Adenovirus-mediated interleukin 3 beta gene transfer by isolated limb perfusion inhibits growth of limb sarcoma in rats

Cytokine gene? transfer using (multiple) intratumoral injections can induce tumor regression in several animal models, but this administration techniq ue limits the use for human gene therapy. In the present studies we describ e tumor growth inhibition of established limb sarcomas after a single isola ted limb perfusion (ILP) with recombinant adenoviral vectors harboring the rat IL-3 beta gene (IG.Ad.CMV.rIL-3 beta). In contrast, a single intratumor al injection or intravenous administration did not affect tumor growth. Dos e-finding studies demonstrated a dose-dependent response with a loss of ant itumor effect below 1 x 10(9) IU of IG.Ad.CMV.rIL-3 beta, Perfusions with a denoviral vectors bearing a weaker promoter (MLP promoter) driving the rIL- 3 beta gene did not result in antitumor responses, suggesting that the rIL- 3 beta -mediated antitumor effect depends on the amount of rIL-3 beta prote in expressed. by the infected cells, Furthermore, it was shown by direct co mparison that ILP with IG.Ad.CMV.rIL-3 beta in the ROS-1 osteosarcoma model is at least as efficient as the established therapy with the combination o f TNF-alpha and melphalan, Treatment with IG.Ad.CMV.rIL-3 beta induced a tr ansient dose-dependent leukocytosis accompanied by an increase in periphera l blood levels of histamine. Leukocyte infiltrations were also histopatholo gically demonstrated in tumors after perfusion. These results demonstrate t hat ILP with recombinant adenoviral vectors carrying the IL-3 beta transgen e inhibits tumor growth in rats and suggest that cytokine gene therapy usin g this administration technique might be beneficial for clinical cancer tre atment.