51
|
Segal E, Satchi-Fainaro R. Design and development of polymer conjugates as anti-angiogenic agents. Adv Drug Deliv Rev 2009; 61:1159-76. [PMID: 19699248 DOI: 10.1016/j.addr.2009.06.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 06/12/2009] [Indexed: 12/17/2022]
Abstract
Angiogenesis, the formation of new blood vessels from pre-existing vasculature, is one of the central key steps in tumor progression and metastasis. Consequently, it became an important target in cancer therapy, making novel angiogenesis inhibitors a new modality of anticancer agents. Although relative to conventional chemotherapy, anti-angiogenic agents display a safer toxicity profile, the vast majority of these agents are low-molecular-weight compounds exhibiting poor pharmacokinetic profile with short half-life in the bloodstream and high overall clearance rate. The "Polymer Therapeutics" field has significantly improved the therapeutic potential of low-molecular-weight drugs and proteins for cancer treatment. Drugs can be conjugated to polymeric carriers that can be either directly conjugated to targeting proteins or peptides or derivatized with adapters conjugated to a targeting moiety. This approach holds a significant promise for the development of new targeted anti-angiogenic therapies as well as for the optimization of existing anti-angiogenic drugs or polypeptides. Here we overview the innovative approach of targeting tumor angiogenesis using polymer therapeutics.
Collapse
|
52
|
Wu FTH, Stefanini MO, Mac Gabhann F, Kontos CD, Annex BH, Popel AS. A systems biology perspective on sVEGFR1: its biological function, pathogenic role and therapeutic use. J Cell Mol Med 2009; 14:528-52. [PMID: 19840194 PMCID: PMC3039304 DOI: 10.1111/j.1582-4934.2009.00941.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Angiogenesis is the growth of new capillaries from pre-existent microvasculature. A wide range of pathological conditions, from atherosclerosis to cancer, can be attributed to either excessive or deficient angiogenesis. Central to the physiological regulation of angiogenesis is the vascular endothelial growth factor (VEGF) system – its ligands and receptors (VEGFRs) are thus prime molecular targets of pro-angiogenic and anti-angiogenic therapies. Of growing interest as a prognostic marker and therapeutic target in angiogenesis-dependent diseases is soluble VEGF receptor-1 (sVEGFR1, also known as sFlt-1) – a truncated version of the cell membrane-spanning VEGFR1. For instance, it is known that sVEGFR1 is involved in the endothelial dysfunction characterizing the pregnancy disorder of pre-eclampsia, and sVEGFR1’s therapeutic potential as an anti-angiogenic agent is being evaluated in pre-clinical models of cancer. This mini review begins with an examination of the protein domain structure and biomolecular interactions of sVEGFR1 in relation to the full-length VEGFR1. A synopsis of known and inferred physiological and pathological roles of sVEGFR1 is then given, with emphasis on the utility of computational systems biology models in deciphering the molecular mechanisms by which sVEGFR1’s purported biological functions occur. Finally, we present the need for a systems biology perspective in interpreting circulating VEGF and sVEGFR1 concentrations as surrogate markers of angiogenic status in angiogenesis-dependent diseases.
