Importazole

Importazole is a 2,4-diaminoquinazoline that inhibits the function of transport receptor importin-β, likely by altering its interaction with RanGTP. Importazole prevents nuclear import of GFP-tagged nuclear factor of activated T cells (NFAT-GFP) in HEK293 cells with an IC₅₀ of 15 μM, which is reversible upon importazole washout. Importazole inhibits nuclear import of topoisomerase IIβ binding protein 1 (TopBP1) in Xenopus egg extracts and NF-κB in multiple myeloma cells. It induces apoptosis and inhibits growth of multiple myeloma cell lines with IC₅₀ values of 4.4 μM and 4.8 μM, respectively. It also induces defects in astral MT dynamics and misoriented spindles.