Fig. 6

Apoptosis induced by MitoVES is dependent on complex II. (A) Adherent and sphere MCF7 cells were transfected with non-silencing (NS) and SDHC shRNA and assessed for the level of SDHA and SDHC by qPCR and WB with actin as loading control. The graphs on the right show the level of the SDHA and SDHC proteins in the sub-lines related to actin. (B) Parental and SDHC^low MCF7 cells were grown in serum-containing and ‘sphere’ medium and inspected by light microscopy. Parental and SDHC^low MCF7 sphere cells were evaluated for SDH and SQR activities (C) and for the level of stemness genes related to their level in MCF7 adherent cells set as 1 (D). MCF7 sphere cells were exposed to MitoVES homologues at 5 μM for 1 h and assessed for ROS using MitoSOX (E) and for 12 h and assessed for apoptosis (F). Parental, NS and SDHC^low MCF7 sphere cells, as shown, were exposed to MitoVES for 24 h (viability) or 12 h (apoptosis) and evaluated for viability using the MTT assay (G) and apoptosis by the annexin V/PI method (H). (I) Adherent and sphere MCF7 cells were evaluated for apoptosis after 24 h exposure to 5 μM MitoVES in the absence or presence of 10 μM TTFA. Data are mean values ± S.D. (n = 3). The symbol ‘*’ in panels A-C indicates statistically significant differences for parental and SDHC^low MCF7 cells, in panel D for adherent and sphere cells, in panels E and F for control and treated cells, in panels G and H for parental and SDHC^low MCF7 cells, and in panel I for cells treated in the absence and presence of TTFA, with p < 0.05. Images in panel B are representative of three independent experiments