[{"from": "human", "value": "Describe this molecule. [C][C][O][C][C][=C][C][=Branch1][=Branch2][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][N][C][=N][C][=C][Branch1][Ring2][O][Ring1][Branch1][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][N][C][C][N][C][Ring1][Branch1][=O]"}, {"from": "gpt", "value": "The molecule is a small molecule tubulin polymerization inhibitor with potential antineoplastic activity. Upon administration, tubulin polymerization inhibitor AB8939 binds to tubulin and prevents its polymerization in tumor blood vessel endothelial cells and tumor cells. This blocks the formation of the mitotic spindle and leads to cell cycle arrest at the G2/M phase. As a result, this agent disrupts the tumor vasculature and tumor blood flow, deprives tumor cells of nutrients and induces tumor cell apoptosis. In addition, this agent has a direct cytotoxic effect on tumor cells by inhibiting tubulin polymerization. Additionally, unlike similar agents of this class, AB8939 may be able to circumvent some drug resistance mechanisms."}]