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Sample records for dendrimer conjugated anti-her2

  1. HER2 specific delivery of methotrexate by dendrimer conjugated anti-HER2 mAb

    International Nuclear Information System (INIS)

    Shukla, Rameshwer; Thomas, Thommey P; Desai, Ankur M; Kotlyar, Alina; Park, Steve J; Baker, James R Jr

    2008-01-01

    Herceptin, a humanized monoclonal antibody that binds to human growth factor receptor-2 (HER2), was covalently attached to a fifth-generation (G5) polyamidoamine dendrimer containing the cytotoxic drug methotrexate. The specific binding and internalization of this conjugate labeled with FITC was clearly demonstrated in cell lines overexpressing HER2 by flow cytometry as well as confocal microscopic analysis. In addition, binding and uptake of antibody conjugated dendrimers was completely blocked by excess non-conjugated herceptin. The dendrimer conjugate was also shown to inhibit the dihydrofolate reductase with similar activity to methotrexate. Co-localization experiments with lysotracker red indicate that antibody conjugate, although internalized efficiently into cells, has an unusually long residence time in the lysosome. Somewhat lower cytotoxicity of the conjugate in comparison to free methotrexate was attributed to the slow release of methotrexate from the conjugate and its long retention in the lysosomal pocket

  2. Antibody-dendrimer conjugates: the number, not the size of the dendrimers, determines the immunoreactivity.

    Science.gov (United States)

    Wängler, C; Moldenhauer, G; Eisenhut, M; Haberkorn, U; Mier, W

    2008-04-01

    Radioimmunotherapy using antibodies with favorable tumor targeting properties and high binding affinity is increasingly applied in cancer therapy. The potential of this valuable cancer treatment modality could be further improved by increasing the specific activity of the labeled proteins. This can be done either by coupling a large number of chelators which leads to a decreased immunoreactivity or by conjugating a small number of multimeric chelators. In order to systematically investigate the influence of conjugations on immunoreactivity with respect to size and number of the conjugates, the anti-EGFR antibody hMAb425 was reacted with PAMAM dendrimers of different size containing up to 128 chelating agents per conjugation site. An improved dendrimer synthesis protocol was established to obtain compounds of high homogeneity suitable for the formation of defined protein conjugates. The quantitative derivatization of the PAMAM dendrimers with DOTA moieties and the characterization of the products by isotopic dilution titration using (111)In/(nat)In are shown. The DOTA-containing dendrimers were conjugated with high efficiency to hMAb425 by applying Sulfo-SMCC as cross-linking agent and a 10- to 25-fold excess of the thiol-containing dendrimers. The determination of the immunoreactivities of the antibody-dendrimer conjugates by FACS analysis revealed a median retained immunoreactivity of 62.3% for 1.7 derivatization sites per antibody molecule, 55.4% for 2.8, 27.9% for 5.3, and 17.1% for 10.0 derivatization sites per antibody but no significant differences in immunoreactivity for different dendrimer sizes. These results show that the dendrimer size does not influence the immunoreactivity of the derivatized antibody significantly over a wide molecular weight range, whereas the number of derivatization sites has a crucial effect.

  3. Photosensitizer and peptide-conjugated PAMAM dendrimer for targeted in vivo photodynamic therapy.

    Science.gov (United States)

    Narsireddy, Amreddy; Vijayashree, Kurra; Adimoolam, Mahesh G; Manorama, Sunkara V; Rao, Nalam M

    2015-01-01

    Challenges in photodynamic therapy (PDT) include development of efficient near infrared-sensitive photosensitizers (5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine [PS]) and targeted delivery of PS to the tumor tissue. In this study, a dual functional dendrimer was synthesized for targeted PDT. For targeting, a poly(amidoamine) dendrimer (G4) was conjugated with a PS and a nitrilotriacetic acid (NTA) group. A peptide specific to human epidermal growth factor 2 was expressed in Escherichia coli with a His-tag and was specifically bound to the NTA group on the dendrimer. Reaction conditions were optimized to result in dendrimers with PS and the NTA at a fractional occupancy of 50% and 15%, respectively. The dendrimers were characterized by nuclear magnetic resonance, matrix-assisted laser desorption/ionization, absorbance, and fluorescence spectroscopy. Using PS fluorescence, cell uptake of these particles was confirmed by confocal microscopy and fluorescence-activated cell sorting. PS-dendrimers are more efficient than free PS in PDT-mediated cell death assays in HER2 positive cells, SK-OV-3. Similar effects were absent in HER2 negative cell line, MCF-7. Compared to free PS, the PS-dendrimers have shown significant tumor suppression in a xenograft animal tumor model. Conjugation of a PS with dendrimers and with a targeting agent has enhanced photodynamic therapeutic effects of the PS.

  4. Photosensitizer and peptide-conjugated PAMAM dendrimer for targeted in vivo photodynamic therapy

    Directory of Open Access Journals (Sweden)

    Narsireddy A

    2015-11-01

    Full Text Available Amreddy Narsireddy,1 Kurra Vijayashree,2 Mahesh G Adimoolam,1 Sunkara V Manorama,1 Nalam M Rao21CSIR – Indian Institute of Chemical Technology, 2CSIR – Centre for Cellular and Molecular Biology, Hyderabad, IndiaAbstract: Challenges in photodynamic therapy (PDT include development of efficient near infrared-sensitive photosensitizers (5,10,15,20-tetrakis(4-hydroxyphenyl-21H,23H-porphine [PS] and targeted delivery of PS to the tumor tissue. In this study, a dual functional dendrimer was synthesized for targeted PDT. For targeting, a poly(amidoamine dendrimer (G4 was conjugated with a PS and a nitrilotriacetic acid (NTA group. A peptide specific to human epidermal growth factor 2 was expressed in Escherichia coli with a His-tag and was specifically bound to the NTA group on the dendrimer. Reaction conditions were optimized to result in dendrimers with PS and the NTA at a fractional occupancy of 50% and 15%, respectively. The dendrimers were characterized by nuclear magnetic resonance, matrix-assisted laser desorption/ionization, absorbance, and fluorescence spectroscopy. Using PS fluorescence, cell uptake of these particles was confirmed by confocal microscopy and fluorescence-activated cell sorting. PS-dendrimers are more efficient than free PS in PDT-mediated cell death assays in HER2 positive cells, SK-OV-3. Similar effects were absent in HER2 negative cell line, MCF-7. Compared to free PS, the PS-dendrimers have shown significant tumor suppression in a xenograft animal tumor model. Conjugation of a PS with dendrimers and with a targeting agent has enhanced photodynamic therapeutic effects of the PS.Keywords: photodynamic therapy, dendrimers, nanoparticle, targeted delivery, Affibody, xenograft animal model

  5. Dynamics simulation of a π-conjugated light-harvesting dendrimer II: phenylene-based dendrimer (phDG2)

    International Nuclear Information System (INIS)

    Kodama, Yasunobu; Ishii, Soh; Ohno, Kaoru

    2009-01-01

    We investigate the light-harvesting property of a π-conjugated dendrimer, phenylene-based dendrimer (phDG2), by carrying out a semi-classical Ehrenfest dynamics simulation based on the time-dependent density functional theory. Similar to our previous study of star-shaped stilbenoid phthalocyanine (SSS1Pc), phDG2 shows electron and hole transfer from the periphery to the core through a π-conjugated network when an electron is selectively excited in the periphery. The one-way electron and hole transfer occurs more easily in dendrimers with planar structure than in those with steric hindrance because π-conjugation is well maintained in the planar structure. The present results explain recent experiments by Akai et al (2005 J. Lumin. 112 449).

  6. Quantification and imaging of HER2 protein using nanocrystals conjugated with single-domain antibodies

    International Nuclear Information System (INIS)

    Glukhov, S; Berestovoy, M; Nabiev, I; Sukhanova, A; Chames, P; Baty, D

    2017-01-01

    This study dealt with quantification and imaging of human epidermal growth factor receptor 2 (HER2), an important prognostic marker for cancer diagnosis and treatment, using specific quantum-dot-based conjugates. Fluorescent inorganic nanocrystals or quantum dots (QDs) are extremely highly resistant to photobleaching and have a high emission quantum yield and a continuous range of emission spectra, from the ultraviolet to the infrared regions. Ultrasmall nanoprobes consisting of highly affine anti-HER2 single-domain antibodies (sdAbs or 'nanobodies') conjugated with QDs in a strictly oriented manner have been designed. QDs with a fluorescence peak maxima at wavelengths of 562 nm, 569 nm, 570 nm or in the near-infrared region were used. Here, we present our results of ISA quantification of HER2 protein, in situ imaging of HER2 protein on the surface of HER2-positive SK-BR-3 cells in immunohistochemical experiments, and counting of stained with anti-HER2 conjugates HER2-positive SK-BR-3 cells in their mixture with unstained cells of the same culture in flow cytometry experiments. The data demonstrate that the anti-HER2 QD–sdAb conjugates obtained are highly specific and sensitive and could be used in numerous applications for advanced integrated diagnosis. (paper)

  7. Quantification and imaging of HER2 protein using nanocrystals conjugated with single-domain antibodies

    Science.gov (United States)

    Glukhov, S.; Berestovoy, M.; Chames, P.; Baty, D.; Nabiev, I.; Sukhanova, A.

    2017-01-01

    This study dealt with quantification and imaging of human epidermal growth factor receptor 2 (HER2), an important prognostic marker for cancer diagnosis and treatment, using specific quantum-dot-based conjugates. Fluorescent inorganic nanocrystals or quantum dots (QDs) are extremely highly resistant to photobleaching and have a high emission quantum yield and a continuous range of emission spectra, from the ultraviolet to the infrared regions. Ultrasmall nanoprobes consisting of highly affine anti-HER2 single-domain antibodies (sdAbs or "nanobodies") conjugated with QDs in a strictly oriented manner have been designed. QDs with a fluorescence peak maxima at wavelengths of 562 nm, 569 nm, 570 nm or in the near-infrared region were used. Here, we present our results of ISA quantification of HER2 protein, in situ imaging of HER2 protein on the surface of HER2-positive SK-BR-3 cells in immunohistochemical experiments, and counting of stained with anti-HER2 conjugates HER2-positive SK-BR-3 cells in their mixture with unstained cells of the same culture in flow cytometry experiments. The data demonstrate that the anti-HER2 QD-sdAb conjugates obtained are highly specific and sensitive and could be used in numerous applications for advanced integrated diagnosis.

  8. DENDRIMER CONJUGATES FOR SELECTIVE OF PROTEIN AGGREGATES

    DEFF Research Database (Denmark)

    2004-01-01

    Dendrimer conjugates are presented, which are formed between a dendrimer and a protein solubilising substance. Such dendrimer conjugates are effective in the treatment of protein aggregate-related diseases (e.g. prion-related diseases). The protein solubilising substance and the dendrimer together...

  9. Targeting of follicle stimulating hormone peptide-conjugated dendrimers to ovarian cancer cells

    Science.gov (United States)

    Modi, Dimple A.; Sunoqrot, Suhair; Bugno, Jason; Lantvit, Daniel D.; Hong, Seungpyo; Burdette, Joanna E.

    2014-02-01

    Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side effects. To address these issues, we have designed poly(amidoamine) (PAMAM) dendrimers to selectively target the follicle stimulating hormone receptor (FSHR), which is overexpressed by tumorigenic ovarian cancer cells but not by immature primordial follicles and other non-tumorigenic cells. Fluorescein-labeled generation 5 (G5) PAMAM dendrimers were conjugated with the binding peptide domain of FSH (FSH33) that has a high affinity to FSHR. The targeted dendrimers exhibited high receptor selectivity to FSHR-expressing OVCAR-3 cells, resulting in significant uptake and downregulation of an anti-apoptotic protein survivin, while showing minimal interactions with SKOV-3 cells that do not express FSHR. The selectivity of the FSH33-targeted dendrimers was further validated in 3D organ cultures of normal mouse ovaries. Immunostaining of the conjugates revealed their selective binding and uptake by ovarian surface epithelium (OSE) cells that express FSHR, while sparing the immature primordial follicles. In addition, an in vivo study monitoring tissue accumulation following a single intraperitoneal (i.p.) injection of the conjugates showed significantly higher accumulation of FSH33-targeted dendrimers in the ovary and oviduct compared to the non-targeted conjugates. These proof-of-concept findings highlight the potential of these FSH33-targeted dendrimers to serve as a delivery platform for anti-ovarian cancer drugs, while reducing their systemic side effects by preventing nonspecific uptake by the primordial follicles.Ovarian cancer is the most lethal gynecological malignancy. Current treatment modalities include a combination of surgery and chemotherapy, which often lead to loss of fertility in premenopausal women and a myriad of systemic side

  10. In Vitro Evaluation of Third Generation PAMAM Dendrimer Conjugates

    Directory of Open Access Journals (Sweden)

    Mohammad Najlah

    2017-10-01

    Full Text Available The present study compares the use of high generation G3 and low generation G0 Polyamidoamine (PAMAM dendrimers as drug carriers of naproxen (NAP, a poorly water soluble drug. Naproxen was conjugated to G3 in different ratios and to G0 in a 1:1 ratio via a diethylene glycol linker. A lauroyl chain (L, a lipophilic permeability enhancer, was attached to G3 and G0 prodrugs. The G3 and G0 conjugates were more hydrophilic than naproxen as evaluated by the measurement of partitioning between 1-octanol and a phosphate buffer at pH 7.4 and pH 1.2. The unmodified surface PAMAM-NAP conjugates showed significant solubility enhancements of NAP at pH 1.2; however, with the number of NAP conjugated to G3, this was limited to 10 molecules. The lactate dehydrogenase (LDH assay indicated that the G3 dendrimer conjugates had a concentration dependent toxicity towards Caco-2 cells. Attaching naproxen to the surface of the dendrimer increased the IC50 of the resulting prodrugs towards Caco-2 cells. The lauroyl G3 conjugates showed the highest toxicity amongst the PAMAM dendrimer conjugates investigated and were significantly more toxic than the lauroyl-G0-naproxen conjugates. The permeability of naproxen across monolayers of Caco-2 cells was significantly increased by its conjugation to either G3 or G0 PAMAM dendrimers. Lauroyl-G0 conjugates displayed considerably lower cytotoxicity than G3 conjugates and may be preferable for use as a drug carrier for low soluble drugs such as naproxen.

  11. Targeted delivery of polyamidoamine-paclitaxel conjugate functionalized with anti-human epidermal growth factor receptor 2 trastuzumab

    Directory of Open Access Journals (Sweden)

    Ma P

    2015-03-01

    Full Text Available Pengkai Ma,1 Xuemei Zhang,1 Ling Ni,2 Jinming Li,2 Fengpu Zhang,1 Zheng Wang,1 Shengnan Lian,1 Kaoxiang Sun1 1School of Pharmacy, Yantai University, Yantai, Shandong Province, People’s Republic of China; 2State Key Laboratory of Long-acting and Targeting Drug Delivery System, Yantai, Shandong Province, People’s Republic of China Background: Antibody-dendrimer conjugates have the potential to improve the targeting and release of chemotherapeutic drugs at the tumor site while reducing adverse side effects caused by drug accumulation in healthy tissues. In this study, trastuzumab (TMAB, which binds to human epidermal growth factor receptor 2 (HER2, was used as a targeting agent in a TMAB-polyamidoamine (PAMAM conjugate carrying paclitaxel (PTX specifically to cells overexpressing HER2. Methods: TMAB was covalently linked to a PAMAM dendrimer via bifunctional polyethylene glycol (PEG. PTX was conjugated to PAMAM using succinic anhydride as a cross-linker, yielding TMAB-PEG-PAMAM-PTX. Dynamic light scattering and transmission electron microscopy were used to characterize the conjugates. The cellular uptake and in vivo biodistribution were studied by fluorescence microscopy, flow cytometry, and Carestream In Vivo FX, respectively. Results: Nuclear magnetic resonance spectroscopy demonstrated that PEG, PTX, fluorescein isothiocyanate, and cyanine7 were conjugated to PAMAM. Ultraviolet-visible spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that TMAB was conjugated to PEG-PAMAM. Dynamic light scattering and transmission electron microscopy measurements revealed that the different conjugates ranged in size between 10 and 35 nm and had a spherical shape. In vitro cellular uptake demonstrated that the TMAB-conjugated PAMAM was taken up by HER2-overexpressing BT474 cells more efficiently than MCF-7 cells that expressed lower levels of HER2. Co-localization experiments indicated that TMAB-conjugated PAMAM was

  12. Synthesis and Characterization of Anti-HER2 Antibody Conjugated CdSe/CdZnS Quantum Dots for Fluorescence Imaging of Breast Cancer Cells

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    Takashi Jin

    2009-11-01

    Full Text Available The early detection of HER2 (human epidermal growth factor receptor 2 status in breast cancer patients is very important for the effective implementation of anti-HER2 antibody therapy. Recently, HER2 detections using antibody conjugated quantum dots (QDs have attracted much attention. QDs are a new class of fluorescent materials that have superior properties such as high brightness, high resistance to photo-bleaching, and multi-colored emission by a single-light source excitation. In this study, we synthesized three types of anti-HER2 antibody conjugated QDs (HER2Ab-QDs using different coupling agents (EDC/sulfo-NHS, iminothiolane/sulfo-SMCC, and sulfo-SMCC. As water-soluble QDs for the conjugation of antibody, we used glutathione coated CdSe/CdZnS QDs (GSH-QDs with fluorescence quantum yields of 0.23~0.39 in aqueous solution. Dispersibility, hydrodynamic size, and apparent molecular weights of the GSH-QDs and HER2Ab-QDs were characterized by using dynamic light scattering, fluorescence correlation spectroscopy, atomic force microscope, and size-exclusion HPLC. Fluorescence imaging of HER2 overexpressing cells (KPL-4 human breast cancer cell line was performed by using HER2Ab-QDs as fluorescent probes. We found that the HER2Ab-QD prepared by using SMCC coupling with partially reduced antibody is a most effective probe for the detection of HER2 expression in KPL-4 cells. We have also studied the size dependency of HER2Ab-QDs (with green, orange, and red emission on the fluorescence image of KPL-4 cells.

  13. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner...... conjugates and their use in vaccination, production of antibodies, high throughput screening, diagnostic assays and libraries....

  14. Highly lipophilic pluronics-conjugated polyamidoamine dendrimer nanocarriers as potential delivery system for hydrophobic drugs

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thi Tram Chau [Institute of Research and Development, Duy Tan University, Da Nang City 550000 (Viet Nam); Department of Chemical Engineering, Industrial University of HCMC, HCMC 70000 (Viet Nam); Nguyen, Cuu Khoa, E-mail: nckhoavnn@yahoo.com [Department of Materials and Pharmaceutical Chemistry, Vietnam Academy of Science and Technology, HCMC 70000 (Viet Nam); Nguyen, Thi Hiep [Biomedical Engineering Department, International University, National Universities in HCMC, HCMC 70000 (Viet Nam); Tran, Ngoc Quyen, E-mail: tnquyen@iams.vast.vn [Institute of Research and Development, Duy Tan University, Da Nang City 550000 (Viet Nam); Department of Materials and Pharmaceutical Chemistry, Vietnam Academy of Science and Technology, HCMC 70000 (Viet Nam)

    2017-01-01

    In the study, four kinds of pluronics (P123, F68, F127 and F108) with varying hydrophilic-lipophilic balance (HLB) values were modified and conjugated on 4th generation of polyamidoamine dendrimer (PAMAM). The obtained results from FT-IR, {sup 1}H NMR and GPC showed that the pluronics effectively conjugated on the dendrimer. The molecular weight of four PAMAM G4.0-Pluronics and its morphologies are in range of 200.15–377.14 kDa and around 60–180 nm in diameter by TEM, respectively. Loading efficiency and release of hydrophobic fluorouracil (5-FU) anticancer drug were evaluated by HPLC; Interesting that the dendrimer nanocarrier was conjugated with the highly lipophilic pluronic P123 (G4.0-P123) exhibiting a higher drug loading efficiency (up to 76.25%) in comparison with another pluronics. Live/dead fibroblast cell staining assay mentioned that all conjugated nanocarriers are highly biocompatible. The drug-loaded nanocarriers also indicated a highly anti-proliferative activity against MCF-7 breast cancer cell. The obtained results demonstrated a great potential of the highly lipophilic pluronics-conjugated nanocarriers in hydrophobic drugs delivery for biomedical applications. - Highlights: • Biocompatible pluronic-conjugated polyamidoamine dendrimers were prepared at nanoscale for drug delivery. • The dendrimer nanocarrier was decorated with a lipophilic pluronic exhibiting a higher drug loading efficiency. • The pluronic-functionalized nanocarriers demonstrated a great potential for delivering hydrophobic drugs.

  15. Molecularly precise dendrimer-drug conjugates with tunable drug release for cancer therapy.

    Science.gov (United States)

    Zhou, Zhuxian; Ma, Xinpeng; Murphy, Caitlin J; Jin, Erlei; Sun, Qihang; Shen, Youqing; Van Kirk, Edward A; Murdoch, William J

    2014-10-06

    The structural preciseness of dendrimers makes them perfect drug delivery carriers, particularly in the form of dendrimer-drug conjugates. Current dendrimer-drug conjugates are synthesized by anchoring drug and functional moieties onto the dendrimer peripheral surface. However, functional groups exhibiting the same reactivity make it impossible to precisely control the number and the position of the functional groups and drug molecules anchored to the dendrimer surface. This structural heterogeneity causes variable pharmacokinetics, preventing such conjugates to be translational. Furthermore, the highly hydrophobic drug molecules anchored on the dendrimer periphery can interact with blood components and alter the pharmacokinetic behavior. To address these problems, we herein report molecularly precise dendrimer-drug conjugates with drug moieties buried inside the dendrimers. Surprisingly, the drug release rates of these conjugates were tailorable by the dendrimer generation, surface chemistry, and acidity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Cholesterol-conjugated supramolecular assemblies of low generations polyamidoamine dendrimers for enhanced EGFP plasmid DNA transfection

    Energy Technology Data Exchange (ETDEWEB)

    Golkar, Nasim; Samani, Soliman Mohammadi; Tamaddon, Ali Mohammad, E-mail: amtamadon@gmail.com [Shiraz University of Medical Sciences, Department of Pharmaceutics, School of Pharmacy (Iran, Islamic Republic of)

    2016-05-15

    Aimed to prepare an enhanced gene delivery system with low cytotoxicity and high transfection efficiency, various cholesterol-conjugated derivates of low generation polyamidoamine (PAMAM) dendrimers were prepared. The conjugates were characterized by TNBS assay, FTIR, and {sup 1}H-NMR spectroscopy. Self-assembly of the dendrimer conjugates (G1-Chol, G2-Chol, and G3-Chol) was investigated by pyrene assay. Following formation of the complexes between enhanced green fluorescence protein plasmid and the dendrimer conjugates at various N (primary amine)/P (phosphate) mole ratios, plasmid condensation, biologic stability, cytotoxicity, and protein expression were investigated. The conjugates self-assembled into micellar dispersions with the critical micelle concentration values (<50 µg/ml) depending on the dendrimer generation and cholesterol/amine mole ratio. Cholesterol conjugation resulted in higher resistance of the condensed plasmid DNA in a competition assay with heparin sulfate. Also, the transfection efficiency was determined higher for the cholesterol conjugates than unmodified dendrimers in HepG2 cells, showing the highest for G2-Chol at 40 % degree of cholesterol modification (G2-Chol{sub 40 %}) among various dendrimer generations. Interestingly, such conjugate showed a complete protection of plasmid against serum nucleases. Our results confirmed that the cholesterol conjugation to PAMAM dendrimers of low generations bearing little cytotoxicity improves their several physicochemical and biological characteristics required for an enhanced delivery of plasmid DNA into cells.

  17. Peptide- and saccharide-conjugated dendrimers for targeted drug delivery: a concise review

    Science.gov (United States)

    Liu, Jie; Gray, Warren D.; Davis, Michael E.; Luo, Ying

    2012-01-01

    Dendrimers comprise a category of branched materials with diverse functions that can be constructed with defined architectural and chemical structures. When decorated with bioactive ligands made of peptides and saccharides through peripheral chemical groups, dendrimer conjugates are turned into nanomaterials possessing attractive binding properties with the cognate receptors. At the cellular level, bioactive dendrimer conjugates can interact with cells with avidity and selectivity, and this function has particularly stimulated interests in investigating the targeting potential of dendrimer materials for the design of drug delivery systems. In addition, bioactive dendrimer conjugates have so far been studied for their versatile capabilities to enhance stability, solubility and absorption of various types of therapeutics. This review presents a brief discussion on three aspects of the recent studies to use peptide- and saccharide-conjugated dendrimers for drug delivery: (i) synthesis methods, (ii) cell- and tissue-targeting properties and (iii) applications of conjugated dendrimers in drug delivery nanodevices. With more studies to elucidate the structure–function relationship of ligand–dendrimer conjugates in transporting drugs, the conjugated dendrimers hold promise to facilitate targeted delivery and improve drug efficacy for discovery and development of modern pharmaceutics. PMID:23741608

  18. Aptamer-conjugated dendrimer-modified quantum dots for glioblastoma cells imaging

    International Nuclear Information System (INIS)

    Li Zhiming; Huang Peng; He Rong; Bao Chenchen; Cui Daxiang; Zhang Xiaomin; Ren Qiushi

    2009-01-01

    Targeted quantum dots have shown potential as a platform for development of cancer imaging. Aptamers have recently been demonstrated as ideal candidates for molecular targeting applications. In present work, polyamidoamine dendrimers were used to modify surface of quantum dots and improve their solubility in water solution. Then, dendrimer-modified quantum dots were conjugated with DNA aptamer, GBI-10, can recognize the extracellular matrix protein tenascin-C on the surface of human glioblastoma cells. The dendrimer-modified quantum dots exhibit water-soluble, high quantum yield, and good biocompatibility. Aptamer-conjugated quantum dots can specifically target U251 human glioblastoma cells. High-performance aptamer-conjugated dendrimers modified quantum dot-based nanoprobes have great potential in application such as cancer imaging.

  19. Preclinical studies of dendrimer prodrugs.

    Science.gov (United States)

    Kojima, Chie

    2015-01-01

    Dendrimers are synthetic macromolecules with well-defined structures bearing a wide variety of functional groups on their periphery. These groups can be used to conjugate bioactive molecules such as drugs, ligands and imaging agents. Dendrimer prodrugs can be used to improve the water solubility and pharmacokinetic properties of the corresponding free drugs. This article summarizes preclinical studies pertaining to the use of drug-dendrimer conjugates as dendrimer prodrugs for the treatments of various diseases, including cancer and inflammatory diseases. A wide range of anticancer drugs have been conjugated to dendrimers via biodegradable linkers. The side effects of the parent drugs can be markedly reduced using dendrimer prodrugs, with some drugs showing improved efficacy. Anti-inflammatory agents have also been conjugated to dendrimers and used to treat a number of inflammatory diseases. Drug-dendrimer conjugates are preferable to drug-dendrimer complexes, where the use of degradable linkers is critical to the release of the drug. Polyethylene glycol and/or ligands can be added to a dendrimer prodrug, which is useful for the targeting of affected tissues. Imaging probes can also be incorporated into dendrimer prodrugs for the simultaneous delivery of therapeutic and diagnostic agents as 'theranostics.'

  20. Development of Tat-Conjugated Dendrimer for Transdermal DNA Vaccine Delivery.

    Science.gov (United States)

    Bahadoran, Azadeh; Moeini, Hassan; Bejo, Mohd Hair; Hussein, Mohd Zobir; Omar, Abdul Rahman

    In order to enhance cellular uptake and to facilitate transdermal delivery of DNA vaccine, polyamidoamine (PAMAM) dendrimers conjugated with HIV transactivator of transcription (TAT) was developed. First, the plasmid DNA (pIRES-H5/GFP) nanoparticle was formulated using PAMAM dendrimer and TAT peptide and then characterized for surface charge, particle size, DNA encapsulation and protection of the pIRES-H5/GFP DNA plasmid to enzymatic digestion. Subsequently, the potency of the TAT-conjugated dendrimer for gene delivery was evaluated through in vitro transfection into Vero cells followed by gene expression analysis including western blotting, fluorescent microscopy and PCR. The effect of the TAT peptide on cellular uptake of DNA vaccine was studied by qRT-PCR and flow cytometry. Finally, the ability of TAT-conjugated PAMAM dendrimer for transdermal delivery of the DNA plasmid was assessed through artificial membranes followed by qRT-PCR and flow cytometry. TAT-conjugated PAMAM dendrimer showed the ability to form a compact and nanometre-sized polyplexes with the plasmid DNA, having the size range of 105 to 115 nm and a positive charge of +42 to +45 mV over the N/P ratio of 6:1(+/-).  In vitro transfection analysis into Vero cells confirms the high potency of TAT-conjugated PAMAM dendrimer to enhance the cellular uptake of DNA vaccine.  The permeability value assay through artificial membranes reveals that TAT-conjugated PAMAM has more capacity for transdermal delivery of the DNA compared to unmodified PAMAM dendrimer (Pdendrimer is a promising non-viral vector for transdermal use.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  1. Dendrimer-conjugated peptide vaccine enhances clearance of Chlamydia trachomatis genital infection.

    Science.gov (United States)

    Ganda, Ingrid S; Zhong, Qian; Hali, Mirabela; Albuquerque, Ricardo L C; Padilha, Francine F; da Rocha, Sandro R P; Whittum-Hudson, Judith A

    2017-07-15

    Peptide-based vaccines have emerged in recent years as promising candidates in the prevention of infectious diseases. However, there are many challenges to maintaining in vivo peptide stability and enhancement of peptide immunogenicity to generate protective immunity which enhances clearance of infections. Here, a dendrimer-based carrier system is proposed for peptide-based vaccine delivery, and shows its anti-microbial feasibility in a mouse model of Chlamydia trachomatis. Chlamydiae are the most prevalent sexually transmitted bacteria worldwide, and also the causal agent of trachoma, the leading cause of preventable infectious blindness. In spite of the prevalence of this infectious agent and the many previous vaccine-related studies, there is no vaccine commercially available. The carrier system proposed consists of generation 4, hydroxyl-terminated, polyamidoamine (PAMAM) dendrimers (G4OH), to which a peptide mimic of a chlamydial glycolipid antigen-Peptide 4 (Pep4, AFPQFRSATLLL) was conjugated through an ester bond. The ester bond between G4OH and Pep4 is expected to break down mainly in the intracellular environment for antigen presentation. Pep4 conjugated to dendrimer induced Chlamydia-specific serum antibodies after subcutaneous immunizations. Further, this new vaccine formulation significantly protected immunized animals from vaginal challenge with infectious Chlamydia trachomatis, and it reduced infectious loads and tissue (genital tract) damage. Pep4 conjugated to G4OH or only mixed with peptide provided enhanced protection compared to Pep4 and adjuvant (i.e. alum), suggesting a potential adjuvant effect of the PAMAM dendrimer. Combined, these results demonstrate that hydroxyl-terminated PAMAM dendrimer is a promising polymeric nanocarrier platform for the delivery of peptide vaccines and this approach has potential to be expanded to other infectious intracellular bacteria and viruses of public health significance. Copyright © 2017 Elsevier B.V. All

  2. Evaluation of anti-HER2 scFv-conjugated PLGA–PEG nanoparticles on 3D tumor spheroids of BT474 and HCT116 cancer cells

    International Nuclear Information System (INIS)

    Le, Thi Thuy Duong; Pham, Thu Hong; Ngo, Thi Hong Giang; Le, Quang Huan; Nguyen, Trong Nghia; Hoang, Thi My Nhung

    2016-01-01

    Three-dimensional culture cells (spheroids) are one of the multicellular culture models that can be applied to anticancer chemotherapeutic development. Multicellular spheroids more closely mimic in vivo tumor-like patterns of physiologic environment and morphology. In previous research, we designed docetaxel-loaded pegylated poly(D, L-lactide-co-glycolide) nanoparticles conjugated with anti-HER2 single chain antibodies (scFv–Doc–PLGA–PEG) and evaluated them in 2D cell culture. In this study, we continuously evaluate the cellular uptake and cytotoxic effect of scFv–Doc–PLGA–PEG on a 3D tumor spheroid model of BT474 (HER2-overexpressing) and HCT116 (HER2-underexpressing) cancer cells. The results showed that the nanoparticle formulation conjugated with scFv had a significant internalization effect on the spheroids of HER2-overexpressing cancer cells as compared to the spheroids of HER2-underexpressing cancer cells. Therefore, cytotoxic effects of targeted nanoparticles decreased the size and increased necrotic score of HER2-overexpressing tumor spheroids. Thus, these scFv–Doc–PLGA–PEG nanoparticles have potential for active targeting for HER2-overexpressing cancer therapy. In addition, BT474 and HCT116 spheroids can be used as a tumor model for evaluation of targeting therapies. (paper)

  3. Internalization and Subcellular Trafficking of Poly-l-lysine Dendrimers Are Impacted by the Site of Fluorophore Conjugation.

    Science.gov (United States)

    Avaritt, Brittany R; Swaan, Peter W

    2015-06-01

    Internalization and intracellular trafficking of dendrimer-drug conjugates play an important role in achieving successful drug delivery. In this study, we aimed to elucidate the endocytosis mechanisms and subcellular localization of poly-l-lysine (PLL) dendrimers in Caco-2 cells. We also investigated the impact of fluorophore conjugation on cytotoxicity, uptake, and transepithelial transport. Oregon green 514 (OG) was conjugated to PLL G3 at either the dendrimer periphery or the core. Chemical inhibitors of clathrin-, caveolin-, cholesterol-, and dynamin-mediated endocytosis pathways and macropinocytosis were employed to establish internalization mechanisms, while colocalization with subcellular markers was used to determine dendrimer trafficking. Cell viability, internalization, and uptake were all influenced by the site of fluorophore conjugation. Uptake was found to be highly dependent on cholesterol- and dynamin-mediated endocytosis as well as macropinocytosis. Dendrimers were trafficked to endosomes and lysosomes, and subcellular localization was impacted by the fluorophore conjugation site. The results of this study indicate that PLL dendrimers exploit multiple pathways for cellular entry, and internalization and trafficking can be impacted by conjugation. Therefore, design of dendrimer-drug conjugates requires careful consideration to achieve successful drug delivery.

  4. Anti-HER2 antibody and ScFvEGFR-conjugated antifouling magnetic iron oxide nanoparticles for targeting and magnetic resonance imaging of breast cancer

    Directory of Open Access Journals (Sweden)

    Chen H

    2013-10-01

    Full Text Available Hongwei Chen,1,* Liya Wang,1,2,* Qiqi Yu,1,2 Weiping Qian,3 Diana Tiwari,1 Hong Yi,4 Andrew Y Wang,5 Jing Huang,1,2 Lily Yang,3 Hui Mao1,2 1Department of Radiology and Imaging Sciences, 2Center for Systems Imaging, 3Department of Surgery, Emory University School of Medicine, 4Robert Apkarian Electron Microscopy Core, Emory University, Atlanta, GA, 5Ocean NanoTech LLC, Springdale, AK, USA *These authors contributed equally to this work Abstract: Antifouling magnetic iron oxide nanoparticles (IONPs coated with block copolymer poly(ethylene oxide-block-poly(γ-methacryloxypropyltrimethoxysilane (PEO-b-PγMPS were investigated for improving cell targeting by reducing nonspecific uptake. Conjugation of a HER2 antibody, Herceptin®, or a single chain fragment (ScFv of antibody against epidermal growth factor receptor (ScFvEGFR to PEO-b-PγMPS-coated IONPs resulted in HER2-targeted or EGFR-targeted IONPs (anti-HER2-IONPs or ScFvEGFR-IONPs. The anti-HER2-IONPs bound specifically to SK-BR-3, a HER2-overexpressing breast cancer cell line, but not to MDA-MB-231, a HER2-underexpressing cell line. On the other hand, the ScFvEGFR-IONPs showed strong reactivity with MDA-MB-231, an EGFR-positive human breast cancer cell line, but not with MDA-MB-453, an EGFR-negative human breast cancer cell line. Transmission electron microscopy revealed internalization of the receptor-targeted nanoparticles by the targeted cancer cells. In addition, both antibody-conjugated and non-antibody-conjugated IONPs showed reduced nonspecific uptake by RAW264.7 mouse macrophages in vitro. The developed IONPs showed a long blood circulation time (serum half-life 11.6 hours in mice and low accumulation in both the liver and spleen. At 24 hours after systemic administration of ScFvEGFR-IONPs into mice bearing EGFR-positive breast cancer 4T1 mouse mammary tumors, magnetic resonance imaging revealed signal reduction in the tumor as a result of the accumulation of the targeted IONPs

  5. Synergistic activity profile of carbosilane dendrimer G2-STE16 in combination with other dendrimers and antiretrovirals as topical anti-HIV-1 microbicide.

    Science.gov (United States)

    Sepúlveda-Crespo, Daniel; Lorente, Raquel; Leal, Manuel; Gómez, Rafael; De la Mata, Francisco J; Jiménez, José Luis; Muñoz-Fernández, M Ángeles

    2014-04-01

    Polyanionic carbosilane dendrimers represent opportunities to develop new anti-HIV microbicides. Dendrimers and antiretrovirals (ARVs) acting at different stages of HIV replication have been proposed as compounds to decrease new HIV infections. Thus, we determined the potential use of our G2-STE16 carbosilane dendrimer in combination with other carbosilane dendrimers and ARVs for the use as topical microbicide against HIV-1. We showed that these combinations obtained 100% inhibition and displayed a synergistic profile against different HIV-1 isolates in our model of TZM.bl cells. Our results also showed their potent activity in the presence of an acidic vaginal or seminal fluid environment and did not activate an inflammatory response. This study is the first step toward exploring the use of different anionic carbosilane dendrimers in combination and toward making a safe microbicide. Therefore, our results support further studies on dendrimer/dendrimer or dendrimer/ARV combinations as topical anti-HIV-1 microbicide. This paper describes the first steps toward the use of anionic carbosilane dendrimers in combination with antivirals to address HIV-1, paving the way to further studies on dendrimer/dendrimer or dendrimer/ARV combinations as topical anti-HIV-1 microbicides. © 2014.

  6. Activated Microglia Targeting Dendrimer-Minocycline Conjugate as Therapeutics for Neuroinflammation.

    Science.gov (United States)

    Sharma, Rishi; Kim, Soo-Young; Sharma, Anjali; Zhang, Zhi; Kambhampati, Siva Pramodh; Kannan, Sujatha; Kannan, Rangaramanujam M

    2017-11-15

    Brain-related disorders have outmatched cancer and cardiovascular diseases worldwide as the leading cause of morbidity and mortality. The lack of effective therapies and the relatively dry central nervous system (CNS) drug pipeline pose formidable challenge. Superior, targeted delivery of current clinically approved drugs may offer significant potential. Minocycline has shown promise for the treatment of neurological diseases owing to its ability to penetrate the blood-brain barrier (BBB) and potency. Despite its potential in the clinic and in preclinical models, the high doses needed to affect a positive therapeutic response have led to side effects. Targeted delivery of minocycline to the injured site and injured cells in the brain can be highly beneficial. Systemically administered hydroxyl poly(amidoamine) (PAMAM) generation-6 (G6) dendrimers have a longer blood circulation time and have been shown to cross the impaired BBB. We have successfully prepared and characterized the in vitro efficacy and in vivo targeting ability of hydroxyl-G6 PAMAM dendrimer-9-amino-minocycline conjugate (D-mino). Minocycline is a challenging drug to carry out chemical transformations due to its inherent instability. We used a combination of a highly efficient and mild copper catalyzed azide-alkyne click reaction (CuAAC) along with microwave energy to conjugate 9-amino-minocycline (mino) to the dendrimer surface via enzyme responsive linkages. D-mino was further evaluated for anti-inflammatory and antioxidant activity in lipopolysaccharides-activated murine microglial cells. D-mino conjugates enhanced the intracellular availability of the drug due to their rapid uptake, suppressed inflammatory cytokine tumor necrosis factor α (TNF-α) production, and reduced oxidative stress by suppressing nitric oxide production, all significantly better than the free drug. Fluorescently labeled dendrimer conjugate (Cy5-D-mino) was systematically administered (intravenous, 55 mg/kg) on postnatal

  7. One-, two- and three-photon spectroscopy of π-conjugated dendrimers: cooperative enhancement and coherent domains

    International Nuclear Information System (INIS)

    Drobizhev, M.; Rebane, A.; Suo, Z.; Spangler, C.W.

    2005-01-01

    We use wavelength tunable femtosecond pulses to measure intrinsic (simultaneous) two-photon absorption (2PA) and three-photon absorption (3PA) molecular cross section in two series of π-conjugated dendrimers built of identical 4,4'-bis(diphenylamino) stilbene (BDPAS) and 4,4'-bis(diphenylamino) distyrylbenzene (BDPADSB) repeat units. Record large 2PA cross sections, σ 2 =10 -46 cm 4 s are obtained for the largest second-generation BDPAS-based dendrimer, as well as zeroth-generation 4-arm BDPADSB-based dendrimer. In both series, maximum 2PA cross section increases nonlinearly with the number of π-electrons, whereas for higher generations this dependence turns to linear one. 3PA cross section also increases nonlinearly with the size of the system in the series of BDPAS-based molecules, amounting a record large value, σ 3 =10 -79 cm 6 s 2 , for the largest, second-generation dendrimer. We interpret these results in terms of direct inter-branch conjugation, which facilitates cooperative enhancement of the nonlinear-optical response. We propose a simple model which allows us to determine the effective size of coherent domains (extent of conjugation), which, in turn, determines the optimum dendrimer size for most efficient nonlinear response

  8. Transport of surface engineered polyamidoamine (PAMAM) dendrimers across IPEC-J2 cell monolayers.

    Science.gov (United States)

    Pisal, Dipak S; Yellepeddi, Venkata K; Kumar, Ajay; Palakurthi, Srinath

    2008-11-01

    The aim of our study was to prepare arginine-and ornithine-conjugated Polyamidoamine (PAMAM) dendrimers and study their permeability across IPEC-J2 cell monolayers, a new intestinal cell line model for drug absorption studies. Arginine and ornithine were conjugated to the amine terminals of the PAMAM(G4) dendrimers by Fmoc synthesis. The apical-to-basolateral (AB) and basolateral-to-apical (BA) apparent permeability coefficients (P(app)) for the PAMAM dendrimers increased by conjugating the dendrimers with both of these polyamines. The enhancement in permeability was dependent on the dendrimer concentration and duration of incubation. Correlation between monolayer permeability and the decrease in transepithelial electrical resistance (TEER) with the PAMAM dendrimers and the polyamine-conjugated dendrimers suggests that paracellular transport is one of the mechanisms of transport across the epithelial cells. Cytotoxicity of these surface-modified dendrimers was evaluated in IPEC-J2 cells by MTT (methylthiazoletetrazolium) assay. Arginine-conjugated dendrimers were insignificantly more toxic than PAMAM dendrimer as well as ornithine-conjugated dendrimers. Though investigations on the possible involvement of other transport mechanisms are in progress, results of the present study suggest the potential of dendrimer-polyamine conjugates as the carriers for antigen/drug delivery through the oral mucosa.

  9. Enhanced A3 adenosine receptor selectivity of multivalent nucleoside-dendrimer conjugates

    Directory of Open Access Journals (Sweden)

    Shainberg Asher

    2008-10-01

    Full Text Available Abstract Background An approach to use multivalent dendrimer carriers for delivery of nucleoside signaling molecules to their cell surface G protein-coupled receptors (GPCRs was recently introduced. Results A known adenosine receptor (AR agonist was conjugated to polyamidoamine (PAMAM dendrimer carriers for delivery of the intact covalent conjugate to on the cell surface. Depending on the linking moiety, multivalent conjugates of the N6-chain elongated functionalized congener ADAC (N6-[4-[[[4-[[[(2-aminoethylamino]carbonyl]methyl]anilino]carbonyl]methyl]phenyl]-adenosine achieved unanticipated high selectivity in binding to the cytoprotective human A3 AR, a class A GPCR. The key to this selectivity of > 100-fold in both radioreceptor binding (Ki app = 2.4 nM and functional assays (EC50 = 1.6 nM in inhibition of adenylate cyclase was maintaining a free amino group (secondary in an amide-linked chain. Attachment of neutral amide-linked chains or thiourea-containing chains preserved the moderate affinity and efficacy at the A1 AR subtype, but there was no selectivity for the A3 AR. Since residual amino groups on dendrimers are associated with cytotoxicity, the unreacted terminal positions of this A3 AR-selective G2.5 dendrimer were present as carboxylate groups, which had the further benefit of increasing water-solubility. The A3 AR selective G2.5 dendrimer was also visualized binding the membrane of cells expressing the A3 receptor but did not bind cells that did not express the receptor. Conclusion This is the first example showing that it is feasible to modulate and even enhance the pharmacological profile of a ligand of a GPCR based on conjugation to a nanocarrier and the precise structure of the linking group, which was designed to interact with distal extracellular regions of the 7 transmembrane-spanning receptor. This ligand tool can now be used in pharmacological models of tissue rescue from ischemia and to probe the existence of A3 AR

  10. Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates.

    Science.gov (United States)

    Nwe, K; Bernardo, M; Regino, C A S; Williams, M; Brechbiel, M W

    2010-08-15

    In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N',N',N'',N''-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex(R) G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1, respectively. Molar relaxivity measured at pH 7.4, 22 degrees C, and 3T are comparable (29.5 vs 26.9 mM(-1)s(-1)), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t(1/2)=16 vs 29 min). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties. Published by Elsevier Ltd.

  11. Polyamidoamine (PAMAM) Dendrimer Conjugates of Clickable Agonists of the A3 Adenosine Receptor and Coactivation of the P2Y14 Receptor by a Tethered Nucleotide

    Energy Technology Data Exchange (ETDEWEB)

    Tosh, Dilip, K. [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health; Yoo, Lena S. [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health; Chinn, Moshe [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health; Hong, Kunlun [ORNL; Kilbey, II, S Michael [ORNL; Barrett, Matthew O. [University of North Carolina School of Medicine; Fricks, Ingrid P. [University of North Carolina School of Medicine; Harden, T. Kendall [University of North Carolina School of Medicine; Jacobson, Kenneth A. [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health

    2010-01-01

    We previously synthesized a series of potent and selective A{sub 3} adenosine receptor (AR) agonists (North-methanocarba nucleoside 5{prime}-uronamides) containing dialkyne groups on extended adenine C2 substituents. We coupled the distal alkyne of a 2-octadiynyl nucleoside by Cu(I)-catalyzed 'click' chemistry to azide-derivatized G4 (fourth-generation) PAMAM dendrimers to form triazoles. A{sub 3}AR activation was preserved in these multivalent conjugates, which bound with apparent Ki of 0.1-0.3 nM. They were substituted with nucleoside moieties, solely or in combination with water-solubilizing carboxylic acid groups derived from hexynoic acid. A comparison with various amide-linked dendrimers showed that triazole-linked conjugates displayed selectivity and enhanced A{sub 3}AR affinity. We prepared a PAMAM dendrimer containing equiproportioned peripheral azido and amino groups for conjugation of multiple ligands. A bifunctional conjugate activated both A{sub 3} and P2Y{sub 14} receptors (via amide-linked uridine-5{prime}-diphosphoglucuronic acid), with selectivity in comparison to other ARs and P2Y receptors. This is the first example of targeting two different GPCRs with the same dendrimer conjugate, which is intended for activation of heteromeric GPCR aggregates. Synergistic effects of activating multiple GPCRs with a single dendrimer conjugate might be useful in disease treatment.

  12. Permeability of surface modified polyamidoamine (PAMAM) dendrimers across Caco-2 cell monolayers

    OpenAIRE

    Yellepeddi, Venkata K.; Pisal, Dipak S.; Kumar, Ajay; Kaushik, Radhey S.; Hildreth, Michael B.; Guan, Xiangming; Palakurthi, Srinath

    2007-01-01

    Aim of this study was to prepare polyamine-conjugated PAMAM dendrimers and study their permeability across Caco-2 cell monolayers. Polyamines, namely, arginine and ornithine were conjugated to the amine terminals of the G4 PAMAM dendrimers by Fmoc synthesis. The apical-to-basolateral (AB) and basolateral-to-apical (BA) apparent permeability coefficients (Papp) for the PAMAM dendrimers increased by conjugating the dendrimers with both of the polyamines. The enhancement in permeability was depe...

