Figure 1.

5-FU contributes to induced ER stress and enhanced drug resistance in BC cells. A. The GRP78 expression induced by 5-FU treatment in MCF-7 cells measured by Western blot analysis. B. The expression of ER stress-related proteins in MCF-7 and MDA-MB-468 cells after treatment with 5-FU for 24 h determined by Western blot analysis. C. The transfection efficiency of si-GRP78-1 and si-GRP78-2 in 5-FU-treated MCF-7 cells measured by Western blot assay. D. Viability of MCF-7 cells exposed to different concentration of 5-FU after knockdown of GRP78 by CCK8 assay. E. The transfection efficiency of oe-GRP78 in 5-FU-treated MCF-7 cells measured by Western blot assay. F. Viability of MCF-7/5-FU and MCF-7 cells exposed to different concentration of 5-FU measured by CCK8 assay. G. The protein expression of GRP78 in the MCF-7/5-FU and MCF-7 cells measured by Western blot analysis. *P<0.05 vs. the PBS group or MCF-7 cells. Measurement data were expressed as mean ± standard deviation. Data in compliance with normal distribution and homogeneity between two groups were compared using t-test. Comparisons among multiple groups were conducted by one-way ANOVA with Tukey’s post-hoc test. Statistical analysis in relation to time-based measurements within each group was realized using repeated measures ANOVA, followed by a Bonferroni’s post-hoc test for multiple comparisons. The experiment was repeated three times.