101
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Oh JM, Choi SJ, Lee GE, Kim JE, Choy JH. Inorganic Metal Hydroxide Nanoparticles for Targeted Cellular Uptake Through Clathrin-Mediated Endocytosis. Chem Asian J 2009; 4:67-73. [DOI: 10.1002/asia.200800290] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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102
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Preparation and identification of scFv and bsFv against transferrin receptor. ACTA ACUST UNITED AC 2008; 28:621-5. [PMID: 19107352 DOI: 10.1007/s11596-008-0601-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Indexed: 10/19/2022]
Abstract
To obtain single chain variable fragment (scFv) and bivalent single chain variable fragment (bsFv) against transferrin receptor, up-stream and down-stream primers were designed according to the complementary sequences of FR1 region of variable heavy (VH) and FR4 of variable light (VL), respectively, which contained inter-linker G4S and the restriction endonuclease SfiI, AscI and NotI. Two pieces of scFv fragments were first amplified through PCR and then inserted into plasmid pAB1, which could express scFv protein once induced by IPTG in the host bacteria. To express scFv and bsFv, E. coli TG1 was cultured in LB broth and was induced by IPTG. The restriction enzyme digestion map and DNA sequencing demonstrated that scFv and bsFv genes were successfully inserted into the expression plasmid. SDS-PAGE and Western blotting revealed the protein band at 35kD and 60kD, which were consistent with the molecular weight of scFv and bsFv respectively. Flow cytometry showed that scFv and bsFv harbored the specific binding activity with TfR expressed in various tumor cells, and the avidity of bsFv was higher than that of the parent scFv.
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103
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Torchilin VP. Cell penetrating peptide-modified pharmaceutical nanocarriers for intracellular drug and gene delivery. Biopolymers 2008; 90:604-10. [PMID: 18381624 DOI: 10.1002/bip.20989] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cell-penetrating peptides (CPPs) including TAT peptide (TATp) have been successfully used for intracellular delivery of a broad variety of cargos including various nanoparticulate pharmaceutical carriers (liposomes, micelles, nanoparticles). Here, we will consider the main results in this area, with a special emphasis on TATp-mediated delivery of liposomes and DNA. We will also address the development of "smart" stimuli-sensitive nanocarriers, where cell-penetrating function can be activated by the decreased pH only inside the biological target minimizing thus the interaction of drug-loaded nanocarriers with nontarget cells.
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Affiliation(s)
- Vladimir P Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA 02115.
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104
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Torchilin V. Multifunctional and stimuli-sensitive pharmaceutical nanocarriers. Eur J Pharm Biopharm 2008; 71:431-44. [PMID: 18977297 DOI: 10.1016/j.ejpb.2008.09.026] [Citation(s) in RCA: 441] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 08/29/2008] [Accepted: 09/02/2008] [Indexed: 11/26/2022]
Abstract
Currently used pharmaceutical nanocarriers, such as liposomes, micelles, and polymeric nanoparticles, demonstrate a broad variety of useful properties, such as longevity in the body; specific targeting to certain disease sites; enhanced intracellular penetration; contrast properties allowing for direct carrier visualization in vivo; stimuli-sensitivity, and others. Some of those pharmaceutical carriers have already made their way into clinic, while others are still under preclinical development. In certain cases, the pharmaceutical nanocarriers combine several of the listed properties. Long-circulating immunoliposomes capable of prolonged residence in the blood and specific target recognition represent one of the examples of this kind. The engineering of multifunctional pharmaceutical nanocarriers combining several useful properties in one particle can significantly enhance the efficacy of many therapeutic and diagnostic protocols. This paper considers the current status and possible future directions in the emerging area of multifunctional nanocarriers with primary attention on the combination of such properties as longevity, targetability, intracellular penetration, contrast loading, and stimuli-sensitivity.
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Affiliation(s)
- Vladimir Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, MA 02115, USA
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105
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Torchilin VP. Tat peptide-mediated intracellular delivery of pharmaceutical nanocarriers. Adv Drug Deliv Rev 2008; 60:548-58. [PMID: 18053612 DOI: 10.1016/j.addr.2007.10.008] [Citation(s) in RCA: 327] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 10/01/2007] [Indexed: 12/16/2022]
Abstract
Cell-penetrating peptides (CPPs) including TAT peptide (TATp) have been successfully used for intracellular delivery of a broad variety of cargoes including various nanoparticulate pharmaceutical carriers (liposomes, micelles, nanoparticles). Here, we will consider the main results in this area, with a special emphasis on TATp-mediated delivery of liposomes and DNA. We will also address the development of "smart" stimuli-sensitive nanocarriers, where cell-penetrating function can be activated by the decreased pH only inside the biological target minimizing thus the interaction of drug-loaded nanocarriers with non-target cells.
