Fig. 5: CX-5461 targets FGFR1 expression and eliminates residual breast cancer cells.

A Image of D2.A1 cells cultured on fibronectin fibrils that span unsupported space between the culture scaffold grids is taken 4 days after plating cells. Scale bar is 50 μm. B D2.A1 cells were cultured on FN-coated scaffolds or standard tissue culture plastic (2D) for 6 days in the presence of the indicated concentrations of CX-5461 and cell viability was measured (n = 3). C Immunoblot analyses for FGFR1 following 4 days treatment with the indicated concentrations of CX-5461. D D2.A1 spheroids expressing firefly luciferase were formed in a round bottom plate and then transferred to a bed of matrix in the presence or absence of 20 ng/ml FGF2, 100 nM Erdafitinib (Erd), or 100 nM CX-5461 (CX). Scale bars are 1000 μm. Following 6 days of culture bioluminescence was measured and treated values were normalized to non-stimulated (NS) spheriods. Data are the mean ±s.e.m. (n = 3). E As in panel D, firefly luciferase expressing D2.OR cells were used in a spheroid growth assay. Scale bars are 1000 μm. F Following 3D culture, D2.OR spheroids were disassociated and single cells were plated on tissue culture plastic. Colony formation in 10cm² tissue culture dishes was visualized by crystal violet staining after 14 days and cells were solubilized and read at an absorbance 600 nm. For all panels *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001.