Focal Adhesion Kinase Activated by β4 Integrin Ligation to mCLCA1 Mediates Early Metastatic Growth

Mossaad Abdel-Ghany,Hung-Chi Cheng,Randolph C Elble,Bendicht U Pauli

doi:10.1074/jbc.m205307200

Mossaad Abdel-Ghany, Hung-Chi Cheng + Show 2 more

Open Access

https://doi.org/10.1074/jbc.m205307200

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Abstract

Early metastatic growth occurs at sites of vascular arrest of blood-borne cancer cells and is entirely intravascular. Here we show that lung colonization by B16-F10 cells is licensed by beta(4) integrin adhesion to the mouse lung endothelial Ca(2+)-activated chloride channel protein mCLCA1. In a manner independent of Met, beta(4) integrin-mCLCA1-ligation leads to complexing with and activation of focal adhesion kinase (FAK) and downstream signaling to extracellular signal-regulated kinase (ERK). FAK/ERK signaling is Src-dependent and is interrupted by adhesion blocking antibodies and by dominant-negative (dn)-FAK mutants. Levels of ERK activation in B16-F10 cells transfected with wild-type or mutant FAK are closely associated with rates of proliferation and bromodeoxyuridine (BrdUrd) incorporation of tumor cells grown in mCLCA1-coated dishes, the ability to form tumor cell colonies on CLCA-expressing endothelial cell monolayers, and the extent of pulmonary metastatic growth. Parallel with the transfection rates, B16-F10 cells transfected with dn-FAK mutants and injected intravenously into syngeneic mice generate approximately half the number and size of lung colonies that vector-transfected B16-F10 cells produce. For the first time, beta(4) integrin ligation to its novel CLCA-adhesion partner is shown to be associated with FAK complexing, activation, and signaling to promote early, intravascular, metastatic growth.

Highlights

Hematogenous metastases originate from tumor cells arrested in the vasculature of select target organs
Levels of extracellular signal-regulated kinase (ERK) activation in B16-F10 cells transfected with wild-type or mutant focal adhesion kinase (FAK) are closely associated with rates of proliferation and bromodeoxyuridine (BrdUrd) incorporation of tumor cells grown in mCLCA1-coated dishes, the ability to form tumor cell colonies on CLCA-expressing endothelial cell monolayers, and the extent of pulmonary metastatic growth
Intrigued by studies in a novel pulmonary metastasis model that allowed the in situ tracking of blood-borne cancer cells in perfused rodent lungs and the finding that lung metastases arose exclusively from endothelial cell-bound tumor cells by intravascular growth [16], we explored whether the ␤4-mCLCA1 adhesion by activating distinct, growth-promoting signaling pathways could account for the observed intravascular tumor cell proliferation

Summary

Introduction

Hematogenous metastases originate from tumor cells arrested in the vasculature of select target organs. Downstream of FAK the extracellular signalregulated kinase (ERK) was activated to promote tumor cell proliferation on surfaces coated with recombinant mCLCA1 and on bovine aortic endothelial cells (BAEC) that constitutively express bCLCA2 protein [5].

Results

Conclusion