Overexpression of integrin αv promotes human osteosarcoma cell populated collagen lattice contraction and cell migration

Cells attach and interact with the extracellular matrix (ECM) through heterodimeric αβ integrin receptors. Specifically, the promiscuous αvβ3 integrin and the α2β1 integrin receptors engage numerous matrix components to influence cell adhesion, cell motility, and matrix organization. However, the role of av integrin mediating cell-collagen interactions is not clear. In the in vitro cell populated collagen lattice (PCL), a model of cell-matrix interaction, integrin receptors play a role in lattice contraction. To elucidate av integrins' effects on cell-collagen interactions, human osteosarcoma (HOS) cells were transfected with av integrin (av-pcDNA 3.1+). Control HOS cells were transfected with pcDNA 3.1 + vector alone. HOS-av cell PCLs contracted to a greater degree than control HOS cell PCLs (P≤ 0.0001). RT-PCR revealed that HOS-av cells express both β1 and β3 integrins, indicating that αv has the potential to form a partnership with either β1 or β3 integrin. The αvβ3 specific inhibitory antibody LM609 significantly retarded HOS-av cell PCL contraction (P≤0.001), suggesting that αvβ3 promotes enhanced HOS-av cell PCL contraction. When plated on plastic, control HOS cells show greater elongation compared to HOS-av cells. In addition, HOS-av cells migrated faster and to a greater degree than control HOS cells (P≤0.0001). The possibility that enhanced HOS-av cell migration and HOS-av cell PCL contraction was caused by increased myosin ATPase activity was examined. HOS-αv cells showed less myosin ATPase activity than control HOS cells, by an ATP cell contraction bioassay. The enhancement of HOS-av cell migration and lattice contraction appears unrelated to increased myosin ATPase activity. J. Cell. Physiol. 193: 219-224, 2002.