In Vitro and In Vivo Models for Evaluation of GDEPT: Quantifying Bystander Killing in Cell Cultures and Tumors

The vectors currently available for gene therapy of cancer rarely achieve expression of therapeutic genes in more than a small fraction of the cells in solid tumors. This makes therapeutic success critically dependent on secondary events, known as bystander effects, by which transgene expression leads to the death of nontransduced tumor cells. An efficient bystander effect has the potential to compensate for spatially nonuniform expression of therapeutic genes, and its optimization is therefore an important goal in gene therapy of cancer. Here, we describe protocols for quantifying bystander effects using in vitro and in vivo experimental models.