SIRT1 and cancer: In contrast, although SIRT1 has been known to stimulate muscle regeneration, in our investigation, SIRT1 was significantly increased in cancer cachexia, whereas its level was significantly decreased in the group treated with NR (p < 0.001, Figure 3C), reflecting the fact that the elevation of SIRT1 might be due to compensatory mechanism against muscle atrophy (Toledo et al., 2011).