title: Molecular forms of the insulin-like growth factor-binding protein-2 in patients with colorectal cancer.
abstract: The components of the insulin-like growth factor (IGF) system and molecules with which they interact are associated with the neoplastic transformation of cells in colorectal cancer. The IGF-binding protein-2 (IGFBP-2) plays a significant role in mitotic stimulation of the cancer cells and its concentration is significantly elevated in tumor states. Little is known about IGFBP-2 at the molecular level and the purpose of this study was to examine the interactions between IGFBP-2 and some other proteins, the fragmentation pattern and posttranslational modifications that might have occurred due to a disease. Results have shown that the amount of monomer IGFBP-2 was 20-30% greater in patients with cancer and the amount of fragmented IGFBP-2 was doubled compared to healthy people, whereas the portion of IGFBP-2 in complex with α2 macroglobulin (α2M) was 2.5 times lower in cancer patients. According to this distribution, IGFBP-2 was not only increasingly synthetized in patients with cancer, but also the amount involved in complexes with α2M was reduced favoring the existence of binary IGFBP-2/IGF complexes, free to leave the circulation. Both IGFBP-2 and α2M were significantly more oxidized in patients with colon cancer than in healthy individuals and α2M was additionally sialylated. It can be speculated that the formation of IGFBP-2/α2M complexes is part of the control mechanism involved in the regulation of IGFBP-2 and, consequently, IGF availability. It also seems that posttranslational modifications are more important factors in determining the amount of IGFBP-2/α2M complexes than the actual quantity of these two proteins.
authors.affiliation: Institute for the Application of Nuclear Energy (INEP), University of Belgrade, Serbia. Electronic address: milos@inep.co.rs.
authors.forename: Miloš
authors.initials: M
authors.lastname: Šunderić
authors.affiliation: Clinical-Medical Centre "Bežanijska Kosa", Belgrade, Serbia.
authors.forename: Blagoje
authors.initials: B
authors.lastname: Đukanović
authors.affiliation: Clinical-Medical Centre "Bežanijska Kosa", Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Malenković
authors.affiliation: Institute for the Application of Nuclear Energy (INEP), University of Belgrade, Serbia.
authors.forename: Olgica
authors.initials: O
authors.lastname: Nedić
mesh_terms: D000368:Aged; D015153:Blotting, Western; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: C577903:IGFBP2 protein, human; D018971:Insulin-Like Growth Factor Binding Protein 2; D000511:alpha-Macroglobulins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II
keywords: Colorectal cancer; IGFBP-2; Oxidation; Protein complexes; Sialylation; α2 macroglobulin