microtubule agents with fewer of the side effects associated with these drugs, such as toxicity or the development of resistance. The standard method used to identify anti-microtubule agents has been the in vitro microtubule polymerization assay. One limitation of this system is that the only compounds selected are those that act on tubulin. Novel compounds whose targets are upstream or are related unknown molecules are not detected. Therefore, many researchers have recently tried to develop novel, phenotype-based drug screening systems. In this study, we developed an oocyte-based screening system for anti-microtubule agents. Dramatic phenotypic changes in microtubules can easily be observed in ovulated oocytes treated with microtubule-stabilizing or -destabilizing agents, such as taxol or vinblastine. After culturing with test samples for 5 h, oocytes were analyzed with fluorescence microscopy after immunostaining. In the oocyte-based screening system, the effective dose (ED50) of taxol for microtubule polymerization is ~5 nM, and the ED50 of vinblastine for microtubule depolymerization is ~2.5 nM. In addition, taxol-like and vinblastine-like compounds can be evaluated simultaneously in a single assay using this system.