Collapse
Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | | | | | |
Collapse
|
53
|
Oba M, Aoyagi K, Miyata K, Matsumoto Y, Itaka K, Nishiyama N, Yamasaki Y, Koyama H, Kataoka K. Polyplex micelles with cyclic RGD peptide ligands and disulfide cross-links directing to the enhanced transfection via controlled intracellular trafficking. Mol Pharm 2009; 5:1080-92. [PMID: 19434856 DOI: 10.1021/mp800070s] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Thiolated c(RGDfK)-poly(ethylene glycol)-block-poly(lysine) (PEG-PLys), a novel block polymer that has a cyclic RGD peptide in the PEG terminus and thiol groups in the PLys side chain, was prepared and applied to the preparation of targetable disulfide cross-linked polyplex micelles through ion complexation with plasmid DNA (pDNA). The obtained polyplex micelles achieved remarkably enhanced transfection efficiency against cultured HeLa cells possessing alpha(v)beta(3) integrin receptors, which are selectively recognized by cyclic RGD peptides, demonstrating the synergistic effect of cyclic RGD peptide ligands on the micelle surface and disulfide cross-links in the core to exert the smooth release of pDNA in the intracellular environment via reductive cleavage. This enhancement was not due to an increase in the uptake amount of polyplex micelles but to a change in their intracellular trafficking route. Detailed confocal laser scanning microscopic observation revealed that polyplex micelles with cyclic RGD peptide ligands were distributed in the perinuclear region in the early stages preferentially through caveolae-mediated endocytosis, which may be a desirable pathway for avoiding the lysosomal degradation of delivered genes. Hence, this approach to introducing ligands and cross-links into the polyplex micelles is promising for the construction of nonviral gene vectors that enhance transfection by controlling intracellular distribution.
Collapse
Affiliation(s)
- Makoto Oba
- Department of Clinical Vascular Regeneration, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8655, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
54
|
Merkel OM, Germershaus O, Wada CK, Tarcha PJ, Merdan T, Kissel T. Integrin ανβ3 Targeted Gene Delivery Using RGD Peptidomimetic Conjugates with Copolymers of PEGylated Poly(ethylene imine). Bioconjug Chem 2009; 20:1270-80. [DOI: 10.1021/bc9001695] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Olivia M. Merkel
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| | - Oliver Germershaus
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| | - Carol K. Wada
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| | - Peter J. Tarcha
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| | - Thomas Merdan
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| | - Thomas Kissel
- Department of Pharmaceutics and Biopharmacy, Philipps-Universität Marburg, Ketzerbach 63, 35032 Marburg, Germany, and Abbott Laboratories Incorporated, 200 Abbott Park Road, Abbot Park, Illinois 60064
| |
Collapse
|
55
|
64Cu-Labeled PEGylated Polyethylenimine for Cell Trafficking and Tumor Imaging. Mol Imaging Biol 2009; 11:415-23. [DOI: 10.1007/s11307-009-0228-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/09/2009] [Accepted: 02/03/2009] [Indexed: 11/25/2022]
|
56
|
Wu FTH, Stefanini MO, Mac Gabhann F, Popel AS. A compartment model of VEGF distribution in humans in the presence of soluble VEGF receptor-1 acting as a ligand trap. PLoS One 2009; 4:e5108. [PMID: 19352513 PMCID: PMC2663039 DOI: 10.1371/journal.pone.0005108] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 03/10/2009] [Indexed: 12/25/2022] Open
Abstract
Vascular endothelial growth factor (VEGF), through its activation of cell surface receptor tyrosine kinases including VEGFR1 and VEGFR2, is a vital regulator of stimulatory and inhibitory processes that keep angiogenesis--new capillary growth from existing microvasculature--at a dynamic balance in normal physiology. Soluble VEGF receptor-1 (sVEGFR1)--a naturally-occurring truncated version of VEGFR1 lacking the transmembrane and intracellular signaling domains--has been postulated to exert inhibitory effects on angiogenic signaling via two mechanisms: direct sequestration of angiogenic ligands such as VEGF; or dominant-negative heterodimerization with surface VEGFRs. In pre-clinical studies, sVEGFR1 gene and protein therapy have demonstrated efficacy in inhibiting tumor angiogenesis; while in clinical studies, sVEGFR1 has shown utility as a diagnostic or prognostic marker in a widening array of angiogenesis-dependent diseases. Here we developed a novel computational multi-tissue model for recapitulating the dynamic systemic distributions of VEGF and sVEGFR1. Model features included: physiologically-based multi-scale compartmentalization of the human body; inter-compartmental macromolecular biotransport processes (vascular permeability, lymphatic drainage); and molecularly-detailed binding interactions between the ligand isoforms VEGF(121) and VEGF(165), signaling receptors VEGFR1 and VEGFR2, non-signaling co-receptor neuropilin-1 (NRP1), as well as sVEGFR1. The model was parameterized to represent a healthy human subject, whereupon we investigated the effects of sVEGFR1 on the distribution and activation of VEGF ligands and receptors. We assessed the healthy baseline stability of circulating VEGF and sVEGFR1 levels in plasma, as well as their reliability in indicating tissue-level angiogenic signaling potential. Unexpectedly, simulated results showed that sVEGFR1 - acting as a diffusible VEGF sink alone, i.e., without sVEGFR1-VEGFR heterodimerization--did not significantly lower interstitial VEGF, nor inhibit signaling potential in tissues. Additionally, the sensitivity of plasma VEGF and sVEGFR1 to physiological fluctuations in transport rates may partially account for the heterogeneity in clinical measurements of these circulating angiogenic markers, potentially hindering their diagnostic reliability for diseases.
