Coordinated functions of E-cadherin and transforming growth factor beta receptor II in vitro and in vivo.
In epithelial cells, E-cadherin plays a key role in cell-cell adhesion, and loss of E-cadherin is a hallmark of tumor progression fostering cancer cell invasion and metastasis. To examine E-cadherin loss in squamous cell cancers, we used primary human esophageal epithelial cells (keratinocytes) as a platform and retrovirally transduced wild-type and dominant-negative forms of E-cadherin into these cells. We found decreased cell adhesion in the cells expressing dominant-negative E-cadherin, thereby resulting in enhanced migration and invasion. To analyze which molecular pathway(s) may modulate these changes, we conducted microarray analysis and found up-regulation of transforming growth factor beta receptor II (TbetaRII) in the wild-type E-cadherin-overexpressing cells, which was confirmed by real-time PCR and Western blot analyses. To investigate the in vivo relevance of this finding, we analyzed tissue microarrays of paired esophageal squamous cell carcinomas and adjacent normal esophagus, and we could show a coordinated loss of E-cadherin and TbetaRII in approximately 80% of tumors. To determine if there may be an E-cadherin-dependent regulation of TbetaRII, we show the physical interaction of E-cadherin with TbetaRII and that this is mediated through the extracellular domains of E-cadherin and TbetaRII, respectively. In addition, TbetaRI is recruited to this complex. When placed in the context of three-dimensional cell culture, which reflects the physiologic microenvironment, TbetaRII-mediated cell signaling is dependent upon intact E-cadherin function. Our results, which suggest that E-cadherin regulates TbetaRII function, have important implications for epithelial carcinogenesis characterized through the frequent occurrence of E-cadherin and TbetaRII loss.
Andl
Claudia D
CD
Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA 19104, USA. anil2@mail.med.upenn.edu
Fargnoli
Brenton B
BB
Okawa
Takaomi
T
Bowser
Mark
M
Takaoka
Munenori
M
Nakagawa
Hiroshi
H
Klein-Szanto
Andres
A
Hua
Xianxin
X
Herlyn
Meenhard
M
Rustgi
Anil K
AK
D015820:Cadherins / Q000502:physiology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D015536:Down-Regulation; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D004938:Esophageal Neoplasms / Q000473:pathology; D004947:Esophagus / Q000166:cytology / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D018874:Spheroids, Cellular; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology; D015854:Up-Regulation
D015820:Cadherins; D018125:Receptors, Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II