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Meng X, Sun P, Xu H, Wang Z. Folic acid-functionalized magnetic nanoprobes via a PAMAM dendrimer/SA-biotin mediated cascade-amplifying system for the efficient enrichment of circulating tumor cells. Biomater Sci 2020; 8:6395-6403. [PMID: 33034317 DOI: 10.1039/d0bm01212b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
As a liquid biopsy, circulating tumor cells (CTCs) have great significance for the early diagnosis, timely treatment, and practical evaluation of metastasis or recurrence of cancer. However, the enrichment of rare CTCs in complex blood samples is still a significant challenge. Here, unique and highly sensitive folic acid (FA)-functionalized cascade amplification system-modified magnetic nanoparticles (MNPs) were constructed to effectively capture CTCs in whole blood. In this system, as a targeted molecule, numerous FA molecules were conjugated on the surface of PAMAM dendrimers (PAMAM-FA) (first amplification) through a polyethylene glycol (PEG) linker, which could promote the more facile binding of folate receptors (FR) on the surface of ovarian cancer cells (SKOV3 cells). Then, PAMAM-FA was further modified with biotin to fabricate biotin-PAMAM-FA (BPF), which could combine with streptavidin (SA)-modified MNPs (SMs) via the SA-biotin system to efficiently target and separate CTCs. The capture efficiency of the constructed MNPs-SA ∼ biotin-PAMAM-FA (SM@BPF) nanoprobes was 90.3% with high cell viability (∼93.2%) and minimal non-specific adsorption (∼25%). Moreover, fewer nanoprobes were absorbed on the surface of the SM@BPF-captured SKOV3 cells (one-step method) compared with the SM/BPF-captured SKOV3 cells (two-step method), which was beneficial for further biological analysis. We expect that this recognition molecule-based cascade amplification system will provide an innovative CTCs enrichment platform for the early-stage diagnosis of ovarian cancer.
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Affiliation(s)
- Xiangyu Meng
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, Jiangsu, PR China.
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Nie L, Li F, Huang X, Aguilar ZP, Wang YA, Xiong Y, Fu F, Xu H. Folic Acid Targeting for Efficient Isolation and Detection of Ovarian Cancer CTCs from Human Whole Blood Based on Two-Step Binding Strategy. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14055-14062. [PMID: 29620849 DOI: 10.1021/acsami.8b02583] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Studies regarding circulating tumor cells (CTCs) have great significance for cancer prognosis, treatment monitoring, and metastasis diagnosis. However, due to their extremely low concentration in peripheral blood, isolation and enrichment of CTCs are the key steps for early detection. To this end, targeting the folic acid receptors (FRs) on the CTC surface for capture with folic acid (FA) using bovine serum albumin (BSA)-tether for multibiotin enhancement in combination with streptavidin-coated magnetic nanoparticles (MNPs-SA) was developed for ovarian cancer CTC isolation. The streptavidin-biotin-system-mediated two-step binding strategy was shown to capture CTCs from whole blood efficiently without the need for a pretreatment process. The optimized parameters for this system exhibited an average capture efficiency of 80%, which was 25% higher than that of FA-decorated magnetic nanoparticles based on the one-step CTC separation method. Moreover, the isolated cells remained highly viable and were cultured directly without detachment from the MNPs-SA-biotin-CTC complex. Furthermore, when the system was applied for the isolation and detection of CTCs in ovarian cancer patients' peripheral blood samples, it exhibited an 80% correlation with clinical diagnostic criteria. The results indicated that FA targeting, in combination with BSA-based multibiotin enhancement magnetic nanoparticle separation, is a promising tool for CTC enrichment and detection of early-stage ovarian cancer.
