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Chemical modification of bradykinin-polymer conjugates for optimum delivery of nanomedicines to tumors. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2024; 57:102744. [PMID: 38460653 DOI: 10.1016/j.nano.2024.102744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 02/15/2024] [Accepted: 03/01/2024] [Indexed: 03/11/2024]
Abstract
We recently prepared pH-responsive HPMA copolymer conjugates of bradykinin (P-BK), which release BK in response to the acidic tumor microenvironment, and found that administration of P-BK increased the tumor accumulation and therapeutic efficacy of nanomedicine. Because the release of BK from P-BK determines its onset of action, P-BKs with different release rates were prepared, and their properties were evaluated. The release kinetics were significantly altered by substitution proximal to hydrazone bond, release constant of methyl-substituted P-BK (P-MeBK) was approximately 4- and 80-fold higher than that of cyclopropyl-substituted P-BK (P-CPBK) and phenyl-substituted P-BK (P-PhBK). None of the P-BKs were active, but the release of BK restored their BK-like activity. Pre-administration of the P-BKs increased the tumor accumulation of nanomedicine in C26 tumor-bearing mice by 2- and 1.4-fold for P-MeBK and P-PhBK at 3 and 6 h. Altogether, this study provides insights into the design of pH-responsive nanodrugs with the desired release properties to target acidic lesions such as cancer and inflammation.
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Preparation of enzymatically highly active pegylated-D-amino acid oxidase and its application to antitumor therapy. Curr Drug Deliv 2021; 18:1121-1129. [PMID: 33550973 DOI: 10.2174/1567201818666210125111256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/12/2020] [Accepted: 11/26/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND D-amino acid oxidase (DAO) is an H2O2-generating enzyme, and tumor growth suppression by selective delivery of porcine DAO in tumors via the cytotoxic action of H2O2 has been reported. DAO isolated from Fusarium spp. (fDAO) shows much higher enzyme activity than porcine DAO, although the application of fDAO for antitumor treatment has not yet been determined. OBJECTIVE The purpose of this study was to prepare enzymatically highly active pegylated-fDAO, and to determine whether it accumulates in tumors and exerts a potent antitumor effect in tumor-bearing mice. METHODS Polyethylene glycol (PEG; Mw. 2000) was conjugated to fDAO to form PEGylated fDAO (PEG-fDAO). PEGfDAO was intravenously administered into S180 tumor-bearing mice, and the body distribution and antitumor activity of PEG-fDAO was determined. RESULTS The enzyme activity of PEG-fDAO was 26.1 U/mg, which was comparable to that of fDAO. Intravenously administered PEG-fDAO accumulated in tumors with less distribution in normal tissue except in the plasma. Enzyme activity in the tumor was 60-120 mU/g-tissue over 7-20 h after i.v. injection of 0.1 mg of PEG-fDAO. To generate the H2O2 in the tumor tissue, PEG-fDAO was intravenously administered, and then, D-phenylalanine was intraperitoneally administered after a lag time. No remarkable tumor suppression effect was observed under conditions used in this study, compared to the non-treated group. CONCLUSION The results suggest that PEG-fDAO maintained high enzymatic activity after pegylation. Treatment with PEGfDAO conferred high enzyme activity on tumor tissue; 3-6 fold higher than that of previously reported pDAO; however, high enzyme activity in the plasma limited repeated treatment owing to lethal toxicity, which seemingly led to poor therapeutic outcome. Overall, the use of PEG-fDAO is promising for antitumor therapy, although the suppression of DAO activity in the plasma would also be required rather than only the increase in DAO activity in the tumor for an antitumor effect.
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Discovery of inner centromere protein-derived small peptides for cancer imaging and treatment targeting survivin. Cancer Sci 2020; 111:1357-1366. [PMID: 31991041 PMCID: PMC7156834 DOI: 10.1111/cas.14330] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/16/2020] [Accepted: 01/18/2020] [Indexed: 12/15/2022] Open
Abstract
Survivin belongs to the inhibitor of apoptosis protein family, which is consistently overexpressed in most cancer cells but rarely expressed in normal adult tissues. Therefore, the detection and inhibition of survivin are regarded as attractive strategies for cancer‐specific treatment. In this study, we designed and synthesized 7‐19 residues of inner centromere protein (INCENP)‐derived small peptides (INC peptides) as novel survivin‐targeting agents. The INC peptides showed binding affinity for the human survivin protein (Kd = 91.4‐255 nmol L−1); INC16‐22, which contains residues 16‐22 of INCENP, showed the highest affinity (91.4 nmol L−1). Confocal fluorescence imaging showed consistent colocalization of FITC‐INC16‐22 and survivin in cell lines. Nona‐arginine‐linked INC16‐22 (r9‐INC16‐22) rendered INC16‐22 cells penetrable and strongly inhibited cell growth of MIA PaCa‐2 cells (52% inhibition at 1.0 µmol L−1) and MDA‐MB‐231 cells (60% inhibition at 10 µmol L−1) as determined by MTT assays. The exposure of MIA PaCa‐2 cells to 40 µmol L−1 r9‐INC16‐22 apparently reduced the intracellular protein expression levels of survivin. However, cleaved caspase‐3 was significantly increased in cells treated with r9‐INC16‐22, even at 10 µmol L−1, compared to untreated cells. Flow cytometry revealed that r9‐INC16‐22 strongly induced apoptosis in MIA PaCa‐2 cells. These results indicate that the cytotoxic effects of r9‐INC16‐22 could be mediated mainly through the disruption of survivin‐dependent antiapoptotic functions and partly because of the direct degradation of the survivin protein. Our findings suggest that INC peptides can act as useful scaffolds for novel cancer imaging and anticancer agents.
