An AMP-activated protein kinase-stabilizing peptide ameliorates adipose tissue wasting in cancer cachexia in mice
Rohm, M., Schafer, M., Laurent, V., Ustunel, B. E., Niopek, K., Algire, C., Hautzinger, O., Sijmonsma, T. P., Zota, A., Medrikova, D., Pellegata, N. S., Ryden, M., Kulyte, A., Dahlman, I., Arner, P., Petrovic, N., Cannon, B., Amri, E. Z., Kemp, B. E., Steinberg, G. R., Janovska, P., Kopecky, J., Wolfrum, C., Bluher, M., Berriel Diaz, M., and Herzig, S. (2016). Nat Med 22, 1120-1130. doi: 10.1038/nm.4171
Cachexia represents a fatal energy-wasting syndrome in a large number of patients with cancer that mostly results in a pathological loss of skeletal muscle and adipose tissue. Here we show that tumor cell exposure and tumor growth in mice triggered a futile energy-wasting cycle in cultured white adipocytes and white adipose tissue (WAT), respectively. Although uncoupling protein 1 (Ucp1)-dependent thermogenesis was dispensable for tumor-induced body wasting, WAT from cachectic mice and tumor-cell-supernatant-treated adipocytes were consistently characterized by the simultaneous induction of both lipolytic and lipogenic pathways. Paradoxically, this was accompanied by an inactivated AMP-activated protein kinase (Ampk), which is normally activated in peripheral tissues during states of low cellular energy. Ampk inactivation correlated with its degradation and with upregulation of the Ampk-interacting protein Cidea. Therefore, we developed an Ampk-stabilizing peptide, ACIP, which was able to ameliorate WAT wasting in vitro and in vivo by shielding the Cidea-targeted interaction surface on Ampk. Thus, our data establish the Ucp1-independent remodeling of adipocyte lipid homeostasis as a key event in tumor-induced WAT wasting, and we propose the ACIP-dependent preservation of Ampk integrity in the WAT as a concept in future therapies for cachexia.