Role of drug transporters and drug accumulation in the temporal acquisition of drug resistance

BMC Cancer

Table 1 Concentrations of chemotherapy drugs used at each selection dose

Dose	Doxorubicin	Epirubicin	Paclitaxel	Docetaxel
IC₅₀	8.91 nM	4.79 nM	0.56 nM	0.51 nM
1	8.91 pM	4.79 pM	0.56 pM	0.51 pM
2	26.7 pM	14.4 pM	1.67 pM	1.52 pM
3	80.1 pM	43.2 pM	5.01 pM	4.56 pM
4	240 pM	130 pM	15.0 pM	13.7 pM
5	720 pM	390 pM	45.0 pM	41.1 pM
6	2.16 nM	1.17 nM	135 pM	123 pM
7	6.48 nM	3.51 nM	405 pM	369 pM
8	19.4 nM	10.5 nM	1.22 nM	1.11 nM
9	29.1 nM	31.5 nM	3.66 nM	3.33 nM
10	43.6 nM	94.5 nM	11.0 nM	5.00 nM
11	65.4 nM	284 nM	33.0 nM	15.0 nM
12	98.1 nM*	852 nM	99.0 nM	45.0 nM*

MCF-7 breast tumour cells were exposed to progressively higher concentrations (doses) of chemotherapy drugs, beginning at a dose equivalent to 1/1000^th of the concentration required to kill or inhibit the growth of 50% of wild-type MCF-7 cells (the IC₅₀). The symbol * denotes the highest concentration of drug at which the cells could survive (the maximally tolerated dose).

ISSN: 1471-2407