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Development of Radioiodinated Benzofuran Derivatives for in Vivo Imaging of Prion Deposits in the Brain. ACS Infect Dis 2019; 5:2003-2013. [PMID: 30875466 DOI: 10.1021/acsinfecdis.8b00184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Prion diseases are fatal neurodegenerative disorders associated with the deposition of abnormal prion protein aggregates (PrPSc) in the brain tissue. Here, we report the development of 125I-labeled iodobenzofuran (IBF) derivatives as single photon emission computed tomography (SPECT) imaging probes to detect cerebral PrPSc deposits. We synthesized and radioiodinated several 5-IBF and 6-IBF derivatives. The IBF derivatives were evaluated as prion imaging probes using recombinant mouse prion protein (rMoPrP) aggregates and brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. Although all the IBF derivatives were strongly adsorbed on the rMoPrP aggregates, [125I]5-IBF-NHMe displayed the highest adsorption rate and potent binding affinity with an equilibrium dissociation constant (Kd) of 12.3 nM. Fluorescence imaging using IBF-NHMe showed clear signals of the PrPSc-positive amyloid deposits in the mBSE-infected mouse brains. Biodistribution studies in normal mice demonstrated slow uptake and clearance from the brain of 125I-IBF derivatives. Among the derivatives, [125I]6-IBF-NH2 showed the highest peak brain uptake [2.59% injected dose (ID)/g at 10 min] and good clearance (0.51% ID/g at 180 min). Although the brain distribution of IBF derivatives should still be optimized for in vivo imaging, these compounds showed prospective binding properties to PrPSc. Further chemical modification of these IBF derivatives may contribute to the discovery of clinically applicable prion imaging probes.
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Abstract
As an essential micronutrient, selenium deficiency is a leading cause of cardiovascular diseases. The heart is continuously beating to deliver blood to the entire body, and this requires a high amount of energy. An adult heart normally obtains 50-70% of its adenosine 5'-triphosphate from fatty acid β-oxidation. An increase in fatty acid oxidation activity induces the generation of larger amounts of by-products (reactive oxygen species, ROS) from mitochondrial oxidative phosphorylation. Selenium-dependent glutathione peroxidases play a critical role in the removal of these ROS, especially organic hydroperoxides, from the heart. The definitive transport and/or detailed metabolic pathways from the selenium-source compounds to the selenoproteins in the heart still remain unclear. We explored the selenium-binding proteins in a rat cardiac cell lysate using its reactive metabolic intermediate, selenotrisulfide (STS), and MALDI TOF-mass spectrometry. Several proteins with a free cysteine (Cys) thiol were found to be reactive with STS through a thiol-exchange reaction. The most distinctive Cys-containing protein in the cardiac cell lysate was identified as myoglobin (Mb) from a rat protein database search and tryptic fragmentation experiments. When separately examined in selenium adequate rats, selenium-binding to the cardiac Mb was verified using selenium-specific fluorometry. Cardiac Mb is thought to participate in the selenium metabolic pathway in the heart.
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Superior Penetration and Cytotoxicity of HPMA Copolymer Conjugates of Pirarubicin in Tumor Cell Spheroid. Mol Pharm 2019; 16:3452-3459. [PMID: 31294568 DOI: 10.1021/acs.molpharmaceut.9b00248] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
N-(2-Hydroxypropyl)methacrylamide copolymer conjugates of pirarubicin (THP), P-THP, accumulates selectively in solid tumor tissue by the enhanced permeability and retention (EPR) effect. Despite of high accumulation in solid tumors, some macromolecular antitumor agents show poor therapeutic outcome because of poor tissue diffusion into the tumor as well as obstructed tumor blood flow. Here, we confirmed that cellular uptake of P-THP was 25 times less than that of free THP at 1-4 h incubation time in vitro. The passage of P-THP through the confluent tight-monolayer cells junction was 12 times higher than free THP, and P-THP penetrated deeper into the tumor cell spheroid (1.3-1.7-fold) than free THP in 4 h. In addition, P-THP showed cytotoxicity comparable to that of free THP to tumor-cells in spheroid form, despite of 7 times lower cytotoxicity of P-THP to the monolayer cells to that of free THP in vitro. These results indicate that P-THP administration can exhibit deeper diffusion into the tumor cell spheroid than free THP. As a consequence, P-THP exhibits more efficient antitumor activity than free THP in vivo, which is also supported by better pharmacokinetics and tumor accumulation of P-THP than free THP.
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In vitro assessment of bioavailability of selenium from a processed Japanese anchovy, Niboshi. Food Chem 2018; 269:436-441. [PMID: 30100457 DOI: 10.1016/j.foodchem.2018.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/24/2018] [Accepted: 07/03/2018] [Indexed: 11/29/2022]
Abstract
Niboshi is a commonly used foodstuff that is processed from Japanese anchovy (Engraulis japonicus) in Japanese cuisine. It was previously demonstrated that Niboshi and its water extract contained highly bioavailable selenium for selenium deficient mice. In this study, we assessed the selenium bioavailability from the extract of the Niboshi, using cultured cells. The activity of selenium-dependent glutathione peroxidase (GPx) of rat dorsal ganglion cells and human cervical carcinoma cells incubated with selenium from the Niboshi extract was over 2 times of that of the extract-free control cells and comparable to that of cells incubated with selenious acid of the same selenium concentration. These results suggest that selenium from the Niboshi extract was utilized for synthesis of the selenoprotein. Such in vitro selenium bioavailability was consistent with our previous results of in vivo assessment in mice.
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Synthesis and characterization of radioiodinated 3-phenethyl-2-indolinone derivatives for SPECT imaging of survivin in tumors. Bioorg Med Chem 2018; 26:3111-3116. [PMID: 29703424 DOI: 10.1016/j.bmc.2018.04.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/11/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022]
Abstract
Survivin, overexpressed in most cancers, is associated with poor prognosis and resistance to radiation therapy and chemotherapy. Herein, we report the synthesis of three 3-phenethyl-2-indolinone derivatives and their application as in vivo imaging agents for survivin. Of these, 3-(2-(benzo[d][1,3]dioxol-5-yl)-2-oxoethyl)-3-hydroxy-5- iodoindolin-2-one (IPI-1) showed the highest binding affinity (Kd = 68.3 nM) to recombinant human survivin, as determined by quartz crystal microbalance (QCM). In vitro studies demonstrated that the [125I]IPI-1 binding in survivin-positive MDA-MB-231 cells was significantly higher than that in survivin-negative MCF-10A cells. In addition, uptake of [125I]IPI-1 by MDA-MB-231 cells decreased in a dose-dependent manner in the presence of the high-affinity survivin ligand S12; this is indicative of specific binding of [125I]IPI-1 to cellular survivin protein in vitro. Biodistribution studies in MDA-MB-231 tumor-bearing mice demonstrated the moderate uptake of [125I]IPI-1 in the tumor tissue (1.37% ID/g) at 30 min that decreased to 0.32% ID/g at 180 min. Co-injection of S12 (2.5 mg/kg) slightly reduced tumor uptake and the tumor/muscle ratio of [125I]IPI-1. Although further structural modifications are necessary to improve pharmacokinetic properties, our results indicate that PI derivatives may be useful as tumor-imaging probes targeting survivin.
