Table 1

Effects of chemotherapeutic drugs on BCRP-transfected MCF-7 cells

DrugCell type
MCF-7/W MCF-7/pcDNA3 MCF-7/BCRPclone19 MCF-7/BCRP clone6 MCF-7/BCRP clone8 MCF-7/AdrVp
Median LC50, nM [Range, nM]NRFMedian LC50, nM [Range, nM]NRFMedian LC50, nM [Range, nM]NRFMedian LC50, nM [Range, nM]NRFMedian LC50, nM [Range, nM]NRFMedian LC50, nM [Range, nM]NRF
Mitoxantrone4171.04061.05411.3370*49.01,300*532160,00023,902
[20–105][15–115][—][130–700][280–3,600][120,000–200,000]
Daunorubicin4271.06851.65411.6180*44.3350*58.31,700341
[8–105][21–110][—][150–380][110–600][1,500–1,800]
Doxorubicin5651.04940.97041.3168*43.01,050*4198,6502155
[14–110][16–150][25–102][81–600][205–5,300][6,800–10,500]
Cisplatin2,60041.03,90031.56,90032.77,0003273,70031.52,87521.1
[1,600–4,000][3,000–4,050][4,700–6,900][3,080–13,000][3,500–13,000][1,050–4,700]
Paclitaxel1.941.05.122.70.930.51.931.03.031.61.941.0
[0.9–33][3–7.1][0.8–28][1.4–21][1.8–36][1.3–3.6]
Vincristine0.2631.00.3921.50.6332.40.3731.40.2831.10.933.5
[0.08–0.65][0.28–0.51][0.09–0.76][0.35–0.91][0.25–0.59][0.19–1.3]
  • Sensitivity of selected MCF-7 sublines to antineoplastic agents determined by sulforhodamine-B cytotoxicity assay (21). Experiments such as those displayed in Figure 4D were used to obtain the LC50. For each drug and cell type, the table displays the median LC50 and range of LC50 measurements (nM), the number of experimental determinations of LC50 that were performed (N), and the resistance factor (RF). The RF was calculated by dividing the median LC50 for a given drug against a transfected cell line by the median LC50 of that drug against nontransfected MCF-7/W cells. For each drug tested, the LC50 for the BCRP-transfected cells was examined for statistically significant difference from the LC50 of MCF-7/W or MCF-7/pcDNA3 by the Mann–Whitney test, using minitab statistical software minitab release 8 extended, Minitab, State College, PA) and a 95% confidence interval. The values of P for the statistically significant differences are as follows Mitoxantrone: MCF-7/W vs. MCF-7/BCRPclone6, P = 0.0107, MCF-7/W vs. MCF-7/BCRPclone8, P = 0.0058, MCF-7/pcDNA3 vs. MCF-71BCRPclone6, P = 0.0142, MCF-7/pcDNA3 vs. MCF-7/BCRPclone8, P = 0.0081; daunorubicin: MCF-7/W vs. MCF-7/BCRPclone6, P = 0.0107, MCF-7/W vs. MCF-7/BCRPclone8, P = 0.0058, MCF-7/pcDNA3 vs. MCF-7/BCRPclone6, P = 0.0195, MCF-7/pcDNA3 vs. MCF-7/BCRPclone8, P = 0.0163; doxorubicin: MCF-7/W vs. MCF-7/BCRPclone6, P = 0.0373, MCF-7/W vs. MCF-7/BCRPclone8, P = 0.02, MCF-7/pcDNA3 vs. MCF-7/BCRPclone8, P = 0.0304; cis-platin: MCF-7/W vs. MCF-7/BCRPclone19, P = 0.0497. 

  • * Differs significantly from MCF-7/W, P < 0.05 (Mann–Whitney test). 

  • Differs significantly from MCF-7/pcDNA3 (empty vector control, P < 0.05, Mann–Whitney U test).