title: Modeling breast cancer-associated c-Src and EGFR overexpression in human MECs: c-Src and EGFR cooperatively promote aberrant three-dimensional acinar structure and invasive behavior.
abstract: Epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases, is overexpressed in as many as 60% cases of breast and other cancers. EGFR overexpression is a characteristic of highly aggressive molecular subtypes of breast cancer with basal-like and BRCA1 mutant phenotypes distinct from ErbB2-overexpressing breast cancers. Yet, EGFR is substantially weaker compared with ErbB2 in promoting the oncogenic transformation of nontumorigenic human mammary epithelial cells (human MEC), suggesting a role for cooperating oncogenes. Here, we have modeled the co-overexpression of EGFR and a biologically and clinically relevant potential modifier c-Src in two distinct immortal but nontumorigenic human MECs. Using a combination of morphologic analysis and confocal imaging of polarity markers in three-dimensional Matrigel culture together with functional analyses of early oncogenic traits, we show for the first time that EGFR and c-Src co-overexpression but not EGFR or c-Src overexpression alone unleashes an oncogenic signaling program that leads to hyperproliferation and loss of polarity in three-dimensional acinar cultures, marked enhancement of migratory and invasive behavior, and anchorage-independent growth. Our results establish that EGFR overexpression in an appropriate context (modeled here using c-Src overexpression) can initiate oncogenic transformation of nontumorigenic human MECs and provide a suitable in vitro model to interrogate human breast cancer-relevant oncogenic signaling pathways initiated by overexpressed EGFR and to identify modifiers of EGFR-mediated breast oncogenesis.
authors.affiliation: Division of Molecular Oncology, Evanston Northwestern Healthcare Research Institute, Evanston, IL 60201, USA.
authors.forename: Manjari
authors.initials: M
authors.lastname: Dimri
authors.forename: Mayumi
authors.initials: M
authors.lastname: Naramura
authors.forename: Lei
authors.initials: L
authors.lastname: Duan
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Cesar
authors.initials: C
authors.lastname: Ortega-Cava
authors.forename: Gengsheng
authors.initials: G
authors.lastname: Chen
authors.forename: Rasna
authors.initials: R
authors.lastname: Goswami
authors.forename: Norvin
authors.initials: N
authors.lastname: Fernandes
authors.forename: Qingshen
authors.initials: Q
authors.lastname: Gao
authors.forename: Goberdhan P
authors.initials: GP
authors.lastname: Dimri
authors.forename: Vimla
authors.initials: V
authors.lastname: Band
authors.forename: Hamid
authors.initials: H
authors.lastname: Band
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D000081247:CSK Tyrosine-Protein Kinase; D002448:Cell Adhesion / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D002471:Cell Transformation, Neoplastic / Q000378:metabolism* / Q000473:pathology; D003094:Collagen; D004338:Drug Combinations; D004847:Epithelial Cells / Q000201:enzymology / Q000473:pathology; D066246:ErbB Receptors / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007797:Laminin; D051379:Mice; D008819:Mice, Nude; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis*; D011509:Proteoglycans; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
chemical_list: D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human