NCI-H460 human non–small cell lung adenocarcinoma cells were suspended at 1 × 107 cells/mL in sterile PBS, and 100 μL were injected s.c. into the left inguinal region of female (9–10 wk old) CD-1 nu/nu mice. Three days later, mice were randomized into four groups (15 per group) and p.o. gavage dosing was initiated with vehicle (HPβCD) or with JNJ-28312141 at doses of 25, 50, and 100 mg/kg. Dosing was twice daily during the week and once daily on weekends for 25 consecutive days. JNJ-28312141 dose-dependently inhibited tumor growth.

Cell proliferation dependent on FLT3, KIT, and TRKA was assessed using MV-4-11 AML cells (ATCC CRL-9591), Mo7e erythroleukemia cells (DSMZ ACC-104), and TF-1 myeloid leukemia cells (ATCC CRL-2003), respectively. Cells were dispensed into microtiter plates (10,000 per well) together with graded concentrations of JNJ-28312141. Mo7e and TF-1 cultures were adjusted to contain 25 ng/mL stem cell factor or 1.4 ng/mL nerve growth factor, respectively. MV-4-11 cells were growth factor independent, due to an internal tandem duplication (ITD) of the FLT3 juxtamembrane domain, rendering FLT3 constitutively active (21). After a 72-h culture period, relative cell numbers were determined using CellTiterGlo reagent (Promega). MV-4-11 growth was calculated based on the difference between luminescence on day 3 versus day 0. M-07e and TF-1 growth was calculated based on the difference in luminescence of cells cultured in the presence versus the absence of growth factor. JNJ-28312141 inhibited the ITD-FLT3–dependent proliferation of MV-4-11 cells (IC50, 0.021 μmol/L), KIT-dependent proliferation of Mo7e cells (IC50, 0.041 μmol/L), and TRKA-dependent proliferation of TF-1 cells (IC50, 0.15 μmol/L).