HIGH-EFFICIENCY STABLE GENE-TRANSFER OF ADENOVIRUS INTO MAMMALIAN-CELLS USING IONIZING-RADIATION

We report a novel method for targeting adenovirus-mediated gene delive ry, By irradiating mammalian cells prior to adenoviral transduction, a denoviral gene transfer is greatly improved and the adenoviral genome integrates into cellular DNA, In this work, human and rodent cell line s were irradiated and subsequently transduced with the adenovirus vect or Ad5CMVlacZ. Initial levels of transduction were as much as 40-fold higher in irradiated cells, and this improvement in transduction was r adiation dose dependent, The duration of lacZ expression in irradiated cells was also much longer than in nonirradiated cells and reached a plateau after 21 days, At doses of 7 Gy, long-term (<50 day) expressio n of lacZ could be detected in 15% of cells by flow cytometry, This lo ng-lasting expression of lacZ was due to viral DNA integration into th e host genome, Thus, pretreatment of cells with ionizing radiation imp roves both immediate transduction efficiency and duration of transgene expression, This may lead to the development of new protocols combini ng radiation and gene therapy in treating human malignancy.