Subscriber access provided by Olson Library | Northern Michigan University
Review
Challenges in DNA Delivery and Recent Advances in Multifunctional Polymeric DNA Delivery System Bingyang Shi, Meng Zheng, Wei Tao, Roger Chung, Dayong Jin, Dariush Ghaffari, and Omid C Farokhzad Biomacromolecules, Just Accepted Manuscript • DOI: 10.1021/acs.biomac.7b00803 • Publication Date (Web): 29 Jun 2017 Downloaded from http://pubs.acs.org on July 1, 2017
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Biomacromolecules is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 52
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Biomacromolecules
Challenges in DNA Delivery and Recent Advances in Multifunctional Polymeric DNA Delivery System
Bingyang Shi,*, † Meng Zheng,† Wei Tao,# Roger Chung,‡ Dayong Jin,§, ǁ Dariush Ghaffari,# and Omid C. Farokhzad*, #
†
International Joint Center for Biomedical Innovation, School of Life Sciences, Henan University,
Kaifeng, Henan, 475004, P. R. China ‡
Faculty of Medicine and Health Science, Macquarie University, Sydney, New South Wales, 2109,
Australia §
ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University, Sydney, New
South Wales, 2109, Australia ǁ
Institute for Biomedical Materials and Devices (IBMD), University of Technology Sydney, New South
Wales, 2007, Australia #
Center for Nanomedicine and Department of Anesthesiology, Brigham and Women’s Hospital, Harvard
Medical School, Boston, MA 02115
* Corresponding Authors: B.S. (Email:
[email protected]), and O.C.F. (Email:
[email protected])
ACS Paragon Plus Environment
Biomacromolecules
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ABSTRACT After more than 20 years of intensive investigations, gene therapy has become one of the most promising strategies for treating genetic diseases. However, the lack of ideal delivery systems has limited the clinical realization of gene therapy’s tremendous potential, especially for DNA-based gene therapy. Over the past decade, considerable advances have been made in the application of polymer-based DNA delivery systems for gene therapy, especially through multifunctional systems. The core concept behind multifunctional polymeric DNA delivery systems is to endow one single DNA carrier, via materials engineering and surface modification, with several active functions, e.g., good cargo DNA protection, excellent colloidal stability, high cellular uptake efficiency, efficient endo-/lysosome escape, effective import into the nucleus, and DNA unpacking. Such specially developed vectors would be capable of overcoming multiple barriers to the successful delivery of DNA. In this review, we first provide a comprehensive overview of the interactions between the protein corona and DNA vectors, the mechanisms and challenges of non-viral DNA vectors, and important concepts in the design of DNA carriers identified via past reports on DNA delivery systems. Finally, we highlight and discuss recent advances in multifunctional polymeric DNA delivery systems, based on “off-the-shelf” polycations including polyethylenimine (PEI), poly-L-lysine (PLL), and chitosan, and offer perspectives on future developments.
