Figure 2.

H₂O₂ production rate for whole and permeabilized melanoma cells at basal and PLB induced levels. A375 and SK-MEL-28 cells were counted and placed in the Oroboros respiratory chambers, with sequential injections of Cx I and Cx II substrates (① L-glutamate; ② L-malic; ③ ADP; ④ pyruvate; ⑤ succinate), Digi (8.1 mM), Oligo (5 mM), FCCP (1 mM), ROT (1 mM), and AA (5 mM). H₂O₂ signals were detected by Amplex UltraRed. (a) The H₂O₂ level (black line) and H₂O₂ flow for per million A375 and SK-MEL-28 cells (green line) were monitored in real-time. The red dashed box, along with a red arrow, highlights the H₂O₂ production drop in A375 cells compared to SK-MEL-28 cells. (b) The stable H₂O₂ flow values for per million A375 and SK-MEL-28 cells are displayed in the bar graph. (n = 3) The H₂O₂ production rates for whole and permeabilized (c) A375 cells and (d) SK-MEL-28 cells with DMSO and 1 and 3 µM PLB treatments are represented as the H₂O₂ flow before and after digitonin is applied (n = 3). Results are expressed as mean ± SD. * p < 0.05, ** p < 0.01. DMSO, dimethyl sulfoxide; PLB, plumbagin.