Aberrant expression and activation of the thrombin receptor protease-activated receptor-1 induces cell proliferation and motility in human colon cancer cells.
The traditional view on the role of serine proteases in tumor biology has changed with the recent discovery of a family of protease-activated receptors (PARs). In this study we explored the expression and functional role of the thrombin receptor PAR-1 in human colon cancer cells. Reverse transcriptase-polymerase chain reaction analysis showed that PAR-1 mRNAs are present in 11 of 14 human colon cancer cell lines tested but not in normal human colonic epithelial cells. This is in line with the immunolocalization of PAR-1 in human colon tumors and its absence in normal human colonic mucosa. The functional significance of the aberrant expression of PAR-1 in colon cancer cells was then investigated. We found that 1) a prompt increase in intracellular calcium concentration was observed on thrombin (10 nmol/L) or PAR-1 agonist AP1 (100 micro mol/L) challenge of HT29 cells; 2) HT29 quiescent cells treated with thrombin (0.01 to 20 nmol/L) or AP1 (1 to 300 micro mol/L) exhibited dramatic mitogenic responses (3.5-fold increase in cell number). Proliferative effects of thrombin or AP1 were also observed in other colon cancer cell lines expressing PAR-1. This effect was reversed by the MEK inhibitor PD98059 in consonance with the ability of thrombin or AP1 to induce phosphorylation of p42/p44 extracellular-regulated protein kinases. 3) PAR-1 activation by thrombin or AP1 led to a two-fold increase in cell motility of wounded HT29-D4. Our results demonstrate for the first time the aberrant expression of the functional thrombin receptor PAR-1 in colon cancers and its important involvement in cell proliferation and motility. Thrombin should now be considered as a growth factor for human colon cancer.
Darmoul
Dalila
D
Neuroendocrinologie et Biologie Cellulaire Digestives, INSERM U410, Institut National de la Santé et de la Recherche Médicale, Paris, France. darmoul@bichat.inserm.fr
Gratio
Valérie
V
Devaud
Hélène
H
Lehy
Thérèse
T
Laburthe
Marc
M
D002118:Calcium / Q000032:analysis; D002455:Cell Division; D002465:Cell Movement; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013917:Thrombin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D005419:Flavonoids; D006629:Hirudins; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; D013917:Thrombin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium