Characterization of a novel hybrid vector between M13 phage capsid and double double-stranded AAV (adeno-associated virus) genome, and its application

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Characterization of a novel hybrid vector between M13 phage capsid and double double-stranded AAV (adeno-associated virus) genome, and its application in cancer gene therapyMost of cancer related deaths are linked to the development of metastases, against which traditional therapies are not efficient at targeting. Therefore, it is imperative to find new, safe and systemic approaches able to treat metastatic cancer. The use of viruses for this purpose is an attractive option, with the adeno-associated virus (AAV) being one of the preferred candidates. Despite its good profile, AAV derived vectors still have several drawbacks, such as the generalized pre-existing immunity in the human population, its limited transgene encoding capacity or its complex production protocols. Phage/adeno-associated virus hybrid vectors have been proposed as an alternative option to overcome some major AAV-associated disadvantages. These hybrid vectors have an excellent safety profile linked to their bacteriophage origin and were engineered to specifically target tumours and tumour vasculature after systemic delivery. They have a substantially higher transgene packaging capacity than AAVs and their production is simpler and easily scalable. They also have been proven to be able to cross the blood brain barrier, expanding their application to tumours or metastases occurring in the brain. The last generation of these vectors is based on a phagemid system, that was further modified to enhance the endosomal escape and reduce the unspecific binding to extracellular molecules. Also, their genome has been designed to generate a self-complementary transgene to overcome the single stranded to double stranded DNA synthesis step, a recognized major bottleneck in AAV and derived systems. Here, I will first characterize the last generation of the last generation of PAAV hybrid vectors in vitro. Then, I will evaluate the efficiency of these vectors encoding three different therapeutic transgene candidates: interleukins IL12, IL15 and tumor necrosis factor alpha (TNF) in an ex vivo setting. Next, the most suitable and efficient vector will be selected to target metastatic cancer established in immunocompetent mice from 4T1 mouse mammary tumour cells and B16F10 mouse melanoma cells.