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Preparation and in Vitro Analysis of Human Serum Albumin Nanoparticles Loaded with Anthracycline Derivatives. Chem Pharm Bull (Tokyo) 2018; 66:382-390. [PMID: 29607904 DOI: 10.1248/cpb.c17-00838] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nanoparticles prepared using human serum albumin (HSA) have emerged as versatile carriers for improving the pharmacokinetic profile of drugs. The desolvation of HSA using ethanol followed by stabilization through crosslinking with glutaraldehyde is a common technique for preparing HSA nanoparticles, but our knowledge concerning the characteristics (or functions) of HSA nanoparticles and their efficiency when loaded with drugs is limited. To address this issue in more detail, we prepared anthracycline-loaded HSA nanoparticles. Doxorubicin-loaded HSA nanoparticles with a size similar to doxorubicin-unloaded particles could be prepared by desolvating at a higher pH (8-9), and the size (100-150 nm) was optimum for delivery to tumor tissues. Using this procedure, HSA nanoparticles were loaded with other anthracycline derivatives, and all showed cytotoxicity in cancer cells. However, the efficiency of drug loading and dissolution rate were different among them possibly due to the differences in the type of association of the drugs on nanoparticles (doxorubicin and daunorubicin; covalently bound to nanoparticles, pirarubicin; both covalently bound to and adsorbed on nanoparticles, aclarubicin; adsorbed on nanoparticles). Since the formulation of such drug-loaded HSA nanoparticles should be modified for efficient delivery to tumors, the findings reported herein provide the useful information for optimizing the formulation and the production process for the HSA nanoparticles using a desolvation technique.
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Selenoprotein L-inspired nano-vesicular peroxidase mimics based on amphiphilic diselenides. Colloids Surf B Biointerfaces 2017; 162:172-178. [PMID: 29190468 DOI: 10.1016/j.colsurfb.2017.11.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 10/26/2017] [Accepted: 11/25/2017] [Indexed: 12/17/2022]
Abstract
In this study, we developed selenoprotein L-inspired nano-vesicular peroxidase mimics based on amphiphilic diselenides. Selenocystine (SeCyst) was used as the starting material for the synthesis of four liposomal membrane-compatible diselenide derivatives (R-Se-Se-R') with two hydrophobic tails and a polar part. The diselenide derivatives were successfully incorporated into the phosphatidylcholine (PC)-based nano-vesicular scaffold. The results of the particle diameter and zeta-potential measurements suggested that the functional diselenide moiety was placed around the outer surface, not in the hydrophobic interior, of the liposomal membrane structures. The GPx-like catalytic activity of the diselenide/PC liposomes was determined by the conventional NADPH method using glutathione as the reducing substrate. For three peroxide substrates, i.e., hydrogen peroxide, organic tert-butyl hydroperoxide and cummen hydroperoxide, the cationic property-possessing diselenide derivatives in the PC-based liposomes resulted in a higher catalytic activity in comparison to electrically neutral and anionic derivatives. Overall, the diselenide derivatives at the surface of a liposomal colloidal scaffold could exert a GPx-like catalytic activity in physiological aqueous media.
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Abstract
Selenium is an essential trace element for humans and animals. Fish and shellfish are known to be rich in selenium and suppose to be an effective selenium source. In this study, we characterized the selenium species in the Shijimi clam (Corbicula japonica), which is a typical clam eaten in Japan. The Shijimi clam contains a relatively high concentration of selenium (3.5 µg-selenium/g-dry Shijimi). Approximately 30% of the total selenium in the Shijimi clam meat was extractable with water, while selenium in the Shijimi clam was hardly extracted with ethanol, chloroform and hexane. Based on an ultrafiltration study, the molecular mass of the major selenium species in the Shijimi water-extract was estimated to be less than 5000. Because amphoteric selenium species were contained in the Shijimi water-extract, which was indicated by ion-exchange chromatographic separation, an ion-pair reagent was utilized to extract the ionic selenium species into an organic solvent. A matrix assisted laser desorption ionization (MALDI) time of flight (TOF)-mass spectrometric analysis revealed the selenium isotopic pattern involving one selenium atom in a molecule with the 80Se molecular ion peak at m/z 534. This selenium species was mainly found in the visceral part of the Shijimi clam by imaging mass spectrometry.
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Development of a 68Ge/ 68Ga Generator System Using Polysaccharide Polymers and Its Application in PET Imaging of Tropical Infectious Diseases. ACS OMEGA 2017; 2:1400-1407. [PMID: 30023633 PMCID: PMC6044706 DOI: 10.1021/acsomega.7b00147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/31/2017] [Indexed: 06/08/2023]
Abstract
Gallium-68 (68Ga) is a positron emitter for clinical positron emission tomography (PET) applications that can be produced by a 68Ge/68Ga generator without cyclotron. However, commercially available 68Ge/68Ga generator systems require multiple steps for the preparation of 68Ga radiopharmaceuticals and are sometimes plagued by metallic impurities in the 68Ga eluent. We developed a 68Ge/68Ga generator system using polysaccharide-based adsorbents and direct application of the generator-eluted 68Ga-citrate to PET imaging of tropical infectious diseases. N-Methylglucamine (MG) as a 68Ge-adsorbing unit (Sepha-MGs) was introduced to a series of Sephadex G-10, G-15, G-25, G-50, and G-75. In the batch method, over 97% of the 68Ge in the solution was adsorbed onto the Sepha-MG series within 15 min. In particular, 68Ge was effectively adsorbed on the Sepha(15)-MG packed columns and 70-80% of the 68Ga was eluted by 1 mL of 0.1 M trisodium citrate with low 68Ge contamination (<0.001%). The chemical form of the generator-eluted 68Ga solution was identified as 68Ga-citrate. In PET studies, affected regions in mice infected with Leishmania and severe fever with thrombocytopenia syndrome virus were clearly visualized using the 68Ga-citrate. Sepha-MGs are useful adsorbents for 68Ge/68Ga generator systems with high 68Ga elution efficiency and minimal 68Ge breakthrough. These results indicated that eluted 68Ga-citrate can be directly used for PET imaging of infectious sites in mice. This novel generator system may be useful for straightforward PET imaging of infection in clinical practice.
