Modulation of adipocyte G-protein expression in cancer cachexia by a lipid-mobilizing factor (LMF)

Citation
B. Islam-ali et al., Modulation of adipocyte G-protein expression in cancer cachexia by a lipid-mobilizing factor (LMF), BR J CANC, 85(5), 2001, pp. 758-763
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oncology,"Onconogenesis & Cancer Research
Journal title
BRITISH JOURNAL OF CANCER
ISSN journal
0007-0920 → ACNP
Volume
85
Issue
5
Year of publication
2001
Pages
758 - 763
Database
ISI
SICI code
0007-0920(20010901)85:5<758:MOAGEI>2.0.ZU;2-6
Abstract
Adipocytes isolated from cachectic mice bearing the MAC 16 tumour showed ov er a 3-fold increase in lipolytic response to both low concentrations of is oprenaline and a tumour-derived lipid mobilizing factor (LMF). This was ref lected by an enhanced stimulation of adenylate cyclase in plasma membrane f ractions of adipocytes in the presence of both factors. There was no up-reg ulation of adenylate cyclase in response to forskolin, suggesting that the effect arose from a change in receptor number or G-protein expression. Immu noblotting of adipocyte membranes from mice bearing the MAC16 tumour showed an increased expression of Gas up to 10% weight loss and a reciprocal decr ease in Ga. There was also an increased expression of Gas and a decrease in Ga in adipose tissue from a patient with cancer-associated weight loss com pared with a non-cachectic cancer patient. The changes in G-protein express ion were also seen in adipose tissue of normal mice administered pure LMF a s well as in 3T3L1 adipocytes in vitro. The changes in G-protein expression induced by LMF were attenuated by the polyunsaturated fatty acid, eicosape ntaenoic acid (EPA), This suggests that this tumour-derived lipolytic facto r acts to sensitize adipose tissue to lipolytic stimuli, and that this effe ct is attenuated by EPA, which is known to preserve adipose tissue in cance r cachexia. (C) 2001 Cancer Research Campaign.