Perturbing gene expression with oligodeoxynucleotides: research and potential therapeutic applications

The ability to block gene function with antisense oligodeoxynucleotides has become an important tool in many research laboratories. Because activation and aberrant expression of proto-oncogenes seems to be an important mechanism in malignant transformation, targeted disruption of these genes and other molecular targets with oligodeoxynucleotides could have significant therapeutic utility as well. In this regard, the potential therapeutic usefulness of oligodeoxynucleotides has been demonstrated in many systems and against several different targets including viruses, oncogenes, proto-oncogenes and an increasing array of cellular genes. These studies in aggregate suggest that synthetic oligomers have the potential to become an important new therapeutic agent for the treatment of cancer in humans. Nevertheless, it is clear that considerable optimization will be required before antisense oligonucleotides will emerge as an effective agent for treating disease in humans. Progress will need to occur on several fronts. Included are issues related to the chemistry of the molecules used: for example, how chemical modification has an impact on uptake, stability, and hybridization efficiency of the synthetic DNA molecule. A clearer understanding of the mechanism of antisense-mediated inhibition, including where such inhibition takes place, will also be required. Finally, cellular "defense" mechanisms, such as increasing transcription of the targeted message, may also be factors to consider in planning effective treatment strategies with these agents. Finally, choice of target is also obviously an important issue.