Cantharidin as an antitumor agent: a retrospective review

This review summarizes the progress that has been made recently in the medicinal chemistry of cantharidin, a potent antitumor agent from traditional Chinese medicine. Thousands of analogs have been synthesized on the basis of cantharidin, a part of which shows excellent properties, in particular, norcantharidin and norcantharimide. Despite the enormous efforts made, the intriguing bioactivities, mechanism, indications, and their interplay are still ill-defined. This review provides our up-to-date understanding in connection with the therapeutic use, mechanism, structure-activity relationship (SAR) and interesting properties of cantharidin analogs. Considerable development in the design of cantharidin analogs, in combination with mechanistic studies, has laid a foundation for transforming novel antitumor drugs into the clinic.