Review
Gene therapy and DNA delivery systems

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Abstract

Gene therapy is a promising new technique for treating many serious incurable diseases, such as cancer and genetic disorders. The main problem limiting the application of this strategy in vivo is the difficulty of transporting large, fragile and negatively charged molecules like DNA into the nucleus of the cell without degradation. The key to success of gene therapy is to create safe and efficient gene delivery vehicles. Ideally, the vehicle must be able to remain in the bloodstream for a long time and avoid uptake by the mononuclear phagocyte system, in order to ensure its arrival at the desired targets. Moreover, this carrier must also be able to transport the DNA efficiently into the cell cytoplasm, avoiding lysosomal degradation. Viral vehicles are the most commonly used carriers for delivering DNA and have long been used for their high efficiency. However, these vehicles can trigger dangerous immunological responses. Scientists need to find safer and cheaper alternatives. Consequently, the non-viral carriers are being prepared and developed until techniques for encapsulating DNA can be found. This review highlights gene therapy as a new promising technique used to treat many incurable diseases and the different strategies used to transfer DNA, taking into account that introducing DNA into the cell nucleus without degradation is essential for the success of this therapeutic technique.

Introduction

Gene therapy is a promising therapeutic strategy (Friedmann, 1996) based on using genes as a medicine (Mohsen, 2011). It can be employed effectively to cure a wide range of serious acquired and inherited diseases (Gardlík et al., 2005), such as cancer (Rochlitz, 2001), acquired immunodeficiency syndrome (AIDS) (Yu et al., 1994), cardiovascular diseases (Dishart et al., 2003), infectious diseases (Bunnell and Morgan, 1998), cystic fibrosis (Davies et al., 2001), and X-linked severe combined immune deficiency (X-linked SCID) (Kohn et al., 2003). Theoretically, gene therapy is a simple therapeutic method depending on either replacing a distorted gene by healthy one, or completing a missing gene in order to express the required protein (Zhang et al., 2004b). However, in practice this is a complex operation (Tong et al., 2007), due to several obstacles that must be overcome by the transgene to reach the targeted human cell-nucleus, where it should be expressed correctly. Hence, for ensuring the arrival of a transgene into a cell nucleus without degradation, it is necessary to use gene delivery system that can protect the transgene from degradation and pass through the plasma membrane to the nucleus (Luo and Saltzman, 2000, Gao et al., 2007). At present, a perfect delivering system (carrier) capable of ensuring the success of gene therapy must satisfy the following criteria: (i) it must not interact with vascular endothelial cells and blood components (Schatzlein, 2001); (ii) it must be capable of avoiding uptake by the reticuloendothelial system (Mohsen, 2011); (iii) it must be small enough to pass through the cell-membrane and reach the nucleus (Labhasetwar, 2005). In fact, viruses were the first carriers to be used to deliver and protect the therapeutic gene, benefiting from the virus-life cycle. This type of carrier, known as viral vector, is one of the vectors used most in gene therapy, due to its ability to carry the gene efficiently and ensure long-term expression (Boulaiz et al., 2005). However, the risk of provoking immune response by using viruses as delivering vectors (Lv et al., 2006, El-Aneed, 2004), the high cost and difficulty relating to their preparation (Boulaiz et al., 2005), and the limited size of the genetic materials that can be inserted into human cells (Lv et al., 2006, El-Aneed, 2004), have restricted the use of these vectors in gene therapy, and led to research into safer and cheaper alternatives. Therefore non-viral vectors have appeared. Non-viral approaches for delivering transgenes can be divided into two groups:

  • 1-

    Physical approaches: these depend on a physical force that weakens the cell membrane to facilitate the penetration of the gene into the nucleus. They include needle injection, electroporation, gene gun, ultrasound, and hydrodynamic delivery.

  • 2-

    Chemical vectors: these can be prepared by electrostatic interaction between poly cationic derivatives that can be lipids or polymers and the anionic phosphate of DNA to form a particle called polyplexe when the interaction occurs between the polymer and the DNA, and lipoplexe when the DNA interacts with a lipid, or by encapsulation of DNA within biodegradable spherical structures that lead to micro and nanoparticles containing DNA, or by adsorption of DNA.

