A MELK inhibitor (IC50 = 37 nM); selective for MELK over CAMKIIδ, MNK2, CAMKIIγ, and MLCK (IC50s = 810, 760, 1,000, and 1,000 nM, respectively) but does inhibit FLT3 (IC50 = 18 nM); inhibits MELK autophosphorylation (IC50 = 0.52 µM) and MELK proteasome-dependent degradation in MCF-7 cells; induces cellular senescence and the ATM-mediated DNA damage response in MCF-7 cells