Figure 1: Influence of oxygen and dimethyloxaloylglycine (DMOG) on cell viability in MCF-7 and MDA-MB-231 breast adenocarcinoma cell lines, as determined by MTT assay. Note: (A) When compared to medical air, which was used as a control (21% (v/v) O2), exposure to 30%, 60% or 80% (v/v) O2 for 3 hours did not significantly affect viability of either MDA-MB-231 or MCF-7 cells, measured after 24 hours (n = 3). (B) Acute exposure to the hypoxia mimetic agent DMOG also had no effect on viability. Viability of cells exposed to medical air or 60% O2 with dimethyloxaloylglycine (DMOG) for 3 hours was compared to cells exposed to medical air or 60% O2 in the presence of the DMOG vehicle (water) alone, with viability being assessed at 24 hours (n = 3). Values shown are mean (SEM) versus values for matched cells exposed to control gas at the same time. (C, D) Representative image of MTT assay for cells exposed to medical air (C) or to 60% O2 (D).