Structure and functional activity of imidazo[1,2-b]pyridazine compound SGI-1776. (A) Chemical structure of SGI-1776. (B) Kinase inhibition by SGI-1776. Several human kinases were tested for selective inhibition by 1 μmol/L SGI-1776 using Millipore kinase profiler assay as described in “Kinase assays.” (C) In vitro kinase assays of Pim-1, -2, and -3 with varying concentrations of SGI-1776 to determine IC₅₀ values for each Pim kinase species. The IC₅₀ Profiler Express Assay is described in “Kinase assays.”