Table 1.

Selonsertib sensitized ABCB1-substrate-selected resistant cell lines to ABCB1 substrates.

Treatment	IC50 ± SDa (RFb)
	KB-3–1 (μM)	KB-C2 (μM)	SW620 (μM)	SW620/Ad300 (μΜ)
Doxorubicin	0.034 ± 0.004 (1.00)	4.792 ± 0.809 (142.01)	0.052 ± 0.011 (1.00)	2.487 ± 0.785 (47.91)
+Selonsertib (3 μM)	0.032 ± 0.002 (0.96)	3.332 ± 0.616 (98.74)	0.040 ± 0.002 (0.76)	1.731 ± 0.103 (33.35)
+Selonsertib (10 μM)	0.029 ± 0.002 (0.87)	0.368 ± 0.077 (10.91)*	0.055 ± 0.012 (1.07)	0.367 ± 0.017 (7.07)*
+Verapamil (10 μM)	0.020 ± 0.004 (0.60)	0.166 ± 0.042 (4.91)*	0.044 ± 0.013 (0.84)	0.214 ± 0.044 (4.12)*
Paclitaxel	0.004 ± 0.002 (1.00)	3.007 ± 0.546 (799.31)	0.026 ± 0.001 (1.00)	1.587 ± 0.418 (60.44)
+Selonsertib (3 μM)	0.003 ± 0.001 (0.82)	2.291 ± 0.369 (609.04)	0.023 ± 0.003 (0.88)	1.059 ± 0.008 (40.34)
+Selonsertib (10 μM)	0.003 ± 0.001 (0.70)	0.125 ± 0.095 (33.23)*	0.030 ± 0.002 (1.15)	0.219 ± 0.174 (8.34)*
+Verapamil (10 μM)	0.003 ± 0.002 (0.78)	0.091 ± 0.004 (24.07)*	0.021 ± 0.010 (0.78)	0.092 ± 0.061 (3.51)*
Cisplatin	1.381 ± 0.776 (1.00)	2.267 ± 1.461 (1.64)	1.159 ± 0.038 (1.00)	1.303 ± 0.083 (1.12)
+Selonsertib (3 μM)	1.734 ± 1.280 (1.26)	2.405 ± 1.790 (1.74)	1.134 ± 0.105 (0.98)	1.588 ± 0.067 (1.37)
+Selonsertib (10 μM)	1.917 ± 1.242 (1.39)	2.546 ± 1.941 (1.84)	1.488 ± 0.047 (1.28)	1.140 ± 0.059 (0.98)
+Verapamil (10 μM)	1.462 ± 0.681 (1.06)	2.376 ± 1.846 (1.72)	1.108 ± 0.031 (0.96)	1.160 ± 0.176 (1.00)

^*indicates p < 0.05 versus group treated with antineoplastic drug only.

^aIC₅₀ values were determined by MTT assay as described in “materials and methods”, and were obtained from three independent experiments in triplicate.

^bResistance fold (RF) was calculated from dividing the IC₅₀ values of parental cells or resistant cells by the IC₅₀ of parental cells in the absence of selonsertib or positive control inhibitor.