Fig. 2

Establishment of GEM-R cells and assessment of chemosensitivity between WT and GEM-R cells in vitro. Note: GEM-R: gemcitabine-resistant MDA-MB-231 cells. Data are represented as mean ± SD. All experiments were performed in triplicate and repeated independently three times. In (C), cells were treated with 10 μM GEM for 72 h. A. Development of GEM-R cells by treating parental cells with gradient GEM (1 µM, 5 µM, 15 µM, 20 µM) after several cycles until stable proliferation. B. CCK8 assay was used to measure IC₅₀ of WT cells and GEM-R cells to gradient concentration of GEM. C. Percentage of cell apoptosis of WT cells and GEM-R cells was evaluated by detection of flow cytometry with Annexin-V FITC/PI Apoptosis Detection Kit. Flow cytometric: Annexin V-/P- represented normal cells; Annexin V-/P + represented necrotic cells; Annexin V + /P + represented late apoptotic cells; Annexin V + /P- represented early apoptotic cells