Fig. 1: Inhibition of FGFR kinase activity suppresses tumor growth but fails to eliminate dormant breast cancer cells.

A Representative bioluminescence imaging (BLI) images of control and erdafitinib (Erd) treated (50 mg/kg/po/qd) mice bearing 4T07 pulmonary tumors monitored by bioluminescence 13 days following tail vein inoculation. B Bioluminescent values from pulmonary regions of interest (ROI) were normalized to the values at the initial day of injection. Data are the individual values for each mouse (n = 5) per treatment group. C Kaplan-Meier analyses of control and erdafitinib treated mice, bearing 4T07 pulmonary tumors, resulting in the indicated p-value. D 4T07 spheroids expressing luciferase were formed in non-adherent round bottom plates and then plated onto a bed of matrix in the presence or absence of FGF2 (20 ng/ml) or the indicated FGFR inhibitors (100 nM). E D2.A1 cells expressing luciferase were similarly used in spheroid culture, treated, and analyzed as in panel D. F D2.OR cells expressing luciferase were similarly used in spheroid culture, treated, and analyzed as in panels D and E. Luminescence values at day 6 were normalized to the non-stimulated (NS) conditions. Scale bars in panels D–F are 1000 μm. Data are the mean ± s.e.m. (n ≥ 3) where *p < 0.05. G Following 3D culture, D2.OR spheroids were trypsinized and single cells were plated on tissue culture plastic. Colony formation in 10 cm² tissue culture dishes was visualized by crystal violet staining 14 days later as a measure of dormant cell survival.