Augmented transgene expression in transformed cells using a parvoviral hybrid vector

Area of Science:

• Oncology
• Virology
• Gene Therapy

Background:

• Autonomous parvoviruses exhibit natural oncotropism, influenced by viral genetic elements governing gene expression and replication.
• Adeno-associated virus (AAV) vectors are widely used for gene delivery but can be improved for tumor-specific targeting.

Purpose of the Study:

• To construct and evaluate a hybrid parvovirus vector with enhanced oncotropism for cancer gene therapy.
• To assess the vector's efficiency in gene transduction and selective tumor cell killing.

Main Methods:

• A hybrid vector was engineered using the H1 parvovirus expression cassette and adeno-associated virus 2 (AAV2) components, packaged into AAV2 capsids.
• Gene transduction efficiency was compared between the hybrid vector and standard AAV2 vectors under various stimulation conditions (adenovirus coinfection, irradiation, genotoxic agents).
• Selective tumor cell killing was demonstrated using a prodrug-converting enzyme, and in vivo studies were conducted in a syngeneic rat model.

Main Results:

• The hybrid vector showed stimulated gene transduction, often exceeding the efficiency of standard AAV2 vectors.
• Selective enhancement of transgene expression was observed in tumor cells compared to non-transformed cells.
• In vivo studies revealed preferential gene expression in tumor tissue over normal liver tissue.
• Distinct tumor cell line tropisms were observed for the H1 and hybrid vectors, suggesting capsid-dependent viral tropism.

Conclusions:

• The developed H1/AAV2 hybrid vector exhibits improved oncotropism and gene transduction efficiency.
• This vector holds promise for targeted cancer gene therapy, enabling selective tumor cell killing and preferential gene expression in vivo.
• Viral capsid determinants play a crucial role in dictating vector tropism for specific cell types.