ACS Paragon Plus Environment
Page 2 of 52
Page 3 of 52
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Biomacromolecules
1. INTRODUCTION Gene therapy is the transport of therapeutic genes into the chromosomes of targeted tissues or cells to regulate or replace abnormal genes. After 20 years of intensive research, gene therapy is now among the most promising approaches for the treatment of genetic diseases, such as mitochondrial-related diseases,1 blindness,2 muscular dystrophy,3 cystic fibrosis,4 and certain cancers.5-6 With the completion of the Human Genome Project, recent progress in elucidating the molecular basis of genetic diseases has accelerated the technology around the development of gene therapy. Since the first successful trial of a treatment for severe combined immunodeficiencies (SCIDs) in the 1990s,7-8 there have been more than 2,409 approved clinical trials of gene therapies.9 These have sought to treat a variety of diseases (Figure 1A) such as cancer-related diseases (64.5%), monogenic diseases (10.3%), infectious diseases (7.5%), and cardiovascular diseases (7.4%).9 And most of approved clinical trials (94.9%) are viral carriers which are still in phase І, I/II, or II (proof-of-concept). Only three clinical trials (0.1%) have reached phase IV (efficacy) (Figure 1B).9 The complexity of targeted gene delivery, which entails traversing a number of biological barriers, requires that both scientific and technical issues be resolved before the full potential of gene therapy is realized.10 For example, the repair of genetic defects through the injection of naked plasmid DNA has not been effective due to poor transfection efficiency. Though viral vectors with sufficiently high efficiency for DNA delivery are available, they can evoke undesirable immune responses. In overcoming these challenges, approaches involving non-viral DNA delivery show great promise11-13 and have been widely investigated for the last 15 years. An extensive set of nanoscale DNA carriers has now been developed: polymeric,14 silica-based hybrids,15 gold nanoparticle-based hybrids,16 two-dimensional nanomaterialsbased,17-18 and lipid-based.19 However, only several kinds of non-viral carriers under clinical trials including DOTAP-cholesterol, polyethylenimine (PEI), poly (ethylene glycol)-polyethyleniminecholesterol (PEG-PEI-cholesterol) and PEI-mannose-dextrose etc.20
ACS Paragon Plus Environment
Biomacromolecules
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Polymer-based carriers offer several advantages: they can form nanoscale polyplexes (50 – 150 nm) with nucleic acids, and their surface properties allow various targeting biomacromolecules such as antibodies (4 – 10 nm) to recognize a variety of biological targets of different sizes, e.g., bacteria 0.15 – 2 µm, normal cells 10 – 30 µm, neuronal cells 4 – 100 µm, and other tissues (whose sizes are depicted in Figure 2). Their chemical and physical properties facilitate the transport of therapeutic nucleic acids to penetrate the cell membrane, rupture the endosome (200 – 500 nm), and enter the nucleus (5 – 10 µm) for DNA expression (Figure 2). Compared to viral vectors (whose sizes are 10 – 100 nm), synthetic polymers are relatively cheap, safe, amenable to high production capacity, and highly duplicable according to TGA (Therapeutic Goods Administration) standards. However, the relatively low transfection efficiency and high cytotoxicity of currently available polymer-based synthetic DNA carriers do not satisfy the requirements of gene therapy for clinical applications. Therefore, intensive efforts have been focused on design and validation of new functional synthetic DNA carriers with better transfection efficiency and biocompatibility. Before discussing the construction of effective DNA carriers, we will first elucidate the mechanisms and challenges involved in DNA delivery. 2. UNDERSTANDING THE MECHANISMS AND CHALLENGES OF DNA DELIVERY DNA delivery is a multi-step process that begins with the condensation of DNA, the introduction of DNA into the systemic circulation, and targeted delivery to specific cells, followed by cellular uptake, endosomal release, nuclear transport, and unpacking the carrier/DNA polyplexes, before the final step of translation in eukaryotic cells (Figure 3). Each of these steps presents specific challenges to the design of carrier-aided DNA delivery, whose physical, chemical, and biological properties must accommodate all these extracellular and intracellular steps (Table 1). Therefore, the key mechanisms and challenges of each of these steps need to be thoroughly considered in the design of more therapeutically active DNA delivery systems with limited side effects. Before talking about these vital mechanisms for polymeric DNA vectors, we also provide a brief overview of virus-based DNA delivery vectors and their limitations. Very recent outstanding work is highlighted to provide some insight into the prevention of immune
ACS Paragon Plus Environment
Page 4 of 52
Page 5 of 52
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Biomacromolecules
responses. Finally, to further improve the design of polymeric DNA vectors, we also discuss the state of our emerging understanding of the protein corona’s influence on delivery vectors. 2.1. Condensation of DNA Cargo. To protect it from digestion by nuclease and aid its cellular uptake, negatively charged DNA needs to be loaded into a DNA carrier and condensed into a compact nanoparticle (polyplex)
