Colcemid is a colchicine derivative that inhibits tubulin polymerization as potently as colchicine (IC50 = 2.1 and 2.4 μM, respectively) but is less toxic. At very low (nanomolar) concentrations, colcemid suppresses microtubule dynamicity and inhibits cell migration, while at micromolar levels it blocks microtubule assembly, arresting cells in metaphase. Mitotic block by colcemid is used to synchronize cells and for karyotyping in cytogenetic studies. Prolonged exposure to colcemid can activate p53, leading to apoptosis.
