The role of antisense oligonucleotides in the wave of genomic information

DNA as therapeutics; an update

Human gene therapy is the introduction of new genetic material into the cells of an individual with the intention of producing a therapeutic benefit for the patient. Deoxyribonucleic acid and ribonucleic acid are used in gene therapy. Over time and with proper oversight, human gene therapy might become an effective weapon in modern medicine's arsenal to help fight diseases such as cancer, acquired immunodeficiency syndrome, diabetes, high blood pressure, coronary heart disease, peripheral vascular disease, neurodegenerative diseases, cystic fibrosis, hemophilia and other genetic disorders. Gene therapy trials in humans are of two types, somatic and germ line gene therapy. There are many ethical, social, and commercial issues raised by the prospects of treating patients whose consent is impossible to obtain. This review summarizes deoxyribonucleic acid-based therapeutics and gene transfer technologies for the diseases that are known to be genetic in origin. Deoxyribonucleic acid-based therapeutics includes plasmids, oligonucleotides for antisense and antigene applications, deoxyribonucleic acid aptamers and deoxyribonucleic acidzymes. This review also includes current status of gene therapy and recent developments in gene therapy research.

Modified concatemeric oligonucleotide complexes: new system for efficient oligonucleotide transfer into mammalian cells

Antisense oligonucleotides and double-stranded small interfering RNAs have become an important instrument for the manipulation of gene expression in molecular biology experiments and a promising tool for the development of gene-targeted therapeutics. One of the main impediments in the use of oligonucleotide-based therapeutics is their poor uptake by target cells. The formation of supramolecular concatemeric complexes by oligonucleotides was shown to promote their binding to various mammalian cells [Simonova, O.N.,Vladimirova, A.V., Zenkova, M.A., and Vlassov, V.V. (2006). Biochim. Biophys. Acta 1758, 413-418]. We attempted to improve the efficiency of oligonucleotide concatemer delivery into cells by the attachment of lipophilic cholesterol molecules to the components of concatemeric complexes. Uptake, cellular distribution, and biological activity of the supramolecular complexes formed by delivered antisense oligonucleotides and cholesterol-modified "carrier" oligonucleotides were studied. Our results demonstrate that incorporation of an antisense oligonucleotide into the self-assembling concatemeric system promotes its delivery into cells without the addition of any supplementary transfection agents and allows achieving specific inhibition of the target gene expression.

DNA-based therapeutics and DNA delivery systems: a comprehensive review

The past several years have witnessed the evolution of gene medicine from an experimental technology into a viable strategy for developing therapeutics for a wide range of human disorders. Numerous prototype DNA-based biopharmaceuticals can now control disease progression by induction and/or inhibition of genes. These potent therapeutics include plasmids containing transgenes, oligonucleotides, aptamers, ribozymes, DNAzymes, and small interfering RNAs. Although only 2 DNA-based pharmaceuticals (an antisense oligonucleotide formulation, Vitravene, (USA, 1998), and an adenoviral gene therapy treatment, Gendicine (China, 2003), have received approval from regulatory agencies; numerous candidates are in advanced stages of human clinical trials. Selection of drugs on the basis of DNA sequence and structure has a reduced potential for toxicity, should result in fewer side effects, and therefore should eventually yield safer drugs than those currently available. These predictions are based on the high selectivity and specificity of such molecules for recognition of their molecular targets. However, poor cellular uptake and rapid in vivo degradation of DNA-based therapeutics necessitate the use of delivery systems to facilitate cellular internalization and preserve their activity. This review discusses the basis of structural design, mode of action, and applications of DNA-based therapeutics. The mechanisms of cellular uptake and intracellular trafficking of DNA-based therapeutics are examined, and the constraints these transport processes impose on the choice of delivery systems are summarized. Finally, the development of some of the most promising currently available DNA delivery platforms is discussed, and the merits and drawbacks of each approach are evaluated.