  13. Polymer–lipid hybrid anti-HER2 nanoparticles for targeted salinomycin delivery to HER2-positive breast cancer stem cells and cancer cells

    Directory of Open Access Journals (Sweden)

    Li J

    2017-09-01

    Full Text Available Jun Li,1,* Wenqing Xu,2,* Xiaoli Yuan,3,* Huaiwen Chen,3 Hao Song,1,4 Bingquan Wang,5 Jun Han5 1College of Pharmacy, Liaocheng University, Liaocheng, Shandong, 2Railway Police College, Zhengzhou, 3Department of Cadre Health Care, Nanjing General Hospital of Nanjing Military Command, Nanjing, Jiangsu, 4Centre for Stem Cell & Regenerative Medicine, Liaocheng People’s Hospital, 5Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng, Shandong, China *These authors contributed equally to this work Purpose: Breast cancer stem cells (CSCs are responsible for the initiation, recurrence, and metastasis of breast cancer. Sufficient evidence has established that breast cancer cells can spontaneously turn into breast CSCs. Thus, it is essential to simultaneously target breast CSCs and cancer cells to maximize the efficacy of breast cancer therapy. HER2 has been found to be overexpressed in both breast CSCs and cancer cells. We developed salinomycin-loaded polymer–lipid hybrid anti-HER2 nanoparticles (Sali-NP-HER2 to target both HER2-positive breast CSCs and cancer cells.Methods: The antitumor activity of Sali-NP-HER2 constructed by conjugating anti-HER2 antibodies to polymer–lipid salinomycin nanoparticles was evaluated in vitro and in vivo.Results: Sali-NP-HER2 efficiently bound to HER2-positive breast CSCs and cancer cells, resulting in enhanced cytotoxic effects compared with non-targeted nanoparticles or salinomycin. In mice bearing breast cancer xenografts, administration of Sali-NP-HER2 exhibited superior efficacy in inhibiting tumor growth. Sali-NP-HER2 reduced the breast tumorsphere formation rate and the proportion of breast CSCs more effectively than non-targeted nanoparticles or salinomycin alone.Conclusion: Sali-NP-HER2 represents a promising approach in treating HER2-positive breast cancer by targeting both breast CSCs and cancer cells. Keywords: nanoparticles, breast cancer, cancer stem cells, salinomycin, HER2

  14. Recent Findings Concerning PAMAM Dendrimer Conjugates with Cyclodextrins as Carriers of DNA and RNA

    Directory of Open Access Journals (Sweden)

    Keiichi Motoyama

    2009-08-01

    Full Text Available We have evaluated the potential use of various polyamidoamine (PAMAM dendrimer [dendrimer, generation (G 2-4] conjugates with cyclodextrins (CyDs as novel DNA and RNA carriers. Among the various dendrimer conjugates with CyDs, the dendrimer (G3 conjugate with α-CyD having an average degree of substitution (DS of 2.4 [α-CDE (G3, DS2] displayed remarkable properties as DNA, shRNA and siRNA delivery carriers through the sensor function of α-CDEs toward nucleic acid drugs, cell surface and endosomal membranes. In an attempt to develop cell-specific gene transfer carriers, we prepared sugar-appended α-CDEs. Of the various sugar-appended α-CDEs prepared, galactose- or mannose-appended α-CDEs provided superior gene transfer activity to α-CDE in various cells, but not cell-specific gene delivery ability. However, lactose-appended α-CDE [Lac-α-CDE (G2] was found to possess asialoglycoprotein receptor (AgpR-mediated hepatocyte-selective gene transfer activity, both in vitro and in vivo. Most recently, we prepared folate-poly(ethylene glycol-appended α-CDE [Fol-PαC (G3] and revealed that Fol-PαC (G3 imparted folate receptor (FR-mediated cancer cell-selective gene transfer activity. Consequently, α-CDEs bearing integrated, multifunctional molecules may possess the potential to be novel carriers for DNA, shRNA and siRNA.

  15. Targeting breast carcinoma with radioiodinated anti-HER2 Nanobody

    International Nuclear Information System (INIS)

    Pruszynski, Marek; Koumarianou, Eftychia; Vaidyanathan, Ganesan; Revets, Hilde; Devoogdt, Nick; Lahoutte, Tony; Zalutsky, Michael R.

    2013-01-01

    Introduction: With a molecular weight an order of magnitude lower than antibodies but possessing comparable affinities, Nanobodies (Nbs) are attractive as targeting agents for cancer diagnosis and therapy. An anti-HER2 Nb could be utilized to determine HER2 status in breast cancer patients prior to trastuzumab treatment. This provided motivation for the generation of HER2-specific 5F7GGC Nb, its radioiodination and evaluation for targeting HER2 expressing tumors. Methods: 5F7GGC Nb was radioiodinated with 125 I using Iodogen and with 131 I using the residualizing agent N ε -(3-[ 131 I]iodobenzoyl)-Lys 5 -N α -maleimido-Gly 1 -GEEEK ([ 131 I]IB-Mal-D-GEEEK) used previously successfully with intact antibodies. Paired-label internalization assays using BT474M1 cells and tissue distribution experiments in athymic mice bearing BT474M1 xenografts were performed to compare the two labeled Nb preparations. Results: The radiochemical yields for Iodogen and [ 131 I]IB-Mal-D-GEEEK labeling were 83.6 ± 5.0% (n = 10) and 59.6 ± 9.4% (n = 15), respectively. The immunoreactivity of labeled proteins was preserved as confirmed by in vitro and in vivo binding to tumor cells. Biodistribution studies showed that Nb radiolabeled using [ 131 I]IB-Mal-D-GEEEK, compared with the directly labeled Nb, had a higher tumor uptake (4.65 ± 0.61% ID/g vs. 2.92 ± 0.24% ID/g at 8 h), faster blood clearance, lower accumulation in non-target organs except kidneys, and as a result, higher concomitant tumor-to-blood and tumor-to-tissue ratios. Conclusions: Taken together, these results demonstrate that 5F7GGC anti-HER2 Nb labeled with residualizing [ 131 I]IB-Mal-D-GEEEK had better tumor targeting properties compared to the directly labeled Nb suggesting the potential utility of this Nb conjugate for SPECT ( 129 I) and PET imaging ( 124 I) of patients with HER2-expressing tumors.

  16. Hyperbranched–dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, Seyyed Jamal [Ferdowsi University of Mashhad, Department of Chemistry, Faculty of Science (Iran, Islamic Republic of); Gholami, Leila [Mashhad University of Medical Sciences, Department of Modern Sciences and Technologies, School of Medicine (Iran, Islamic Republic of); Askarian, Saeedeh [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of); Darroudi, Majid [Mashhad University of Medical Sciences, Nuclear Medicine Research Center (Iran, Islamic Republic of); Massoudi, Abdolhossein [University of Payam noor, Department of Chemistry (Iran, Islamic Republic of); Rezaee, Mehdi; Kazemi Oskuee, Reza, E-mail: Oskueekr@mums.ac.ir [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of)

    2017-02-15

    The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate–PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI–PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI–PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)–dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

  17. Hyperbranched-dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

    Science.gov (United States)

    Alavi, Seyyed Jamal; Gholami, Leila; Askarian, Saeedeh; Darroudi, Majid; Massoudi, Abdolhossein; Rezaee, Mehdi; Kazemi Oskuee, Reza

    2017-02-01

    The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate-PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI-PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI-PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)-dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

  18. Transport and biodistribution of dendrimers across human fetal membranes: implications for intravaginal administration of dendrimer-drug conjugates.

    Science.gov (United States)

    Menjoge, Anupa R; Navath, Raghavendra S; Asad, Abbas; Kannan, Sujatha; Kim, Chong J; Romero, Roberto; Kannan, Rangaramanujam M

    2010-06-01

    Dendrimers are emerging as promising topical antimicrobial agents, and as targeted nanoscale drug delivery vehicles. Topical intravaginal antimicrobial agents are prescribed to treat the ascending genital infections in pregnant women. The fetal membranes separate the extra-amniotic space and fetus. The purpose of the study is to determine if the dendrimers can be selectively used for local intravaginal application to pregnant women without crossing the membranes into the fetus. In the present study, the transport and permeability of PAMAM (poly (amidoamine)) dendrimers, across human fetal membrane (using a side by side diffusion chamber), and its biodistribution (using immunofluorescence) are evaluated ex-vivo. Transport across human fetal membranes (from the maternal side) was evaluated using Fluorescein (FITC), an established transplacental marker (positive control, size approximately 400 Da) and fluorophore-tagged G(4)-PAMAM dendrimers (approximately 16 kDa). The fluorophore-tagged G(4)-PAMAM dendrimers were synthesized and characterized using (1)H NMR, MALDI TOF MS and HPLC analysis. Transfer was measured across the intact fetal membrane (chorioamnion), and the separated chorion and amnion layers. Over a 5 h period, the dendrimer transport across all the three membranes was less than dendrimer (5.8 x 10(-8) cm(2)/s). The biodistribution showed that the dendrimers were largely present in interstitial spaces in the decidual stromal cells and the chorionic trophoblast cells (in 2.5-4 h) and surprisingly, to a smaller extent internalized in nuclei of trophoblast cells and nuclei and cytoplasm of stromal cells. Passive diffusion and paracellular transport appear to be the major route for dendrimer transport. The overall findings further suggest that entry of drugs conjugated to dendrimers would be restricted across the human fetal membranes when administered topically by intravaginal route, suggesting new ways of selectively delivering therapeutics to the mother

  19. Effect of methotrexate conjugated PAMAM dendrimers on the viability of MES-SA uterine cancer cells

    Directory of Open Access Journals (Sweden)

    Samreen Khatri

    2014-01-01

    Full Text Available The aim of this work was to synthesize methotrexate (MTX-polyamidoamine (PAMAM dendritic nanoconjugates and to study their effect on cell viability in uterine sarcoma cells. The amide-bonded PAMAM dendrimer-MTX conjugates were prepared by conjugation between the amine-terminated G5 dendrimer and the carboxylic groups of the MTX using a dicyclohexylcarbodiimide coupling reaction. The formation of conjugates was evaluated by ultraviolet (UV and 1 H nuclear magnetic resonance ( 1 H NMR spectroscopy studies. The cell survival of MES-SA cells, a uterine sarcoma cell line, was evaluated in the presence of the dendrimer-MTX nanoconjugate, using appropriate controls. The UV and 1 H NMR study confirmed the formation of covalent bonds between the drug and the dendrimer. The cell viability study indicated that the nanoconjugates had significantly improved cell killing compared to the free MTX.

  20. Survival benefit of anti-HER2 therapy after whole-brain radiotherapy in HER2-positive breast cancer patients with brain metastasis.

    Science.gov (United States)

    Zhang, Qian; Chen, Jian; Yu, Xiaoli; Cai, Gang; Yang, Zhaozhi; Cao, Lu; Hu, Chaosu; Guo, Xiaomao; Sun, Jing; Chen, Jiayi

    2016-09-01

    We aimed to assess the survival benefit of epidermal growth factor receptor 2 (HER2)-positive breast cancer patients with brain metastasis (BM) after whole-brain radiotherapy (WBRT) in combination with systemic treatments, especially anti-HER2 therapy. This retrospective study analyzed the overall survival (OS) of 60 HER2-positive breast cancer patients with BM after WBRT in combination with systemic treatments. Among them, 42 patients received chemotherapy while 18 patients did not receive after WBRT. With regard to anti-HER2 therapy, after WBRT, 17 patients received anti-HER2 treatment without prior adjuvant trastuzumab-based therapy, 7 patients received anti-HER2 treatment with prior adjuvant trastuzumab-based therapy, and 36 patients did not receive further anti-HER2 treatment. All patients were followed up regularly until January 23, 2013. The median OS of patients with BM was 12 months. Patients who received anti-HER2 therapy and chemotherapy after WBRT had significantly better survival compared with patients who did not receive further treatment. Patients who received anti-HER2 treatment after WBRT but did not receive adjuvant trastuzumab-based therapy for early breast cancer had better OS, followed by patients who received anti-HER2 agent both in adjuvant treatment and after WBRT and patients who did not receive anti-HER2 treatment. Multivariate analysis showed that Karnofsky Performance Status, control of extracranial metastases, chemotherapy after WBRT, and anti-HER2 therapy combined with WBRT were all independent predictors for OS. Both chemotherapy and anti-HER2 therapy after WBRT could improve OS. Moreover, patients without prior exposure to adjuvant anti-HER2 treatment may have survival benefit superior to those of patients with prior exposure.

  1. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Swami, Rajan; Singh, Indu [National Institute of Pharmaceutical Education & Research (NIPER), Department of Pharmaceutics (India); Kulhari, Hitesh [CSIR-Indian Institute of Chemical Technology, Medicinal Chemistry & Pharmacology Division (India); Jeengar, Manish Kumar [National Institute of Pharmaceutical Education & Research (NIPER), Departmentof Pharmacology (India); Khan, Wahid, E-mail: wahid@niperhyd.ac.in; Sistla, Ramakrishna, E-mail: sistla@iict.res.in, E-mail: rksistla@yahoo.com [National Institute of Pharmaceutical Education & Research (NIPER), Department of Pharmaceutics (India)

    2015-06-15

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by {sup 1}HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere{sup ®}). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors.

  2. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    International Nuclear Information System (INIS)

    Swami, Rajan; Singh, Indu; Kulhari, Hitesh; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2015-01-01

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by 1 HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere ® ). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors

  3. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    Science.gov (United States)

    Swami, Rajan; Singh, Indu; Kulhari, Hitesh; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2015-06-01

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by 1HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere®). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors.

  4. A single-layer peptide nanofiber for enhancing the cytotoxicity of trastuzumab (anti-HER)

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Ruchi; Wagh, Anil; Qian, Steven; Law, Benedict, E-mail: Shek.law@ndsu.edu [College of Pharmacy, Nursing, and Allied Sciences, North Dakota State University, Department of Pharmaceutical Sciences (United States)

    2013-06-15

    A multivalent system is often employed to enhance the effectiveness of a targeted therapy. In the present study, we report a single-layer peptide nanofiber (NFP) as a multivalent targeting platform to improve the cytotoxicity of trastuzumab (anti-HER), a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER-2) in approximately 20 % of breast cancer patients. The trastuzumab-conjugated nanofiber (anti-HER/NFP) was 100 Multiplication-Sign 4 nm in size and was assembled from multiple peptide units (mPEG-BK(FITC)SGASNRA-kldlkldlkldl-CONH{sub 2}). The optimized preparation was attached with approximately 10 antibodies at the surface. Because of an increase in the multivalency, anti-HER/NFP was able to truncate more cell surface HER-2 and, thus, showed an enhanced cytotoxicity toward HER-2 positive SKBr-3 human breast cancer as compared to the free anti-HER. Western blot analysis and fluorescence microscopic studies confirmed that there was a significant downregulation of the HER-2 level and also inhibition of the cell survival cell signaling pathways including the phosphatidylinositol 3-kinase (PI3K) and the mitogen activated protein kinase (MAPK) pathway. Our data suggested that NFP can be useful as a multivalent platform for immunotherapy, especially in combination with other chemotherapeutic agents in the future.

  5. 177Lu-Dendrimer Conjugated to Folate and Bombesin with Gold Nanoparticles in the Dendritic Cavity: A Potential Theranostic Radiopharmaceutical

    Directory of Open Access Journals (Sweden)

    Héctor Mendoza-Nava

    2016-01-01

    Full Text Available 177Lu-labeled nanoparticles conjugated to biomolecules have been proposed as a new class of theranostic radiopharmaceuticals. The aim of this research was to synthesize 177Lu-dendrimer(PAMAM-G4-folate-bombesin with gold nanoparticles (AuNPs in the dendritic cavity and to evaluate the radiopharmaceutical potential for targeted radiotherapy and the simultaneous detection of folate receptors (FRs and gastrin-releasing peptide receptors (GRPRs overexpressed in breast cancer cells. p-SCN-Benzyl-DOTA was conjugated in aqueous-basic medium to the dendrimer. The carboxylate groups of Lys1Lys3(DOTA-bombesin and folic acid were activated with HATU and also conjugated to the dendrimer. The conjugate was mixed with 1% HAuCl4 followed by the addition of NaBH4 and purified by ultrafiltration. Elemental analysis (EDS, particle size distribution (DLS, TEM analysis, UV-Vis, and infrared and fluorescence spectroscopies were performed. The conjugate was radiolabeled using 177LuCl3 or 68GaCl3 and analyzed by radio-HPLC. Studies confirmed the dendrimer functionalization with high radiochemical purity (>95%. Fluorescence results demonstrated that the presence of AuNPs in the dendritic cavity confers useful photophysical properties to the radiopharmaceutical for optical imaging. Preliminary binding studies in T47D breast cancer cells showed a specific cell uptake (41.15±2.72%. 177Lu-dendrimer(AuNP-folate-bombesin may be useful as an optical and nuclear imaging agent for breast tumors overexpressing GRPR and FRs, as well as for targeted radiotherapy.

  6. Effect of increased surface hydrophobicity via drug conjugation on the clearance of inhaled PEGylated polylysine dendrimers.

    Science.gov (United States)

    Haque, Shadabul; McLeod, Victoria M; Jones, Seth; Fung, Sandy; Whittaker, Michael; McIntosh, Michelle; Pouton, Colin; Owen, David J; Porter, Christopher J H; Kaminskas, Lisa M

    2017-10-01

    PEGylated polylysine dendrimers are attractive and well tolerated inhalable drug delivery platforms that have the potential to control the release, absorption kinetics and lung retention time of conjugated drugs. The clinical application of these systems though, would likely require partial substitution of surface PEG groups with drug molecules that are anticipated to alter their lung clearance kinetics and clearance pathways. In the current study, we therefore evaluated the impact of increased surface hydrophobicity via substitution of 50% surface PEG groups with a model hydrophobic drug (α-carboxyl OtButylated methotrexate) on the lung clearance of a Generation 5 PEGylated polylysine dendrimer in rats. PEG substitution with OtBu-methotrexate accelerated lung clearance of the dendrimer by increasing polylysine scaffold catabolism, improving systemic absorption of the intact dendrimer and low molecular weight products of scaffold catabolism, and enhancing mucociliary clearance. These results suggest that the conjugation of hydrophobic drug on the surface of a PEGylated dendrimer is likely to accelerate lung clearance when compared to a fully PEGylated dendrimer. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  7. Preclinical Evaluation of 18F-Labeled Anti-HER2 Nanobody Conjugates for Imaging HER2 Receptor Expression by Immuno-PET.

    Science.gov (United States)

    Vaidyanathan, Ganesan; McDougald, Darryl; Choi, Jaeyeon; Koumarianou, Eftychia; Weitzel, Douglas; Osada, Takuya; Lyerly, H Kim; Zalutsky, Michael R

    2016-06-01

    The human growth factor receptor type 2 (HER2) is overexpressed in breast as well as other types of cancer. Immuno-PET, a noninvasive imaging procedure that could assess HER2 status in both primary and metastatic lesions simultaneously, could be a valuable tool for optimizing application of HER2-targeted therapies in individual patients. Herein, we have evaluated the tumor-targeting potential of the 5F7 anti-HER2 Nanobody (single-domain antibody fragment; ∼13 kDa) after (18)F labeling by 2 methods. The 5F7 Nanobody was labeled with (18)F using the novel residualizing label N-succinimidyl 3-((4-(4-(18)F-fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ((18)F-SFBTMGMB; (18)F-RL-I) and also via the most commonly used (18)F protein-labeling prosthetic agent N-succinimidyl 3-(18)F-fluorobenzoate ((18)F-SFB). For comparison, 5F7 Nanobody was also labeled using the residualizing radioiodination agent N-succinimidyl 4-guanidinomethyl-3-(125)I-iodobenzoate ((125)I-SGMIB). Paired-label ((18)F/(125)I) internalization assays and biodistribution studies were performed on HER2-expressing BT474M1 breast carcinoma cells and in mice with BT474M1 subcutaneous xenografts, respectively. Small-animal PET/CT imaging of 5F7 Nanobody labeled using (18)F-RL-I also was performed. Internalization assays indicated that intracellularly retained radioactivity for (18)F-RL-I-5F7 was similar to that for coincubated (125)I-SGMIB-5F7, whereas that for (18)F-SFB-5F7 was lower than coincubated (125)I-SGMIB-5F7 and decreased with time. BT474M1 tumor uptake of (18)F-RL-I-5F7 was 28.97 ± 3.88 percentage injected dose per gram of tissue (%ID/g) at 1 h and 36.28 ± 14.10 %ID/g at 2 h, reduced by more than 90% on blocking with trastuzumab, indicating HER2 specificity of uptake, and was also 26%-28% higher (P < 0.05) than that of (18)F-SFB-5F7. At 2 h, the tumor-to-blood ratio for (18)F-RL-I-5F7 (47.4 ± 13.1) was significantly higher (P < 0.05) than for (18)F-SFB-5F7 (25.4 ± 10

  8. {sup 186}Re-maSGS-Z{sub HER2:342}, a potential affibody conjugate for systemic therapy of HER2-expressing tumours

    Energy Technology Data Exchange (ETDEWEB)

    Orlova, Anna; Tran, Thuy A. [Uppsala University, Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala (Sweden); Ekblad, Torun; Karlstroem, Amelie Eriksson [Royal Institute of Technology, School of Biotechnology, Division of Molecular Biotechnology, Stockholm (Sweden); Tolmachev, Vladimir [Uppsala University, Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala (Sweden); Uppsala University, Division of Nuclear Medicine, Department of Medical Sciences, Uppsala (Sweden)

    2010-02-15

    Affibody molecules are a novel class of tumour-targeting proteins, which combine small size (7 kDa) and picomolar affinities. The Affibody molecule Z{sub HER2:342} has been suggested for imaging of HER2 expression in order to select patients for trastuzumab therapy. When optimizing chelators for {sup 99m}Tc-labelling, we have found that synthetic Z{sub HER2:342} conjugated with mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) and mercaptoacetyl-glycyl-seryl-glycyl (maGSG) chelators provides relatively low renal uptake of radioactivity and could be suitable for therapy. maGGG-Z{sub HER2:342} and maGSG-Z{sub HER2:342} were labelled with {sup 186}Re and their biodistribution was studied in normal mice. Dosimetric evaluation and tumour targeting to HER2-overexpressed xenografts (SKOV-3) by {sup 186}Re-maGSG-Z{sub HER2:342} were studied. Gluconate-mediated labelling of maGGG-Z{sub HER2:342} and maGSG-Z{sub HER2:342} with {sup 186}Re provided a yield of more than 95% within 60 min. The conjugates were stable and demonstrated specific binding to HER2-expressing SKOV-3 cells. Biodistribution in normal mice demonstrated rapid blood clearance, low accumulation of radioactivity in the kidney and other organs, accumulating free perrhenate. Both {sup 186}Re-maGGG-Z{sub HER2:342} and {sup 186}Re-maGSG-Z{sub HER2:342} demonstrated lower renal uptake than their {sup 99m}Tc-labelled counterparts. {sup 186}Re-maGSG-Z{sub HER2:342} provided the lowest uptake in healthy tissues. Biodistribution of {sup 186}Re-maGSG-Z{sub HER2:342} in nude mice bearing SKOV-3 xenografts showed specific targeting of tumours. Tumour uptake 24 h after injection (5.84{+-}0.54%ID/g) exceeded the concentration in blood by more than 500-fold, and uptake in kidneys by about 8-fold. Preliminary dosimetric evaluation showed that dose-to-tumour should exceed dose-to-kidney by approximately 5-fold. Optimization of chelators improves biodistribution properties of rhenium-labelled small scaffold proteins and enables

  9. Folate coupled poly(ethyleneglycol) conjugates of anionic poly(amidoamine) dendrimer for inflammatory tissue specific drug delivery.

    Science.gov (United States)

    Chandrasekar, Durairaj; Sistla, Ramakrishna; Ahmad, Farhan J; Khar, Roop K; Diwan, Prakash V

    2007-07-01

    Folate receptor is overexpressed on the activated (but not quiescent) macrophages in both animal models and human patients with naturally occurring rheumatoid arthritis. The aim of this study was to prepare folate targeted poly(ethylene glycol) (PEG) conjugates of anionic dendrimer (G3.5 PAMAM) as targeted drug delivery systems to inflammation and to investigate its biodistribution pattern in arthritic rats. Folate-PEG-PAMAM conjugates, with different degrees of substitution were synthesized by a two-step reaction through a carbodiimide-mediated coupling reaction and loaded with indomethacin. Folate-PEG conjugation increased the drug loading efficiency by 10- to 20-fold and the in vitro release profile indicated controlled release of drug. The plasma pharmacokinetic parameters indicated an increased AUC, circulatory half-life and mean residence time for the folate-PEG conjugates. The tissue distribution studies revealed significantly lesser uptake by stomach for the folate-PEG conjugates, thereby limiting gastric-related side effect. The time-averaged relative drug exposure (r(e)) of the drug in paw for the folate-PEG conjugates ranged from 1.81 to 2.37. The overall drug targeting efficiency (T(e)) was highest for folate-PEG conjugate (3.44) when compared to native dendrimer (1.72). The folate-PEG-PAMAM conjugates are the ideal choice for targeted delivery of antiarthritic drugs to inflammation with reduced side-effects and higher targeting efficiency. Copyright 2007 Wiley Periodicals, Inc.

  10. Mono(pyridine-N-oxide) DOTA analog and its G1/G4-PAMAM dendrimer conjugates labeled with 177Lu: Radiolabeling and biodistribution studies

    International Nuclear Information System (INIS)

    Laznickova, A.; Biricova, V.; Laznicek, M.; Hermann, P.

    2014-01-01

    177 Lu radiolabeling of the first (G1-) or fourth (G4-) generation polyaminoamide (PAMAM) dendrimer conjugates with DOTA-like bifunctional chelator with one methylenepyridine-N-oxide pendant arm (DO3A-py NO-C ) stability of the radiolabeled species and their pharmacokinetic characteristics were evaluated in preclinical experiments. The results showed that the G1- and G4-dendrimer conjugates, modified in average with 7.5 or 57 DO3A-py NO-C chelating units, respectively, can also be labeled with 177 Lu with a high specific activity and radiochemical purity even at 37 °C. The radiolabeled species were stable for at least 24 h. Distribution profile of G1-dendrimer conjugate in organs and tissues of rats was more favorable than that of G4 one. On the other hand, the later dendrimer conjugate bears a substantially higher number of metal chelators per molecule enabling binding of a considerably larger number of radiometals. Our results indicate that an employment of dendrimer-chelate conjugates with bound radiometals might represent a prospective way for radiolabeling of biologically active target-specific macromolecules to obtain markedly high specific activity. - Highlights: • Chelation of DOTA-like ligands suitable for biomacromolecules modification. • Radiolabeling of modified PAMAM-dendrimers with 177 Lu. • Determination of stability of the labeled conjugates. • Pharmacokinetic characteristics evaluated in preclinical experiments

  11. In vitro evaluation of dendrimer prodrugs for oral drug delivery.

    Science.gov (United States)

    Najlah, Mohammad; Freeman, Sally; Attwood, David; D'Emanuele, Antony

    2007-05-04

    Dendrimer-based prodrugs were used to enhance the transepithelial permeability of naproxen, a low solubility model drug. The stability of the dendrimer-naproxen link was assessed. Naproxen was conjugated to G0 polyamidoamine (PAMAM) dendrimers either by an amide bond or an ester bond. The stability of G0 prodrugs was evaluated in 80% human plasma and 50% rat liver homogenate. The cytotoxicity of conjugates towards Caco-2 cells was determined and the transport of the conjugates across Caco-2 monolayers (37 degrees C) was reported. In addition, one lauroyl chain (L) was attached to the surface group of G0 PAMAM dendrimer of the diethylene glycol ester conjugate (G0-deg-NAP) to enhance permeability. The lactic ester conjugate, G0-lact-NAP, hydrolyzed slowly in 80% human plasma and in 50% rat liver homogenate (t(1/2)=180 min). G0-deg-NAP was hydrolyzed more rapidly in 80% human plasma (t(1/2)=51 min) and was rapidly cleaved in 50% liver homogenate (t(1/2)=4.7 min). The conjugates were non-toxic when exposed to Caco-2 cells for 3h. Permeability studies showed a significant enhancement in the transport of naproxen when conjugated to dendrimers; L-G0-deg-NAP yielding the highest permeability. Dendrimer-based prodrugs with appropriate linkers have potential as carriers for the oral delivery of low solubility drugs such as naproxen.

  12. Cellular uptake of glucoheptoamidated poly(amidoamine) PAMAM G3 dendrimer with amide-conjugated biotin, a potential carrier of anticancer drugs.

    Science.gov (United States)

    Uram, Łukasz; Szuster, Magdalena; Filipowicz, Aleksandra; Zaręba, Magdalena; Wałajtys-Rode, Elżbieta; Wołowiec, Stanisław

    2017-01-15

    In search for soluble derivatives of PAMAM dendrimers as potential carriers for hydrophobic drugs, the conjugates of PAMAM G3 with biotin, further converted into glycodendrimer with d-glucoheptono-1,4-lactone, were prepared. Polyamidoamine dendrimer (PAMAM) of third generation, G3 was functionalized with four biotin equivalents covalently attached to terminal amine nitrogens via amide bond G3 4B . The remaining 28 amine groups were blocked by glucoheptoamide substituents (gh) to give G3 4B28gh or with one fluorescein equivalent (attached by reaction of G3 4B with fluorescein isothiocyanate, FITC) via thiourea bond as FITC followed by exhaustive glucoheptoamidation to get G3 4B27gh1F . As a control the G3 substituted totally with 32 glucoheptoamide residues, G3 gh and its fluorescein labeled analogue G3 31gh1F were synthesized. The glucoheptoamidation of PAMAM G0 dendrimer with glucoheptono-1,4-lactone was performed in order to fully characterize the 1 H NMR spectra of glucoheptoamidated PAMAM dendrimers and to control the derivatization of G3 with glucoheptono-1,4-lactone. Another two derivatives of G3, namely G3 4B28gh1F' and G3 32ghF' , with ester bonded fluorescein were also obtained. Biological properties of obtained dendrimer conjugates were estimated in vitro with human cell lines: normal fibroblast (BJ) and two cancer glioblastoma (U-118 MG) and squamous carcinoma (SCC-15), including cytotoxicity by reduction of XTT and neutral red (NR) assays. Cellular uptake of dendrimer conjugates was evaluated with confocal microscopy. Obtained results confirmed, that biotinylated bioconjugates have always lower cytotoxicity and 3-4 times higher cellular uptake than non-biotinylated dendrimer conjugates in all cell lines. Comparison of various cell lines revealed different dose-dependent cell responses and the lower cytotoxicity of examined dendrimer conjugates for normal fibroblasts and squamous carcinoma, as compared with much higher cytotoxic effects seen in

  13. Peptide dendrimer-conjugates of ketoprofen: Synthesis and ex vivo and in vivo evaluations of passive diffusion, sonophoresis and iontophoresis for skin delivery.

    Science.gov (United States)

    Hegde, Aswathi R; Rewatkar, Prarthana V; Manikkath, Jyothsna; Tupally, Karnaker; Parekh, Harendra S; Mutalik, Srinivas

    2017-05-01

    The aim of this study was to evaluate skin delivery of ketoprofen when covalently tethered to mildly cationic (2 + or 4 + ) peptide dendrimers prepared wholly by solid phase peptide synthesis. The amino acids glycine, arginine and lysine formed the dendrimer with ketoprofen tethered either to the lysine side-arm (N ε ) or periphery of dendrimeric branches. Passive diffusion, sonophoresis- and iontophoresis-assisted permeation of each peptide dendrimer-drug conjugate (D1-D4) was studied across mouse skin, both in vitro and in vivo. In addition, skin toxicity of dendrimeric conjugates when trialed with iontophoresis or sonophoresis was also evaluated. All dendrimeric conjugates improved aqueous solubility at least 5-fold, compared to ketoprofen alone, while also exhibiting appreciable lipophilicity. In vitro passive diffusion studies revealed that ketoprofen in its native form was delivered to a greater extent, compared with a dendrimer-conjugated form at the end of 24h (Q 24h (μg/cm 2 ): ketoprofen (68.06±3.62)>D2 (49.62±2.92)>D4 (19.20±0.89)>D1 (6.45±0.40)>D3 (2.21±0.19). However, sonophoresis substantially increased the skin permeation of ketoprofen-dendrimer conjugates in 30min (Q 30min (μg/cm 2 ): D4 (122.19±7.14)>D2 (66.74±3.86)>D1 (52.10±3.22)>D3 (41.66±3.22)) although ketoprofen alone again proved superior (Q 30min : 167.99±9.11μg/cm 2 ). Next, application of iontophoresis was trialed and shown to considerably increase permeation of dendrimeric ketoprofen in 6h (Q 6h (μg/cm 2 ): D2 (711.49±39.14)>D4 (341.23±16.43)>D3 (89.50±4.99)>D1 (50.91±2.98), with a Q 6h value of 96.60±5.12μg/cm 2 for ketoprofen alone). In vivo studies indicated that therapeutically relevant concentrations of ketoprofen could be delivered transdermally when iontophoresis was paired with D2 (985.49±43.25ng/mL). Further, histopathological analysis showed that the dendrimeric approach was a safe mode as ketoprofen alone. The present study successfully demonstrates that

  14. Upregulation of ER signaling as an adaptive mechanism of cell survival in HER2-positive breast tumors treated with anti-HER2 therapy

    Science.gov (United States)

    Giuliano, Mario; Hu, Huizhong; Wang, Yen-Chao; Fu, Xiaoyong; Nardone, Agostina; Herrera, Sabrina; Mao, Sufeng; Contreras, Alejandro; Gutierrez, Carolina; Wang, Tao; Hilsenbeck, Susan G.; De Angelis, Carmine; Wang, Nicholas J.; Heiser, Laura M.; Gray, Joe W.; Lopez-Tarruella, Sara; Pavlick, Anne C.; Trivedi, Meghana V.; Chamness, Gary C.; Chang, Jenny C.; Osborne, C. Kent; Rimawi, Mothaffar F.; Schiff, Rachel

    2015-01-01

    Purpose To investigate the direct effect and therapeutic consequences of epidermal growth factor receptor 2 (HER2)-targeting therapy on expression of estrogen receptor (ER) and Bcl2 in preclinical models and clinical tumor samples. Experimental design Archived xenograft tumors from two preclinical models (UACC812 and MCF7/HER2-18) treated with ER and HER2-targeting therapies, and also HER2+ clinical breast cancer specimens collected in a lapatinib neoadjuvant trial (baseline and week 2 post treatment), were used. Expression levels of ER and Bcl2 were evaluated by immunohistochemistry and western blot. The effects of Bcl2 and ER inhibition, by ABT-737 and fulvestrant respectively, were tested in parental versus lapatinib-resistant UACC812 cells in vitro. Results Expression of ER and Bcl2 was significantly increased in xenograft tumors with acquired resistance to anti-HER2 therapy, compared with untreated tumors, in both preclinical models (UACC812: ER p=0.0014; Bcl2 p<0.001. MCF7/HER2-18: ER p=0.0007; Bcl2 p=0.0306). In the neoadjuvant clinical study, lapatinib treatment for two weeks was associated with parallel upregulation of ER and Bcl2 (Spearman’s coefficient: 0.70; p=0.0002). Importantly, 18% of tumors originally ER-negative (ER−) converted to ER+ upon anti-HER2 therapy. In ER−/HER2+ MCF7/HER2-18 xenografts, ER re-expression was primarily observed in tumors responding to potent combination of anti-HER2 drugs. Estrogen deprivation added to this anti-HER2 regimen significantly delayed tumor progression (p=0.018). In the UACC812 cells, fulvestrant, but not ABT-737, was able to completely inhibit anti-HER2-resistant growth (p<0.0001). Conclusion HER2 inhibition can enhance or restore ER expression with parallel Bcl2 upregulation, representing an ER-dependent survival mechanism potentially leading to anti-HER2 resistance. PMID:26015514

  15. Arginine–glycine–aspartic acid–polyethylene glycol–polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture

    Directory of Open Access Journals (Sweden)

    Chen Z

    2016-08-01

    Full Text Available Zhanfei Chen,1,* Fen Lian,1,* Xiaoqian Wang,1 Yanling Chen,1,2 Nanhong Tang1,2 1Fujian Institute of Hepatobiliary Surgery, Fujian Medical University Union Hospital, 2Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Research Center for Molecular Medicine, Fujian Medical University, Fuzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The polyamidoamine (PAMAM dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine–glycine–aspartic acid (RGD peptide. Our studies demonstrate that RGD–polyethylene glycol (PEG–PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT–MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. Keywords: dendrimer, arginine–glycine–aspartic acid (RGD, liver cell, spheroid culture, ammonia metabolism

  16. Developing Anti-HER2 Vaccines: Breast Cancer Experience.

    Science.gov (United States)

    Al-Awadhi, Aydah; Murray, James Lee; Ibrahim, Nuhad K

    2018-04-25

    Breast cancer accounts for more than one million new cases annually and is the leading cause of death in women globally. HER2 overexpression induces cellular and humoral immune responses against the HER2 protein and is associated with higher tumour proliferation rates. Trastuzumab-based therapies are effectively and widely used as standard of care in HER2-amplified/overexpressed breast cancer patients; one cited mechanism of action is the induction of passive immunity and antibody-dependent cellular cytotoxicity against malignant breast cancer cells. These findings drove the efforts to generate antigen-specific immunotherapy to trigger the patient's immune system to target HER2-overexpressing tumour cells, which led to the development of various vaccines against the HER2 antigen. This manuscript discusses the various anti-HER2 vaccine formulations and strategies and their potential role in the metastatic and adjuvant settings. This article is protected by copyright. All rights reserved. © 2018 UICC.

  17. Targeted delivery of doxorubicin-utilizing chitosan nanoparticles surface-functionalized with anti-Her2 trastuzumab

    Directory of Open Access Journals (Sweden)

    Yousefpour P

    2011-09-01

    selective uptake of CS-DOX-mAb by Her2+ cancer cells compared with nontargeted CS-DOX nanoparticles and free drug.Conclusion: Antibody-conjugated nanoparticles were shown to discriminate between Her2+ and Her2- cells, and thus have the potential to be used in active targeted drug delivery, with reduction of drug side effects in Her2+ breast and ovarian cancers.Keywords: chitosan, doxorubicin, self-assembled nanoparticles, active targeting, trastuzumab

  18. Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity.

    Science.gov (United States)

    Jevprasesphant, Rachaneekorn; Penny, Jeffrey; Attwood, David; McKeown, Neil B; D'Emanuele, Antony

    2003-10-01

    To evaluate the cytotoxicity, permeation, and transport mechanisms of PAMAM dendrimers and surface-modified cationic PAMAM dendrimers using monolayers of the human colon adenocarcinoma cell line, Caco-2. Cytotoxicity was determined using the MTT assay. The effect of dendrimers on monolayer integrity was determined from measurements of transepithelial electrical resistance (TEER) and [14C]mannitol apparent permeability coefficient (Papp). The Papp of dendrimers through monolayers was measured in both the apical (A)-to-basolateral (B) and B --> A directions at 4 degrees C and 37 degrees C and also in the presence and absence of ethylenediamine tetraacetic acid (EDTA) and colchicine. The cytotoxicity and permeation of dendrimers increased with both concentration and generation. The cytotoxicity of cationic dendrimers (G2, G3, G4) was greater than that of anionic dendrimers (G2.5, G3.5) but was reduced by conjugation with lauroyl chloride: the least cytotoxic conjugates were those with six attached lauroyl chains. At 37 degrees C the Papp of cationic dendrimers was higher than that of anionic dendrimers and, in general, increased with the number of attached lipid chains. Cationic dendrimers decreased TEER and significantly increased the Papp of mannitol. Modified dendrimers also reduced TEER and caused a more marked increase in the Papp of mannitol. The Papp values of dendrimers and modified dendrimers were higher in the presence of EDTA, lower in the presence of colchicine, and lower at 4 degrees C than at 37 degrees C. The properties of dendrimers may be significantly modified by surface engineering. Conjugation of cationic PAMAM dendrimers with lauroyl chloride decreased their cytotoxicity and increased their permeation through Caco-2 cell monolayers. Both PAMAM dendrimers and lauroyl-PAMAM dendrimer conjugates can cross epithelial monolayers by paracellular and transcellular pathways.

  19. Anti-HER2 CD4(+) T-helper type 1 response is a novel immune correlate to pathologic response following neoadjuvant therapy in HER2-positive breast cancer.

    Science.gov (United States)

    Datta, Jashodeep; Berk, Erik; Xu, Shuwen; Fitzpatrick, Elizabeth; Rosemblit, Cinthia; Lowenfeld, Lea; Goodman, Noah; Lewis, David A; Zhang, Paul J; Fisher, Carla; Roses, Robert E; DeMichele, Angela; Czerniecki, Brian J

    2015-05-23

    A progressive loss of circulating anti-human epidermal growth factor receptor-2/neu (HER2) CD4(+) T-helper type 1 (Th1) immune responses is observed in HER2(pos)-invasive breast cancer (IBC) patients relative to healthy controls. Pathologic complete response (pCR) following neoadjuvant trastuzumab and chemotherapy (T + C) is associated with decreased recurrence and improved prognosis. We examined differences in anti-HER2 Th1 responses between pCR and non-pCR patients to identify modifiable immune correlates to pathologic response following neoadjuvant T + C. Anti-HER2 Th1 responses in 87 HER2(pos)-IBC patients were examined using peripheral blood mononuclear cells pulsed with 6 HER2-derived class II peptides via IFN-γ ELISPOT. Th1 response metrics were anti-HER2 responsivity, repertoire (number of reactive peptides), and cumulative response across 6 peptides (spot-forming cells [SFC]/10(6) cells). Anti-HER2 Th1 responses of non-pCR patients (n = 4) receiving adjuvant HER2-pulsed type 1-polarized dendritic cell (DC1) vaccination were analyzed pre- and post-immunization. Depressed anti-HER2 Th1 responses observed in treatment-naïve HER2(pos)-IBC patients (n = 22) did not improve globally in T + C-treated HER2(pos)-IBC patients (n = 65). Compared with adjuvant T + C receipt, neoadjuvant T + C - utilized in 61.5 % - was associated with higher anti-HER2 Th1 repertoire (p = 0.048). While pCR (n = 16) and non-pCR (n = 24) patients did not differ substantially in demographic/clinical characteristics, pCR patients demonstrated dramatically higher anti-HER2 Th1 responsivity (94 % vs. 33 %, p = 0.0002), repertoire (3.3 vs. 0.3 peptides, p vs. 22.4 SFC/10(6), p non-pCR patients. After controlling for potential confounders, anti-HER2 Th1 responsivity remained independently associated with pathologic response (odds ratio 8.82, p = 0.016). This IFN-γ(+) immune disparity was mediated by anti-HER2 CD4(+)T-bet(+)IFN-γ(+) (i.e., Th1) - not CD4(+)GATA-3(+)IFN-γ(+) (i.e., Th2

  20. A molecular dynamics study of the structure and inter-particle interactions of polyethylene glycol-conjugated PAMAM dendrimers

    OpenAIRE

    Lee, Hwankyu; Larson, Ronald G.

    2009-01-01

    We performed molecular dynamics (MD) simulations of one or two copies of polyethylene glycol of molecular weight 550 (PEG550) and 5000 (PEG5000) Daltons, conjugated to generation 3 (G3) to 5 (G5) polyamidoamine (PAMAM) dendrimers with explicit water using a coarse-grained model. We found the radii of gyration of these dendrimer-PEG molecules to be close to those measured in experiments by Hedden and Bauer (Macromolecules 2003, 36, 1829). Densely grafted PEG ligands (>50% of the dendrimer surf...

  1. Comparative Evaluation of Anti-HER2 Affibody Molecules Labeled with 64Cu Using NOTA and NODAGA

    Directory of Open Access Journals (Sweden)

    Vladimir Tolmachev

    2017-01-01

    Full Text Available Imaging using affibody molecules enables discrimination between breast cancer metastases with high and low expression of HER2, making appropriate therapy selection possible. This study aimed to evaluate if the longer half-life of 64Cu (T1/2 = 12.7 h would make 64Cu a superior nuclide compared to 68Ga for PET imaging of HER2 expression using affibody molecules. The synthetic ZHER2:S1 affibody molecule was conjugated with the chelators NOTA or NODAGA and labeled with 64Cu. The tumor-targeting properties of 64Cu-NOTA-ZHER2:S1 and 64Cu-NODAGA-ZHER2:S1 were evaluated and compared with the targeting properties of 68Ga-NODAGA-ZHER2:S1 in mice. Both 64Cu-NOTA-ZHER2:S1 and 64Cu-NODAGA-ZHER2:S1 demonstrated specific targeting of HER2-expressing xenografts. At 2 h after injection of 64Cu-NOTA-ZHER2:S1, 64Cu-NODAGA-ZHER2:S1, and 68Ga-NODAGA-ZHER2:S1, tumor uptakes did not differ significantly. Renal uptake of 64Cu-labeled conjugates was dramatically reduced at 6 and 24 h after injection. Notably, radioactivity uptake concomitantly increased in blood, lung, liver, spleen, and intestines, which resulted in decreased tumor-to-organ ratios compared to 2 h postinjection. Organ uptake was lower for 64Cu-NODAGA-ZHER2:S1. The most probable explanation for this biodistribution pattern was the release and redistribution of renal radiometabolites. In conclusion, monoamide derivatives of NOTA and NODAGA may be suboptimal chelators for radiocopper labeling of anti-HER2 affibody molecules and, possibly, other scaffold proteins with high renal uptake.

  2. Synthesis and in-vitro cytotoxicity of dendrimer cytostatic conjugates

    OpenAIRE

    Scutaru, Ana Maria

    2011-01-01

    Bendamustine and melphalan are nitrogen mustard derivatives from the group of alkylating agents and are used for the treatment of various cancers such as chronic lymphocytic leukemia (CLL) or breast cancer. However their use is limited by numerous side effects. Therefore, 1,3,5-tris(3-aminopropyl)benzene (G0) and the G1 analogous 1,3,5-tris[3,5-bis(3-aminopropyl)-N-propylbenzamide]benzene were chosen to synthesize cytostatic-dendrimer conjugates and to achieve ‘tumor targeting' through the EP...

  3. Phosphorylcholine functionalized dendrimers for the formation of highly stable and reactive gold nanoparticles and their glucose conjugation for biosensing

    International Nuclear Information System (INIS)

    Jia Lan; Lv Liping; Xu Jianping; Ji Jian

    2011-01-01

    Phosphorylcholine (PC)-functionalized poly(amido amine) (PAMAM) dendrimers were prepared and used as both reducing and stabilizing agents for synthesis of highly stable and reactive gold nanoparticles (Au NPs). Biomimetic PC-functionalized PAMAM dendrimers-stabilized gold nanoparticles (Au DSNPs) were formed by simply mixing the PC modified amine-terminated fifth-generation PAMAM dendrimers (G5-PC) with AuCl 4 − ions by controlling the pH, no additional reducing agents or other stabilizers were needed. The obtained Au DSNPs were shown to be spherical, with particle diameters ranging from 5 to 12 nm, the sizes and growth kinetics of Au DSNPs could be tuned by changing the pH and the initial molar ratio of dendrimers to gold as indicated by transmission electron microscopy (TEM) and UV–Vis data. The prepared Au DSNPs showed excellent stability including: (1) stable at wide pH (7–13) values; (2) stable at high salt concentrations up to 2 M NaCl; (3) non-specific protein adsorption resistance. More importantly, surface functionalization could be performed by introducing desired functional groups onto the remained reactive amine groups. This was exemplified by the glucose conjugation. The glucose conjugated Au DSNPs showed bio-specific interaction with Concanavalin A (Con A), which induced aggregation of the Au NPs. Colorimetric detection of Con A based on the plasmon resonance of the glucose conjugated Au DSNPs was realized. A limit of detection (LOD) for Con A was 0.6 μM, based on a signal-to-noise ratio (S/N) of 3. These findings demonstrated that the PC modified Au DSNPs could potentially serve as a versatile nano-platform for the biomedical applications.

  4. Smart AS1411-aptamer conjugated pegylated PAMAM dendrimer for the superior delivery of camptothecin to colon adenocarcinoma in vitro and in vivo.

    Science.gov (United States)

    Alibolandi, Mona; Taghdisi, Seyed Mohammad; Ramezani, Pouria; Hosseini Shamili, Fazileh; Farzad, Sara Amel; Abnous, Khalil; Ramezani, Mohammad

    2017-03-15

    In the current study camptothecin-loaded pegylated PAMAM dendrimer were synthesized and were functionalized with AS1411 anti-nucleolin aptamers for site-specific targeting against colorectal cancer cells which over expresses nucleolin receptors. The morphological properties and size dispersity of the prepared nanoparticles were evaluated using transmission electron microscope (TEM) and DLS. The drug-loading content and encapsulation efficiency were obtained 8.1% and 93.67% respectively. The in vitro release of camptothecin from the formulation was provided the sustained release of encapsulated camptothecin during 4days. Comparative in vitro cytotoxicity experiments demonstrated that the targeted camptothecin loaded-pegylated dendrimers had higher antiproliferation activity, towards nucleolin-positive HT29 and C26 colorectal cancer cells than nucleolin-negative CHO cell line. Fluorscence microscopy and flow cytometry also confirmed the enhanced cellular uptake of AS1411 targeted pegylated-dendrimer. In vivo study in C26 tumor-bearing BALB/C mice revealed that the AS1411-functionalized camptothecin loaded pegylated dendrimers improved antitumor activity and survival rate of the encapsulated camptothecin. Conjugation of AS1411 aptamer to the camptothecin loaded-pegylated dendrimer surface provides site-specific delivery of camptothecin, inhibit C26 tumor growth in vivo and significantly decrease systemic toxicity. These results suggested that the new nucleolin-targeted pegylated PAMAM dendrimer as a delivery system for camptothecin have the potential for the treatment of nucleolin-overexpressed colorectal cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Novel anti-HER2 monoclonal antibodies: synergy and antagonism with tumor necrosis factor-α

    Directory of Open Access Journals (Sweden)

    Ceran Ceyhan

    2012-10-01

    Full Text Available Abstract Background One-third of breast cancers display amplifications of the ERBB2 gene encoding the HER2 kinase receptor. Trastuzumab, a humanized antibody directed against an epitope on subdomain IV of the extracellular domain of HER2 is used for therapy of HER2-overexpressing mammary tumors. However, many tumors are either natively resistant or acquire resistance against Trastuzumab. Antibodies directed to different epitopes on the extracellular domain of HER2 are promising candidates for replacement or combinatorial therapy. For example, Pertuzumab that binds to subdomain II of HER2 extracellular domain and inhibits receptor dimerization is under clinical trial. Alternative antibodies directed to novel HER2 epitopes may serve as additional tools for breast cancer therapy. Our aim was to generate novel anti-HER2 monoclonal antibodies inhibiting the growth of breast cancer cells, either alone or in combination with tumor necrosis factor-α (TNF-α. Methods Mice were immunized against SK-BR-3 cells and recombinant HER2 extracellular domain protein to produce monoclonal antibodies. Anti-HER2 antibodies were characterized with breast cancer cell lines using immunofluorescence, flow cytometry, immunoprecipitation, western blot techniques. Antibody epitopes were localized using plasmids encoding recombinant HER2 protein variants. Antibodies, either alone or in combination with TNF-α, were tested for their effects on breast cancer cell proliferation. Results We produced five new anti-HER2 monoclonal antibodies, all directed against conformational epitope or epitopes restricted to the native form of the extracellular domain. When tested alone, some antibodies inhibited modestly but significantly the growth of SK-BR-3, BT-474 and MDA-MB-361 cells displaying ERBB2 amplification. They had no detectable effect on MCF-7 and T47D cells lacking ERBB2 amplification. When tested in combination with TNF-α, antibodies acted synergistically on SK-BR-3 cells

  6. Molecular dynamics study of the structure and interparticle interactions of polyethylene glycol-conjugated PAMAM dendrimers.