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Development of radioiodinated acridine derivatives for in vivo imaging of prion deposits in the brain. Bioorg Med Chem 2016; 25:1085-1093. [PMID: 28041803 DOI: 10.1016/j.bmc.2016.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/30/2016] [Accepted: 12/16/2016] [Indexed: 01/04/2023]
Abstract
Prion diseases are caused by deposition of abnormal prion protein aggregates (PrPSc) in the central nervous system. This study aimed to develop in vivo imaging probes that can detect cerebral PrPSc deposits. We synthesized several quinacrine-based acridine (AC) derivatives with 2,9-substitution and radioiodinated them. The AC derivatives were evaluated as prion-imaging probes using recombinant mouse prion protein (rMoPrP) aggregates and brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. The distribution of these compounds in mice was also evaluated. The 2-methoxy derivative [125I]2 exhibited the highest binding affinity for rMoPrP aggregates with an equilibrium dissociation constant (Kd) value of 43.4nM. Fluorescence imaging with 2 showed clear signals at the thioflavin T (ThT)-positive amyloid deposits in the mBSE-infected mouse brain. Although a discrepancy was observed between the in vitro binding of AC derivatives to the aggregates and in vivo distribution of these compounds in the brain and we failed to identify prospective prion-imaging probes in this study, the AC derivatives may be considered a useful scaffold for the development of in vivo imaging probes. Further chemical modification of these AC derivatives may discover clinically applicable prion imaging probes.
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Pronounced Cellular Uptake of Pirarubicin versus That of Other Anthracyclines: Comparison of HPMA Copolymer Conjugates of Pirarubicin and Doxorubicin. Mol Pharm 2016; 13:4106-4115. [PMID: 27934482 DOI: 10.1021/acs.molpharmaceut.6b00697] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many conjugates of water-soluble polymers with biologically active molecules were developed during the last two decades. Although, therapeutic effects of these conjugates are affected by the properties of carriers, the properties of the attached drugs appear more important than the same carrier polymer in this case. Pirarubicin (THP), a tetrahydropyranyl derivative of doxorubicin (DOX), demonstrated more rapid cellular internalization and potent cytotoxicity than DOX. Here, we conjugated the THP or DOX to N-(2-hydroxypropyl)methacrylamide copolymer via a hydrazone bond. The polymeric prodrug conjugates, P-THP and P-DOX, respectively, had comparable hydrodynamic sizes and drug loading. Compared with P-DOX, P-THP showed approximately 10 times greater cellular uptake during a 240 min incubation and a cytotoxicity that was more than 10 times higher during a 72-h incubation. A marginal difference was seen in P-THP and P-DOX accumulation in the liver and kidney at 6 h after drug administration, but no significant difference occurred in the tumor drug concentration during 6-24 h after drug administration. Antitumor activity against xenograft human pancreatic tumor (SUIT2) in mice was greater for P-THP than for P-DOX. To sum up, the present study compared the biological behavior of two different drugs, each attached to an N-(2-hydroxypropyl)methacrylamide copolymer carrier, with regard to their uptake by tumor cells, body distribution, accumulation in tumors, cytotoxicity, and antitumor activity in vitro and in vivo. No differences in the tumor cell uptake of the polymer-drug conjugates, P-THP and P-DOX, were observed. In contrast, the intracellular uptake of free THP liberated from the P-THP was 25-30 times higher than that of DOX liberated from P-DOX. This finding indicates that proper selection of the carrier, and especially conjugated active pharmaceutical ingredient (API) are most critical for anticancer activity of the polymer-drug conjugates. THP, in this respect, was found to be a more preferable API for polymer conjugation than DOX. Hence the treatment based on enhanced permeability and retention (EPR) effect that targets more selectively to solid tumors can be best achieved with THP, although both polymer conjugates of DOX and THP exhibited the EPR effects and drug release profiles in acidic pH similarly.
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Synthesis of Nanovesicular Glutathione Peroxidase Mimics with a Selenenylsulfide-Bearing Lipid. ACS OMEGA 2016; 1:58-65. [PMID: 30023472 PMCID: PMC6044637 DOI: 10.1021/acsomega.6b00046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/22/2016] [Indexed: 06/08/2023]
Abstract
In this article, we describe the development of a nanosized-glutathione peroxidase (GPx) mimic based on liposomes of which the amphiphilic selenenylsulfide derivative (R-Se-S-R') was incorporated into a lipid membrane. A lipid membrane-compatible selenenylsulfide derivative, 1-oxo-headecyl-seleno-l-cysteine-methyl-Se-yl-S-l-penicillamine methyl ester (OHSeP), was synthesized. X-ray photoelectron spectroscopy revealed that the sulfur and selenium atoms of the OHSeP molecule formed a selenenylsulfide linkage. The use of OHSeP easily allowed the introduction of the seleno-l-cysteine (SeCys) moiety into the liposomal membranes by mixing with the phosphatidylcholines (PCs), which gave rise to the GPx-like catalytic activity because of the selenium atom in the SeCys moiety. The penicillamine moiety of the OHSeP molecule incorporated into the OHSeP/PC liposomes was thought to orient toward the outer water phase. The OHSeP/PC liposomes generated the GPx-like catalytic activity, which was ascribed to the SeCys moiety that was introduced into the PC-based liposomes. Consequently, the lipid/water interface of the liposomal membranes could possibly provide an effective colloidal platform for the development of water-soluble nanosized GPx mimics.
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Oligopeptides as an Oral Delivery System: I. Aggregation Characteristics and Drug Encapsulation. J BIOACT COMPAT POL 2016. [DOI: 10.1177/088391159701200203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A series of glutamic acid(E)-phenylalanine(F) oligopeptides were studied as potential oral drug delivery systems for protein and polysaccharide drugs. The aggregation behavior of the tri- and tetrapeptides (pEE(a)F, pEE(y)F, pEE(a)F(y)F) were characterized by light scattering and light microscopy. The tripeptides did not form aggregates up to 0.1 M at pH 2. On the other hand, the tetrapeptide pEE(a)F(y)F formed self-aggregates at relatively low concentrations (11.8 mM). This tetrapeptide also associated preferentially with several drug molecules, such as insulin and bovine serum albumin, below the concentration at which the aggregation occurred. The same concentration of unassociated pEE(a)F(y)F was necessary to achieve aggregation whether the pEE(a)F(y)F was associated with drugs or not. The pEE(a)F(y)F also formed unique spheres in the presence of protein drugs.
