Figure 6. Inhibition of mitochondrial respiration and hypoxic responses by treatment with antitumor compounds.

a, b. OCR of HT-29 Pt cells treated with the indicated concentrations of metformin (a) or arctigenin (b). Rotenone (RTN, 200 nM) was used as a positive control of OCR inhibition. c. HRE-luc activity of HT-29 Pt cells after 18 hours of hypoxia (Hyp) or normoxia (Nor), treated with the indicated concentrations of metformin or arctigenin. Cells treated with rotenone (RTN, 100 nM), antimycin A (ANT, 5 ng/ml) or oligomycin (OLG, 5 μg/ml); HT-29 ρ⁰n cells were used as positive controls. d. Immunoblot analysis of HIF-1α in HT-29 Pt cells treated with metformin (M, 3mM) or arctigenin (A, 10 μM) after 18 hours of hypoxia (Hyp) or normoxia (Nor). mTOR was used as a loading control.