New trends of targeting cancer therapy

The key point in cancer therapy is targeting, i.e. the new therapeutic agents should specifically act on tumor cells meanwhile reducing the cytoxicity to the normal cells. There are some new trends in the design of therapeusis and several of them may be promising strategies. Targeting Gene-Virotherapy of Cancer is the combination of gene therapy and oncolytic virotherapy. This viral vector carrying therapeutic gene is under the control of one tumor-specific promoter to obtain restricted replication and expression of gene in tumor cells. Using two tandem promoters and two compensative/synergic genes will achieve better curative effect. To antibody therapy, large quantitive expression of Herceptin or Rituxan by first-generation adenoviral vector will reduce the expensive fee of antibody therapy. RNAi technology-directed gene silencing might allow the silencing of genes that are pathogenic to the host organism. Plasmid vectors or viral vectors have been used as siRNA delivery systems to obtain stable and efficient silencing. Cancer cells may include cancer stem cells with indefinite potential for self-renewal that drive tumorigenesis, studies of cancer stem cells will ultimately yield new approaches to fight cancer. Recently, tumor progression has been recognized as the product of an evolving crosstalk between different cell types within the tumor and its surrounding supporting tissue or tumor stroma. The development of microenvironment-based therapies is now underway. Therapeutic drugs have driven the recent success in the field of molecular cancer therapeutics and many of them target the protein tyrosine kinase or the antiapoptotic proteins. The nanometer technology has received particular attention based on its potential therapeutic effect on tumor cells. When developing new therapies, we need to keep in mind that targeting tumor cells just by one strategy is not likely to be successful. Therefore, the aim should be to combine the strategies.