Table 3.

Substrate-drugs of ABCB1 co-treated with WYE-354 decreased the survival rates of ABCB1-transfected cells.

Treatment	IC50 ± SD a (RF b) (μM)
	HEK293/pcDNA3.1	HEK293/ABCB1
Doxorubicin	0.022 ± 0.002 (1.00)	0.539 ± 0.054 (24.50)
+WYE-354 (0.3 µM)	0.023 ± 0.002 (1.04)	0.302 ± 0.077 (13.73) *
+WYE-354 (1 µM)	0.030 ± 0.001 (1.36)	0.157 ± 0.014 (7.14) *
+Verapamil (1 µM)	0.020 ± 0.004 (0.91)	0.034 ± 0.006 (1.54) *
Paclitaxel	0.051 ± 0.007 (1.00)	2.144 ± 0.245 (42.04)
+WYE-354 (0.3 µM)	0.082 ± 0.019 (1.61)	1.048 ± 0.087 (20.55) *
+WYE-354 (1 µM)	0.063 ± 0.016 (1.23)	0.549 ± 0.087 (10.76) *
+Verapamil (1 µM)	0.040 ± 0.013 (0.78)	0.091 ± 0.011 (1.78) *
Cisplatin	2.008 ± 0.055 (1.00)	1.990 ± 0.063 (0.99)
+WYE-354 (0.3 µM)	2.075 ± 0.106 (1.03)	1.686 ± 0.046 (0.84)
+WYE-354 (1 µM)	2.531 ± 0.111 (1.26)	1.907 ± 0.056 (0.95)
+Verapamil (1 µM)	2.375 ± 0.353 (1.18)	2.179 ± 0.037 (1.08)

^a IC₅₀ values are represented as mean ± SD from three independent experiments in triplicate. ^b The resistant fold (RF) was calculated by dividing the IC₅₀ values of the sensitive and resistance cells by the IC₅₀ of the HEK293/pcDNA3.1 cells without WYE-354 or verapamil. * indicates p < 0.05.