FIGURE 1.

ABCB8 effluxes DOX from cardiomyocytes. (A,B) H9C2 cells were treated with ABCB8 siRNA or plasmid DNA and DOX (10 µM) as described in the Methods section. ABCB8 protein expression was determined using western blot and normalized to α-tubulin levels. Discontinuities between non-adjacent lanes of the same membrane were indicated by a solid line. (C–E) ABCB8 KD and ABCB8 OE cells were incubated with DOX (30 µM) for 3 h and DOX fluorescence was measured at the indicated times. Results are representative of four independent experiments (C). DOX fluorescence was quantified over time (D). The area under the curve (AUC) was calculated (E) from the DOX retention plot (D). Data were expressed as mean ± SEM. Statistical significance was assessed using the Student’s t-test or ANOVA with Tukey’s post-hoc comparisons. *p < .05 vs. control. Scale bar = 10 µm.