SKLB610, a novel multi-targeted inhibitor, inhibits angiogenesis-related tyrosine kinase VEGFR2, FGFR2, and PDGFR at a rate of 97%, 65%, and 55%, respectively, at the concentration of 10 μM in biochemical kinase assays.

PI3K assay: PI3K assay is preformed on whole-cell lysates from CLL or normal B cells. A PI3K ELISA assay is performed. Briefly, whole-cell extracts are added to a mixture of PI(4,5)P2 substrate and reaction buffer containing adenosine triphosphate (ATP) and allowed to incubate at room temperature. The reaction is stopped by adding PI(3,4,5)P3 detector mixed with EDTA (ethylenediaminetetraacetic acid) and allowed to incubate at room temperature for 1 hour. After this time, the mixture is transferred from each well to a PI3K ELISA plate and allowed to incubate 1 hour. Plates are washed and then incubated with secondary detector for 30 minutes. Plates are washed again, and 3,3′,5,5′-tetramethylbenzidine solution is added for 5 minutes at which time H2SO4 is added to stop all reactions. Plates are read at 450 nm on a Labsystems 96-well plate reader.