Adenoviral transduction of human osteoblastic cell cultures. A new perspective for gene therapy of bone diseases

This article confirms the susceptibility of osteoblastic cells to adenoviral transduction. Osteoblasts were harvested from human cancellous bone. Cells were transduced, using various amounts of adenoviral vectors carrying the cDNA encoding interleukin-1 receptor antagonist (IL-1Ra), or the marker genes β-galactosidase and luciferase. Expression of the transgenes and the biological activity of IL-1Ra produced by gene transfer were measured quantitatively in a time-course by ELISA. The rate of transduction was 100% after exposure to 1 x 10⁷ infective particles of adeno-LacZ. No expression of IL-1 Ra was seen after transduction with adeno-IL-1Ra at titers of 1x10⁴ and less. However, after transduction at titers of 1 x10⁷, infective particles cells expressed IL-1Ra consistently for 72 days, with levels up to 1 μg IL-1Ra/1 x 10⁶ cells/48 hours. None of the control samples expressed detectable levels of IL-1Ra. The biological activity of the transgenic IL-1Ra was demonstrated by its ability to suppress successfully IL-1-induced nitric oxide synthesis by rabbit articular chondrocytes. After transduction with 1 x10⁷ infective particles of the adeno-luciferase vector, up to 81,000 Units transgenic luciferase/x 10⁶ osteoblastic cells were measured 2 days after gene transfer. Our results show that adenovirus transduces osteoblastic cells at a high rate in vitro.