Tumor selective self-assembled nanomicelles of carbohydrate-epothilone B conjugate for targeted chemotherapy.

Epothilone B (Epo B) is a potent antitumor natural product with sub-nanomolar anti-proliferation action against several human cancer cells. However, poor selectivity to tumor cells and unacceptable therapeutic windows of Epo B and its analogs are the major obstacles to their development into clinical drugs. Herein, we present self-assembled nanomicelles based on an amphiphilic carbohydrate-Epo B conjugate that is inactive until converted to active Epo B within the tumor. Four Epo B-Rhamnose conjugates linked via two linkers containing a disulfide bond that is sensitive to GSH were synthesized. Conjugate 34 can self-assemble into nanomicelles with a high concentration of Rha on the surface, allowing for better tumor targeting. After internalization by cancer cells, the disulfide bond can be cleaved in the presence of high levels of GSH to release active Epo B, thereby exhibiting significant anticancer efficiency and selectivity in vitro and in vivo.