3-(3,4,5-Trimethoxyphenylselenyl)-1H-indoles and their selenoxides as combretastatin A-4 analogs: microwave-assisted synthesis and biological evaluation.

A series of 3-(3,4,5-trimethoxyphenylselenyl)-1H-indoles and their selenoxides were designed as a new class of combretastatin A-4 (CA-4) analogs. The B ring and the cis double bond of CA-4 were replaced by an indole moiety and selenium atom, respectively. A facile and efficient microwave-assisted synthesis of 3-arylselenylindoles was developed to prepare the target compounds, which were then evaluated for antiproliferative activity against three human cancer cell lines using an MTT assay. Most of these compounds exhibited significant antiproliferative activity, with some showing nanomolar IC50 values. Tubulin polymerization and immunostaining experiments revealed that 13a potently inhibited tubulin polymerization and disrupted tubulin microtubule dynamics in a similar manner to CA-4. Docking studies demonstrated that 13a adopts an orientation similar to that of CA-4 at the colchicine binding site on tubulin.