title: Trypsin is produced by and activates protease-activated receptor-2 in human cancer colon cells: evidence for new autocrine loop.
abstract: In this work, we showed that human colon cancer cell lines produce trypsin which can activate a receptor for trypsin, the protease-activated receptor-2 (PAR-2), in these cells. RT-PCR experiments showed that trypsinogen transcripts were present in four colon cancer cell lines: T84, Caco-2, HT-29 and C1.19A. By Western blot analysis we found a 25 kDa immunoreactive band identified as trypsinogen I in cell lysates and in the corresponding culture media. Concentrations of trypsin in cell media were found in nanomolar range, thus compatible with activation of protease-activated receptor 2 (PAR-2). This was further demonstrated in a colon cancer cell line (H-29) Ca2+i assay since increases in Ca2+i were observed in response to media from T84, Caco-2 or C1.19A cells that were similar to that observed with 2-5 nM trypsin and were abolished by trypsin inhibitor. Altogether, these data show that colon cancer cell lines produce and secrete trypsin at concentrations compatible with activation of PAR-2. They support possible autocrine/paracrine regulation of PAR-2 activity by trypsin in colon cancer cells.
authors.affiliation: Neuroendocrinologie et Biologie Cellulaire Digestives, INSERM U410, Faculté de Médecine X. Bichat, Paris, France. ducroc@bichat.inserm.fr
authors.forename: Robert
authors.initials: R
authors.lastname: Ducroc
authors.forename: Claire
authors.initials: C
authors.lastname: Bontemps
authors.forename: Katia
authors.initials: K
authors.lastname: Marazova
authors.forename: Hélène
authors.initials: H
authors.lastname: Devaud
authors.forename: Dalila
authors.initials: D
authors.lastname: Darmoul
authors.forename: Marc
authors.initials: M
authors.lastname: Laburthe
mesh_terms: D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000494:pharmacology; D017931:DNA Primers / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006801:Humans; D036103:Nanotechnology; D010940:Plant Proteins / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014357:Trypsin / Q000096:biosynthesis* / Q000494:pharmacology; D014361:Trypsin Inhibitors; D014362:Trypsinogen / Q000096:biosynthesis / Q000235:genetics; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D000516:alpha-Amylases / Q000037:antagonists & inhibitors
chemical_list: D017077:Culture Media, Conditioned; D017931:DNA Primers; D010940:Plant Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin; D014361:Trypsin Inhibitors; D014362:Trypsinogen; D000516:alpha-Amylases; D014357:Trypsin; D002118:Calcium