Figure 2.

Skeletal muscle cells undergo extensive metabolism changes after treated breast cancer-secreted exosomes. (A) Immunofluorescence staining for myosin heavy chain 1 (MYH1) after treatment 24 h. Scale bars represent 50 μm. The C2C12 in the CytoD group were treated with cytochalasin D (final concentration, 2 μg/ml) and 50 μg of exosomes purified from cancer-associated conditioned medium (CA-CM). (B) The levels of secreted metabolites (pyruvate and lactate) enriched in media were determined by colorimetric assay. (C) Raw data for the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) as determined by the Seahorse XF24 analyzer. The ECAR was evaluated after the addition of 10 mM glucose to C2C12 in the presence or absence of exosomes. The OCR was measured in the presence of palmitate as described in the Methods. (D) C2C12 were cocultivated in the presence or absence of exosomes. After 24 h, proteins were extracted for western blot analysis of the expression of the indicated proteins. The numbers represent the relatively quantitative results compared to the control group. Data are presented as the mean ± S.D. of at least three independent experiments. * P < 0.05 versus control values, # P < 0.05 versus control values as positive group.