In vitro activity: In FGFR1-4 Ba/F3 cells, FIIN-2 inhibits cell proliferation with EC50 in the single- to double-digit nanomolar range. FIIN-2 also shows excellent antiproliferative activity in a variety of backgrounds, including cell lines that have gatekeeper mutations in FGFR1 and that are dependent on FGFR4.

Kinase Assay: Biochemical assays are performed by a broad-coverage, TR-FRET-based kinase binding assay platform.

Cell Assay: NCI-H2077, NCI-H1581, H520, Kato III, AN3CA, RT112, A2780, 4T1, and SKOV-3 cells are treated with inhibitors 1 d after being plated at a density of 1,500 cells per well in 96-well plates. The gatekeeper mutation cell lines are generated by ectopically overexpressing FGFR1 V561M in either NCI-H2077 or NCI-H1581 cells via lentiviral transduction. Cell survival is assessed at 96 h following the addition of inhibitor using the Cell-Titer-Glo reagent according to the manufacturer’s instructions. EC50 values are calculated using GraphPad Prism 5. SKOV-3 cells also are treated in the presence of FGF or EGF ligand. Proliferation measurements were made after 96 h using a luminometer. Data are shown as relative values: The luminescence of cells with indicated inhibitor dose is compared with that of untreated cells.