Figure 4

Evaluation of selected ABC transporter expression in lung carcinoma COR-L23 (parental and resistant) cell lines. A) The fold change in expression in COR-L23R cells compared to the parental cell line is depicted for the gene expression of ABC transporters. Two individual determinations of crossing point values are given. B) Western blotting with MRPr1 antibody (1:1000) shows that only COR-L23R cell lysates express ABCC1[27]. Lane 1, 20 μg of COR-L23P; lane 2, 10 μg of COR-L23R; and lane 3, 20 μg of COR-L23R. C) C219 (1:1000) was used to detect ABCB1[28]. Lane 1, COR-L23P (100,000 cells); lane 2, COR-L23R (100,000 cells); and lane 3, positive control, KB-A1 (100,000 cells). D) ABCG2 was detected with BXP-21 (1:1000)[29]. Lane 1, COR-L23P (100,000 cells); lane 2, COR-L23R (100,000 cells); and lane 3, positive control, MCF-7-FL1000 (100,000 cells). E) Functional ABCC1 is expressed in COR-L23R cells as determined by calcein-AM efflux assays. Brown solid line histogram, COR-L23P; blue solid line histogram, COR-L23P with 20 μM MK-571; red solid line histogram, COR-L23R control; and green solid line histogram, COR-L23R with 20 μM MK-571. The results from a typical experiment are shown in the panel. Similar results were obtained on two additional experiments.