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106
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Norouziyan F, Shen WC, Hamm-Alvarez SF. Tyrphostin A8 stimulates a novel trafficking pathway of apically endocytosed transferrin through Rab11-enriched compartments in Caco-2 cells. Am J Physiol Cell Physiol 2007; 294:C7-21. [PMID: 17959726 DOI: 10.1152/ajpcell.00372.2006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The potential application of transferrin receptors as delivery vehicles for transport of macromolecular drugs across intestinal epithelial cells is limited by several factors, including the low level of transferrin receptor-mediated transcytosis, particularly in the apical-to-basolateral direction. The GTPase inhibitor, AG10 (tyrphostin A8), has been shown previously to increase the apical-to-basolateral transcytosis of transferrin in Caco-2 cells. However, the mechanism of the increased transcytosis has not been established. In this report, the effect of AG10 on the trafficking of endocytosed transferrin among different endosomal compartments as well as the involvement of Rab11 in the intracellular trafficking of transferrin was investigated. Confocal microscopy studies showed a high level of colocalization of FITC-transferrin with Rab5 and Rab11 in Caco-2 cells pulsed at 16 degrees C and 37 degrees C, which indicated the presence of apically endocytosed FITC-transferrin in early endosomes and apical recycling endosomes at 16 degrees C and 37 degrees C, respectively. The effect of AG10 on the accumulation of transferrin within different endosomal compartment was studied, and an increase in the transcytosis and recycling of internalized (125)I-labeled transferrin, as well as a decrease in cell-associated (125)I-labeled transferrin, was observed in AG10-treated Caco-2 cells pulsed at 37 degrees C for 30 min and chased for 30 min. Moreover, confocal microscopy showed that FITC-transferrin exhibited an increased level of colocalization with Rab11, but not with Rab5, in the presence of AG10. These results suggest an effect of AG10 on the later steps of transferrin receptor trafficking, which are involved in subsequent recycling, and possibly transcytosis, of endocytosed transferrin in Caco-2 cells.
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Affiliation(s)
- Fariba Norouziyan
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90033, USA
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107
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Abstract
CPPs (cell-penetrating peptides), including Tatp (transactivator of transcription peptide), have been successfully used for intracellular delivery of a wide variety of cargoes including various nanoparticulate pharmaceutical carriers such as liposomes, micelles and nanoparticles. Here, we will consider the major results obtained in this area with emphasis on Tatp-mediated delivery of liposomes and various transfection vectors. We will also address the development of ‘smart’ stimuli-sensitive nanocarriers, where the cell-penetrating function can only be activated when the nanocarrier is inside the biological target, thus minimizing the interaction with non-target cells.
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Affiliation(s)
- V P Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA 02115, USA.
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108
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Kakimoto S, Moriyama T, Tanabe T, Shinkai S, Nagasaki T. Dual-ligand effect of transferrin and transforming growth factor alpha on polyethyleneimine-mediated gene delivery. J Control Release 2007; 120:242-9. [PMID: 17574290 DOI: 10.1016/j.jconrel.2007.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 04/21/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
In order to enhance the internalization of exogenous gene and add cell specificity to non-viral vectors, receptor-binding elements have been widely utilized to mimic the virus infection. Herein, for the purpose of intensifying the effects of the ligand on gene delivery, dual receptor-binding elements, transferrin (Tf) and transforming growth factor alpha (TGFalpha), were introduced into the polyethyleneimine polyplex. The transfection and internalization efficiency by dual Tf- and TGFalpha-introduced polyplex (Tf&TGFalpha-polyplex) was examined in A549 and CHO-K1 cells, respectively. In A549, Tf&TGFalpha-polyplex had higher transfection efficiency when compared to that by single Tf- or TGFalpha-introduced polyplex (Tf-polyplex and TGFalpha-polyplex), respectively, while no enhancement was observed in CHO-K1. Moreover, in A549, the internalization efficiency of dual Tf&TGFalpha-polyplex was higher than that of single Tf- and TGFalpha-polyplex. In contrast, in CHO-K1, no difference in internalization efficiency was observed. In the presence of excess free transferrin or TGFalpha, the internalization efficiency of Tf&TGFalpha-polyplex was strongly inhibited only in A549, not in CHO-K1. In summary, the enhancement of internalization efficiency by dual ligands is an important factor for improving transfection efficiency. In addition, the effect of dual ligands depends on cell species; receptor-mediated and efficient internalization may be related to this enhanced transfection efficiency.
