title: Overexpression of HER2 (erbB2) in human breast epithelial cells unmasks transforming growth factor beta-induced cell motility.
abstract: We have examined overexpression of the human epidermal growth factor receptor 2 (HER2) to determine if it modifies the anti-proliferative effect of transforming growth factor (TGF)-beta against MCF-10A human mammary epithelial cells. Exogenous TGF-beta inhibited cell proliferation and induced Smad-dependent transcriptional reporter activity in both MCF-10A/HER2 and MCF-10A/vector control cells. Ligand-induced reporter activity was 7-fold higher in HER2-overexpressing cells. In wound closure and transwell assays, TGF-beta induced motility of HER2-transduced, but not control cells. The HER2-blocking antibody trastuzumab (Herceptin) prevented TGF-beta-induced cell motility. Expression of a constitutively active TGF-beta type I receptor (ALK5(T204D)) induced motility of MCF-10A/HER2 but not MCF-10A/vector cells. TGF-beta-induced motility was blocked by coincubation with either the phosphatidylinositol 3-kinase inhibitor LY294002, the mitogen-activated protein kinase (MAPK) inhibitor U0126, the p38 MAPK inhibitor SB202190, and an integrin beta(1) blocking antibody. Rac1 activity was higher in HER2-overexpressing cells, where both Rac1 and Pak1 proteins were constitutively associated with HER2. Both exogenous TGF-beta and transduction with constitutively active ALK5 enhanced this association. TGF-beta induced actin stress fibers as well as lamellipodia within the leading edge of wounds. Herceptin blocked basal and TGF-beta-stimulated Rac1 activity but did not repress TGF-beta-stimulated transcriptional reporter activity. These data suggest that 1) overexpression of HER2 in nontumorigenic mammary epithelial is permissive for the ability of TGF-beta to induce cell motility and Rac1 activity, and 2) HER2 and TGF-beta signaling cooperate in the induction of cellular events associated with tumor progression.
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt-Ingram Comprehensive Cancer Center, Nashville, Tennessee 37232, USA.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ueda
authors.forename: Shizhen
authors.initials: S
authors.lastname: Wang
authors.forename: Nancy
authors.initials: N
authors.lastname: Dumont
authors.forename: Jae Youn
authors.initials: JY
authors.lastname: Yi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koh
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Arteaga
mesh_terms: D000199:Actins / Q000378:metabolism; D030201:Activin Receptors, Type I / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000378:metabolism*; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002070:Butadienes / Q000494:pharmacology; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement; D002867:Chromones / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D018450:Disease Progression; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D019012:Integrin beta1 / Q000276:immunology; D008024:Ligands; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases; D011554:Pseudopodia / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D015398:Signal Transduction; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D000068878:Trastuzumab; D014945:Wound Healing; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000199:Actins; D030201:Activin Receptors, Type I; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D001973:Bromodeoxyuridine; D002070:Butadienes; D002867:Chromones; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D049452:Green Fluorescent Proteins; D007093:Imidazoles; D019012:Integrin beta1; D008024:Ligands; D008164:Luminescent Proteins; D009025:Morpholines; D009570:Nitriles; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines; D018719:Erb-b2 Receptor Tyrosine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D000068878:Trastuzumab; D020830:rac1 GTP-Binding Protein; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C000625841:TGFBR1 protein, human; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole