203 Novel Adeno-Associated Viral (AAV) Vectors for Preferential Targeting of Peripheral Nerve Tumors

Abstract

INTRODUCTION: Definitive treatment for peripheral nerve tumors by surgical excision is associated with significant morbidity. Gene therapy with adeno-associated viral (AAV) vectors is emerging as a promising therapy for these tumors. Directed evolution is a technique that involves applying selective pressure to large libraries of mutated cap genes to bioengineer AAV vectors that selectively bind to and transduce schwannoma tissue. METHODS: Tumor samples were harvested from 8 patients and divided for cell culture. Cultures were infected with novel AAV vector C1, novel AAV vector C5, AAV1, AAV2, and AAV6 at MOIs of 2500, 5000, and 10000 for 3-, 7-, and 14-day periods. GFP fluorescence was used to quantify transduction efficiency of each vector. Statistical analysis was performed with one-way ANOVA and student t test. RESULTS: AAV2 had significantly higher transduction efficiency at 65% +/- 11 compared to all other vectors (p < 0.001). The remaining order of highest transduction efficiency was novel AAV vector C2 at 21% +/- 4, novel AAV vector C5 at 12% +/- 3, AAV1 at 7% +/- 2, and AAV6 at 6% +/- 2. Higher transduction efficiencies were seen at higher MOIs (2500 vs. 5000 vs. 10000) with no significant difference in cell count (2500: 74.25 +/- 25.59. 5000: 105.50 +/- 15.93, 10000: 90.75 +/- 5.74, p = 0.094). Longer post-infection incubation periods (3-day vs. 7-day vs. 14-day) led to higher transduction efficiencies. CONCLUSIONS: AAV2 remains the gold standard for delivery of gene therapy to peripheral nerve tissue. Higher MOIs and longer incubation periods can better differentiate transduction efficiency when comparing multiple AAV vectors without having detrimental effects on cell culture.