title: Role of Runx2 in crosstalk between Mek/Erk and PI3K/Akt signaling in MCF-10A cells.
abstract: Crosstalk among mitogen-activated protein kinase (MAPK) and phosphatidyl inositol 3' kinase (PI3K) signaling pathways integrates extracellular cues to regulate mammary epithelial cell growth, proliferation, differentiation, and survival. The runt-related transcription factor, Runx2, is expressed in normal mammary epithelium and promotes differentiation, however, its function in regulation of the MAPK and PI3K signaling crosstalk is not known. We determined the function of Runx2 expression in growth factor-mediated phosphorylation of Erk1/2 and Akt, key downstream kinases in MAPK and PI3K pathway crosstalk in MCF-10A mammary epithelial cells. The Runx2-mediated alterations in cell signaling and associated changes in phenotype were determined by real-time quantitative PCR, Western blotting, immunofluorescence, and flow cytometry approaches. The results revealed that ectopic Runx2 expression differentially downregulates the growth factor (EGF vs. IGF or insulin)-induced pErk1/2 and pAkt levels. Additionally, the ectopic Runx2 expression increases FOXO1 levels, cell cycle G1 stage and promotes survival of MCF-10A cells. Furthermore, we demonstrate that Runx2 expression increases EGF-induced phosphorylation of epidermal growth factor receptor (pEGFR) and relieves Mek/Erk-mediated negative regulation of pEGFR and pAkt levels. Altogether, our results identify functions of Runx2 in MAPK and PI3K signaling crosstalk in MCF-10A cells that could be critical in understanding the mammary epithelial cell growth and survival.
authors.affiliation: Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Manish
authors.initials: M
authors.lastname: Tandon
authors.forename: Zujian
authors.initials: Z
authors.lastname: Chen
authors.forename: Jitesh
authors.initials: J
authors.lastname: Pratap
mesh_terms: D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000502:physiology*; D004815:Epidermal Growth Factor / Q000502:physiology; D004847:Epithelial Cells / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D059585:G1 Phase Cell Cycle Checkpoints; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D042361:Mammary Glands, Human / Q000166:cytology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D020239:Receptor Cross-Talk
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C493709:RUNX2 protein, human; D004815:Epidermal Growth Factor; D019869:Phosphatidylinositol 3-Kinases; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases
keywords: AKT; EGFR; ERK; MAPK; PI3K; RUNX2; SIGNALING CROSSTALK