Catabolic mediators of cancer cachexiaTisdale, Michael JCurrent Opinion in Supportive and Palliative Care: December 2008 - Volume 2 - Issue 4 - p 256–261 doi: 10.1097/SPC.0b013e328319d7fa Cachexia, nutrition and hydration: Edited by Mike Tisdale and Aminah Jatoi Buy Abstract Author InformationAuthors Article MetricsMetrics Purpose of review This review compares the catabolic actions of tumour necrosis factor-α (TNF-α) and proteolysis-inducing factor (PIF) and their involvement in human cancer cachexia. Recent findings TNF-α has a direct catabolic effect on skeletal muscle and adipose tissue, whereas PIF only has an effect on skeletal muscle. Both produce muscle atrophy through a depression of protein synthesis and an increase in protein degradation through the ubiquitin-proteasome proteolytic pathway, and this involves formation of reactive oxygen species leading to upregulation of the transcription factor nuclear factor-κB (NF-κB). TNF-α depresses protein synthesis through decreased phosphorylation of eukaryotic initiation factor-4E (eIF4E) binding protein (4E-BP1) leading to increased binding of eIF4E and a reduction in the active eIF4F complex, whereas with PIF depression of protein synthesis is due to an increased phosphorylation of eIF2 on the α-subunit. In general, serum levels of TNF-α do not correlate with weight loss in cancer patients and attempts to treat cachexia by interfering with TNF-α production, or action, have not been successful. Most studies show that PIF is detectable in the urine of cachectic cancer patients and its presence is indicative of weight loss. It is best to confirm that the band on Western blotting is PIF using both antibodies to the core peptide and the oligosaccharide chains. Summary These results suggest that blocking the PIF receptor or signalling pathways in skeletal muscle might yield new types of agents for the treatment of cancer cachexia. Nutritional Biomedicine, School of Life and Health Sciences, Aston University, Birmingham, UK Correspondence to Michael J. Tisdale, Nutritional Biomedicine, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK Tel: +44 121 359 3611 ext 4193; fax: +44 121 359 0733; e-mail: M.J.Tisdale@aston.ac.uk © 2008 Lippincott Williams & Wilkins, Inc.