Requirement of the integrin β3 subunit for carcinoma cell spreading or migration on vitronectin and fibrinogen

Abstract

FG human pancreatic carcinoma cells use integrin αvβ5 as their primary vitronectin receptor since they feil to express integrin αvβ3. These cells are unable to form focal contacts, spread, or migrate on vitronectin but readily do so on collagen in a β1 integrin-dependent manner. Transfection of FG cells with a cDNA encoding the integrin β3 subunit results in the surface expression of a functional integrin αvβ3 heterodimer providing these cells with novel adhesive and biological properties. Specifically, FG cells expressing β3 acquire the capacity to attach and spread on vitronectin as well as fibrinogen with β3 localization to focal contacts. Moreover, these cells gain the capacity to migrate through a porous membrane in response to either vitronectin or fibrinogen. These results demonstrate that the β3 and γ5 integrin subunits when associated with αv, promote distinct cellular responses to a vitronectin extracellular environment.