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Affiliation(s)
- Shinji Kakimoto
- Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, Japan
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109
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Chithrani BD, Chan WCW. Elucidating the mechanism of cellular uptake and removal of protein-coated gold nanoparticles of different sizes and shapes. NANO LETTERS 2007; 7:1542-50. [PMID: 17465586 DOI: 10.1021/nl070363y] [Citation(s) in RCA: 1556] [Impact Index Per Article: 91.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We investigated the mechanism by which transferrin-coated gold nanoparticles (Au NP) of different sizes and shapes entered mammalian cells. We determined that transferrin-coated Au NP entered the cells via clathrin-mediated endocytosis pathway. The NPs exocytosed out of the cells in a linear relationship to size. This was different than the relationship between uptake and size. Furthermore, we developed a mathematical equation to predict the relationship of size versus exocytosis for different cell lines. These studies will provide guidelines for developing NPs for imaging and drug delivery applications, which will require "controlling" NP accumulation rate. These studies will also have implications in determining nanotoxicity.
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Affiliation(s)
- B Devika Chithrani
- Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, 160 College Street, 4th Floor, Toronto, Ontario M5S 3G9, Canada
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110
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Lim CJ, Norouziyan F, Shen WC. Accumulation of transferrin in Caco-2 cells: a possible mechanism of intestinal transferrin absorption. J Control Release 2007; 122:393-8. [PMID: 17586083 PMCID: PMC2128747 DOI: 10.1016/j.jconrel.2007.03.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 03/25/2007] [Accepted: 03/30/2007] [Indexed: 11/18/2022]
Abstract
Transferrin receptor (TfR)-mediated endocytosis and transcytosis in enterocyte-like Caco-2 cells was investigated in order to elucidate the transport mechanism of orally administered Tf-fusion proteins. Cellular uptake and pulse chase studies were performed in Caco-2, MCF-7 and bladder carcinoma (5637) cells using 125I-labeled Tf (125I-Tf). Co-localization studies of Rab 11 and FITC-Tf endocytosed at either the apical or basolateral membrane were performed in polarized Caco-2 cells grown on Transwells, using confocal laser scanning microscopy (LSM510, Zeiss). Unlike in MCF-7 or 5637 cells, where rapid recycling of Tf was observed, a significant amount of endocytosed 125I-Tf accumulated in Caco-2 cells. This accumulation was especially noticeable with the internalization of 125I-Tf from the apical membrane of polarized Caco-2 cells. Confocal microscopy studies showed that apically, but not basolaterally, endocytosed FITC-Tf was delivered to a Rab11-positive compartment. Our results suggest that a significant amount of apically endocytosed Tf in intestinal epithelial cells is transported to a Rab11-positive compartment, possibly a late endosomal and slow recycling compartment. The Rab11-positive compartment may control the release of apically internalized Tf for either slow recycling to apical membrane or processing to transcytotic compartments.
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Affiliation(s)
- Ching-Jou Lim
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
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111
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Oh JM, Choi SJ, Kim ST, Choy JH. Cellular uptake mechanism of an inorganic nanovehicle and its drug conjugates: Enhanced efficacy due to clathrin-mediated endocytosis. Bioconjug Chem 2007; 17:1411-7. [PMID: 17105218 DOI: 10.1021/bc0601323] [Citation(s) in RCA: 209] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We present the mechanism for the cellular uptake of layered double hydroxide (LDH) nanoparticles that are internalized into MNNG/HOS cells principally via clathrin-mediated endocytosis. The intracellular LDHs are highly colocalized with not only typical endocytic proteins, such as clathrin heavy chain, dynamin, and eps15, but also transferrin, a marker of the clathrin-mediated process, suggesting their specific internalization pathway. LDHs loaded with an anticancer drug (MTX-LDH) were also prepared to confirm the efficacy of LDHs as drug delivery systems. The cellular uptake of MTX was higher in MTX-LDH-treated cells than in MTX-treated cells, giving a lower IC50 value for MTX-LDH than for MTX only. The inhibition of the cell cycle was greater for MTX-LDH than for MTX only. This result clearly shows that the internalization of LDH nanoparticles via clathrin-mediated endocytosis may allow the efficient delivery of MTX-LDH in cells and thus enhance drug efficacy.