    Science.gov (United States)

    Lee, Hwankyu; Larson, Ronald G

    2009-10-08

    We performed molecular dynamics (MD) simulations of one or two copies of polyethylene glycol of molecular weight 550 (PEG550) and 5000 (PEG5000) daltons, conjugated to generation 3 (G3) to 5 (G5) polyamidoamine (PAMAM) dendrimers with explicit water using a coarse-grained model. We found the radii of gyration of these dendrimer-PEG molecules to be close to those measured in experiments by Hedden and Bauer (Hedden , R. C. ; Bauer , B. J. Macromolecules 2003 , 36 , 1829.). Densely grafted PEG ligands (>50% of the dendrimer surface) extend like brushes, with layer thickness in agreement with theory for starlike polymers. Two dendrimer-PEG complexes in the box drift away from each other, indicating that no aggregation is induced by either short or long PEG chains, conflicting with a recent view that the cytotoxicity of some PEGylated particles might be due to particle aggregation for long PEG lengths.

  7. Interaction studies reveal specific recognition of an anti-inflammatory polyphosphorhydrazone dendrimer by human monocytes.

    Science.gov (United States)

    Ledall, Jérémy; Fruchon, Séverine; Garzoni, Matteo; Pavan, Giovanni M; Caminade, Anne-Marie; Turrin, Cédric-Olivier; Blanzat, Muriel; Poupot, Rémy

    2015-11-14

    Dendrimers are nano-materials with perfectly defined structure and size, and multivalency properties that confer substantial advantages for biomedical applications. Previous work has shown that phosphorus-based polyphosphorhydrazone (PPH) dendrimers capped with azabisphosphonate (ABP) end groups have immuno-modulatory and anti-inflammatory properties leading to efficient therapeutic control of inflammatory diseases in animal models. These properties are mainly prompted through activation of monocytes. Here, we disclose new insights into the molecular mechanisms underlying the anti-inflammatory activation of human monocytes by ABP-capped PPH dendrimers. Following an interdisciplinary approach, we have characterized the physicochemical and biological behavior of the lead ABP dendrimer with model and cell membranes, and compared this experimental set of data to predictive computational modelling studies. The behavior of the ABP dendrimer was compared to the one of an isosteric analog dendrimer capped with twelve azabiscarboxylate (ABC) end groups instead of twelve ABP end groups. The ABC dendrimer displayed no biological activity on human monocytes, therefore it was considered as a negative control. In detail, we show that the ABP dendrimer can bind both non-specifically and specifically to the membrane of human monocytes. The specific binding leads to the internalization of the ABP dendrimer by human monocytes. On the contrary, the ABC dendrimer only interacts non-specifically with human monocytes and is not internalized. These data indicate that the bioactive ABP dendrimer is recognized by specific receptor(s) at the surface of human monocytes.

  8. Delivery of paclitaxel across cellular barriers using a dendrimer-based nanocarrier.

    Science.gov (United States)

    Teow, Huey Minn; Zhou, Zhengyuan; Najlah, Mohammad; Yusof, Siti R; Abbott, N Joan; D'Emanuele, Antony

    2013-01-30

    The aim of this study was to investigate the ability of a third-generation (G3) polyamidoamine (PAMAM) dendrimer-based carrier to enhance the permeability of paclitaxel (pac) and to overcome cellular barriers. G3 dendrimers were surface modified with lauryl chains (L) and conjugated with paclitaxel (pac) via a glutaric anhydride (glu) linker, followed by labeling with FITC. Biological evaluation of the dendrimer and conjugates was conducted using the human colon adenocarcinoma cell line (Caco-2) and primary cultured porcine brain endothelial cells (PBECs). LDH assay was used to evaluate the cytotoxicity of the dendrimer and conjugates. Cytotoxicity studies showed that the conjugation of lauryl chains and paclitaxel on G3 dendrimer significantly (pdendrimer-drug conjugates demonstrated an increase in the apparent permeability coefficient (P(app)) in both apical to basolateral A→B and basolateral to apical B→A directions across both cell monolayers compared to unmodified G3 and free drug. The B→A P(app) of paclitaxel was significantly (ptransporter system in both cell models. L6-G3-glu-pac conjugate had approximately 12-fold greater permeability across both cell monolayers than that of paclitaxel alone. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Development of an Anti-HER2 Monoclonal Antibody H2Mab-139 Against Colon Cancer.

    Science.gov (United States)

    Kaneko, Mika K; Yamada, Shinji; Itai, Shunsuke; Kato, Yukinari

    2018-02-01

    Human epidermal growth factor receptor 2 (HER2) expression has been reported in several cancers, such as breast, gastric, lung, pancreatic, and colorectal cancers. HER2 is overexpressed in those cancers and is associated with poor clinical outcomes. Trastuzumab, a humanized anti-HER2 antibody, provides significant survival benefits for patients with HER2-overexpressing breast cancers and gastric cancers. In this study, we developed a novel anti-HER2 monoclonal antibody (mAb), H 2 Mab-139 (IgG 1 , kappa) and investigated it against colon cancers using flow cytometry, western blot, and immunohistochemical analyses. Flow cytometry analysis revealed that H 2 Mab-139 reacted with colon cancer cell lines, such as Caco-2, HCT-116, HCT-15, HT-29, LS 174T, COLO 201, COLO 205, HCT-8, SW1116, and DLD-1. Although H 2 Mab-139 strongly reacted with LN229/HER2 cells on the western blot, we did not observe a specific signal for HER2 in colon cancer cell lines. Immunohistochemical analyses revealed sensitive and specific reactions of H 2 Mab-139 against colon cancers, indicating that H 2 Mab-139 is useful in detecting HER2 overexpression in colon cancers using flow cytometry and immunohistochemical analyses.

  10. HER2-positive breast cancer, how far away from the cure?-on the current situation of anti-HER2 therapy in breast cancer treatment and survival of patients.

    Science.gov (United States)

    Liao, Ning

    2016-06-01

    With the diagnosis and treatment of tumor enter into the area of precision medical, based on selected targeted molecular typing of patients with individualized diagnosis and treatment play an important role. HER gene encoded epidermal growth factor receptor 2 (HER2) leading to increased early distant metastasis of breast cancer in patients and poor prognosis. However, a number of clinical studies provided evidence-based anti-HER2 targeted therapy and confirmed the benefit of anti-HER2 targeted therapy in patient survival. In recent years, through the tireless efforts of scholars in the field of breast cancer in our country, the whole diagnosis and treatment of breast cancer has accomplished an international standard. But based on a variety of factors, the anti-HER2 targeted therapy between China and the developed countries, and between different areas in China still exists certain gaps, is now a problem need to be solved. This article will analyzing the diagnostic and treatment on HER2-positive breast cancer in the United States and China, exploring reasons and looking for answers to narrow down the gap in the treatment of HER2-positive breast cancer between China and the United States. Improve the anti-HER2 targeted therapy in our country, let the patients get maximum benefit from anti-HER2 targeted therapy.

  11. Combination therapies for the treatment of HER2-positive breast cancer: current and future prospects.

    Science.gov (United States)

    Brandão, Mariana; Pondé, Noam F; Poggio, Francesca; Kotecki, Nuria; Salis, Mauren; Lambertini, Matteo; de Azambuja, Evandro

    2018-05-24

    HER2-positive disease is an aggressive subtype of breast cancer that has been revolutionized by anti-HER2 directed therapies. Multiple drugs have been developed and are currently in clinical use, including trastuzumab, lapatinib, pertuzumab, T-DM1, and neratinib, alone or combined in 'dual HER2-blockade' regimens. Areas covered: A comprehensive literature review was performed regarding the current state and the future of combination regimens containing anti-HER2 agents, focusing on their efficacy, toxicity, and cost-effectiveness. Expert commentary: The combination of trastuzumab/pertuzumab is approved in all disease settings, while trastuzumab/neratinib is approved in the adjuvant setting and trastuzumab/lapatinib in metastatic disease. Meanwhile, as breast cancer biology and resistance mechanisms become clearer, combinations with drugs like PI3K/Akt/mTOR inhibitors, CDK4/6 inhibitors, anti-PD(L)1 antibodies, endocrine therapy, and new anti-HER2 agents (panHER and HER2 tyrosine kinase inhibitors, bispecific antibodies, anti-HER3 antibodies, and antibody-drug conjugates) are being extensively tested in clinical trials. More specific strategies for the 'triple-positive' (estrogen receptor-positive/HER2-positive) disease are also being explored. However, there is an urgent need for the development of predictive biomarkers for a better tailoring of anti-HER2 directed therapy. This is the only way to further improve clinical outcomes and quality of life and to decrease costs and toxicities of unnecessary treatments.

  12. Dual stimuli-sensitive dendrimers: Photothermogenic gold nanoparticle-loaded thermo-responsive elastin-mimetic dendrimers.

    Science.gov (United States)

    Fukushima, Daichi; Sk, Ugir Hossain; Sakamoto, Yasuhiro; Nakase, Ikuhiko; Kojima, Chie

    2015-08-01

    Dendrimers are synthetic macromolecules with unique structures that can work as nanoplatforms for both photothermogenic gold nanoparticles (AuNPs) and thermosensitive elastin-like peptides (ELPs) with valine-proline-glycine-valine-glycine (VPGVG) repeats. In this study, photothermogenic AuNPs were loaded into thermo-responsive elastin-mimetic dendrimers (dendrimers conjugating ELPs at their periphery) to produce dual stimuli-sensitive nanoparticles. Polyamidoamine G4 dendrimers were modified with acetylated VPGVG and (VPGVG)2, and the resulting materials were named ELP1-den and ELP2-den, respectively. The AuNPs were prepared by the reduction of Au ions using a dendrimer-nanotemplated method. The AuNP-loaded elastin-mimetic dendrimers exhibited photothermal properties. ELP1-den and ELP2-den showed similar temperature-dependent changes in their conformations. Phase transitions were observed at around 55°C and 35°C for the AuNP-loaded ELP1-den and AuNP-loaded ELP2-den, respectively, but not for the corresponding PEGylated dendrimer. In contrast to the AuNP-loaded PEGylated dendrimer, AuNP-loaded ELP2-den readily associated with cells and induced efficient photocytotoxicity at 37°C. The cell association and the photocytotoxicity properties of AuNP-loaded ELP2-den could be controlled by temperature. These results therefore suggest that dual stimuli-sensitive dendrimer nanoparticles of this type could be used for photothermal therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. G3.5 PAMAM dendrimers enhance transepithelial transport of SN38 while minimizing gastrointestinal toxicity.

    Science.gov (United States)

    Goldberg, Deborah S; Vijayalakshmi, Nirmalkumar; Swaan, Peter W; Ghandehari, Hamidreza

    2011-03-30

    Poly(amido amine) (PAMAM) dendrimers have shown promise in oral drug delivery. Conjugation of SN38 to PAMAM dendrimers has the potential to improve its oral absorption while minimizing gastrointestinal toxicity. In this work we evaluated G3.5 PAMAM dendrimer-SN38 conjugates with ester-linked glycine and β-alanine spacers for their suitability in oral therapy of hepatic colorectal cancer metastases. G3.5-βAlanine-SN38 was mostly stable while G3.5-Glycine-SN38 showed 10%, 20%, and 56% SN38 release in simulated gastric, intestinal and liver environments for up to 6, 24 and 48 hours, respectively. Short-term treatment of Caco-2 cells with G3.5-SN38 conjugates did not reduce cell viability, while comparable concentrations of SN38 caused significant cytotoxicity. G3.5-Glycine-SN38 and G3.5-βAlanine-SN38 showed IC₅₀ values of 0.60 and 3.59 μM, respectively, in HT-29 cells treated for 48 h, indicating the efficacy of the drug delivery system in colorectal cancer cells with longer incubation time. Both conjugates increased SN38 transepithelial transport compared to the free drug. Transport of G3.5-Glycine-SN38 was highly concentration-dependent whereas transport of G3.5-βAlanine-SN38 was concentration-independent, highlighting the influence of drug loading and spacer chemistry on transport mechanism. Together these results show that PAMAM dendrimers have the potential to improve the oral bioavailability of potent anti-cancer drugs. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Transepithelial transport of PEGylated anionic poly(amidoamine) dendrimers: implications for oral drug delivery.

    Science.gov (United States)

    Sweet, Deborah M; Kolhatkar, Rohit B; Ray, Abhijit; Swaan, Peter; Ghandehari, Hamidreza

    2009-08-19

    The purpose of this work was to assess the impact of PEGylation on transepithelial transport of anionic poly(amidoamine) dendrimers. Cytotoxicity, uptake and transport across Caco-2 cells of PEGylated G3.5 and G4.5 PAMAM dendrimers were studied. Methoxy polyethylene glycol (750 Da) was conjugated to carboxylic acid-terminated PAMAM dendrimers at feed ratios of 1, 2 and 4 PEG per dendrimer. Compared to the control, PEGylation of anionic dendrimers did not significantly alter cytotoxicity up to a concentration of 0.1 mM. PEGylation of G3.5 dendrimers significantly decreased cellular uptake and transepithelial transport while PEGylation of G4.5 dendrimers led to a significant increase in uptake, but also a significant decrease in transport. Dendrimer PEGylation reduced the opening of tight junctions as evidenced by confocal microscopy techniques. Modulation of the tight junctional complex correlated well with changes in PEGylated dendrimer transport and suggests that anionic dendrimers are transported primarily through the paracellular route. PEGylated dendrimers show promise in oral delivery applications where increased functionality for drug conjugation and release is desired.

  15. Development and Characterization of a Humanized Anti-HER2 Antibody HuA21 with Potent Anti-Tumor Properties in Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ruilin Li

    2016-04-01

    Full Text Available Human epidermal growth factor receptor 2 (HER2 is one of the most studied tumor-associated antigens for cancer immunotherapy. An engineered anti-HER-2 chimeric A21 antibody (chA21 is a chimeric antibody targeted to subdomain I of the HER2 extracellular domain. Here, we report the anti-tumor activity of the novel engineered monoclonal antibody humanized chA21 (HuA21 that targets HER2 on the basis of chA21, and we describe the underlying mechanisms. Our results reveal that HuA21 markedly inhibits the proliferation and migration of HER2-overexpressing breast cancer cells and causes enhanced antibody-dependent cell-mediated cytotoxicity potency against HER2-overexpressing tumor cells. In particular, HuA21, but not trastuzumab (Tra, markedly suppresses growth and enhances the internalization of the antibody in Tra-resistant BT-474 breast cancer cells. These characteristics are highly associated with the intrinsic ability of HuA21 to down-regulate HER2 activation and inhibit the extracellular signal-regulated kinase 1/2 (ERK1/2 and protein kinase B (Akt signaling pathways. Furthermore, the combination of HuA21 with Tra synergistically enhances the anti-tumor effects in vitro and in vivo and inhibits HER2 activation and the ERK1/2 and Akt signaling pathways. Altogether, our results suggest that HuA21 may represent a unique anti-HER2 antibody with potential as a therapeutic candidate alone or in combination with other anti-HER2 reagents in cancer therapy.

  16. H2Mab-77 is a Sensitive and Specific Anti-HER2 Monoclonal Antibody Against Breast Cancer.

    Science.gov (United States)

    Itai, Shunsuke; Fujii, Yuki; Kaneko, Mika K; Yamada, Shinji; Nakamura, Takuro; Yanaka, Miyuki; Saidoh, Noriko; Chang, Yao-Wen; Handa, Saori; Takahashi, Maki; Suzuki, Hiroyoshi; Harada, Hiroyuki; Kato, Yukinari

    2017-08-01

    Human epidermal growth factor receptor 2 (HER2) plays a critical role in the progression of breast cancers, and HER2 overexpression is associated with poor clinical outcomes. Trastuzumab is an anti-HER2 humanized antibody that leads to significant survival benefits in patients with HER2-positive metastatic breast cancers. In this study, we developed novel anti-HER2 monoclonal antibodies (mAbs) and characterized their efficacy in flow cytometry, Western blot, and immunohistochemical analyses. Initially, we expressed the full length or ectodomain of HER2 in LN229 glioblastoma cells and then immunized mice with ectodomain of HER2 or LN229/HER2, and performed the first screening by enzyme-linked immunosorbent assays using ectodomain of HER2. Subsequently, we selected mAbs according to their efficacy in flow cytometry (second screening), Western blot (third screening), and immunohistochemical analyses (fourth screening). Among 100 mAb clones, only three mAbs reacted with HER2 in Western blot, and clone H 2 Mab-77 (IgG 1 , kappa) was selected. Finally, immunohistochemical analyses with H 2 Mab-77 showed sensitive and specific reactions against breast cancer cells, warranting the use of H 2 Mab-77 to detect HER2 in pathological analyses of breast cancers.

  17. Near-infrared quantum dots for HER2 localization and imaging of cancer cells.

    Science.gov (United States)

    Rizvi, Sarwat B; Rouhi, Sepideh; Taniguchi, Shohei; Yang, Shi Yu; Green, Mark; Keshtgar, Mo; Seifalian, Alexander M

    2014-01-01

    Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, particularly in medical and surgical oncology. Near-infrared-emitting quantum dots can be visualized in deep tissues because the biological window is transparent to these wavelengths. Their small sizes and free surface reactive groups that can be conjugated to biomolecules make them ideal probes for in vivo cancer localization, targeted chemotherapy, and image-guided cancer surgery. The human epidermal growth factor receptor 2 gene (HER2/neu) is overexpressed in 25%-30% of breast cancers. The current methods of detection for HER2 status, including immunohistochemistry and fluorescence in situ hybridization, are used ex vivo and cannot be used in vivo. In this paper, we demonstrate the application of near-infrared-emitting quantum dots for HER2 localization in fixed and live cancer cells as a first step prior to their in vivo application. Near-infrared-emitting quantum dots were characterized and their in vitro toxicity was established using three cancer cell lines, ie, HepG2, SK-BR-3 (HER2-overexpressing), and MCF7 (HER2-underexpressing). Mouse antihuman anti-HER2 monoclonal antibody was conjugated to the near-infrared-emitting quantum dots. In vitro toxicity studies showed biocompatibility of SK-BR-3 and MCF7 cell lines with near-infrared-emitting quantum dots at a concentration of 60 μg/mL after one hour and 24 hours of exposure. Near-infrared-emitting quantum dot antiHER2-antibody bioconjugates successfully localized HER2 receptors on SK-BR-3 cells. Near-infrared-emitting quantum dot bioconjugates can be used for rapid localization of HER2 receptors and can potentially be used for targeted therapy as well as image-guided surgery.

  18. A Single Domain–Based Anti-Her2 Antibody Has Potent Antitumor Activities

    Directory of Open Access Journals (Sweden)

    Xiaoqiong Wu

    2018-04-01

    Full Text Available Human epidermal growth factor receptor 2 (HER2 is overexpressed in approximately 20% to 30% of breast cancers and various other types of cancers, which plays a vital role in the cancer progression. Monoclonal antibodies targeting Her2 are now used in the clinic to treat Her2 overexpression cancer patients. However, relapse or resistance is frequent with the current therapies. To generate a new treatment avenue against Her2, we immunized and selected a specific anti-Her2 single domain antibody C3 for further studies. The C3-Fc antibody drove antibody-dependent cell-mediated cytotoxicity against Her2-positive tumor cells in vitro and resulted in potent antitumor growth in vivo. These data suggest that the C3-Fc antibody may provide an alternative avenue for Her2-positive cancer therapy.

  19. Mechanism of gene transfection by polyamidoamine (PAMAM) dendrimers modified with ornithine residues.

    Science.gov (United States)

    Kumar, Ajay; Yellepeddi, Venkata K; Vangara, Kiran K; Strychar, Kevin B; Palakurthi, Srinath

    2011-11-01

    The aim of this study was to prepare and investigate the mechanism of uptake of the dendriplexes prepared with ornithine-conjugated polyamidoamine (PAMAM) G4 dendrimers. Ornithine-conjugated PAMAMG4 dendrimers were prepared by Fmoc synthesis. A comparative transfection study in NCI H157G cells and polyamine transport-deficient cell line NCI H157R was performed to confirm the role of the polyamine transporter system (PAT) in the dendriplex uptake. Transfection efficiency significantly increased with increase in generation number and extent of ornithine conjugation. Transfection efficiency of the PAMAMG4-ORN60 dendrimers significantly decreased in presence of excess of ornithine (P dendrimers. Transfection efficiency of PAMAMG4-ORN60 was significantly low in NCI H157R (31.66 ± 3.95%, RFU: 17.87 ± 1.34) as compared to NCI H157G cell line (63.07 ± 6.8%, relative fluorescence units (RFU): 23.28 ± 0.66). Results indicate the role of PAT in addition to charge-mediated endocytosis in the internalization of ornithine-conjugated PAMAMG4 dendrimers. Cytotoxicity analysis (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay) in human embryonic kidney cell line (HEK) 293T cells showed that the dendriplexes were non-toxic at N/P 10.

  20. P5 HER2/neu-derived peptide conjugated to liposomes containing MPL adjuvant as an effective prophylactic vaccine formulation for breast cancer.

    Science.gov (United States)

    Shariat, Sheida; Badiee, Ali; Jalali, Seyed Amir; Mansourian, Mercedeh; Yazdani, Mona; Mortazavi, Seyed Alireza; Jaafari, Mahmoud Reza

    2014-12-01

    Vaccines containing synthetic peptides derived from tumor-associated antigens (TAA) can elicit potent cytotoxic T lymphocyte (CTL) response if they are formulated in an optimal vaccine delivery system. The aim of this study was to develop a simple and effective lipid-based vaccine delivery system using P5 HER2/neu-derived peptide conjugated to Maleimide-PEG2000-DSPE. The conjugated lipid was then incorporated into liposomes composed of DMPC:DMPG:Chol:DOPE containing Monophosphoryl lipid A (MPL) (Lip-DOPE-P5-MPL). Different liposome formulations were prepared and characterized for their physicochemical properties. To evaluate anti-tumoral efficacy, BALB/c mice were immunized subcutaneously 3 times in two-week intervals and the generated immune response was studied. The results demonstrated that Lip-DOPE-P5-MPL induced a significantly higher IFN-γ production by CD8+ T cells intracellularly which represents higher CTL response in comparison with other control formulations. CTL response induced by this formulation caused the lowest tumor size and the longest survival time in a mice model of TUBO tumor. The encouraging results achieved by Lip-DOPE-P5-MPL formulation could make it a promising candidate in developing effective vaccines against Her2 positive breast cancers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. BRCAA1 antibody- and Her2 antibody-conjugated amphiphilic polymer engineered CdSe/ZnS quantum dots for targeted imaging of gastric cancer

    Science.gov (United States)

    Li, Chao; Ji, Yang; Wang, Can; Liang, Shujing; Pan, Fei; Zhang, Chunlei; Chen, Feng; Fu, Hualin; Wang, Kan; Cui, Daxiang

    2014-05-01

    Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.

  2. Developmental toxicity of low generation PAMAM dendrimers in zebrafish

    International Nuclear Information System (INIS)

    King Heiden, Tisha C.; Dengler, Emelyne; Kao, Weiyuan John; Heideman, Warren; Peterson, Richard E.

    2007-01-01

    Biological molecules and intracellular structures operate at the nanoscale; therefore, development of nanomedicines shows great promise for the treatment of disease by using targeted drug delivery and gene therapies. PAMAM dendrimers, which are highly branched polymers with low polydispersity and high functionality, provide an ideal architecture for construction of effective drug carriers, gene transfer devices and imaging of biological systems. For example, dendrimers bioconjugated with selective ligands such as Arg-Gly-Asp (RGD) would theoretically target cells that contain integrin receptors and show potential for use as drug delivery devices. While RGD-conjugated dendrimers are generally considered not to be cytotoxic, there currently exists little information on the risks that such materials pose to human health. In an effort to compliment and extend the knowledge gleaned from cell culture assays, we have used the zebrafish embryo as a rapid, medium throughput, cost-effective whole-animal model to provide a more comprehensive and predictive developmental toxicity screen for nanomaterials such as PAMAM dendrimers. Using the zebrafish embryo, we have assessed the developmental toxicity of low generation (G3.5 and G4) PAMAM dendrimers, as well as RGD-conjugated forms for comparison. Our results demonstrate that G4 dendrimers, which have amino functional groups, are toxic and attenuate growth and development of zebrafish embryos at sublethal concentrations; however, G3.5 dendrimers, with carboxylic acid terminal functional groups, are not toxic to zebrafish embryos. Furthermore, RGD-conjugated G4 dendrimers are less potent in causing embryo toxicity than G4 dendrimers. RGD-conjugated G3.5 dendrimers do not elicit toxicity at the highest concentrations tested and warrant further study for use as a drug delivery device

  3. Improved tumor targeting of anti-HER2 nanobody through N-succinimidyl 4-guanidinomethyl-3-iodobenzoate radiolabeling.

    Science.gov (United States)

    Pruszynski, Marek; Koumarianou, Eftychia; Vaidyanathan, Ganesan; Revets, Hilde; Devoogdt, Nick; Lahoutte, Tony; Lyerly, H Kim; Zalutsky, Michael R

    2014-04-01

    and kidneys, for which the values were 10.4 ± 4.5 and 5.2 ± 1.5, respectively. Labeling anti-HER2 Nanobody 5F7GGC with *I-SGMIB yields a promising new conjugate for targeting HER2-expressing malignancies. Further research is needed to determine the potential utility of *I-SGMIB-5F7GGC labeled with (124)I, (123)I, and (131)I for PET and SPECT imaging and for targeted radiotherapy, respectively.

  4. Understanding specific and nonspecific toxicities: a requirement for the development of dendrimer-based pharmaceuticals

    OpenAIRE

    McNerny, Daniel Q.; Leroueil, Pascale R.; Baker, James R.

    2010-01-01

    Dendrimer conjugates for pharmaceutical development are capable of enhancing the local delivery of cytotoxic drugs. The ability to conjugate different targeting ligands to the dendrimer allows for the cytotoxic drug to be focused at the intended target cell while minimizing collateral damage in normal cells. Dendrimers offer several advantages over other polymer conjugates by creating a better defined, more monodisperse therapeutic scaffold. Toxicity from the dendrimer, targeted and nonspecif...

  5. Temperature-sensitive elastin-mimetic dendrimers: Effect of peptide length and dendrimer generation to temperature sensitivity.

    Science.gov (United States)

    Kojima, Chie; Irie, Kotaro; Tada, Tomoko; Tanaka, Naoki

    2014-06-01

    Dendrimers are synthetic macromolecules with unique structure, which are a potential scaffold for peptides. Elastin is one of the main components of extracellular matrix and a temperature-sensitive biomacromolecule. Previously, Val-Pro-Gly-Val-Gly peptides have been conjugated to a dendrimer for designing an elastin-mimetic dendrimer. In this study, various elastin-mimetic dendrimers using different length peptides and different dendrimer generations were synthesized to control the temperature dependency. The elastin-mimetic dendrimers formed β-turn structure by heating, which was similar to the elastin-like peptides. The elastin-mimetic dendrimers exhibited an inverse phase transition, largely depending on the peptide length and slightly depending on the dendrimer generation. The elastin-mimetic dendrimers formed aggregates after the phase transition. The endothermal peak was observed in elastin-mimetic dendrimers with long peptides, but not with short ones. The peptide length and the dendrimer generation are important factors to tune the temperature dependency on the elastin-mimetic dendrimer. Copyright © 2013 Wiley Periodicals, Inc.

  6. Increase in Dye:Dendrimer Ratio Decreases Cellular Uptake of Neutral Dendrimers in RAW Cells.

    Science.gov (United States)

    Vaidyanathan, Sriram; Kaushik, Milan; Dougherty, Casey; Rattan, Rahul; Goonewardena, Sascha N; Banaszak Holl, Mark M; Monano, Janet; DiMaggio, Stassi

    2016-09-12

    Neutral generation 3 poly(amidoamine) dendrimers were labeled with Oregon Green 488 (G3-OG n ) to obtain materials with controlled fluorophore:dendrimer ratios (n = 1-2), a mixture containing mostly 3 dyes per dendrimer, a mixture containing primarily 4 or more dyes per dendrimer ( n = 4+), and a stochastic mixture ( n = 4 avg ). The UV absorbance of the dye conjugates increased linearly as n increased and the fluorescence emission decreased linearly as n increased. Cellular uptake was studied in RAW cells and HEK 293A cells as a function of the fluorophore:dendrimer ratio (n). The cellular uptake of G3-OG n ( n = 3, 4+, 4 avg ) into RAW cells was significantly lower than G3-OG n ( n = 1, 2). The uptake of G3-OG n ( n = 3, 4+, 4 avg ) into HEK 293A cells was not significantly different from G3-OG 1 . Thus, the fluorophore:dendrimer ratio was observed to change the extent of uptake in the macrophage uptake mechanism but not in the HEK 293A cell. This difference in endocytosis indicates the presence of a pathway in the macrophage that is sensitive to hydrophobicity of the particle.

  7. Comparative evaluation of synthetic anti-HER2 Affibody molecules site-specifically labelled with {sup 111}In using N-terminal DOTA, NOTA and NODAGA chelators in mice bearing prostate cancer xenografts

    Energy Technology Data Exchange (ETDEWEB)

    Malmberg, Jennie; Varasteh, Zohreh; Orlova, Anna [Uppsala University, Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala (Sweden); Perols, Anna; Braun, Alexis; Eriksson Karlstroem, Amelie [AlbaNova University Centre, Division of Molecular Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, Stockholm (Sweden); Altai, Mohamed; Tolmachev, Vladimir [Uppsala University, Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala (Sweden); Sandstroem, Mattias [Uppsala University Hospital, Section of Medical Physics, Department of Oncology, Uppsala (Sweden); Garske, Ulrike [Uppsala University Hospital, Department of Medical Sciences, Section of Nuclear Medicine, Uppsala (Sweden)

    2012-03-15

    In disseminated prostate cancer, expression of human epidermal growth factor receptor type 2 (HER2) is one of the pathways to androgen independence. Radionuclide molecular imaging of HER2 expression in disseminated prostate cancer might identify patients for HER2-targeted therapy. Affibody molecules are small (7 kDa) targeting proteins with high potential as tracers for radionuclide imaging. The goal of this study was to develop an optimal Affibody-based tracer for visualization of HER2 expression in prostate cancer. A synthetic variant of the anti-HER2 Z{sub HER2:342} Affibody molecule, Z{sub HER2:S1}, was N-terminally conjugated with the chelators DOTA, NOTA and NODAGA. The conjugated proteins were biophysically characterized by electrospray ionization mass spectroscopy (ESI-MS), circular dichroism (CD) spectroscopy and surface plasmon resonance (SPR)-based biosensor analysis. After labelling with {sup 111}In, the biodistribution was assessed in normal mice and the two most promising conjugates were further evaluated for tumour targeting in mice bearing DU-145 prostate cancer xenografts. The HER2-binding equilibrium dissociation constants were 130, 140 and 90 pM for DOTA-Z{sub HER2:S1}, NOTA-Z{sub HER2:S1} and NODAGA-Z{sub HER2:S1}, respectively. A comparative study of {sup 111}In-labelled DOTA-Z{sub HER2:S1}, NOTA-Z{sub HER2:S1} and NODAGA-Z{sub HER2:S1} in normal mice demonstrated a substantial influence of the chelators on the biodistribution properties of the conjugates. {sup 111}In-NODAGA-Z{sub HER2:S1} had the most rapid clearance from blood and healthy tissues. {sup 111}In-NOTA-Z{sub HER2:S1} showed high hepatic uptake and was excluded from further evaluation. {sup 111}In-DOTA-Z{sub HER2:S1} and {sup 111}In-NODAGA-Z{sub HER2:S1} demonstrated specific uptake in DU-145 prostate cancer xenografts in nude mice. The tumour uptake of {sup 111}In-NODAGA-Z{sub HER2:S1}, 5.6 {+-} 0.4%ID/g, was significantly lower than the uptake of {sup 111}In-DOTA-Z{sub HER2:S1

  8. Doxorubicin conjugation and drug linker chemistry alter the intravenous and pulmonary pharmacokinetics of a PEGylated Generation 4 polylysine dendrimer in rats.

    Science.gov (United States)

    Leong, Nathania J; Mehta, Dharmini; McLeod, Victoria M; Kelly, Brian D; Pathak, Rashmi; Owen, David J; Porter, Christopher Jh; Kaminskas, Lisa M

    2018-05-28

    PEGylated polylysine dendrimers have demonstrated potential as inhalable drug delivery systems that can improve the treatment of lung cancers. Their treatment potential may be enhanced by developing constructs that display prolonged lung retention, together with good systemic absorption, the capacity to passively target lung tumours from the blood and highly selective, yet rapid liberation in the tumour microenvironment. This study sought to characterise how the nature of cathepsin B cleavable peptide linkers, used to conjugate doxorubicin to a PEGylated (PEG570) G4 polylysine dendrimer, affect drug liberation kinetics and intravenous and pulmonary pharmacokinetics in rats. The construct bearing a self-emolative diglycolic acid-V-Citrulline linker exhibited faster doxorubicin release kinetics compared to constructs bearing self emolative diglycolic acid-GLFG, or non-self emolative glutaric acid-GLFG linkers. The V-Citrulline construct exhibited slower plasma clearance, but faster absorption from the lungs than a GLFG construct, although mucociliary clearance and urinary elimination were unchanged. Doxorubicin-conjugation enhanced localisation in the bronchoalveolar lavage fluid compared to lung tissue, suggesting that projection of doxorubicin from the dendrimer surface reduced tissue uptake. These data show that the linker chemistry employed to conjugate drugs to PEGylated carriers can affect drug release profiles and systemic and lung disposition. Copyright © 2018. Published by Elsevier Inc.

  9. Transepithelial Transport of PEGylated Anionic Poly(amidoamine) Dendrimers: Implications for Oral Drug Delivery

    OpenAIRE

    Sweet, Deborah M.; Kolhatkar, Rohit B.; Ray, Abhijit; Swaan, Peter; Ghandehari, Hamidreza

    2009-01-01

    The purpose of this work was to assess the impact of PEGylation on transepithelial transport of anionic poly(amidoamine) dendrimers. Cytotoxicity, uptake and transport across Caco-2 cells of PEGylated G3.5 and G4.5 PAMAM dendrimers were studied. Methoxy polyethylene glycol (750 Da) was conjugated to carboxylic acid-terminated PAMAM dendrimers at feed ratios of 1, 2 and 4 PEG per dendrimer. Compared to the control, PEGylation of anionic dendrimers did not significantly alter cytotoxicity up to...

  10. Lymphatic transport and lymph node targeting of methotrexate-conjugated PEGylated dendrimers are enhanced by reducing the length of the drug linker or masking interactions with the injection site.

    Science.gov (United States)

    Ryan, Gemma M; McLeod, Victoria M; Mehta, Dharmini; Kelly, Brian D; Stanislawski, Pauline C; Owen, David J; Kaminskas, Lisa M; Porter, Christopher J H

    2017-11-01

    Drug conjugation to dendrimer-based delivery systems has been shown to enhance delivery to the lymphatic system after subcutaneous administration. Dendrimer interaction with components of the interstitium at the injection site, however, may prevent drainage from the injection site. The current study sought to vary the length of a linker employed to conjugate methotrexate (MTX) to a PEGylated dendrimer, in an attempt to reduce MTX interaction with interstitial binding sites and enhance lymphatic drainage. Dendrimers with shorter linkers resulted in higher lymphatic drainage, presumably via shielding of interaction sites by the PEG mantle, but were not retained in lymph nodes. Improved drainage of dendrimers with longer linkers was achieved through coadministration with dextran to mask interactions at the injection site while maintaining retention within the node. Enhanced drug exposure to the lymph node has the potential to enhance the treatment of lymph-node resident cancer metastases. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. HER2 monoclonal antibodies that do not interfere with receptor heterodimerization-mediated signaling induce effective internalization and represent valuable components for rational antibody-drug conjugate design.

    Science.gov (United States)

    de Goeij, Bart E C G; Peipp, Matthias; de Haij, Simone; van den Brink, Edward N; Kellner, Christian; Riedl, Thilo; de Jong, Rob; Vink, Tom; Strumane, Kristin; Bleeker, Wim K; Parren, Paul W H I

    2014-01-01

    The human epidermal growth factor receptor (HER)2 provides an excellent target for selective delivery of cytotoxic drugs to tumor cells by antibody-drug conjugates (ADC) as has been clinically validated by ado-trastuzumab emtansine (Kadcyla(TM)). While selecting a suitable antibody for an ADC approach often takes specificity and efficient antibody-target complex internalization into account, the characteristics of the optimal antibody candidate remain poorly understood. We studied a large panel of human HER2 antibodies to identify the characteristics that make them most suitable for an ADC approach. As a model toxin, amenable to in vitro high-throughput screening, we employed Pseudomonas exotoxin A (ETA') fused to an anti-kappa light chain domain antibody. Cytotoxicity induced by HER2 antibodies, which were thus non-covalently linked to ETA', was assessed for high and low HER2 expressing tumor cell lines and correlated with internalization and downmodulation of HER2 antibody-target complexes. Our results demonstrate that HER2 antibodies that do not inhibit heterodimerization of HER2 with related ErbB receptors internalize more efficiently and show greater ETA'-mediated cytotoxicity than antibodies that do inhibit such heterodimerization. Moreover, stimulation with ErbB ligand significantly enhanced ADC-mediated tumor kill by antibodies that do not inhibit HER2 heterodimerization. This suggests that the formation of HER2/ErbB-heterodimers enhances ADC internalization and subsequent killing of tumor cells. Our study indicates that selecting HER2 ADCs that allow piggybacking of HER2 onto other ErbB receptors provides an attractive strategy for increasing ADC delivery and tumor cell killing capacity to both high and low HER2 expressing tumor cells.

  12. Evaluation of an Anti-HER2 Nanobody Labeled with 225Ac for Targeted α-Particle Therapy of Cancer.

    Science.gov (United States)

    Pruszynski, Marek; D'Huyvetter, Matthias; Bruchertseifer, Frank; Morgenstern, Alfred; Lahoutte, Tony

    2018-04-02

    Human epidermal growth factor receptor type 2 (HER2) is overexpressed in numerous carcinomas. Nanobodies (Nbs) are the smallest antibody-derived fragments with beneficial characteristics for molecular imaging and radionuclide therapy. Therefore, HER2-targeting nanobodies could offer a valuable platform for radioimmunotherapy, especially when labeled with α-particle emitters, which provide highly lethal and localized radiation to targeted cells with minimal exposure to surrounding healthy tissues. In this study, the anti-HER2 2Rs15d-nanobody was conjugated with 2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid ( p-SCN-Bn-DOTA) and radiolabeled with an α-emitter 225 Ac with a high yield (>90%) and a radiochemical purity above 95%. The 225 Ac-DOTA-Nb binding affinity was 4.12 ± 0.47 nM with an immunoreactive fraction above 80%. Binding to low HER2-expressing MDA-MB-231 cells was negligible, whereas HER2-overexpressing SKOV-3 cells could be blocked with an excess of unlabeled nanobody, confirming the specificity of binding. Noncompeting binding to HER2 was observed in the presence of an excess of trastuzumab. The cell-associated fraction of 225 Ac-DOTA-Nb was 34.72 ± 16.66% over 24 h. In vitro, the radioconjugate was toxic in an HER2-mediated and dose-dependent manner, resulting in IC 50 values of 10.2 and 322.1 kBq/mL for 225 Ac-DOTA-Nb and the 225 Ac-DOTA control, respectively, on SKOV-3 cells, and 282.2 kBq/mL for 225 Ac-DOTA-Nb on MDA-MB-231 cells. Ex vivo biodistribution studies, performed in mice bearing subcutaneous HER2-overexpressing and low HER2-expressing tumors, showed a fast uptake in SKOV-3 tumors compared to MDA-MB-231 (4.01 ± 1.58% ID/g vs 0.49 ± 0.20% ID/g after 2 h), resulting also in high tumor-to-normal tissue ratios. In addition, coinjection of 225 Ac-DOTA-Nb with Gelofusine reduced kidney retention by 70%. This study shows that 225 Ac-DOTA-Nb is a promising new radioconjugate for targeted α-particle therapy

  13. Optimal specific radioactivity of anti-HER2 Affibody molecules enables discrimination between xenografts with high and low HER2 expression levels

    Energy Technology Data Exchange (ETDEWEB)

    Tolmachev, Vladimir [Uppsala University, Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala (Sweden); Uppsala University, Department of Medical Sciences, Nuclear Medicine, Uppsala (Sweden); Waallberg, Helena [Royal Institute of Technology, School of Biotechnology, Stockholm (Sweden); Sandstroem, Mattias [Uppsala University Hospital, Section of Hospital Physics, Department of Oncology, Uppsala (Sweden); Hansson, Monika; Wennborg, Anders [Affibody AB, Stockholm (Sweden); Orlova, Anna [Uppsala University, Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala (Sweden)

    2011-03-15

    Overexpression of the HER2 receptor is a biomarker for predicting those patients who may benefit from trastuzumab therapy. Radiolabelled Affibody molecules can be used to visualize HER2 expression in tumour xenografts with high sensitivity. However, previous studies demonstrated that the difference in uptake in xenografts with high and low HER2 expression levels is not proportional to the difference in expression levels. We hypothesized that discrimination between tumours with high and low HER2 expression may be improved by increasing the injected dose (reducing the specific activity) of the tracer. The influence of injected dose of anti-HER2 {sup 111}In-DOTA-Z{sub HER2} {sub 342} Affibody molecule on uptake in SKOV-3 (high HER2 expression) and LS174T (low expression) xenografts was investigated. The optimal range of injected doses enabling discrimination between xenografts with high and low expression was determined. To verify this, tumour uptake was measured in mice carrying both SKOV-3 and LS174T xenografts after injection of either 1 or 15 {mu}g {sup 111}In-DOTA-Z{sub HER2:342}. An increase in the injected dose caused a linear decrease in the radioactivity accumulation in the LS174T xenografts (low HER2 expression). For SKOV-3 xenografts, the dependence of the tumour uptake on the injected dose was less dramatic. The injection of 10-30 {mu}g {sup 111}In-DOTA-Z{sub HER2:342} per mouse led to the largest difference in uptake between the two types of tumour. Experiments in mice bearing two xenografts confirmed that the optimized injected dose enabled better discrimination of expression levels. Careful optimization of the injected dose of Affibody molecules is required for maximum discrimination between xenografts with high and low levels of HER2 expression. This information has potential relevance for clinical imaging applications. (orig.)

  14. Transport of dendrimer nanocarriers through epithelial cells via the transcellular route.

    Science.gov (United States)

    Jevprasesphant, Rachaneekorn; Penny, Jeffrey; Attwood, David; D'Emanuele, Antony

    2004-06-18

    The mechanism of transport of G3 PAMAM and surface-modified (with lauroyl chains) G3 PAMAM dendrimer nanocarriers across Caco-2 cell monolayers has been investigated. Flow-cytometry studies following quenching of extracellular fluorescence demonstrated the cellular internalisation of dendrimers. Optical sectioning of cells incubated with fluorescein isothiocyanate (FITC)-conjugated dendrimer and lauroyl-dendrimer using confocal laser scanning microscopy revealed colocalisation of a marker for cell nuclei (4',6-diamidino-2-phenylindole, DAPI) and FITC fluorescence, also suggesting cellular internalisation of dendrimers. Transmission electron microscopic analyses of cells incubated with gold-labelled G3 PAMAM dendrimers confirmed endocytosis-mediated cellular internalisation when dendrimers were applied to the apical domain of Caco-2 cells. These findings are in agreement with our previous studies using Caco-2 cell monolayers that showed a significant decrease of dendrimer uptake in the presence of colchicine (endocytosis inhibitor) and when temperature was reduced from 37 to 4 degrees C. Copyright 2004 Elsevier B.V.

  15. Controlled delivery of Gemcitabine Hydrochloride using mannosylated poly(propyleneimine) dendrimers

    International Nuclear Information System (INIS)

    Soni, Namrata; Jain, Keerti; Gupta, Umesh; Jain, N. K.

    2015-01-01

    The aim of the present investigation was to deliver Gemcitabine Hydrochloride (GmcH), an anticancer bioactive, specifically to lung tumor cells using mannosylated 4.0G poly(propyleneimine) dendrimers (M-PPI). 4.0G poly(propyleneimine) (PPI) dendrimers was synthesized using ethylenediamine as core and conjugated with mannose by ring opening reactions, followed by Schiff’s reaction in the presence of sodium acetate buffer (pH 4.0). Synthesized PPI dendrimers and mannose-conjugated dendrimers were characterized using IR, NMR spectroscopy, and scanning electron microscopy. GmcH was loaded into PPI and M-PPI dendrimers using equilibrium dialysis method to develop the formulations, GmcH-PPI and GmcH-M-PPI, respectively. The developed formulations were evaluated for drug loading, in vitro release kinetics, in vitro stability, hemolytic toxicity, cytotoxicity, pharmacokinetic, and biodistribution studies. The dendrimeric formulation of GmcH showed pH-sensitive release with faster release at acidic pH, i.e., pH 4.0 in comparison with physiological pH 7.4. M-PPI conjugate showed significant reduction in hemolytic toxicity as compared to plain 4.0G PPI dendrimers towards human erythrocytes. In the cytotoxicity studies with A-549 lung adenocarcinoma cell line, the GmcH-M-PPI formulation showed the lowest IC 50 value. Further, the pharmacokinetic and tissue distribution studies of free drug GmcH, GmcH-PPI, and GmcH-M-PPI in albino rats of Sprague–Dawley strain suggested the mean residence time of GmcH-M-PPI conjugate to be significantly higher (24.85 h) than free GmcH and GmcH-PPI. Deposition of drug (396.1 ± 4.7 after 2 h) in lung was found to be significantly higher with GmcH-M-PPI formulation in comparison with Gmch and GmcH-PPI

  16. Controlled delivery of Gemcitabine Hydrochloride using mannosylated poly(propyleneimine) dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Soni, Namrata; Jain, Keerti, E-mail: keertijain02@gmail.com; Gupta, Umesh, E-mail: umeshgupta175@gmail.com; Jain, N. K., E-mail: jnarendr@yahoo.co.in [Dr. H. S. Gour Central University, Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences (India)

    2015-11-15

    The aim of the present investigation was to deliver Gemcitabine Hydrochloride (GmcH), an anticancer bioactive, specifically to lung tumor cells using mannosylated 4.0G poly(propyleneimine) dendrimers (M-PPI). 4.0G poly(propyleneimine) (PPI) dendrimers was synthesized using ethylenediamine as core and conjugated with mannose by ring opening reactions, followed by Schiff’s reaction in the presence of sodium acetate buffer (pH 4.0). Synthesized PPI dendrimers and mannose-conjugated dendrimers were characterized using IR, NMR spectroscopy, and scanning electron microscopy. GmcH was loaded into PPI and M-PPI dendrimers using equilibrium dialysis method to develop the formulations, GmcH-PPI and GmcH-M-PPI, respectively. The developed formulations were evaluated for drug loading, in vitro release kinetics, in vitro stability, hemolytic toxicity, cytotoxicity, pharmacokinetic, and biodistribution studies. The dendrimeric formulation of GmcH showed pH-sensitive release with faster release at acidic pH, i.e., pH 4.0 in comparison with physiological pH 7.4. M-PPI conjugate showed significant reduction in hemolytic toxicity as compared to plain 4.0G PPI dendrimers towards human erythrocytes. In the cytotoxicity studies with A-549 lung adenocarcinoma cell line, the GmcH-M-PPI formulation showed the lowest IC{sub 50} value. Further, the pharmacokinetic and tissue distribution studies of free drug GmcH, GmcH-PPI, and GmcH-M-PPI in albino rats of Sprague–Dawley strain suggested the mean residence time of GmcH-M-PPI conjugate to be significantly higher (24.85 h) than free GmcH and GmcH-PPI. Deposition of drug (396.1 ± 4.7 after 2 h) in lung was found to be significantly higher with GmcH-M-PPI formulation in comparison with Gmch and GmcH-PPI.