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Oligopeptides as an Oral Delivery System II. Effect of Amino Acid Sequences on Aggregation Behavior. J BIOACT COMPAT POL 2016. [DOI: 10.1177/088391159701200402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effect of amino acid sequences on the aggregation and the subsequent sphere formation behavior of tetrapeptides, pEE(a)X(y) involving glutamic acid (E), phenylalanine (F), tyrosine (Y), alanine (A), and leucine (L) were investigated by light scattering and light microscopy. At 0.1 M pEE(a)Y(y)Y and pEE(a)F(y)F showed similar pH and concentration-dependent aggregation behaviors. These tetrapeptides also showed similar aggregation profiles in the presence of macromolecular drugs. Only pEE(a)F(y)F produced discrete spheres in the presence of protein drugs. Neither pEE(a)A(y)A nor pEE(a)L(y)L gave aggregates even at 0.1 M at pH 2. Consequently, the amino acids terminal positions are important in the aggregation characteristics of the tetrapeptides.
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A Comprehensive Analysis of Selenium-Binding Proteins in the Brain Using Its Reactive Metabolite. Chem Pharm Bull (Tokyo) 2016; 64:52-8. [DOI: 10.1248/cpb.c15-00689] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Characterisation of radioiodinated flavonoid derivatives for SPECT imaging of cerebral prion deposits. Sci Rep 2015; 5:18440. [PMID: 26669576 PMCID: PMC4680881 DOI: 10.1038/srep18440] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/18/2015] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are fatal neurodegenerative diseases characterised by deposition of amyloid plaques containing abnormal prion protein aggregates (PrP(Sc)). This study aimed to evaluate the potential of radioiodinated flavonoid derivatives for single photon emission computed tomography (SPECT) imaging of PrP(Sc). In vitro binding assays using recombinant mouse PrP (rMoPrP) aggregates revealed that the 4-dimethylamino-substituted styrylchromone derivative (SC-NMe2) had higher in vitro binding affinity (Kd = 24.5 nM) and capacity (Bmax = 36.3 pmol/nmol protein) than three other flavonoid derivatives (flavone, chalcone, and aurone). Fluorescent imaging using brain sections from mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice demonstrated that SC-NMe2 clearly labelled PrP(Sc)-positive prion deposits in the mice brain. Two methoxy SC derivatives, SC-OMe and SC-(OMe)2, also showed high binding affinity for rMoPrP aggregates with Ki values of 20.8 and 26.6 nM, respectively. In vitro fluorescence and autoradiography experiments demonstrated high accumulation of [(125)I]SC-OMe and [(125)I]SC-(OMe)2 in prion deposit-rich regions of the mBSE-infected mouse brain. SPECT/computed tomography (CT) imaging and ex vivo autoradiography demonstrated that [(123)I]SC-OMe showed consistent brain distribution with the presence of PrP(Sc) deposits in the mBSE-infected mice brain. In conclusion, [(123)I]SC-OMe appears a promising SPECT radioligand for monitoring prion deposit levels in the living brain.
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Synthesis and evaluation of a radioiodinated 4,6-diaryl-3-cyano-2-pyridinone derivative as a survivin targeting SPECT probe for tumor imaging. Bioorg Med Chem Lett 2015; 26:999-1004. [PMID: 26733475 DOI: 10.1016/j.bmcl.2015.12.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/03/2015] [Accepted: 12/15/2015] [Indexed: 10/22/2022]
Abstract
Survivin is overexpressed in most of the cancerous tissues but not in terminally differentiated normal tissues, making it an attractive target for diagnosis and therapy of various types of cancers. In this study, we aimed to develop 4,6-diaryl-3-cyano-2-pyridinone (DCP) derivatives, as novel cancer imaging probes that target survivin. Chloro and iodo analogs of DCP (CDCP and IDCP, respectively) were successfully synthesized by using a previously unreported carbon monoxide-free procedure. IDCP exhibited a slightly higher binding affinity for recombinant human survivin (Kd=34 nM) than that of CDCP (Kd=44 nM). Fluorescence staining indicated that both CDCP and IDCP showed high signals in MDA-MB-231 cells with high levels of survivin expression. Significantly low fluorescent signals were observed in MCF-10A cells, which showed low levels of survivin expression. [(125)I]IDCP was synthesized for the application of IDCP to single photon emission computed tomography (SPECT) imaging. Quantitative in vitro binding of [(125)I]IDCP in cell cultures showed results consistent to those observed after fluorescent staining. In vivo biodistribution studies in tumor-bearing mice demonstrated that the tumor uptake of [(125)I]IDCP increased gradually with time and was 0.65% injected dose per gram (% ID/g) at 180 min. The maximum tumor/blood and tumor/muscle ratio at 60 min were 0.87 and 2.27, respectively, indicating inadequate [(125)I]IDCP accumulation in tumors necessary for in vivo imaging. Although further structural modifications are necessary to improve pharmacokinetic properties of IDCP, this study demonstrates the feasibility of using the DCP backbone as a scaffold for the development of survivin-targeting tumor imaging probes.
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An effective method for profiling the selenium-binding proteins using its reactive metabolic intermediate. J Biol Inorg Chem 2015; 20:781-9. [DOI: 10.1007/s00775-015-1265-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
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22
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A strontium-90 sequestrant for first-aid treatment of radiation emergency. Chem Pharm Bull (Tokyo) 2013; 60:1258-63. [PMID: 23036968 DOI: 10.1248/cpb.c12-00430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, hydrophilic porous polymer beads with phosphonic acid groups (PGMA-EGDMA-TTA-MP) were synthesized, and assessed as a radioactive strontium-90 sequestrant for the treatment of the radiation emergency. Strontium ions were rapidly absorbed into the blood from the gastrointestinal (GI) tract after oral administration to rats, and distributed to the target organ, i.e., bones. Over 40% of the administered strontium was absorbed into the blood, while the remainder was discharged in the feces within 48 h after the administration. When the PGMA-EGDMA-TTA-MP beads were administered to rats subsequent to the strontium solution, the strontium had accumulated less in the femur. Consequently, the oral administration of the PGMA-EGDMA-TTA-MP beads was effective in suppressing the absorption of strontium from the GI tract.