Collapse
Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
| | | | | | | |
Collapse
|
57
|
Osada K, Christie RJ, Kataoka K. Polymeric micelles from poly(ethylene glycol)-poly(amino acid) block copolymer for drug and gene delivery. J R Soc Interface 2009; 6 Suppl 3:S325-39. [PMID: 19364722 PMCID: PMC2690088 DOI: 10.1098/rsif.2008.0547.focus] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Dramatic advances in biological research have revealed the mechanisms underlying many diseases at the molecular level. However, conventional techniques may be inadequate for direct application of this new knowledge to medical treatments. Nanobiotechnology, which integrates biology with the rapidly growing field of nanotechnology, has great potential to overcome many technical problems and lead to the development of effective therapies. The use of nanobiotechnology in drug delivery systems (DDS) is attractive for advanced treatment of conditions such as cancer and genetic diseases. In this review paper for a special issue on biomaterial research in Japan, we discuss the development of DDS based on polymeric micelles mainly in our group for anti-cancer drug and gene delivery, and also address our challenges associated with developing polymeric micelles as super-functionalized nanodevices with intelligent performance.
Collapse
Affiliation(s)
- Kensuke Osada
- Department of Materials Engineering, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | | | | |
Collapse
|
58
|
Di Gioia S, Conese M. Polyethylenimine-mediated gene delivery to the lung and therapeutic applications. DRUG DESIGN DEVELOPMENT AND THERAPY 2009; 2:163-88. [PMID: 19920904 PMCID: PMC2761186 DOI: 10.2147/dddt.s2708] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nonviral gene delivery is now considered a promising alternative to viral vectors. Among nonviral gene delivery agents, polyethylenimine (PEI) has emerged as a potent candidate for gene delivery to the lung. PEI has some advantages over other polycations in that it combines strong DNA compaction capacity with an intrinsic endosomolytic activity. However, intracellular (mainly the nuclear membrane) and extracellular obstacles still hamper its efficiency in vitro and in vivo, depending on the route of administration and the type of PEI. Nuclear delivery has been increased by adding nuclear localization signals. To overcome nonspecific interactions with biological fluids, extracellular matrix components and nontarget cells, strategies have been developed to protect polyplexes from these interactions and to increase target specificity and gene expression. When gene delivery into airway epithelial cells of the conducting airways is necessary, aerosolization of complexes seems to be better suited to guarantee higher transgene expression in the airway epithelial cells with lower toxicity than observed with either intratracheal or intravenous administration. Aerosolization, indeed, is useful to target the alveolar epithelium and pulmonary endothelium. Proof-of-principle that PEI-mediated gene delivery has therapeutic application to some genetic and acquired lung disease is presented, using as genetic material either plasmidic DNA or small-interfering RNA, although optimization of formulation and delivery protocols and limitation of toxicity need further studies.
