Protease-activated receptor-2 is essential for factor VIIa and Xa-induced signaling, migration, and invasion of breast cancer cells.
Protease-activated receptors (PAR) are G protein-coupled receptors that function as cell-surface sensors for coagulant proteases, as well as other proteases associated with the tumor microenvironment. PAR1 is activated by thrombin whereas the upstream coagulant protease VIIa bound to tissue factor and Xa can activate both PAR1 and PAR2. PAR1 has been implicated in tumor cell growth, migration, and invasion whereas the function of PAR2 in these processes is largely unknown. Towards defining the functional importance of PAR2 in cancer cells, we used small interfering RNAs to deplete highly invasive breast cancer cells of endogenous PAR proteins. Our findings strongly suggest that PAR2 is critical for MDA-MB-231 and BT549 breast cancer cell migration and invasion towards NIH 3T3 fibroblast conditioned medium. To define the relative importance of PAR1 versus PAR2 in mediating factor VIIa and Xa responses, we assessed signaling in cancer cells lacking either endogenous PAR1 or PAR2 proteins. Strikingly, in MDA-MB-231 cells depleted of PAR2, we observed a marked inhibition of VIIa and Xa signaling to phosphoinositide hydrolysis and extracellular signal-regulated kinase 1/2 activation whereas signaling by VIIa and Xa remained intact in PAR1-deficient cells. Factor VIIa and Xa-induced cellular migration was also impaired in MDA-MB-231 cells deficient in PAR2 but not in cells lacking PAR1. Together, these studies reveal the novel findings that PAR2, a second protease-activated G protein-coupled receptor, has a critical role in breast cancer cell migration and invasion and functions as the endogenous receptor for coagulant proteases VIIa and Xa in these cells.
Morris
Dionne R
DR
Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365, USA.
Ding
Yu
Y
Ricks
Tiffany K
TK
Gullapalli
Anuradha
A
Wolfe
Breann L
BL
Trejo
JoAnn
J
D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology*; D015942:Factor VIIa / Q000378:metabolism*; D015951:Factor Xa / Q000378:metabolism*; D006801:Humans; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D009361:Neoplasm Invasiveness; D034741:RNA, Small Interfering / Q000235:genetics; D044463:Receptor, PAR-1 / Q000235:genetics / Q000502:physiology; D044464:Receptor, PAR-2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
D034741:RNA, Small Interfering; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D048052:Mitogen-Activated Protein Kinase 3; D015942:Factor VIIa; D015951:Factor Xa