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Hum Gene Ther Methods. 2017 Feb;28(1):49-59. doi: 10.1089/hgtb.2016.089.

Efficient Gene Delivery and Expression in Pancreas and Pancreatic Tumors by Capsid-Optimized AAV8 Vectors.

Author information

1
1 Department of Anatomy and Cell Biology, University of Florida College of Medicine , Gainesville, Florida.
2
2 Department of Veterinary Medicine, University of Florida College of Medicine , Gainesville, Florida.
3
3 Department of Ophthalmology, University of Florida College of Medicine , Gainesville, Florida.
4
4 Department of Medicine, University of Florida College of Medicine , Gainesville, Florida.
5
5 Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida.

Abstract

Despite efforts to use adeno-associated viral (AAV) vector-mediated gene therapy for treatment of pancreatic ductal adenocarcinoma (PDAC), transduction efficiency remains a limiting factor and thus improvement of AAV delivery would significantly facilitate the treatment of this malignancy. Site-directed mutagenesis of specific tyrosine (Y) residues to phenylalanine (F) on the surface of various AAV serotype capsids has been reported as a method for enhancing gene transfer efficiencies. In the present studies, we determine whether Y-to-F mutations could also enhance AAV8 gene transfer in the pancreas to facilitate gene therapy for PDAC. Three different Y-to-F mutant vectors (a single-mutant, Y733F; a double-mutant, Y447F+Y733F; and a triple-mutant, Y275F+Y447F+Y733F) and wild-type AAV8 (WT-AAV8) were administered by intraperitoneal or tail-vein routes to KrasG12D+/-, KrasG12D+/-/Pten+/-, and wild-type mice. The transduction efficiency of these vectors expressing the mCherry reporter gene was evaluated 2 weeks post administration in pancreas or PDAC and correlated with viral genome copy numbers. Our comparative and quantitative analyses of the transduction profiles demonstrated that the Y-to-F double-mutant exhibited the highest mCherry expression in pancreatic tissues (range 45-70%) compared with WT-AAV8 (7%; p < 0.01). We also detected a 7-fold higher level of vector genome copy numbers in normal pancreas following transduction with the double-mutant AAV8 compared with WT-AAV8 (10,285 vs. 1,500 vector copies/μg DNA respectively, p < 0.05). In addition, we observed that intraperitoneal injection of the double-mutant AAV8 led to a 15-fold enhanced transduction efficiency as compared to WT-AAV8 in mouse PDAC, with a corresponding ∼14-fold increase in vector genome copy numbers (26,575 vs. 2,165 copies/μg DNA respectively, p < 0.05). These findings indicate that the Y447+Y733F-AAV8 leads to a significant enhancement of transduction efficiency in both normal and malignant pancreatic tissues, suggesting the potential use of this vector in targeting pancreatic diseases in general, and PDAC in particular.

KEYWORDS:

AAV8; adeno-associated virus; gene therapy; pancreatic cancer

PMID:
28125909
PMCID:
PMC5314986
DOI:
10.1089/hgtb.2016.089
[Indexed for MEDLINE]
Free PMC Article

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