Potent antitumor activity of novel taxoids in anaplastic thyroid cancer

Purpose: Anaplastic thyroid cancer (ATC) is the most aggressive form of thyroid cancers and it is rapidly fatal without any effective therapeutic regimens. There are some clinical trials showing that paclitaxel-based chemotherapy for ATC can achieve a relatively high response rate and low incidence of adverse reaction. The aim of this study was to evaluate potential therapeutic activity of novel taxoids in ATC cells. Methods: We evaluated antitumor activity of five novel 3′-difluorovinyltaxoids (DFV-taxoids) in anaplastic thyroid cancer cells by a series of in vitro and in vivo experiments. Besides, we also explored the potential mechanism underlying the difference among the taxoids and paclitaxel by molecular docking and tubulin polymerization assays. Results: Our data showed that these novel DFV-taxoids were more effective than paclitaxel in ATC cell lines and xenografts, as reflected by the inhibition of cell proliferation, colony formation and tumorigenic potential in nude mice, and the induction of G₂/M phase arrest and cell apoptosis. Using tubulin polymerization assays and molecular docking analysis, we found that these DFV-taxoids promoted more rapid polymerization of β-tubulin than paclitaxel. Conclusions: Our data demonstrate that these novel taxoids exhibit stronger antitumor activity in ATC cells than paclitaxel, thereby providing a promising therapeutic strategy for the patients with ATC.