Selective Inhibition of NF-kappa-B with NBD Peptide Reduces Tumor- Induced Wasting in a Murine Model of Cancer Cachexia In vivo

Abstract

Cancer cachexia is a severe wasting syndrome characterized by the progressive loss of lean body mass and systemic inflammation, which is seen in as many as 80% of patients with advanced malignancy. It accounts for an estimated 20-30% of all cancer-related deaths. The mechanism by which cancer induces skeletal muscle atrophy in cachexia involves tumor-derived cytokines, including TNF?, IL-1, and IL-6. Upon interaction with their unique receptors on skeletal muscle, these cytokines activate NF-kappaB, a transcription factor crucial for atrophy related sarcomere proteolysis to occur. The significance of NF-?B is highlighted in studies demonstrating that genetic inhibition of NF-?B ameliorates cancer-induced muscle loss in vivo. In the present study, we evaluate a selective NF-kappaB inhibitor (NBD peptide) which targets the IkappaB complex to prevent cancer-induced skeletal muscle atrophy in an established mouse model (C26 adenocarcinoma). We identified for the first time that NBD peptide can directly inhibit tumor-induced NFkappaB activation in skeletal muscle, resulting in a decrease loss of lean muscle. We also identified that NBD peptide reduces the expression of the tumor induced ubiquitin ligases MuRF-1 and MAFbx/Atrogin-1 necessary for atrophy. These findings highlight that NBD peptide may be a potential selective therapeutic agent for the treatment of cancer cachexia.