Integrin clipping: A novel adhesion switch?

During human prostate cancer progression, the majority of normally expressed integrins are suppressed with the exception of the α6, α3, and β1 integrins. We have shown that in prostate cancer, the α6 integrin is found paired with the β1 integrin and that a novel form of the α6 integrin that lacks a large portion of the extracellular domain (α6p) exists. The α6pβ1 integrin is found in human prostate cancer tissue specimens as well as tissue culture cell lines and is formed on the cell surface. This review discusses the mechanism of α6pβ1 production and the potential functions of this integrin variant. Our current working model predicts that the α6pβ1 integrin maintains the intracellular cytoskeletal connections associated with the heterodimer while allowing for an alteration in cell adhesion. The mechanism provides a selective advantage for cancer cell metastasis.