Gene therapy is a new experimental therapy and defined as the delivery of a therapeutic gene into a cell. Viruses are most often used as delivery vehicles because they have during their evolution developed mechanisms to efficiently introduce their genome into many different cell types. By gene therapy, viruses are modified to deliver a therapeutic gene instead of their genome into cells.
Figure: delivery of green fluorescent protein (GFP) into a cell by a virus. GFP is often used as a marker to detect infection of a cell by a virus. In gene therapy, GFP is replaced by a therapeutic gene.
We have during recent years developed and tested a novel gene therapy strategy for human glioblastoma based on lentiviral vectors delivering a suicide gene. Suicide genes code for an enzyme that turns a non-toxic prodrug into a toxic product and thereby kills the cancer cell. Using different preclinical animal models, we have shown a high transduction efficacy and a highly significant survival benefit for animals treated with this novel therapy .
Figure: Suicide gene therapy with lentiviral vectors and a prodrug in a clinically relevant animal model for human glioblastoma. The therapeutic group (virus + prodrug) shows dramatic reduction in tumour size on MRI compared to control groups. Modified from Huszthy et al., PLOS One 2009. Copyright PLOS One.