  17. Short- and long-term cytotoxic effects of doxorubicin conjugates with dendrimers and vector protein on MCF-7/MDR1 chemoresistant breast cancer cells

    Science.gov (United States)

    Zamulaeva, I. A.; Matchuk, O. N.; Churyukina, K. A.; Kudryavtzev, V. A.; Yabbarov, N. G.; Nikolskaya, E. D.; Zhunina, O. A.; Kondrasheva, I. G.; Severin, E. S.

    2017-09-01

    The dendritic polymers (dendrimers) are perspective nanocontainers for targeted transport of anticancer drugs to tumor cells. We used polyamidoamine dendrimers of the second generation (G2) covalently conjugated with doxorubicin (Dox) and vector protein - recombinant third domain (3D) of alpha-fetoprotein. The objects of the study were MCF-7/MDR1 breast cancer cells, which demonstrated resistance to traditional anticancer agents due to high expression of P-glycoprotein. Effects of free Dox, G2 dendrimers loaded with Dox (G2-Dox), or conjugates of dendrimers with the vector protein and Dox (3D-G2-Dox) were assessed by the criteria of surviving cell number and clonogenic activity 24 hours and 11 days after treatment with the agents at Dox concentration of 2.5 μM, correspondingly. Flow cytometry was used to evaluate accumulation of Dox immediately after the treatment with the agents and removal of Dox during 24 hours of incubation in agent-free medium following by the treatment. Intracellular localization of Dox was studied using laser scanning microscopy. 3D-G2-Dox demonstrated the highest accumulation and the weakest removal from the cells in comparison with all other agents. The use of free Dox, G2-Dox, or 3D-G2-Dox resulted in a significant decrease in number of surviving cells by approximately 25-30% compared to the control (p ≤ 0.01). However, the most pronounced decrease in the clonogenic ability of cells was observed in the 3D-G2-Dox group (to 19% compared to the control, p < 0.01). Taking into account the previously obtained data on the extremely low 3D-G2-Dox accumulation in normal cells, it can be concluded that further development of 3D-G2-Dox as a possible anticancer drug is a promising way to overcome multiple drug resistance with minimal impact on normal cells.

  18. [Dendrimers in biomedical sciences and nanotechnology].

    Science.gov (United States)

    Sekowski, Szymon; Miłowska, Katarzyna; Gabryelak, Teresa

    2008-12-30

    Dendrimers are relatively new, hyper-branched polymers that have many interesting abilities. Dendrimers could be used, for example, as drug or gene carriers, contrast agents, sensors for different metal ions, and in developing innovation technology. These spherical polymers are also characterized by pharmacological activity against different bacterial and viral diseases. Dendrimers are currently being intensively investigated as anti-prion and anti-amyloid fibril agents. They can be used to build specific dendrimer films to be applied in modern technology. This review describes different uses of dendrimer particles in biomedical sciences and nanotechnology and shows advantages of their application.

  19. Current therapeutic strategies of anti-HER2 treatment in advanced breast cancer patients

    Directory of Open Access Journals (Sweden)

    Joanna Huszno

    2016-03-01

    Full Text Available The HER2/neu ( ERBB2 oncogene is amplified and/or overexpressed in approximately 20% of breast cancers, and is a strong prognostic factor for relapse and poor overall survival, particularly in node-positive patients. It is also an important predictor for response to trastuzumab, which has established efficacy against breast cancer with overexpression or amplification of the HER2 oncogene. Treatment with the anti-HER2 humanized monoclonal antibody – trastuzumab significantly improves progression-free and overall survival among patients with HER2-positive breast cancer. However, in most patients with HER2-positive metastatic breast cancer, the disease progresses occurred, what cause the need for new targeted therapies for advanced disease. In clinical trials, there are tested new drugs to improve the results of treatment for this group of patients. This paper presents new drugs introduced into clinical practice for treatment of advanced breast cancer, whose molecular target are receptors of the HER2 family. In addition, new therapeutic strategies and drugs that are currently in clinical researches are discussed.

  20. Phase I clinical trial of HER2-specific immunotherapy with concomitant HER2 kinase inhibtion

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    Hamilton Erika

    2012-02-01

    Full Text Available Abstract Background Patients with HER2-overexpressing metastatic breast cancer, despite initially benefiting from the monoclonal antibody trastuzumab and the EGFR/HER2 tyrosine kinase inhibitor lapatinib, will eventually have progressive disease. HER2-based vaccines induce polyclonal antibody responses against HER2 that demonstrate enhanced anti-tumor activity when combined with lapatinib in murine models. We wished to test the clinical safety, immunogenicity, and activity of a HER2-based cancer vaccine, when combined with lapatinib. Methods We immunized women (n = 12 with metastatic, trastuzumab-refractory, HER2-overexpressing breast cancer with dHER2, a recombinant protein consisting of extracellular domain (ECD and a portion of the intracellular domain (ICD of HER2 combined with the adjuvant AS15, containing MPL, QS21, CpG and liposome. Lapatinib (1250 mg/day was administered concurrently. Peripheral blood antibody and T cell responses were measured. Results This regimen was well tolerated, with no cardiotoxicity. Anti-HER2-specific antibody was induced in all patients whereas HER2-specific T cells were detected in one patient. Preliminary analyses of patient serum demonstrated downstream signaling inhibition in HER2 expressing tumor cells. The median time to progression was 55 days, with the majority of patients progressing prior to induction of peak anti-HER2 immune responses; however, 300-day overall survival was 92% (95% CI: 77-100%. Conclusions dHER2 combined with lapatinib was safe and immunogenic with promising long term survival in those with HER2-overexpressing breast cancers refractory to trastuzumab. Further studies to define the anticancer activity of the antibodies induced by HER2 vaccines along with lapatinib are underway. Trial registry ClinicalTrials.gov NCT00952692

  1. Restoring Lost Anti-HER-2 Th1 Immunity in Breast Cancer: A Crucial Role for Th1 Cytokines in Therapy and Prevention.

    Science.gov (United States)

    Nocera, Nadia F; Lee, M Catherine; De La Cruz, Lucy M; Rosemblit, Cinthia; Czerniecki, Brian J

    2016-01-01

    The ErbB/B2 (HER-2/neu) oncogene family plays a critical role in the development and metastatic spread of several tumor types including breast, ovarian and gastric cancer. In breast cancer, HER-2/neu is expressed in early disease development in a large percentage of DCIS lesions and its expression is associated with an increased risk of invasion and recurrence. Targeting HER-2 with antibodies such as trastuzumab or pertuzumab has improved survival, but patients with more extensive disease may develop resistance to therapy. Interestingly, response to HER-2 targeted therapies correlates with presence of immune response genes in the breast. Th1 cell production of the cytokines interferon gamma (IFNγ) and TNFα can enhance MHC class I expression, PD-L1 expression, augment apoptosis and tumor senescence, and enhances growth inhibition of many anti-breast cancer agents, including anti-estrogens and HER-2 targeted therapies. Recently, we have identified that a loss of anti-HER-2 CD4 Th1 in peripheral blood occurs during breast tumorigenesis and is dramatically diminished, even in Stage I breast cancers. The loss of anti-HER-2 Th1 response is specific and not readily reversed by standard therapies. In fact, this loss of anti-HER-2 Th1 response in peripheral blood correlates with lack of complete response to neoadjuvant therapy and diminished disease-free survival. This defect can be restored with HER-2 vaccinations in both DCIS and IBC. Correcting the anti-HER-2 Th1 response may have significant impact in improving response to HER-2 targeted therapies. Development of immune monitoring systems for anti-HER-2 Th1 to identify patients at risk for recurrence could be critical to improving outcomes, since the anti-HER-2 Th1 response can be restored by vaccination. Correction of the cellular immune response against HER-2 may prevent recurrence in high-risk patients with DCIS and IBC at risk of developing new or recurrent breast cancer.

  2. Prospective Biomarker Analysis of the Randomized CHER-LOB Study Evaluating the Dual Anti-HER2 Treatment With Trastuzumab and Lapatinib Plus Chemotherapy as Neoadjuvant Therapy for HER2-Positive Breast Cancer.

    Science.gov (United States)

    Guarneri, Valentina; Dieci, Maria Vittoria; Frassoldati, Antonio; Maiorana, Antonino; Ficarra, Guido; Bettelli, Stefania; Tagliafico, Enrico; Bicciato, Silvio; Generali, Daniele Giulio; Cagossi, Katia; Bisagni, Giancarlo; Sarti, Samanta; Musolino, Antonino; Ellis, Catherine; Crescenzo, Rocco; Conte, PierFranco

    2015-09-01

    The CHER-LOB randomized phase II study showed that the combination of lapatinib and trastuzumab plus chemotherapy increases the pathologic complete remission (pCR) rate compared with chemotherapy plus either trastuzumab or lapatinib. A biomarker program was prospectively planned to identify potential predictors of sensitivity to different treatments and to evaluate treatment effect on tumor biomarkers. Overall, 121 breast cancer patients positive for human epidermal growth factor 2 (HER2) were randomly assigned to neoadjuvant chemotherapy plus trastuzumab, lapatinib, or both trastuzumab and lapatinib. Pre- and post-treatment samples were centrally evaluated for HER2, p95-HER2, phosphorylated AKT (pAKT), phosphatase and tensin homolog, Ki67, apoptosis, and PIK3CA mutations. Fresh-frozen tissue samples were collected for genomic analyses. A mutation in PIK3CA exon 20 or 9 was documented in 20% of cases. Overall, the pCR rates were similar in PIK3CA wild-type and PIK3CA-mutated patients (33.3% vs. 22.7%; p = .323). For patients receiving trastuzumab plus lapatinib, the probability of pCR was higher in PIK3CA wild-type tumors (48.4% vs. 12.5%; p = .06). Ki67, pAKT, and apoptosis measured on the residual disease were significantly reduced from baseline. The degree of Ki67 inhibition was significantly higher in patients receiving the dual anti-HER2 blockade. The integrated analysis of gene expression and copy number data demonstrated that a 50-gene signature specifically predicted the lapatinib-induced pCR. PIK3CA mutations seem to identify patients who are less likely to benefit from dual anti-HER2 inhibition. p95-HER2 and markers of phosphoinositide 3-kinase pathway deregulation are not confirmed as markers of different sensitivity to trastuzumab or lapatinib. HER2 is currently the only validated marker to select breast cancer patients for anti-HER2 treatment; however, it is becoming evident that HER2-positive breast cancer is a heterogeneous disease. In addition, more

  3. Poly(amido amine) dendrimers in oral delivery.

    Science.gov (United States)

    Yellepeddi, Venkata K; Ghandehari, Hamidreza

    2016-01-01

    Poly(amidoamine) (PAMAM) dendrimers have been extensively investigated for oral delivery applications due to their ability to translocate across the gastrointestinal epithelium. In this Review, we highlight recent advances in the evaluation of PAMAM dendrimers as oral drug delivery carriers. Specifically, toxicity, mechanisms of transepithelial transport, models of the intestinal epithelial barrier including isolated human intestinal tissue model, detection of dendrimers, and surface modification are discussed. We also highlight evaluation of various PAMAM dendrimer-drug conjugates for their ability to transport across gastrointestinal epithelium for improved oral bioavailability. In addition, current challenges and future trends for clinical translation of PAMAM dendrimers as carriers for oral delivery are discussed.

  4. Anti-HER2 immunoliposomes for selective delivery of electron paramagnetic resonance imaging probes to HER2-overexpressing breast tumor cells

    Science.gov (United States)

    Burks, Scott R.; Macedo, Luciana F.; Barth, Eugene D.; Tkaczuk, Katherine H.; Martin, Stuart S.; Rosen, Gerald M.; Halpern, Howard J.; Brodie, Angela M.

    2014-01-01

    Electron paramagnetic resonance (EPR) imaging is an emerging modality that can detect and localize paramagnetic molecular probes (so-called spin probes) in vivo. We previously demonstrated that nitroxide spin probes can be encapsulated in liposomes at concentrations exceeding 100 mM, at which nitroxides exhibit a concentration-dependent quenching of their EPR signal that is analogous to the self-quenching of fluorescent molecules. Therefore, intact liposomes encapsulating high concentrations of nitroxides exhibit greatly attenuated EPR spectral signals, and endocytosis of such liposomes represents a cell-activated contrast-generating mechanism. After endocytosis, the encapsulated nitroxide is liberated and becomes greatly diluted in the intracellular milieu. This dequenches the nitroxides to generate a robust intracellular EPR signal. It is therefore possible to deliver a high concentration of nitroxides to cells while minimizing background signal from unendocytosed liposomes. We report here that intracellular EPR signal can be selectively generated in a specific cell type by exploiting its expression of Human Epidermal Growth Factor Receptor 2 (HER2). When targeted by anti-HER2 immunoliposomes encapsulating quenched nitroxides, Hc7 cells, which are novel HER2-overexpressing cells derived from the MCF7 breast tumor cell line, endocytose the liposomes copiously, in contrast to the parent MCF7 cells or control CV1 cells, which do not express HER2. HER2-dependent liposomal delivery enables Hc7 cells to accumulate 750 μM nitroxide intracellularly. Through the use of phantom models, we verify that this concentration of nitroxides is more than sufficient for EPR imaging, thus laying the foundation for using EPR imaging to visualize HER2-overexpressing Hc7 tumors in animals. PMID:20066490

  5. Transport and Biodistribution of Dendrimers Across Human Fetal Membranes: Implications for Intravaginal Administration of Dendrimers

    Science.gov (United States)

    Menjoge, Anupa R.; Navath, Raghavendra S.; Asad, Abbas; Kannan, Sujatha; Kim, Chong Jai; Romero, Roberto; Kannan, Rangaramanujam M.

    2010-01-01

    Dendrimers are emerging as promising topical antimicrobial agents, and as targeted nanoscale drug delivery vehicles. Topical intravaginal antimicrobial agents are prescribed to treat the ascending genital infections in pregnant women. The fetal membranes separate the extra-amniotic space and fetus. The purpose of the study is to determine if the dendrimers can be selectively used for local intravaginal application to pregnant women without crossing the membranes into the fetus. In the present study, the transport and permeability of PAMAM (poly(amidoamine)) dendrimers, across human fetal membrane (using a side-by-side diffusion chamber), and its biodistribution (using immunofluorescence) are evaluated ex-vivo. Transport across human fetal membranes (from the maternal side) was evaluated using Fluorescein (FITC), an established transplacental marker (positive control, size~ 400 Da) and fluorophore-tagged G4-PAMAM dendrimers (~ 16 kDa). The fluorophore-tagged G4-PAMAM dendrimers were synthesized and characterized using 1H NMR, MALDI TOF-MS and HPLC analysis. Transfer was measured across the intact fetal membrane (chorioamnion), and the separated chorion and amnion layers. Over a five hour period, the dendrimer transport across all the three membranes was less than transport of FITC was relatively fast with as much as 49% transport across the amnion. The permeability of FITC (7.9 × 10-7 cm2/s) through the chorioamnion was 7-fold higher than that of the dendrimer (5.8 × 10-8 cm2/s). The biodistribution showed that the dendrimers were largely present in interstitial spaces in the decidual stromal cells and the chorionic trophoblast cells (in 2.5 to 4 h) and surprisingly, to a smaller extent internalized in nuclei of trophoblast cells and nuclei and cytoplasm of stromal cells. Passive diffusion and paracellular transport appear to be the major route for dendrimer transport. The overall findings further suggest that entry of drugs conjugated to dendrimers would be

  6. Conjugated nanoliposome with the HER2/neu-derived peptide GP2 as an effective vaccine against breast cancer in mice xenograft model.

    Directory of Open Access Journals (Sweden)

    Atefeh Razazan

    Full Text Available One of the challenging issues in vaccine development is peptide and adjuvant delivery into target cells. In this study, we developed a vaccine and therapeutic delivery system to increase cytotoxic T lymphocyte (CTL response against a breast cancer model overexpressing HER2/neu. Gp2, a HER2/neu-derived peptide, was conjugated to Maleimide-mPEG2000-DSPE micelles and post inserted into liposomes composed of DMPC, DMPG phospholipids, and fusogenic lipid dioleoylphosphatidylethanolamine (DOPE containing monophosphoryl lipid A (MPL adjuvant (DMPC-DMPG-DOPE-MPL-Gp2. BALB/c mice were immunized with different formulations and the immune response was evaluated in vitro and in vivo. ELISpot and intracellular cytokine analysis by flow cytometry showed that the mice vaccinated with Lip-DOPE-MPL-GP2 incited the highest number of IFN-γ+ in CD8+ cells and CTL response. The immunization led to lower tumor sizes and longer survival time compared to the other groups of mice immunized and treated with the Lip-DOPE-MPL-GP2 formulation in both prophylactic and therapeutic experiments. These results showed that co-formulation of DOPE and MPL conjugated with GP2 peptide not only induces high antitumor immunity but also enhances therapeutic efficacy in TUBO mice model. Lip-DOPE-MPL-GP2 formulation could be a promising vaccine and a therapeutic delivery system against HER2 positive cancers and merits further investigation.

  7. Biological properties of water-soluble phosphorhydrazone dendrimers

    Directory of Open Access Journals (Sweden)

    Anne-Marie Caminade

    2013-01-01

    Full Text Available Dendrimers are hyperbranched and perfectly defined macromolecules, constituted of branches emanating from a central core in an iterative fashion. Phosphorhydrazone dendrimers constitute a special family of dendrimers, possessing one phosphorus atom at each branching point. The internal structure of these dendrimers is hydrophobic, but hydrophilic terminal groups can induce the solubility of the whole structure in water. Indeed, the properties of these compounds are mainly driven by the type of terminal groups their bear; this is especially true for the biological properties. For instance, positively charged terminal groups are efficient for transfection experiments, as drug carriers, as anti-prion agents, and as inhibitor of the aggregation of Alzheimer's peptides, whereas negatively charged dendrimers have anti-HIV properties and can influence the human immune system, leading to anti-inflammatory properties usable against rheumatoid arthritis. This review will give the most representative examples of the biological properties of water-soluble phosphorhydrazone dendrimers, organized depending on the type of terminal groups they bear.

  8. Development of a Targeted anti-HER2 scFv Chimeric Peptide for Gene Delivery into HER2-Positive Breast Cancer Cells.

    Science.gov (United States)

    Cheraghi, Roya; Nazari, Mahboobeh; Alipour, Mohsen; Majidi, Asia; Hosseinkhani, Saman

    2016-12-30

    Chimeric polymers are known as suitable carriers for gene delivery. Certain properties are critical for a polymer to be used as a gene delivery vector. A new polymer was designed for the targeted delivery of genes into breast cancer cell lines, based on MPG peptide. It is composed of different functional domains, including HIV gp41, nuclear localization sequence of SV40 T-antigen, two C-terminus repeats of histone H1, and the scFv of anti-HER2 antibody. The results demonstrated that the vector can effectively condense plasmid DNA into nanoparticles with an average size of 250nm. Moreover, fusion of the scFv portion to the carrier brought about the specific recognition of HER2. Overall, the transfection efficiency of the vector demonstrated that it could deliver the desired gene into BT-474 HER2-positive breast cancer cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Overview of the trastuzumab (Herceptin) anti-HER2 monoclonal antibody clinical program in HER2-overexpressing metastatic breast cancer. Herceptin Multinational Investigator Study Group.

    Science.gov (United States)

    Shak, S

    1999-08-01

    The recombinant humanized anti-HER2 monoclonal antibody trastuzumab (Herceptin; Genentech, San Francisco, CA) was evaluated in human clinical trials for treatment of women with metastatic breast cancer who have tumors that overexpress HER2. The trastuzumab clinical program consisted of a series of phase I, phase II, and phase III clinical trials. Clinical experience with this novel biologic has been obtained in more than 1,000 women with HER2-overexpressing metastatic breast cancer. Two pivotal trials were performed to evaluate trastuzumab efficacy and safety: (1) trastuzumab in combination with chemotherapy as first-line therapy and (2) trastuzumab as a single agent in second- and third-line chemotherapy. Preliminary results of the pivotal clinical trials that have been presented at national meetings are summarized below. The data suggest that trastuzumab will be an important new treatment option for women with HER2-overexpressing metastatic breast cancer.

  10. Poly(amido)amine (PAMAM) dendrimer-cisplatin complexes for chemotherapy of cisplatin-resistant ovarian cancer cells

    Science.gov (United States)

    Yellepeddi, Venkata Kashyap; Vangara, Kiran Kumar; Palakurthi, Srinath

    2013-09-01

    Dendrimer-cisplatin complexes were prepared using PAMAM dendrimers with terminal -NH2 and -COOH groups as well as biotin-conjugated dendrimers. Preformulation parameters of dendrimer-cisplatin complexes were studied using differential scanning calorimetry (DSC) and inductively coupled plasma-mass spectrometry (ICP-MS). Cytotoxicity and mechanism of cytotoxicity of dendrimer-cisplatin complexes was investigated in OVCAR-3, SKOV, A2780 and cisplatin-resistant CP70 human ovarian cancer cell lines. The loading of cisplatin in dendrimers was 11 % (w/w). PAMAM G4 dendrimers with amine surface groups (biotinylated and native) have shown 2.5- to 3.0-fold reduction in IC50 values in ovarian cancer cells when compared with carboxylate surface dendrimers ( p cisplatin complexes resulted in a 7.0-fold increase ( p cisplatin chemotherapy of ovarian cancer.

  11. Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells

    Directory of Open Access Journals (Sweden)

    Mitra Somenath

    2009-10-01

    Full Text Available Abstract Background Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. Methods The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm2 for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1 staining. Results Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. Conclusion We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs

  12. Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells

    International Nuclear Information System (INIS)

    Xiao, Yan; Savla, Ronak; Wagner, Paul D; Srivastava, Sudhir; He, Huixin; Gao, Xiugong; Taratula, Oleh; Treado, Stephen; Urbas, Aaron; Holbrook, R David; Cavicchi, Richard E; Avedisian, C Thomas; Mitra, Somenath

    2009-01-01

    Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm 2 for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1) staining. Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of Ig

  13. A new approach in the preparation of dendrimer-based bifunctional diethylenetriaminepentaacetic acid MR contrast agent derivatives.

    Science.gov (United States)

    Nwe, Kido; Xu, Heng; Regino, Celeste Aida S; Bernardo, Marcelino; Ileva, Lilia; Riffle, Lisa; Wong, Karen J; Brechbiel, Martin W

    2009-07-01

    In this paper, we report a new method to prepare and characterize a contrast agent based on a fourth-generation (G4) polyamidoamine (PAMAM) dendrimer conjugated to the gadolinium complex of the bifunctional diethylenetriamine pentaacetic acid derivative (1B4M-DTPA). The method involves preforming the metal-ligand chelate in alcohol prior to conjugation to the dendrimer. The dendrimer-based agent was purified by a Sephadex G-25 column and characterized by elemental analysis. The analysis and SE-HPLC data gave a chelate to dendrimer ratio of 30:1 suggesting conjugation at approximately every other amine terminal on the dendrimer. Molar relaxivity of the agent measured at pH 7.4 displayed a higher value than that of the analogous G4 dendrimer based agent prepared by the postmetal incorporation method (r(1) = 26.9 vs 13.9 mM(-1) s(-1) at 3 T and 22 degrees C). This is hypothesized to be due to the higher hydrophobicity of this conjugate and the lack of available charged carboxylate groups from noncomplexed free ligands that might coordinate to the metal and thus also reduce water exchange sites. Additionally, the distribution populations of compounds that result from the postmetal incorporation route are eliminated from the current product simplifying characterization as quality control issues pertaining to the production of such agents for clinical use as MR contrast agents. In vivo imaging in mice showed a reasonably fast clearance (t(1/2) = 24 min) suggesting a viable agent for use in clinical application.

  14. Natural dendrimers: Synthesis and in vitro characterization of glycogen-cysteamine conjugates.

    Science.gov (United States)

    Perrone, Mara; Lopedota, Angela; Liberati, Elisa; Russo, Vincenzo; Cutrignelli, Annalisa; Laquintana, Valentino; de Sousa, Irene Pereira; Franco, Massimo; Tongiani, Serena; Denora, Nunzio; Bernkop-Schnürch, Andreas

    2017-06-01

    The aim of this study was to synthesize, characterize and evaluate the mucoadhesive properties of the first thiolated hyperbranched natural polysaccharide with biodegradability and biocompatibility features. In detail, glycogen-cysteamine conjugates were synthesized through a first step of oxidative ring opening applying increasing concentrations of sodium periodate, to obtain polymers with different degrees of oxidation, and a second step of reductive amination with a constant amount of cysteamine. The obtained glycogen-cysteamine conjugates were characterized regarding their content of free and total thiol groups by Ellman's assay, biocompatibility, swelling/erosion behavior, rheological synergism and mucoadhesive properties in comparison to the unmodified glycogen. The higher the concentration of periodate was, the higher was the content of total thiol groups being in the range of 255.7±12-1194.5±82μmol/g, biocompatibility remained unaffected by these structural changes. On the contrary, the mucoadhesive properties, evaluated by tensile, rheological synergism and rotating cylinder studies, appear to be influenced by the thiol groups concentration on the glycogen. In particular the glycogen-cysteamine conjugate exhibiting the highest degree of thiolation showed a 79-fold increase in viscosity over a time period of 8h, as well as, remained attached on freshly excised porcine mucosa 32-fold longer than the unmodified polymer. The higher was the amount of conjugated thiol groups, the higher was the water absorption capacity of glycogen-cysteamine tablets in Simulated Intestinal Fluid pH 6.8 (SIF). The introduction of thiol moieties on polymer changed the characteristics of the polysaccharide by improving mucoadhesion properties. Therefore, this work represents the first study describing thiolated natural dendrimers as potential platform useful to realize appropriate mucoadhesive nanocarrier systems suitable to prolong mucosal residence time. Copyright © 2017

  15. Control of mobility in molecular organic semiconductors by dendrimer generation

    Science.gov (United States)

    Lupton, J. M.; Samuel, I. D.; Beavington, R.; Frampton, M. J.; Burn, P. L.; Bässler, H.

    2001-04-01

    Conjugated dendrimers are of interest as novel materials for light-emitting diodes. They consist of a luminescent chromophore at the core with highly branched conjugated dendron sidegroups. In these materials, light emission occurs from the core and is independent of generation. The dendron branching controls the separation between the chromophores. We present here a family of conjugated dendrimers and investigate the effect of dendron branching on light emission and charge transport. We apply a number of transport measurement techniques to thin films of a conjugated dendrimer in a light-emitting diode configuration to determine the effect of chromophore spacing on charge transport. We find that the mobility is reduced by two orders of magnitude as the size of the molecule doubles with increased branching or dendrimer generation. The degree of branching allows a unique control of mobility by molecular structure. An increase in chromophore separation also results in a reduction of intermolecular interactions, which reduces the red emission tail in film photoluminescence. We find that the steady-state charge transport is well described by a simple device model incorporating the effect of generation, and use the materials to shed light on the interpretation of transient electroluminescence data. We demonstrate the significance of the ability to tune the mobility in bilayer devices, where a more balanced charge transport can be achieved.

  16. Radiolabeling optimization and characterization of (68)Ga labeled DOTA-polyamido-amine dendrimer conjugate - Animal biodistribution and PET imaging results.

    Science.gov (United States)

    Ghai, Aanchal; Singh, Baljinder; Panwar Hazari, Puja; Schultz, Michael K; Parmar, Ambika; Kumar, Pardeep; Sharma, Sarika; Dhawan, Devinder; Kumar Mishra, Anil

    2015-11-01

    The present study describes the optimization of (68)Ga radiolabeling with PAMAM dendrimer-DOTA conjugate. A conjugate (PAMAM-DOTA) concentration of 11.69µM, provided best radiolabeling efficiency of more than 93.0% at pH 4.0, incubation time of 30.0min and reaction temperature ranging between 90 and 100°C. The decay corrected radiochemical yield was found to be 79.4±0.01%. The radiolabeled preparation ([(68)Ga]-DOTA-PAMAM-D) remained stable (radiolabeling efficiency of 96.0%) at room temperature and in serum for up to 4-h. The plasma protein binding was observed to be 21.0%. After intravenous administration, 50.0% of the tracer cleared from the blood circulation by 30-min and less than 1.0% of the injected activity remained in blood by 1.0h. The animal biodistribution studies demonstrated that the tracer excretes through the kidneys and about 0.33% of the %ID/g accumulated in the tumor at 1h post injection. The animal organ's biodistribution data was supported by animal PET imaging showing good 'non-specific' tracer uptake in tumor and excretion is primarily through kidneys. Additionally, DOTA-PAMAM-D conjugation with αVβ3 receptors targeting peptides and drug loading on the dendrimers may improve the specificity of the (68)Ga labeled product for imaging and treating angiogenesis respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Design and studies of multiple mechanism of anti-Candida activity of a new potent Trp-rich peptide dendrimers.

    Science.gov (United States)

    Zielińska, Paulina; Staniszewska, Monika; Bondaryk, Małgorzata; Koronkiewicz, Mirosława; Urbańczyk-Lipkowska, Zofia

    2015-11-13

    Eight peptide dendrimers were designed as structural mimics of natural cationic amphiphilic peptides with antifungal activity and evaluated for their anti-Candida potential against the wild type strains and mutants. Dendrimer 14 containing four Trp residues and dodecyl tail and a slightly smaller dendrimer 9 decorated with four N-methylated Trp that displayed 100 and 99.7% of growth inhibition at 16 μg/mL respectively, were selected for evaluation against the Candida albicans mutants with disabled biosynthesis of aspartic proteases responsible for host tissue colonization and morphogenesis during biofilm formation (sessile model). Flow cytometry method was employed to detect apoptotic cells with membrane alterations (phosphatidylserine translocation), and differentiation of apoptotic from necrotic cells was also performed. Simultaneous staining of cell surface phosphatidylserine with Annexin-V-Fluorescein and necrotic cells with propidium iodide was conducted. 14 at 16 μg/mL caused C. albicans cells to undergo cellular apoptosis but its increasing concentrations induced necrosis. 14 influenced C. albicans biofilm viability as well as hyphal and cell wall morphology. Confocal microscopy and cell wall staining with calcofluor white revealed that in epithelial model the cell surface structure was perturbed at MIC of peptide dendrimer. It appears that tryptophan or 1-methyltryptophan groups displayed at the surface and positive charges hidden in the dendrimer tree along with hydrocarbon tail located at C-terminus are important for the anti-Candida activity since dendrimers containing tryptamine at C-terminus showed only a moderate activity. Our results suggest that membranolytic dendrimer 14, targeting cellular apoptotic pathway and impairing the cell wall formation in mature biofilm, may be a potential multifunctional antifungal lead compound for the control of C. albicans infections. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. A single-domain antibody-linked Fab bispecific antibody Her2-S-Fab has potent cytotoxicity against Her2-expressing tumor cells.

    Science.gov (United States)

    Li, Aifen; Xing, Jieyu; Li, Li; Zhou, Changhua; Dong, Bin; He, Ping; Li, Qing; Wang, Zhong

    2016-12-01

    Her2, which is frequently overexpressed in breast cancer, is one of the most studied tumor-associated antigens for cancer therapy. Anti-HER2 monoclonal antibody, trastuzumab, has achieved significant clinical benefits in metastatic breast cancer. In this study, we describe a novel bispecific antibody Her2-S-Fab targeting Her2 by linking a single domain anti-CD16 VHH to the trastuzumab Fab. The Her2-S-Fab antibody can be efficiently expressed and purified from Escherichia coli, and drive potent cancer cell killing in HER2-overexpressing cancer cells. In xenograft model, the Her2-S-Fab suppresses tumor growth in the presence of human immune cells. Our results suggest that the bispecific Her2-S-Fab may provide a valid alternative to Her2 positive cancer therapy.

  19. An intrinsically fluorescent dendrimer as a nanoprobe of cell transport.

    Science.gov (United States)

    Al-Jamal, Khuloud T; Ruenraroengsak, Pakatip; Hartell, Nicholas; Florence, Alexander T

    2006-07-01

    Dendrimers, spherical or quasi-spherical synthetic polymers in the nano-size range, have found useful applications as prospective carriers in drug and gene delivery. The investigation of dendrimer uptake by cells has been previously achieved by the incorporation of a fluorescent dye to the dendrimer either by chemical conjugation or by physical interaction. Here we describe the synthesis of two intrinsically fluorescent lysine based cationic dendrimers which lack a fluorophore, but which has sufficient fluorescence intensity to be detected at low concentrations. The nomenclature used to describe our compounds results in, for example the 6th generation dendrimer being notated as Gly-Lys(63) (NH2)(64); Gly denotes that the compound has a glycine in the core coupled to 63 lysine branching units (Lys(63)) and that the surface has 64 free amino groups (NH2)(64). The use of these dendrimers in probing transport avoids the need for fluorescent tagging with its attendant problems. The uptake of Gly-Lys(63) (NH2)(64) into Caco-2 cells was followed using confocal microscopy. Being cationic, it first adsorbs to the cell surface, enters the cytoplasm and reaches the nucleus within 35-45 min. Estimates of the diffusion coefficient of the dendrimer within the cell cytoplasm leads to a value of 6.27 ( +/- 0.49) x 10(-11) cm(2) s(-1), which is up to 1000 times lower than the diffusion coefficient of the dendrimer in water. Intrinsically fluorescent dendrimers of different size and charge are useful probes of transport in cells.

  20. Poly(amido)amine (PAMAM) dendrimer-cisplatin complexes for chemotherapy of cisplatin-resistant ovarian cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yellepeddi, Venkata Kashyap; Vangara, Kiran Kumar; Palakurthi, Srinath, E-mail: palakurthi@tamhsc.edu [Texas A and M Health Science Center, Irma Lerma Rangel College of Pharmacy (United States)

    2013-09-15

    Dendrimer-cisplatin complexes were prepared using PAMAM dendrimers with terminal -NH{sub 2} and -COOH groups as well as biotin-conjugated dendrimers. Preformulation parameters of dendrimer-cisplatin complexes were studied using differential scanning calorimetry (DSC) and inductively coupled plasma-mass spectrometry (ICP-MS). Cytotoxicity and mechanism of cytotoxicity of dendrimer-cisplatin complexes was investigated in OVCAR-3, SKOV, A2780 and cisplatin-resistant CP70 human ovarian cancer cell lines. The loading of cisplatin in dendrimers was {approx}11 % (w/w). PAMAM G4 dendrimers with amine surface groups (biotinylated and native) have shown 2.5- to 3.0-fold reduction in IC{sub 50} values in ovarian cancer cells when compared with carboxylate surface dendrimers (p < 0.05). A correlation was observed among cytotoxicity of the complexes, cellular uptake, and platinum-DNA adduct formation. Treatment with dendrimer-cisplatin complexes resulted in a 7.0-fold increase (p < 0.05) in expression of apoptotic genes (Bcl2, Bax, p53) and 13.2- to 27.1-fold increase (p < 0.05) in the activity of caspases 3, 8, and 9 in vitro. Results suggest that PAMAM dendrimers can be used as potential carrier for cisplatin chemotherapy of ovarian cancer.

  1. Anticancer copper(II) phosphorus dendrimers are potent proapoptotic Bax activators.

    Science.gov (United States)

    Mignani, Serge; El Brahmi, Nabil; Eloy, Laure; Poupon, Joel; Nicolas, Valérie; Steinmetz, Anke; El Kazzouli, Said; Bousmina, Mosto M; Blanchard-Desce, Mireille; Caminade, Anne-Marie; Majoral, Jean-Pierre; Cresteil, Thierry

    2017-05-26

    A multivalent phosphorus dendrimer 1G 3 and its corresponding Cu-complex, 1G 3 -Cu have been recently identified as agents retaining high antiproliferative potency. This antiproliferative capacity was preserved in cell lines overexpressing the efflux pump ABC B1, whereas cross-resistance was observed in ovarian cancer cell lines resistant to cisplatin. Theoretical 3D models were constructed: the dendrimers appear as irregularly shaped disk-like nano-objects of about 22 Å thickness and 49 Å diameter, which accumulated in cells after penetration by endocytosis. To get insight in their mode of action, cell death pathways have been examined in human cancer cell lines: early apoptosis was followed by secondary necrosis after multivalent phosphorus dendrimers exposure. The multivalent plain phosphorus dendrimer 1G 3 moderately activated caspase-3 activity, in contrast with the multivalent Cu-conjugated phosphorus dendrimer 1G 3 -Cu which strikingly reduced the caspase-3 content and activity. This decrease of caspase activity is not related to the presence of copper, since inorganic copper has no or little effect on caspase-3. Conversely the potent apoptosis activation could be related to a noticeable translocation of Bax to the mitochondria, resulting in the release of AIF into the cytosol, its translocation to the nucleus and a severe DNA fragmentation, without alteration of the cell cycle. The multivalent Cu-conjugated phosphorus dendrimer is more efficient than its non-complexed analog to activate this pathway in close relationship with the higher antiproliferative potency. Therefore, this multivalent Cu-conjugated phosphorus dendrimer 1G 3 -Cu can be considered as a new and promising first-in-class antiproliferative agent with a distinctive mode of action, inducing apoptosis tumor cell death through Bax activation pathway. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. PEGylated Polyamidoamine dendrimer conjugated with tumor homing peptide as a potential targeted delivery system for glioma.

    Science.gov (United States)

    Jiang, Yan; Lv, Lingyan; Shi, Huihui; Hua, Yabing; Lv, Wei; Wang, Xiuzhen; Xin, Hongliang; Xu, Qunwei

    2016-11-01

    Glioblastoma multiforme (GBM) is the most common and aggressive primary central nervous system (CNS) tumor with a short survival time. The failure of chemotherapy is ascribed to the low transport of chemotherapeutics across the Blood Brain Tumor Barrier (BBTB) and poor penetration into tumor tissue. In order to overcome the two barriers, small nanoparticles with active targeted capability are urgently needed for GBM drug delivery. In this study, we proposed PEGylated Polyamidoamine (PAMAM) dendrimer nanoparticles conjugated with glioma homing peptides (Pep-1) as potential glioma targeting delivery system (Pep-PEG-PAMAM), where PEGylated PAMAM dendrimer nanoparticle was utilized as carrier due to its small size and perfect penetration into tumor and Pep-1 was used to overcome BBTB via interleukin 13 receptor α2 (IL-13Rα2) mediated endocytosis. The preliminary availability and safety of Pep-PEG-PAMAM as a nanocarrier for glioma was evaluated. In vitro results indicated that a significantly higher amount of Pep-PEG-PAMAM was endocytosed by U87 MG cells. In vivo fluorescence imaging of U87MG tumor-bearing mice confirmed that the fluorescence intensity at glioma site of targeted group was 2.02 folds higher than that of untargeted group (**p<0.01), and glioma distribution experiment further revealed that Pep-PEG-PAMAM exhibited a significantly enhanced accumulation and improved penetration at tumor site. In conclusion, Pep-1 modified PAMAM was a promising nanocarrier for targeted delivery of brain glioma. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Visualization of Tumor Angiogenesis Using MR Imaging Contrast Agent Gd-DTPA-anti-VEGF Receptor 2 Antibody Conjugate in a Mouse Tumor Model

    International Nuclear Information System (INIS)

    Jun, Hong Young; Yin, Hong Hua; Kim, Sun Hee; Park, Seong Hoon; Kim, Hun Soo; Yoon Kwon Ha Yoon

    2010-01-01

    To visualize tumor angiogenesis using the MRI contrast agent, Gd- DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model

  4. Visualization of Tumor Angiogenesis Using MR Imaging Contrast Agent Gd-DTPA-anti-VEGF Receptor 2 Antibody Conjugate in a Mouse Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Hong Young; Yin, Hong Hua; Kim, Sun Hee; Park, Seong Hoon; Kim, Hun Soo; Yoon Kwon Ha Yoon [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

    2010-08-15

    To visualize tumor angiogenesis using the MRI contrast agent, Gd- DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model

  5. Arg9 facilitates the translocation and downstream signal inhibition of an anti-HER2 single chain antibody

    Directory of Open Access Journals (Sweden)

    Hu Yi

    2012-07-01

    Full Text Available Abstract Background HER2 plays a critical role in the pathogenesis of many cancers and is linked to poor prognosis or cancer metastases. Monoclonal antibodies, such as Herceptin against HER2-overexpressing cancers, have showed satisfactory clinical therapeutic effect. However, they have difficulty to surmount obstacles to enter cells or blood–brain barrier. Results In this study, a cell-penetrating peptide Arg9 was linked to the C-terminus of anti-HER2 single chain antibody (MIL5scFv. Flow cytometry, confocal microscopy and electron microscopy analysis all revealed that Arg9 peptide facilitated the penetration of MIL5scFv into HER2-negative cell line NIH3T3 and orientate in mitochondria. More interestingly, Western blot assay showed the potential enhanced bioactivity of MIL5scFv-Arg9 in HER2+ cell line SKOV3, indicating that Arg9 could help large molecules (e.g. antibody to penetrate into cells and therefore enhance its anti-neoplastic function. Conclusions Our work represented an attractive by preliminary strategy to enhance the therapeutic effect of existing antibodies by entering cells easier, or more desirable, surmounting the physical barriers, especially in hard-to-reach cancers such as brain metastases cases.

  6. Effect of mannose targeting of hydroxyl PAMAM dendrimers on cellular and organ biodistribution in a neonatal brain injury model.

    Science.gov (United States)

    Sharma, Anjali; Porterfield, Joshua E; Smith, Elizabeth; Sharma, Rishi; Kannan, Sujatha; Kannan, Rangaramanujam M

    2018-06-05

    Neurotherapeutics for the treatment of central nervous system (CNS) disorders must overcome challenges relating to the blood-brain barrier (BBB), brain tissue penetration, and the targeting of specific cells. Neuroinflammation mediated by activated microglia is a major hallmark of several neurological disorders, making these cells a desirable therapeutic target. Building on the promise of hydroxyl-terminated generation four polyamidoamine (PAMAM) dendrimers (D4-OH) for penetrating the injured BBB and targeting activated glia, we explored if conjugation of targeting ligands would enhance and modify brain and organ uptake. Since mannose receptors [cluster of differentiation (CD) 206] are typically over-expressed on injured microglia, we conjugated mannose to the surface of multifunctional D4-OH using highly efficient, atom-economical, and orthogonal Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click chemistry and evaluated the effect of mannose conjugation on the specific cell uptake of targeted and non-targeted dendrimers both in vitro and in vivo. In vitro results indicate that the conjugation of mannose as a targeting ligand significantly changes the mechanism of dendrimer internalization, giving mannosylated dendrimer a preference for mannose receptor-mediated endocytosis as opposed to non-specific fluid phase endocytosis. We further investigated the brain uptake and biodistribution of targeted and non-targeted fluorescently labeled dendrimers in a maternal intrauterine inflammation-induced cerebral palsy (CP) rabbit model using quantification methods based on fluorescence spectroscopy and confocal microscopy. We found that the conjugation of mannose modified the distribution of D4-OH throughout the body in this neonatal rabbit CP model without lowering the amount of dendrimer delivered to injured glia in the brain, even though significantly higher glial uptake was not observed in this model. Mannose conjugation to the dendrimer modifies the dendrimer

  7. Design of interior-functionalized fully acetylated dendrimers for anticancer drug delivery.

    Science.gov (United States)

    Hu, Jingjing; Su, Yunzhang; Zhang, Hongfeng; Xu, Tongwen; Cheng, Yiyun

    2011-12-01

    In this study, dendrimers was synthesized by introducing functional groups into the interior pockets of fully acetylated dendrimers. NMR techniques including COSY and 2D-NOESY revealed the molecular structures of the synthesized dendrimers and the encapsulation of guest molecule such as methotrexate within their interior pockets. The synthesized polymeric nanocarriers showed much lower cytotoxicity on two cell lines than cationic dendrimers, and exhibited better performance than fully acetylated dendrimers in the sustained release of methotrexate. The results provided a new strategy in the design of non-toxic dendrimers with high performance in the delivery of anti-cancer drugs for clinical applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Antitumor activity of pan-HER inhibitors in HER2-positive gastric cancer.

    Science.gov (United States)

    Yoshioka, Takahiro; Shien, Kazuhiko; Namba, Kei; Torigoe, Hidejiro; Sato, Hiroki; Tomida, Shuta; Yamamoto, Hiromasa; Asano, Hiroaki; Soh, Junichi; Tsukuda, Kazunori; Nagasaka, Takeshi; Fujiwara, Toshiyoshi; Toyooka, Shinichi

    2018-04-01

    Molecularly targeted therapy has enabled outstanding advances in cancer treatment. Whereas various anti-human epidermal growth factor receptor 2 (HER2) drugs have been developed, trastuzumab is still the only anti-HER2 drug presently available for gastric cancer. In this study, we propose novel treatment options for patients with HER2-positive gastric cancer. First, we determined the molecular profiles of 12 gastric cancer cell lines, and examined the antitumor effect of the pan-HER inhibitors afatinib and neratinib in those cell lines. Additionally, we analyzed HER2 alteration in 123 primary gastric cancers resected from Japanese patients to clarify possible candidates with the potential to respond to these drugs. In the drug sensitivity analysis, both afatinib and neratinib produced an antitumor effect in most of the HER2-amplified cell lines. However, some cells were not sensitive to the drugs. When the molecular profiles of the cells were compared based on the drug sensitivities, we found that cancer cells with lower mRNA expression levels of IGFBP7, a tumor suppressor gene that inhibits the activation of insulin-like growth factor-1 receptor (IGF-1R), were less sensitive to pan-HER inhibitors. A combination therapy consisting of pan-HER inhibitors and an IGF-1R inhibitor, picropodophyllin, showed a notable synergistic effect. Among 123 clinical samples, we found 19 cases of HER2 amplification and three cases of oncogenic mutations. In conclusion, afatinib and neratinib are promising therapeutic options for the treatment of HER2-amplified gastric cancer. In addition to HER2 amplification, IGFBP7 might be a biomarker of sensitivity to these drugs, and IGF-1R-targeting therapy can overcome drug insensitiveness in HER2-amplified gastric cancer. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  9. Evaluation of the first 44Sc-labeled Affibody molecule for imaging of HER2-expressing tumors

    International Nuclear Information System (INIS)

    Honarvar, Hadis; Müller, Cristina; Cohrs, Susan; Haller, Stephanie; Westerlund, Kristina; Karlström, Amelie Eriksson; Meulen, Nicholas P. van der; Schibli, Roger; Tolmachev, Vladimir

    2017-01-01

    Introduction: Affibody molecules are small (58 amino acids) high-affinity proteins based on a tri-helix non-immunoglobulin scaffold. A clinical study has demonstrated that PET imaging using Affibody molecules labeled with 68 Ga (T ½ = 68 min) can visualize metastases of breast cancer expressing human epidermal growth factor receptor type 2 (HER2) and provide discrimination between tumors with high and low expression level. This may help to identify breast cancer patients benefiting from HER2-targeting therapies. The best discrimination was at 4 h post injection. Due to longer half-life, a positron-emitting radionuclide 44 Sc (T ½ = 4.04 h) might be a preferable label for Affibody molecules for imaging at several hours after injection. Methods: A synthetic second-generation anti-HER2 Affibody molecule Z HER2:2891 was labeled with 44 Sc via a DOTA-chelator conjugated to the N-terminal amino group. Binding specificity, affinity and cellular processing 44 Sc-DOTA-Z HER2:2891 and 68 Ga-DOTA-Z HER2:2891 were compared in vitro using HER2-expressing cells. Biodistribution and imaging properties of 44 Sc-DOTA-Z HER2:2891 and 68 Ga-DOTA-Z HER2:2891 were evaluated in Balb/c nude mice bearing HER2-expression xenografts. Results: The labeling yield of 98 ± 2% and specific activity of 7.8 GBq/μmol were obtained. The conjugate demonstrated specific binding to HER2-expressing SKOV3.ip cells in vitro and to SKOV3.ip xenografts in nude mice. The distribution of radioactivity at 3 h post injection was similar for 44 Sc-DOTA-Z HER2:2891 and 68 Ga-DOTA-Z HER2:2891 , but the blood clearance of the 44 Sc-labeled variant was slower and the tumor-to-blood ratio was reduced (15 ± 2 for 44 Sc-DOTA-Z HER2:2891 vs 46 ± 9 for 68 Ga-DOTA-Z HER2:2891 ). At 6 h after injection of 44 Sc-DOTA-Z HER2:2891 the tumor uptake was 8 ± 2% IA/g and the tumor-to-blood ratio was 51 ± 8. Imaging using small-animal PET/CT demonstrated that 44 Sc-DOTA-Z HER2:2891 provides specific and high

  10. Substrate-Triggered Exosite Binding: Synergistic Dendrimer/Folic Acid Action for Achieving Specific, Tight-Binding to Folate Binding Protein.

