The effect of AMPK on berberine sensitized DOX resistance and inhibited cell growth in MCF-7/hypoxia. (A) Cell viability in MCF-7/hypoxia cells after DOX combined with 5 μM berberine treatment, or DOX combined with 5 μM berberine and AICAR treatment for 48 h. Mean values ± SD, * P <0.05, MCF-7/hypoxia cells treated with DOX combined with 5 μM berberine for 48 h vs. MCF-7/hypoxia cells treated with DOX combined with 5 μM berberine and AICAR for 48 h. (B) Cell viability in MCF-7/hypoxia cells after berberine treatment or berberine and AICAR treatment for 48 h. * P <0.05, MCF-7/hypoxia cells treated with different concentrations of berberine for 48 h vs. MCF-7/hypoxia cells treated with different concentrations of berberine and AICAR for 48 h. (C) AMPK, HIF-1α, P-gp and p53 proteins expression after berberine treatment or berberine and AICAR treatment for 48 h in MCF-7/hypoxia cell. Each result was repeated three times.