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Affiliation(s)
- Liju Nie
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
- The Second Affiliated Hospital of Nanchang University , Nanchang 330006 , China
- Jiangxi Maternal and Child Health Hospital , Nanchang 330000 , China
| | - Fulai Li
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
| | - Xiaolin Huang
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
| | | | | | - Yonghua Xiong
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
| | - Fen Fu
- The Second Affiliated Hospital of Nanchang University , Nanchang 330006 , China
| | - Hengyi Xu
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
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Reissmann S. Cell penetration: scope and limitations by the application of cell-penetrating peptides. J Pept Sci 2014; 20:760-84. [DOI: 10.1002/psc.2672] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Siegmund Reissmann
- Friedrich Schiller University, Biological and Pharmaceutical Faculty; Institute of Biochemistry and Biophysics; Dornburger Strasse 25 07743 Jena Germany
- Jena Bioscience GmbH; Loebstedter Strasse 80 07749 Jena Germany
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Kim SM, Choi N, Hwang S, Yim MS, Lee JS, Lee SM, Cho G, Ryu EK. Folate Receptor-Specific Positron Emission Tomography Imaging with Folic Acid-Conjugated Tissue Inhibitor of Metalloproteinase-2. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.11.3243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mussbach F, Franke M, Zoch A, Schaefer B, Reissmann S. Transduction of peptides and proteins into live cells by cell penetrating peptides. J Cell Biochem 2011; 112:3824-33. [DOI: 10.1002/jcb.23313] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Zhao H, Duong HHP, Yung LYL. Folate-Conjugated Polymer Micelles with pH-Triggered Drug Release Properties. Macromol Rapid Commun 2010; 31:1163-9. [PMID: 21590870 DOI: 10.1002/marc.200900876] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 02/01/2010] [Indexed: 11/11/2022]
Abstract
Folate has been applied as a targeting moiety for various anticancer drug-delivery agents to avoid non-specific attack of normal tissues as well as to increase cellular uptake at the target tumor cells. Polymer micelles made of poly[(D,L-lactide)-co-glycolide)]-poly(ethylene glycol)-folate (PLGA-PEG-FOL) was fabricated as a tumor targeting carrier for encapsulating the anticancer drug doxorubicin. To accelerate the drug release in the endosome after folate-mediated cellular uptake, pH-sensitive poly(β-amino ester)-PEG-FOL (PAE-PEG-FOL) was added together with PLGA-PEG-FOL to form mixed micelles. The results showed that the drug release can be triggered at different pH due to the ionization of PAE. The IC(50) of PLGA-PEG-FOL micelles is 0.46 × 10(-6) M. With 20% PAE in the mixed micelles (20:80 mixed micelles), the IC(50) decreases to 0.34 × 10(-6) M, which is comparable to that of pure PAE-PEG-FOL micelles at pH 7.4. As a result of the pH sensitivity, the PAE-PEG-FOL micelles are not stable at pH 6.5 or lower, and the drug may be released from the micelles into the extracellular environment before uptake by the cells. The 20:80 mixed micelles are relatively stable at this condition. As a result, the micelles retain more drug in the micelles for a higher degree of cellular uptake by folate receptor-mediated endocytosis, and exhibit higher cytotoxicity.
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Affiliation(s)
- Haizheng Zhao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 119260, Singapore
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Zhao H, Yung LYL. Addition of TPGS to folate-conjugated polymer micelles for selective tumor targeting. J Biomed Mater Res A 2009; 91:505-18. [DOI: 10.1002/jbm.a.32220] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Müller C, Schibli R, Forrer F, Krenning EP, de Jong M. Dose-dependent effects of (anti)folate preinjection on 99mTc-radiofolate uptake in tumors and kidneys. Nucl Med Biol 2007; 34:603-8. [PMID: 17707799 DOI: 10.1016/j.nucmedbio.2007.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 05/25/2007] [Accepted: 06/06/2007] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The folate receptor (FR) is frequently overexpressed in tumors and can be targeted with folate-based (radio)pharmaceuticals. However, significant accumulation of radiofolates in FR-positive kidneys represents a drawback. We have shown that preadministration of the antifolate pemetrexed (PMX) significantly improved the tumor-to-kidney ratio of radiofolates in mice. The aim of this study was to investigate the dose dependence of these effects and whether the same results could be achieved with folic acid (FA) or 5-methyl-tetrahydrofolate (5-Me-THF). METHODS Biodistribution was assessed 4 h postinjection of the organometallic (99m)Tc-picolylamine monoacetic acid folate in nude mice bearing FR-positive KB tumor xenografts. PMX (50-400 microg/mouse) was injected 1 h previous to radioactivity. The effects of FA and 5-Me-THF (0.5-50 microg/mouse) were investigated likewise. Tissues and organs were collected and counted for radioactivity and the values tabulated as percentage of injected dose per gram tissue (% ID/g). RESULTS PMX administration reduced renal retention (<1.6% ID/g vs. control: >10% ID/g), while the tumor uptake (average 1.35%+/-0.40% ID/g vs. control: 1.79%+/-0.49% ID/g) was only slightly affected independent of the PMX dose. Replacement of PMX by FA or 5-Me-THF (50 microg/mouse) resulted in a significant renal blockade (<0.1% ID/g) but at the same time in an undesired reduction of tumor uptake (<0.2% ID/g). CONCLUSIONS Selective reduction of radiofolate uptake in kidneys under retention of high tumor accumulation could be achieved in combination with PMX over a broad dose range but not with FA or 5-Me-THF.