    Science.gov (United States)

    Chen, Junjie; van Dongen, Mallory A; Merzel, Rachel L; Dougherty, Casey A; Orr, Bradford G; Kanduluru, Ananda Kumar; Low, Philip S; Marsh, E Neil G; Banaszak Holl, Mark M

    2016-03-14

    Polymer-ligand conjugates are designed to bind proteins for applications as drugs, imaging agents, and transport scaffolds. In this work, we demonstrate a folic acid (FA)-triggered exosite binding of a generation five poly(amidoamine) (G5 PAMAM) dendrimer scaffold to bovine folate binding protein (bFBP). The protein exosite is a secondary binding site on the protein surface, separate from the FA binding pocket, to which the dendrimer binds. Exosite binding is required to achieve the greatly enhanced binding constants and protein structural change observed in this study. The G5Ac-COG-FA1.0 conjugate bound tightly to bFBP, was not displaced by a 28-fold excess of FA, and quenched roughly 80% of the initial fluorescence. Two-step binding kinetics were measured using the intrinsic fluorescence of the FBP tryptophan residues to give a KD in the low nanomolar range for formation of the initial G5Ac-COG-FA1.0/FBP* complex, and a slow conversion to the tight complex formed between the dendrimer and the FBP exosite. The extent of quenching was sensitive to the choice of FA-dendrimer linker chemistry. Direct amide conjugation of FA to G5-PAMAM resulted in roughly 50% fluorescence quenching of the FBP. The G5Ac-COG-FA, which has a longer linker containing a 1,2,3-triazole ring, exhibited an ∼80% fluorescence quenching. The binding of the G5Ac-COG-FA1.0 conjugate was compared to poly(ethylene glycol) (PEG) conjugates of FA (PEGn-FA). PEG2k-FA had a binding strength similar to that of FA, whereas other PEG conjugates with higher molecular weight showed weaker binding. However, no PEG conjugates gave an increased degree of total fluorescence quenching.

  11. Energy transfer dynamics in Light-Harvesting Dendrimers

    Science.gov (United States)

    Melinger, Joseph S.; McMorrow, Dale; Kleiman, Valeria D.

    2002-03-01

    We explore energy transfer dynamics in light-harvesting phenylacetylene symmetric and asymmetric dendrimers. Femtosecond pump-probe spectroscopy is used to probe the ultrafast dynamics of electronic excitations in these dendrimers. The backbone of the macromolecule consists of branches of increasing conjugation length, creating an energy gradient, which funnels energy to an accepting perylene trap. In the case of the symmetric dendrimer (nanostar), the energy transfer efficiency is known to approach nearly unity, although the nature and timescale of the energy transfer process is still unknown. For the asymmetric dendrimers, energy transfer efficiencies are very high, with the possibility of more complex transfer processes. We experimentally monitor the transport of excitons through the light-harvesting dendrimer. The transients show a number of components, with timescales ranging from <300fs to several tens of picoseconds, revealing the complex photophysics taking place in these macromolecules. We interpret our results in terms of the Förster mechanism in which energy transfer occurs through dipole-dipole interactions.

  12. (18)F-nanobody for PET imaging of HER2 overexpressing tumors.

    Science.gov (United States)

    Xavier, Catarina; Blykers, Anneleen; Vaneycken, Ilse; D'Huyvetter, Matthias; Heemskerk, Jan; Lahoutte, Tony; Devoogdt, Nick; Caveliers, Vicky

    2016-04-01

    Radiolabeled nanobodies are exciting new probes for molecular imaging due to high affinity, high specificity and fast washout from the blood. Here we present the labeling of an anti-HER2 nanobody with (18)F and its validation for in vivo assessment of HER2 overexpression. The GMP grade anti-HER2 nanobody was labeled with the prosthetic group, N-succinimidyl-4-[(18)F]fluorobenzoate ([(18)F]-SFB), and its biodistribution, tumor targeting and specificity were evaluated in mouse and rat tumor models. [(18)F]FB-anti-HER2 nanobody was prepared with a 5-15% global yield (decay corrected) and a specific activity of 24.7 ± 8.2 MBq/nmol. In vivo studies demonstrated a high specific uptake for HER2 positive xenografts (5.94 ± 1.17 and 3.74 ± 0.52%IA/g, 1 and 3h p.i.) with high tumor-to-blood and tumor-to-muscle ratios generating high contrast PET imaging. The probe presented fast clearance through the kidneys (4%IA/g at 3h p.i.). [(18)F]FB-anti-HER2 nanobody is able to image HER2 expressing tumors when co-administered with the anti-HER2 therapeutic antibody trastuzumab (Herceptin), indicating the possibility of using the tracer in patients undergoing Herceptin therapy. The GMP grade anti-HER2 nanobody was labeled with (18)F. This new PET probe for imaging HER2 overexpression in tumors has ample potential for clinical translation. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. 18F-nanobody for PET imaging of HER2 overexpressing tumors

    International Nuclear Information System (INIS)

    Xavier, Catarina; Blykers, Anneleen; Vaneycken, Ilse; D'Huyvetter, Matthias; Heemskerk, Jan; Lahoutte, Tony; Devoogdt, Nick; Caveliers, Vicky

    2016-01-01

    Introduction: Radiolabeled nanobodies are exciting new probes for molecular imaging due to high affinity, high specificity and fast washout from the blood. Here we present the labeling of an anti-HER2 nanobody with 18 F and its validation for in vivo assessment of HER2 overexpression. Methods: The GMP grade anti-HER2 nanobody was labeled with the prosthetic group, N-succinimidyl-4-[ 18 F]fluorobenzoate ([ 18 F]-SFB), and its biodistribution, tumor targeting and specificity were evaluated in mouse and rat tumor models. Results: [ 18 F]FB-anti-HER2 nanobody was prepared with a 5–15% global yield (decay corrected) and a specific activity of 24.7 ± 8.2 MBq/nmol. In vivo studies demonstrated a high specific uptake for HER2 positive xenografts (5.94 ± 1.17 and 3.74 ± 0.52%IA/g, 1 and 3 h p.i.) with high tumor-to-blood and tumor-to-muscle ratios generating high contrast PET imaging. The probe presented fast clearance through the kidneys (4%IA/g at 3 h p.i.). [ 18 F]FB-anti-HER2 nanobody is able to image HER2 expressing tumors when co-administered with the anti-HER2 therapeutic antibody trastuzumab (Herceptin), indicating the possibility of using the tracer in patients undergoing Herceptin therapy. Conclusions: The GMP grade anti-HER2 nanobody was labeled with 18 F. This new PET probe for imaging HER2 overexpression in tumors has ample potential for clinical translation.

  14. Preparation and evaluation of peptide-dendrimer-paclitaxel ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research April 2017; 16 (4): 737-742 ... conjugates for treatment of heterogeneous stage 1 non- small cell lung ... Keywords: Paclitaxel, Lung cancer, Non-small cell lung cancer, Dendrimer, Peptide, PAMAM.

  15. Optimization of an anti-HER2 nanobody expression using the Taguchi method.

    Science.gov (United States)

    Farasat, Alireza; Rahbarizadeh, Fatemeh; Ahmadvand, Davoud; Yazdian, Fatemeh

    2017-09-14

    Despite being widely used in immunotherapy of cancer, whole antibodies are limited by several disadvantages. This has led to the advent of novel biomolecules such as nanobodies. Taguchi method is a statistical experimental design to study the effect of multiple variables in biological processes. In an effort to overexpress a recombinant anti-human epidermal growth factor receptor type 2 (HER2) nanobody, we performed a detailed study to find optimal condition of temperature, induction, culture media, vector, and host strain, using Taguchi methodology. A total of 16 various experiments were designed. Total protein of the formulated cultures were assessed by Bradford test and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by size exclusion high performance liquid chromatography to quantify the relative concentration of the nanobody in different expression settings. Western blotting was performed to confirm the expression of the anti-HER2 nanobody. When, individually, optimum parameters determined by Taguchi were applied, including SHuffle strain cultured in LB medium, induced with 0.4 mM isopropyl-β-D-thio-galactoside for 18 h at 24°C, production yield further increased by about 9% (25.4 mg/L), compared to the highest expression setting. Flow cytometry and enzyme-linked immunosorbent assay result indicated improved protein binding in optimized conditions. Overall, our findings provide a basis for further investigations on economical production of recombinant nanobodies to improve production yield and activity.

  16. Development of a Topical Resveratrol Formulation for Commercial Applications Using Dendrimer Nanotechnology.

    Science.gov (United States)

    Pentek, Tyler; Newenhouse, Eric; O'Brien, Brennin; Chauhan, Abhay Singh

    2017-01-14

    Resveratrol (RSV) is well known for its anti-oxidant and anti-aging properties. However, resveratrol is insoluble in water and has stability issues. Recently, efforts were placed to prepare a resveratrol-based advanced anti-aging topical product but it contains harsh organic solvents and oils that could be harmful to the human body and the environment. Hence, we propose the use of a multifunctional dendrimer to solve the solubility and stability issues of resveratrol. A dendrimer-resveratrol complex was prepared, optimized and tested for solubility enhancement, stability in solution and cream dosage forms. We have also developed a high performance liquid chromatography method to measure the resveratrol within the final product. PAMAM dendrimers increased the solubility and stability of resveratrol in water and semisolid dosage forms. Therefore, this product would be water based 'green' formulation devoid of harsh organic solvents and oils and can be safely applied to the skin. Additionally, we have shown that the dendrimer helped to increase overall RSV loading and skin penetration of resveratrol. The dendrimer-RSV formulation was successfully scaled up towards commercialization. Dendrimer with RSV has led to an innovation in anti-aging cream and solutions that could be commercially marketed. Dendrimer-RSV complex could also be added to other product forms for additional purposes and applications.

  17. Is the skin a sanctuary for breast cancer cells during treatment with anti-HER2 antibodies?

    Science.gov (United States)

    Graziano, Vincenzo; Scognamiglio, Maria Teresa; Zilli, Marinella; Giampietro, Jamara; Vici, Patrizia; Natoli, Clara; Grassadonia, Antonino

    2015-01-01

    The occurrence of skin metastases is a common event in patients affected by advanced breast cancer, usually associated with systemic disease progression. Here we describe 2 cases of diffuse cutaneous metastases from HER2-overexpressing breast cancer occurring despite a dramatic response in liver and bone, respectively, during treatment with anti-HER2 antibodies Trastuzumab and Pertuzumab. We discuss the reasons for this discrepancy and suggest a possible implication of impaired immune response in the skin. Future research should provide strategies to overcome the induction of immune privilege in the skin in order to avoid discontinuation of effective treatments.

  18. Exciton confinement in organic dendrimer quantum wells for opto-electronic applications

    Science.gov (United States)

    Lupton, J. M.; Samuel, I. D. W.; Burn, P. L.; Mukamel, S.

    2002-01-01

    Organic dendrimers are a fascinating new class of materials for opto-electronic applications. We present coupled electronic oscillator calculations on novel nanoscale conjugated dendrimers for use in organic light-emitting diodes. Strong confinement of excitations at the center of the dendrimers is observed, which accounts for the dependence of intermolecular interactions and charge transport on the degree of branching of the dendrimer. The calculated absorption spectra are in excellent agreement with the measured data and show that benzene rings are shared between excitations on the linear segments of the hyperbranched molecules. The coupled electronic oscillator approach is ideally suited to treat large dendritic molecules.

  19. Dendrimers in drug delivery and targeting: Drug-dendrimer interactions and toxicity issues

    Directory of Open Access Journals (Sweden)

    Kanika Madaan

    2014-01-01

    Full Text Available Dendrimers are the emerging polymeric architectures that are known for their defined structures, versatility in drug delivery and high functionality whose properties resemble with biomolecules. These nanostructured macromolecules have shown their potential abilities in entrapping and/or conjugating the high molecular weight hydrophilic/hydrophobic entities by host-guest interactions and covalent bonding (prodrug approach respectively. Moreover, high ratio of surface groups to molecular volume has made them a promising synthetic vector for gene delivery. Owing to these properties dendrimers have fascinated the researchers in the development of new drug carriers and they have been implicated in many therapeutic and biomedical applications. Despite of their extensive applications, their use in biological systems is limited due to toxicity issues associated with them. Considering this, the present review has focused on the different strategies of their synthesis, drug delivery and targeting, gene delivery and other biomedical applications, interactions involved in formation of drug-dendrimer complex along with characterization techniques employed for their evaluation, toxicity problems and associated approaches to alleviate their inherent toxicity.

  20. Dendrimers in drug delivery and targeting: Drug-dendrimer interactions and toxicity issues

    Science.gov (United States)

    Madaan, Kanika; Kumar, Sandeep; Poonia, Neelam; Lather, Viney; Pandita, Deepti

    2014-01-01

    Dendrimers are the emerging polymeric architectures that are known for their defined structures, versatility in drug delivery and high functionality whose properties resemble with biomolecules. These nanostructured macromolecules have shown their potential abilities in entrapping and/or conjugating the high molecular weight hydrophilic/hydrophobic entities by host-guest interactions and covalent bonding (prodrug approach) respectively. Moreover, high ratio of surface groups to molecular volume has made them a promising synthetic vector for gene delivery. Owing to these properties dendrimers have fascinated the researchers in the development of new drug carriers and they have been implicated in many therapeutic and biomedical applications. Despite of their extensive applications, their use in biological systems is limited due to toxicity issues associated with them. Considering this, the present review has focused on the different strategies of their synthesis, drug delivery and targeting, gene delivery and other biomedical applications, interactions involved in formation of drug-dendrimer complex along with characterization techniques employed for their evaluation, toxicity problems and associated approaches to alleviate their inherent toxicity. PMID:25035633

  1. Transepithelial transport and toxicity of PAMAM dendrimers: implications for oral drug delivery.

    Science.gov (United States)

    Sadekar, S; Ghandehari, H

    2012-05-01

    This article summarizes efforts to evaluate poly(amido amine) (PAMAM) dendrimers as carriers for oral drug delivery. Specifically, the effect of PAMAM generation, surface charge and surface modification on toxicity, cellular uptake and transepithelial transport is discussed. Studies on Caco-2 monolayers, as models of intestinal epithelial barrier, show that by engineering surface chemistry of PAMAM dendrimers, it is possible to minimize toxicity while maximizing transepithelial transport. It has been demonstrated that PAMAM dendrimers are transported by a combination of paracellular and transcellular routes. Depending on surface chemistry, PAMAM dendrimers can open the tight junctions of epithelial barriers. This tight junction opening is in part mediated by internalization of the dendrimers. Transcellular transport of PAMAM dendrimers is mediated by a variety of endocytic mechanisms. Attachment or complexation of cytotoxic agents to PAMAM dendrimers enhances the transport of such drugs across epithelial barriers. A remaining challenge is the design and development of linker chemistries that are stable in the gastrointestinal tract (GIT) and the blood stream, but amenable to cleavage at the target site of action. Recent efforts have focused on the use of PAMAM dendrimers as penetration enhancers. Detailed in vivo oral bioavailability of PAMAM dendrimer-drug conjugates, as a function of physicochemical properties will further need to be assessed. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. A dual-targeting nanocarrier based on poly(amidoamine) dendrimers conjugated with transferrin and tamoxifen for treating brain gliomas.

    Science.gov (United States)

    Li, Yan; He, Hai; Jia, Xinru; Lu, Wan-Liang; Lou, Jinning; Wei, Yen

    2012-05-01

    A pH-sensitive dual-targeting drug carrier (G4-DOX-PEG-Tf-TAM) was synthesized with transferrin (Tf) conjugated on the exterior and Tamoxifen (TAM) in the interior of the fourth generation PAMAM dendrimers for enhancing the blood-brain barrier (BBB) transportation and improving the drug accumulation in the glioma cells. It was found that, on average, 7 doxorubicine (DOX) molecules, over 30 PEG(1000) and PEG(2000) chains and one Tf group were bonded on the periphery of each G4 PAMAM dendrimer, while 29 TAM molecules were encapsulated into the interior of per dendrimer. The pH-triggered DOX release was 32% at pH 4.5 and 6% at pH 7.4, indicating a comparatively fast drug release at weak acidic condition and stable state of the carrier at physiological environment. The in vitro assay of the drug transport across the BBB model showed that G4-DOX-PEG-Tf-TAM exhibited higher BBB transportation ability with the transporting ratio of 6.06% in 3 h. The carrier was internalized into C6 glioma cells upon crossing the BBB model by the coactions of TfR-mediated endocytosis and the inhibition effect of TAM to the drug efflux transports. Moreover, it also displayed the in vitro accumulation of DOX in the avascular C6 glioma spheroids made the tumor volume effectively reduced. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement

    Directory of Open Access Journals (Sweden)

    Scott D Swanson

    2008-06-01

    Full Text Available Scott D Swanson1, Jolanta F Kukowska-Latallo2, Anil K Patri5, Chunyan Chen6, Song Ge4, Zhengyi Cao3, Alina Kotlyar3, Andrea T East7, James R Baker31Department of Radiology, The University of Michigan Medical School, 2Department of Internal Medicine, The University of Michigan Medical School, 3Michigan Nanotechnology Institute for Medicine and Biological Sciences, The University of Michigan, 4Applied Physics, The University of Michigan, MD, USA; 5Present address: National Cancer Institute at Frederick (Contractor, MD, USA; 6Present address: Intel Corporation, Chandler, AZ, USA; 7Present address: Stritch School of Medicine, Chicago, ILL, USAAbstract: A target-specific MRI contrast agent for tumor cells expressing high affinity folate receptor was synthesized using generation five (G5 of polyamidoamine (PAMAM dendrimer. Surface modified dendrimer was functionalized for targeting with folic acid (FA and the remaining terminal primary amines of the dendrimer were conjugated with the bifunctional NCS-DOTA chelator that forms stable complexes with gadolinium (Gd III. Dendrimer-DOTA conjugates were then complexed with GdCl3, followed by ICP-OES as well as MRI measurement of their longitudinal relaxivity (T1 s−1 mM−1 of water. In xenograft tumors established in immunodeficient (SCID mice with KB human epithelial cancer cells expressing folate receptor (FAR, the 3D MRI results showed specific and statistically significant signal enhancement in tumors generated with targeted Gd(III-DOTA-G5-FA compared with signal generated by non-targeted Gd(III-DOTA-G5 contrast nanoparticle. The targeted dendrimer contrast nanoparticles infiltrated tumor and were retained in tumor cells up to 48 hours post-injection of targeted contrast nanoparticle. The presence of folic acid on the dendrimer resulted in specific delivery of the nanoparticle to tissues and xenograft tumor cells expressing folate receptor in vivo. We present the specificity of the dendrimer

  4. In vitro and in vivo imaging of prostate cancer angiogenesis using anti-vascular endothelial growth factor receptor 2 antibody-conjugated quantum dot

    International Nuclear Information System (INIS)

    Kwon, Haejin; Lee, Jiyeon; Song, Rita; Lee, Jung Han; Hwang, Sung Il; Lee, Hak Jong; Kim, Young Hwa

    2013-01-01

    Authors aimed to determine the targeting ability of vascular endothelial growth factor receptor 2 (VEGFR2)-conjugated quantum dots (QDs) in vitro, and apply it for a xenograft prostate cancer mouse model. Conjugation reaction of QDs was performed by using the N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and sulfo-(N-hydroxysulfosuccinimide) (Sulfo-NHS). The human umbilical vein cord endothelial cells (HUVECs) were incubated with QDs, conjugated with antiVGFR2, to see a specific binding in vitro. Fluorescent cell images were taken by a confocal microscope. The human prostate cancer cells (PC3) were injected to five nude mice on hind limbs to make the xenograft tumor model. QD-antiVEGFR2 antibody complex was injected into the tumor model and fluorescence measurements were performed at 1, 4, 9, 12, 15, and 24 hours after the injection. The specific interaction between HUVECs and QD-antiVEGFR2 antibody was clearly shown in vitro. The in vivo fluorescence image disclosed that there was an increased signal of tumor, 12 hours after the injection of QDs. By showing endothelial cells binding with QDs-antiVEGFR2 antibodyand an experimental application of the antibody for VEGFR2 imaging in the prostate cancer xenograft mouse model, we suggests that the antibody-conjugated QDs can be a potential imaging tool for angiogenesis of the cancer.

  5. Redox and pH Responsive Poly (Amidoamine Dendrimer-Heparin Conjugates via Disulfide Linkages for Letrozole Delivery

    Directory of Open Access Journals (Sweden)

    Thanh Luan Nguyen

    2017-01-01

    Full Text Available Heparin (Hep conjugated to poly (amidoamine dendrimer G3.5 (P via redox-sensitive disulfide bond (P-SS-Hep was studied. The redox and pH dual-responsive nanocarriers were prepared by a simple method that minimized many complex steps as previous studies. The functional characterization of G3.5 coated Hep was investigated by the proton nuclear magnetic resonance spectroscopy. The size and formation were characterized by the dynamic light scattering, zeta potential, and transmission electron microscopy. P-SS-Hep was spherical in shape with average diameter about 11 nm loaded with more than 20% letrozole. This drug carrier could not only eliminate toxicity to cells and improve the drugs solubility but also increase biocompatibility of the system under reductive environment of glutathione. In particular, P-SS-Hep could enhance the effectiveness of cancer therapy after removing Hep from the surface. These results demonstrated that the P-SS-Hep conjugates could be a promising candidate as redox and pH responsive nanocarriers for cancer chemotherapy.

  6. Design of dendrimer-based drug delivery nanodevices with enhanced therapeutic efficacies

    Science.gov (United States)

    Kannan, Rangaramanujam

    2007-03-01

    Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorable, `peripheral' functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug delivery. They have significant potential compared to liposomes and nanoparticles, because of the reduced macrophage update, increased cellular transport, and the ability to modulate the local environment through functional groups. We are developing nanodevices based on dendritic systems for drug delivery, that contain a high drug payload, ligands, and imaging agents, resulting in `smart' drug delivery devices that can target, deliver, and signal. In collaboration with the Children's Hospital of Michigan, Karmanos Cancer Institute, and College of Pharmacy, we are testing the in vitro and in vivo response of these nanodevices, by adapting the chemistry for specific clinical applications such as asthma and cancer. These materials are characterized by UV/Vis spectroscopy, flow cytometry, fluorescence/confocal microscopy, and appropriate animal models. Our results suggest that: (1) We can prepare drug-dendrimer conjugates with drug payloads of greater than 50%, for a variety of drugs; (2) The dendritic polymers are capable of transporting and delivering drugs into cells faster than free drugs, with superior therapeutic efficiency. This can be modulated by the surface functionality of the dendrimer; (3) For chemotherapy drugs, the conjugates are a factor of 6-20 times more effective even in drug-resistant cell lines; (4) For corticosteroidal drugs, the dendritic polymers provide higher drug residence times in the lung, allowing for passive targeting. The ability of the drug-dendrimer-ligand conjugates to target specific asthma and cancer cells is currently being explored using in vitro and in vivo animal models.

  7. A review on comparative study of PPI and PAMAM dendrimers

    International Nuclear Information System (INIS)

    Kaur, Daljeet; Jain, Keerti; Mehra, Neelesh Kumar; Kesharwani, Prashant; Jain, Narendra K.

    2016-01-01

    Dendrimers are hyperbranched, monodispersed macromolecules with multivalent functional end groups. Dendrimers have been explored as carrier for many drugs like anticancer, antiviral, antimalarial, antiprotozoal, anti tubercular drugs. Although a number of different types of dendrimers containing different core molecules, branching monomers and surface functional groups have been designed till date for drug delivery applications, yet the poly(propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers have been the most explored dendrimers in this regard. In this review, we have summarized a comparative data on PPI and PAMAM dendrimers particularly relevant to their properties, synthesis, toxicity, biomedical applications and drug delivery attributes.

  8. A review on comparative study of PPI and PAMAM dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Daljeet; Jain, Keerti, E-mail: keertijain02@gmail.com; Mehra, Neelesh Kumar [ISF College of Pharmacy, Pharmaceutical Nanotechnology Research Laboratory (India); Kesharwani, Prashant [Wayne State University, Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences (United States); Jain, Narendra K., E-mail: jnarendr@yahoo.co.in, E-mail: dr.jnarendr@gmail.com [ISF College of Pharmacy, Pharmaceutical Nanotechnology Research Laboratory (India)

    2016-06-15

    Dendrimers are hyperbranched, monodispersed macromolecules with multivalent functional end groups. Dendrimers have been explored as carrier for many drugs like anticancer, antiviral, antimalarial, antiprotozoal, anti tubercular drugs. Although a number of different types of dendrimers containing different core molecules, branching monomers and surface functional groups have been designed till date for drug delivery applications, yet the poly(propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers have been the most explored dendrimers in this regard. In this review, we have summarized a comparative data on PPI and PAMAM dendrimers particularly relevant to their properties, synthesis, toxicity, biomedical applications and drug delivery attributes.

  9. Host-guest chemistry of dendrimer-drug complexes. 2. Effects of molecular properties of guests and surface functionalities of dendrimers.

    Science.gov (United States)

    Hu, Jingjing; Cheng, Yiyun; Wu, Qinglin; Zhao, Libo; Xu, Tongwen

    2009-08-06

    The host-guest chemistry of dendrimer-drug complexes is investigated by NMR techniques, including (1)H NMR and 2D-NOESY studies. The effects of molecular properties of drug molecules (protonation ability and spatial steric hindrance of charged groups) and surface functionalities of dendrimers (positively charged amine groups and negatively charged carboxylate groups) on the host-guest interactions are discussed. Different interaction mechanisms between dendrimers and drug molecules are proposed on the basis of NMR results. Primary amine- and secondary amine-containing drugs preferentially bind to negatively charged dendrimers by strong electrostatic interactions, whereas tertiary amine and quaternary ammonium-containing drugs have weak binding ability with dendrimers due to relatively low protonation ability of the tertiary amine group and serious steric hindrance of the quaternary ammonium group. Positively charged drugs locate only on the surface of negatively charged dendrimers, whereas negatively charged drugs locate both on the surface and in the interior cavities of positively charged dendrimers. The host-guest chemistry of dendrimer-drug complexes is promising for the development of new drug delivery systems.

  10. Efficacy of Anti-HER2 Agents in Combination With Adjuvant or Neoadjuvant Chemotherapy for Early and Locally Advanced HER2-Positive Breast Cancer Patients: A Network Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Márcio Debiasi

    2018-05-01

    Full Text Available BackgroundSeveral (neoadjuvant treatments for patients with HER2-positive breast cancer have been compared in different randomized clinical trials. Since it is not feasible to conduct adequate pairwise comparative trials of all these therapeutic options, network meta-analysis offers an opportunity for more detailed inference for evidence-based therapy.MethodsPhase II/III randomized clinical trials comparing two or more different (neoadjuvant treatments for HER2-positive breast cancer patients were included. Relative treatment effects were pooled in two separate network meta-analyses for overall survival (OS and disease-free survival (DFS.Results17 clinical trials met our eligibility criteria. Two different networks of trials were created based on the availability of the outcomes: OS network (15 trials: 37,837 patients; and DFS network (17 trials: 40,992 patients. Two studies—the ExteNET and the NeoSphere trials—were included only in this DFS network because OS data have not yet been reported. The concept of the dual anti-HER2 blockade proved to be the best option in terms of OS and DFS. Chemotherapy (CT plus trastuzumab (T and lapatinib (L and CT + T + Pertuzumab (P are probably the best treatment options in terms of OS, with 62.47% and 22.06%, respectively. In the DFS network, CT + T + Neratinib (N was the best treatment option with 50.55%, followed by CT + T + P (26.59% and CT + T + L (20.62%.ConclusionThis network meta-analysis suggests that dual anti-HER2 blockade with trastuzumab plus either lapatinib or pertuzumab are probably the best treatment options in the (neoadjuvant setting for HER2-positive breast cancer patients in terms of OS gain. Mature OS results are still expected for the Aphinity trial and for the sequential use of trastuzumab followed by neratinib, the treatment that showed the best performance in terms of DFS in our analysis.

  11. Monoclonal antibody-dendrimer conjugates enable radiolabeling of antibody with markedly high specific activity with minimal loss of immunoreactivity

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, H.; Togashi, K. [Kyoto Univ. (Japan). School of Medicine; Sato, N.; Saga, T.; Nakamoto, Y.; Ishimori, T.; Konishi, J. [Dept. of Nuclear Medicine and Medical Imaging, Kyoto Univ. Graduate School of Medicine, Kyoto (Japan); Toyama, S. [Inst. for Virus Research, Kyoto Univ., Kyoto (Japan); Brechbiel, M.W. [Chemistry Section, Radiation Oncology Branch, National Cancer Inst., National Inst. of Health, Bethesda, Md. (United States)

    2000-09-01

    For the purpose of radioimmunotherapy, labelling of monoclonal antibody with high specific activity is often necessary, especially when using a radionuclide with a shorter half-life. Polyamine dendrimers (PAMAM) are novel synthetic polymeric molecules with large numbers of amine residues on their spherical surface. In order to bind large numbers of radiometals to single antibody molecules, the generation-4 PAMAM (G4), which has 64 amines, was conjugated with 43 molecules of 2-(p-isothiocyanatobenzyl)-6-methyl-diethylene triamine penta-acetic acid (1B4M), a derivative of DTPA. This product [G4-(1B4M){sub 43}] was then conjugated with OST7, a murine monoclonal IgG{sub 1}. We evaluated the achievable specific activity for {sup 111}In labeling, immunore-activity, biodistribution, and tumor targeting in mice of the {sup 111}In- or {sup 153}Gd-OST7-G4-(1B4M){sub 43} as compared with radiolabeled OST7-1B4M or 56C-1B4M. The maximum specific activity of {sup 111}In-OST7-G4-(1B4M){sub 43} and {sup 111}In-OST7-1B4M was 470 and 8.7 GBq/mg (12,700 and 263 mCi/mg), respectively. Immunoreactivity of radiolabeled OST7-G4-(1B4M){sub 43} and OST7-1B4M, as determined by the binding to KT005 cells expressing the antigen, was respectively 91% and 84% of that of {sup 125}I-labelled OST7. Biodistribution studies for preparations with maximum specific activity in normal mice 3 h after injection showed that {sup 111}In- or {sup 153}Gd-OST7-G4-(1B4M){sub 43} cleared faster from the blood and accumulated more in the liver than did {sup 111}In- or {sup 153}Gd-OST7-1B4M. The dendrimer 1B4M [G4-(1B4M){sub 64}] itself showed similar saturation effects with metals. The radioactivity in all the other organs reflected the rapid clearance of radioactivity from the blood. {sup 153}Gd-OST7-G4-(1B4M){sub 43} showed specific accumulation in the KT005 tumor. In conclusion, we could successfully bind 49 times as many metal atoms to an antibody molecule as is possible with conventional metal labeling for

  12. Expand classical drug administration ways by emerging routes using dendrimer drug delivery systems: a concise overview.

    Science.gov (United States)

    Mignani, Serge; El Kazzouli, Saïd; Bousmina, Mosto; Majoral, Jean-Pierre

    2013-10-01

    Drugs are introduced into the body by numerous routes such as enteral (oral, sublingual and rectum administration), parenteral (intravascular, intramuscular, subcutaneous and inhalation administration), or topical (skin and mucosal membranes). Each route has specific purposes, advantages and disadvantages. Today, the oral route remains the preferred one for different reasons such as ease and compliance by patients. Several nanoformulated drugs have been already approved by the FDA, such as Abelcet®, Doxil®, Abraxane® or Vivagel®(Starpharma) which is an anionic G4-poly(L-lysine)-type dendrimer showing potent topical vaginal microbicide activity. Numerous biochemical studies, as well as biological and pharmacological applications of both dendrimer based products (dendrimers as therapeutic compounds per se, like Vivagel®) and dendrimers as drug carriers (covalent conjugation or noncovalent encapsulation of drugs) were described. It is widely known that due to their outstanding physical and chemical properties, dendrimers afforded improvement of corresponding carried-drugs as dendrimer-drug complexes or conjugates (versus plain drug) such as biodistribution and pharmacokinetic behaviors. The purpose of this manuscript is to review the recent progresses of dendrimers as nanoscale drug delivery systems for the delivery of drugs using enteral, parenteral and topical routes. In particular, we focus our attention on the emerging and promising routes such as oral, transdermal, ocular and transmucosal routes using dendrimers as delivery systems. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Dendrimers for Vaccine and Immunostimulatory Uses

    DEFF Research Database (Denmark)

    Heegaard, Peter M. H.; Boas, Ulrik; Sørensen, Nanna Skall

    2010-01-01

    for efficient immunostimulating compounds (adjuvants) that can increase the efficiency of vaccines, as dendrimers can provide molecularly defined multivalent scaffolds to produce highly defined conjugates with small molecule immunostimulators and/or antigens. The review gives an overview on the use...... of dendrimers as molecularly defined carriers/presenters of small antigens, including constructs that have built-in immunostimulatory (adjuvant) properties, and as stand-alone adjuvants that can be mixed with antigens to provide efficient vaccine formulations. These approaches allow the preparation...... of molecularly defined vaccines with highly predictable and specific properties and enable knowledge-based vaccine design substituting the traditional empirically based approaches for vaccine development and production....

  14. Bispecific antibody complex pre-targeting and targeted delivery of polymer drug conjugates for imaging and therapy in dual human mammary cancer xenografts. Targeted polymer drug conjugates for cancer diagnosis and therapy

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, Ban-An; Gada, Keyur S.; Patil, Vishwesh; Panwar, Rajiv; Mandapati, Savitri [Northeastern University, Department of Pharmaceutical Sciences, Bouve College of Health Sciences, School of Pharmacy, Boston, MA (United States); Hatefi, Arash [Rutgers University, Department of Pharmaceutics, New Brunswick, NJ (United States); Majewski, Stan [West Virginia University, Department of Radiology, Morgantown, WV (United States); Weisenberger, Andrew [Thomas Jefferson National Accelerator Facility, Jefferson Lab, Newport News, VA (United States)

    2014-08-15

    Doxorubicin, a frontline chemotherapeutic agent, limited by its cardiotoxicity and other tissue toxicities, was conjugated to N-terminal DTPA-modified polyglutamic acid (D-Dox-PGA) to produce polymer pro-drug conjugates. D-Dox-PGA or Tc-99 m labeled DTPA-succinyl-polylysine polymers (DSPL) were targeted to HER2-positive human mammary carcinoma (BT-474) in a double xenografted SCID mouse model also hosting HER2-negative human mammary carcinoma (BT-20). After pretargeting with bispecific anti-HER2-affibody-anti-DTPA-Fab complexes (BAAC), anti-DTPA-Fab or only phosphate buffered saline, D-Dox-PGA or Tc-99 m DSPL were administered. Positive therapeutic control mice were injected with Dox alone at maximum tolerated dose (MTD). Only BT-474 lesions were visualized by gamma imaging with Tc-99 m-DSPL; BT-20 lesions were not. Therapeutic efficacy was equivalent in mice pretargeted with BAAC/targeted with D-Dox-PGA to mice treated only with doxorubicin. There was no total body weight (TBW) loss at three times the doxorubicin equivalent MTD with D-Dox-PGA, whereas mice treated with doxorubicin lost 10 % of TBW at 2 weeks and 16 % after the second MTD injection leading to death of all mice. Our cancer imaging and pretargeted therapeutic approaches are highly target specific, delivering very high specific activity reagents that may result in the development of a novel theranostic application. HER/2 neu specific affibody-anti-DTPA-Fab bispecific antibody pretargeting of HER2 positive human mammary xenografts enabled exquisite targeting of polymers loaded with radioisotopes for molecular imaging and doxorubicin for effective therapy without the associating non-tumor normal tissue toxicities. (orig.)

  15. Conjugation of Inulin Improves Anti-Biofilm Activity of Chitosan.

    Science.gov (United States)

    Zhang, Guiqiang; Liu, Jing; Li, Ruilian; Jiao, Siming; Feng, Cui; Wang, Zhuo A; Du, Yuguang

    2018-05-04

    Bacteria biofilm helps bacteria prevent phagocytosis during infection and increase resistance to antibiotics. Staphylococcus aureus is a Gram-positive pathogenic bacterium and is tightly associated with biofilm-related infections, which have led to great threat to human health. Chitosan, the only cationic polysaccharide in nature, has been demonstrated to have antimicrobial and anti-biofilm activities, which, however, require a relative high dosage of chitosan. Moreover, poor water solubility further restricts its applications on anti-infection therapy. Inulins are a group of polysaccharides produced by many types of plants, and are widely used in processed foods. Compared to chitosan, inulin is very soluble in water and possesses a mild antibacterial activity against certain pathogenic bacteria. In order to develop an effective strategy to treat biofilm-related infections, we introduce a method by covalent conjugation of inulin to chitosan. The physicochemical characterization of the inulin⁻chitosan conjugate was assayed, and the anti-biofilm activity was evaluated against S. aureus biofilm. The results indicated that, as compared to chitosan, this novel polysaccharide⁻polysaccharide conjugate significantly enhanced activities against S. aureus either in a biofilm or planktonic state. Of note, the conjugate also showed a broad spectrum anti-biofilm activity on different bacteria strains and low cellular toxicity to mammalian cells. These results suggested that chitosan conjugation of inulin was a viable strategy for treatment against biofilm-related infections. This finding may further spread the application of natural polysaccharides on treatments of infectious disease.

  16. Suppressors for Human Epidermal Growth Factor Receptor 2/4 (HER2/4): A New Family of Anti-Toxoplasmic Agents in ARPE-19 Cells.

    Science.gov (United States)

    Kim, Yeong Hoon; Bhatt, Lokraj; Ahn, Hye-Jin; Yang, Zhaoshou; Lee, Won-Kyu; Nam, Ho-Woo

    2017-10-01

    The effects of tyrosine kinase inhibitors (TKIs) were evaluated on growth inhibition of intracellular Toxoplasma gondii in host ARPE-19 cells. The number of tachyzoites per parasitophorous vacuolar membrane (PVM) was counted after treatment with TKIs. T. gondii protein expression was assessed by western blot. Immunofluorescence assay was performed using Programmed Cell Death 4 (PDCD4) and T. gondii GRA3 antibodies. The TKIs were divided into 3 groups; non-epidermal growth factor receptor (non-EGFR), anti-human EGFR 2 (anti-HER2), and anti-HER2/4 TKIs, respectively. Group I TKIs (nintedanib, AZD9291, and sunitinib) were unable to inhibit proliferation without destroying host cells. Group II TKIs (lapatinib, gefitinib, erlotinib, and AG1478) inhibited proliferation up to 98% equivalent to control pyrimethamine (5 μM) at 20 μM and higher, without affecting host cells. Group III TKIs (neratinib, dacomitinib, afatinib, and pelitinib) inhibited proliferation up to 98% equivalent to pyrimethamine at 1-5 μM, but host cells were destroyed at 10-20 μM. In Group I, TgHSP90 and SAG1 inhibitions were weak, and GRA3 expression was moderately inhibited. In Group II, TgHSP90 and SAG1 expressions seemed to be slightly enhanced, while GRA3 showed none to mild inhibition; however, AG1478 inhibited all proteins moderately. Protein expression was blocked in Group III, comparable to pyrimethamine. PDCD4 and GRA3 were well localized inside the nuclei in Group I, mildly disrupted in Group II, and were completely disrupted in Group III. This study suggests the possibility of a vital T. gondii TK having potential HER2/4 properties, thus anti-HER2/4 TKIs may inhibit intracellular parasite proliferation with minimal adverse effects on host cells.

  17. Rabbit antibodies for hormone receptors and HER2 evaluation in breast cancer Anticorpos de coelho para avaliação de receptores hormonais e HER2 em câncer de mama

    Directory of Open Access Journals (Sweden)

    Rafael Malagoli Rocha

    2009-01-01

    Full Text Available BACKGROUND: Novel rabbit monoclonal antibodies (RabMab for estrogen (ER, progesterone (PR receptors and HER2 evaluation by immunohistochemistry have recently been commercially released. We compared the RabMab anti-ER, anti-PR and anti-HER2 to mouse monoclonal antibodies (Mab using tissue microarrays (TMA of breast carcinomas. METHODS: Two TMA containing breast carcinomas were built. Sections were immunostained using anti-ER and anti-PR, Mab and RabMab. The sections stained for ER and PR were evaluated considering positive those tumors in which more than 1% of the tumor cell nuclei stained moderate or strong. For HER2, the immunostained sections were evaluated using the ASCO/CAP guidelines for HER2. Chromogenic in situ hybridization (CISH was used as the gold standard for HER2 evaluation. CISH was evaluated using the Zymed HER2 CISH interpretation guidelines. RESULTS: RabMab against ER have similar staining patterns compared to the 6F11 (Mab, but stronger than 1D5 (Mab from three different suppliers. The RabMab against PR provide stronger and sharper immunohistochemical signals compared to Mab. The detection of HER2 protein overexpression was more prevalent with the polyclonal antibodies and RabMab than with the Mab. These were more specific than the RabMab, which were more sensitive when compared to CISH. CONCLUSION: The novel RabMab against ER and PR showed higher intensity of staining than the Mab. The RabMab against HER2 is more sensitive than Mab, however, Mab presented more specificity than RabMab when compared to CISH for HER2 evaluation of breast carcinomas.OBJETIVOS: Novos anticorpos monoclonais de coelho (RabMab para a avaliação imuno-histoquímica de receptores de estrógeno (RE, progesterona (RP e HER2 foram lançados comercialmente. Comparamos os RabMab anti-RE, anti-RP e anti-HER2 com os anticorpos monoclonais de camundongo (Mab utilizando tissue microarrays (TMA de carcinomas de mama. MÉTODOS: Foram construídos dois TMAs de

  18. Can breast cancer patients with HER2 dual-equivocal tumours be managed as HER2-negative disease?

    Science.gov (United States)

    Tong, Yiwei; Chen, Xiaosong; Fei, Xiaochun; Lin, Lin; Wu, Jiayi; Huang, Ou; He, Jianrong; Zhu, Li; Chen, Weiguo; Li, Yafen; Shen, Kunwei

    2018-01-01

    Increasing human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC)/fluorescence in situ hybridisation (FISH) dual-equivocal breast tumours are reported after the 2013 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guideline update. The aim of this study is to investigate the clinico-pathologic characteristics, treatment patterns and disease outcome of these patients with HER2 dual-equivocal tumours. Patients with HER2 IHC 2+ and available FISH results were retrospectively analysed from the Comprehensive Breast Health Center, Shanghai Ruijin Hospital. The 2013 ASCO/CAP guideline was applied to define HER2-positive, dual-equivocal and -negative groups. Patient characteristics, systemic treatment patterns and survival were compared among these groups. Reverse transcriptase-polymerase chain reaction-based assays were applied to test HER2 mRNA expression level. Among 691 patients included, 133 (19.25%) were HER2 positive, 25 (3.62%) were HER2 dual-equivocal and 533 (77.13%) were HER2 negative. Univariate and multivariate analyses stated that HER2 dual-equivocal tumours shared more similarity with HER2-negative tumours, whereas HER2-positive tumours had rather different clinico-pathologic features. HER2 dual-equivocal tumours had similar HER2 mRNA levels compared with HER2-negative tumours (P = 0.26), which were much less compared with HER2-positive breast cancer. Besides, adjuvant systemic treatment patterns were comparable between HER2-negative and dual-equivocal tumours, and none of HER2 dual-equivocal patients received anti-HER2 treatment. There was no survival difference among these three groups (P = 0.43). HER2 dual-equivocal tumours share more similarity with HER2-negative disease in terms of clinico-pathologic features, HER2 mRNA levels, adjuvant systemic treatment patterns and disease outcome, which deserves further clinical evaluation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Dendrimer sensors probed with neutron reflectometry

    International Nuclear Information System (INIS)

    Cavaye, Hamish; Smith, Arthur R.G.; Burn, Paul L.; Lo, Shih-Chun; Meredith, Paul; Gentle, Ian R.; James, Michael; Nelson, Andrew

    2009-01-01

    Full text: Oxidative photoluminescence (PL) quenching utilizing conjugated polymers as the sensing has proved to be one of the best of many methods for sensing explosive analytes.[1] However are a number of issues that can make polymers difficult to work with, including complex morphologies reproducibility of syntheses, and the need to include elaborate structures to reduce the packing of the polymer chains. Dendrimers, consisting of a core, dendrons, and surface groups, address these issues by being monodisperse and modular in their design. Determining how analytes are sequestered into thin films is important for solid-state sensors. We show that thin (230 ± 30 A ) and thick (750 ± 50 A) films of a first-generation dendrimer comrised of 2-ethylhexyloxy surface groups, biphenyl-based dendrons, and a 9,9,9',9'-tetra-n-propyl-2,2'-bifluorene core, can rapidly and reversibly detect p-nitrotoll oxidative luminescence quenching. For both the thin and thick films the PL is quenched by just 4 s . Combined PL and neutron reflectometry measurements on pristine and analyte-satura showed that during the adsorption process the films swelled, being on average 4% thicker for thin and thick dendrimer films. At the same time the PL was completely quenched. On removal of the analyte the films returned to their original thickness and scattering length density, and the restored, showing that the sensing process was fully reversible.

  20. Enzyme-responsive doxorubicin release from dendrimer nanoparticles for anticancer drug delivery

    Directory of Open Access Journals (Sweden)

    Lee SJ

    2015-08-01

    Full Text Available Sang Joon Lee,1,* Young-Il Jeong,2,* Hyung-Kyu Park,3 Dae Hwan Kang,2,4 Jong-Suk Oh,3 Sam-Gyu Lee,5 Hyun Chul Lee31Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju, 2Biomedical Research Institute, Pusan National University Hospital, Busan, 3Department of Microbiology, Chonnam National University Medical School, Gwangju, 4Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Gyeongnam, 5Department of Physical and Rehabilitation Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea*These authors contributed equally to this workBackground: Since cancer cells are normally over-expressed cathepsin B, we synthesized dendrimer-methoxy poly(ethylene glycol (MPEG-doxorubicin (DOX conjugates using a cathepsin B-cleavable peptide for anticancer drug targeting.Methods: Gly-Phe-Leu-Gly peptide was conjugated with the carboxylic acid end groups of a dendrimer, which was then conjugated with MPEG amine and doxorubicin by aid of carbodiimide chemistry (abbreviated as DendGDP. Dendrimer-MPEG-DOX conjugates without Gly-Phe-Leu-Gly peptide linkage was also synthesized for comparison (DendDP. Nanoparticles were then prepared using a dialysis procedure.Results: The synthesized DendGDP was confirmed with 1H nuclear magnetic resonance spectroscopy. The DendDP and DendGDP nanoparticles had a small particle size of less than 200 nm and had a spherical morphology. DendGDP had cathepsin B-sensitive drug release properties while DendDP did not show cathepsin B sensitivity. Further, DendGDP had improved anticancer activity when compared with doxorubicin or DendDP in an in vivo CT26 tumor xenograft model, ie, the volume of the CT26 tumor xenograft was significantly inhibited when compared with xenografts treated with doxorubicin or DendDP nanoparticles. The DendGDP nanoparticles were found to be relatively concentrated in the tumor tissue and

  1. SU-E-I-81: Targeting of HER2-Expressing Tumors with Dual PET-MR Imaging Probes

    Energy Technology Data Exchange (ETDEWEB)

    Xu, P; Peng, Y; Sun, M; Yang, X [Suzhou Institute of Biomedical Engineering and Technology Chinese Academy o, Suzhou, Jiangsu (China)

    2015-06-15

    Purpose: The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Trastuzumab, effective in about 15 % of women with breast cancer, downregulates signalling through the Akt/PI3K and MAPK pathways.These pathways modulate metabolism which can be monitored by positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: The relationship between response of HER2 overexpressing tumours and changes in imaging PET or SPECT and MRI will be examined by a integrated bimodal imaging probe.Small (7 kDa) high-affinity anti-HER2 Affibody molecules and KCCYSL targeting peptide may be suitable tracers for visualization of HER2-expressing tumors. Peptide-conjugated iron oxide nanoparticles (Fe3O4 NPs) as MRI imaging and CB-TE2A as PET imaging are integrated into a single synthetic molecule in the HER2 positive cancer. Results: One of targeted contrast bimodal imaging probe agents was synthesized and evaluated to target HER2-expressing tumors in a HER2 positive rat model. We will report the newest results regarding the development of bimodal imaging probes. Conclusion: The preliminary results of the bimodal imaging probe presents high correlation of MRI signal and PET imaging intensity in vivo. This unique feature can hardly be obtained by single model contrast agents. It is envisioned that this bimodal agents can hold great potential for accurate detection of HER2-expressing tumors which are critical for clinical management of the disease.

