Versican, a large chondroitin sulfate proteoglycan that binds hyaluronan and is composed of large extracellular matrix aggregates, has been shown to correlate with tumor progression. No studies have examined the roles of versican in chondrosarcoma nor compared them to those of aggrecan. In clinical specimens of human chondromatous tumors, versican expression was significantly increased in malignant tumors, moreover, as the tumor grade increased. To clarify the roles of versican in chondrosarcoma, versican splicing variant 1, variant 3 or only GFP was stably transfected to Swarm rat chondrosarcoma cells with Trap-In System. Forced expression of versican V1 isoform in Swarm rat chondrosarcoma cells induced a marked increase of cell-associated matrix compared to V3-, GFP-transfected or RCS cells. Versican was immunolocalized in a fashion similar to that of hyaluronan and more diffusively than aggrecan. Anchor-dependent and -independent growth was not affected by versican isoform expression, whereas cell motility and migration were significantly enhanced by V1 isoform transfection. Tumors formed in vivo with V1-transfected cells exhibited more myxomatous area and included more spindle shaped cells. These results support the concept that versican has the capacity to form more extensive cell-associated matrix than aggrecan, and the prominent matrix formation alters the cell behavior of chondrosarcoma more aggressively. These observations suggest that versican expression may serve as a marker of tumor grade determination in chondrosarcoma and possibly help to decide on therapeutic targets in higher grades of chondrosarcoma.Versican/PG-M is a large chondroitin sulfate (CS) proteoglycan of the extracellular matrix (ECM) that was initially identified in cultured fibroblasts, 1 and its chicken homolog (called PG-M) was isolated from developing limb buds.2 The core protein of versican consists of N-and C-terminal globular domains (G1 and G3) and two CS attachment domains (CSa and CS-b). The G1 domain of versican binds hyaluronan and the G3 domain consists of lectin-like carbohydrate recognition domain and epidermal growth factor (EGF)-like and complement-binding protein-like domains. Versican is able to regulate many cellular processes including adhesion, proliferation, apoptosis, migration and invasion via the highly negatively charged chondroitin/dermatan sulfate side chains and by interactions of the G1 and G3 domains with other proteins.3,4 Alternative splicing of versican generates at least four isoforms named V0, V1, V2 and V3.5,6 V0 contains two alternatively spliced GAG attachment domains (CS-a and CS-b). In contrast, V1 comprises the CS-b domain only, whereas V2 contains only CS-a domain. The CS-a and CS-b domains are both absent in the V3 isoform. The V0 isoform is particularly prevalent during early embryonic development 7 but less well expressed in adult tissues.8 On the contrary, several pieces of information have become available assigning distinct functions to individual versican isoforms, V1, V2 and V3. The ...