Cell surface display, functional activity, and relative mRNA levels for Pgp and MRP in human CD33+ hematopoietic cell lines
. | Cell surface staining intensity ratio . | . | . | Dye efflux inhibitor-modulating factor . | . | Relative normalized mRNA level . | . | . | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cell line . | Pgp . | MRP1 . | MRP2 . | Pgp . | MRP . | Pgp . | MRP1 . | MRP2 . | |||||
| HL-60 | 0.96 ± 0.03 (7) | 1.17 ± 0.04 (15) | 1.30 ± 0.05 (8) | 1.01 ± 0.00 (9) | 1.85 ± 0.19 (10) | < 0.001 | 0.15 | 0.98 | |||||
| NB4 | 0.96 ± 0.01 (5) | 1.16 ± 0.03 (5) | 1.19 ± 0.12 (2) | 1.01 ± 0.00 (3) | 1.23 ± 0.04 (3) | < 0.001 | 0.15 | 1.18 | |||||
| TF1 | 1.21 ± 0.11 (6) | 1.17 ± 0.04 (7) | 1.17 ± 0.03 (3) | 1.43 ± 0.19 (4) | 2.90 ± 0.74 (4) | 1.00 | 1.00 | 1.00 | |||||
| HL-60/AR | 0.95 ± 0.05 (6) | 1.43 ± 0.10 (6) | 1.23 ± 0.06 (3) | 1.02 ± 0.00 (4) | 2.39 ± 0.28 (4) | 0.006 | 3.30 | 0.53 | |||||
| HL-60/VCR | 1.75 ± 0.08 (4) | 1.17 ± 0.03 (5) | 1.26 ± 0.03 (2) | 4.51 ± 0.23 (3) | 1.80 ± 0.23 (4) | 38.8 | 0.10 | 0.31 | |||||
. | Cell surface staining intensity ratio . | . | . | Dye efflux inhibitor-modulating factor . | . | Relative normalized mRNA level . | . | . | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cell line . | Pgp . | MRP1 . | MRP2 . | Pgp . | MRP . | Pgp . | MRP1 . | MRP2 . | |||||
| HL-60 | 0.96 ± 0.03 (7) | 1.17 ± 0.04 (15) | 1.30 ± 0.05 (8) | 1.01 ± 0.00 (9) | 1.85 ± 0.19 (10) | < 0.001 | 0.15 | 0.98 | |||||
| NB4 | 0.96 ± 0.01 (5) | 1.16 ± 0.03 (5) | 1.19 ± 0.12 (2) | 1.01 ± 0.00 (3) | 1.23 ± 0.04 (3) | < 0.001 | 0.15 | 1.18 | |||||
| TF1 | 1.21 ± 0.11 (6) | 1.17 ± 0.04 (7) | 1.17 ± 0.03 (3) | 1.43 ± 0.19 (4) | 2.90 ± 0.74 (4) | 1.00 | 1.00 | 1.00 | |||||
| HL-60/AR | 0.95 ± 0.05 (6) | 1.43 ± 0.10 (6) | 1.23 ± 0.06 (3) | 1.02 ± 0.00 (4) | 2.39 ± 0.28 (4) | 0.006 | 3.30 | 0.53 | |||||
| HL-60/VCR | 1.75 ± 0.08 (4) | 1.17 ± 0.03 (5) | 1.26 ± 0.03 (2) | 4.51 ± 0.23 (3) | 1.80 ± 0.23 (4) | 38.8 | 0.10 | 0.31 | |||||
Values represent mean ± SD of the cell surface staining intensity ratio (MFI of cells stained with specific antibodies divided by the MFI of cells stained with an isotype control antibody). Numbers in parentheses represent numbers of independent experiments.
Pgp activity was determined by the efflux of the fluorescent dye DiOC2 with or without the inhibitor CSA. MRP activity was determined by the efflux of CDCF with or without the inhibitor MK-571. Results are expressed as inhibitor-modulating factor (ratio of the MFI in the presence of the inhibitor divided by the MFI in the absence of the inhibitor).
Relative normalized mRNA levels were determined using real-time RT-PCR, and results of one representative experiment are shown. Results are expressed as the transcript levels of Pgp, MRP1, or MRP2 divided by the β2-microglobulin transcript level. Normalized ratios for TF1 transcript levels were arbitrarily set at 1 because that cell line constitutively expresses all 3 transporters. TF1 RNA was used to generate standard curves for each experiment (“Patients, materials, and methods”).