  2. 64Cu-Labeled LyP-1-Dendrimer for PET-CT Imaging of Atherosclerotic Plaque

    Science.gov (United States)

    2015-01-01

    The ability to detect and quantify macrophage accumulation can provide important diagnostic and prognostic information for atherosclerotic plaque. We have previously shown that LyP-1, a cyclic 9-amino acid peptide, binds to p32 proteins on activated macrophages, facilitating the visualization of atherosclerotic plaque with PET. Yet, the in vivo plaque accumulation of monomeric [18F]FBA-LyP-1 was low (0.31 ± 0.05%ID/g). To increase the avidity of LyP-1 constructs to p32, we synthesized a dendritic form of LyP-1 on solid phase using lysine as the core structural element. Imaging probes (FAM or 6-BAT) were conjugated to a lysine or cysteine on the dendrimer for optical and PET studies. The N-terminus of the dendrimer was further modified with an aminooxy group in order to conjugate LyP-1 and ARAL peptides bearing a ketone. Oxime ligation of peptides to both dendrimers resulted in (LyP-1)4- and (ARAL)4-dendrimers with optical (FAM) and PET probes (6-BAT). For PET-CT studies, (LyP-1)4- and (ARAL)4-dendrimer-6-BAT were labeled with 64Cu (t1/2 = 12.7 h) and intravenously injected into the atherosclerotic (ApoE–/–) mice. After two hours of circulation, PET-CT coregistered images demonstrated greater uptake of the (LyP-1)4-dendrimer-64Cu than the (ARAL)4-dendrimer-64Cu in the aortic root and descending aorta. Ex vivo images and the biodistribution acquired at three hours after injection also demonstrated a significantly higher uptake of the (LyP-1)4-dendrimer-64Cu (1.1 ± 0.26%ID/g) than the (ARAL)4-dendrimer-64Cu (0.22 ± 0.05%ID/g) in the aorta. Similarly, subcutaneous injection of the LyP-1-dendrimeric carriers resulted in preferential accumulation in plaque-containing regions over 24 h. In the same model system, ex vivo fluorescence images within aortic plaque depict an increased accumulation and penetration of the (LyP-1)4-dendrimer-FAM as compared to the (ARAL)4-dendrimer-FAM. Taken together, the results suggest that the (LyP-1)4-dendrimer can be applied for in

  3. Targeting human liver cancer cells with lactobionic acid-G(4)-PAMAM-FITC sorafenib loaded dendrimers.

    Science.gov (United States)

    Iacobazzi, Rosa Maria; Porcelli, Letizia; Lopedota, Angela Assunta; Laquintana, Valentino; Lopalco, Antonio; Cutrignelli, Annalisa; Altamura, Emiliano; Di Fonte, Roberta; Azzariti, Amalia; Franco, Massimo; Denora, Nunzio

    2017-08-07

    Reported here is the synthesis and biological evaluation of the asialoglycoprotein receptor (ASGP-R) targeted fourth generation poliamidoamine dendrimer (G(4)-PAMAM) loaded with sorafenib. The ASGP-R targeted dendrimer was obtained by conjugation of Lactobionic acid (La) to the G(4)-PAMAM dendrimer, followed by acetylation (Ac) of the free amino groups in order to reduce the non-specific interactions with the cell membrane. Moreover, by additionally grafting fluorescein (FITC), it was easy to characterize the internalization pathway and the intracellular fate of the targeted dendrimer Ac-La-G(4)-PAMAM-FITC. In vitro experiments performed on HepG-2 and HLE cell lines, allowed to study the ability of the dendrimers to affect the cell vitality. Confocal microscopy and cytofluorimetric analysis confirmed higher binding and uptake ability of the Ac-La-G(4)-PAMAM-FITC dendrimer in well differentiated and ASGP-R expressing human liver cancer cell line HepG-2 compared non-expressing HLE cells. Ac-La-G(4)-PAMAM-FITC dendrimer loaded with sorafenib was stable and showed sustained sorafenib release. As evidenced by the cytotoxicity studies, sorafenib included in the dendrimer maintained its effectiveness, and was able to produce a longer lasting effect over the time compared to molar equivalent doses of free sorafenib. This new targeted dendrimer appears to be a suitable carrier for the delivery of sorafenib to liver cancer cells expressing ASGP-R. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. tabAnti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO)

    International Nuclear Information System (INIS)

    Menendez, Javier A; Vazquez-Martin, Alejandro; Garcia-Villalba, Rocio; Carrasco-Pancorbo, Alegria; Oliveras-Ferraros, Cristina; Fernandez-Gutierrez, Alberto; Segura-Carretero, Antonio

    2008-01-01

    The effects of the olive oil-rich Mediterranean diet on breast cancer risk might be underestimated when HER2 (ERBB2) oncogene-positive and HER2-negative breast carcinomas are considered together. We here investigated the anti-HER2 effects of phenolic fractions directly extracted from Extra Virgin Olive Oil (EVOO) in cultured human breast cancer cell lines. Solid phase extraction followed by semi-preparative high-performance liquid chromatography (HPLC) was used to isolate phenolic fractions from commercial EVOO. Analytical capillary electrophoresis coupled to mass spectrometry was performed to check for the composition and to confirm the identity of the isolated fractions. EVOO polyphenolic fractions were tested on their tumoricidal ability against HER2-negative and HER2-positive breast cancer in vitro models using MTT, crystal violet staining, and Cell Death ELISA assays. The effects of EVOO polyphenolic fractions on the expression and activation status of HER2 oncoprotein were evaluated using HER2-specific ELISAs and immunoblotting procedures, respectively. Among the fractions mainly containing the single phenols hydroxytyrosol and tyrosol, the polyphenol acid elenolic acid, the lignans (+)-pinoresinol and 1-(+)-acetoxypinoresinol, and the secoiridoids deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (i.e. secoiridoids and lignans) were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation occurred regardless the molecular mechanism

  5. tabAnti-HER2 (erbB-2 oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO

    Directory of Open Access Journals (Sweden)

    Carrasco-Pancorbo Alegria

    2008-12-01

    Full Text Available Abstract Background The effects of the olive oil-rich Mediterranean diet on breast cancer risk might be underestimated when HER2 (ERBB2 oncogene-positive and HER2-negative breast carcinomas are considered together. We here investigated the anti-HER2 effects of phenolic fractions directly extracted from Extra Virgin Olive Oil (EVOO in cultured human breast cancer cell lines. Methods Solid phase extraction followed by semi-preparative high-performance liquid chromatography (HPLC was used to isolate phenolic fractions from commercial EVOO. Analytical capillary electrophoresis coupled to mass spectrometry was performed to check for the composition and to confirm the identity of the isolated fractions. EVOO polyphenolic fractions were tested on their tumoricidal ability against HER2-negative and HER2-positive breast cancer in vitro models using MTT, crystal violet staining, and Cell Death ELISA assays. The effects of EVOO polyphenolic fractions on the expression and activation status of HER2 oncoprotein were evaluated using HER2-specific ELISAs and immunoblotting procedures, respectively. Results Among the fractions mainly containing the single phenols hydroxytyrosol and tyrosol, the polyphenol acid elenolic acid, the lignans (+-pinoresinol and 1-(+-acetoxypinoresinol, and the secoiridoids deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (i.e. secoiridoids and lignans were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation

  6. Structural analysis of binding functionality of folic acid-PEG dendrimers against folate receptor.

    Science.gov (United States)

    Sampogna-Mireles, Diana; Araya-Durán, Ingrid D; Márquez-Miranda, Valeria; Valencia-Gallegos, Jesús A; González-Nilo, Fernando D

    2017-03-01

    Dendrimers functionalized with folic acid (FA) are drug delivery systems that can selectively target cancer cells with folate receptors (FR-α) overexpression. Incorporation of polyethylene glycol (PEG) can enhance dendrimers solubility and pharmacokinetics, but ligand-receptor binding must not be affected. In this work we characterized, at atomic level, the binding functionality of conventional site-specific dendrimers conjugated with FA with PEG 750 or PEG 3350 as a linker. After Molecular Dynamics simulation, we observed that both PEG's did not interfere over ligand-receptor binding functionality. Although binding kinetics could be notably affected, the folate fragment from both dendrimers remained exposed to the solvent before approaching selectively to FR-α. PEG 3350 provided better solubility and protection from enzymatic degradation to the dendrimer than PEG 750. Also, FA-PEG3350 dendrimer showed a slightly better interaction with FR-α than FA-PEG750 dendrimer. Therefore, theoretical evidence supports that both dendrimers are suitable as drug delivery systems for cancer therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Development of TREN dendrimers over mesoporous SBA-15 for CO2 adsorption

    International Nuclear Information System (INIS)

    Bhagiyalakshmi, Margandan; Park, Sang Do; Cha, Wang Seog; Jang, Hyun Tae

    2010-01-01

    Mesoporous SBA-15 was synthesized using rice husk ash (RHA) as the silica source and their defective Si-OH groups were grafted with tris(2-aminoethyl) amine (TREN) dendrimers generation through step-wise growth technique. The X-ray diffraction (XRD) and nitrogen adsorption/desorption results of parent SBA-15 obtained from RHA, suggests its resemblance with SBA-15 synthesized using conventional silica sources. Furthermore, the nitrogen adsorption/desorption results of SBA-15/TREN dendrimer generations (G1-G3) illustrates the growth of dendrimer inside the mesopores of SBA-15 and their CO 2 adsorption capacity was determined at 25 deg. C. The maximum CO 2 adsorption capacity of 5-6 and 7-8 wt% over second and third dendrimer generation was observed which is discernibly higher than the reported melamine and PAMAM dendrimers. The experimental CO 2 adsorption capacity was found to be less than theoretically calculated CO 2 adsorption capacity due to inter and intra molecular amidation as result of steric hindrance during the dendrimer growth. These SBA-15/TREN dendrimer generations also exhibit thermal stability up to 350 deg. C and CO 2 adsorption capacity remains unaltered upon seven consecutive runs.

  8. Immunohistochemical detection of Her-2/neu overexpression in ...

    African Journals Online (AJOL)

    Materials and Methods: Immunohistochemical staining for Her-2/neu was performed on 10% formalin-fixed, paraffinembedded primary carcinoma of the breast from 83 patients, between 2003 and 2007 using anti-Her-2/neu rabbit polyclonal antibody (DakoCytomation, CA, USA) and reactivity detected by an avidin-biotin ...

  9. Self/anti-self charge conjugate states in the helicity basis

    International Nuclear Information System (INIS)

    Dvoeglazov, Valeriy V.

    2013-01-01

    We construct self/anti-self charge conjugate (Majorana-like) states for the (1/2,0)⊕(0,1/2) representation of the Lorentz group, and their analogs for higher spins within the quantum field theory. The problem of the basis rotations and that of the selection of phases in the Dirac-like and Majorana-like field operators are considered. The discrete symmetries properties (P, C, T) are studied. Particular attention has been paid to the question of (anti)commutation of the Charge conjugation operator and the Parity in the helicity basis. Dynamical equations have also been presented. In the (1/2,0)⊕(0,1/2) representation they obey the Dirac-like equation with eight components, which has been first introduced by Markov. Thus, the Fock space for corresponding quantum fields is doubled (as shown by Ziino). The chirality and the helicity (two concepts which are frequently confused in the literature) for Dirac and Majorana states have been discussed

  10. A virosomal formulated Her-2/neu multi-peptide vaccine induces Her-2/neu-specific immune responses in patients with metastatic breast cancer: a phase I study.

    Science.gov (United States)

    Wiedermann, Ursula; Wiltschke, C; Jasinska, J; Kundi, M; Zurbriggen, R; Garner-Spitzer, E; Bartsch, R; Steger, G; Pehamberger, H; Scheiner, O; Zielinski, C C

    2010-02-01

    We have previously shown in mice that vaccination with three Her-2-peptides representing B-cell epitopes of the extracellular domain of Her-2/neu induces Her-2/neu-specific IgG antibodies with strong anti-tumor activity in vitro and in vivo. We have now finalized a phase I clinical trial with an anti-Her-2/neu vaccine-construct of immunopotentiating reconstituted influenza virosomes with the three peptides in patients with metastatic breast cancer (MBC). Ten MBC patients with low protein overexpression of Her-2/neu of MBC (+ or ++ upon immunohistochemistry, FISH negative) and positive hormone receptor status were enrolled in a single center phase I study. The virosomal formulated vaccine, consisting of 10 microg/peptide, was intramuscularly applied three times on days 1, 28, and 56. The primary endpoint of the study, which lasted 12 weeks, was safety, the secondary endpoint immunogenicity. Local erythema at the injection site was the only vaccine-related side effect occurring in four patients. In 8 of 10 patients an increase in peptide-specific antibody titer measured by ELISA was found. Importantly, the induced antibodies were also directed against the native Her-2/neu protein. Cellular immune responses, as measured by in vitro production of IL-2, IFN-c, and TNF-a of PBMCs showed a marked increase after vaccination in the majority of vaccinees. Notably, the number of CD4+CD25+Foxp3+T regulatory cells, which were significantly increased compared to healthy controls prior to vaccination, was markedly reduced following vaccination. In all, the immunological responses after vaccination indicated that the patients in stage IV of disease were immunocompetent and susceptible to vaccination. The Her-2/neu multipeptide vaccine was safe, well tolerated and effective in overcoming immunological tolerance to Her-2/neu. The induction of anti-Her-2-specific antibodies could result in clinical benefit comparable to passive anti-Her-2 antibody therapy.

  11. Targeting Mast Cells and Basophils with Anti-FcεRIα Fab-Conjugated Celastrol-Loaded Micelles Suppresses Allergic Inflammation.

    Science.gov (United States)

    Peng, Xia; Wang, Juan; Li, Xianyang; Lin, Lihui; Xie, Guogang; Cui, Zelin; Li, Jia; Wang, Yuping; Li, Li

    2015-12-01

    Mast cells and basophils are effector cells in the pathophysiology of allergic diseases. Targeted elimination of these cells may be a promising strategy for the treatment of allergic disorders. Our present study aims at targeted delivery of anti-FcεRIα Fab-conjugated celastrol-loaded micelles toward FcεRIα receptors expressed on mast cells and basophils to have enhanced anti-allergic effect. To achieve this aim, we prepared celastrol-loaded (PEO-block-PPO-block-PEO, Pluronic) polymeric nanomicelles using thin-film hydration method. The anti-FcεRIα Fab Fragment was then conjugated to carboxyl groups on drug-loaded micelles via EDC amidation reaction. The anti-FcεRIα Fab-conjugated celastrol-loaded micelles revealed uniform particle size (93.43 ± 12.93 nm) with high loading percentage (21.2 ± 1.5% w/w). The image of micelles showed oval and rod like. The anti-FcεRIα Fab-conjugated micelles demonstrated enhanced cellular uptake and cytotoxity toward target KU812 cells than non-conjugated micelles in vitro. Furthermore, diffusion of the drug into the cells allowed an efficient induction of cell apoptosis. In mouse model of allergic asthma, treatment with anti-FcεRIα Fab-conjugated micelles increased lung accumulation of micelles, and significantly reduced OVA-sIgE, histamine and Th2 cytokines (IL-4, IL-5, TNF-α) levels, eosinophils infiltration and mucus production. In addition, in mouse model of passive cutaneous anaphylaxis, anti-FcεRIα Fab-conjugated celastrol-loaded micelles treatment significantly decreased extravasated evan's in the ear. These results indicate that anti-FcεRIα Fab-conjugated celastrol-loaded micelles can target and selectively kill mast cells and basophils which express FcεRIα, and may be efficient reagents for the treatment of allergic disorders and mast cell related diseases.

  12. Inhibition of the norepinephrine transporter by χ-conotoxin dendrimers.

    Science.gov (United States)

    Wan, Jingjing; Brust, Andreas; Bhola, Rebecca F; Jha, Prerna; Mobli, Mehdi; Lewis, Richard J; Christie, Macdonald J; Alewood, Paul F

    2016-05-01

    Peptide dendrimers are a novel class of macromolecules of emerging interest with the potential of delayed renal clearance due to their molecular size and enhanced activity due to the multivalency effect. In this work, an active analogue of the disulfide-rich χ-conotoxin χ-MrIA (χ-MrIA), a norepinephrine reuptake (norepinephrine transporter) inhibitor, was grafted onto a polylysine dendron. Dendron decoration was achieved by employing copper-catalyzed alkyne-azide cycloaddition with azido-PEG chain-modified χ-MrIA analogues, leading to homogenous 4-mer and 8-mer χ-MrIA dendrimers with molecular weights ranging from 8 to 22 kDa. These dendrimers were investigated for their impact on peptide secondary structure, in vitro functional activity, and potential anti-allodynia in vivo. NMR studies showed that the χ-MrIA tertiary structure was maintained in the χ-MrIA dendrimers. In a functional norepinephrine transporter reuptake assay, χ-MrIA dendrimers showed slightly increased potency relative to the azido-PEGylated χ-MrIA analogues with similar potency to the parent peptide. In contrast to χ-MrIA, no anti-allodynic action was observed when the χ-MrIA dendrimers were administered intrathecally in a rat model of neuropathic pain, suggesting that the larger dendrimer structures are unable to diffuse through the spinal column tissue and reach the norepinephrine transporter. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  13. The synthesis and characterization of biotin-silver-dendrimer nanocomposites as novel bioselective labels

    Energy Technology Data Exchange (ETDEWEB)

    Maly, J; Lampova, H; Semeradtova, A; Stofik, M [Faculty of Science, University of J E Purkynje, 40096 Usti nad Labem (Czech Republic); Kovacik, L, E-mail: malyjalga@seznam.c [Institute of Cellular Biology and Pathology, First Faculty of Medicine, Charles University in Prague (Czech Republic)

    2009-09-23

    This paper presents a synthesis of a novel nanoparticle label with selective biorecognition properties based on a biotinylated silver-dendrimer nanocomposite (AgDNC). Two types of labels, a biotin-AgDNC (bio-AgDNC) and a biotinylated AgDNC with a poly(ethylene)glycol spacer (bio-PEG-AgDNC), were synthesized from a generation 7 (G7) hydroxyl-terminated ethylenediamine-core-type (2-carbon core) PAMAM dendrimer (DDM) by an N,N'-dicyclohexylcarbodiimide (DDC) biotin coupling and a NaBH{sub 4} silver reduction method. Synthesized conjugates were characterized by several analytical methods, such as UV-vis, FTIR, AFM, TEM, ELISA, HABA assay and SPR. The results show that stable biotinylated nanocomposites can be formed either with internalized silver nanoparticles (AgNPs) in a DMM polymer backbone ('type I') or as externally protected ('type E'), depending on the molar ratio of the silver/DMM conjugate and type of conjugate. Furthermore, the selective biorecognition function of the biotin is not affected by the AgNPs' synthesis step, which allows a potential application of silver nanocomposite conjugates as biospecific labels in various bioanalytical assays, or potentially as fluorescence cell biomarkers. An exploitation of the presented label in the development of electrochemical immunosensors is anticipated.

  14. Influence of dendrimer generation and polyethylene glycol length on the biodistribution of PEGylated dendrimers.

    Science.gov (United States)

    Kojima, Chie; Regino, Celeste; Umeda, Yasuhito; Kobayashi, Hisataka; Kono, Kenji

    2010-01-04

    Dendrimers are a potential drug carrier. Because modification with polyethylene glycol (PEG) is known to improve the blood retention, PEGylated dendrimers have been studied as a useful drug carrier. In this study, three types of PEGylated L-lysine-bearing polyamidoamine dendrimers (PEG2k-Lys-PAMAM (G4), PEG5k-Lys-PAMAM (G4), PEG2k-Lys-PAMAM (G5)) were synthesized, which are composed of a dendrimer of different generations (generations 4 and 5) and PEG chains with different molecular weights (2k and 5k). An acetylated L-lysine-bearing dendrimer was also synthesized as a non-PEGylated dendrimer. Bifunctional diethylenetriaminepentaacetic acid (pSCN-benzyl-DTPA) was bound to the epsilon -amino group of lysine in a dendrimer, to be labeled with radioactive indium-111. These PEGylayed dendrimers showed longer blood retention and lower accumulation in other normal organs such as the kidneys than the non-PEGylated dendrimer. The PEGylated dendrimers with the higher generation and the longer PEG led the greater blood retention.

  15. The vitamin E analog, alpha-tocopheryloxyacetic acid enhances the anti-tumor activity of trastuzumab against HER2/neu-expressing breast cancer

    Directory of Open Access Journals (Sweden)

    Penichet Manuel L

    2011-11-01

    Full Text Available Abstract Background HER2/neu is an oncogene that facilitates neoplastic transformation due to its ability to transduce growth signals in a ligand-independent manner, is over-expressed in 20-30% of human breast cancers correlating with aggressive disease and has been successfully targeted with trastuzumab (Herceptin®. Because trastuzumab alone achieves only a 15-30% response rate, it is now commonly combined with conventional chemotherapeutic drugs. While the combination of trastuzumab plus chemotherapy has greatly improved response rates and increased survival, these conventional chemotherapy drugs are frequently associated with gastrointestinal and cardiac toxicity, bone marrow and immune suppression. These drawbacks necessitate the development of new, less toxic drugs that can be combined with trastuzumab. Recently, we reported that orally administered alpha-tocopheryloxyacetic acid (α-TEA, a novel ether derivative of alpha-tocopherol, dramatically suppressed primary tumor growth and reduced the incidence of lung metastases both in a transplanted and a spontaneous mouse model of breast cancer without discernable toxicity. Methods In this study we examined the effect of α-TEA plus HER2/neu-specific antibody treatment on HER2/neu-expressing breast cancer cells in vitro and in a HER2/neu positive human xenograft tumor model in vivo. Results We show in vitro that α-TEA plus anti-HER2/neu antibody has an increased cytotoxic effect against murine mammary tumor cells and human breast cancer cells and that the anti-tumor effect of α-TEA is independent of HER2/neu status. More importantly, in a human breast cancer xenograft model, the combination of α-TEA plus trastuzumab resulted in faster tumor regression and more tumor-free animals than trastuzumab alone. Conclusion Due to the cancer cell selectivity of α-TEA, and because α-TEA kills both HER2/neu positive and HER2/neu negative breast cancer cells, it has the potential to be effective and

  16. T-DM1, a novel antibody–drug conjugate, is highly effective against primary HER2 overexpressing uterine serous carcinoma in vitro and in vivo

    International Nuclear Information System (INIS)

    English, Diana P; Bellone, Stefania; Schwab, Carlton L; Bortolomai, Ileana; Bonazzoli, Elena; Cocco, Emiliano; Buza, Natalia; Hui, Pei; Lopez, Salvatore; Ratner, Elena; Silasi, Dan-Arin; Azodi, Masoud; Schwartz, Peter E; Rutherford, Thomas J; Santin, Alessandro D

    2014-01-01

    Amplification of c-erbB2 has been reported in over 30% of uterine serous carcinoma (USC) and found to confer poor survival because of high proliferation and increased resistance to therapy. In this study, we evaluated for the first time Trastuzumab emtansine (T-DM1), a novel antibody–drug conjugate, against multiple epidermal growth factor receptor-2 (HER2)-positive USC cells in vitro followed by developing a supportive in vivo model. Fifteen primary USC cell lines were assessed by immunohistochemistry (IHC) and flow cytometry for HER2 protein expression. C-erbB2 gene amplification was evaluated using fluorescent in situ hybridization. Sensitivity to T-DM1 and trastuzumab (T)-induced antibody-dependent cell-mediated cytotoxicity was evaluated in 5-h chromium release assays. T-DM1 and T cytostatic and apoptotic activities were evaluated using flow-cytometry-based proliferation assays. In vivo activity of T-DM1 versus T in USC xenografts in SCID mice was also evaluated. High levels of HER2 protein overexpression and HER2 gene amplification were detected in 33% of USC cell lines. T-DM1 was considerably more effective than trastuzumab in inhibiting cell proliferation and in causing apoptosis (P = 0.004) of USC showing HER2 overexpression. Importantly, T-DM1 was highly active at reducing tumor formation in vivo in USC xenografts overexpressing HER2 (P = 0.04) and mice treated with TDM-1 had significantly longer survival when compared to T-treated mice and control mice (P ≤ 0.0001). T-DM1 shows promising antitumor effect in HER2-positive USC cell lines and USC xenografts and its activity is significantly higher when compared to T. T-DM1 may represent a novel treatment option for HER2-positive USC patients with disease refractory to trastuzumab and traditional chemotherapy

  17. Transepithelial transport of PAMAM dendrimers across isolated rat jejunal mucosae in ussing chambers.

    Science.gov (United States)

    Hubbard, Dallin; Ghandehari, Hamidreza; Brayden, David J

    2014-08-11

    Oral delivery remains a challenge for poorly permeable hydrophilic macromolecules. Poly(amido amine) (PAMAM) dendrimers have shown potential for their possible oral delivery. Transepithelial transport of carboxyl-terminated G3.5 and amine-terminated G4 PAMAM dendrimers was assessed using isolated rat jejunal mucosae mounted in Ussing chambers. The 1 mM FITC-labeled dendrimers were added to the apical side of mucosae. Apparent permeability coefficients (Papp) from the apical to the basolateral side were significantly increased for FITC when conjugated to G3.5 PAMAM dendrimer compared to FITC alone. Minimal signs of toxicity were observed when mucosae were exposed to both dendrimers with respect to transepithelial electrical resistance changes, carbachol-induced short circuit current stimulation, and histological changes. [(14)C]-mannitol fluxes were not altered in the presence of 1 mM dendrimers, suggesting that the paracellular pathway was not affected at this concentration in this model. These results give insight into the mechanism of PAMAM dendrimer transepithelial rat jejunal transport, as well as toxicological considerations important for oral drug delivery.

  18. The interplay of morphology and carrier recombination in dendrimer-based organic photovoltaics.

    Science.gov (United States)

    Shaheen, Sean; Kopidakis, Nikos; Mitchell, William; Rance, William; van de Lagemaat, Jao; Rumbles, Garry

    2007-03-01

    Pi-conjugated dendrimers provide an alternative to polymers in organic photovoltaic devices that allow for systematic study of how the molecular structure affects the morphology of the donor and acceptor components and subsequently how the device operates. The degree of mixing and specific geometry of the donor-acceptor blend play a determining role in the rate of exciton dissociation as well as the efficacy of charge transport out of the active layer. We find that pi-conjugated dendrimers are more miscible with the fullerene-derivative acceptor than their polymeric counterparts, which leads to smaller domains than are commonly found in polymer-fullerene blends. Here we discuss how these differing morphologies affect exciton dissociation, carrier transport, and carrier recombination in the devices.

  19. Enhancement of anti-tumor activity of hybrid peptide in conjugation with carboxymethyl dextran via disulfide linkers.

    Science.gov (United States)

    Gaowa, Arong; Horibe, Tomohisa; Kohno, Masayuki; Tabata, Yasuhiko; Harada, Hiroshi; Hiraoka, Masahiro; Kawakami, Koji

    2015-05-01

    To improve the anti-tumor activity of EGFR2R-lytic hybrid peptide, we prepared peptide-modified dextran conjugates with the disulfide bonds between thiolated carboxymethyl dextran (CMD-Cys) and cysteine-conjugated peptide (EGFR2R-lytic-Cys). In vitro release studies showed that the peptide was released from the CMD-s-s-peptide conjugate in a concentration-dependent manner in the presence of glutathione (GSH, 2μM-2mM). The CMD-s-s-peptide conjugate exhibited a similar cytotoxic activity with free peptide alone against human pancreatic cancer BxPC-3 cells in vitro. Furthermore, it was shown that the CMD-s-s-peptide conjugates were highly accumulated in tumor tissue in a mouse xenograft model using BxPC-3 cells, and the anti-tumor activity of the conjugate was more effective than that of the free peptide. In addition, the plasma concentrations of peptide were moderately increased and the elimination half-life of the peptide was prolonged after intravenous injection of CMD-s-s-peptide conjugates. These results demonstrated that the conjugate based on thiolated CMD polymer would be potentially useful carriers for the sustained release of the hybrid peptide in vivo. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The HER2 CISH pharmDx(™) Kit in the assessment of breast cancer patients for anti-HER2 treatment.

    Science.gov (United States)

    Foged, Niels T; Brügmann, Anja; Jørgensen, Jan T

    2013-04-01

    Testing for amplification of the human EGF receptor 2 (HER2) gene by in situ hybridization is a central principle for the identification of breast cancer patients likely to respond to treatments directed toward HER2. However, its application in clinical routine has been somewhat restricted by the typical use of a visualization system based on fluorescence (FISH), which requires skilled, work-intensive, high-magnification quantitative microscopy. The US FDA has recently approved the HER2 CISH pharmDx™ Kit, which is characterized by employing a chromogenic visualization system that allows quantification of the HER2 gene and centromere 17 reference signals by relatively low-magnification brightfield microscopy. It is indicated as an aid in the assessment of patients for whom Herceptin(®) (trastuzumab) treatment is being considered.

  1. Structure-skin permeability relationship of dendrimers.

    Science.gov (United States)

    Venuganti, Venkata Vamsi; Sahdev, Preety; Hildreth, Michael; Guan, Xiangming; Perumal, Omathanu

    2011-09-01

    To investigate skin penetration of poly (amidoamine) (PAMAM) dendrimers as a function of surface charge and molecular weight in presence and absence of iontophoresis. Dendrimers were labeled with fluoroisothiocynate (FITC); skin penetration of dendrimers was studied using excised porcine skin in-vitro. Skin penetration of FITC-labeled dendrimers was quantified using confocal laser scanning microscope (CLSM). G2-G6 NH(2), G3.5-COOH and G4-OH dendrimers were used. Cationic dendrimers showed higher skin penetration than neutral and anionic dendrimers. Skin penetration of cationic dendrimer increased linearly with increase in treatment time. Iontophoresis enhanced skin penetration of cationic and neutral dendrimers. Increase in current strength and current duration increased skin transport of dendrimers. Passive and iontophoretic skin penetration of cationic dendrimers was inversely related to their molecular weight. Dendrimer penetrated the skin through intercellular lipids and hair follicles. With iontophoresis, dendrimer was also found in localized skin regions. The study demonstrates that the physicochemical properties of dendrimers influence their skin transport. Findings can be used to design dendrimer-based nanocarriers for drug delivery to skin.

  2. Dendrimer-conjugated iron oxide nanoparticles as stimuli-responsive drug carriers for thermally-activated chemotherapy of cancer.

    Science.gov (United States)

    Nigam, Saumya; Bahadur, Dhirendra

    2017-07-01

    In recent years, functional nanomaterials have found an appreciable place in the understanding and treatment of cancer. This work demonstrates the fabrication and characterization of a new class of cationic, biocompatible, peptide dendrimers, which were then used for stabilizing and functionalizing magnetite nanoparticles for combinatorial therapy of cancer. The synthesized peptide dendrimers have an edge over the widely used PAMAM dendrimers due to better biocompatibility and negligible cytotoxicity of their degradation products. The surface engineering efficacy of the peptide dendrimers and their potential use as drug carriers were compared with their PAMAM counterparts. The peptide dendrimer was found to be as efficient as PAMAM dendrimers in its drug-carrying capacity, while its drug release profiles substantially exceeded those of PAMAM's. A dose-dependent study was carried out to assess their half maximal inhibitory concentration (IC 50 ) in vitro with various cancer cell lines. A cervical cancer cell line that was incubated with these dendritic nanoparticles was exposed to alternating current magnetic field (ACMF) to investigate the effect of elevated temperatures on the live cell population. The DOX-loaded formulations, in combination with the ACMF, were also assessed for their synergistic effects on the cancer cells for combinatorial therapy. The results established the peptide dendrimer as an efficient alternative to PAMAM, which can be used successfully in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Rational design of novel, fluorescent, tagged glutamic acid dendrimers with different terminal groups and in silico analysis of their properties

    Directory of Open Access Journals (Sweden)

    Martinho N

    2017-09-01

    Full Text Available Nuno Martinho,1–3 Liana C Silva,1,4 Helena F Florindo,1 Steve Brocchini,2 Mire Zloh,3 Teresa S Barata2 1Research Institute for Medicines (iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; 2Department of Pharmaceutics, UCL School of Pharmacy, London, 3School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UK; 4Centro de Química-Física Molecular and IN – Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal Abstract: Dendrimers are hyperbranched polymers with a multifunctional architecture that can be tailored for the use in various biomedical applications. Peptide dendrimers are particularly relevant for drug delivery applications due to their versatility and safety profile. The overall lack of knowledge of their three-dimensional structure, conformational behavior and structure–activity relationship has slowed down their development. Fluorophores are often conjugated to dendrimers to study their interaction with biomolecules and provide information about their mechanism of action at the molecular level. However, these probes can change dendrimer surface properties and have a direct impact on their interactions with biomolecules and with lipid membranes. In this study, we have used computer-aided molecular design and molecular dynamics simulations to identify optimal topology of a poly(L-glutamic acid (PG backbone dendrimer that allows incorporation of fluorophores in the core with minimal availability for undesired interactions. Extensive all-atom molecular dynamic simulations with the CHARMM force field were carried out for different generations of PG dendrimers with the core modified with a fluorophore (nitrobenzoxadiazole and Oregon Green 488 and various surface groups (glutamic acid, lysine and tryptophan. Analysis of structural and topological features of all designed dendrimers provided information about their size, shape

  4. Pharmacodynamics, pharmacokinetics and clinical efficacy of neratinib in HER2-positive breast cancer and breast cancer with HER2 mutations.

    Science.gov (United States)

    Kourie, Hampig Raphael; Chaix, Marie; Gombos, Andrea; Aftimos, Phillippe; Awada, Ahmad

    2016-08-01

    Despite the availability of several potent HER2-directed targeted agents, primary and acquired resistance continues to influence patient outcomes in HER2-positive breast cancer. Neratinib is an irreversible pan-HER tyrosine kinase inhibitor in late-phase clinical development. This review article focuses on neratinib in the treatment of HER2-positive breast cancer - early and metastatic stage - and HER2-mutant breast cancer, with particular emphasis on the pharmacokinetics and pharmacodynamics of the drug. The phase III ExteNET trial shows that neratinib improves 2-year invasive disease-free survival after trastuzumab-based adjuvant therapy in early-stage HER2-positive breast cancer, and in particular HER2+/HR+ tumors. Survival data are awaited. The investigational role of neratinib in high-risk patients or conversely in de-escalation dual regimens with other anti-HER2 therapies and without chemotherapy are of interest. Phase II trials show that neratinib has efficacy, either as monotherapy or in combination with other chemotherapeutic or endocrine agents, in patients with HER2-positive metastatic breast cancer and in tumors harboring HER2 mutations. The role of neratinib in therapeutic algorithms of HER2-positive patients, as well as delaying CNS events, awaits the results of ongoing trials such as NALA. Diarrhea, the main toxicity of neratinib, can be effectively managed with early loperamide prophylaxis.

  5. Assessment of the systemic distribution of a bioconjugated anti-Her2 magnetic nanoparticle in a breast cancer model by means of magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huerta-Núñez, L. F. E., E-mail: lidi-huerta@hotmail.com [Universidad del Ejercito y FAM/EMGS-Laboratorio Multidisciplinario de Investigación (Mexico); Villanueva-Lopez, G. Cleva, E-mail: villanuevacleva3@gmail.com [Instituto Politécnico Nacional-Escuela Superior de Medicina-Sección Investigación y Posgrado (Mexico); Morales-Guadarrama, A., E-mail: amorales@ci3m.mx [Centro Nacional de Investigacion en Imagenologia e Instrumentacion Medica-Universidad Autónoma (Mexico); Soto, S., E-mail: cuadrosdobles@hotmail.com; López, J., E-mail: jaimelocr@hotmail.com; Silva, J. G., E-mail: gabrielsilva173@gmail.com [Universidad del Ejercito y FAM/EMGS-Laboratorio Multidisciplinario de Investigación (Mexico); Perez-Vielma, N., E-mail: nadiampv@gmail.com [Instituto Politécnico Nacional - Centro Interdisciplinario de Ciencias de la Salud Unidad Santo Tomás (CICS-UST) (Mexico); Sacristán, E., E-mail: esacristan@ci3m.mx [Centro Nacional de Investigacion en Imagenologia e Instrumentacion Medica-Universidad Autónoma (Mexico); Gudiño-Zayas, Marco E., E-mail: gudino@unam.mx [UNAM, Departamento de Medicina Experimental, Facultad de Medicina (Mexico); González, C. A., E-mail: cgonzalezd@ipn.mx [Universidad del Ejercito y FAM/EMGS-Laboratorio Multidisciplinario de Investigación (Mexico)

    2016-09-15

    The aim of this study was to determine the systemic distribution of magnetic nanoparticles of 100 nm diameter (MNPs) coupled to a specific monoclonal antibody anti-Her2 in an experimental breast cancer (BC) model. The study was performed in two groups of Sprague–Dawley rats: control (n = 6) and BC chemically induced (n = 3). Bioconjugated “anti-Her2-MNPs” were intravenously administered, and magnetic resonance imaging (MRI) monitored its systemic distribution at seven times after administration. Non-heme iron presence associated with the location of the bioconjugated anti-Her2-MNPs in splenic, hepatic, cardiac and tumor tissues was detected by Perl’s Prussian blue (PPB) stain. Optical density measurements were used to semiquantitatively determine the iron presence in tissues on the basis of a grayscale values integration of T1 and T2 MRI sequence images. The results indicated a delayed systemic distribution of MNPs in cancer compared to healthy conditions with a maximum concentration of MNPs in cancer tissue at 24 h post-infusion.

  6. Dendrimers as Potential Therapeutic Tools in HIV Inhibition

    Directory of Open Access Journals (Sweden)

    Xiangbo Li

    2013-07-01

    Full Text Available The present treatments for HIV transfection include chemical agents and gene therapies. Although many chemical drugs, peptides and genes have been developed for HIV inhibition, a variety of non-ignorable drawbacks limited the efficiency of these materials. In this review, we discuss the application of dendrimers as both therapeutic agents and non-viral vectors of chemical agents and genes for HIV treatment. On the one hand, dendrimers with functional end groups combine with the gp120 of HIV and CD4 molecule of host cell to suppress the attachment of HIV to the host cell. Some of the dendrimers are capable of intruding into the cell and interfere with the later stages of HIV replication as well. On the other hand, dendrimers are also able to transfer chemical drugs and genes into the host cells, which conspicuously increase the anti-HIV activity of these materials. Dendrimers as therapeutic tools provide a potential treatment for HIV infection.

  7. Dual functions of a new n-type conjugated dendrimer: light-emitting material and additive for polymer electroluminescent devices

    International Nuclear Information System (INIS)

    Park, Jong Hyeok; Kim, Chulhee; Kim, Young Chul

    2009-01-01

    We demonstrate a novel light-emitting diode (LED) of a graded bilayer structure that comprises poly(N-vinylcarbazole) (PVK) with good hole transport ability as the energy donor and a new distyrylanthracene-triazine-based dendrimer with enhanced electron transport ability as the light-emitting molecule. The device contains a graded bilayer structure of the PVK film covered with the dendrimer film prepared by sequential spin-casting of the dendrimer layer from a solvent that only swells the PVK layer. The bilayer device demonstrated a significantly enhanced electoluminescence quantum efficiency compared with the dendrimer single layer device or the PVK : dendrimer blend device with optimized composition. We also prepared composite LEDs with an MEH-PPV : emissive dendrimer blend. By doping the electron-deficient MEH-PPV layer with a small amount of the distyrylanthracene-triazine-based dendrimer, we could not only enhance the device performance but also depress the long-wavelength emission of MEH-PPV.

  8. Dual functions of a new n-type conjugated dendrimer: light-emitting material and additive for polymer electroluminescent devices

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hyeok [Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Chulhee [Hyperstructured Organic Materials Research Center, Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Kim, Young Chul, E-mail: kimyc@khu.ac.k [Department of Chemical Engineering and RIC-CAMID, Kyung Hee University, Yongin-si, Kyunggi-do 499-701 (Korea, Republic of)

    2009-02-07

    We demonstrate a novel light-emitting diode (LED) of a graded bilayer structure that comprises poly(N-vinylcarbazole) (PVK) with good hole transport ability as the energy donor and a new distyrylanthracene-triazine-based dendrimer with enhanced electron transport ability as the light-emitting molecule. The device contains a graded bilayer structure of the PVK film covered with the dendrimer film prepared by sequential spin-casting of the dendrimer layer from a solvent that only swells the PVK layer. The bilayer device demonstrated a significantly enhanced electoluminescence quantum efficiency compared with the dendrimer single layer device or the PVK : dendrimer blend device with optimized composition. We also prepared composite LEDs with an MEH-PPV : emissive dendrimer blend. By doping the electron-deficient MEH-PPV layer with a small amount of the distyrylanthracene-triazine-based dendrimer, we could not only enhance the device performance but also depress the long-wavelength emission of MEH-PPV.

  9. Dual functions of a new n-type conjugated dendrimer: light-emitting material and additive for polymer electroluminescent devices

    Science.gov (United States)

    Hyeok Park, Jong; Kim, Chulhee; Kim, Young Chul

    2009-02-01

    We demonstrate a novel light-emitting diode (LED) of a graded bilayer structure that comprises poly(N-vinylcarbazole) (PVK) with good hole transport ability as the energy donor and a new distyrylanthracene-triazine-based dendrimer with enhanced electron transport ability as the light-emitting molecule. The device contains a graded bilayer structure of the PVK film covered with the dendrimer film prepared by sequential spin-casting of the dendrimer layer from a solvent that only swells the PVK layer. The bilayer device demonstrated a significantly enhanced electoluminescence quantum efficiency compared with the dendrimer single layer device or the PVK : dendrimer blend device with optimized composition. We also prepared composite LEDs with an MEH-PPV : emissive dendrimer blend. By doping the electron-deficient MEH-PPV layer with a small amount of the distyrylanthracene-triazine-based dendrimer, we could not only enhance the device performance but also depress the long-wavelength emission of MEH-PPV.

  10. Poly (amidoamine) dendrimer-mediated hybrid formulation for combination therapy of ramipril and hydrochlorothiazide.

    Science.gov (United States)

    Singh, Mayank Kumar; Pooja, Deep; Kulhari, Hitesh; Jain, Sanjay Kumar; Sistla, Ramakrishna; Chauhan, Abhay Singh

    2017-01-01

    We present a dendrimer-based hybrid formulation strategy to explore the potential of poly (amidoamine) PAMAM dendrimers to be used as drug carriers for combination therapy of an anti-hypertensive drug ramipril (RAPL) and a diuretic hydrochlorothiazide (HCTZ). The drug-dendrimer complexes were prepared by phase-equilibration method. The results showed that the solubility of RAPL and HCTZ was dependent on dendrimer concentration and pH of dendrimer solution. The solubility profile of both RAPL and HCTZ dendrimer complexes illustrated a non-linear relationship with dendrimer concentration. At 0.8% (w/v) dendrimer concentration, solubility of RAPL was increased 4.91 folds with amine-terminated while for HCTZ, solubility enhancement was highest (3.72 folds) with carboxy-terminated. The complexes were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance analysis and high performance liquid chromatography. In-vitro drug dissolution performance of pure drugs, individual drug loaded dendrimer formulations and hybrid formulations was studied in USP dissolution medium (pH7.0) and in simulated gastric fluid (pH1.2). Dendrimer mediated formulations showed faster and complete dissolution compared to pure RAPL or HCTZ. Surprisingly, similar pattern of dissolution profile was established with hybrid formulations as compared to individual drug loaded dendrimers. The dendrimer-based hybrid formulations were found to be stable at dark and refrigerated conditions up to 5weeks. Conclusively, the proposed formulation strategy establishes a novel multitasking platform using dendrimer for simultaneous loading and delivery of multiple drugs for pharmaceutical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Novel approaches to target HER2-positive breast cancer: trastuzumab emtansine

    International Nuclear Information System (INIS)

    Recondo, Gonzalo Jr; Vega, Maximo de la; Galanternik, Fernando; Díaz-Cantón, Enrique; Leone, Bernardo Amadeo; Leone, José Pablo

    2016-01-01

    The human epidermal growth factor receptor 2 (HER2) is overexpressed in 20% of breast carcinomas. Prior to the development of targeted therapies, HER2-positive breast cancer was associated with more aggressive disease and poor prognosis. Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that results from the combination of trastuzumab and DM1, a derivative of the antimicrotubule agent maytansine. This molecule has the ability to enhance cytotoxic drug delivery to specifically targeted cells that overexpress HER2, therefore, maximizing efficacy while sparing toxicity. In recent years, T-DM1 has shown to improve outcomes in metastatic HER2-positive breast cancer that is resistant to trastuzumab. In addition, T-DM1 is currently being tested in the neoadjuvant and adjuvant settings to identify patients who may benefit from this therapy. This review focuses on the mechanism of action, early and late-phase clinical trials, and ongoing studies of T-DM1 in HER2-positive breast cancer

  12. EXAFS Characterization of Dendrimer-Derived Pt/γ-Al2O3

    International Nuclear Information System (INIS)

    Siani, A.; Alexeev, O. S.; Williams, C. T.; Ploehn, H. J.; Amiridis, M. D.

    2007-01-01

    The various steps involved in the preparation of a Pt/γ-Al2O3 material using hydroxyl-terminated generation four (G4OH) PAMAM dendrimers as templates were monitored by EXAFS. The results indicate that Cl ligands in the Pt precursors (H2PtCl6 and K2PtCl4) were partially replaced by aquo ligands upon hydrolysis to form [PtCl3(H2O)3]+ and [PtCl2(H2O)2] species. After interaction of such species with G4OH, Cl ligands from the first coordination shell of Pt were further replaced by nitrogen atoms from the dendrimer interior, indicating the complexation of Pt with the dendrimer. This process was accompanied by a transfer of the electron density from the dendrimer to Pt, indicating that the former plays the role of a ligand. Following treatment of the H2PtCl6/G4OH and K2PtCl4/G4OH composites with NaBH4, no substantial changes were detecteded in the electronic or coordination environment of Pt, and no formation of metal nanoparticles was observed. However, when the reduction treatment was performed with H2, the formation of extremely small Pt clusters incorporating no more than 4 Pt atoms was observed. These Pt species remained strongly bonded to the dendrimer and their nuclearity depends on the length of the H2 treatment. Formation of Pt nanoparticles with an average diameter of approximately 10 A was finally observed after the deposition of H2PtCl6/G4OH on γ-Al2O3 and drying, suggesting that their formation may be related to the collapse of the dendrimer structure. The Pt nanoparticles formed appear to have high mobility, since subsequent thermal treatment in O2/H2 led to further sintering

  13. Formulation and Development of Dendrimer-Based Transdermal ...

    African Journals Online (AJOL)

    Shandong Traditional Chinese Medicine University, Jinan 250012, China ... system for the management of some diseased conditions. Keywords: Dendrimers ... anti-inflammatory and analgesic activity [3]. ..... Cost-effective management of.

  14. Dendrimer-protein interactions versus dendrimer-based nanomedicine.

    Science.gov (United States)

    Shcharbin, Dzmitry; Shcharbina, Natallia; Dzmitruk, Volha; Pedziwiatr-Werbicka, Elzbieta; Ionov, Maksim; Mignani, Serge; de la Mata, F Javier; Gómez, Rafael; Muñoz-Fernández, Maria Angeles; Majoral, Jean-Pierre; Bryszewska, Maria

    2017-04-01

    Dendrimers are hyperbranched polymers belonging to the huge class of nanomedical devices. Their wide application in biology and medicine requires understanding of the fundamental mechanisms of their interactions with biological systems. Summarizing, electrostatic force plays the predominant role in dendrimer-protein interactions, especially with charged dendrimers. Other kinds of interactions have been proven, such as H-bonding, van der Waals forces, and even hydrophobic interactions. These interactions depend on the characteristics of both participants: flexibility and surface charge of a dendrimer, rigidity of protein structure and the localization of charged amino acids at its surface. pH and ionic strength of solutions can significantly modulate interactions. Ligands and cofactors attached to a protein can also change dendrimer-protein interactions. Binding of dendrimers to a protein can change its secondary structure, conformation, intramolecular mobility and functional activity. However, this strongly depends on rigidity versus flexibility of a protein's structure. In addition, the potential applications of dendrimers to nanomedicine are reviwed related to dendrimer-protein interactions. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Immunization with a novel chimeric peptide representing B and T cell epitopes from HER2 extracellular domain (HER2 ECD) for breast cancer.

    Science.gov (United States)

    Mahdavi, Manijeh; Keyhanfar, Mehrnaz; Jafarian, Abbas; Mohabatkar, Hassan; Rabbani, Mohammad

    2014-12-01

    Because of direct stimulating immune system against disease, vaccination or active immunotherapy is preferable compared to passive immunotherapy. For this purpose, a newly designed chimeric peptide containing epitopes for both B and T cells from HER2 ECD subdomain III was proposed. To evaluate the effects of the active immunization, a discontinuous B cell epitope peptide was selected based on average antigenicity by bioinformatics analysis. The selected peptide was collinearly synthesized as a chimera with a T helper epitope from the protein sequence of measles virus fusion (208-302) using the GPSL linker. Three mice were immunized with the chimeric peptide. Reactive antibodies with HER2 protein in ELISA and immunofluorescence assays with no cross-reactivity were generated. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay indicated that the anti-peptide sera had inhibitory effects on proliferation of SK-BR-3 cells. Hence, the newly designed, discontinuous chimeric peptide representing B and T cell epitopes from subdomain III of HER2-ECD can form the basis for future vaccines design, where these data can be applied for monoclonal antibody production targeting the distinct epitope of HER2 receptor compared to the two broadly used anti-HER2 monoclonal antibodies, Herceptin and pertuzumab.

  16. HER2 mutated breast cancer responds to treatment with single agent neratinib, a second generation HER2/EGFR tyrosine kinase inhibitor

    Science.gov (United States)

    Ben–Baruch, Noa Efrat; Bose, Ron; Kavuri, Shyam M.; Ma, Cynthia X.; Ellis, Matthew J.

    2015-01-01

    Activating mutations in the HER2 tyrosine kinase have been identified in human breast cancers that lack HER2 gene amplification. These patients are not candidates for HER2 targeted drugs under current standards of care, but preclinical data strongly suggest that these patients will benefit from anti-HER2 drugs. In this case report, we describe a young woman with metastatic breast cancer whose tumor was found to carry a HER2 L755S mutation, which is in the kinase domain of HER2. Treatment with the second generation HER2/EGFR tyrosine kinase inhibitor, neratinib, resulted in partial response and dramatic improvement in the patient’s function status. This partial response lasted 11 months and when the patient’s cancer progressed, she was treated with neratinib plus capecitabine and her cancer again responded. This second response parallels the benefit seen with continuing trastuzumab in HER2 amplified breast cancer after disease progression. This case is the first report, to our knowledge, of successful single agent treatment of HER2 mutated breast cancer. Two clinical trials of neratinib for HER2 mutated, metastatic breast cancer are currently enrolling patients. Further, data from The Cancer Genome Atlas project have identified HER2 mutations in a wide range of solid tumors, including bladder, colorectal, and non-small cell lung cancer, suggesting that clinical trials of neratinib or neratinib-based combinations for HER2 mutated solid tumors is warranted. PMID:26358790

  17. HER2-Mutated Breast Cancer Responds to Treatment With Single-Agent Neratinib, a Second-Generation HER2/EGFR Tyrosine Kinase Inhibitor.

