Protease-activated receptor-2 activation in gastric cancer cells promotes epidermal growth factor receptor trans-activation and proliferation.
Dysregulated epidermal growth factor receptor (EGFR) signaling is involved in gastric cancer (GC) cell growth. However, the mechanism that sustains EGFR signaling in GC remains unknown. Since protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, has been shown to trans-activate EGFR in several cell types, we examined the role of PAR-2 in GC. We show here that in vitro activation of PAR-2 enhances the growth of two GC cell lines, AGS and MKN28. In both these cell lines, PAR-2 trans-activated EGFR and inhibition of EGFR tyrosine kinase activity by AG1478 or specific EGFR siRNA completely prevented PAR-2-driven proliferation. Antibody blockade of EGF-like ligands to EGFR did not modify EGFR signaling or cell growth induced by PAR-2 activation. In contrast, PAR-2 promoted Src activation and interaction of this kinase with EGFR. In support of this, inhibition of Src kinase activity by PP1 or siRNA blocked PAR-2-induced EGFR signaling cascade and cell growth. Finally, PAR-2 was detectable in both normal and GC specimens, but its expression was more pronounced in GC than controls and correlated with activated EGFR. These data show that PAR-2 is overexpressed in GC and suggest a role of PAR-2 in EGFR trans-activation and cell growth.
Caruso
Roberta
R
Department of Internal Medicine and the Centre of Excellence for Genomic Risk Assessment in Multifactorial and Complex Diseases, University "Tor Vergata" of Rome, Rome, Italy.
Pallone
Francesco
F
Fina
Daniele
D
Gioia
Valentina
V
Peluso
Ilaria
I
Caprioli
Flavio
F
Stolfi
Carmine
C
Perfetti
Alessandra
A
Spagnoli
Luigi Giusto
LG
Palmieri
Giampiero
G
Macdonald
Thomas T
TT
Monteleone
Giovanni
G
D000230:Adenocarcinoma / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D044464:Receptor, PAR-2 / Q000187:drug effects / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology*; D019061:src-Family Kinases / Q000187:drug effects / Q000378:metabolism
D004791:Enzyme Inhibitors; D044464:Receptor, PAR-2; D066246:ErbB Receptors; D019061:src-Family Kinases