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Affiliation(s)
- Cristina Müller
- Department of Nuclear Medicine, Erasmus MC, 3015 CE Rotterdam, The Netherlands.
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Henne WA, Doorneweerd DD, Hilgenbrink AR, Kularatne SA, Low PS. Synthesis and activity of a folate peptide camptothecin prodrug. Bioorg Med Chem Lett 2006; 16:5350-5. [PMID: 16901694 DOI: 10.1016/j.bmcl.2006.07.076] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 07/24/2006] [Indexed: 10/24/2022]
Abstract
A folate receptor targeted camptothecin prodrug was synthesized using a hydrophilic peptide spacer linked to folate via a releasable disulfide carbonate linker. The conjugate was found to possess high affinity for folate receptor-expressing cells and inhibited cell proliferation in human KB cells with an IC(50) of 10nM. Activity of the prodrug was completely blocked by excess folic acid, demonstrating receptor-mediated uptake.
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Affiliation(s)
- Walter A Henne
- Department of Chemistry and Purdue Cancer Center, Purdue University, West Lafayette, IN 47907, USA
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Lu Y, Yang J, Sega E. Issues related to targeted delivery of proteins and peptides. AAPS JOURNAL 2006; 8:E466-78. [PMID: 17025264 PMCID: PMC2761053 DOI: 10.1208/aapsj080355] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
While modern genomic and proteomic technology enables rapid screening of novel proteins and peptides as potential drug candidates, design of delivery systems for these biologics remains challenging especially to achieve site-specific pharmacological actions. This article discusses the issues associated with targeted delivery of protein and peptide drugs at physiochemical, physiological, and intracellular levels with a special focus on cancer therapy.
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Affiliation(s)
- Yingjuan Lu
- Endocyte, Inc, 3000 Kent Avenue, Suite A1-100, West Lafayette, IN 47906, USA.
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Hilgenbrink AR, Low PS. Folate Receptor-Mediated Drug Targeting: From Therapeutics to Diagnostics. J Pharm Sci 2005; 94:2135-46. [PMID: 16136558 DOI: 10.1002/jps.20457] [Citation(s) in RCA: 448] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Folate targeted drug delivery has emerged as an alternative therapy for the treatment and imaging of many cancers and inflammatory diseases. Due to its small molecular size and high binding affinity for cell surface folate receptors (FR), folate conjugates have the ability to deliver a variety of molecular complexes to pathologic cells without causing harm to normal tissues. Complexes that have been successfully delivered to FR expressing cells, to date, include protein toxins, immune stimulants, chemotherapeutic agents, liposomes, nanoparticles, and imaging agents. This review will summarize the applications of folic acid as a targeting ligand and highlight the various methods being developed for delivery of therapeutic and imaging agents to FR-expressing cells.
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Read ML, Logan A, Seymour LW. Barriers to Gene Delivery Using Synthetic Vectors. ADVANCES IN GENETICS 2005; 53PA:19-46. [PMID: 16243059 DOI: 10.1016/s0065-2660(05)53002-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Progress has been made in the development of different types of nucleic acids such as DNA and siRNA with the potential to form the basis of new treatments for genetic and acquired disorders. The lack of suitable vectors for the delivery of nucleic acids, however, represents a major hurdle to their continued development and therapeutic application. Synthetic vectors based on polycations are promising vectors for gene delivery as they are relatively safe and can be modified by the incorporation of ligands for targeting to specific cell types. However, the levels of gene expression mediated by synthetic vectors are low compared to viral vectors. The aim of this chapter is to give an overview of the main barriers that have been identified as limiting gene transfer using polycation-based synthetic vectors. The chapter is divided into two sections to focus on both extracellular and intracellular barriers. We describe novel strategies that are being used to develop increasingly sophisticated vectors in an attempt to overcome these barriers. For instance, we describe approaches to prolong the plasma circulation of polyplexes by the incorporation onto their surface of hydrophilic polymers such as polyethylene glycol (PEG) and poly[N-(2-hydroxypropyl)methacrylamide] (pHPMA). In addition, strategies to improve transfer of nucleic acids from the outside of the cell to the nucleus are described to overcome barriers such as escape from endocytic vesicles and translocation across the nuclear membrane. Furthermore, we highlight new types of vectors based on reducible polycations that are triggered by the intracellular environment to facilitate efficient cytoplasmic release of nucleic acids.
