Giant cell tumor of bone (GCT) is a bone tumor consisting of numerous multinucleated osteoclastic giant cells involved in bone resorption and neoplastic osteoblast-like stromal cells responsible for tumor growth. The tumor occasionally metastasizes to the lung; however, factors leading to metastasis in this tumor are unknown. The TWIST-1 protein (also referred to as TWIST) has been suggested to be involved in epithelial-mesenchymal transition (EMT) and tumor progression in some cancers. In this study we investigated the functional role of TWIST in GCT cell angiogenesis and migration. Overexpression of TWIST in neoplastic GCT stromal cells significantly increased mRNA and protein expression of VEGF and VEGFR1 in vitro, whereas knockdown of TWIST resulted in decreased VEGF and VEGFR1 expression. A stable cell line with TWIST overexpression resulted in features of EMT including increased cell migration and downregulation of E-cadherin. The results of our study indicate that TWIST may play an important role in angiogenesis and cell migration in GCT.
Matrix Metalloproteinase Activity in the Stromal Cell of Giant Cell Tumor of Bone
