759. The DNA Minor Groove Binding Agents Hoechst 33258 and 33342 Enhance Recombinant Adeno-Associated Virus (rAAV) Transgene Expression

Abstract

Recombinant adeno-associated viruses (rAAV) are commonly used in pre-clinical and clinical gene transfer studies. The relatively slow kinetics of rAAV transgene expression, however, complicates in vitro and in vivo experiments. Accelerating the kinetics of rAAV transgene expression would extend the applications of rAAV for gene transfer and facilitate the determination of vector biological activity in vitro. We found that the DNA minor groove binding agents, Hoechst 33258 and 33342, enhance rAAV gene expression. Hoechst 33258 or 33342 increase both the level of reporter gene expression and the population of transgene expressing cells. We found that Hoechst 33258 and 33342 augment rAAV gene expression in different cell types and in a concentration dependent manner. Hoechst 33258 or 33342 enhanced gene expression for rAAV-1, rAAV-2 and rAAV-5. Hoechst 33258 and 33342 mediated enhancement of rAAV gene expression correlated with an increase in S phase and G2/M phases of the cell cycle. Our data revealed that two different, although related, DNA binding drugs effect rAAV gene expression in a similar manner, suggesting that a common pathway is involved. Our results suggest that Hoechst 33258 and 33342 are potential enhancer drugs for the gene expression and might be useful for gene therapy applications.