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Affiliation(s)
- Martin L Read
- Molecular Neuroscience Group, Department of Medicine Wolfson Research Laboratories University of Birmingham Birmingham, B15 2TH, United Kingdom
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Müller C, Dumas C, Hoffmann U, Schubiger PA, Schibli R. Organometallic 99mTc-technetium(I)- and Re-rhenium(I)-folate derivatives for potential use in nuclear medicine. J Organomet Chem 2004. [DOI: 10.1016/j.jorganchem.2004.08.045] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ke CY, Mathias CJ, Green MA. The folate receptor as a molecular target for tumor-selective radionuclide delivery. Nucl Med Biol 2003; 30:811-7. [PMID: 14698784 DOI: 10.1016/s0969-8051(03)00117-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The cell-membrane folate receptor is a potential molecular target for tumor-selective drug delivery, including radiolabeled folate-chelate conjugates for diagnostic imaging. We review here some background on the folate receptor as tumor-associated molecular target for drug delivery, and briefly survey the literature on tumor-targeting with radiolabeled folate-chelate conjugates.
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Affiliation(s)
- Chun-Yen Ke
- Department of Industrial and Physical Pharmacy, Purdue University, West, Lafayette, IN 47907-2091, USA
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Mathias CJ, Lewis MR, Reichert DE, Laforest R, Sharp TL, Lewis JS, Yang ZF, Waters DJ, Snyder PW, Low PS, Welch MJ, Green MA. Preparation of 66Ga- and 68Ga-labeled Ga(III)-deferoxamine-folate as potential folate-receptor-targeted PET radiopharmaceuticals. Nucl Med Biol 2003; 30:725-31. [PMID: 14499330 DOI: 10.1016/s0969-8051(03)00080-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A folate-receptor-targeting radiopharmaceutical, Ga(III)-deferoxamine-folate (Ga-DF-Folate), was radiolabeled with two positron-emitting isotopes of gallium, cyclotron-produced (66)Ga (9.5 hour half-life) and generator-produced (68)Ga (68 minute half-life). The [(66)Ga]Ga-DF-Folate was administered to athymic mice with folate-receptor-positive human KB cell tumor xenografts to demonstrate that microPET mouse tumor imaging is feasible with (66)Ga, despite the relatively high positron energy of this radionuclide. Using the athymic mouse KB tumor xenograft model, dual-isotope autoradiography was also performed following i.v. co-administration of [(18)F]-FDG, a marker of regional metabolic activity, and folate-receptor-targeted [(111)In]In-DTPA-Folate. The autoradiographic images of 1 mm tumor sections demonstrate the gross heterogeneity of the KB cell tumor xenograft, as well as subtle disparity in the regional accumulation of the two radiotracers.
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Affiliation(s)
- Carla J Mathias
- Department of Industrial and Physical Pharmacy, Purdue University, West, Lafayette, IN, USA
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Song SC, Lee SB, Lee BH, Ha HW, Lee KT, Sohn YS. Synthesis and antitumor activity of novel thermosensitive platinum(II)-cyclotriphosphazene conjugates. J Control Release 2003; 90:303-11. [PMID: 12880697 DOI: 10.1016/s0168-3659(03)00199-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Thermosensitive cyclotriphosphazenes bearing alkoxy poly(ethylene glycol) and amino acid esters as side groups could be functionalized to chelate the antitumor (diamine)platinum(II) moiety through the dicarboxylate group of the amino acid substituent on the cyclic phosphazene ring. Surprisingly, like the precursor cyclotriphosphazenes, these (diamine)platinum(II)-cyclotriphosphazene conjugates were also found to exhibit variable lower critical solution temperatures (LCST) in the wide range of 12 to 92 degrees C. Furthermore, the present conjugates have shown outstanding in vitro and in vivo antitumor activities due to controlled release of the antitumor (diamine)platinum(II) moiety with hydrolytic degradation of the phosphazene ring. A few of these conjugates have shown LCSTs below body temperature, and it has been shown from a model animal experiment that the conjugates with a LCST below body temperature may be applied to local drug delivery by direct intratumoral injection.
