Efficient gene transfer into lymphoma cells using adenoviral vectors combined with lipofection

Tumor cells, such as lymphoma cells, are possible targets for gene therapy. In general, gene therapeutic approaches require efficient gene transfer to host cells and sufficient transgene expression, However, lymphoma cells pr eviously have been demonstrated to be resistant to most of the currently av ailable gene transfer methods. The aim of this study was to analyze various methods for transfection of lymphoma cells and to improve the efficiency o f gene delivery. In accordance with previously published reports, lymphoma cells were demonstrated to be resistant to lipofection and electroporation. In contrast, we present an improved adenoviral protocol leading to highly efficient gene transfer to lymphoma cell lines derived from B cells as well as primary lymphoma cells being achieved with an adenoviral vector system encoding the p-galactosidase protein. At a multiplicity of infection of 200 , up to 100% of Daudi cells and Raji cells and 70% of OCI-Ly8-LAM53 cells c ould be transfected. Even at high adenoviral concentrations, no marked toxi city was observed, and the growth characteristics of the lymphoma cell line s were not impaired. The transfection rates in primary cells derived from s ix patients with non-Hodgkin's lymphoma were 30-65%, respectively. Transfec tion efficiency could be further increased by addition of cationic liposome s to adenoviral gene transfer. Furthermore, we examined the expression of t he Coxsackie-adenoviral receptor (CAR) and the integrin receptors on the ly mphoma cell surface. Flow cytometric analysis showed that 88% of Daudi cell s, 69% of Raji cells, and 6% of OCI-Ly8-LAM53 cells expressed CAR on the ce ll surface. According to our data, adenoviral infection of lymphoma cells s eems to be mediated by CAR. In contrast, integrin receptors are unlikely to play a major role, because lymphoma cells were negative for alpha(nu)beta( 3)-integrins and negative for alpha(nu)beta(5)-integrins. In conclusion, th is study demonstrates that B-lymphoma cell lines and primary lymphoma cells can be efficiently transfected using an adenoviral vector system. By addin g cationic liposomes, the efficiency of adenoviral gene transfer to primary tumor cells could be further improved. This protocol may have an impact on the use of lymphoma cells in cancer gene therapy.