Figure 3.

ABCG2-expressing drug-resistant cells have higher levels of autophagy following nutrient deprivation. (A) Autophagy flux was measured using a tandem-fluorescence-tagged LC3 assay. Parental and resistant H460 cell lines were transfected with a GFP-RFP-LC3 construct and treated with HBSS for 2 h. Cells were fixed and confocal images were taken. Quantification of the green and red dots is shown on the right. (B) Both MCF-7 and H460 cell pairs were incubated in HBSS alone or HBSS plus Baf A₁ for 2 h. LC3 II levels were analyzed using western blot and quantified (right). (C) Levels of SQSTM1 in parental cells and their resistant sublines were determined following treatment with HBSS with or without BafA₁ (20 nM). Quantifications are shown on the right.