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Affiliation(s)
- Soo-Chang Song
- Division of Life Science, Korea Institute of Science & Technology, 130-650 Seoul, South Korea
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Abstract
The receptor for folic acid constitutes a useful target for tumor-specific drug delivery, primarily because: (1) it is upregulated in many human cancers, including malignancies of the ovary, brain, kidney, breast, myeloid cells and lung, (2) access to the folate receptor in those normal tissues that express it can be severely limited due to its location on the apical (externally-facing) membrane of polarized epithelia, and (3) folate receptor density appears to increase as the stage/grade of the cancer worsens. Thus, cancers that are most difficult to treat by classical methods may be most easily targeted with folate-linked therapeutics. To exploit these peculiarities of folate receptor expression, folic acid has been linked to both low molecular weight drugs and macromolecular complexes as a means of targeting the attached molecules to malignant cells. Conjugation of folic acid to macromolecules has been shown to enhance their delivery to folate receptor-expressing cancer cells in vitro in almost all situations tested. Folate-mediated macromolecular targeting in vivo has, however, yielded only mixed results, largely because of problems with macromolecule penetration of solid tumors. Nevertheless, prominent examples do exist where folate targeting has significantly improved the outcome of a macromolecule-based therapy, leading to complete cures of established tumors in many cases. This review presents a brief mechanistic background of folate-targeted macromolecular therapeutics and then summarizes the successes and failures observed with each major application of the technology.
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Affiliation(s)
- Yingjuan Lu
- Department of Chemistry, 1393 Brown Building, Purdue University, West Lafayette, IN 47907, USA
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Ward CM, Pechar M, Oupicky D, Ulbrich K, Seymour LW. Modification of pLL/DNA complexes with a multivalent hydrophilic polymer permits folate-mediated targeting in vitro and prolonged plasma circulation in vivo. J Gene Med 2002; 4:536-47. [PMID: 12221647 DOI: 10.1002/jgm.296] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Gene delivery vectors based on poly(L-lysine) and DNA (pLL/DNA complexes) have limited use for targeted systemic application in vivo since they bind cells and proteins non-specifically. In this study we have attempted to form folate-targeted vectors with extended systemic circulation by surface modification of pLL/DNA complexes with hydrophilic polymers. METHODS pLL/DNA complexes were stabilised by surface modification with a multivalent reactive polymer based on alternating segments of poly(ethylene glycol) and tripeptides bearing reactive ester groups. Folate moieties were incorporated into the vectors either by direct attachment of folate to the polymer or via intermediate poly(ethylene glycol) spacers of 800 and 3400 Da. RESULTS Polymer-coated complexes show similar morphology to uncoated complexes, their zeta potential is decreased towards zero, serum protein binding is inhibited and aqueous solubility is substantially increased. Intravenous (i.v.) administration to mice of coated complexes produced extended systemic circulation, with up to 2000-fold more DNA measured in the bloodstream after 30 min compared with simple pLL/DNA complexes. In further contrast to simple pLL/DNA complexes, coated complexes do not bind blood cells in vivo. Folate receptor targeting is shown to mediate targeted association with HeLa cells in vitro, leading to increased transgene expression. We demonstrate for the first time that DNA uptake via the folate receptor is dependent on pEG spacer length, with the transgene expression relatively independent of the level of internalised DNA. CONCLUSIONS We show increased systemic circulation, decreased blood cell and protein binding, and folate-targeted transgene expression using pLL/DNA complexes surface-modified with a novel multireactive hydrophilic polymer. This work provides the basis for the development of plasma-circulating targeted vectors for in vivo applications.
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Affiliation(s)
- Christopher M Ward
- Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK.
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Abstract
Recent progress in understanding the molecular basis of cancer brought out new materials such as oligonucleotides, genes, peptides and proteins as a source of new anticancer agents. Due to their macromolecular properties, however, new strategies of delivery for them are required to achieve their full therapeutic efficacy in clinical setting. Development of improved dosage forms of currently marketed anticancer drugs can also enhance their therapeutic values. Currently developed delivery systems for anticancer agents include colloidal systems (liposomes, emulsions, nanoparticles and micelles), polymer implants and polymer conjugates. These delivery systems have been able to provide enhanced therapeutic activity and reduced toxicity of anticancer agents mainly by altering their pharmacokinetics and biodistribution. Furthermore, the identification of cell-specific receptor/antigens on cancer cells have brought the development of ligand- or antibody-bearing delivery systems which can be targeted to cancer cells by specific binding to receptors or antigens. They have exhibited specific and selective delivery of anticancer agents to cancer. As a consequence of extensive research, clinical development of anticancer agents utilizing various delivery systems is undergoing worldwide. New technologies and multidisciplinary expertise to develop advanced drug delivery systems, applicable to a wide range of anticancer agents, may eventually lead to an effective cancer therapy in the future.
