TABLE 1

Protein expression of BCRP in membrane extracts and corrected ERs of dantrolene, coumestrol, daidzein, and genistein across MDCKII monolayers transduced with varying titers of BacMam2-BCRP viruses

Protein Level of BCRP^{^a}	Corrected ER^{^b}
Protein Level of BCRP^{^a}	Dantrolene	Coumestrol	Daidzein	Genistein
fmol/µg⋅protein
0	0.63 ± 0.22	1.09 ± 0.58	0.80 ± 0.10	0.52^{^c}
3.47	1.09 ± 0.15	3.00^{^c}	1.86 ± 0.36	1.32 ± 0.32
13.4	2.62 ± 0.31	3.99 ± 1.17	5.95 ± 0.61	1.59 ± 0.75
34.4	3.56 ± 0.77	7.67 ± 1.86	10.9 ± 3.0	7.21 ± 3.86
60.6	6.39 ± 1.59	10.7 ± 2.4	10.5 ± 6.3	8.09^{^c}
50.1^{^d}	7.24 ± 0.75	18.6 ± 4.0	18.4 ± 2.3	10.0 ± 2.2

↵^a Protein levels are the mean value of duplicate measurements.
↵^b Data are presented as the mean ± S.D. from three individual transwell assays unless otherwise indicated.
↵^c The corrected ER was calculated from the permeability with at least one averaged from two individual transwell assays.
↵^d The MDCKII cells were transduced with the highest titers of BacMam2-BCRP. The protein level of BCRP from the membrane extract was likely underestimated since these cells had the highest mRNA level (assayed by quantitative polymerase chain reaction) and BCRP efflux activity. These cells also had the highest protein level of BCRP when assayed by the LC-MS/MS technique with another different surrogate peptide (ATEIIEPSK).