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Affiliation(s)
- Jae-Min Oh
- Center for Intelligent Nano-Bio Materials, Division of Nanoscience and Department of Chemistry, Ewha Womans University, Seoul 120-750, Korea
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112
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Sawant RM, Hurley JP, Salmaso S, Kale A, Tolcheva E, Levchenko TS, Torchilin VP. "SMART" drug delivery systems: double-targeted pH-responsive pharmaceutical nanocarriers. Bioconjug Chem 2006; 17:943-9. [PMID: 16848401 PMCID: PMC2538444 DOI: 10.1021/bc060080h] [Citation(s) in RCA: 448] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To develop targeted pharmaceutical carriers additionally capable of responding to certain local stimuli, such as decreased pH values in tumors or infarcts, targeted long-circulating PEGylated liposomes and PEG-phosphatidylethanolamine (PEG-PE)-based micelles have been prepared with several functions. First, they are capable of targeting a specific cell or organ by attaching the monoclonal antimyosin antibody 2G4 to their surface via pNP-PEG-PE moieties. Second, these liposomes and micelles were additionally modified with biotin or TAT peptide (TATp) moieties attached to the surface of the nanocarrier by using biotin-PE or TATp-PE or TATp-short PEG-PE derivatives. PEG-PE used for liposome surface modification or for micelle preparation was made degradable by inserting the pH-sensitive hydrazone bond between PEG and PE (PEG-Hz-PE). Under normal pH values, biotin and TATp functions on the surface of nanocarriers were "shielded" by long protecting PEG chains (pH-degradable PEG(2000)-PE or PEG(5000)-PE) or by even longer pNP-PEG-PE moieties used to attach antibodies to the nanocarrier (non-pH-degradable PEG(3400)-PE or PEG(5000)-PE). At pH 7.4-8.0, both liposomes and micelles demonstrated high specific binding with 2G4 antibody substrate, myosin, but very limited binding on an avidin column (biotin-containing nanocarriers) or internalization by NIH/3T3 or U-87 cells (TATp-containing nanocarriers). However, upon brief incubation (15-30 min) at lower pH values (pH 5.0-6.0), nanocarriers lost their protective PEG shell because of acidic hydrolysis of PEG-Hz-PE and acquired the ability to become strongly retained on an avidin column (biotin-containing nanocarriers) or effectively internalized by cells via TATp moieties (TATp-containing nanocarriers). We consider this result as the first step in the development of multifunctional stimuli-sensitive pharmaceutical nanocarriers.
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Affiliation(s)
- R M Sawant
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, USA
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113
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Wüstner D. Quantification of polarized trafficking of transferrin and comparison with bulk membrane transport in hepatic cells. Biochem J 2006; 400:267-80. [PMID: 16879100 PMCID: PMC1652827 DOI: 10.1042/bj20060626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transport of the recycling marker transferrin was analysed in polarized hepatic HepG2 cells using quantitative fluorescence microscopy and mathematical modelling. A detailed map and kinetic model for transport of transferrin in hepatic cells was developed. Fluorescent transferrin was found to be transported sequentially through basolateral SE (sorting endosomes) to a SAC/ARC (subapical compartment/apical recycling compartment). DiI (di-indocarbocyanine) lipid probes of different acyl chain length (DiIC12 and DiIC16) co-localized with transferrin in basolateral SE and in the SAC/ARC. By kinetic comparison of hepatic transport of transferrin and labelled HDL (high-density lipoprotein), it is shown that transport of transferrin from SE to the SAC/ARC follows a default pathway together with HDL. Kinetic modelling of fluorescence data provides an identical half-time for SE-to-SAC/ARC transport of transferrin and fluorescent HDL (t(1/2)=4.2 min). Fluorescent transferrin was found to recycle with a half-time of t(1/2)=12.9 min from the SAC/ARC to the basolateral cell surface of HepG2 cells. In contrast with HDL, targeting of labelled transferrin from the SAC/ARC to the apical biliary canaliculus was negligible. The results indicate that transport from basolateral hepatic SE to the SAC/ARC represents a bulk flow process and that polarized sorting occurs mainly at the level of the SAC/ARC.
