An adenoviral vector expressing human adenovirus 5 and 3 fiber proteins for targeting heterogeneous cell populations.
ABSTRACT Human adenovirus serotype 5 (HAdV-5) attaches to its primary receptor, the coxsackie and adenovirus receptor (CAR) as the first step of infection. However, CAR expression decreases as tumors progress, thereby diminishing the utility of HAdV-5-based vectors for cancer therapy. In contrast, many aggressive tumor cells highly express CD46, a cellular receptor for HAdV-3. We hypothesized that a mosaic HAdV vector, containing two kinds of fiber proteins, would provide extensive transduction in a heterogeneous population of tumor cells with varying expression levels of HAdV receptors. We therefore generated a fiber-mosaic HAdV vector displaying both a chimeric HAdV-3 fiber and the HAdV-5 fiber protein. We verified the structural integrity of purified viral particles and confirmed that the fiber-mosaic HAdV vector has expanded tropism. We conclude that the use of fiber-mosaic HAdV vectors is a promising approach for transducing a heterogeneous cell population with different expression levels of adenovirus receptors.
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ABSTRACT: The gene therapy field is currently limited by the lack of vehicles that permit efficient gene delivery to specific cell or tissue subsets. Native viral vector tropisms offer a powerful platform for transgene delivery but remain nonspecific, requiring elevated viral doses to achieve efficacy. In order to improve upon these strategies, our group has focused on genetically engineering targeting domains into viral capsid proteins, particularly those based on adenovirus serotype 5 (Ad5). Our primary strategy is based on deletion of the fiber knob domain, to eliminate broad tissue specificity through the human coxsackie-and-adenovirus receptor (hCAR), with seamless incorporation of ligands to re-direct Ad tropism to cell types that express the cognate receptors. Previously, our group and others have demonstrated successful implementation of this strategy in order to specifically target Ad to a number of surface molecules expressed on immortalized cell lines. Here, we utilized phage biopanning to identify a myeloid cell-binding peptide (MBP), with the sequence WTLDRGY, and demonstrated that MBP can be successfully incorporated into a knob-deleted Ad5. The resulting virus, Ad.MBP, results in specific binding to primary myeloid cell types, as well as significantly higher transduction of these target populations ex vivo, compared to unmodified Ad5. These data are the first step in demonstrating Ad targeting to cell types associated with inflammatory disease.PLoS ONE 01/2012; 7(5):e37812. · 4.09 Impact Factor
Article: An adenovirus vector incorporating carbohydrate binding domains utilizes glycans for gene transfer.[show abstract] [hide abstract]
ABSTRACT: Vectors based on human adenovirus serotype 5 (HAdV-5) continue to show promise as delivery vehicles for cancer gene therapy. Nevertheless, it has become clear that therapeutic benefit is directly linked to tumor-specific vector localization, highlighting the need for tumor-targeted gene delivery. Aberrant glycosylation of cell surface glycoproteins and glycolipids is a central feature of malignant transformation, and tumor-associated glycoforms are recognized as cancer biomarkers. On this basis, we hypothesized that cancer-specific cell-surface glycans could be the basis of a novel paradigm in HAdV-5-based vector targeting. As a first step toward this goal, we constructed a novel HAdV-5 vector encoding a unique chimeric fiber protein that contains the tandem carbohydrate binding domains of the fiber protein of the NADC-1 strain of porcine adenovirus type 4 (PAdV-4). This glycan-targeted vector displays augmented CAR-independent gene transfer in cells with low CAR expression. Further, we show that gene transfer is markedly decreased in cells with genetic glycosylation defects and by inhibitors of glycosylation in normal cells. These data provide the initial proof-of-concept for HAdV-5 vector-mediated gene delivery based on the presence of cell-surface carbohydrates. Further development of this new targeting paradigm could provide targeted gene delivery based on vector recognition of disease-specific glycan biomarkers.PLoS ONE 01/2013; 8(2):e55533. · 4.09 Impact Factor