Induction of human epithelial stem/progenitor expansion by FOXM1.
Stem cells are permanent residents of tissues and thought to be targets of cancer initiation. The frequent, and often early, upregulation of the FOXM1 transcription factor in the majority of human cancers suggests that it may participate in the initiation of human tumorigenesis. However, this hypothesis has not been tested. Herein, we show that targeting the ectopic expression of FOXM1 to the highly clonogenic cells of primary human keratinocytes with stem/progenitor cell properties, but not to differentiating cells, caused clonal expansion in vitro. We show, using a functional three-dimensional organotypic epithelial tissue regeneration system, that ectopic FOXM1 expression perturbed epithelial differentiation generating a hyperproliferative phenotype reminiscent of that seen in human epithelial hyperplasia. Furthermore, transcriptional expression analysis of a panel of 28 epithelial differentiation-specific genes reveals a role for FOXM1 in the suppression of epithelial differentiation. This study provides the first evidence that FOXM1 participates in an early oncogenic pathway that predisposes cells to tumorigenesis by expanding the stem/progenitor compartment and deregulating subsequent keratinocyte terminal differentiation. This finding reveals an important window of susceptibility to oncogenic signals in epithelial stem/progenitor cells prior to differentiation, and may provide a significant benefit to the design of cancer therapeutic interventions that target oncogenesis at its earliest incipient stage.
Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Centre for Clinical and Diagnostic Oral Sciences, London, England.
Emilios
E
Gemenetzidis
Daniela
D
Elena-Costea
Eric K
EK
Parkinson
Ahmad
A
Waseem
Hong
H
Wan
Muy-Teck
MT
Teh
D016475:3T3 Cells; D000818:Animals; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000378:metabolism*; D014407:Tumor Cells, Cultured
C107585:FOXM1 protein, human; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors; C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D017475:Receptors, Nerve Growth Factor