Fig. 2From: Enhanced efficacy of photodynamic therapy by inhibiting ABCG2 in colon cancersDifferences of PDT effect between SW480 and HT29 cells depending on ABCG2 expression level. a, SW480 and HT29 cells were irradiated with a PDT laser (4 J/cm2) after a 16 h pretreatment of PPa at indicated concentrations. The MTT assay was performed in triplicate 24 h following the irradiation. b, Cells were incubated with 100 nM PPa for 16 h and then lysed with methanol, followed by application of PMT-based singlet oxygen monitoring system. c, Cells were incubated with 200 nM PPa for 16 h and then subjected to immunocytochemical staining for anti-abcg2 (Green), PPa (Red), and DAPI (blue). Data are means ± SEM from three independent experiments (*P < 0.05, **P < 0.01, #P < 0.0001)Back to article page