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.
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.
Dimri
Manjari
M
Division of Molecular Oncology, Evanston Northwestern Healthcare Research Institute, Evanston, IL 60201, USA.
Naramura
Mayumi
M
Duan
Lei
L
Chen
Jing
J
Ortega-Cava
Cesar
C
Chen
Gengsheng
G
Goswami
Rasna
R
Fernandes
Norvin
N
Gao
Qingshen
Q
Dimri
Goberdhan P
GP
Band
Vimla
V
Band
Hamid
H
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
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