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Affiliation(s)
- Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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114
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Bai Y, Shen WC. Improving the Oral Efficacy of Recombinant Granulocyte Colony-Stimulating Factor and Transferrin Fusion Protein by Spacer Optimization. Pharm Res 2006; 23:2116-21. [PMID: 16952003 DOI: 10.1007/s11095-006-9059-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2006] [Accepted: 05/08/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE To improve the oral efficacy of the recombinant fusion protein containing granulocyte colony-stimulating factor (G-CSF) and transferrin (Tf) by inserting a linker between the two protein domains. MATERIALS AND METHODS Oligonucleotides encoding flexible and helix-forming peptides were inserted to the recombinant plasmids. The fusion protein without linker insertion was used for comparison. The G-CSF cell-proliferation and Tf receptor-binding activities of the fusion proteins were tested in NFS-60 cells and Caco-2 cells, respectively, and in vivo myelopoietic assay with both subcutaneous and oral administration was performed in BDF1 mice. RESULTS All fusion proteins produced from transfected HEK293 cells were positive in Western-blotting assay with anti-G-CSF and anti-Tf antibodies. Among them, the fusion protein with a long helical (H4-2) linker showed the highest activity in NFS-60 cell proliferation assay, with an EC50 about ten-fold lower than that of the non-linker fusion protein. The fusion protein with H4-2 linker also showed a significantly higher myelopoietic effect when administered either subcutaneously or orally in BDF1 mice. CONCLUSION The insertion of a linker peptide, such as the helix linker H4-2, between G-CSF and Tf domains in the recombinant fusion protein can improve significantly both in vitro and in vivo myelopoietic activity over the non-linker fusion protein.
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Affiliation(s)
- Yun Bai
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA
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115
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Bur M, Huwer H, Lehr CM, Hagen N, Guldbrandt M, Kim KJ, Ehrhardt C. Assessment of transport rates of proteins and peptides across primary human alveolar epithelial cell monolayers. Eur J Pharm Sci 2006; 28:196-203. [PMID: 16533597 DOI: 10.1016/j.ejps.2006.02.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 01/30/2006] [Accepted: 02/04/2006] [Indexed: 11/21/2022]
Abstract
In this study, we investigated bi-directional fluxes (i.e., in absorptive and secretive directions) of human serum proteins [albumin (HSA), transferrin (TF), and immunoglobulin G (IgG)] and peptides/proteins of potential therapeutic relevance [insulin (INS), glucagon-like peptide-1 (GLP-1), growth hormone (GH), and parathyroid hormone (PTH)] across tight monolayers of human alveolar epithelial cells (hAEpC) in primary culture. Apparent permeability coefficients (P(app); x10(-7)cm/s, mean+/-S.D.) for GLP-1 (6.13+/-0.87 (absorptive) versus 1.91+/-0.51 (secretive)), HSA (2.45+/-1.02 versus 0.21+/-0.31), TF (0.88+/-0.15 versus 0.30+/-0.03), and IgG (0.36+/-0.22 versus 0.15+/-0.16) were all strongly direction-dependent, i.e., net absorptive, while PTH (2.20+/-0.30 versus 1.80+/-0.77), GH (8.33+/-1.24 versus 9.02+/-3.43), and INS (0.77+/-0.15 versus 0.72+/-0.36) showed no directionality. Trichloroacetic acid precipitation analysis of tested molecules collected from donor and receiver fluids exhibited very little degradation. This is the first study on permeability data for a range of peptides and proteins across an in vitro model of the human alveolar epithelial barrier. These data indicate that there is no apparent size-dependent transport conforming to passive restricted diffusion for the tested substances across human alveolar barrier, in part confirming net absorptive transcytosis. The obtained data differ significantly from previously published reports utilising monolayers from different species. It can be concluded that the use of homologous tissue should be preferred to avoid species differences.
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Affiliation(s)
- Michael Bur
- Saarland University, Biopharmaceutics and Pharmaceutical Technology, 66123 Saarbrücken, Germany
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116
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Abstract
Nonviral vectors continue to be attractive alternatives to viruses due to their low toxicity and immunogenicity, lack of pathogenicity, and ease of pharmacologic production. However, nonviral vectors also continue to suffer from relatively low levels of gene transfer compared to viruses, thus the drive to improve these vectors continues. Many studies on vector-cell interactions have reported that nonviral vectors bind and enter cells efficiently, but yield low gene expression, thus directing our attention to the intracellular trafficking of these vectors to understand where the obstacles occur. Here, we will review nonviral vector trafficking pathways, which will be considered here as the steps from cell binding to nuclear delivery. Studies on the intracellular trafficking of nonviral vectors has given us valuable insights into the barriers these vectors must overcome to mediate efficient gene transfer. Importantly, we will highlight the different approaches used by researchers to overcome certain trafficking barriers to gene transfer, many of which incorporate components from biological systems that have naturally evolved the capacity to overcome such obstacles. The tools used to study trafficking pathways will also be discussed.