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Improved membrane fluidity of ionic polysaccharide bead-supported phospholipid bilayer membrane systems. Colloids Surf B Biointerfaces 2013; 107:90-6. [PMID: 23466547 DOI: 10.1016/j.colsurfb.2013.01.070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/24/2013] [Accepted: 01/28/2013] [Indexed: 11/24/2022]
Abstract
Supported phospholipid bilayer membranes on polysaccharide-based cationic polymer beads (cationic group: -[OCH2CH(OH)CH2]2N(+)(CH3)3·X(-), 45-165 μm in diameter) were prepared using small unilamellar vesicles from mixtures of phosphatidylserine (PS) and phosphatidylcholine (PC). Confocal fluorescence microscopic observations with a fluorescent membrane probe (N-4-nitrobenzo-2-oxa-1,3-diazole-phosphatidylethanolamine) revealed that the phospholipid molecules in the phospholipid-bead complexes were along the outer surface of the beads. The fluidity of the phospholipid bilayer membranes in the PS/PC-bead complexes was investigated by the fluorescence recovery after photobleaching (FRAP) technique. The lateral diffusion coefficients (D) for the PS/PC-bead complexes were lower than that for the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine giant unilamellar vesicles without solid supports. Such less fluid membranes in the complexes appeared to be due to the immobilization of the phospholipid bilayer membranes by electrostatic attractive forces between PS and the bead. The D values for the PS/PC-bead complexes were dependent on the phospholipid composition; the PS(100 mol%)/PC(0 mol%)-bead complex had the least fluid membranes among the PS/PC-bead complexes tested in this study. The phospholipid bilayer membranes formed on the polysaccharide-based cationic polymer beads were much more fluid than those on a polystyrene-based one. Furthermore, such fluid phospholipid bilayer membranes formed on the polysaccharide-based cationic polymer bead were maintained for 10 days, even though the complex sample was stood in plain buffer (pH 8.5) at ambient temperature.
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Synthesis and biological evaluation of radioiodinated quinacrine-based derivatives for SPECT imaging of Aβ plaques. Eur J Med Chem 2013; 60:469-78. [DOI: 10.1016/j.ejmech.2012.12.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/29/2012] [Accepted: 12/08/2012] [Indexed: 10/27/2022]
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Elevated amyloid-β plaque deposition in dietary selenium-deficient Tg2576 transgenic mice. Metallomics 2013; 5:479-83. [DOI: 10.1039/c3mt00035d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Synthesis and evaluation of 2-chloro N-[(S)-{(S)-1-[11 C]methylpiperidin-2-yl} (phenyl)methyl]3-trifluoromethyl-benzamide ([11 C]N-methyl-SSR504734) as a PET radioligand for glycine transporter 1. EJNMMI Res 2012; 2:37. [PMID: 22776065 PMCID: PMC3531252 DOI: 10.1186/2191-219x-2-37] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/01/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Dysfunction of the glycine transporter 1 (GlyT1) has been suggested to be involved in psychiatric disorders such as schizophrenia. GlyT1 inhibitors have therefore been considered to have antipsychotic therapeutic potential. Positron emission tomography (PET) imaging probes for GlyT1 are, consequently, expected to be useful for investigating the mechanism of such disease conditions and for measuring occupancy of GlyT1 inhibitors in vivo. The aim of this study was to assess the potential of 2-chloro N-[(S)-{(S)-1-[11 C]methylpiperidin-2-yl} (phenyl)methyl] 3-trifluoromethyl-benzamide ([11 C]N-methyl-SSR504734) as a PET imaging agent for GlyT1. METHODS [11 C]N-methyl-SSR504734 was synthesized by N-[11 C]methylation of SSR504734 via [11 C]CH3OTf. In vitro brain distribution of [11 C]N-methyl-SSR504734 was tested in whole-hemisphere autoradiography (ARG) on human brain slices. Initial PET studies were performed using a cynomolgus monkey at baseline and after pretreatment with 0.1 to 1.5 mg/kg of SSR504734. Then, PET studies using rhesus monkeys were performed with arterial blood sampling at baseline and after pretreatment with 1.5 to 4.5 mg/kg SSR504734. Distribution volumes (VT) were calculated with a two-tissue compartment model, and GlyT1 occupancy by SSR504734 was estimated using a Lassen plot approach. RESULTS [11 C]N-methyl-SSR504734 was successfully synthesized in moderate radiochemical yield and high specific radioactivity. In the ARG experiments, [11 C]N-methyl-SSR504734 showed specific binding in the white matter and pons. In the initial PET experiments in a cynomolgus monkey, [11 C]N-methyl-SSR504734 showed high brain uptake and consistent distribution with previously reported GlyT1 expression in vivo (thalamus, brainstem > cerebellum > cortical regions). However, the brain uptake increased after pretreatment with SSR504734. Further PET studies in rhesus monkeys showed a similar increase of brain uptake after pretreatment with SSR504734. However, the VT of [11 C]N-methyl-SSR504734 was found to decrease after pretreatment of SSR504734 in a dose-dependent manner. GlyT1 occupancy was calculated to be 45% and 73% at 1.5 and 4.5 mg/kg of SSR504734, respectively. CONCLUSIONS [11 C]N-methyl-SSR504734 is demonstrated to be a promising PET radioligand for GlyT1 in nonhuman primates. The present results warrant further PET studies in human subjects.
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A thiol-mediated active membrane transport of selenium by erythroid anion exchanger 1 protein. Dalton Trans 2012; 41:7340-9. [PMID: 22580993 DOI: 10.1039/c2dt30707c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we describe a thiol-mediated and energy-dependent membrane transport of selenium by erythroid anion exchanger 1 (AE1, also known as band 3 protein). The AE1 is the most abundant integral protein of red cell membranes and plays a critical role in the carbon dioxide transport system in which carbon dioxide is carried as bicarbonate in the plasma. This protein mediates the membrane transport of selenium, an essential antioxidant micronutrient, from red cells to the plasma in a manner that is distinct from the already known anion exchange mechanism. In this pathway, selenium bound to the cysteine 93 of the hemoglobin β chain (Hb-Cysβ93) is transported by the relay mechanism to the Cys317 of the amino-terminal cytoplasmic domain of the AE1 on the basis of the intrinsic interaction between the two proteins and is subsequently exported to the plasma via the Cys843 of the membrane-spanning domain. The selenium export did not occur in plain isotonic buffer solutions and required thiols, such as albumin, in the outer medium. Such a membrane transport mechanism would also participate in the export pathways of the nitric oxide vasodilator activity and other thiol-reactive substances bound to the Hb-Cysβ93 from red cells to the plasma and/or peripherals.
