IGFBPs and cancer.
The proposed insulin-like growth factor binding protein (IGFBP) superfamily are a group of secreted proteins that are structurally, functionally and evolutionarily related, and include six IGFBPs and over 10 IGFBP-related proteins. The IGFBPs have high affinities for insulin-like growth factors (IGFs), thereby modulating the mitogenic, anti-apoptotic and metabolic actions of IGFs. In addition, IGFBPs, particularly IGFBP-3, also have IGF-independent, anti-proliferative and pro-apoptotic functions. The IGFBPs are, in turn, modulated by proteolysis. Epidemiological data correlating serum IGF/IGFBP levels with the risk of several human cancers suggest a possible protective role for IGFBP-3. In vitro studies suggest that the potential protective effects of IGFBP-3 involve both IGF-dependent and IGF-independent mechanisms. Further studies are necessary to demonstrate whether the ability of IGFBPs to inhibit the proliferation of cancer cells under in vitro conditions has significant clinical implications.
Fang
Peng
P
Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239-3098, USA.
Hwa
Vivian
V
Rosenfeld
Ron
R
D000818:Animals; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000502:physiology*; D009369:Neoplasms / Q000378:metabolism*
D018969:Insulin-Like Growth Factor Binding Proteins