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Affiliation(s)
- L K Medina-Kauwe
- Gene Therapeutics Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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117
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Luo H, Nakatsu F, Furuno A, Kato H, Yamamoto A, Ohno H. Visualization of the post-Golgi trafficking of multiphoton photoactivated transferrin receptors. Cell Struct Funct 2006; 31:63-75. [PMID: 17072087 DOI: 10.1247/csf.31.63] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Newly synthesized membrane proteins are sorted in the trans-Golgi network (TGN) on the basis of sorting signals carried in their cytoplasmic domains and delivered to their final destinations in the secretory and endocytic pathways. Although previous studies have suggested the involvement of early endosomes in the biosynthetic pathway of transmembrane proteins, the precise trafficking routes followed by the newly synthesized plasma membrane proteins, such as transferrin receptors (TfRs), after exit from the TGN remain unclear. In this report, first, we demonstrated the advantages of photoactivating PA-GFP, a variant of the Aequorea victoria green fluorescent protein (GFP), with multiphoton laser light rather than single-photon laser light, in terms of photoactivation efficiency and spatial resolution. We then applied the multiphoton photoactivation technique to selectively photoactivate the TfR tagged with PA-GFP (PA-GFP-TfR) at the TGN, and monitored the movement of the photoactivated PA-GFP-TfR in live cells. We observed that the PA-GFP-TfR photoactivated at the TGN are transported to the Tfn(+)EEA1(+) endosomal compartments after exiting the TGN. These data support the notion that early endosomes can serve as a sorting station for not only internalized plasma membrane proteins in the endocytic pathway but also newly synthesized membrane proteins in the post-Golgi secretory pathway.
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Affiliation(s)
- Hong Luo
- Laboratory for Epithelial Immunobiology, Research Center for Allergy and Immunology, RIKEN
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118
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Steimer A, Haltner E, Lehr CM. Cell culture models of the respiratory tract relevant to pulmonary drug delivery. ACTA ACUST UNITED AC 2005; 18:137-82. [PMID: 15966771 DOI: 10.1089/jam.2005.18.137] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The respiratory tract holds promise as an alternative site of drug delivery due to fast absorption and rapid onset of drug action, with avoidance of hepatic and intestinal first-pass metabolism as an additional benefit compared to oral drug delivery. At present, the pharmaceutical industry increasingly relies on appropriate in vitro models for the faster evaluation of drug absorption and metabolism as an alternative to animal testing. This article reviews the various existing cell culture systems that may be applied as in vitro models of the human air-blood barrier, for instance, in order to enable the screening of large numbers of new drug candidates at low cost with high reliability and within a short time span. Apart from such screening, cell culture-based in vitro systems may also contribute to improve our understanding of the mechanisms of drug transport across such epithelial tissues, and the mechanisms of action how advanced drug carriers, such as nanoparticles or liposomes, can help to overcome these barriers. After all, the increasing use and acceptance of such in vitro models may lead to a significant acceleration of the drug development process by facilitating the progress into clinical studies and product registration.
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Affiliation(s)
- A Steimer
- Across Barriers GmbH, Department R&D Cell & Tissue Based Systems, Science Park Saar, Saarbrücken, Germany
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119
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Anabousi S, Laue M, Lehr CM, Bakowsky U, Ehrhardt C. Assessing transferrin modification of liposomes by atomic force microscopy and transmission electron microscopy. Eur J Pharm Biopharm 2005; 60:295-303. [PMID: 15939240 DOI: 10.1016/j.ejpb.2004.12.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 12/22/2004] [Accepted: 12/22/2004] [Indexed: 11/25/2022]
Abstract
Site-specific delivery of drugs and therapeutics can significantly reduce drug toxicity and increase the therapeutic effect. Transferrin (Tf) is one suitable ligand to be conjugated to drug delivery systems to achieve site-specific targeting, due to its specific binding to transferrin receptors (TfR), expressed on several cell types of therapeutic interest. TfRs have been reported to be highly expressed on the surfaces of tumour cells and the well-characterised and efficient mechanism of internalisation of Tf has been exploited for the delivery of anticancer drugs, proteins, and therapeutic genes into primarily proliferating malignant cells. Liposomes are effective vehicles for drugs, genes and vaccines and can be easily modified with proteins, antibodies, and other appropriate ligands, resulting in attractive formulations for targeted drug delivery. In this study, we used atomic force microscopy (AFM) and transmission electron microscopy (TEM) to confirm the conjugation of Tf to liposomes by three different coupling methods. In addition, the conventional assays for quantification of protein amount (BCA) and phospholipid content (according to Steward) were performed. AFM and TEM were able to display Tf-molecules on the liposomal surfaces and can be routinely used to obtain additional visual information on the protein-drug carrier conjugation in a fast and reliable manner.
