title: Heparin-derived disaccharides modulate proliferation and Erb-B2-mediated signal transduction in colon cancer cell lines.
abstract: Organ-specific extracellular matrix (ECM) determines metastasis formation by regulating tumor cell proliferation. Hepatocyte-derived ECM enhances proliferation of colon cancer cell lines by increasing expression of tyrosine kinase receptors of the erb-B family. The active components in the ECM are the heparan sulfates, which are highly heterogeneous in their chemistry and size. We determined the effect of heparan sulfate disaccharides, of defined chemistry and present in high amounts in the liver heparan sulfate chains, on the proliferation of colon cancer cell lines and investigated the mechanism involved. The low-metastatic cell line KM12 was stimulated to proliferate by a highly sulfated disaccharide, found in the highest amounts in hepatocyte-derived heparan sulfate. Growth of the highly metastatic cell line KM12SM was inhibited by the second most common disaccharide in hepatocyte-derived heparan sulfate. The effect of both disaccharides was not accompanied by changes in the expression of erb-B1, erb-B2, erb-B3 or heregulin-alpha. We determined whether the disaccharides modified the signal-transduction pathways mediated by the erb-B receptors. The erb-B2-specific tyrosine kinase inhibitor AG825 abolished the enhancement of KM12 cell proliferation by the stimulatory disaccharide. This disaccharide increased tyrosine phosphorylation of erb-B1 and erb-B2 receptors, effects that were abolished by AG825. Moreover, the disaccharide caused increased expression of cyclin D1 and of activated MAP kinase, again reduced in the presence of the inhibitor AG825. The growth-inhibitory disaccharide reduced phosphorylation of erb-B1, but not of erb-B2, receptors in KM12SM cells. In conclusion, not only hepatocyte-derived heparan sulfate but also disaccharide molecules derived from heparan sulfate can affect colon cancer cell proliferation. Their effect is mediated by modulation of the erb-B signal transduction.
authors.affiliation: Liver Metastasis Research Group, Gastroenterology Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Sigal
authors.initials: S
authors.lastname: Fishman
authors.forename: Shlomo
authors.initials: S
authors.lastname: Brill
authors.forename: Moshe
authors.initials: M
authors.lastname: Papa
authors.forename: Zamir
authors.initials: Z
authors.lastname: Halpern
authors.forename: Isabel
authors.initials: I
authors.lastname: Zvibel
mesh_terms: D002455:Cell Division / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D004187:Disaccharides / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006493:Heparin / Q000737:chemistry*; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured
chemical_list: D004187:Disaccharides; D004791:Enzyme Inhibitors; D004815:Epidermal Growth Factor; D006493:Heparin; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases