E-cadherin-mediated adhesion inhibits ligand-dependent activation of diverse receptor tyrosine kinases

Area of Science:

• Cell Biology
• Molecular Oncology
• Cancer Signaling

Background:

• E-cadherin is a crucial adhesion protein and tumor suppressor frequently silenced in various cancers.
• The precise mechanisms by which E-cadherin regulates signaling pathways, particularly in an adhesion-dependent manner, remain largely unelucidated.

Purpose of the Study:

• To investigate the adhesion-dependent regulation of receptor tyrosine kinases (RTKs) by E-cadherin.
• To elucidate how E-cadherin influences the ligand-dependent activation of RTKs and other signaling receptors.

Main Methods:

• Investigated E-cadherin's effect on ligand-dependent activation of various receptor tyrosine kinases (RTKs) and G protein-coupled receptors (GPCRs).
• Assessed changes in receptor mobility and ligand-binding affinity associated with E-cadherin expression.
• Utilized transfection of E-cadherin into cancer cell lines with downregulated endogenous E-cadherin.

Main Results:

• E-cadherin negatively regulates ligand-dependent activation of divergent RTKs in an adhesion-dependent manner.
• This regulation is associated with decreased receptor mobility and ligand-binding affinity.
• E-cadherin forms complexes with EGFR, dependent on its extracellular domain, independent of beta-catenin or p120-catenin binding.
• E-cadherin did not affect constitutively active RTKs or GPCRs (LPA, muscarinic receptors).

Conclusions:

• E-cadherin's adhesion-dependent negative regulation of RTKs represents a novel mechanism for controlling RTK signaling.
• Abrogation of E-cadherin-mediated RTK regulation may contribute to aberrant RTK activation observed in tumors.
• Restoring E-cadherin function could be a therapeutic strategy for cancers with dysregulated RTK signaling.