Induction of Apoptosis using Gene Therapy in the Treatment of Cancer

Abstract

Gene therapy is the treatment of a genetic disease through the insertion of normal or genetically altered genes into cells in order to replace or make up for the non-functional or missing genes. A major application of gene therapy is the induction of apoptosis to inhibit metastases or cure cancer. Besides the identification of the target site, the choice of a suitable vector system for gene delivery is also critical for the realization of gene therapy. While ribozyme mediated induction of apoptosis has an advantage of maintaining regulated expression level of the endogenous gene, antisense therapy suffers a disadvantage of destruction of the oligonucleotides by DNase. The use of siRNA, a novel approach in the field of gene therapy, is limited by their degradation in blood and extracellular fluids. This review discusses the problems associated with the application of the established methods for treatment of cancer viz. surgery, chemotherapy, radiotherapy, and laser therapy. Further, the efficacy of the various strategies for the induction of apoptosis via antisense oligonucleotides, ribozyme, siRNA, and adenoviruses, based on clinical trials and experiments on animal models have been evaluated. Despite some success in this field, some challenges regarding the pathogenecity of viral vectors and transfection efficiency of non viral vectors still remains unanswered.