Figure 2

Knockdown of MCT1 induces apoptosis and reduces lactate incorporation. (A, B) MCT1 (A) and CD147 (B) mRNA expressions in KMM-1 cells were inhibited by siRNA transfection. The cells were treated with each siRNA and incubated for up to 5 days. Cell lysates harvested on each day were subjected to western blot analysis. Upper panel: siRNA-treated cells. Lower panel: control (untreated) cells. The siRNA-treated cells show significant reductions in MCT1 or CD147. (C) Lactate incorporation is inhibited by MCT1 inhibition. The siRNA-treated cells (KMM-1) were analyzed for lactate incorporation using ¹⁴C-lactate. To ensure the specificity of the analysis, cells were treated with radiolabeled lactate alone or combined with unlabeled lactate (cold lactate) simultaneously. Note that lactate incorporation is significantly inhibited by the siRNA for MCT1, but not by the siRNA for CD147.