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This Article Full Text Full Text (PDF) All Versions of this Article: JME-09-0035v1 44/2/115    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Accornero, P. Articles by Baratta, M. PubMed PubMed Citation Articles by Accornero, P. Articles by Baratta, M.

Department of Veterinary Morphophysiology, University of Torino, Via Leonardo da Vinci 44, 10095 Grugliasco, (TO), Italy

(Correspondence should be addressed to P Accornero; Email: paolo.accornero{at}unito.it)

*(P Accornero and S Miretti contributed equally to this work)

The development of the mammary gland requires an integrated response to specific growth factors and steroid hormones. Hepatocyte growth factor (HGF) and its tyrosine kinase receptor, MET, are expressed and temporally regulated during mammary development and differentiation. Epidermal growth factor receptor (EGFR) and its ligands have also been implicated in mammary gland growth and morphogenesis. Since both cytokines seem to exert a morphogenic program in this tissue, we have investigated the possible concerted action of EGF and HGF on the HC11 cell line, a widely used model of nontumorigenic mammary cells. Western blot analysis indicated that HC11 expressed MET and EGFR, and showed ERK1/2 and AKT activation following HGF or EGF treatment. Analysis by real-time PCR and western blot showed that after an EGF but not HGF or insulin-like growth factor-I treatment, HC11 mammary cells exhibited an increase in MET expression at both the mRNA and protein levels, which was dependent on the AKT pathway. Simultaneous treatment with HGF and EGF increased proliferation, scatter, and invasion as assessed by cell count, cell cycle, scatter, and transwell assays. AKT inhibition did not influence the cooperation on proliferation or invasion after HGF+EGF treatment, while ERK1/2 inhibition abolished MET/EGFR cooperation on proliferation. HGF+EGF treatment increased the duration of ERK1/2 and AKT activation compared to HGF or EGF alone. All these data indicate that a crosstalk between the EGF and HGF pathways in mammary epithelial cells may modulate the development of the mammary gland.