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Characterization of Selenium Species in Extract from Niboshi (a Processed Japanese Anchovy). Chem Pharm Bull (Tokyo) 2012; 60:348-53. [DOI: 10.1248/cpb.60.348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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A novel bifunctional chelating agent based on bis(hydroxamamide) for 99mTc labeling of polypeptides. J Labelled Comp Radiopharm 2011. [DOI: 10.1002/jlcr.1954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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30
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A dual fluorinated and iodinated radiotracer for PET and SPECT imaging of β-amyloid plaques in the brain. Bioorg Med Chem Lett 2011; 21:6519-22. [DOI: 10.1016/j.bmcl.2011.08.063] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/12/2011] [Accepted: 08/13/2011] [Indexed: 10/17/2022]
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31
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Synthesis and characterization of [125I]2-iodo N-[(S)-{(S)-1-methylpiperidin-2-yl}(phenyl)methyl]3-trifluoromethyl-benzamide as novel imaging probe for glycine transporter 1. Bioorg Med Chem 2011; 19:6245-53. [DOI: 10.1016/j.bmc.2011.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/12/2023]
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32
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Absorption and retention characteristics of selenium in dorsal root ganglion neurons. Metallomics 2011; 3:1019-26. [DOI: 10.1039/c1mt00111f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Thiol-targeted introduction of selenocysteine to polypeptides for synthesis of glutathione peroxidase mimics. Metallomics 2011; 3:702-9. [DOI: 10.1039/c1mt00001b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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35
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Diphenylpropynone derivatives as probes for imaging β-amyloid plaques in Alzheimer's brains. Bioorg Med Chem Lett 2010; 21:117-20. [PMID: 21145738 DOI: 10.1016/j.bmcl.2010.11.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 11/09/2010] [Accepted: 11/13/2010] [Indexed: 11/19/2022]
Abstract
A new series of diphenylpropynone (DPP) derivatives for use in vivo to image β-amyloid (Aβ) plaques in the brain of patients with Alzheimer's disease (AD) were synthesized and characterized. Binding experiments in vitro revealed high affinity for Aβ (1-42) aggregates at a K(i) value ranging from 6 to 326 nM. Furthermore, specific labeling of plaques was observed in sections of brain tissue from Tg2576 transgenic mice stained using one of the compounds, 1. In biodistribution experiments with normal mice, [(125)I]1 displayed moderate uptake (1.55%ID/g at 2 min) and clearance from the brain with time (0.76 ID/g at 60 min). Taken together, DPP can serve as a new molecular scaffold for developing novel Aβ imaging agents by introducing appropriate substituted groups.
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Novel Benzofurans with (99m)Tc Complexes as Probes for Imaging Cerebral β-Amyloid Plaques. ACS Med Chem Lett 2010; 1:443-7. [PMID: 24900230 PMCID: PMC4007700 DOI: 10.1021/ml100140d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 07/26/2010] [Indexed: 11/30/2022] Open
Abstract
Two novel benzofuran derivatives coupled with (99m)Tc complexes were tested as probes for imaging cerebral β-amyloid plaques using single photon emission tomography. Although both derivatives bound to Aβ(1-42) aggregates, (99m)Tc-BAT-BF showed higher affinity than (99m)Tc-MAMA-BF. In sections of brain tissue from an animal model of AD, (99m)Tc-BAT-BF clearly labeled β-amyloid plaques. In biodistribution experiments using normal mice, (99m)Tc-BAT-BF displayed high uptake soon after its injection and washed out from the brain rapidly, a highly desirable feature for an imaging agent. (99m)Tc-BAT-BF may be a potential probe for imaging β-amyloid plaques in Alzheimer's brains.
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One-step direct reconstitution of biomembranes onto cationic organic polymer bead supports. J Colloid Interface Sci 2010; 351:96-101. [PMID: 20705302 DOI: 10.1016/j.jcis.2010.07.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/13/2010] [Accepted: 07/13/2010] [Indexed: 11/29/2022]
Abstract
In this study, we addressed the straightforward reconstitution of red blood cell (RBC) membranes on the surface of cationic organic polymer beads. The RBC membrane-bead complex was obtained by the incubation of white, unsealed rat RBC ghost membranes with a nonporous quaternary ammonium-type anion-exchange polymer bead with a 350-550 microm diameter. Confocal microscopic observations using a fluorescence membrane probe revealed that the RBC membranes were reconstituted on the outer surface of the bead without any remarkable structural gaps in the membrane. The absence of activity of two peripheral enzymes that latently reside on the cytoplasmic face of the RBC membranes demonstrated that the orientation of the RBC membranes immobilized on the beads was asymmetric as well as that in the native state. The RBC membrane-polymer bead complex was incubated with a primary antibody that is directed against the amino-terminal extracellular domain of the integral protein glycophorin A (GPA). The resulting complex was further incubated with a fluorescent secondary antibody and then subjected to confocal microscopic observations. Fluorescence resulting in the binding of the secondary antibody was found on the surface of the complex, which indicates that the amino-terminal extracellular domain of GPA is exposed to the surface of the complex. In addition, the anion uptake function of the most abundant integral protein anion-exchanger 1 (AE1) immobilized on the polymer beads was inhibited by pretreatment with its specific inhibitor 4,4'-diisothiocyano-2,2'-stilbene disulfonate, as is observed for the intact RBCs. Based on all these results, the RBC membranes were thought to be reconstituted on the ionic polymer beads by our one-pot procedure while maintaining the orientation and functions of the membrane proteins to some extent.
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Synthesis and biological evaluation of radio-iodinated benzimidazoles as SPECT imaging agents for NR2B subtype of NMDA receptor. Bioorg Med Chem 2010; 18:7497-506. [DOI: 10.1016/j.bmc.2010.08.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/27/2010] [Accepted: 08/28/2010] [Indexed: 10/19/2022]
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Synthesis and evaluation of novel chalcone derivatives with (99m)Tc/Re complexes as potential probes for detection of β-amyloid plaques. ACS Chem Neurosci 2010; 1:598-607. [PMID: 22778849 PMCID: PMC3368688 DOI: 10.1021/cn100042d] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 06/25/2010] [Indexed: 12/11/2022] Open
Abstract
Four (99m)Tc-labeled chalcone derivatives and their corresponding rhenium analogues were tested as potential probes for imaging β-amyloid plaques. The chalcones showed higher affinity for Aβ(1-42) aggregates than did (99m)Tc complexes. In sections of brain tissue from an animal model of AD, the four Re chalcones intensely stained β-amyloid plaques. In biodistribution experiments using normal mice, (99m)Tc-BAT-chalcone ([(99m)Tc]17) displayed high uptake in the brain (1.48% ID/g) at 2 min postinjection. The radioactivity washed out from the brain rapidly (0.17% ID/g at 60 min), a highly desirable feature for an imaging agent. [(99m)Tc]17 may be a potential probe for imaging β-amyloid plaques in Alzheimer's brains.
