Fig. 5.

Mutation-induced sensitization to mitoxantrone toxicity of the growth of multidrug-resistant cells. The different sensitivities to mitoxantrone of transfected HEK293 cells with stable expression of wild-type ABCG2 (in green) or the control pcDNA3.1 empty vector (in magenta) were compared to that of ABCG2 mutants (in black) with the following point mutations: L352A (a), S353A (b), G354A (c) or E356A (d). The cells were cultured on monolayer at day 0, and increasing concentrations of mitoxantrone were added to cells at day 1 until day 5; they were stained with MTT, and the absorbance read at 570 nm. Data points represent mean values ±SD (n = 3)