Liver protein synthesis stays elevated after chemotherapy in tumour-bearing mice

Abstract

We studied the effect of chemotherapy on liver protein synthesis in mice bearing colon 26 adenocarcinoma (C26). Liver protein mass decreased (−32%; P<0.05) in cachectic mice, but protein synthesis increased (20–35%; P<0.05) in cachectic mice, which is consistent with increased export protein synthesis. Increased protein synthesis in tumour-bearing mice was primarily mediated by increasing (∼15%; P<0.05) the RNA concentration, i.e. the capacity for protein synthesis (Cs; mg RNA/g protein). Cystemustine, a nitrosourea chemotherapy that cures C26 with 100% efficacy, rapidly restored liver protein mass; protein synthesis however stayed higher than in healthy mice (∼15%) throughout the initial and later stages of recovery. Chemotherapy had no significant effect on liver protein mass and synthesis in healthy mice. Reduced food intake was not a factor in this model. These data suggest a high priority for liver protein synthesis during cancer cachexia and recovery.