Figure 5

Direct effects of IA on mitochondrial respiratory states of MCF7 and MDA-MB-231 are different. Oxygen level traces (insets) and OCR traces in the absence and presence of 20 mM IA added on saponin-permeabilized cells (4 million cells) measured by Oroboros O2k Oxygraph for both MDA-MB-231 (A) and MCF7 (B). Different substrates/inhibitors combinations were sequentially added to obtain standard respiratory parameters pertaining to different electron transport chain complexes in the two cell lines. NADH- and succinate-linked respirations were found to be highly sensitive to complex I inhibition by rotenone and complex III inhibition by antimycin A only in MDA-MB-231 cells (C). While basal respiration was higher in MCF7 cells (D), complex I- and complex II- mediated respiration were significantly higher in MDA-MB-231 cells. (E,F) IA at 20 mM didn’t completely abolish respiratory activities in MDA-MB-231 cells and didn’t affect respiratory activities in MCF7. Quantification was carried out over three independent runs. Statistical analyses were carried out using paired t test where statistical significance was achieved at p < 0.05.