SLC9A1 and breast cancer: To pharmacologically determine the importance of the individual transporters in 3D growth of breast cancer cells, MCF-7 cells were grown as 3D spheroids for two days, followed by seven days of growth in the presence of cariporide (10 μM), S0859 (50 μM), and/or AR-C155858 (20 μM) to inhibit NHE1, NBCs, or MCT1/2, respectively (Fig. 4).