In vitro cell uptake of 3-BPA and 4-BPA in cancer cells with various LAT1-expression. (a) The LAT1/β-actin ratio of each cell calculated from the expression levels of LAT1 and β-actin obtained by Western blotting and standardized to a value of 1 for T3M-4. (b,c) LAT1-specific accumulation (the difference in accumulation between the inhibitor group and the noninhibitor group) in T3M-4, A549, B16F10, and U-87MG cells after 1, 5, and 30 min incubation with 3-BPA (b) and 4-BPA (c). (d) The relationship between the uptake (% dose/mg protein) of 3-BPA and 4-BPA at 30 min incubation with a simple linear regression. Statistical analyses of LAT1-specific accumulation of 3-BPA (b) and 4-BPA (c) were shown in Supplementary Tables S3 and S4, respectively.