Anti-IGFBP5 Antibody Picoband® Fluoro550 Conjugated

Insulin-like growth factor-binding protein 5 is a protein that in humans is encoded by the IGFBP5 gene. The expression of IGFBP5 by stable transfection and adenovirus-mediated infection is inhibitory to growth in 2 human breast cancer cell lines. IGFBP5 expression leads to G2/M cell cycle arrest and apoptosis. Stable expression of IGFBP5 in the breast cancer cell lines also inhibits the formation and growth of tumors following injection in athymic mice. It is concluded that IGFBP5 is a growth inhibitor and proapoptotic agent in breast cancer cells. Additionally, IGFBP-5 is expressed by fibroblasts, myoblasts and osteoblasts, making it the predominant IGFBP found in bone extracts. It has a strong affinity for hydroxyapatite, allowing it to bind to bone cells. When bound to extracellular matrix, IGFBP-5 is protected from proteolysis and potentiates IGF activity, but when it is soluble, IGFBP-5 is cleaved to a biologically inactive 21 kDa fragment (1, 2) .

E. coli-derived human IGFBP5 recombinant protein (Position: A60-E272) . Human IGFBP5 shares 96.7% and 96.2% amino acid (aa) sequence identity with mouse and rat IGFBP5, respectively.

IGF-binding proteins prolong the half-life of the IGFs and have been shown to either inhibit or stimulate the growth promoting effects of the IGFs on cell culture. They alter the interaction of IGFs with their cell surface receptors.

1. Allander SV, Larsson C, Ehrenborg E, Suwanichkul A, Weber G, Morris SL, Bajalica S, Kiefer MC, Luthman H, Powell DR (May 1994) . Characterization of the chromosomal gene and promoter for human insulin-like growth factor binding protein-5. J Biol Chem 269 (14) : 10891–8. 2. Butt, A. J., Dickson, K. A., McDougall, F., Baxter, R. C. Insulin-like growth factor-binding protein-5 inhibits the growth of human breast cancer cells in vitro and in vivo. J. Biol. Chem. 278: 29676-29685, 2003.