TY - JOUR T1 - Selective inhibition of spindle microtubules by a tubulin-binding quinazoline derivative JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.119.116624 SP - mol.119.116624 AU - Jun-ichi Sawada AU - Hirosuke Ishii AU - Kenji Matsuno AU - Masayuki Sato AU - Yumiko Suzuki AU - Akira Asai Y1 - 2019/01/01 UR - http://molpharm.aspetjournals.org/content/early/2019/08/30/mol.119.116624.abstract N2 - In the research field of tubulin-binding agents for the development of anticancer agents, hidden targets are emerging as a problem in understanding the exact mechanisms of actions. The quinazoline derivative PVHD121 has anti-cell proliferative activity and inhibits tubulin polymerization by binding to the colchicine site of tubulin. However, the molecular mechanism of action of PVHD121 in cells remains unclear. Here, we demonstrate that PVHD121 delays mitotic entry and efficiently causes mitotic arrest with spindle checkpoint activation, leading to subsequent cell death. The dominant phenotype induced by PVHD121 was aberrant spindles with robust microtubules and unseparated centrosomes. The microtubules were radially distributed, and their ends appeared to adhere to kinetochores, and not to centrosomes. Extensive inhibition by high concentrations of PVHD121 eliminated all microtubules from cells. PVHD277, a PVHD121 derivative with fluorescence, tended to localize close to the centrosomes when cells prepared to enter mitosis. Our results show that PVHD121 is an antimitotic agent that selectively disturbs microtubule formation at centrosomes during mitosis. This antimitotic activity can be attributed to the targeting of centrosome maturation in addition to the interference with microtubule dynamics. Due to its unique bioactivity, PVHD121 is a potential tool for studying the molecular biology of mitosis and a potential lead compound for the development of anticancer agents.SIGNIFICANCE STATEMENT Recent reports about the detailed studies of protein kinase inhibitors highlight the importance of understanding the exact mechanisms of action of tubulin-binding agents, taking into account the existence of hidden target biomolecules. We here report a study on the mechanism of action of PVHD121, a quinazoline derivative binding to the colchicine site of tubulin. By detailed analyses of its effect on cells and its subcellular distribution, our study revealed that PVHD121 is an antimitotic agent and selectively inhibits spindle microtubule formation at centrosomes. This antimitotic activity is attributed to the targeting of centrosome maturation, in addition to the interference with microtubule dynamics. This bioactivity clearly distinct from colchicine, a conventional tubulin-binding agent. Our study provides useful information and novel views of tubulin-binding agents, and indicates the importance of detailed analysis of the effects of tubulin-binding agents on cells. ER -