Fig. 7
Inhibition of intracellular carbonic anhydrases lowers the capacity for cellular net acid extrusion in murine ErbB2-induced breast cancer tissue. A Average curves of pHi in freshly isolated breast cancer organoids during NH4+-prepulse-induced intracellular acidification and subsequent recovery (n = 6). Experiments were performed with acetazolamide (ATZ, 100 µM), 4-(aminoethyl)benzenesulfonamide (AMB, 30 µM), or equivalent volume of DMSO vehicle. The right part of the panel shows the recovery phase from intracellular acidification magnified. B Net acid extrusion plotted as function of pHi for peripheral and core regions of organoids (cf. Figure 6C) freshly isolated from ErbB2-induced murine breast cancer tissue (n = 6). C Net acid extrusion calculated at a fixed pHi corresponding to the initial pHi recovery phase during maximal acidification (n = 6). The values refer to the phase after Na+ was added to the bath to activate Na+-dependent transport mechanisms. Data were compared by repeated-measures two-way ANOVA followed by Dunnett’s post-tests. *P < 0.05, NS: not significantly different vs. vehicle