Research Article

Mitochondrial Complex I Inhibitors and Forced Oxidative Phosphorylation Synergize in Inducing Cancer Cell Death

Figure 4

The mitochondrial Complex I inhibitors piericidin A and capsaicin induce cell death in MDA-MB-231 cells as observed with rotenone. Viable cell count using Trypan Blue was performed after treatment with 5 nM piericidin A or 100  M capsaicin at 48 hours of culture in different growth conditions. (a)-(b) MDA-MB-231 cells were cultured in 25 mM glucose and counted after 2-hour treatment with piericidin A (a) or capsaicin (b). (c)-(d) MDA-MB-231 cells were cultured in 1 mM glucose and treated with (c) piericidin A or (d) capsaicin, 10  M FSK, or FSK together with Complex I inhibitors. In the last case, cells were pretreated with FSK for 1 hour and then piericidin A or capsaicin were added for 2 hours (see Figure 2(c) as example). After treatment cell count was performed. (e) After treatment with piericidin A cells were plated in normal growth medium for clonogenic assay and after ≥12 days colonies were stained and counted. (f) OCR of MDA-MB-231 cells cultured in low glucose was determined by Seahorse XF24 analyzer 30 minutes after injection of vehicle or 5 nM piericidin A; the percentage of OCR variation after injection is reported. All data represent the average of at least three independent experiments (±s.d.); , (Student’s   -test).
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