fig4

Figure 4. RCC1 knockdown sensitizes drug-resistant CRC cells to chemotherapy. (A) Cell cycle distribution in 5-FU- and Doxo-resistant HCT116 cells assessed by flow cytometry after 48-h treatment with 38.43 µM 5-FU or 800 nM Doxo, with or without RCC1 knockdown; (B) Statistical analysis of cell cycle phase proportions (one-way ANOVA); (C) Apoptosis in 5-FU- and Doxo-resistant HCT116 cells after 48-h treatment with 38.43 µM 5-FU or 800 nM Doxo, with or without RCC1 knockdown; (D) Statistical analysis of apoptotic cell populations (two-way ANOVA); (E) Cell viability (CCK-8 assay) of 5-FU- and Doxo-resistant HCT116 cells after 48-h treatment with various drug concentrations, with or without RCC1 knockdown (two-way ANOVA); (F) Tumor spheroid disruption assessed in drug-resistant HCT116 cells after 5-day treatment with 153.7 µM 5-FU or 2,000 nM Doxo; (G) Western blot analysis of cell cycle-related proteins after treatment with 38.43 µM 5-FU. GAPDH was used as the loading control; (H) Western blot analysis of cell cycle- and apoptosis-related proteins following treatment with 800 nM Doxo. β-actin served as the loading control. ns, not significant; ^***P < 0.001; ^**P < 0.01; ^*P < 0.05. RCC1: Regulator of chromosome condensation 1; CRC: colorectal cancer; 5-FU: 5-fluorouracil; Doxo: doxorubicin; ANOVA: analysis of variance; GAPDH: glyceraldehyde-3-phosphate dehydrogenase.