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

Rats bearing the Yoshida AH-130 ascites hepatoma showed an increased expression of both uncoupling protein-2 (UCP2) (two-fold) and UCP3 (three- to four-fold) in skeletal muscle (both soleus and gastrocnemius). The increase in mRNA content was associated with increased circulating concentrations of fatty acids (two-fold), triglyceride (two-fold) and cholesterol (1.9-fold). Administration of nicotinic acid to tumor-bearing rats abolishes the hyperlipidemic increase associated with tumor burden. The vitamin treatment also resulted in a decreased UCP3 gene expression in soleus muscle but not in gastrocnemius. It is concluded that circulating fatty acids may be involved in the regulation of UCP3 gene expression in aerobic muscles during experimental cancer cachexia. Since the UCP3 protein could have a role in energy expenditure, it may be suggested that hypolipidemic agents may have a beneficial role in the treatment of the cachectic syndrome.