title: Hyaluronan constitutively regulates activation of COX-2-mediated cell survival activity in intestinal epithelial and colon carcinoma cells.
abstract: Hyaluronan is a major component of the pericellular matrix surrounding tumor cells, including colon carcinomas. Elevated cycooxygenase-2 levels have been implicated in several malignant properties of colon cancer. We now show for the first time a strong link between hyaluronan-CD44 interaction and cyclooxygenase-2 in colon cancer cells. First, we have shown that increased expression of hyaluronan synthase-2 induces malignant cell properties, including increased proliferation, anchorage-independent growth, and epithelial-mesenchymal transition in HIEC6 cells. Second, constitutive hyaluronan-CD44 interaction stimulates a signaling pathway involving ErbB2, phosphoinositide 3-kinase/AKT, beta-catenin, and cyclooxygenase-2/prostaglandin E(2) in HCA7 colon carcinoma cells. Third, the HA/CD44-activated ErbB2 --> phosphoinositide 3-kinase/AKT --> beta-catenin pathway stimulates cell survival/cell proliferation through COX-2 induction in hyaluronan-overexpressing HIEC6 cells and in HCA7 cells. Fourth, perturbation of hyaluronan-CD44 interaction by hyaluronan oligomers or CD44-silencing RNA decreases cyclooxygenase-2 expression and enzyme activity, and inhibition of cyclooxygenase-2 decreases hyaluronan production suggesting the possibility of an amplifying positive feedback loop between hyaluronan and cyclooxygenase-2. We conclude that hyaluronan is an important endogenous regulator of colon cancer cell survival properties and that cyclooxygenase-2 is a major mediator of these hyaluronan-induced effects. Defining hyaluronan-dependent cyclooxygenase-2/prostaglandin E(2)-associated signaling pathways will provide a platform for developing novel therapeutic approaches for colon cancer.
authors.affiliation: Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, SC 29425, USA. misra@musc.edu
authors.forename: Suniti
authors.initials: S
authors.lastname: Misra
authors.forename: Lina M
authors.initials: LM
authors.lastname: Obeid
authors.forename: Yusuf A
authors.initials: YA
authors.lastname: Hannun
authors.forename: Susumu
authors.initials: S
authors.lastname: Minamisawa
authors.forename: Franklin G
authors.initials: FG
authors.lastname: Berger
authors.forename: Roger R
authors.initials: RR
authors.lastname: Markwald
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Toole
authors.forename: Shibnath
authors.initials: S
authors.lastname: Ghatak
mesh_terms: D002470:Cell Survival; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D051176:beta Catenin / Q000378:metabolism
chemical_list: D051546:Cyclooxygenase 2; D006820:Hyaluronic Acid; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D018719:Erb-b2 Receptor Tyrosine Kinases; D051176:beta Catenin