THE PRESENCE OF HUMAN COXSACKIEVIRUS AND ADENOVIRUS RECEPTOR IS ASSOCIATED WITH EFFICIENT ADENOVIRUS-MEDIATED TRANSGENE EXPRESSION IN HUMAN-MELANOMA CELL-CULTURES

Adenovirus (AdV)-mediated gene expression of immune stimulators repres ents a valuable in vivo approach for gene therapy of human cancer. The expression level of the therapeutic gene is of crucial importance for the efficacy of this type of treatment. Entry of AdV is dependent on the primary adenovirus receptor CAR and the secondary AdV receptor ide ntified earlier to be a member of the integrin family of surface molec ules. We have analyzed 14 different human melanoma cell cultures from different stages together with one melanoma cell line for their AdV-me diated transduction and expression efficiency. Recombinant viruses at various concentrations were used for expression of the B7-1 costimulat ory molecule under the control of different promoters and the expressi on levels of B7-1 were analyzed by flow cytometry, AdV-mediated IL-12 expression was measured using a commercial ELISA, Levels of transgene expression were compared with the expression levels of HCAR, the alpha (v)beta(3) and alpha(v)beta(5) integrins, and HLA class I. In 4 of 14 cell cultures tested, the presence of the primary virus receptor CAR w as associated with the high transduction efficiency phenotype when usi ng the B7-1- and IL-12-expressing viruses at a relatively low multipli city of infection (MOI) of 50, Immunohistochemistry on cryosections fr om the original biopsies yielded a strong signal specific for CAR. In contrast, cell cultures expressing low or undetectable levels of CAR n eeded a 20- to 40-fold higher viral input to show comparable expressio n level of B7-1 or IL-12. Expression levels of the transgenes hardly v aried when using different promoters and no association was observed w ith the presence or absence of HLA class I molecules or with the expre ssion levels of integrins.