(A) C646, a specific pharmacological inhibitor of p300, abrogates the LCM-induced myotube catabolism. C2C12 myotubes were pre-treated (30 min) with pharmacological inhibitor of p300 (C646, 10 μM) or PCAF/GCN5 (CPTH6, 10 μM) prior to LCM exposure for 8 h. Markers of catabolic pathways were analyzed by Western blotting. (B) C646 abrogates the LCM-induced MHC loss. Myotubes were pre-treated with pharmacological inhibitor of p300 (C646) or PCAF/GCN5 (CPTH6) prior to LCM treatment for 72 h. The expression of MHC was analyzed by Western blotting. (C) C646 abrogates muscle catabolism in LLC tumor-bearing mice. Subcutaneous administration of C646 was initiated 7 days after the implantation of LLC. On day 21, mice were euthanized and analyzed for muscle catabolism markers by Western blotting. (D) C646 attenuates muscle mass loss in LLC tumor-bearing mice. (E) C646 attenuates body weight loss in LLC tumor-bearing mice. (F) C646 does not alter tumor growth. * p<0.05 signifies a statistically significant difference after One-way ANOVA analyses.