3-(3-Phenoxybenzyl)amino-ß-carboline: a novel antitumor drug targeting α-tubulin.

3-(3-Phenoxybenzyl)amino-ß-carboline 2h showed extremely-high activity; the IC(50) value was 0.074 µM. To verify 2h-induced cell death types, we observed the chromatin condensation, the DNA fragmentation and activated caspase-3 using Hoechst 33342, agarose electrophoresis and western blot, and suggesting 2h-induced cell death type was apoptosis. Flow cytometry showed that 2h-treated cell was induced SubG1 cell population after G2/M cell cycle arrest. In addition, using affinity chromatography and peptide mass fingerprinting, we found that interacting protein with this compound was α-tubulin protein.