Table 2.

The effects of reversal agents in KB-3-1 and KB/ATO cells to the cytotoxicity of ATO.

Treatment	IC50 value±SDa (μmol/L)		Resistant Foldb
	KB-3-1	KB/ATO
ATO	3.71 ± 2.89	26.24 ± 8.77	7.07*
+ Verapamil 5 μmol/L	1.95 ± 1.33	7.45 ± 5.09	3.82
+ Sildenafil 5 μmol/L	5.77 ± 5.23	26.72 ± 9.23	4.63*
+ Sipholenol A 5 μmol/L	3.31 ± 2.22	16.32 ± 10.29	4.93
+ PAK-104P 5 μmol/L	2.44 ± 2.13	6.34 ± 5.24	2.59
+ ONO-1078 5 μmol/L	3.69 ± 3.13	27.13 ± 5.12	7.35*
+ FTC 5 μmol/L	4.28 ± 1.72	26.43 ± 4.33	6.18*

^*P < 0.05 versus parental cells.

^aIC₅₀ values are represented as mean ± SD of three independent experiments performed in triplicate.

^bResistance fold was calculated by dividing the IC₅₀ values of KB/ATO cells by the IC₅₀ of KB-3-1 cells after treatment.