Fig. 2
Biguanide inhibition of rotenone-sensitive respiration in intact cells. Panels a–c show the progression of rotenone-sensitive oxygen consumption rates (OCRs) in 143B (a), HepG2 (b), and MDBK (c) cells following addition of biguanides. The traces are the means ± standard deviation (SD) of multiple traces. For 143B, n = 9 for control and proguanil; n = 11 for phenformin and compounds 2 and 5; and n =12 for compounds 1, 3, and 4. For HEP G2, n = 9 for control and proguanil; n = 11 for phenformin and compounds 2 and 3; and n = 12 for compounds 1, 4, and 5. For MDBK, n = 8 for control; n = 7 for compounds 1 and 5; and n = 6 for phenformin, proguanil, and compounds 2, 3, and 4. Biguanide concentrations were set to IC50/10: 34 μM phenformin; 40 μM compound 1, 42 μM compound 2; 97 μM compound 3; 2.88 mM compound 4; 32 μM compound 5; and 2 μM proguanil. d Rotenone-sensitive OCRs in 143B (black), HepG2 (gray), and MDBK (white) cells after 6 h of biguanide incubation (% of the control, error bars show propagated SD). Individual data points for panel d are provided in Additional file 1. con. control, phenf. phenformin, prog. proguanil