Experimental Strategies for Combined Suicide and Immune Cancer Gene Therapy: An Overview

Suicide gene therapy systems are characterized by the transfer of therapeutic transgenes, which encode for enzymes of various origins. These enzymes are able to convert nontoxic prodrugs into highly cytotoxic metabolites. Thus, all cells that are transduced by suicide genes will be destroyed when the corresponding prodrug is applied. The cytotoxicity is mostly limited to transduced cells, but nontransduced cells may also be affected by the so-called bystander effect. The bystander effect (1 ) describes the phenomenon that in cell culture only a relatively small amount of cells has to be transduced with the suicide gene to gain complete cell killing upon treatment with the corresponding prodrug.