    Science.gov (United States)

    Ben-Baruch, Noa Efrat; Bose, Ron; Kavuri, Shyam M; Ma, Cynthia X; Ellis, Matthew J

    2015-09-01

    Activating mutations in the HER2 tyrosine kinase have been identified in human breast cancers that lack HER2 gene amplification. These patients are not candidates for HER2-targeted drugs under current standards of care, but preclinical data strongly suggest that these patients will benefit from anti-HER2 drugs. This case report describes a young woman with metastatic breast cancer whose tumor was found to carry a HER2 L755S mutation, which is in the kinase domain of HER2. Treatment with the second-generation HER2/EGFR tyrosine kinase inhibitor neratinib resulted in partial response and dramatic improvement in the patient's functional status. This partial response lasted 11 months, and when the patient's cancer progressed, she was treated with neratinib plus capecitabine and her cancer again responded. This second response parallels the benefit seen with continuing trastuzumab in HER2-amplified breast cancer after disease progression. This case represents the first report, to our knowledge, of successful single-agent treatment of HER2-mutated breast cancer. Two clinical trials of neratinib for HER2-mutated metastatic breast cancer are currently enrolling patients. Further, data from The Cancer Genome Atlas project have identified HER2 mutations in a wide range of solid tumors, including bladder, colorectal, and non-small cell lung cancers, suggesting that clinical trials of neratinib or neratinib-based combinations for HER2-mutated solid tumors is warranted. Copyright © 2015 by the National Comprehensive Cancer Network.

  18. Dual-targeting hybrid nanoparticles for the delivery of SN38 to Her2 and CD44 overexpressed human gastric cancer

    Science.gov (United States)

    Yang, Zhe; Luo, Huiyan; Cao, Zhong; Chen, Ya; Gao, Jinbiao; Li, Yingqin; Jiang, Qing; Xu, Ruihua; Liu, Jie

    2016-06-01

    Gastric cancer (GC), particularly of the type with high expression of both human epidermal growth factor receptor 2 (Her2) and cluster determinant 44 (CD44), is one of the most malignant human tumors which causes a high mortality rate due to rapid tumor growth and metastasis. To develop effective therapeutic treatments, a dual-targeting hybrid nanoparticle (NP) system was designed and constructed to deliver the SN38 agent specifically to human solid gastric tumors bearing excessive Her2 and CD44. The hybrid NPs consist of a particle core made of the biodegradable polymer PLGA and a lipoid shell prepared by conjugating the AHNP peptides and n-hexadecylamine (HDA) to the carboxyl groups of hyaluronic acid (HA). Upon encapsulation of the SN38 agent in the NPs, the AHNP peptides and HA on the NP surface allow preferential delivery of the drug to gastric cancer cells (e.g., HGC27 cells) by targeting Her2 and CD44. Cellular uptake and in vivo biodistribution experiments verified the active targeting and prolonged in vivo circulation properties of the dual-targeting hybrid NPs, leading to enhanced accumulation of the drug in tumors. Furthermore, the anti-proliferation mechanism studies revealed that the inhibition of the growth and invasive activity of HGC27 cells was not only attributed to the enhanced cellular uptake of dual-targeting NPs, but also benefited from the suppression of CD44 and Her2 expression by HA and AHNP moieties. Finally, intravenous administration of the SN38-loaded dual-targeting hybrid NPs induced significant growth inhibition of HGC27 tumor xenografted in nude mice compared with a clinical antitumor agent, Irinotecan (CPT-11), and the other NP formulations. These results demonstrate that the designed dual-targeting hybrid NPs are promising for targeted anti-cancer drug delivery to treat human gastric tumors over-expressing Her2 and CD44.Gastric cancer (GC), particularly of the type with high expression of both human epidermal growth factor receptor

  19. Influence of Alternative Tubulin Inhibitors on the Potency of a Epirubicin-Immunochemotherapeutic Synthesized with an Ultra Violet Light-Activated Intermediate: Influence of incorporating an internal/integral disulfide bond structure and Alternative Tubulin/Microtubule Inhibitors on the Cytotoxic Anti-Neoplastic Potency of Epirubicin-(C3-amide)-Anti-HER2/neu Synthesized Utilizing a UV-Photoactivated Anthracycline Intermediate.

    Science.gov (United States)

    Coyne, C P; Jones, Toni; Bear, Ryan

    2012-11-01

    Immunochemotherapeutics, epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] with an internal disulfide bond, and epirubicin-(C 3 - amide )-[anti-HER2/ neu ] were synthesized utilizing succinimidyl 2-[(4,4'-azipentanamido) ethyl]-1,3'-dithioproprionate or succinimidyl 4,4-azipentanoate respectively. Western blot analysis was used to determine the presence of any immunoglobulin fragmentation or IgG-IgG polymerization. Retained HER2/ neu binding characteristics of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] were validated by cell-ELISA using a mammary adenocarcinoma (SKBr-3) population that highly over-expresses trophic HER2/ neu receptor complexes. Cytotoxic anti-neoplastic potency of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] between epirubicin-equivalent concentrations of 10 -10 M and 10 -6 M was determined by measuring the vitality/proliferation of chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3 cell type). Cytotoxic anti-neoplastic potency of benzimidazoles (albendazole, flubendazole, membendazole) and griseofulvin were assessed between 0-to-2 μg/ml and 0-to-100 μg/ml respectively while mebendazole and griseofulvin were analyzed at fixed concentrations of 0.35 μg/ml and 35 g/ml respectively in dual combination with gradient concentrations of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ]. Cytotoxic anti-neoplastic potency for epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] against chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3) was nearly identical at epirubicin-equivalent concentrations of 10 -10 M and 10 -6 M. The benzimadazoles also possessed cytotoxic anti-neoplastic activity with flubendazole and albendazole being the most and least potent respectively. Similarly, griseofulvin had cytotoxic anti-neoplastic activity and was more potent than

  20. Ligand-Receptor Interaction-Mediated Transmembrane Transport of Dendrimer-like Soft Nanoparticles: Mechanisms and Complicated Diffusive Dynamics.

    Science.gov (United States)

    Liang, Junshi; Chen, Pengyu; Dong, Bojun; Huang, Zihan; Zhao, Kongyin; Yan, Li-Tang

    2016-05-09

    Nearly all nanomedical applications of dendrimer-like soft nanoparticles rely on the functionality of attached ligands. Understanding how the ligands interact with the receptors in cell membrane and its further effect on the cellular uptake of dendrimer-like soft nanoparticles is thereby a key issue for their better application in nanomedicine. However, the essential mechanism and detailed kinetics for the ligand-receptor interaction-mediated transmembrane transport of such unconventional nanoparticles remain poorly elucidated. Here, using coarse-grained simulations, we present the very first study of molecular mechanism and kinetics behaviors for the transmembrane transport of dendrimer-like soft nanoparticles conjugated with ligands. A phase diagram of interaction states is constructed through examining ligand densities and membrane tensions that allows us to identify novel endocytosis mechanisms featured by the direct wrapping and the penetration-extraction vesiculation. The results provide an in-depth insight into the diffusivity of receptors and dendrimer in the membrane plane and demonstrate how the ligand density influences receptor diffusion and uptake kinetics. It is interesting to find that the ligand-conjugated dendrimers present superdiffusive behaviors on a membrane, which is revealed to be driven by the random fluctuation dynamics of the membrane. The findings facilitate our understanding of some recent experimental observations and could establish fundamental principles for the future development of such important nanomaterials for widespread nanomedical applications.

  1. A combinatorial approach of inclusion complexation and dendrimer synthesization for effective targeting EGFR-TK.

    Science.gov (United States)

    Shende, Pravin; Patil, Sampada; Gaud, R S

    2017-07-01

    The aim of the present study was to use a combinatorial approach of inclusion complexation and dendrimer synthesization of gefitinib using solvent-free technique for targeting EGFR-TK to treat Non-Small-Cell Lung Cancer (NSCLC). The inclusion complex of gefitinib with β-cyclodextrin was prepared by trituration method. This complex encapsulated G4 PAMAM dendrimers were synthesized by Michael addition and amidation reactions using green chemistry and then PEGylated by conjugation reaction. FTIR and DSC confirmed the formation of inclusion complex of gefitinib and β-cyclodextrin and PEGylation of G4 PAMAM dendrimers. Gefitinib showed higher solubility, encapsulation efficiency and controlled release profile from PEGylated dendrimers compared to inclusion complex. The PEGylated dendrimers of inclusion complex of gefitinib were found to reduce hemolytic toxicity and lesser GI 50 value on Human lung cancer cell line A-549 by effective targeting EGFR-TK. A combinatorial approach of inclusion complexation and dendrimer synthesization is one of the alternative advanced approaches to treat NSCLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Cardiotoxicity of novel HER2-targeted therapies.

    Science.gov (United States)

    Sendur, Mehmet A N; Aksoy, Sercan; Altundag, Kadri

    2013-08-01

    Trastuzumab, an anti-HER2 humanized monoclonal antibody, is the standard treatment for both early and metastatic HER2-positive breast cancer. In addition to other chemotherapeutic agents, trastuzumab significantly improves response rate and survival in HER2-positive early and metastatic breast cancer. Although it is well known that trastuzumab therapy is closely associated with both symptomatic and asymptomatic cardiotoxicity, less is known about novel HER2-targeted therapies. The aim of this review is to discuss the cardiac safety data from recent studies of novel anti-HER2 drugs other than trastuzumab. Novel HER2-targeted therapies showed favorable results in HER2 positive metastatic breast cancer patients. Pubmed database, ASCO and San Antonio Breast Cancer Symposium Meeting abstracts were searched until January 2013 using the following search keywords; 'trastuzumab, trastuzumab cardiotoxicity, HER-2 targeted therapies, lapatinib, pertuzumab, trastuzumab emtansine, afatinib and neratinib'; papers which were considered relevant for the aim of this review were selected by the authors. Lapatinib, pertuzumab, T-DM1, neratinib and afatinib molecules are evaluated in the study. In a comprehensive analysis, 3689 lapatinib treated patients enrolled in 49 trials; asymptomatic cardiac events were reported in 53 patients (1.4%) and symptomatic grade III and IV systolic dysfunction was observed only in 7 patients (0.2%) treated with lapatinib. In phase I-III trials of pertuzumab, cardiac dysfunction was seen in 4.5-14.5% of patients with pertuzumab treatment and cardiac dysfunction was usually grade I and II. Cardiotoxicity of pertuzumab was usually reported with the trastuzumab combination and no additive cardiotoxicity was reported with addition of pertuzumab to trastuzumab. T-DM1 had a better safety profile compared to trastuzumab, no significant cardiotoxicity was observed with T-DM1 in heavily pre-treated patients. In the EMILIA study, only in 1.7% of patients in the T

  3. Structure of Carbon Nanotube-dendrimer composite

    OpenAIRE

    Vasumathi, V.; Pramanik, Debabrata; Sood, A. K.; Maiti, Prabal K

    2012-01-01

    Using all atomistic molecular dynamics (MD) simulations we report the microscopic picture of the nanotube-dendrimer complex for PAMAM dendrimer of generation 2 to 4 and carbon nanotube of chirality (6,5). We find compact wrapping conformations of dendrimer onto the nanotube surface for all the three generations of PAMAM dendrimer. The degree of wrapping is more for non-protonated dendrimer compared to the protonated dendrimer. For comparison we also study the interaction of another dendrimer,...

  4. On the ability of PAMAM dendrimers and dendrimer/DNA aggregates to penetrate POPC model biomembranes.

    Science.gov (United States)

    Ainalem, Marie-Louise; Campbell, Richard A; Khalid, Syma; Gillams, Richard J; Rennie, Adrian R; Nylander, Tommy

    2010-06-03

    Poly(amido amine) (PAMAM) dendrimers have previously been shown, as cationic condensing agents of DNA, to have high potential for nonviral gene delivery. This study addresses two key issues for gene delivery: the interaction of the biomembrane with (i) the condensing agent (the cationic PAMAM dendrimer) and (ii) the corresponding dendrimer/DNA aggregate. Using in situ null ellipsometry and neutron reflection, parallel experiments were carried out involving dendrimers of generations 2 (G2), 4 (G4), and 6 (G6). The study demonstrates that free dendrimers of all three generations were able to traverse supported palmitoyloleoylphosphatidylcholine (POPC) bilayers deposited on silica surfaces. The model biomembranes were elevated from the solid surfaces upon dendrimer penetration, which offers a promising new way to generate more realistic model biomembranes where the contact with the supporting surface is reduced and where aqueous cavities are present beneath the bilayer. The largest dendrimer (G6) induced partial bilayer destruction directly upon penetration, whereas the smaller dendrimers (G2 and G4) leave the bilayer intact, so we propose that lower generation dendrimers have greater potential as transfection mediators. In addition to the experimental observations, coarse-grained simulations on the interaction between generation 3 (G3) dendrimers and POPC bilayers were performed in the absence and presence of a bilayer-supporting negatively charged surface that emulates the support. The simulations demonstrate that G3 is transported across free-standing POPC bilayers by direct penetration and not by endocytosis. The penetrability was, however, reduced in the presence of a surface, indicating that the membrane transport observed experimentally was not driven solely by the surface. The experimental reflection techniques were also applied to dendrimer/DNA aggregates of charge ratio = 0.5, and while G2/DNA and G4/DNA aggregates interact with POPC bilayers, G6/DNA

  5. Analysis of Biotinylated Generation 4 Poly(amidoamine (PAMAM Dendrimer Distribution in the Rat Brain and Toxicity in a Cellular Model of the Blood-Brain Barrier

    Directory of Open Access Journals (Sweden)

    Heather A. Bullen

    2013-09-01

    Full Text Available Dendrimers are highly customizable nanopolymers with qualities that make them ideal for drug delivery. The high binding affinity of biotin/avidin provides a useful approach to fluorescently label synthesized dendrimer-conjugates in cells and tissues. In addition, biotin may facilitate delivery of dendrimers through the blood-brain barrier (BBB via carrier-mediated endocytosis. The purpose of this research was to: (1 measure toxicity using lactate dehydrogenase (LDH assays of generation (G4 biotinylated and non-biotinylated poly(amidoamine (PAMAM dendrimers in a co-culture model of the BBB, (2 determine distribution of dendrimers in the rat brain, kidney, and liver following systemic administration of dendrimers, and (3 conduct atomic force microscopy (AFM on rat brain sections following systemic administration of dendrimers. LDH measurements showed that biotinylated dendrimers were toxic to cell co-culture after 48 h of treatment. Distribution studies showed evidence of biotinylated and non-biotinylated PAMAM dendrimers in brain. AFM studies showed evidence of dendrimers only in brain tissue of treated rats. These results indicate that biotinylation does not decrease toxicity associated with PAMAM dendrimers and that biotinylated PAMAM dendrimers distribute in the brain. Furthermore, this article provides evidence of nanoparticles in brain tissue following systemic administration of nanoparticles supported by both fluorescence microscopy and AFM.

  6. A novel synergetic targeting strategy for glioma therapy employing borneol combination with angiopep-2-modified, DOX-loaded PAMAM dendrimer.

    Science.gov (United States)

    Han, Shunping; Zheng, Hongyue; Lu, Yanping; Sun, Yue; Huang, Anhao; Fei, Weidong; Shi, Xiaowei; Xu, Xiuling; Li, Jingjing; Li, Fanzhu

    2018-01-01

    Glioma is the most common primary malignant brain tumour and the effect of chemotherapy is hampered by low permeability across the blood-brain-barrier (BBB). Borneol is a time-honoured 'Guide' drug in traditional Chinese medicine and has been proved to be capable of promoting free drugs into the brain efficiently, but there are still risks that free drugs, especially anti-glioma drugs, may be disassembled and metabolised before penetrating the BBB and caused the whole brain distribution. The purpose of this paper was to investigate whether borneol intervention could facilitate the BBB penetration and assist glioma treatment by combining with doxorubicin (DOX) loaded PAMAM dendrimers drug delivery system modified with Angiopep-2 (a ligand of the low-density lipoprotein receptor-related protein, which overexpress both in the BBB and gliomas). The results demonstrated that Angiopep-2 modification could actually enhance the affinity between the dendrimers and the targeting cells and finally increase the cell uptake and boost the anti-tumour ability. Borneol physical combination could further enhance the anti-tumour efficiency of this targeting drug delivery system (TDDS) after penetrating BBB. Compared with free DOX solution, this TDDS illustrated obviously sustained and pH-dependent drug release. This suggested that this synergetic strategy provided a promising way for glioma therapy.

  7. Long-term hazard of recurrence in HER2+ breast cancer patients untreated with anti-HER2 therapy

    DEFF Research Database (Denmark)

    Strasser-Weippl, Kathrin; Horick, Nora; Smith, Ian E

    2015-01-01

    INTRODUCTION: Worldwide, many patients with HER2+ (human epidermal growth factor receptor 2-positive) early breast cancer (BC) do not receive adjuvant trastuzumab. Hazards of recurrence of these patients with respect to hormone receptor status of the primary tumor have not been described. METHODS...

  8. HER2-targeted liposomal doxorubicin displays enhanced anti-tumorigenic effects without associated cardiotoxicity

    International Nuclear Information System (INIS)

    Reynolds, Joseph G.; Geretti, Elena; Hendriks, Bart S.; Lee, Helen; Leonard, Shannon C.; Klinz, Stephan G.; Noble, Charles O.; Lücker, Petra B.; Zandstra, Peter W.; Drummond, Daryl C.; Olivier, Kenneth J.; Nielsen, Ulrik B.; Niyikiza, Clet; Agresta, Samuel V.; Wickham, Thomas J.

    2012-01-01

    Anthracycline-based regimens are a mainstay of early breast cancer therapy, however their use is limited by cardiac toxicity. The potential for cardiotoxicity is a major consideration in the design and development of combinatorial therapies incorporating anthracyclines and agents that target the HER2-mediated signaling pathway, such as trastuzumab. In this regard, HER2-targeted liposomal doxorubicin was developed to provide clinical benefit by both reducing the cardiotoxicity observed with anthracyclines and enhancing the therapeutic potential of HER2-based therapies that are currently available for HER2-overexpressing cancers. While documenting the enhanced therapeutic potential of HER2-targeted liposomal doxorubicin can be done with existing models, there has been no validated human cardiac cell-based assay system to rigorously assess the cardiotoxicity of anthracyclines. To understand if HER2-targeting of liposomal doxorubicin is possible with a favorable cardiac safety profile, we applied a human stem cell-derived cardiomyocyte platform to evaluate the doxorubicin exposure of human cardiac cells to HER2-targeted liposomal doxorubicin. To the best of our knowledge, this is the first known application of a stem cell-derived system for evaluating preclinical cardiotoxicity of an investigational agent. We demonstrate that HER2-targeted liposomal doxorubicin has little or no uptake into human cardiomyocytes, does not inhibit HER2-mediated signaling, results in little or no evidence of cardiomyocyte cell death or dysfunction, and retains the low penetration into heart tissue of liposomal doxorubicin. Taken together, this data ultimately led to the clinical decision to advance this drug to Phase I clinical testing, which is now ongoing as a single agent in HER2-expressing cancers. -- Highlights: ► Novel approach using stem cell-derived cardiomyocytes to assess preclinical safety. ► HER2-targeted liposomal doxorubicin has improved safety profile vs free doxorubicin

  9. HER2-targeted liposomal doxorubicin displays enhanced anti-tumorigenic effects without associated cardiotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Joseph G.; Geretti, Elena; Hendriks, Bart S.; Lee, Helen; Leonard, Shannon C.; Klinz, Stephan G.; Noble, Charles O. [Merrimack Pharmaceuticals, 1 Kendall Square, Suite B7201, Cambridge, MA 02139 (United States); Lücker, Petra B.; Zandstra, Peter W. [University of Toronto, 160 College Street, Office 1116, Toronto, Ontario M5S 3E1 (Canada); Drummond, Daryl C.; Olivier, Kenneth J.; Nielsen, Ulrik B.; Niyikiza, Clet; Agresta, Samuel V. [Merrimack Pharmaceuticals, 1 Kendall Square, Suite B7201, Cambridge, MA 02139 (United States); Wickham, Thomas J., E-mail: twickham@merrimackpharma.com [Merrimack Pharmaceuticals, 1 Kendall Square, Suite B7201, Cambridge, MA 02139 (United States)

    2012-07-01

    Anthracycline-based regimens are a mainstay of early breast cancer therapy, however their use is limited by cardiac toxicity. The potential for cardiotoxicity is a major consideration in the design and development of combinatorial therapies incorporating anthracyclines and agents that target the HER2-mediated signaling pathway, such as trastuzumab. In this regard, HER2-targeted liposomal doxorubicin was developed to provide clinical benefit by both reducing the cardiotoxicity observed with anthracyclines and enhancing the therapeutic potential of HER2-based therapies that are currently available for HER2-overexpressing cancers. While documenting the enhanced therapeutic potential of HER2-targeted liposomal doxorubicin can be done with existing models, there has been no validated human cardiac cell-based assay system to rigorously assess the cardiotoxicity of anthracyclines. To understand if HER2-targeting of liposomal doxorubicin is possible with a favorable cardiac safety profile, we applied a human stem cell-derived cardiomyocyte platform to evaluate the doxorubicin exposure of human cardiac cells to HER2-targeted liposomal doxorubicin. To the best of our knowledge, this is the first known application of a stem cell-derived system for evaluating preclinical cardiotoxicity of an investigational agent. We demonstrate that HER2-targeted liposomal doxorubicin has little or no uptake into human cardiomyocytes, does not inhibit HER2-mediated signaling, results in little or no evidence of cardiomyocyte cell death or dysfunction, and retains the low penetration into heart tissue of liposomal doxorubicin. Taken together, this data ultimately led to the clinical decision to advance this drug to Phase I clinical testing, which is now ongoing as a single agent in HER2-expressing cancers. -- Highlights: ► Novel approach using stem cell-derived cardiomyocytes to assess preclinical safety. ► HER2-targeted liposomal doxorubicin has improved safety profile vs free doxorubicin

  10. Synthesis of New Functionalized Citric Acid-based Dendrimers as Nanocarrier Agents for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Sanaz Motamedi

    2011-06-01

    Full Text Available Introduction: Citric acid-polyethylene glycol-citric acid (CPEGC triblock dendrimers can serve as potential delivery systems. Methods: In this investigation, CPEGC triblock dendrimers were synthesized and then imidazole groups were conjugated onto the surface of the G1, G2 and G3 of the obtained dendrimers. In order to study the type of the interactions between the functionalized dendrimers and a drug molecule, Naproxen which contains acidic groups, was examined as a hydrophobic drug in which the interactions would be of the electrostatic kind between its acidic groups and the lone pair electrons of nitrogen atom in imidazole groups. The quantity of the trapped drug and also the amount of its release were measured with UV spectrometric method in pH 1, 7.4 and 10. The average diameter of the nanocarriers was measured by Dynamic Light Scattering (DLS technique Results: The size range of particles was determined to be 16-50 nm for different generations. The rate of the release increased in pH=10 in all generations due to the increase in Naproxen solubility and the hydrolysis of the esteric bonds in the mentioned pH. The results showed that the amount of the trapped drug increased with the increase in the generation of the dendrimer and pH. Conclusion: Based on our findings, we suggest CPEGC triblock dendrimers possess great potential to be used as drug/gene delivery system.

  11. Phase I Study of 68Ga-HER2-Nanobody for PET/CT Assessment of HER2 Expression in Breast Carcinoma.

    Science.gov (United States)

    Keyaerts, Marleen; Xavier, Catarina; Heemskerk, Johannes; Devoogdt, Nick; Everaert, Hendrik; Ackaert, Chloé; Vanhoeij, Marian; Duhoux, Francois P; Gevaert, Thierry; Simon, Philippe; Schallier, Denis; Fontaine, Christel; Vaneycken, Ilse; Vanhove, Christian; De Greve, Jacques; Lamote, Jan; Caveliers, Vicky; Lahoutte, Tony

    2016-01-01

    Human epidermal growth factor receptor 2 (HER2) status is one of the major tumor characteristics in breast cancer to guide therapy. Anti-HER2 treatment has clear survival advantages in HER2-positive breast carcinoma patients. Heterogeneity in HER2 expression between primary tumor and metastasis has repeatedly been described, resulting in the need to reassess HER2 status during the disease course. To avoid repeated biopsy with potential bias due to tumor heterogeneity, Nanobodies directed against HER2 have been developed as probes for molecular imaging. Nanobodies, which are derived from unique heavy-chain-only antibodies, are the smallest antigen-binding antibody fragments and have ideal characteristics for PET imaging. The primary aims were assessment of safety, biodistribution, and dosimetry. The secondary aim was to investigate tumor-targeting potential. In total, 20 women with primary or metastatic breast carcinoma (score of 2+ or 3+ on HER2 immunohistochemical assessment) were included. Anti-HER2-Nanobody was labeled with (68)Ga via a NOTA derivative. Administered activities were 53-174 MBq (average, 107 MBq). PET/CT scans for dosimetry assessment were obtained at 10, 60, and 90 min after administration. Physical evaluation and blood analysis were performed for safety evaluation. Biodistribution was analyzed for 11 organs using MIM software; dosimetry was assessed using OLINDA/EXM. Tumor-targeting potential was assessed in primary and metastatic lesions. No adverse reactions occurred. A fast blood clearance was observed, with only 10% of injected activity remaining in the blood at 1 h after injection. Uptake was seen mainly in the kidneys, liver, and intestines. The effective dose was 0.043 mSv/MBq, resulting in an average of 4.6 mSv per patient. The critical organ was the urinary bladder wall, with a dose of 0.406 mGy/MBq. In patients with metastatic disease, tracer accumulation well above the background level was demonstrated in most identified sites of

  12. Interaction of phosphorus dendrimers with HIV peptides—Fluorescence studies of nano-complexes formation

    Energy Technology Data Exchange (ETDEWEB)

    Ciepluch, Karol, E-mail: ciepluch@biol.uni.lodz.pl [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland); Ionov, Maksim [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 Route de Narbonne, F-31077 Toulouse cedex 4 (France); Muñoz-Fernández, Maria Angeles [Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Bryszewska, Maria [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska Street 141/143, 90-236 Lodz (Poland)

    2014-04-15

    In this study, dendrimers emerge as an alternative approach for delivery of HIV peptides to dendritic cells. Gp160, NH-EIDNYTNTIYTLLEE-COOH; P24, NH-DTINEEAAEW-COOH and Nef, NHGMDDPEREVLEWRFDSRLAF-COOH peptides were complexed with two types of positively charged phosphorus-containing dendrimers (CPD). Fluorescence polarization, dynamic light scattering, transmission and electron microscopy (TEM) techniques were chosen to evaluate the dendriplexes stability. We were able to show that complexes were stable in time and temperature. This is crucial for using these peptide/dendrimer nano-complexes in a new vaccine against HIV-1 infection. -- Highlights: • The phosphorus dendrimers as nanocarriers of HIV-peptides are proposed. • The complexes of dendrimers and HIV-peptides were stable in time, temperature. • The results convince that phosphorus dendrimers could be consider as anti-HIV vaccine candidates.

  13. Interaction of phosphorus dendrimers with HIV peptides—Fluorescence studies of nano-complexes formation

    International Nuclear Information System (INIS)

    Ciepluch, Karol; Ionov, Maksim; Majoral, Jean-Pierre; Muñoz-Fernández, Maria Angeles; Bryszewska, Maria

    2014-01-01

    In this study, dendrimers emerge as an alternative approach for delivery of HIV peptides to dendritic cells. Gp160, NH-EIDNYTNTIYTLLEE-COOH; P24, NH-DTINEEAAEW-COOH and Nef, NHGMDDPEREVLEWRFDSRLAF-COOH peptides were complexed with two types of positively charged phosphorus-containing dendrimers (CPD). Fluorescence polarization, dynamic light scattering, transmission and electron microscopy (TEM) techniques were chosen to evaluate the dendriplexes stability. We were able to show that complexes were stable in time and temperature. This is crucial for using these peptide/dendrimer nano-complexes in a new vaccine against HIV-1 infection. -- Highlights: • The phosphorus dendrimers as nanocarriers of HIV-peptides are proposed. • The complexes of dendrimers and HIV-peptides were stable in time, temperature. • The results convince that phosphorus dendrimers could be consider as anti-HIV vaccine candidates

  14. Curcumin Conjugated with PLGA Potentiates Sustainability, Anti-Proliferative Activity and Apoptosis in Human Colon Carcinoma Cells

    Science.gov (United States)

    Waghela, Bhargav N.; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M.; Pathak, Chandramani

    2015-01-01

    Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy. PMID:25692854

  15. Silencing of the HER2/neu Gene by siRNA Inhibits Proliferation and Induces Apoptosis in HER2/neu-Overexpressing Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Timo Faltus

    2004-11-01

    Full Text Available In eukaryotes, double-stranded (ds RNA induces sequence-specific inhibition of gene expression referred to as RNA interference (RNAi. We exploited RNAi to define the role of HER2/neu in the neoplastic proliferation of human breast cancer cells. We transfected SK-BR-3, BT-474, MCF-7, and MDA-MB-468 breast cancer cells with short interfering RNA (siRNA targeted against human HER2/neu and analyzed the specific inhibition of HER2/neu expression by Northern and Western blots. Transfection with HER2/neu-specific siRNA resulted in a sequence-specific decrease in HER2/neu mRNA and protein levels. Moreover, transfection with HER2/neu siRNA caused cell cycle arrest at G0/G1 in the breast cancer cell lines SKBR-3 and BT-474, consistent with a powerful RNA silencing effect. siRNA treatment resulted in an antiproliferative and apoptotic response in cells overexpressing HER2/neu, but had no influence in cells with almost no expression of HER2/neu proteins like MDA-MB-468 cells. These data indicate that HER2/neu function is essential for the proliferation of HER2/neuoverexpressing breast cancer cells. Our observations suggest that siRNA targeted against human HER2/neu may be valuable tools as anti proliferative agents that display activity against neoplastic cells at very low doses.

  16. [{sup 18}F]FBEM-Z{sub HER2:342}-Affibody molecule - a new molecular tracer for in vivo monitoring of HER2 expression by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kramer-Marek, Gabriela; Lee, Sang Bong; Capala, Jacek [National Institutes of Health, National Cancer Institute, Bethesda, MD (United States); Kiesewetter, Dale O.; Jagoda, Elaine [National Institutes of Health, National Institute of Biomedical Imaging and Bioengineering, Bethesda, MD (United States); Martiniova, Lucia [National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, MD (United States)

    2008-05-15

    The expression of human epidermal growth factor receptor-2 (HER2) receptors in cancers is correlated with a poor prognosis. If assessed in vivo, it could be used for selection of appropriate therapy for individual patients and for monitoring of the tumor response to targeted therapies. We have radiolabeled a HER2-binding Affibody molecule with fluorine-18 for in vivo monitoring of the HER2 expression by positron emission tomography (PET). The HER2-binding Z{sub HER2:342}-Cys Affibody molecule was conjugated with N-2-(4-[{sup 18}F]fluorobenzamido)ethylmaleimide ([{sup 18}F]FBEM). The in vitro binding of the resulting radioconjugate was characterized by receptor saturation and competition assays. For in vivo studies, the radioconjugate was injected into the tail vein of mice bearing subcutaneous HER2-positive or HER2-negative tumors. Some of the mice were pre-treated with non-labeled Z{sub HER2:342}-Cys. The animals were sacrificed at different times post-injection, and the radioactivity in selected tissues was measured. PET images were obtained using an animal PET scanner. In vitro experiments indicated specific, high-affinity binding to HER2. PET imaging revealed a high accumulation of the radioactivity in the tumor as early as 20 min after injection, with a plateau being reached after 60 min. These results were confirmed by biodistribution studies demonstrating that, as early as 1 h post-injection, the tumor to blood concentration ratio was 7.5 and increased to 27 at 4 h. Pre-saturation of the receptors with unlabeled Z{sub HER2:342}-Cys lowered the accumulation of radioactivity in HER2-positive tumors to the levels observed in HER2-negative ones. Our results suggest that the [{sup 18}F]FBEM-Z{sub HER2:342} radioconjugate can be used to assess HER2 expression in vivo. (orig.)

  17. Synthesis and stability test of radiogadolinium(III-DOTA-PAMAM G3.0-trastuzumab as SPECT-MRI molecular imaging agent for diagnosis of HER-2 positive breast cancer

    Directory of Open Access Journals (Sweden)

    Hardiani Rahmania

    2015-01-01

    Full Text Available Nonivasive diagnosis of cancer can be provided by molecular imaging using hybrid modality to obtain better sensitivity, specificity and depiction localization of the disease. In this study, we developed a new molecular imaging agent, radiogadolinium(III-DOTA-PAMAM G3.0-trastuzumab in the form of 147Gd-DOTA-PAMAM G3.0-trastuzumab, that can be both target-specific radiopharmaceutical in SPECT as well as targeted contrast agent in MRI for the purpose of diagnosis of HER-2 positive breast cancer. 147Gd radionuclide emits γ-rays that can be used in SPECT modality, but because of technical constraint, 147Gd radionuclide was simulated by its radioisotope, 153Gd. Gd-DOTA complex has also been known as good MRI contrast agent. PAMAM G3.0 is useful to concentrate Gd-DOTA compelexes in large quantities, thus minimizing the number of trastuzumab molecules used. Trastuzumab is human monoclonal antibody that can spesifically interact with HER-2. Synthesis of radiogadolinium(III-DOTA-PAMAM G3.0-trastuzumab was initiated by conjugating DOTA NHS ester ligand with PAMAM G3.0 dendrimer. The DOTA-PAMAM G3.0 produced was conjugated to trastuzumab molecule and labeled with 153Gd. Characterization DOTA-PAMAM G3.0-trastuzumab immunoconjugate was performed using HPLC system equipped with SEC. The formation of immunoconjugate was indicated by the shorter retention time (6.82 min compared to that of trastuzumab (7.06 min. Radiochemical purity of radiogadolinium(III-DOTA-PAMAM G3.0-trastuzumab was >99% after purification process by PD-10 desalting column. Radiogadolinium(III-DOTA-PAMAM G3.0-trastuzumab compound was stable at room temperature and at 2–8 0C as indicated by its radiochemical purity 97.6 ± 0.5%–99.1 ± 0.5% after 144 h storage.

  18. Poly(amidoamine) dendrimers on lipid bilayers II: Effects of bilayer phase and dendrimer termination.

    Science.gov (United States)

    Kelly, Christopher V; Leroueil, Pascale R; Orr, Bradford G; Banaszak Holl, Mark M; Andricioaei, Ioan

    2008-08-07

    The molecular structures and enthalpy release of poly(amidoamine) (PAMAM) dendrimers binding to 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) bilayers were explored through atomistic molecular dynamics. Three PAMAM dendrimer terminations were examined: protonated primary amine, neutral acetamide, and deprotonated carboxylic acid. Fluid and gel lipid phases were examined to extract the effects of lipid tail mobility on the binding of generation-3 dendrimers, which are directly relevant to the nanoparticle interactions involving lipid rafts, endocytosis, lipid removal, and/or membrane pores. Upon binding to gel phase lipids, dendrimers remained spherical, had a constant radius of gyration, and approximately one-quarter of the terminal groups were in close proximity to the lipids. In contrast, upon binding to fluid phase bilayers, dendrimers flattened out with a large increase in their asphericity and radii of gyration. Although over twice as many dendrimer-lipid contacts were formed on fluid versus gel phase lipids, the dendrimer-lipid interaction energy was only 20% stronger. The greatest enthalpy release upon binding was between the charged dendrimers and the lipid bilayer. However, the stronger binding to fluid versus gel phase lipids was driven by the hydrophobic interactions between the inner dendrimer and lipid tails.

  19. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells

    Directory of Open Access Journals (Sweden)

    Isabel Correa

    2018-03-01

    Full Text Available Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1 specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires.

  20. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells.

    Science.gov (United States)

    Correa, Isabel; Ilieva, Kristina M; Crescioli, Silvia; Lombardi, Sara; Figini, Mariangela; Cheung, Anthony; Spicer, James F; Tutt, Andrew N J; Nestle, Frank O; Karagiannis, Panagiotis; Lacy, Katie E; Karagiannis, Sophia N

    2018-01-01

    Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα) as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1) specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs) were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires.

  1. Evaluation of Antigen-Conjugated Fluorescent Beads to Identify Antigen-Specific B Cells

    Science.gov (United States)

    Correa, Isabel; Ilieva, Kristina M.; Crescioli, Silvia; Lombardi, Sara; Figini, Mariangela; Cheung, Anthony; Spicer, James F.; Tutt, Andrew N. J.; Nestle, Frank O.; Karagiannis, Panagiotis; Lacy, Katie E.; Karagiannis, Sophia N.

    2018-01-01

    Selection of single antigen-specific B cells to identify their expressed antibodies is of considerable interest for evaluating human immune responses. Here, we present a method to identify single antibody-expressing cells using antigen-conjugated fluorescent beads. To establish this, we selected Folate Receptor alpha (FRα) as a model antigen and a mouse B cell line, expressing both the soluble and the membrane-bound forms of a human/mouse chimeric antibody (MOv18 IgG1) specific for FRα, as test antibody-expressing cells. Beads were conjugated to FRα using streptavidin/avidin-biotin bridges and used to select single cells expressing the membrane-bound form of anti-FRα. Bead-bound cells were single cell-sorted and processed for single cell RNA retrotranscription and PCR to isolate antibody heavy and light chain variable regions. Variable regions were then cloned and expressed as human IgG1/k antibodies. Like the original clone, engineered antibodies from single cells recognized native FRα. To evaluate whether antigen-coated beads could identify specific antibody-expressing cells in mixed immune cell populations, human peripheral blood mononuclear cells (PBMCs) were spiked with test antibody-expressing cells. Antigen-specific cells could comprise up to 75% of cells selected with antigen-conjugated beads when the frequency of the antigen-positive cells was 1:100 or higher. In PBMC pools, beads conjugated to recombinant antigens FRα and HER2 bound antigen-specific anti-FRα MOv18 and anti-HER2 Trastuzumab antibody-expressing cells, respectively. From melanoma patient-derived B cells selected with melanoma cell line-derived protein-coated fluorescent beads, we generated a monoclonal antibody that recognized melanoma antigen-coated beads. This approach may be further developed to facilitate analysis of B cells and their antibody profiles at the single cell level and to help unravel humoral immune repertoires. PMID:29628923

  2. Virus-like particle display of HER2 induces potent anti-cancer responses

    DEFF Research Database (Denmark)

    Palladini, Arianna; Thrane, Susan; Janitzek, Christoph M

    2018-01-01

    Overexpression of human epidermal growth factor receptor-2 (HER2) occurs in 20-30% of invasive breast cancers. Monoclonal antibody therapy is effective in treating HER2-driven mammary carcinomas, but its utility is limited by high costs, side effects and development of resistance. Active vaccinat...

  3. Which Dendrimer to Attain the Desired Properties? Focus on Phosphorhydrazone Dendrimers.

    Science.gov (United States)

    Caminade, Anne-Marie; Majoral, Jean-Pierre

    2018-03-09

    Among the six Critical Nanoscale Design Parameters (CNDPs) proposed by Prof. Donald A. Tomalia, this review illustrates the influence of the sixth one, which concerns the elemental composition, on the properties of dendrimers. After a large introduction that summarizes different types of dendrimers that have been compared with PolyAMidoAMine (PAMAM) dendrimers, this review will focus on the properties of positively and negatively charged phosphorhydrazone (PPH) dendrimers, especially in the field of biology, compared with other types of dendrimers, in particular PAMAM dendrimers, as well as polypropyleneimine (PPI), carbosilane, and p-Lysine dendrimers.

  4. Methotrexate loaded polyether-copolyester dendrimers for the treatment of gliomas: enhanced efficacy and intratumoral transport capability.

    Science.gov (United States)

    Dhanikula, Renu Singh; Argaw, Anteneh; Bouchard, Jean-Francois; Hildgen, Patrice

    2008-01-01

    Therapeutic benefit in glial tumors is often limited due to low permeability of delivery systems across the blood-brain barrier (BBB), drug resistance, and poor penetration into the tumor tissue. In an attempt to overcome these hurdles, polyether-copolyester (PEPE) dendrimers were evaluated as drug carriers for the treatment of gliomas. Dendrimers were conjugated to d-glucosamine as the ligand for enhancing BBB permeability and tumor targeting. The efficacy of methotrexate (MTX)-loaded dendrimers was established against U87 MG and U 343 MGa cells. Permeability of rhodamine-labeled dendrimers and MTX-loaded dendrimers across the in vitro BBB model and their distribution into avascular human glioma tumor spheroids was also studied. Glucosylated dendrimers were found to be endocytosed in significantly higher amounts than nonglucosylated dendrimers by both the cell lines. IC 50 of MTX after loading in dendrimers was lower than that of the free MTX, suggesting that loading MTX in PEPE dendrimers increased its potency. Similar higher activity of MTX-loaded glucosylated and nonglucosylated dendrimers was found in the reduction of tumor spheroid size. These MTX-loaded dendrimers were able to kill even MTX-resistant cells highlighting their ability to overcome MTX resistance. In addition, the amount of MTX-transported across BBB was three to five times more after loading in the dendrimers. Glucosylation further increased the cumulative permeation of dendrimers across BBB and hence increased the amount of MTX available across it. Glucosylated dendrimers distributed through out the avascular tumor spheroids within 6 h, while nonglucosylated dendrimers could do so in 12 h. The results show that glucosamine can be used as an effective ligand not only for targeting glial tumors but also for enhanced permeability across BBB. Thus, glucosylated PEPE dendrimers can serve as potential delivery system for the treatment of gliomas.

  5. Emerging treatments for HER2-positive early-stage breast cancer: focus on neratinib.

    Science.gov (United States)

    Kourie, Hampig Raphael; El Rassy, Elie; Clatot, Florian; de Azambuja, Evandro; Lambertini, Matteo

    2017-01-01

    Over the last decades, a better understanding of breast cancer heterogeneity provided tools for a biologically based personalization of anticancer treatments. In particular, the overexpression of the human epidermal growth factor receptor 2 (HER2) by tumor cells provided a specific target in these HER2-positive tumors. The development of the monoclonal antibody trastuzumab, and its approval in 1998 for the treatment of patients with metastatic disease, radically changed the natural history of this aggressive subtype of breast cancer. These findings provided strong support for the continuous research in targeting the HER2 pathway and implementing the development of new anti-HER2 targeted agents. Besides trastuzumab, a series of other anti-HER2 agents have been developed and are currently being explored for the treatment of breast cancer patients, including those diagnosed with early-stage disease. Among these agents, neratinib, an oral tyrosine kinase inhibitor that irreversibly inhibits HER1, HER2, and HER4 at the intracellular level, has shown promising results, including when administered to patients previously exposed to trastuzumab-based treatment. This article aims to review the available data on the role of the HER2 pathway in breast cancer and on the different targeted agents that have been studied or are currently under development for the treatment of patients with early-stage HER2-positive disease with a particular focus on neratinib.

  6. Intratumoral delivery of CpG-conjugated anti-MUC1 antibody enhances NK cell anti-tumor activity.

    Science.gov (United States)

    Schettini, Jorge; Kidiyoor, Amritha; Besmer, Dahlia M; Tinder, Teresa L; Roy, Lopamudra Das; Lustgarten, Joseph; Gendler, Sandra J; Mukherjee, Pinku

    2012-11-01

    Monoclonal antibodies (mAbs) against tumor-associated antigens are useful anticancer agents. Antibody-dependent cellular cytotoxicity (ADCC) is one of the major mechanisms responsible for initiating natural killer cell (NK)-mediated killing of tumors. However, the regulation of ADCC via NK cells is poorly understood. We have investigated the cytolytic activity of NK cells against pancreatic cancer cells that were coated with an antibody directed against the human tumor antigen, Mucin-1 designated HMFG-2, either alone or conjugated to CpG oligodeoxynucleotide (CpG ODN). Conjugated antibodies were tested for their ability to elicit ADCC in vitro and in vivo against pancreatic cancer cells. NK cells cultured in the presence of immobilized CpG ODN, HMFG-2 Ab, or CpG ODN-conjugated HMFG-2 Ab were able to up-regulate perforin similarly. Interestingly, a significant higher ADCC was observed when CpG ODN-conjugated HMFG-2-coated tumor cells were co-cultured with NK cells compared to unconjugated HMFG-2 Ab or CpG ODN alone. Moreover, MyD88-deficient NK cells can perform ADCC in vitro. Furthermore, intratumoral injections of CpG ODN-conjugated HMFG-2 induced a significant reduction in tumor burden in vivo in an established model of pancreatic tumor in nude mice compared to CpG ODN or the HMFG-2 alone. Depletion of macrophages or NK cells before treatment confirmed that both cells were required for the anti-tumor response in vivo. Results also suggest that CpG ODN and HMFG-2 Ab could be sensed by NK cells on the mAb-coated tumor cells triggering enhanced ADCC in vitro and in vivo.

  7. Dendrimer-Encapsulated Ruthenium Nanoparticles as Catalysts for Lithium-O2 Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Priyanka; Nasybulin, Eduard N.; Engelhard, Mark H.; Kovarik, Libor; Bowden, Mark E.; Li, Shari; Gaspar, Daniel J.; Xu, Wu; Zhang, Jiguang

    2014-12-01

    Dendrimer-encapsulated ruthenium nanoparticles (DEN-Ru) have been used as catalysts in lithium-O2 batteries for the first time. Results obtained from UV-vis spectroscopy, electron microscopy and X-ray photoelectron spectroscopy show that the nanoparticles synthesized by the dendrimer template method are ruthenium oxide instead of metallic ruthenium reported earlier by other groups. The DEN-Ru significantly improve the cycling stability of lithium (Li)-O2 batteries with carbon black electrodes and decrease the charging potential even at low catalyst loading. The monodispersity, porosity and large number of surface functionalities of the dendrimer template prevent the aggregation of the ruthenium nanoparticles making their entire surface area available for catalysis. The potential of using DEN-Ru as stand-alone cathode materials for Li-O2 batteries is also explored.

  8. Which Dendrimer to Attain the Desired Properties? Focus on Phosphorhydrazone Dendrimers

    Directory of Open Access Journals (Sweden)

    Anne-Marie Caminade

    2018-03-01

    Full Text Available Among the six Critical Nanoscale Design Parameters (CNDPs proposed by Prof. Donald A. Tomalia, this review illustrates the influence of the sixth one, which concerns the elemental composition, on the properties of dendrimers. After a large introduction that summarizes different types of dendrimers that have been compared with PolyAMidoAMine (PAMAM dendrimers, this review will focus on the properties of positively and negatively charged phosphorhydrazone (PPH dendrimers, especially in the field of biology, compared with other types of dendrimers, in particular PAMAM dendrimers, as well as polypropyleneimine (PPI, carbosilane, and p-Lysine dendrimers.

  9. Recent advances in dendrimer-based nanovectors for tumor-targeted drug and gene delivery

    Science.gov (United States)

    Kesharwani, Prashant; Iyer, Arun K.

    2015-01-01

    Advances in the application of nanotechnology in medicine have given rise to multifunctional smart nanocarriers that can be engineered with tunable physicochemical characteristics to deliver one or more therapeutic agent(s) safely and selectively to cancer cells, including intracellular organelle-specific targeting. Dendrimers having properties resembling biomolecules, with well-defined 3D nanopolymeric architectures, are emerging as a highly attractive class of drug and gene delivery vector. The presence of numerous peripheral functional groups on hyperbranched dendrimers affords efficient conjugation of targeting ligands and biomarkers that can recognize and bind to receptors overexpressed on cancer cells for tumor-cell-specific delivery. The present review compiles the recent advances in dendrimer-mediated drug and gene delivery to tumors by passive and active targeting principles with illustrative examples. PMID:25555748

  10. Glycopeptide dendrimers. Part I

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2008-01-01

    Roč. 14, č. 1 (2008), s. 2-43 ISSN 1075-2617 R&D Projects: GA ČR GA203/03/1362; GA ČR GA203/06/1272; GA MZe QF3115; GA AV ČR KAN200520703 Institutional research plan: CEZ:AV0Z40550506 Keywords : artificial virus * calixarene dendrimers * carbopeptide dendrimers * glycopeptide dendrimers Subject RIV: CC - Organic Chemistry Impact factor: 1.654, year: 2008

  11. Ekspresi HER2/neu(c-ErbB2 pada Kanker Kolorektal

    Directory of Open Access Journals (Sweden)

    Nita Afriani

    2014-12-01

    Full Text Available Kanker kolorektal merupakan keganasan pada kolon dan rektum, penyebab morbiditas danmortalitas ketiga terbanyak diantara keganasan lainnya. Penelitian ekspresi HER2 pada kankerkolorektal memiliki rentang yang cukup jauh yaitu 0-83% dan belum pernah dipublikasi dilndonesia. Penelitian ini bertujuan untuk menilai ekspresi HER2 pada kanker kolorektal. Studicross-secfiona/ dilakukan terhadap 51 sediaan blok parafin kanker kolorektal rentang tahunJanuari 2011-Desember 2012 di Departemen Patologi Anatorni RS Cipto MangunkusumoJakarta. Penilaian karakteristik sampel diambil dari rekam medis dan penilaian histopatologidari sediaan HE pasien kanker kolorektal. Pulasan imunohistokimia HER2 menggunakanantibodipoliklonalantiHER2(DAKO. Rata-rata usia penderita adalah 57.8t13.54tahun,58.8%penderita adalah laki-laki dan 41.2o/o perempuan. Semua sediaan adalah adenokarsinomakolorektal. Ekspresi HER2 positif ditemukan sebanyak 5(9.8% kasus.AbstractColorectal cancer is a neoplasia of colon and rectum ,and also the 3rd leading cause ofmorbidity and mortality among men and women in the world. HER2 expression has controversialresults ranging from 0-83% and never been pubiished in lndonesia. This research aims tostudy HER2 expression in colorectal cancer. Cross-sectional study was conducted in 51 casesof colorectal cancer from January 2011 until December 2012 in Pathology Department ofCipto Mangunkusumo Hospital. Patient characteristic was reviewed from medical record andhistopathologic was evaluated from HE slides. lmunohistochemistry staining used anti HER2polyclonal antibody frorn DAKO. Mean age was 57.8113.54 years, 58.8% were males and41.2o4 were females. Positive HER2 was 5 cases (9.8%.

