Fig 1: Quisinostat can also sensitize BC cells to erdafitinib by downregulating HDGF.a RNA-seq results showing the representative genes that are downregulated by quisinostat in all three BC cells. b RT-qPCR results showing the HDGF mRNA level with or without quisinostat treatment. Cells were treated by quisisnostat for 2 days and then harvested for RT-qPCR. All results were first normalized to β-actin (ACTB) loading control and then normalized to DMSO control of each cell line. Data were plotted as mean ± SEM from four biological replicates and statistics were calculated by t tests (****p < 0.0001). c Western blots showing the HDGF protein expression level with or without quisinostat treatment. Cells were treated by quisisnostat for 2 days and then harvested for western blotting. β-actin (ACTB) was used as standard loading control. d Quantification of (c) by ImageJ. Results were normalized to DMSO control for each cell line. Data were plotted as mean ± standard deviation from three biological replicates and statistics were calculated by t tests (****p < 0.0001). e TCGA analysis of the bladder cancer cohort showing that HDGF expression is higher in bladder cancer patients than in healthy tissue. Statistics were calculated by one-way ANOVA (*p < 0.05). Center lines represent the median value, upper and lower bounds of the boxes denote the upper and lower quartiles, upper and lower whiskers represent the 1.5x interquartile range, and data points outside the upper and lower whiskers are considered outliers. f Western blots showing that both siRNAs of HDGF (siHDGFs) can successfully knock down HDGF without affecting the expression of FGFR3 fusions in SW780 and RT112 cells. β-actin (ACTB) was used as standard loading control. C, siRNA of non-targeting control. g, h Cell viabilities of SW780 cells (g) and RT112 cells (h) treated by erdafitinib with or without HDGF knockdown. Cells were treated by erdafitinib for 3 days. And cell viabilities were determined by WST-1 assay and normalized to DMSO control for each cell line. Data were plotted as mean ± standard deviation from three biological replicates and statistics were calculated by one-way ANOVA (**p < 0.01; ****p < 0.0001). siControl, siRNA of non-targeting control. 10/25/50E, 10/25/50 nM erdafitinib; 50Q, 50 nM quisinostat.