title: Celecoxib increases EGF signaling in colon tumor associated fibroblasts, modulating EGFR expression and degradation.
abstract: We previously demonstrated that non-toxic doses of Celecoxib induced the immediate phosphorylation of Erk1-2 in colon tumor associated fibroblasts (TAFs), increasing their responsiveness to epidermal growth factor (EGF). We have now identified two concomitant mechanisms explaining the EGF-Celecoxib cooperation. We found that a 24-48h Celecoxib priming increased EGF receptor (EGFR) mRNA and protein levels in colon TAFs, promoting EGF binding and internalization. Celecoxib-primed TAFs showed a reduced EGFR degradation after EGF challenge. This delay corresponded to a deferred dissociation of EEA1 from EGFR positive endosomes and the accumulation of Rab7, pro Cathepsin-D and SQSTM1/p62, suggesting a shared bottleneck in the pathways of late-endosomes/autophagosomes maturation. Celecoxib modulated the levels of target proteins similarly to the inhibitors of endosome/lysosome acidification Bafilomycin-A1 and NH(4)Cl. Cytoplasmic vesicles fractionation showed a reduced maturation of Cathepsin-D in late endosomes and an increased content of EGFR and Rab7 in lysosomes of Celecoxib-treated TAFs.Our data indicate a double mechanism mediating the increased response to EGF of colon TAFs treated with Celecoxib. While EGFR overexpression could be targeted using anti EGFR drugs, the effects on endosome trafficking and protein turnover represents a more elusive target and should be taken into account for any long-term therapy with Celecoxib.
authors.affiliation: Immunology Lab, IRCCS AOU San Martino - IST, Genoa, Italy.|Molecular Oncology and Angiogenesis Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Venè
authors.affiliation: Molecular Oncology and Angiogenesis Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Tosetti
authors.affiliation: Immunology Lab, IRCCS AOU San Martino - IST, Genoa, Italy.|Molecular Oncology and Angiogenesis Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Minghelli
authors.affiliation: Molecular Oncology and Angiogenesis Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Poggi
authors.affiliation: Molecular Oncology and Angiogenesis Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Ferrari
authors.affiliation: Immunology Lab, IRCCS AOU San Martino - IST, Genoa, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Benelli
mesh_terms: D015153:Blotting, Western; D000068579:Celecoxib / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000187:drug effects / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D021381:Protein Transport / Q000187:drug effects; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D004815:Epidermal Growth Factor; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068579:Celecoxib
keywords: EGFR; celecoxib; colon; fibroblast