Figure 6

The bioenergetics defect of Sdhb knockdown cells can be exploited with metformin. (A) The oxygen consumption rate (OCR) was analyzed by the Seahorse XF24 Bioanalyzer in basal conditions and in response to sequential treatment with oligomycin (ATP synthase inhibitor), FCCP (dissipates mitochondrial membrane potential), and rotenone-myxothiazol (complex I inhibitor). (B, C) Cells grown in normal media were switched to media with or without glucose after 24 h. (B) After 48 h, cells were counted by trypan blue exclusion or (C) visualized by light microscopy. (D) The extracellular acidification rate (ECAR), an indicator of glycolysis, was analyzed by the Seahorse XF24 Bioanalyzer in basal conditions. (E) Mass spectrometry analysis of lactate and glucose in spent media of C1-scr and C1-sh1-Sdhb cells. Media was collected at 0 and 72 h. The y-axis depicts fold change of lactate secretion and glucose depletion relative to C1-scr cells. (F) Cells were treated with various concentrations of metformin for 3 days. Cells were visualized by crystal violet staining and extracted dye was quantified by a fluorescent plate reader.