TABLE 1.

Doxorubicin sensitivity of MCF7-derived cell lines used in this study

AUC was derived from fraction cell survival-doxorubicin concentration plots in Fig. 3, C and D. IC₅₀ and IC₉₀ values derived from four-parameter logistic nonlinear regression curve fit presented in Fig. 3, A and B.

Cell Line	AUC	IC50	95% CI	IC90	95% CI
	nM	nM		nM
WT scrambled	162a	11.7	10.90–12.52	2.16	1.81–2.58
WT CK2A(−)	155a	10.6	9.459–11.90	1.46	1.08–1.98
MRP1 scramble	360a	88.6b	79.23–98.97	5.45b	3.99–7.46
MRP1 CK2A(−)	229a	24.9b,c	21.55–28.73	1.31c	0.9036–1.885
WT	564	12.2	10.98–13.47	2.45	1.9–3.16
MRP1	1114	105.3d	97.85–113.3	12.93d	10.68–15.67
MRP1-T249A	961	101.7d	87.53–118.2	5.58d,e	3.76–8.28
MRP1-T249E	1514	107.7d	94.61–122.6	11.67d	0.39–16.22

CI, confidence interval.

^a AUC calculated only for data points between 0 and 1 μM to allow for comparison between the lines.

^b Significantly different from WT scrambled control.

^c Significantly different from MRP1 scrambled.

^d Significantly different from WT control.

^e Significantly different from MRP1.