title: The expression of integrins is decreased in colon cancer cells treated with polysaccharide K.
abstract: Polysaccharide K (PSK), a protein-bound polysaccharide used as a non-specific immunotherapeutic agent, is said to improve the prognosis of malignant tumors such as colon cancer, but there have been few in‑depth investigations of its mechanism of action. In the present study, we investigated which genes in colon cancer cells themselves are regulated by PSK and what sort of action it exerts. Colon cancer cells were exposed to PSK in vitro and changes to their morphology and adhesive capacity were investigated, as were the changes in integrin expression that occurred. Exposure to PSK caused colon cancer cells to become spherical in morphology and investigation of their adhesion rate showed that it reduced adhesion to laminin, fibrinogen, collagen IV, collagen I and fibronectin. In terms of changes to molecules on the surface of cancer cells, there was reduced expression of integrin mRNA α and β, which are ligands for the proteins of basement membrane. An investigation of the adhesiveness of PSK-stimulated colon cancer cells to vascular endothelial cells also showed that the adhesion rate decreased significantly compared with cells not exposed to PSK. Suppression of integrin expression on the cell surface and reduced adhesion to vascular endothelial cells were observed as a novel mechanism of action of PSK on colon cancer cells.
authors: First Department of Surgery, University of Fukui, Yoshida-gun, Fukui, Japan.
authors: Keiko
authors: K
authors: Aso
authors: Takanori
authors: T
authors: Goi
authors: Toshiyuki
authors: T
authors: Nakazawa
authors: Youhei
authors: Y
authors: Kimura
authors: Yasuo
authors: Y
authors: Hirono
authors: Kanji
authors: K
authors: Katayama
authors: Akio
authors: A
authors: Yamaguchi
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D003110:Colonic Neoplasms; D015870:Gene Expression / Q000187:drug effects; D045325:HCT116 Cells; D019073:HT29 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000502:physiology; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism*; D011509:Proteoglycans / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D015815:Cell Adhesion Molecules; D016023:Integrins; D011509:Proteoglycans; C010770:polysaccharide-K