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Affiliation(s)
- Chong-Kook Kim
- National Research Lab for Drug and Gene Delivery, College of Pharmacy, Seoul National University, Kwanak-Gu, Korea.
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Konda SD, Wang S, Brechbiel M, Wiener EC. Biodistribution of a 153 Gd-folate dendrimer, generation = 4, in mice with folate-receptor positive and negative ovarian tumor xenografts. Invest Radiol 2002; 37:199-204. [PMID: 11923642 DOI: 10.1097/00004424-200204000-00005] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVES An important characteristic of targeted contrast agents is how they are tolerated in a biologic environment and their localization in the surrounding tissues in addition to target tissue. We evaluate the biodistribution of a gadolinium Gd 153-folate-dendrimer in high affinity folate-receptor (hFR) positive and negative ovarian tumor xenografts. METHODS The 153Gd-folate-dendrimer chelate was prepared by exchanging 153Gd with nonradioactive gadolinium for 1 week, followed by extensive filtration. Athymic mice with hFR-positive (n = 3) and negative tumors (n = 3) were injected intravenously and counted using a whole-body counting system with a 80 to 150 keV counting window. RESULTS The hFR-positive tumors accumulate 3.6% +/- 2.8% injected dose/g, whereas only background counts were found in hFR-negative tumors. The folate-dendrimer's tumor-to-blood ratio of 12.6, in hFR-positive tumors, was approximately 5.7 to 17.0 fold better than those obtained with monoclonal antibodies targeted to the folate receptor. CONCLUSIONS Biodistribution studies confirm previous MRI findings and show that the accumulation of the folate-dendrimer requires the expression of the hFR.
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Atkinson SF, Bettinger T, Seymour LW, Behr JP, Ward CM. Conjugation of folate via gelonin carbohydrate residues retains ribosomal-inactivating properties of the toxin and permits targeting to folate receptor positive cells. J Biol Chem 2001; 276:27930-5. [PMID: 11359781 DOI: 10.1074/jbc.m102825200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conjugation of folate to proteins permits receptor-mediated endocytosis via the folate receptor (FR) and delivery of the conjugate into the cytoplasm of cells. Since many cancers up-regulate the FR it has enabled the targeting of toxins to tumor cells resulting in specific cell death. However, current conjugation methods rely on chemistries that can affect certain catalytic subunits, such as the A-chain of the plant toxin gelonin. As a result many folate-targeted toxins are a compromise between receptor/ligand interaction and toxin activity. We describe the first example of folate conjugated to a protein via carbohydrate residues, using a novel SH-folate intermediate. The folate-gelonin conjugate retains over 99% of toxin activity in a cell-free translational assay compared with unmodified gelonin and is able to bind the FR at the same affinity as free folic acid (10(-10) m). Additionally, the conjugate exhibits prolonged inhibition of protein synthesis in FR positive cell lines in vitro. Folate linked to gelonin via amino conjugation exhibits the same affinity for FR as free folic acid but the toxin is 225-fold less active in a cell-free translational assay. The effect of different conjugation methods on toxin activity and the implications for folate targeting of other glycoproteins are discussed.
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Affiliation(s)
- S F Atkinson
- CRC Institute for Cancer Studies, University of Birmingham, Birmingham, B15 2TA United Kingdom
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Abstract
The covalent attachment of the vitamin folic acid to almost any molecule yields a conjugate that can be endocytosed into folate receptor-bearing cells. Because folate receptors are significantly overexpressed in the majority of human cancers, this methodology is currently being investigated for the selective delivery of imaging and therapeutic agents to tumor tissue. Phase I and II clinical studies for the first folate-containing imaging agent were initiated in 1999, and clinical trials of folate-targeted therapeutic agents should soon follow. This review will summarize folate-mediated drug delivery and highlight those techniques undergoing active preclinical or clinical investigation.
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Affiliation(s)
- C P. Leamon
- Endocyte Pharmaceuticals, 1205 Kent Avenue, 47906, West Lafayette, IN, USA
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