Structure-Based Design and Synthesis of N-Substituted 3-Amino-β-Carboline Derivatives as Potent αβ-Tubulin Degradation Agents.

So far, relatively few small molecules have been reported to promote tubulin degradation. Our previous studies have found that compound , a noncovalent colchicine-site ligand, was capable of promoting αβ-tubulin degradation. To further improve its antiproliferative activity, 66 derivatives or analogues of were designed and synthesized based on -tubulin cocrystal structure. Among them, displayed nanomolar potency against a variety of tumor cells, including paclitaxel- and adriamycin-resistant cell lines. binds to the colchicine site and promotes αβ-tubulin degradation in a concentration-dependent manner via the ubiquitin-proteasome pathway. The X-ray crystal structure revealed that binds in a similar manner as , but there is a slight conformation change of the B ring, which resulted in better interaction of with surrounding residues. effectively suppressed tumor growth at an i.v. dose of 40 mg/kg (3 times a week) on both A2780S (paclitaxel-sensitive) and A2780T (paclitaxel-resistant) ovarian xenograft models, with respective TGIs of 92.42 and 79.75% without obvious side effects, supporting its potential utility as a tumor-therapeutic compound.