Collapse
Affiliation(s)
- Sante Di Gioia
- Department of Biomedical Sciences, University of Foggia, Viale L. Pinto 1, Foggia, Italy
| | | |
Collapse
|
59
|
Paleos CM, Tziveleka LA, Sideratou Z, Tsiourvas D. Gene delivery using functional dendritic polymers. Expert Opin Drug Deliv 2009; 6:27-38. [DOI: 10.1517/17425240802607345] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
60
|
Efficient siRNA delivery with non-viral polymeric vehicles. Pharm Res 2008; 26:657-66. [PMID: 19015957 DOI: 10.1007/s11095-008-9774-1] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Accepted: 10/28/2008] [Indexed: 10/21/2022]
Abstract
Sequence-specific gene silencing using small interfering RNA (siRNA) provides a potent and specific method for gene expression, thus is now being evaluated in clinical trials as a novel therapeutic strategy. As a results, there has been a significant surge of interest in the application of siRNA in therapeutics as a means of silencing the specific gene function. However, for siRNA technology to be valuable and effective, the development of efficient siRNA delivery strategy is essential for improving biological activities such as stability, cellular uptake, sequence-specificity, devoid of nonspecific knockdown and toxic side effects. Accordingly, a number of delivery systems, both viral and nonviral, have been reported and some of them successfully used for the introduction of siRNA into cells both in vitro and in vivo. Here, we discuss the current understanding of synthetic siRNA delivery mechanism and strategies of siRNA delivery by non-viral polymeric vehicles which are currently used in vitro and in vivo.
Collapse
|
61
|
Park K, Kim YS, Lee GY, Park RW, Kim IS, Kim SY, Byun Y. Tumor Endothelial Cell Targeted Cyclic RGD-modified Heparin Derivative: Inhibition of Angiogenesis and Tumor Growth. Pharm Res 2008; 25:2786-98. [DOI: 10.1007/s11095-008-9643-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 05/29/2008] [Indexed: 11/30/2022]
|
62
|
Linear poly(ethylenimine)-graft-poly(ethylene glycol) copolymers: Their micellization and secondary assembly. J Colloid Interface Sci 2008; 320:62-9. [DOI: 10.1016/j.jcis.2007.11.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 11/24/2007] [Accepted: 11/27/2007] [Indexed: 11/17/2022]
|
63
|
Huang M, Huang ZL, Bilgen M, Berkland C. Magnetic resonance imaging of contrast-enhanced polyelectrolyte complexes. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2008; 4:30-40. [DOI: 10.1016/j.nano.2007.10.085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 10/04/2007] [Accepted: 10/08/2007] [Indexed: 11/28/2022]
|
64
|
|
65
|
Huang D, Korolev N, Eom KD, Tam JP, Nordenskiöld L. Design and Biophysical Characterization of Novel Polycationic ϵ-Peptides for DNA Compaction and Delivery. Biomacromolecules 2007; 9:321-30. [DOI: 10.1021/bm700882g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Dandan Huang
- School of Biological Sciences, Nanyang Technological University, 60, Nanyang Drive, Singapore 637551, and Biochemistry, The Scripps Research Institute, Parkside Drive, Jupiter, Florida 33458
| | - Nikolay Korolev
- School of Biological Sciences, Nanyang Technological University, 60, Nanyang Drive, Singapore 637551, and Biochemistry, The Scripps Research Institute, Parkside Drive, Jupiter, Florida 33458
| | - Khee Dong Eom
- School of Biological Sciences, Nanyang Technological University, 60, Nanyang Drive, Singapore 637551, and Biochemistry, The Scripps Research Institute, Parkside Drive, Jupiter, Florida 33458
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological University, 60, Nanyang Drive, Singapore 637551, and Biochemistry, The Scripps Research Institute, Parkside Drive, Jupiter, Florida 33458
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, 60, Nanyang Drive, Singapore 637551, and Biochemistry, The Scripps Research Institute, Parkside Drive, Jupiter, Florida 33458
| |
Collapse
|
66
|
