Fig. 3.

Relationship of mitochondrial oxidant stress to myofiber size and chemotherapy administration. A–C: relationship of myosin heavy chain (MHC) I and II cross-sectional area (CSA) to peroxiredoxin 3 (Prx 3) expression and relationship of MHC II CSA to oxidized Prx 3 in breast cancer patients (■). In A, r value is Pearson’s coefficient; in B and C, r values are Spearman’s rank coefficients. For A and B, n = 9; for C, n = 11. AU, arbitrary units. D and E: effects of 3 days of doxorubicin (Dox, 0.2 µM) or paclitaxel (Taxol, 40 nM) treatment vs. control [Ctrl (DMSO)] on C2C12 myotube Prx 3 expression (D, n = 4/condition) and oxidation, with the latter being shown by Prx 3 dimers [oxidized (ox)] under nonreducing conditions (E). F: quantitation of oxidized Prx 3 (n = 4/condition). Data in D and F are means ± SE, with individual data points shown with each bar. For A–C, multiple observations for CSA within each individual were averaged to provide a single data point for each individual. For D, immunoblots are shown above average data with loading control (GAPDH). Loading controls are not shown for E, as oxidized Prx 3 data are expressed as a fraction of total (oxidized + nonoxidized) Prx 3. *P < 0.05 vs. Ctrl.