Section snippets

Protein therapy and gene therapy

Proteins have been used for treating various kinds of diseases for a long time (Goddard, 1991, Talmadge, 1993) in what is known as protein therapy, but using proteins for treating diseases is confronted by many obstacles such as low bioavailability in the body, short life in the blood stream due to high rates of hepatic and renal clearance and in vivo instability as it can degrade in the biological medium. The latter two constraints make it necessary to repeat recombinant protein-injection

The harbingers of gene therapy

Since 1944, the year in which Avery, Mcleod and Mc Carthy, proved that DNA encodes human genetic information (Avery et al., 1944, Dahm, 2010), much valuable genetic information was published until, finally, Watson and Crick published their article on the double helix structure of DNA in 1953 (Watson and Crick, 1953). This led to a genuine genetic revolution that led to understanding the mechanisms of many diseases, and to the development of new treatment methods, such as gene therapy. The major

Classification of gene therapy

The main goal of gene therapy is to insert a functional gene that plays the role of drug into the cell targeted in order to cure a disease or to repair a dysfunction caused by a genetic defect. Gene therapy can be classified into two major categories according to the nature of targeted cell.

Clinical gene therapy trials

The expression gene therapy owes its origin to the term “genetic engineering” which was employed for the first time at the Sixth International Congress of Genetics held at Ithaca in 1932 (Wolff and Lederberg, 1994). Though the idea of gene therapy existed already, concrete development in this field began in late 1960s and early 1970s (Friedmann, 1992) (Roemer and Friedmann, 1992) and gene therapy in humans was practiced in the late 1980s (Anderson, 1992) as a result of developments in the field

Gene therapy: principle and vectors

Gene therapy is a technique employed recently to treat serious diseases (acquired or inherited) by correcting their genetic causes (Müller-Reible, 1994), either by replacing the deformed genes by healthy ones or by completing missing genes (Sandhu et al., 1997). Different types of genetic material are used in gene therapy; such as double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), plasmid DNA (Ferreira et al., 2000) and anti-sense oligonucleotides (ASON) (Knipe et al., 2013). The success

Conclusion

The main purpose of all of these pharmaceutical developments is to increase the desired medical impacts of a drug, and to decrease the side effects related to its use. This is the main objective now in gene therapy, in which when DNA is the drug to be administered. Gene therapy has become a promising strategy for treating many incurable diseases, whether acquired or heritable. However, the main challenge facing gene therapy, which prevents its widespread use in vivo is to find efficient

Acknowledgments

The authors thank and appreciate the research grant from Syrian government. The authors also thank MILADI Karim for his technical help and discussions.

References (195)

  • R. Heller et al.

    In vivo gene electroinjection and expression in rat liver

    Febs Lett.

    (1996)
  • S.-L. Huang

    Liposomes in ultrasonic drug and gene delivery

    Adv. Drug Deliv. Rev.

    (2008)
  • P.E. Huber et al.

    A comparison of shock wave and sinusoidal-focused ultrasound-induced localized transfection of HeLa cells

    Ultrasound Med. Biol.

    (1999)
  • S.P. Kasturi et al.

    Covalent conjugation of polyethyleneimine on biodegradable microparticles for delivery of plasmid DNA vaccines

    Biomaterials

    (2005)
  • K. Kataoka et al.

    Block copolymer micelles for drug delivery: design, characterization and biological significance

    Adv. Drug Deliv. Rev.

    (2001)
  • S. Katayose et al.

    Remarkable increase in nuclease resistance of plasmid DNA through supramolecular assembly with poly(ethylene glycol)—poly(L-lysine) block copolymer

    J. Pharm. Sci.

    (1998)
  • K. Kazunori et al.

    Block copolymer micelles as vehicles for drug delivery

    J. Control. Release

    (1993)
  • M. Kendirci et al.

    Gene therapy for erectile dysfunction: fact or fiction?

    Eur. Urol.

    (2006)
  • D.-W. Kim et al.

    Multicenter phase II trial of Genexol-PM, a novel Cremophor-free, polymeric micelle formulation of paclitaxel, with cisplatin in patients with advanced non-small-cell lung cancer

    Ann. Oncol.

    (2007)
  • R. Kircheis et al.

    Design and gene delivery activity of modified polyethylenimines

    Adv. Drug Deliv. Rev.

    (2001)
  • J.M. Knipe et al.

    Theranostic agents for intracellular gene delivery with spatiotemporal imaging

    Nano Today

    (2013)
  • F. Krötz et al.

    Magnetofection—a highly efficient tool for antisense oligonucleotide delivery in vitro and in vivo

    Mol. Ther. J. Am. Soc. Gene Ther.