Yockman JW, Kim WJ, Chang CW, Kim SW. Non-viral delivery of interleukin-2 and soluble Flk-1 inhibits metastatic and primary tumor growth in renal cell carcinoma. Gene Ther 2007; 14:1399-405. [PMID: 17653245 DOI: 10.1038/sj.gt.3302999] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Treatments for renal cell carcinoma, while promising, are still limited by toxicity and cost. In the hopes of finding a novel compound or combination, we developed a plasmid containing the genes for interleukin-2 (IL-2) and soluble vascular endothelial growth factor receptor 2 (msFlk1). The plasmid, p2CMVIL2/msFlk1, demonstrated similar in vitro transgene expression of IL-2 or msFlk1 compared to their single-agent counterparts. Subcutaneous tumor growth was significantly inhibited in the p2CMVIL2/msFlk1 group when delivered locally by the non-viral water soluble polymer, WSLP and exhibited a 50% increase in survival over glucose and single-agent controls. In vivo experimentation demonstrated that WSLP/msFlk1 decreased microvessel density in pCMVmsFlk1 and p2CMVIL2/msFlk1 treated groups. Furthermore, tumor-infiltrating lymphocytes expressing CD45RO and CD68 were increased within the tumor microenvironment upon p2CMVIL2/msFlk1 treatment. To determine the effects of p2CMVIL2/msFlk1 in an experimental RENCA lung metastases model, therapeutic DNA was delivered systemically following complexation with the angiogenic endothelial-targeting polymer PEI-g-PEG-RGD. The p2CMVIL2/msFlk1 treatment significantly reduced metastases by 56% over single-agent therapy and increased survival proportions by 50% over all groups. Our work clearly demonstrates that non-viral delivery of p2CMVIL2/msFlk1 can inhibit RENCA growth in a synergistic manner and may represent a new treatment for renal carcinoma.
Collapse
MESH Headings
- Animals
- Antigens, CD/immunology
- Antigens, Differentiation, Myelomonocytic/immunology
- Carcinoma, Renal Cell/immunology
- Carcinoma, Renal Cell/metabolism
- Carcinoma, Renal Cell/secondary
- Carcinoma, Renal Cell/therapy
- Combined Modality Therapy
- Drug Carriers
- Female
- Genetic Engineering
- Genetic Therapy/methods
- Immunotherapy/methods
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Kidney Neoplasms/immunology
- Kidney Neoplasms/metabolism
- Kidney Neoplasms/therapy
- Leukocyte Common Antigens/immunology
- Lipids/administration & dosage
- Lung Neoplasms/immunology
- Lung Neoplasms/metabolism
- Lung Neoplasms/secondary
- Lung Neoplasms/therapy
- Mice
- Microcirculation
- Neoplasms, Experimental
- Neovascularization, Pathologic
- Peptides, Cyclic/administration & dosage
- Polyethylene Glycols/administration & dosage
- Polyethyleneimine/administration & dosage
- Polyethyleneimine/analogs & derivatives
- Transfection/methods
- Vascular Endothelial Growth Factor Receptor-2/genetics
- Vascular Endothelial Growth Factor Receptor-2/metabolism
Collapse
Affiliation(s)
- J W Yockman
- Department of Pharmaceutics and Pharmaceutical Chemistry, Center for Controlled Chemical Delivery, University of Utah, Salt Lake City, UT 84112, USA
| | | | | | | |
Collapse
|
67
|
Wang XL, Jensen R, Lu ZR. A novel environment-sensitive biodegradable polydisulfide with protonatable pendants for nucleic acid delivery. J Control Release 2007; 120:250-8. [PMID: 17582638 DOI: 10.1016/j.jconrel.2007.05.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 05/08/2007] [Accepted: 05/11/2007] [Indexed: 02/06/2023]
Abstract
Clinical application of nucleic acid-based therapies is limited by the lack of safe and efficient delivery systems. The purpose of this study is to design and evaluate novel biodegradable polymeric carriers sensitive to environmental changes for efficient delivery of nucleic acids, including plasmid DNA and siRNA. A novel polydisulfide with protonatable pendants was synthesized by the oxidative polymerization of a dithiol monomer, which was readily prepared by solid phase chemistry. The polydisulfide exhibited good buffering capacity and low cytotoxicity. It formed stable complexes with both plasmid DNA and siRNA. The particle sizes of the complexes decreased with the increase of the N/P ratios in the range of 100 to 750 nm. The complexes were stable in the presence of salt and heparin under normal physiological conditions, but dissociated to release nucleic acids in a reductive environment similar to cytoplasm. The polydisulfide demonstrated N/P ratio dependent transfection efficiency for plasmid DNA and gene silencing efficiency for siRNA. The presence of an endosomal disrupting agent, chloroquine, did not affect the DNA transfection efficiency of the polydisulfide. The transfection or gene silencing efficiency of the polydisulfide/DNA or siRNA complexes was comparable to or slightly lower than that of corresponding PEI complexes. Moreover, the polydisulfide showed better serum-friendly feature than PEI when delivering either DNA or siRNA in the presence of 10% FBS. This novel polydisulfide is a promising lead for further design and development of safe and efficient delivery systems for nucleic acids.
