Figure 2.

Co-application of 2-APB with doxorubicin leads to facilitated entry of doxorubicin into mouse BNL1 ME cells. (A) Representative epifluorescent images of cultured BNL1 ME cells, 5 min after application 1 µM doxorubicin alone (left) and co-application of 200 μM 2-APB with 1 µM doxorubicin (right). Note that doxorubicin-based fluorescence (see Methods) was detected only when co-applied with 2-APB. (B) Bar graph depicting means ± SEM of changes in intensity of intracellular fluorescence following application of vehicle, 2-APB alone, doxorubicin alone, or doxorubicin together with 2-APB at the indicated concentrations. The values for vehicle and 2-APB alone were measured 30 min after application. 2-APB was then washed out for 30 min, and the values for doxorubicin alone or doxorubicin together with 2-APB were measured after 60 min each. Note that doxorubicin-based intracellular fluorescence was above the noise levels (0.05 F/F₀) only after the co-application of doxorubicin with 2-APB. ***p < 0.001, compared to doxorubicin alone, paired t-test, ns, not significant, n = 60 cells, three repetitions.