Figure 2. Inhibition of BMI1 overexpression reversed the chemoresistance in GC-resistant T24 cells. (A) Cell proliferation changes of T24 and T24/DDP&GEM cells assessed by cell counting kit-8 assays after treatment with 2 μg/ml DDP or 25 μg/ml GEM. (B) Apoptosis of T24 and T24/DDP&GEM cells detected by the Annexin V/flow cytometric apoptosis assay after treatment with 2 μg/ml DDP or 25 μg/ml GEM. (C) Western Blot analysis of BMI1 protein in T24 and T24/DDP&GEM cells. (D) Western Blot detection of BMI1 protein in T24/DDP&GEM cells upon BMI1 knockout using CRISPR/Cas9 system. (E) Cell proliferation changes of T24/DDP&GEM cells upon knockout of BMI1 were assessed by cell counting kit-8 assays after treatment with 2 μg/ml DDP. (F) Apoptosis of T24/DDP&GEM-sgBMI1 and T24/DDP&GEM cells detected by the Annexin V/flow cytometric apoptosis assay after treatment with 2 μg/ml DDP. (G) Under observation in inverted fluorescence microscope, the fluorescent intensity of dye in indicated cells after transfection with rhodamine 123. (H) The retention rate of rhodamine 123 dye in down-regulating BMI1 or vector control T24/DDP&GEM cells detected by flow cytometry. *P < 0.05. **P < 0.01. ***P < 0.001. GC: cisplatin and gemcitabine; DDP: cisplatin; GEM: gemcitabine.