Collapse
Affiliation(s)
- Xu-Li Wang
- Departments of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84108, United States
| | | | | |
Collapse
|
68
|
Fischbach C, Mooney DJ. Polymers for pro- and anti-angiogenic therapy. Biomaterials 2007; 28:2069-76. [PMID: 17254631 DOI: 10.1016/j.biomaterials.2006.12.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 12/07/2006] [Indexed: 02/01/2023]
Abstract
Dysregulated growth factor signaling is traditionally targeted via bolus injections of therapeutic molecules, but this approach may not recreate necessary qualitative and quantitative aspects of biologic growth factor delivery systems. Polymeric delivery systems may, instead, mimic certain sequestration and binding characteristics of the extracellular matrix and lead to the provision of therapeutic molecules at therapeutically efficient local concentrations [V], in the form of spatial gradients (d[V]/dx) and temporal gradients (d[V]/dt), and in combination with other morphogenetic cues. Both physicochemical and biological attributes dictate their design, and they may be fabricated from synthetic and natural polymers. General concepts for manipulating growth factor signaling with these systems are discussed in the context of angiogenesis with vascular endothelial growth factor (VEGF), and these strategies may be broadly adapted to a multitude of other morphogens and growth factors.
Collapse
Affiliation(s)
- Claudia Fischbach
- Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138, USA
| | | |
Collapse
|
69
|
Persano L, Crescenzi M, Indraccolo S. Anti-angiogenic gene therapy of cancer: current status and future prospects. Mol Aspects Med 2007; 28:87-114. [PMID: 17306361 DOI: 10.1016/j.mam.2006.12.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 12/14/2022]
Abstract
The discovery of endogenous inhibitors of angiogenesis has made it possible to test the hypothesis that blocking the angiogenic switch may keep tumor growth in check, and has added a new investigational arm to the field of cancer gene therapy. Angiogenesis inhibitors are heterogeneous in origin and potency, and their growing list includes proteolysis products of larger molecules with a different function, such as angiostatin, endostatin and vasostatin, modulators of vascular endothelial growth factor activity, such as sFLT-1, and some cytokines/chemokines with marked anti-endothelial activity, such as IL-12, IFN-alpha, and CXCL10. Pre-clinical studies have clearly indicated that these factors are essentially cytostatic and that they need long-term administration in order to obtain prolonged anti-tumor effects, representing a rational basis for their delivery by a gene therapy approach. The experimental approaches attempted to date, reviewed herein, indicate overall that anti-angiogenic gene therapy has efficacy mainly as an early intervention strategy and that a better understanding of the biological mechanisms underlying resistance to angiogenesis inhibition, as well as appropriate combined treatments, are required to generate a conceptual advancement which could drive the field towards successful management of established tumors.
Collapse
Affiliation(s)
- Luca Persano
- Department of Oncology and Surgical Sciences, Oncology Section, University of Padova, Via Gattamelata, 64, 35128 Padova, Italy
| | | | | |
Collapse
|