title: The hyaluronan receptors CD44 and Rhamm (CD168) form complexes with ERK1,2 that sustain high basal motility in breast cancer cells.
abstract: CD44 is an integral hyaluronan receptor that can promote or inhibit motogenic signaling in tumor cells. Rhamm is a nonintegral cell surface hyaluronan receptor (CD168) and intracellular protein that promotes cell motility in culture. Here we describe an autocrine mechanism utilizing cell surface Rhamm-CD44 interactions to sustain rapid basal motility in invasive breast cancer cell lines that requires endogenous hyaluronan synthesis and the formation of Rhamm-CD44-ERK1,2 complexes. Motile/invasive MDA-MB-231 and Ras-MCF10A cells produce more endogenous hyaluronan, cell surface CD44 and Rhamm, an oncogenic Rhamm isoform, and exhibit more elevated basal activation of ERK1,2 than less invasive MCF7 and MCF10A breast cancer cells. Furthermore, CD44, Rhamm, and ERK1,2 uniquely co-immunoprecipitate and co-localize in MDA-MB-231 and Ras-MCF10A cells. Combinations of anti-CD44, anti-Rhamm antibodies, and a MEK1 inhibitor (PD098059) had less-than-additive blocking effects, suggesting the action of all three proteins on a common motogenic signaling pathway. Collectively, these results show that cell surface Rhamm and CD44 act together in a hyaluronan-dependent autocrine mechanism to coordinate sustained signaling through ERK1,2, leading to high basal motility of invasive breast cancer cells. Therefore, an effect of CD44 on tumor cell motility may depend in part on its ability to partner with additional proteins, such as cell surface Rhamm.
authors: London Regional Cancer Program, London Health Sciences Centre, and The University of Western Ontario, London, and Department of Cardiovascular Research, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
authors: Sara R
authors: SR
authors: Hamilton
authors: Shireen F
authors: SF
authors: Fard
authors: Frouz F
authors: FF
authors: Paiwand
authors: Cornelia
authors: C
authors: Tolg
authors: Mandana
authors: M
authors: Veiseh
authors: Chao
authors: C
authors: Wang
authors: James B
authors: JB
authors: McCarthy
authors: Mina J
authors: MJ
authors: Bissell
authors: James
authors: J
authors: Koropatnick
authors: Eva A
authors: EA
authors: Turley
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D019898:Autocrine Communication / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects; D046912:Multiprotein Complexes / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; C497483:CD44 protein, human; D016326:Extracellular Matrix Proteins; D005419:Flavonoids; D018960:Hyaluronan Receptors; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D020033:Protein Isoforms; C098946:hyaluronan-mediated motility receptor; D006820:Hyaluronic Acid; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one