Epidermal growth factor receptor and mutant p53 expand an esophageal cellular subpopulation capable of epithelial-to-mesenchymal transition through ZEB transcription factors.
Transforming growth factor-beta (TGF-beta) is a potent inducer of epithelial to mesenchymal transition (EMT). However, it remains elusive about which molecular mechanisms determine the cellular capacity to undergo EMT in response to TGF-beta. We have found that both epidermal growth factor receptor (EGFR) overexpression and mutant p53 tumor suppressor genes contribute to the enrichment of an EMT-competent cellular subpopulation among telomerase-immortalized human esophageal epithelial cells during malignant transformation. EGFR overexpression triggers oncogene-induced senescence, accompanied by the induction of cyclin-dependent kinase inhibitors p15(INK4B), p16(INK4A), and p21. Interestingly, a subpopulation of cells emerges by negating senescence without loss of EGFR overexpression. Such cell populations express increased levels of zinc finger E-box binding (ZEB) transcription factors ZEB1 and ZEB2, and undergo EMT on TGF-beta stimulation. Enrichment of EMT-competent cells was more evident in the presence of p53 mutation, which diminished EGFR-induced senescence. RNA interference directed against ZEB resulted in the induction of p15(INK4B) and p16(INK4A), reactivating the EGFR-dependent senescence program. Importantly, TGF-beta-mediated EMT did not take place when cellular senescence programs were activated by either ZEB knockdown or the activation of wild-type p53 function. Thus, senescence checkpoint functions activated by EGFR and p53 may be evaded through the induction of ZEB, thereby allowing the expansion of an EMT-competent unique cellular subpopulation, providing novel mechanistic insights into the role of ZEB in esophageal carcinogenesis.
Ohashi
Shinya
S
Gastroenterology Division, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Natsuizaka
Mitsuteru
M
Wong
Gabrielle S
GS
Michaylira
Carmen Z
CZ
Grugan
Katharine D
KD
Stairs
Douglas B
DB
Kalabis
Jiri
J
Vega
Maria E
ME
Kalman
Ross A
RA
Nakagawa
Momo
M
Klein-Szanto
Andres J
AJ
Herlyn
Meenhard
M
Diehl
J Alan
JA
Rustgi
Anil K
AK
Nakagawa
Hiroshi
H
D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D016922:Cellular Senescence; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000235:genetics / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004947:Esophagus / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1
D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C495901:TP53 protein, human; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D016159:Tumor Suppressor Protein p53; C486307:ZEB1 protein, human; C492363:ZEB2 protein, human; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; D008156:Luciferases; C512478:EGFR protein, human; D066246:ErbB Receptors; D019098:Telomerase