Abstract
Inactivation of the transforming growth factor-β (TGF-β) pathway occurs often in malignancies of the gastrointestinal (GI) system. However, only a fraction of sporadic GI tumors exhibit inactivating mutations in early stages of cancer formation, suggesting that other mechanisms play a critical role in the inactivation of this pathway. Here, we show a wide range of GI tumors, including those of the stomach, liver and colon in elf+/- and elf+/-/Smad4+/- mutant mice. We found that embryonic liver fodrin (ELF), a β-Spectrin originally identified in endodermal stem/ progenitor cells committed to foregut lineage, possesses potent antioncogenic activity and is frequently inactivated in GI cancers. Specifically, E-cadherin accumulation at cell-cell contacts and E-cadherin-β-catenin-dependent epithelial cell-cell adhesion is disrupted in elf+/- Smad4 +/- mutant gastric epithelial cells, and could be rescued by ectopic expression of full-length elf, but not Smad3 or Smad4. Subcellular fractionation revealed that E-cadherin is expressed mainly at the cell membrane after TGF-β stimulation. In contrast, elf+/- /Smad4+/- mutant tissues showed abnormal distribution of E-cadherin that could be rescued by overexpression of ELF but not Smad3 or Smad4. Our results identify a group of common lethal malignancies in which inactivation of TGF-β signaling, which is essential for tumor suppression, is disrupted by inactivation of the ELF adaptor protein.
Original language | English (US) |
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Pages (from-to) | 1871-1886 |
Number of pages | 16 |
Journal | Oncogene |
Volume | 25 |
Issue number | 13 |
DOIs | |
State | Published - Mar 23 2006 |
Keywords
- E-cadherin
- ELF
- Gastrointestinal cancer
- Smad4
- Spectrin
ASJC Scopus subject areas
- Molecular Biology
- Genetics
- Cancer Research