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

α_v Integrin is involved in various steps of cancer metastasis. In this report, we describe real-time imaging of α_v integrin molecular dynamics in human 143B osteosarcoma cells in vitro and in vivo. We first generated osteosarcoma cells expressing α_v integrin green fluorescent protein (GFP) by transfection of an α_v integrin GFP fusion vector (pCMV6- AC-ITGAV-GFP) into 143B cells. Confocal laser-scanning microscopy demonstrated that α_v integrin immunofluorescence staining co-localized with α_v integrin-GFP fluorescence in 143B cells. When α_v integrin-GFP-expressing 143B osteosarcoma cells were seeded on a dish coated with fibronectin, which is bound by α_v integrin, punctate α_v integrin-GFP was observed by confocal laser-scanning microscopy. When the 143B α_v integrin-GFP cells were seeded onto uncoated plastic, α_v integrin-GFP was diffuse within the cells. When α_v integrin-GFP 143B osteosarcoma cells (1×106) were orthotopically transplanted into the tibia of nude mice, the cells aligned along the collagen fibers within the tumor and had punctuate expression of α_v integrin-GFP. In the orthotopic model, the invading osteosarcoma cells had punctate α_v integrin-GFP in the muscle tissue at the primary tumor margin. These results show that α_v integrin-GFP enables the imaging of the molecular dynamics of α_v integrin in osteosarcoma cells in vitro and in vivo.