756. Distinct Classes of Proteasome-Modulating Agents Cooperatively Augment Recombinant Adeno-Associated Virus Type 2 and Type 5-Mediated Transduction from the Apical Surface of Human Airway Epithelia

Abstract

Top of pageAbstract Tripeptidyl aldehyde proteasome inhibitors have been shown to effectively increase viral capsid ubiquitination and transduction of recombinant adeno-associated virus (rAAV) type 2 and 5 serotypes. In the present study, we have characterized a second class of proteasome-modulating agents (anthracycline derivatives) for their ability to induce rAAV transduction. The anthracycline derivatives doxorubicin and aclarubicin were chosen for analysis because they have been shown to interact with the proteasome through a mechanism distinct from that of tripeptidyl aldehydes. Our studies demonstrated that doxorubicin and aclarubicin also significantly augmented rAAV transduction in airway cell lines and polarized human airway epithelia, human bronchial xenografts, and mice lungs. Both tripeptidyl aldehyde and anthracycline proteasome-modulating agents similarly augmented nuclear accumulation of rAAV in A549 and IB3 airway cell lines but did not directly enhance the efficiency of second- strand synthesis for AAV genome conversion. However, these two cell types demonstrated cell specificity in terms of the ability of LLnL or doxorubicin to augment rAAV transduction. Interestingly, the combined administration of LLnL and doxorubicin resulted in substantially increased transduction (>2000 fold) following apical infection of human polarized epithelia with either rAAV-2 or rAAV-5. In summary, the cell-type specificity of LLnL and doxorubicin to induce rAAV transduction, together with the ability of these compounds to synergistically enhance rAAV transduction in polarized airway epithelial induction, suggest that these two classes of compounds likely modulate different proteasome functions that affect rAAV transduction. Findings from this study provide new insights into how modulation of the proteasome function can be used to augment rAAV transduction in airway epithelia for gene therapy of cystic fibrosis.