Effects of HG-7-85-01 on Kit, PDGFRα, and PDGFRβ gatekeeper mutants. (A) Approximately 3-day treatment of parental Ba/F3 cells and Ba/F3-Kit-T670I cells with nilotinib and HG-7-85-01, respectively. Error bars represent the SEM for proliferation studies performed in triplicate. (B) Comparison of the effects of imatinib (1000nM) and nilotinib (1000nM) on Ba/F3-T670I-luc⁺ cells. (C) Effect of HG-7-85-01 on gatekeeper mutant Kit-T670I phosphorylation: immunoblot of protein lysates prepared from Ba/F3-delWK+T670I cells treated for 2 hours with various concentrations of HG-7-85-01 (0-1μM). (D) Approximately 3-day treatment of T674M- and T674I-PDGFRα gatekeeper variants expressed in Ba/F3 with HG-7-85-01. (E) Comparison of the effects of HG-7-85-01, imatinib, and nilotinib on Ba/F3-T674M-PDGFRα cells. Error bars represent the SEM for proliferation studies performed in duplicate. (F) Effects of HG-7-85-01 on total cellular tyrosine phosphorylation in PDGFRα-T674M–expressing cells.