Combining CRAd and killing gene armed Adenovirus including TRAIL increase anti-cancer effect

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To overcome low efficiency of gene therapy, we tried to combine Adenoviral vector including killing gene and CRAd (conditionally replicating adenovirus). CRAd show oncolytic action in cancer cells with abnormal Rb activity and help replication of E1-deleted Adenovirus including killing gene. We hypothesized that conventional E1-deleted adenovirus can replicate competently when co-transfected with a CRAd to selectively supply E1 in tumors by combining with CRAd and Adenovirus. As combining with CRAd and Adenovirus carrying TRAIL, we expected double effect that is the increase of killing gene expression in cancer cell and tumor killing effect. Additionally, we expected that this combination strategy could extend to multi-targeting cancer therapy.
 >First, to identify any increase of gene expression in conventional E1-deleted adenovirus, we tested combinational application with CRAd and Adeno-luciferase in head and neck cancer cell line and observed a big increase of luciferase activity by 10-50 times than transfection with Adeno-luciferase alone. Next, we investigated anti-cancer-effect of combination with Ad-TRAIL and CRAd, comparing with single transfection of Adeno -TRAIL and observed that combining CRAd and Adeno-TRAIL showed the increasing sub-G1 above 30 fold by PI staining than any single application in head and neck cancer cell lines.
 >When Co-transfected with CRAd, increasing expression of TRAIL by 3-5-fold than transduction with Adeno-TRAIL alone. These results represents that this combination with CRAd and Adenovirus increased killing gene transfer rate and enhanced its anti-tumor effect.
 >As on going experiment, we checked multi-targeting was also effective. We tried multi targeting gene therapy by combining with E1-deleted Adenovirus and CRAd. We combined Adeno-luciferase plus Adeno-LacZ plus Adeno-GFP and CRAd. We checked an activity of each gene. All of these reporter genes were expressed well without interruption among them. From these result, we expected that multi-targeting gene therapy could be possible. However, important things to do multi targeting gene therapy is finding suitable killing gene.