PTPase inhibition restores ERK1/2 phosphorylation and protects mammary epithelial cells from apoptosis.
Specific survival signals derived from extracellular matrix (ECM) and growth factors are required for mammary epithelial cell survival. We have previously demonstrated that inhibition of ECM-induced ERK1/2 MAPK pathway with PD98059 leads to apoptosis in primary mouse mammary epithelial cells. In this study, we have further investigated MAPK signal transduction in cell survival of these cells cultured on a laminin rich reconstituted basement membrane. ERK1/2 phosphorylation is activated in the absence of insulin by cell-cell substratum interactions that cause ligand-independent EGFR transactivation. Intact EGFR signal transduction is required for ECM determined cell survival as the EGFR pathway inhibitor, AG1478, induces apoptosis of these cultures. Rescue of AG1478 or PD98059 treated cultures by PTPase inhibition with vanadate restores cellular phospho-ERK1/2 levels and prevents apoptosis. These results emphasize that ERK1/2 phosphorylation and inhibition of PTPase activity are necessary for PMMEC cell survival.
Furlong
Fiona
F
UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Ireland. fiona.furlong@ucd.ie
Finlay
Darren
D
Martin
Finian
F
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002448:Cell Adhesion; D002470:Cell Survival; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology*; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D007328:Insulin / Q000502:physiology; D007797:Laminin / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011799:Quinazolines; D020032:Tyrphostins / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
D005419:Flavonoids; D007328:Insulin; D007797:Laminin; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D020032:Tyrphostins; C101044:RTKI cpd; D014638:Vanadates; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D017027:Protein Tyrosine Phosphatases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one