Fig. 4

Decreased levels of miR-135b-5p correlated with up-regulation of AGR2 in breast cancer cells. a cDNA was synthesized from total RNA extracted from MDA-MB-231, MCF-7 and MCF-7/DOXR cells. qPCR was applied to measure levels of mature miRNAs with U6 as a normalization gene. b Correlation between levels of AGR2 mRNA and miRNAs were analyzed using Pearson correlation test. c-e MCF-7 and MDA-MB-231 cells were treated with gradient doses of doxorubicin for 48 h. Expression levels of AGR2 mRNA and miRNAs were measured by qPCR (n = 3). Experiment was repeated twice. Expression levels of RNAs represent fold changes. Data are shown as mean ± SD and are compared using unpaired t test or one-way ANOVA test. *, p < 0.05 compared with MDA-MB-231 cells; #, p < 0.05 compared with untreated cells. 0 nM represents untreated cells