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Affiliation(s)
- Samah Anabousi
- Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
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120
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Sahoo SK, Labhasetwar V. Enhanced Antiproliferative Activity of Transferrin-Conjugated Paclitaxel-Loaded Nanoparticles Is Mediated via Sustained Intracellular Drug Retention. Mol Pharm 2005; 2:373-83. [PMID: 16196490 DOI: 10.1021/mp050032z] [Citation(s) in RCA: 270] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We studied the molecular mechanism of greater efficacy of paclitaxel-loaded nanoparticles (Tx-NPs) following conjugation to transferrin (Tf) ligand in breast cancer cell line. NPs were formulated using biodegradable polymer, poly(lactic-co-glycolide) (PLGA), with encapsulated Tx and conjugated to Tf ligand via an epoxy linker. Tf-conjugated NPs demonstrated greater and sustained antiproliferative activity of the drug in dose- and time-dependent studies compared to that with drug in solution or unconjugated NPs in MCF-7 and MCF-7/Adr cells. The mechanism of greater antiproliferative activity of the drug with conjugated NPs was determined to be due to their greater cellular uptake and reduced exocytosis compared to that of unconjugated NPs, thus leading to higher and sustained intracellular drug levels. The increase in antiproliferative activity of the drug with incubation time in MCF-7/Adr cells with Tf-conjugated NPs suggests that the drug resistance can be overcome by sustaining intracellular drug retention. The intracellular disposition characteristics of Tf-conjugated NPs following their cellular uptake via Tf receptors could have been different from that of unconjugated NPs via nonspecific endocytic pathway, thus influencing the NP uptake, their intracellular retention, and hence the therapeutic efficacy of the encapsulated drug.
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Affiliation(s)
- Sanjeeb K Sahoo
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025, USA
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121
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Bai Y, Ann DK, Shen WC. Recombinant granulocyte colony-stimulating factor-transferrin fusion protein as an oral myelopoietic agent. Proc Natl Acad Sci U S A 2005; 102:7292-6. [PMID: 15870205 PMCID: PMC1129103 DOI: 10.1073/pnas.0500062102] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An expression construct harboring granulocyte colony-stimulating factor (G-CSF)-transferrin (Tf) fusion protein (G-CSF-Tf) was engineered by fusing human cDNAs encoding G-CSF and Tf to explore the feasibility of using Tf as a carrier moiety for oral delivery of therapeutic proteins. The recombinant protein, G-CSF-Tf, was harvested from protein-free, conditioned medium of transfected HEK293 cells. The in vitro studies demonstrated that the purified G-CSF-Tf fusion protein possesses the activity of both Tf receptor (TfR) binding in Caco-2 cells and G-CSF-dependent stimulation of NFS-60 cell proliferation. Subcutaneous administration of G-CSF-Tf fusion protein to BDF1 mice demonstrated a pharmacological effect comparable to the commercial G-CSF on the increase of absolute neutrophil counts (ANC). However, the fusion protein elicited a significant increase in ANC upon oral administration to BDF1 mice, whereas G-CSF had no effect. This study also showed that orally administered G-CSF-Tf elicits a sustained myelopoietic effect up to 3 days, whereas the s.c. administered G-CSF or G-CSF-Tf lasts only 1 day. Furthermore, coadministration of free Tf abolished the increase of ANC by orally delivered G-CSF-Tf, suggesting that the recombinant protein is absorbed via a TfR-mediated process in the gastrointestinal tract. Taken together, we conclude that the Tf-based recombinant fusion protein technology represents a promising approach for future development of orally effective peptide and protein drugs.
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Affiliation(s)
- Yun Bai
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
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122
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Yang PH, Sun X, Chiu JF, Sun H, He QY. Transferrin-Mediated Gold Nanoparticle Cellular Uptake. Bioconjug Chem 2005; 16:494-6. [PMID: 15898713 DOI: 10.1021/bc049775d] [Citation(s) in RCA: 251] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Targeted drug delivery is an important research area in specific therapy. Transferrin-conjugated nanoparticles are an attractive formulation as a vehicle for specific cellular uptake and targeted drug delivery. In this report, atomic force microscopy imaging was used to visualize the process of cellular uptake of transferrin-coupled gold nanoparticles on the surfaces of live cells for the first time. High-resolution images were captured, showing the endocytosis of transferrin-conjugated nanoparticles taking place during the process of internalization. This specific transferrin-mediated nanoparticle uptake was validated by confocal scanning imaging and transferrin competition experiments.
