TABLE 2

IC₅₀ values for rhodamine123 efflux inhibition by verapamil, vinblastine, and propafenone analogs

IC₅₀ values were calculated from concentration response curves (shown in Figs 4–7). Results are represented as mean ± S.D. of at least three individual experiments performed in duplicate.

Mutation	IC₅₀
Mutation	Verapamil	Vinblastine	GPV31	GPV366
	μM
Wild-type P-gp	0.43 ± 0.10	2.68 ± 0.93	0.11 ± 0.06	2.60 ± 0.69
Q132A	0.30 ± 0.07	2.58 ± 0.31	0.10 ± 0.03	2.57 ± 0.69
Q773A	0.42 ± 0.15	2.80 ± 0.12	0.11 ± 0.05	2.40 ± 1.47
Q132A/Q773A	0.44 ± 0.16	2.24 ± 0.43	0.12 ± 0.01	2.87 ± 0.63
Q132R	1.24 ± 0.13^*	9.19 ± 1.20^*	0.71 ± 0.46^*	2.64 ± 0.59
Q773R	0.14 ± 0.04^*	0.45 ± 0.16^*	0.02 ± 0.01^*	2.09 ± 0.90

↵* P < 0.05, significantly different from wild-type values.