Figure 3: Drug efflux assay showing the upregulation of ABCG2-mediated drug efflux in HCT-116, S1 and S1M1-80 cells after a 16 h pretreatment with 2-DG (20 mM) or hypoxia. ΔMFI was determined as the difference in mean fluorescence intensity between the FTC/efflux and efflux histograms, which indicates the ABCG2-mediated transport activity. 𝑃 < 0 . 0 5 , significantly different from the untreated HCT-116, S1, S1M1-80 cells, respectively.