Hyperlipemia: a role in regulating UCP3 gene expression in skeletal muscleduring cancer cachexia?

Rats bearing the Yoshida AH-130 ascites hepatoma showed an increased expres sion of both uncoupling protein-2 (UCP2) (two-fold) and UCP3 (three- to fou r-fold) in skeletal muscle (both soleus and gastrocnemius). The increase in mRNA content was associated with increased circulating concentrations of f atty acids (two-fold), triglyceride (two-fold) and cholesterol (1.9-fold). Administration of nicotinic acid to tumor-bearing rats abolishes the hyperl ipidemic increase associated with tumor burden. The vitamin treatment also resulted in a decreased UCP3 gene expression in soleus muscle but not in ga strocnemius. It is concluded that circulating fatty acids may be involved i n the regulation of UCP3 gene expression in aerobic muscles during experime ntal cancer cachexia. Since the UCP3 protein could have a role in energy ex penditure, it may be suggested that hypolipidemic agents may have a benefic ial role in the treatment of the cachectic syndrome. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical S ocieties.