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Affiliation(s)
- Pei-Hui Yang
- Department of Chemistry and Open Laboratory of Chemical Biology, University of Hong Kong, Hong Kong
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123
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Abstract
Colloidal quantum dots are semiconductor nanocrystals well dispersed in a solvent. The optical properties of quantum dots, in particular the wavelength of their fluorescence, depend strongly on their size. Because of their reduced tendency to photobleach, colloidal quantum dots are interesting fluorescence probes for all types of labelling studies. In this review we will give an overview on how quantum dots have been used so far in cell biology. In particular we will discuss the biologically relevant properties of quantum dots and focus on four topics: labelling of cellular structures and receptors with quantum dots, incorporation of quantum dots by living cells, tracking the path and the fate of individual cells using quantum dot labels, and quantum dots as contrast agents.
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Affiliation(s)
- Wolfgang J Parak
- Center for Nanoscience, Ludwig Maximilians Universität München, Amalienstrasse 54, 80799 München, Germany
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124
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Campos SK, Parrott MB, Barry MA. Avidin-based targeting and purification of a protein IX-modified, metabolically biotinylated adenoviral vector. Mol Ther 2005; 9:942-54. [PMID: 15194061 PMCID: PMC4308313 DOI: 10.1016/j.ymthe.2004.03.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Accepted: 03/07/2004] [Indexed: 10/26/2022] Open
Abstract
While genetic modification of adenoviral vectors can produce vectors with modified tropism, incorporation of targeting peptides/proteins into the structural context of the virion can also result in destruction of ligand targeting or virion integrity. To combat this problem, we have developed a versatile targeting system using metabolically biotinylated adenoviral vectors bearing biotinylated fiber proteins. These vectors have been demonstrated to be useful as a platform for avidin-based ligand screening and vector targeting by conjugating biotinylated ligands to the virus using high-affinity tetrameric avidin (K(d) = 10(-15) M). The biotinylated vector could also be purified by biotin-reversible binding on monomeric avidin (K(d) = 10(-7) M). In this report, a second metabolically biotinylated adenovirus vector, Ad-IX-BAP, has been engineered by fusing a biotin acceptor peptide (BAP) to the C-terminus of the adenovirus pIX protein. This biotinylated vector displays twice as many biotins and was markedly superior for single-step affinity purification on monomeric avidin resin. However, unlike the fiber-biotinylated vector, Ad-IX-BAP failed to retarget to cells with biotinylated antibodies including anti-CD71 against the transferrin receptor. In contrast, Ad-IX-BAP was retargeted if transferrin, the cognate ligand for CD71, was used as a ligand rather than the anti-CD71. This work demonstrates the utility of metabolic biotinylation as a molecular screening tool to assess the utility of different viral capsid proteins for ligand display and the biology and compatibility of different ligands and receptors for vector targeting applications. These results also demonstrate the utility of the pIX-biotinylated vector as a platform for gentle single-step affinity purification of adenoviral vectors.
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Affiliation(s)
- Samuel K. Campos
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - M. Brandon Parrott
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael A. Barry
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
- To whom correspondence and reprint requests should be addressed at One Baylor Plaza, BCM505, Houston, TX 77030. Fax: +(713) 798-1481.
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125
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Sahoo SK, Ma W, Labhasetwar V. Efficacy of transferrin-conjugated paclitaxel-loaded nanoparticles in a murine model of prostate cancer. Int J Cancer 2004; 112:335-40. [PMID: 15352049 DOI: 10.1002/ijc.20405] [Citation(s) in RCA: 253] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Chemotherapy remains the preferred choice of treatment for prostate cancer but modest drug response and significant toxicity by conventional methods of administration limit their efficacy. In our study, we determined the efficacy of paclitaxel (Tx)-loaded biodegradable nanoparticles (NPs) on tumor inhibition. We hypothesized that NPs following conjugation to transferrin (Tf) ligand (NPs-Tf) would enhance the therapeutic efficacy of the encapsulated drug. The antiproliferative activity of NPs was determined in human prostate cancer cell line (PC3) and their effect on tumor inhibition in a murine model of prostate cancer. NPs (approximately 220 nm in diameter, 5.4% w/w drug loading) under in vitro conditions exhibited sustained release of the encapsulated drug (60% release in 60 days). The IC50 (concentration of drug for 50% inhibition of cell growth) of the drug with Tf-conjugated NPs (Tx-NPs-Tf) was about 5-fold lower than that with unconjugated NPs (Tx-NPs) or drug in solution. Animals that received a single-dose intratumoral injection of Tx-NPs-Tf (Tx dose= 4 mg/kg) demonstrated complete tumor regression and greater survival rate than those that received either Tx-NPs or Tx-Cremophor EL formulation. In conclusion, sustained release NPs demonstrated greater antitumor activity following their conjugation to Tf ligand.
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Affiliation(s)
- Sanjeeb K Sahoo
- Department of Pharmaceutical Sciences, Nebraska Medical Center, Omaha, NE 68198-6025, USA
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