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99mTc/Re complexes based on flavone and aurone as SPECT probes for imaging cerebral β-amyloid plaques. Bioorg Med Chem Lett 2010; 20:5743-8. [PMID: 20797860 DOI: 10.1016/j.bmcl.2010.08.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 07/28/2010] [Accepted: 08/02/2010] [Indexed: 11/25/2022]
Abstract
Two (99m)Tc/Re complexes based on flavone and aurone were tested as potential probes for imaging β-amyloid plaques using single photon emission computed tomography. Both (99m)Tc-labeled derivatives showed higher affinity for Aβ(1-42) aggregates than did (99m)Tc-BAT. In sections of brain tissue from an animal model of AD, the Re-flavone derivative 9 and Re-aurone derivative 19 intensely stained β-amyloid plaques. In biodistribution experiments using normal mice, (99m)Tc-labeled flavone and aurone displayed similar radioactivity pharmacokinetics. With additional modifications to improve their brain uptake, (99m)Tc complexes based on the flavone or aurone scaffold may serve as probes for imaging cerebral β-amyloid plaques.
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Synthesis and characterization of novel phenylindoles as potential probes for imaging of β-amyloid plaques in the brain. Bioorg Med Chem 2010; 18:4740-6. [PMID: 20605471 DOI: 10.1016/j.bmc.2010.05.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 05/01/2010] [Accepted: 05/04/2010] [Indexed: 11/25/2022]
Abstract
We synthesized a novel series of phenylindole (PI) derivatives and evaluated their biological activities as probes for imaging Aβ plaques in vivo. The affinity for Aβ plaques was assessed by an in vitro-binding assay using pre-formed synthetic Aβ aggregates. 2-phenyl-1H-indole (2-PI) derivatives showed high affinity for Aβ42 aggregates with K(i) values ranging from 4 to 32 nM. 2-PI derivatives clearly stained Aβ plaques in an animal model of AD. In biodistribution experiments using normal mice, 2-PI derivatives displayed sufficient uptake for imaging, ranging from 1.1% to 2.6% ID/g. Although additional modifications are necessary to improve uptake by and clearance from the brain, 2-PI derivatives may be useful as a backbone structure to develop novel Aβ imaging agents.
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Abstract
Spherically supported bilayer membranes on cationic polymer beads were prepared from naturally occurring phospholipids (phosphatidylcholine (PC) and phosphatidylserine (PS)). The amount of phospholipids bound to the cationic polymer beads from the liposomal suspensions of various lipid compositions increased with increases in anionic PS. Confocal fluorescence microscopic observations with a fluorescence membrane probe indicated that the phospholipid molecules in the phospholipid-bead complexes were along the surface of the beads. Negatively charged trypan blue dye was preferably bound to the phospholipid-free beads by electrostatic attractive interaction, but was excluded from the phospholipid-bead complexes due to the bilayer membrane structure formed on the beads. This method could provide a better mimetic of biological membranes in comparison to physically unstable conventional liposomes.
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Fluoro-pegylated chalcones as positron emission tomography probes for in vivo imaging of beta-amyloid plaques in Alzheimer's disease. J Med Chem 2009; 52:6394-401. [PMID: 19757822 DOI: 10.1021/jm901057p] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes the synthesis and biological evaluation of fluoro-pegylated (FPEG) chalcones for the imaging of beta-amyloid (Abeta) plaques in patients with Alzheimer's disease (AD). FPEG chalcone derivatives were prepared by the aldol condensation reaction. In binding experiments conducted in vitro using Abeta(1-42) aggregates, the FPEG chalcone derivatives having a dimethylamino group showed higher Ki values (20-50 nM) than those having a monomethylamino or a primary amine group. When the biodistribution of 11C-labeled FPEG chalcone derivatives having a dimethyamino group was examined in normal mice, all four derivatives were found to display sufficient uptake for imaging Abeta plaques in the brain. 18F-labeled 7c also showed good uptake by and clearance from the brain, although a slight difference between the 11C and 18F tracers was observed. When the labeling of Abeta plaques was carried out using brain sections of AD model mice and an AD patient, the FPEG chalcone derivative 7c intensely labeled Abeta plaques. Taken together, the results suggest 7c to be a useful candidate PET tracer for detecting Abeta plaques in the brain of patients with AD.
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Synthesis and biological evaluation of radioiodinated 2,5-diphenyl-1,3,4-oxadiazoles for detecting β-amyloid plaques in the brain. Bioorg Med Chem 2009; 17:6402-6. [DOI: 10.1016/j.bmc.2009.07.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/10/2009] [Accepted: 07/11/2009] [Indexed: 11/26/2022]
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Thiol-Dependent Membrane Transport of Selenium through an Integral Protein of the Red Blood Cell Membrane. Inorg Chem 2009; 48:7805-11. [DOI: 10.1021/ic900988j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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46
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Novel radioiodinated aurones as probes for SPECT imaging of beta-amyloid plaques in the brain. Bioconjug Chem 2009; 20:95-101. [PMID: 19072219 DOI: 10.1021/bc8003292] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a novel series of radioiodinated aurone derivatives as probes for imaging Abeta plaques in the brains of patients with Alzheimer's disease (AD) using single photon emission computed tomography (SPECT). In binding experiments in vitro, aurone derivatives showed very good affinity for Abeta aggregates (K(i) = 1.1 to 3.4 nM). No-carrier-added radioiodinated aurones were successfully prepared through an iododestannylation reaction from the corresponding tributyltin derivatives. In biodistribution experiments using normal mice, aurone derivatives displayed high brain uptake (1.7-4.5% ID/g at 2 min) and rapid clearance from the brain (0.1-0.4% ID/g at 30 min), especially [125I]15. Furthermore, a specific plaque labeling signal was observed in in vitro autoradiography of postmortem AD brain sections using [125I]15. [125I]15 may be a useful SPECT imaging agent for detecting Abeta plaques in the brain of AD.
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18F-labeled flavones for in vivo imaging of β-amyloid plaques in Alzheimer’s brains. Bioorg Med Chem 2009; 17:2069-76. [DOI: 10.1016/j.bmc.2009.01.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 01/06/2009] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
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Nanoparticulate Glutathione Peroxidase Mimics Based on Selenocystine−Pullulan Conjugates. Bioconjug Chem 2008; 19:1831-9. [DOI: 10.1021/bc800086z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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50
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Hemoglobin-mediated selenium export from red blood cells. J Biol Inorg Chem 2008; 13:471-9. [DOI: 10.1007/s00775-007-0335-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 12/09/2007] [Indexed: 11/29/2022]
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