    (2003)
  • C.G. De Kruif et al.

    Complex coacervation of proteins and anionic polysaccharides

    Curr. Opin. Colloid Interface Sci.

    (2004)
  • V. Labhasetwar

    Nanotechnology for drug and gene therapy: the importance of understanding molecular mechanisms of delivery

    Curr. Opin. Biotechnol.

    (2005)
  • F.D. Ledley et al.

    Pharmacokinetic considerations in somatic gene therapy

    Adv. Drug Deliv. Rev.

    (1998)
  • K. Leong et al.

    DNA-polycation nanospheres as non-viral gene delivery vehicles

    J. Control. Release

    (1998)
  • D.C. Litzinger et al.

    Fate of cationic liposomes and their complex with oligonucleotive in vivo

    Biochim. Biophys. Acta Bba—Biomembr.

    (1996)
  • Y. Lu et al.

    Polymeric micelles and alternative nanonized delivery vehicles for poorly soluble drugs

    Int. J. Pharm.

    (2013)
  • H. Lv et al.

    Toxicity of cationic lipids and cationic polymers in gene delivery

    J. Control. Release

    (2006)
  • A. Ahsan et al.

    Smart magnetically engineering colloids and biothin films for diagnostics applications

    J. Colloid Sci. Biotechnol.

    (2013)
  • H. Aihara et al.

    Gene transfer into muscle by electroporation in vivo

    Nat. Biotechnol.

    (1998)
  • T. Ajiki et al.

    Long-lasting gene expression by particle-mediated intramuscular transfection modified with bupivacaine: combinatorial gene therapy with IL-12 and IL-18 cDNA against rat sarcoma at a distant site

    Cancer Gene Ther.

    (2003)
  • W.F. Anderson

    Human gene therapy

    Science

    (1992)
  • O.T. Avery et al.

    Studies on the chemical nature of the substance inducing transformation of pneumococcal types induction of transformation by a desoxyribonucleic acid fraction isolated from pneumococcus type III

    J. Exp. Med.

    (1944)
  • M.S. Al-Dosari et al.

    Nonviral gene delivery: principle, limitations, and recent progress

    Aaps J.

    (2009)
  • O. Bagasra et al.

    Liposomes in gene therapy

  • D.A. Balazs et al.

    Liposomes for use in gene delivery

    J. Drug Deliv.

    (2010)
  • A.D. Bangham et al.

    Negative staining of phospholipids and their structural modification by surface-active agents as observed in the electron microscope

    J. Mol. Biol.

    (1964)
  • R. Bekeredjian et al.

    Ultrasound-targeted microbubble destruction can repeatedly direct highly specific plasmid expression to the heart

    Circulation

    (2003)
  • J.M. Bergen et al.

    Nonviral approaches for neuronal delivery of nucleic acids

    Pharm. Res.

    (2008)
  • D. Bouard et al.

    Viral vectors: from virology to transgene expression

    Br. J. Pharmacol.

    (2009)
  • H. Boulaiz et al.

    Non-viral and viral vectors for gene therapy

    Cell. Mol. Biol. Noisy—Gd. Fr

    (2005)
  • O. Boussif et al.

    A versatile vector for gene and oligonucleotide transfer into cells in culture and in vivo: polyethylenimine

    Proc. Natl. Acad. Sci.

    (1995)
  • V. Budker et al.

    The efficient expression of intravascularly delivered DNA in rat muscle

    Gene Ther.

    (1998)
  • B.A. Bunnell et al.

    Gene therapy for infectious diseases

    Clin. Microbiol. Rev.

    (1998)
  • A. Cahouet et al.

    Biodistribution of dual radiolabeled lipidic nanocapsules in the rat using scintigraphy and γ counting

    Int. J. Pharm.

    (2013)
  • E.V.R. Campos et al.

    Screening of conditions for the preparation of poly(-caprolactone) nanocapsules containing the local anesthetic articaine

    J. Colloid Sci. Biotechnol.

    (2013)
  • I. Chemin et al.

    Liver-directed gene transfer: a linear polyethylenimine derivative mediates highly efficient DNA delivery to primary hepatocytes in vitro and in vivo

    J. Viral Hepat.

    (1998)
  • Y.S. Cho-Chung

    DNA drug design for cancer therapy

    Curr. Pharm. Des.

    (2005)
  • H. Cohen et al.

    Sustained delivery and expression of DNA encapsulated in polymeric nanoparticles

    Gene Ther.

    (2000)
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