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Transactivation of epidermal growth factor receptor after heparin‐binding epidermal growth factor‐like growth factor shedding in the migration of prostate cancer cells promoted by bombesin
Author(s) -
Madarame Jun,
Higashiyama Shigeki,
Kiyota Hiroshi,
Madachi Ayako,
Toki Fujio,
Shimomura Tatsuya,
Tani Naoyuki,
Oishi Yukihiko,
Matsuura Nariaki
Publication year - 2003
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.10295
Subject(s) - bombesin , epidermal growth factor , epidermal growth factor receptor , heparin binding egf like growth factor , growth factor , biology , receptor , cancer research , microbiology and biotechnology , chemistry , medicine , endocrinology , biochemistry , neuropeptide
Abstract BACKGROUND A pathway consisting of bombesin, G‐protein coupling receptors (GPCRs), metalloproteases, pro‐heparin‐binding epidermal growth factor (proHB‐EGF), and epidermal growth factor receptor (EGFR) has been reported in prostate cancer cells. The occurrence of HB‐EGF shedding from proHB‐EGF in this pathway, however, has not been proven directly. In addition, it is still unclear how much this pathway contributes to the migration of prostate cancer cells. In this study, we tried to directly elucidate HB‐EGF shedding in this pathway and to determine its contribution to the migration of prostate cancer cells. METHODS RT‐PCR and indirect immunofluorescence staining for HB‐EGF and its receptors, such as EGFR and HER4/erbB4, were performed on PC‐3 cells. The influences of bombesin, anti‐EGFR neutralizing monoclonal antibody, HB‐EGF, and HB‐EGF shedding inhibitor on the migration of PC‐3 cells were studied by means of in vitro wound assays. The amount of HB‐EGF shed from PC‐3 cells with alkaline phosphatase‐tagged HB‐EGF in the presence of bombesin was determined by measuring AP activity. Immunoprecipitations and phosphotyrosine Western blotting were performed to detect EGFR transactivated by bombesin. RESULTS PC‐3 expressed HB‐EGF and EGFR, but not HER4/erbB4. PC‐3 migrated in the presence of bombesin, but its migration was partly inhibited by the neutralizing antibody against EGFR. PC‐3 also migrated in the presence of HB‐EGF, but HB‐EGF shedding inhibitor partly inhibited this phenomenon. HB‐EGF was shed from PC‐3 cells in the presence of bombesin, and this shedding was inhibited by HB‐EGF shedding inhibitor. In addition, the EGFR on PC‐3 was activated in the presence of bombesin and inactivated in the presence of HB‐EGF shedding inhibitor. CONCLUSIONS These results indicated that HB‐EGF shedding and the following transactivation of EGFR occurs in this pathway and that this pathway partly contributes to the migration of prostate cancer cells. Prostate 57: 187–195, 2003. © 2003 Wiley‐Liss, Inc.