Fig. 7.

TNBC cells exhibiting a hybrid metabolic phenotype that requires treatment with both glycolytic and OXPHOS inhibitors. (A) Seahorse XF analysis suggesting that the metastatic TNBC cells MDA-MB-231 and SUM159-PT exhibit a hybrid metabolic phenotype. While addition of the respiratory inhibitor oligomycin decreased the mitochondrial respiration (OCR, solid lines), it immediately increased the glycolysis (ECAR, dotted lines). (B) Fold change in OCR and ECAR after FAO inhibitor ETX treatment in SUM159-PT cells. (C) Bifurcation diagram of pAMPK levels in response to inhibition of the glycolytic pathway (G2). ${\lambda }_{G,G_2}$ represents the strength of inhibition of G2. The smaller the ${\lambda }_{G,G_2}$, the stronger the inhibition. (D) Bifurcation diagram of HIF-1 levels in response to inhibition of ETC. ${\lambda }_{ETC}$ represents the strength of inhibition of ETC. The smaller the ${\lambda }_{ETC}$, the stronger the inhibition. More details to calculate D can be found in SI Appendix, section 5. (E) Western blotting analysis of AMPK and pAMPK after the cells were treated with 3BP for 24 h in high-glucose (4.5 g/L) or low-glucose (1 g/L) medium. (F) Cells were treated with the mitochondrial ETC complex I inhibitor rotenone (10 nM), the complex III inhibitor antimycin-A (10 μM), the complex V inhibitor oligomycin (5 μg/mL), or ETX (100 μM) for 24 h. Expression of glycolytic genes (GLUT1, LDHA, and c-Myc) was determined by qPCR. Glycolytic and OXPHOS inhibitors inhibited the cell proliferation (G) and the colony formation (H) in SUM159-PT and mouse metastatic basal BC 4T1 cells. Use of both glycolytic and OXPHOS inhibitors effectively eliminates the colony-formation potential of SUM159-PT and 4T1 cells. All data are presented as the means ± SE. *P < 0.05, **P < 0.01, ***P < 0.001 (two-tailed t test).