XPO1 inhibition overcame acquired resistance to CYH33. a The proliferation of indicated cells treated with CYH33 was evaluated with an SRB assay. b Gene sets that were enriched in MCF7R cells compared to those in parental cells, as analyzed with GSEA. c GI50 of the indicated inhibitors in MCF7R and parental cells; the mean of two independent experiments is shown. The p value was calculated by a Student’s t test. *p < 0.05. d Cells were treated with the indicated XPO1 inhibitors, and the GI50 was evaluated. e Gene sets that were enriched in MCF7R cells treated with KPT-330 compared to those in cells treated with DMSO, as analyzed with GSEA. f Cells were treated with KPT-330 (1 μM) for 24 h and were processed for an immunofluorescence assay with an antibody against p53. g MCF7R cells were treated with the indicated inhibitors for 72 h, and cell proliferation was measured. K: KPT-330; C: CYH33. Data shown are the mean ± SD or representative of three independent experiments.