Real-time imaging of αv integrin molecular dynamics in osteosarcoma cells in vitro and in vivo

αv Integrin is involved in various steps of cancer metastasis. In this report, we describe real-time imaging of αv integrin molecular dynamics in human 143B osteosarcoma cells in vitro and in vivo. We first generated osteosarcoma cells expressing αv integrin green fluorescent protein (GFP) by transfection of an αv integrin GFP fusion vector (pCMV6-AC-ITGAV-GFP) into 143B cells. Confocal laser-scanning microscopy demonstrated that αv integrin immunofluorescence staining co-localized with αv integrin-GFP fluorescence in 143B cells. When αv integrin-GFP-expressing 143B osteosarcoma cells were seeded on a dish coated with fibronectin, which is bound by αv integrin, punctate αv integrin-GFP was observed by confocal laser-scanning microscopy. When the 143B αv integrin-GFP cells were seeded onto uncoated plastic, αv integrin-GFP was diffuse within the cells. When αv integrin-GFP 143B osteosarcoma cells (1×10(6)) were orthotopically transplanted into the tibia of nude mice, the cells aligned along the collagen fibers within the tumor and had punctuate expression of αv integrin-GFP. In the orthotopic model, the invading osteosarcoma cells had punctate αv integrin-GFP in the muscle tissue at the primary tumor margin. These results show that αv integrin-GFP enables the imaging of the molecular dynamics of αv integrin in osteosarcoma cells in vitro and in vivo.