Targeting the Lactate Transporter MCT1 in Endothelial Cells Inhibits Lactate-Induced HIF-1 Activation and Tumor Angiogenesis
Figure 5
Targeting MCT1 inhibits lactate-induced HIF-1 activation in normoxic endothelial cells.
(A) Relative mRNA expression was determined in confluent HUVECs using quantitative RT-PCR. n = 3. Error bars reflect mean ± SEM. (B) Immunostaining showing the membrane expression of MCT1 in HUVECs (upper panel) and negative control (lower panel, omission of primary antibody). Bar = 40 µm. (C) HUVECs transfected with the indicated siRNA were incubated during 24-h with 10 mM lactate or not. HIF-1α protein expression was detected by western blot. *p<0.05, ***p<0.005 compared to control; ###p<0.005 compared lactate alone; n = 6–14. (D and E) HIF-1α and VEGFR2 protein expression was detected by western blot. (D) HUVECs were incubated during 24-h with 10 mM lactate and/or 5 mM α-cyano-4-hydroxycinnamate (CHC). *p<0.05, **p<0.01, ***p<0.005 compared to control; ###p<0.005 compared to lactate alone; n = 3–12. (E) BAECs were incubated during 24-h with 10 mM lactate, 5 mM Nω-nitro-L-arginine methyl ester (L-NAME), 5 mM α-cyano-4-hydroxycinnamate (CHC), and/or 5 mM N-acetyl-L-cysteine (NAC). *p<0.01, ***p<0.005 compared to control; ###p<0.005 compared to lactate alone; n = 3–14. (C–E) Error bars reflect mean ± SEM.