The fact that CB1 receptor antagonism (using Rimonabant) does not interfere with the protective effects of ART27.13 suggests ART27.13 is not acting via the CB1R. By contrast, the addition of a CB2 receptor antagonist (AM630) inhibited the ability of ART27.13 to protect against the deleterious effects of cancer CM on human myotubes, indicating that ART27.13 acts via the CB2R. The gene discussed is CNR1; the disease is cancer.