  12. Effect of Mass Transport in the Synthesis of Partially Acetylated Dendrimer: Implications for Functional Ligand–Nanoparticle Distributions

    OpenAIRE

    Mullen, Douglas G.; Borgmeier, Emilee L.; Fang, Ming; McNerny, Daniel Q.; Desai, Ankur; Baker, James R.; Orr, Bradford G.; Holl, Mark M. Banaszak

    2010-01-01

    Partial acetylation of the amine-terminated poly(amidoamine) dendrimer has been used in the preparation of dendrimer particles conjugated with a wide variety of functional ligands including targeting moieties, therapeutic agents, and dye molecules. The effectiveness of mass transport during the partial acetylation reaction was found to have a major effect on subsequent distributions of dendrimer–ligand components and to be a major source of inconsistency between batches. This study has broad ...

  13. Phosphorus dendrimers and photodynamic therapy. Spectroscopic studies on two dendrimer-photosensitizer complexes: Cationic phosphorus dendrimer with rose bengal and anionic phosphorus dendrimer with methylene blue.

    Science.gov (United States)

    Dabrzalska, Monika; Zablocka, Maria; Mignani, Serge; Majoral, Jean Pierre; Klajnert-Maculewicz, Barbara

    2015-08-15

    Dendrimers due to their unique architecture may play an important role in drug delivery systems including chemotherapy, gene therapy and recently, photodynamic therapy as well. We investigated two dendrimer-photosensitizer systems in context of potential use of these systems in photodynamic therapy. The mixtures of an anionic phosphorus dendrimer of the second generation and methylene blue were studied by UV-vis spectroscopy while that of a cationic phosphorus dendrimer (third generation) and rose bengal were investigated by spectrofluorimetric methods. Spectroscopic analysis of these two systems revealed the formation of dendrimer-photosensitizer complexes via electrostatic interactions as well as π stacking. The stoichiometry of the rose bengal-cationic dendrimer complex was estimated to be 7:1 and 9:1 for the methylene blue-anionic dendrimer complex. The results suggest that these polyanionic or polycationic phosphorus dendrimers can be promising candidates as carriers in photodynamic therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Synthesis, characterization and in vitro evaluation of exquisite targeting SPIONs–PEG–HER in HER2+ human breast cancer cells

    International Nuclear Information System (INIS)

    Almaki, Javad Hamzehalipour; Nasiri, Rozita; Idris, Ani; Majid, Fadzilah Adibah Abdul; Wong, Tet Soon; Salouti, Mojtaba; Dabagh, Shadab; Marvibaigi, Mohsen; Amini, Neda

    2016-01-01

    A stable, biocompatible and exquisite SPIONs–PEG–HER targeting complex was developed. Initially synthesized superparamagnetic iron oxide nanoparticles (SPIONs) were silanized using 3-aminopropyltrimethoxysilane (APS) as the coupling agent in order to allow the covalent bonding of polyethylene glycol (PEG) to the SPIONs to improve the biocompatibility of the SPIONs. SPIONs–PEG were then conjugated with herceptin (HER) to permit the SPIONs–PEG–HER to target the specific receptors expressed over the surface of the HER2+ metastatic breast cancer cells. Each preparation step was physico-chemically analyzed and characterized by a number of analytical methods including AAS, FTIR spectroscopy, XRD, FESEM, TEM, DLS and VSM. The biocompatibility of SPIONs–PEG–HER was evaluated in vitro on HSF-1184 (human skin fibroblast cells), SK-BR-3 (human breast cancer cells, HER+), MDA-MB-231 (human breast cancer cells, HER−) and MDA-MB-468 (human breast cancer cells, HER−) cell lines by performing MTT and trypan blue assays. The hemolysis analysis results of the SPIONs–PEG–HER and SPIONs–PEG did not indicate any sign of lysis while in contact with erythrocytes. Additionally, there were no morphological changes seen in RBCs after incubation with SPIONs–PEG–HER and SPIONs–PEG under a light microscope. The qualitative and quantitative in vitro targeting studies confirmed the high level of SPION–PEG–HER binding to SK-BR-3 (HER2+ metastatic breast cancer cells). Thus, the results reflected that the SPIONs–PEG–HER can be chosen as a favorable biomaterial for biomedical applications, chiefly magnetic hyperthermia, in the future. (paper)

  15. Dendrimers for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Abhay Singh Chauhan

    2018-04-01

    Full Text Available Dendrimers have come a long way in the last 25 years since their inception. Originally created as a wonder molecule of chemistry, dendrimer is now in the fourth class of polymers. Dr. Donald Tomalia first published his seminal work on Poly(amidoamine (PAMAM dendrimers in 1985. Application of dendrimers as a drug delivery system started in late 1990s. Dendrimers for drug delivery are employed using two approaches: (i formulation and (ii nanoconstruct. In the formulation approach, drugs are physically entrapped in a dendrimer using non-covalent interactions, whereas drugs are covalently coupled on dendrimers in the nanoconstruct approach. We have demonstrated the utility of PAMAM dendrimers for enhancing solubility, stability and oral bioavailability of various drugs. Drug entrapment and drug release from dendrimers can be controlled by modifying dendrimer surfaces and generations. PAMAM dendrimers are also shown to increase transdermal permeation and specific drug targeting. Dendrimer platforms can be engineered to attach targeting ligands and imaging molecules to create a nanodevice. Dendrimer nanotechnology, due to its multifunctional ability, has the potential to create next generation nanodevices.

  16. Atomistic computer simulations on multi-loaded PAMAM dendrimers: a comparison of amine- and hydroxyl-terminated dendrimers

    Science.gov (United States)

    Badalkhani-Khamseh, Farideh; Ebrahim-Habibi, Azadeh; Hadipour, Nasser L.

    2017-12-01

    Poly(amidoamine) (PAMAM) dendrimers have been extensively studied as delivery vectors in biomedical applications. A limited number of molecular dynamics (MD) simulation studies have investigated the effect of surface chemistry on therapeutic molecules loading, with the aim of providing insights for biocompatibility improvement and increase in drug loading capacity of PAMAM dendrimers. In this work, fully atomistic MD simulations were employed to study the association of 5-Fluorouracil (5-FU) with amine (NH2)- and hydroxyl (OH)-terminated PAMAM dendrimers of generations 3 and 4 (G3 and G4). MD results show a 1:12, 1:1, 1:27, and 1:4 stoichiometry, respectively, for G3NH2-FU, G3OH-FU, G4NH2-FU, and G4OH-FU complexes, which is in good agreement with the isothermal titration calorimetry results. The results obtained showed that NH2-terminated dendrimers assume segmented open structures with large cavities and more drug molecules can encapsulate inside the dendritic cavities of amine terminated dendrimers. However, OH-terminated have a densely packed structure and therefore, 5-FU drug molecules are more stable to locate close to the surface of the dendrimers. Intermolecular hydrogen bonding analysis showed that 5-FU drug molecules have more tendency to form hydrogen bonds with terminal monomers of OH-terminated dendrimers, while in NH2-terminated these occur both in the inner region and the surface. Furthermore, MM-PBSA analysis revealed that van der Waals and electrostatic energies are both important to stabilize the complexes. We found that drug molecules are distributed uniformly inside the amine and hydroxyl terminated dendrimers and therefore, both dendrimers are promising candidates as drug delivery systems for 5-FU drug molecules.

  17. A gene-protein assay for human epidermal growth factor receptor 2 (HER2: brightfield tricolor visualization of HER2 protein, the HER2 gene, and chromosome 17 centromere (CEN17 in formalin-fixed, paraffin-embedded breast cancer tissue sections

    Directory of Open Access Journals (Sweden)

    Nitta Hiroaki

    2012-05-01

    Full Text Available Abstract Background The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH or immunohistochemistry (IHC, respectively. Our objective was to combine the US Food and Drug Administration (FDA-approved HER2 & chromosome 17 centromere (CEN17 brightfield ISH (BISH and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section. Methods The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative] and Calu-3 [HER2 positive (amplified gene, protein positive]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5 and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays. Results HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene

  18. Advantages and disadvantages of technologies for HER2 testing in breast cancer specimens.

    Science.gov (United States)

    Furrer, Daniela; Sanschagrin, François; Jacob, Simon; Diorio, Caroline

    2015-11-01

    Human epidermal growth factor receptor 2 (HER2) plays a central role as a prognostic and predictive marker in breast cancer specimens. Reliable HER2 evaluation is central to determine the eligibility of patients with breast cancer to targeted anti-HER2 therapies such as trastuzumab and lapatinib. Presently, several methods exist for the determination of HER2 status at different levels (protein, RNA, and DNA level). In this review, we discuss the main advantages and disadvantages of the techniques developed so far for the evaluation of HER2 status in breast cancer specimens. Each technique has its own advantages and disadvantages. It is therefore not surprising that no consensus has been reached so far on which technique is the best for the determination of HER2 status. Currently, emphasis must be put on standardization of procedures, internal and external quality control assessment, and competency evaluation of already existing methods to ensure accurate, reliable, and clinically meaningful test results. Development of new robust and accurate diagnostic assays should also be encouraged. In addition, large clinical trials are warranted to identify the technique that most reliably predicts a positive response to anti-HER2 drugs. Copyright© by the American Society for Clinical Pathology.

  19. Determining true HER2 gene status in breast cancers with polysomy by using alternative chromosome 17 reference genes: implications for anti-HER2 targeted therapy.

    Science.gov (United States)

    Tse, Chun Hing; Hwang, Harry C; Goldstein, Lynn C; Kandalaft, Patricia L; Wiley, Jesse C; Kussick, Steven J; Gown, Allen M

    2011-11-01

    The ratio of human epidermal growth factor receptor 2 (HER2) to CEP17 by fluorescent in situ hybridization (FISH) with the centromeric probe CEP17 is used to determine HER2 gene status in breast cancer. Increases in CEP17 copy number have been interpreted as representing polysomy 17. However, pangenomic studies have demonstrated that polysomy 17 is rare. This study tests the hypothesis that the use of alternative chromosome 17 reference genes might more accurately assess true HER2 gene status. In all, 171 patients with breast cancer who had HER2 FISH that had increased mean CEP17 copy numbers (> 2.6) were selected for additional chromosome 17 studies that used probes for Smith-Magenis syndrome (SMS), retinoic acid receptor alpha (RARA), and tumor protein p53 (TP53) genes. A eusomic copy number exhibited in one or more of these loci was used to calculate a revised HER2-to-chromosome-17 ratio by using the eusomic gene locus as the reference. Of 132 cases classified as nonamplified on the basis of their HER2:CEP17 ratios, 58 (43.9%) were scored as amplified by using alternative chromosome 17 reference gene probes, and 13 (92.9%) of 14 cases scored as equivocal were reclassified as amplified. Among the cases with mean HER2 copy number of 4 to 6, 41 (47.7%) of 86 had their HER2 gene status upgraded from nonamplified to amplified, and four (4.7%) of 86 were upgraded from equivocal to amplified. Our results support the findings of recent pangenomic studies that true polysomy 17 is uncommon. Additional FISH studies that use probes to the SMS, RARA, and TP53 genes are an effective way to determine the true HER2 amplification status in patients with polysomy 17 and they have important potential implications for guiding HER2-targeted therapy in breast cancer.

  20. Dual blockade of HER2 in HER2-overexpressing tumor cells does not completely eliminate HER3 function.

    Science.gov (United States)

    Garrett, Joan T; Sutton, Cammie R; Kuba, María Gabriela; Cook, Rebecca S; Arteaga, Carlos L

    2013-02-01

    Dual blockade of HER2 with trastuzumab and lapatinib or with pertuzumab is a superior treatment approach compared with single-agent HER2 inhibitors. However, many HER2-overexpressing breast cancers still escape from this combinatorial approach. Inhibition of HER2 and downstream phosphoinositide 3-kinase (PI3K)/AKT causes a transcriptional and posttranslational upregulation of HER3 which, in turn, counteracts the antitumor action of the HER2-directed therapies. We hypothesized that suppression of HER3 would synergize with dual blockade of HER2 in breast cancer cells sensitive and refractory to HER2 antagonists. Inhibition of HER2/HER3 in HER2(+) breast cancer cell lines was evaluated by Western blotting. We analyzed drug-induced apoptosis and two- and three-dimensional growth in vitro. Growth inhibition of PI3K was examined in vivo in xenografts treated with combinations of trastuzumab, lapatinib, and the HER3-neutralizing monoclonal antibody U3-1287. Treatment with U3-1287 blocked the upregulation of total and phosphorylated HER3 that followed treatment with lapatinib and trastuzumab and, in turn, enhanced the antitumor action of the combination against trastuzumab-sensitive and -resistant cells. Mice bearing HER2(+) xenografts treated with lapatinib, trastuzumab, and U3-1287 exhibited fewer recurrences and better survival than mice treated with lapatinib and trastuzumab. Dual blockade of HER2 with trastuzumab and lapatinib does not eliminate the compensatory upregulation of HER3. Therapeutic inhibitors of HER3 should be considered as part of multidrug combinations aimed at completely and rapidly disabling the HER2 network in HER2-overexpressing breast cancers.

  1. RGD peptide-modified multifunctional dendrimer platform for drug encapsulation and targeted inhibition of cancer cells.

    Science.gov (United States)

    He, Xuedan; Alves, Carla S; Oliveira, Nilsa; Rodrigues, João; Zhu, Jingyi; Bányai, István; Tomás, Helena; Shi, Xiangyang

    2015-01-01

    Development of multifunctional nanoscale drug-delivery systems for targeted cancer therapy still remains a great challenge. Here, we report the synthesis of cyclic arginine-glycine-aspartic acid (RGD) peptide-conjugated generation 5 (G5) poly(amidoamine) dendrimers for anticancer drug encapsulation and targeted therapy of cancer cells overexpressing αvβ3 integrins. In this study, amine-terminated G5 dendrimers were used as a platform to be sequentially modified with fluorescein isothiocyanate (FI) via a thiourea linkage and RGD peptide via a polyethylene glycol (PEG) spacer, followed by acetylation of the remaining dendrimer terminal amines. The developed multifunctional dendrimer platform (G5.NHAc-FI-PEG-RGD) was then used to encapsulate an anticancer drug doxorubicin (DOX). We show that approximately six DOX molecules are able to be encapsulated within each dendrimer platform. The formed complexes are water-soluble, stable, and able to release DOX in a sustained manner. One- and two-dimensional NMR techniques were applied to investigate the interaction between dendrimers and DOX, and the impact of the environmental pH on the release rate of DOX from the dendrimer/DOX complexes was also explored. Furthermore, cell biological studies demonstrate that the encapsulation of DOX within the G5.NHAc-FI-PEG-RGD dendrimers does not compromise the anticancer activity of DOX and that the therapeutic efficacy of the dendrimer/DOX complexes is solely related to the encapsulated DOX drug. Importantly, thanks to the role played by RGD-mediated targeting, the developed dendrimer/drug complexes are able to specifically target αvβ3 integrin-overexpressing cancer cells and display specific therapeutic efficacy to the target cells. The developed RGD peptide-targeted multifunctional dendrimers may thus be used as a versatile platform for targeted therapy of different types of αvβ3 integrin-overexpressing cancer cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Evaluation of an anti-p185{sup HER2} (scFv-C{sub H}2-C{sub H}3){sub 2} fragment following radioiodination using two different residualizing labels: SGMIB and IB-Mal-D-GEEEK

    Energy Technology Data Exchange (ETDEWEB)

    Vaidyanathan, Ganesan [Duke University Medical Center, Durham, NC 27710 (United States)], E-mail: ganesan.v@duke.edu; Jestin, Emmanuelle [Duke University Medical Center, Durham, NC 27710 (United States); Olafsen, Tove; Wu, Anna M. [Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095 (United States); Zalutsky, Michael R. [Duke University Medical Center, Durham, NC 27710 (United States)

    2009-08-15

    Introduction: A 105-kDa double mutant single-chain Fv-Fc fragment (scFv-Fc DM) derived from the anti-p185{sup HER2} hu4D5v8 antibody (trastuzumab; Herceptin) has been described recently. The goal of this study was to investigate whether improved tumor targeting could be achieved with this fragment through the use of residualizing radioiodination methods. Methods: The scFv-Fc DM fragment was radioiodinated using N-succinimidyl 4-guanidinomethyl 3-[{sup 131}I]iodobenzoate ([{sup 131}I]SGMIB) and N{sup {epsilon}}-(3-[{sup 131}I]iodobenzoyl)-Lys{sup 5}-N{sup {alpha}}- maleimido-Gly{sup 1}-GEEEK ([{sup 131}I]IB-Mal-D-GEEEK), two residualizing radioiodination agents that have been used successfully with intact antibodies. Paired-label internalization assays of the labeled fragments were performed in vitro using MCF7 human breast cancer cells transfected to express HER2 (MCF7-HER2); comparisons were made to scFv-Fc DM directly radioiodinated using Iodogen. The tissue distribution of the scFv-Fc DM labeled with [{sup 125}I]IB-Mal-D-GEEEK and [{sup 131}I]SGMIB was compared in athymic mice bearing MCF7-HER2 xenografts. Results: The scFv-Fc DM fragment was labeled with [{sup 131}I]SGMIB and [{sup 131}I]IB-Mal-D-GEEEK in conjugation yields of 53% and 25%, respectively, with preservation of immunoreactivity for HER2. Internalization assays indicated that labeling via SGMIB resulted in a 1.6- to 3.5-fold higher (P<.05) retention of radioactivity, compared to that from the directly labeled fragment, in HER2-expressing cells during a 24-h observation period. Likewise, the amount of radioactivity retained in cells from the IB-Mal-D-GEEEK-labeled fragment was 1.4- to 3.3-fold higher (P<.05). Tumor uptake of radioiodine activity in athymic mice bearing MCF7-HER2 xenografts in vivo was significantly higher for the [{sup 125}I]IB-Mal-D-GEEEK-labeled scFv-Fc DM fragment compared with that of the [{sup 131}I]SGMIB-labeled fragment, particularly at later time points. The uptake of {sup

  3. Targeted Delivery of Deoxycytidine Kinase to Her2-Positive Cells Enhances the Efficacy of the Nucleoside Analog Fludarabine.

    Directory of Open Access Journals (Sweden)

    Sujatha P Koduvayur

    Full Text Available Cytotoxic drugs, such as nucleoside analogs and toxins, commonly suffer from off-target effects. One approach to mitigate this problem is to deliver the cytotoxic drug selectively to the intended site. While for toxins this can be achieved by conjugating the cell-killing moiety to a targeting moiety, it is not an option for nucleoside analogs, which rely on intracellular enzymes to convert them to their active triphosphorylated form. To overcome this limitation, and achieve site-targeted activation of nucleoside analogs, we fused the coding region of a prodrug-activating enzyme, deoxycytidine kinase (dCK, to affinity reagents that bind to the Her2 cell surface protein. We evaluated dCK fusions to an anti-Her2 affibody and Designed Ankyrin Repeat Protein (DARPin for their ability to kill cancer cells by promoting the activation of the nucleoside analog fludarabine. Cell staining and flow cytometry experiments with three Her2 positive cancer cell lines (BT-474-JB, JIMT-1 and SK-OV-3 indicate dCK fusions binding and cellular internalization. In contrast, these reagents bind only weakly to the Her2 negative cell line, MCF-7. Cell proliferation assays indicate that SK-OV-3 and BT-474-JB cell lines exhibit significantly reduced proliferation rates when treated with targeting-module fused dCK and fludarabine, compared to fludarabine alone. These findings demonstrate that we have succeeded in delivering active dCK into the Her2-positive cells, thereby increasing the activation of fludarabine, which ultimately reduces the dose of nucleoside analog needed for cell killing. This strategy may help establish the therapeutic index required to differentiate between healthy tissues and cancer cells.

  4. Fluorescence Quenching of Dendrimer-Encapsulated CdS Quantum Dots for the Detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyojung; Kim, Hai Dong; Kim, Joohoon [Kyung Hee Un iversity, Seoul (Korea, Republic of)

    2016-02-15

    Hydrogen peroxide (H{sub 2}O{sub 2}) exists in natural environments as a byproduct of various enzymatic and photochemical reactions. Various approaches have been reported for the synthesis of cadmium sulfide (CdS) QDs using dendrimers, which can be categorized mainly into two general approaches. The first approach utilizes dendrimers as capping agents, resulting in the formation of agglomerates of spatially segregated QDs stabilized by multiple dendrimers. We have described the synthesis and characterization of the CdS QDs using G6-NH{sub 2} dendrimers. By controlling the molar ratios (n = Cd2+/G6-NH{sub 2}) between the Cd{sup 2+} ions and G6-NH{sub 2} dendrimers, we synthesized a set of CdS QDs with different structural and optical properties. Importantly, the synthesized CdS QDs exhibited H{sub 2}O{sub 2}-sensitive fluorescence, which can be utilized for the detection of H{sub 2}O{sub 2}. Especially, the CdS QDs with n = 64 displayed a Stern–Volmer relationship between the fluorescence of the CdS QDs and the concentration of H{sub 2}O{sub 2}, as well as the strongest fluorescence among the set of the synthesized CdS QDs. Since core-shell structures of QDs often result in enhanced stability and quantum efficiency of the QDs, we are currently working on core-shell structured QDs prepared using dendrimers to improve their stability and quantum yield compared to the CdS QDs reported in the present study.

  5. Activating HER2 mutations in HER2 gene amplification negative breast cancer.

    Science.gov (United States)

    Bose, Ron; Kavuri, Shyam M; Searleman, Adam C; Shen, Wei; Shen, Dong; Koboldt, Daniel C; Monsey, John; Goel, Nicholas; Aronson, Adam B; Li, Shunqiang; Ma, Cynthia X; Ding, Li; Mardis, Elaine R; Ellis, Matthew J

    2013-02-01

    Data from 8 breast cancer genome-sequencing projects identified 25 patients with HER2 somatic mutations in cancers lacking HER2 gene amplification. To determine the phenotype of these mutations, we functionally characterized 13 HER2 mutations using in vitro kinase assays, protein structure analysis, cell culture, and xenograft experiments. Seven of these mutations are activating mutations, including G309A, D769H, D769Y, V777L, P780ins, V842I, and R896C. HER2 in-frame deletion 755-759, which is homologous to EGF receptor (EGFR) exon 19 in-frame deletions, had a neomorphic phenotype with increased phosphorylation of EGFR or HER3. L755S produced lapatinib resistance, but was not an activating mutation in our experimental systems. All of these mutations were sensitive to the irreversible kinase inhibitor, neratinib. These findings show that HER2 somatic mutation is an alternative mechanism to activate HER2 in breast cancer and they validate HER2 somatic mutations as drug targets for breast cancer treatment. We show that the majority of HER2 somatic mutations in breast cancer patients are activating mutations that likely drive tumorigenesis. Several patients had mutations that are resistant to the reversible HER2 inhibitor lapatinib, but are sensitive to the irreversible HER2 inhibitor, neratinib. Our results suggest that patients with HER2 mutation–positive breast cancers could benefit from existing HER2-targeted drugs.

  6. Cell uptake mechanisms of PAMAM G4-FITC dendrimer in human myometrial cells

    International Nuclear Information System (INIS)

    Oddone, Natalia; Zambrana, Ana I.; Tassano, Marcos; Porcal, Williams; Cabral, Pablo; Benech, Juan C.

    2013-01-01

    The high incidence and severity of diseases which involve smooth muscle dysfunction dictates the need of continued search for novel therapeutic strategies to treat these conditions. Dendrimers are branched macromolecules with multiple end-groups that can be functionalized for applications which include drug delivery. There is no data regarding the cellular uptake mechanisms used by dendrimers in smooth muscle human myometrial cells (HMC). Polyamidoamine G4 dendrimers were conjugated with fluorescein isothiocyanate (FITC) and the resulting conjugate (G4-FITC) was characterized using high-performance liquid chromatography, nuclear magnetic resonance, and atomic force microscopy. G4-FITC showed to have no significant effect on the primary culture HMC viability up to 48 h. HMC incubated with G4-FITC were analyzed by laser confocal microscopy. Peri-nuclear fluorescence distribution was observed at 5 h of incubation or more (24, 36, and 48 h). At 24 h, G4-FITC partially co-localized with lysotracker. Uptake of G4-FITC by HMC was slightly inhibited by filipin (8.0 ± 3.9 %) and significantly inhibited by chlorpromazine (63.5 ± 3.7 %). In non-electroporated HMC, G4-FITC was never observed inside the cell nucleus. Interestingly, we detected G4-FITC inside the nuclear domain of some electroporated cells. Thus, electroporation changed intracellular G4-FITC localization. Isolated nuclei of HMC incubated with G4-FITC showed fluorescence signal inside the nuclear domain. The results suggest that in HMC, G4-FITC is taken up by clathrin-mediated endocytosis with endosomal and lysosomal localization at 24 h. The combination of electroporation and dendrimers could be an interesting technology to electrotransfer drugs into smooth muscle cells cytosol and nuclei

  7. Cell uptake mechanisms of PAMAM G4-FITC dendrimer in human myometrial cells

    Energy Technology Data Exchange (ETDEWEB)

    Oddone, Natalia; Zambrana, Ana I.; Tassano, Marcos [Instituto de Investigaciones Biologicas Clemente Estable, Laboratorio de Senalizacion Celular y Nanobiologia (Uruguay); Porcal, Williams [Universidad de la Republica, Grupo de Quimica Medicinal, Instituto de Quimica Biologica, Facultad de Ciencias-Facultad de Quimica (Uruguay); Cabral, Pablo [Universidad de la Republica, Laboratorio de Radiofarmacia, Centro de Investigaciones Nucleares, Facultad de Ciencias (Uruguay); Benech, Juan C., E-mail: benech@iibce.edu.uy [Instituto de Investigaciones Biologicas Clemente Estable, Laboratorio de Senalizacion Celular y Nanobiologia (Uruguay)

    2013-07-15

    The high incidence and severity of diseases which involve smooth muscle dysfunction dictates the need of continued search for novel therapeutic strategies to treat these conditions. Dendrimers are branched macromolecules with multiple end-groups that can be functionalized for applications which include drug delivery. There is no data regarding the cellular uptake mechanisms used by dendrimers in smooth muscle human myometrial cells (HMC). Polyamidoamine G4 dendrimers were conjugated with fluorescein isothiocyanate (FITC) and the resulting conjugate (G4-FITC) was characterized using high-performance liquid chromatography, nuclear magnetic resonance, and atomic force microscopy. G4-FITC showed to have no significant effect on the primary culture HMC viability up to 48 h. HMC incubated with G4-FITC were analyzed by laser confocal microscopy. Peri-nuclear fluorescence distribution was observed at 5 h of incubation or more (24, 36, and 48 h). At 24 h, G4-FITC partially co-localized with lysotracker. Uptake of G4-FITC by HMC was slightly inhibited by filipin (8.0 {+-} 3.9 %) and significantly inhibited by chlorpromazine (63.5 {+-} 3.7 %). In non-electroporated HMC, G4-FITC was never observed inside the cell nucleus. Interestingly, we detected G4-FITC inside the nuclear domain of some electroporated cells. Thus, electroporation changed intracellular G4-FITC localization. Isolated nuclei of HMC incubated with G4-FITC showed fluorescence signal inside the nuclear domain. The results suggest that in HMC, G4-FITC is taken up by clathrin-mediated endocytosis with endosomal and lysosomal localization at 24 h. The combination of electroporation and dendrimers could be an interesting technology to electrotransfer drugs into smooth muscle cells cytosol and nuclei.

  8. NSCLC and HER2: between lights and shadows.

    Science.gov (United States)

    Ricciardi, Giuseppina Rosaria Rita; Russo, Alessandro; Franchina, Tindara; Ferraro, Giuseppa; Zanghì, Mariangela; Picone, Antonio; Scimone, Antonino; Adamo, Vincenzo

    2014-12-01

    The therapeutic landscape of non-small-cell lung cancer (NSCLC) has dramatically changed in the last few years with the introduction of molecularly targeted agents, leading to unprecedented results in lung tumors with a paradigmatic shift from a "one size fits all" approach to an histologic and molecular-based approach. The discovery of epidermal growth factor receptor (EGFR) mutations in NSCLC in 2004 and the marked response to the EGFR tyrosine kinase inhibitor gefitinib, in a small subset of patients harboring these genetic abnormalities, stimulated the study of other kinase mutants involvement in NSCLC. The incredible story of ALK rearranged tumors, with the rapid Food and Drug Administration approval of Crizotinib after only 4 years from the discovery of EML4-ALK translocation in NSCLC, has profoundly influenced the concept of drug development in NSCLC, paving the way to a novel series of molecularly selected studies with specific inhibitors. The identification of these oncogenic drivers has dramatically changed the genetic landscape of NSCLC moving away from the old concept of a large indistinct histological entity to a combination of rare clinically relevant molecular subsets. Recently, a renewed interest has been emerging on the human epidermal growth factor-2 (HER2) pathway. Genetic aberrations of this signaling pathway have been reported over time to be associated in NSCLC with different sensitivity to the EGFR tyrosine kinase inhibitors, to have a possible prognostic role and more recently HER2 amplification has been emerged as a possible mechanism in EGFR-mutated tumors of acquired resistance to the EGFR tyrosine kinase inhibitors. In addition, dysregulation of the HER2 pathway, in particular HER2 mutations (mostly, in-frame exon 20 insertions), may represent a possible novel therapeutic target in NSCLC, paving the way for a new generation of targeted agents in NSCLC. Since anecdotal case reports of clinical activity of anti-HER2 agents in NSCLC

  9. Development of paclitaxel-loaded liposomal systems with anti-her2 ...

    African Journals Online (AJOL)

    Methods: Seven different liposomal systems containing PTX, or MabHer2 or a combination of .... particle distribution via the polydispersity index ... at a constant voltage of 150 V for about 3h. ... using nano-drop spectrophotometer (BioSpec-.

  10. Emerging treatments for HER2-positive early-stage breast cancer: focus on neratinib

    Directory of Open Access Journals (Sweden)

    Kourie HR

    2017-07-01

    Full Text Available Hampig Raphael Kourie,1 Elie El Rassy,1 Florian Clatot,2,3 Evandro de Azambuja,4 Matteo Lambertini3,4 1Department of Oncology, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon; 2Department of Medical Oncology and IRON/U1245, Centre Henri Becquerel, Rouen, France; 3Breast Cancer Translational Research Laboratory, 4Department of Medicine, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium Abstract: Over the last decades, a better understanding of breast cancer heterogeneity provided tools for a biologically based personalization of anticancer treatments. In particular, the overexpression of the human epidermal growth factor receptor 2 (HER2 by tumor cells provided a specific target in these HER2-positive tumors. The development of the monoclonal antibody trastuzumab, and its approval in 1998 for the treatment of patients with metastatic disease, radically changed the natural history of this aggressive subtype of breast cancer. These findings provided strong support for the continuous research in targeting the HER2 pathway and implementing the development of new anti-HER2 targeted agents. Besides trastuzumab, a series of other anti-HER2 agents have been developed and are currently being explored for the treatment of breast cancer patients, including those diagnosed with early-stage disease. Among these agents, neratinib, an oral tyrosine kinase inhibitor that irreversibly inhibits HER1, HER2, and HER4 at the intracellular level, has shown promising results, including when administered to patients previously exposed to trastuzumab-based treatment. This article aims to review the available data on the role of the HER2 pathway in breast cancer and on the different targeted agents that have been studied or are currently under development for the treatment of patients with early-stage HER2-positive disease with a particular focus on neratinib. Keywords: breast cancer, HER2-positive, neratinib, early-stage, targeted

  11. para-Sulfonatocalix[4]arene and polyamidoamine dendrimer nanocomplexes as delivery vehicles for a novel platinum anticancer agent.

    Science.gov (United States)

    Pang, Chi Ting; Ammit, Alaina J; Ong, Yu Qing Elysia; Wheate, Nial J

    2017-11-01

    Novel para-sulfonatocalix[4]arene (sCX[4]) and polyamidoamine (PAMAM) dendrimer nanocomplexes were evaluated as delivery vehicles for the platinum anticancer agent [(1,10-phenanthroline)(1S,2S-diaminocyclohexane)platinum(II)] chloride (PHENSS). Different ratios of sCX[4] to PHENSS were tested for their compatibility, with a ratio of 6:1 sCX[4]:PHENSS having the best solubility. The loading of sCX[4], and sCX[4]-bound PHENSS, onto three different generations of PAMAM dendrimers (G3.0-5.0) was examined using UV-visible spectrophotometry. The quantity of sCX[4] bound was found to increase exponentially with dendrimer size: G3, 15 sCX[4] molecules per dendrimer; G4, 37; and G5, 78. Similarly, the loading of sCX[4]-bound PHENSS also increased with increasing dendrimer size: G3, 7 PHENSS molecules per dendrimer; G4, 14; and G5, 28.5. The loading of sCX[4]-bound PHENSS molecules is significantly lower when compared with that of sCX[4], which indicates that less than half of the binding sites were occupied (45, 44, and 44%, respectively). By 1 H NMR and UV-vis analysis, the nanocomplex was found to be stable in NaCl solutions at concentrations up to 150mM. While PHENSS is more active in vitro than cisplatin against the human breast cancer cell line, MCF-7, delivery of PHENSS using the sCX[4]-dendrimer nanocomplexes, regardless of dendrimer generation, had little effect on PHENSS cytotoxicity. The results of this study may have application in the delivery of a variety of small molecule metal-based drugs for which chemical conjugation to a nanoparticle is undesired or not feasible. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Dendrimer brain uptake and targeted therapy for brain injury in a large animal model of hypothermic circulatory arrest.

    Science.gov (United States)

    Mishra, Manoj K; Beaty, Claude A; Lesniak, Wojciech G; Kambhampati, Siva P; Zhang, Fan; Wilson, Mary A; Blue, Mary E; Troncoso, Juan C; Kannan, Sujatha; Johnston, Michael V; Baumgartner, William A; Kannan, Rangaramanujam M

    2014-03-25

    Treatment of brain injury following circulatory arrest is a challenging health issue with no viable therapeutic options. Based on studies in a clinically relevant large animal (canine) model of hypothermic circulatory arrest (HCA)-induced brain injury, neuroinflammation and excitotoxicity have been identified as key players in mediating the brain injury after HCA. Therapy with large doses of valproic acid (VPA) showed some neuroprotection but was associated with adverse side effects. For the first time in a large animal model, we explored whether systemically administered polyamidoamine (PAMAM) dendrimers could be effective in reaching target cells in the brain and deliver therapeutics. We showed that, upon systemic administration, hydroxyl-terminated PAMAM dendrimers are taken up in the brain of injured animals and selectively localize in the injured neurons and microglia in the brain. The biodistribution in other major organs was similar to that seen in small animal models. We studied systemic dendrimer-drug combination therapy with two clinically approved drugs, N-acetyl cysteine (NAC) (attenuating neuroinflammation) and valproic acid (attenuating excitotoxicity), building on positive outcomes in a rabbit model of perinatal brain injury. We prepared and characterized dendrimer-NAC (D-NAC) and dendrimer-VPA (D-VPA) conjugates in multigram quantities. A glutathione-sensitive linker to enable for fast intracellular release. In preliminary efficacy studies, combination therapy with D-NAC and D-VPA showed promise in this large animal model, producing 24 h neurological deficit score improvements comparable to high dose combination therapy with VPA and NAC, or free VPA, but at one-tenth the dose, while significantly reducing the adverse side effects. Since adverse side effects of drugs are exaggerated in HCA, the reduced side effects with dendrimer conjugates and suggestions of neuroprotection offer promise for these nanoscale drug delivery systems.

  13. Neratinib overcomes trastuzumab resistance in HER2 amplified breast cancer.

    Science.gov (United States)

    Canonici, Alexandra; Gijsen, Merel; Mullooly, Maeve; Bennett, Ruth; Bouguern, Noujoude; Pedersen, Kasper; O'Brien, Neil A; Roxanis, Ioannis; Li, Ji-Liang; Bridge, Esther; Finn, Richard; Siamon, Dennis; McGowan, Patricia; Duffy, Michael J; O'Donovan, Norma; Crown, John; Kong, Anthony

    2013-10-01

    Trastuzumab has been shown to improve the survival outcomes of HER2 positive breast cancer patients. However, a significant proportion of HER2-positive patients are either inherently resistant or develop resistance to trastuzumab. We assessed the effects of neratinib, an irreversible panHER inhibitor, in a panel of 36 breast cancer cell lines. We further assessed its effects with or without trastuzumab in several sensitive and resistant breast cancer cells as well as a BT474 xenograft model. We confirmed that neratinib was significantly more active in HER2-amplified than HER2 non-amplified cell lines. Neratinib decreased the activation of the 4 HER receptors and inhibited downstream pathways. However, HER3 and Akt were reactivated at 24 hours, which was prevented by the combination of trastuzumab and neratinib. Neratinib also decreased pHER2 and pHER3 in acquired trastuzumab resistant cells. Neratinib in combination with trastuzumab had a greater growth inhibitory effect than either drug alone in 4 HER2 positive cell lines. Furthermore, trastuzumab in combination with neratinib was growth inhibitory in SKBR3 and BT474 cells which had acquired resistance to trastuzumab as well as in a BT474 xenograft model. Innately trastuzumab resistant cell lines showed sensitivity to neratinib, but the combination did not enhance response compared to neratinib alone. Levels of HER2 and phospho-HER2 showed a direct correlation with sensitivity to neratinib. Our data indicate that neratinib is an effective anti-HER2 therapy and counteracted both innate and acquired trastuzumab resistance in HER2 positive breast cancer. Our results suggest that combined treatment with trastuzumab and neratinib is likely to be more effective than either treatment alone for both trastuzumab-sensitive breast cancer as well as HER2-positive tumors with acquired resistance to trastuzumab.

  14. The ABP Dendrimer, a Drug-Candidate against Inflammatory Diseases That Triggers the Activation of Interleukin-10 Producing Immune Cells.

    Science.gov (United States)

    Fruchon, Séverine; Poupot, Rémy

    2018-05-25

    The ABP dendrimer, which is built on a phosphorus-based scaffold and bears twelve azabisphosphonate groups at its surface, is one of the dendrimers that has been shown to display immuno-modulatory and anti-inflammatory effects towards the human immune system. Its anti-inflammatory properties have been successfully challenged in animal models of inflammatory disorders. In this review, we trace the discovery and the evaluation of the therapeutic effects of the ABP dendrimer in three different animal models of both acute and chronic inflammatory diseases. We emphasize that its therapeutic effects rely on the enhancement of the production of Interleukin-10, the paradigm of anti-inflammatory cytokines, by different subsets of immune cells, such as monocytes/macrophages and CD4+ T lymphocytes.

  15. The updated network meta-analysis of neoadjuvant therapy for HER2-positive breast cancer.

    Science.gov (United States)

    Nakashoji, Ayako; Hayashida, Tetsu; Yokoe, Takamichi; Maeda, Hinako; Toyota, Tomoka; Kikuchi, Masayuki; Watanuki, Rurina; Nagayama, Aiko; Seki, Tomoko; Takahashi, Maiko; Abe, Takayuki; Kitagawa, Yuko

    2018-01-01

    We previously described a systematic assessment of the neoadjuvant therapies for human epidermal growth factor receptor-2 (HER2) positive breast cancer, using network meta-analysis. Accumulation of new clinical data has compelled us to update the analysis. Randomized trials comparing different anti-HER2 regimens in the neoadjuvant setting were included, and odds ratio for pathologic complete response (pCR) in seven treatment arms were assessed by pooling effect sizes. Direct and indirect comparisons using a Bayesian statistical model were performed. All statistical tests were two-sided. A database search identified 993 articles with 13 studies meeting the eligibility criteria, including three new studies with lapatinib (lpnb). In an indirect comparison, dual anti-HER2 agents with CT achieved a better pCR rate than other arms. The credibility intervals of CT + tzmb + lpnb arm were largely reduced compared to our former report, which we added sufficient clinical evidence by this update. Values of surface under the cumulative ranking (SUCRA) suggested that CT + tzmb + pzmb had the highest probability of being the best treatment arm for pCR, widening the difference between the top two dual-HER2 blockade arms compared to our former report. The overall consistency with our first report enhanced the credibility of the results. Network meta-analysis using new clinical data firmly establish that combining two anti-HER2 agents with CT is most effective against HER2-positive breast cancer in the neoadjuvant setting. New pzmb related trials are required to fully determine the best neoadjuvant dual-HER2 blockade regimen. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Study of the interactions of PAMAM-NH2 G4 dendrimer with selected natural amino acids in aqueous solutions

    International Nuclear Information System (INIS)

    Buczkowski, Adam; Palecz, Bartlomiej

    2014-01-01

    Highlights: • Calorimetric titration and dilution calorimetry show strong interactions between PAMAM-NH 2 G4 dendrimer and amino acids. • The more polar the amino acid side chain, the more exothermic the effects of the direct interactions with dendrimer. • Macromolecule of PAMAM-NH 2 G4 dendrimer can coordinate 20 to 40 molecules of amino acid. -- Abstract: The interactions of PAMAM-NH 2 G4 dendrimer with selected natural amino acids (Gly, Ala, Val, Leu, Ile, Phe, Ser, Thr, Met, Asn, Gln, Pro and Trp) in aqueous solutions were measured with the use of the techniques of calorimetric titration and dilution calorimetry. The results of calorimetric measurements show strong interactions between PAMAM-NH 2 G4 dendrimer and amino acids with polar substituents. A macromolecule of PAMAM-NH 2 G4 dendrimer can coordinate 20 to 40 molecules of amino acid

  17. Engineering CNDP's of dendrimers containing phosphorous interior compositions to produce new emerging properties

    Science.gov (United States)

    Caminade, Anne-Marie; Majoral, Jean-Pierre

    2018-03-01

    Phosphorus-containing dendrimers are defined as dendrimers having at least one phosphorus atom at each branching point. In this review, we will show how phosphorhydrazone dendrimers can be modified at will at the level of the core and of the branches, to afford specific properties, such as fluorescence to image biological events. Accelerated methods of synthesis of phosphorus (one step for one generation) will be also displayed, as well as the specific reactivity of P=N-P=S linkages obtained in most of these accelerated method of synthesis, which has led to particularly original dendritic architectures, such as dendrons included in dendrimers. Finally, we will display how modifications of the internal structure of a series of dendrimers having the same type and number of terminal functions can deeply modify their biological anti-inflammatory properties. Among the six critical nanoscale design parameters (CNDP), we will show how two of them, i.e., architecture and elemental composition, have been particularly engineered to modify phosphorus-containing dendrimers, in order to fulfill the desired properties.

  18. ANTI-INFLAMMATORY EFFECT OF ANTI-TNF-ALPHA siRNA CATIONIC PHOSPHOROUS DENDRIMERS NANOCOMPLEXES ADMINISTERED INTRANASALLY IN A MURINE ACUTE LUNG INJURY MODEL

    DEFF Research Database (Denmark)

    Bohr, Adam; Tsapis, Nicolas; Andreana, Ilaria

    2017-01-01

    lung injury model. To achieve this goal, two different types of phosphorus-based dendrimers with either pyrrolidinium or morpholinium as terminal protonated amino groups were selected for their better biocompatibility compared to other dendrimers. Dendriplexes containing pyrrolidinium surface groups...

  19. A VAR2CSA:CSP conjugate capable of inducing dual specificity antibody responses

    DEFF Research Database (Denmark)

    Matondo, Sungwa; Thrane, Susan; Janitzek, Christoph Mikkel

    2017-01-01

    Catcher peptide. The covalent interaction between SpyTag/SpyCatcher enables the formation of DBL1x-DBL2x-ID2a:CSP conjugate vaccine. Immunogenicity and quality of antibody responses induced by the conjugate vaccine, as well as a control CSP-SpyCatcher vaccine, was tested in BALB/c mice.  Results: Serum samples...... obtained from mice immunized with the conjugate vaccine were able to recognize both untagged DBL1x-DBL2x-ID2a as well as CSP antigen. Moreover, the geometric mean anti-CSP antibody titer was 1.9-fold higher in serum (at day 35 and 55 post-first immunization) from mice immunized with the conjugate vaccine......, as compared to mice receiving the control vaccine.  Conclusion: The data obtained in this study serves as proof-of-concept for the simultaneous induction of antibodies directed against individual antigen components in a dual stage anti-malaria vaccine....

  20. Transepithelial and endothelial transport of poly (amidoamine) dendrimers.

    Science.gov (United States)

    Kitchens, Kelly M; El-Sayed, Mohamed E H; Ghandehari, Hamidreza

    2005-12-14

    This article summarizes our efforts to evaluate the potential of poly (amidoamine) (PAMAM) dendrimers as carriers for oral drug delivery. Specifically, the permeability of a series of cationic PAMAM-NH2 (G0-G4) dendrimers across Caco-2 cell monolayers was evaluated as a function of dendrimer generation, concentration, and incubation time. The influence of dendrimer surface charge on the integrity, paracellular permeability, and viability of Caco-2 cell monolayers was monitored by measuring the transepithelial electrical resistance (TEER), 14C-mannitol permeability, and leakage of lactate dehydrogenase (LDH) enzyme, respectively. Microvascular extravasation of PAMAM-NH2 dendrimers in relation to their size, molecular weight, and molecular geometry is also discussed. Results of these studies show that transepithelial transport and microvascular extravasation of PAMAM dendrimers are dependent on their structural features including molecular size, molecular geometry, and surface chemistry. These results suggest that by optimizing the size and surface charge of PAMAM dendrimers, it is possible to develop oral delivery systems based on these carriers for targeted drug delivery.

  1. Leptin/HER2 crosstalk in breast cancer: in vitro study and preliminary in vivo analysis

    International Nuclear Information System (INIS)

    Fiorio, Elena; Bonetti, Franco; Giordano, Antonio; Cetto, Gian Luigi; Surmacz, Eva; Mercanti, Anna; Terrasi, Marianna; Micciolo, Rocco; Remo, Andrea; Auriemma, Alessandra; Molino, Annamaria; Parolin, Veronica; Di Stefano, Bruno

    2008-01-01

    Obesity in postmenopausal women is associated with increased breast cancer risk, development of more aggressive tumors and resistance to certain anti-breast cancer treatments. Some of these effects might be mediated by obesity hormone leptin, acting independently or modulating other signaling pathways. Here we focused on the link between leptin and HER2. We tested if HER2 and the leptin receptor (ObR) can be coexpressed in breast cancer cell models, whether these two receptors can physically interact, and whether leptin can transactivate HER2. Next, we studied if leptin/ObR can coexist with HER2 in breast cancer tissues, and if presence of these two systems correlates with specific clinicopathological features. Expression of ObR, HER2, phospo-HER2 was assessed by immonoblotting. Physical interactions between ObR and HER2 were probed by immunoprecipitation and fluorescent immunostaining. Expression of leptin and ObR in breast cancer tissues was detected by immunohistochemistry (IHC). Associations among markers studied by IHC were evaluated using Fisher's exact test for count data. HER2 and ObR were coexpressed in all studied breast cancer cell lines. In MCF-7 cells, HER2 physically interacted with ObR and leptin treatment increased HER2 phosphorylation on Tyr 1248. In 59 breast cancers, the presence of leptin was correlated with ObR (the overall association was about 93%). This result was confirmed both in HER2-positive and in HER2-negative subgroups. The expression of leptin or ObR was numerically more frequent in larger (> 10 mm) tumors. Coexpression of HER2 and the leptin/ObR system might contribute to enhanced HER2 activity and reduced sensitivity to anti-HER2 treatments

  2. Efficacy of HIV antiviral polyanionic carbosilane dendrimer G2-S16 in the presence of semen

    Directory of Open Access Journals (Sweden)

    Ceña-Diez R

    2016-05-01

    Full Text Available Rafael Ceña-Diez,1–4,* Pilar García-Broncano,1–5,* Francisco Javier de la Mata,4,6 Rafael Gómez,4,6 Mª Ángeles Muñoz-Fernández1–4 1Hospital General Universitario Gregorio Marañon, 2Instituto de Investigación Sanitaria Gregorio Marañon, 3Spanish HIV HGM Biobank, 4Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN, 5Laboratory of Viral Infection and Immunity, National Center of Microbiology, Health Institute of Carlos III, Majadahonda, 6Department of Organic Chemistry and Inorganic Chemistry, University of Alcalá, Alcalá de Henares, Madrid, Spain *These authors contributed equally to this work Abstract: The development of a safe and effective microbicide to prevent the sexual transmission of human immunodeficiency virus (HIV-1 is urgently needed. Unfortunately, the majority of microbicides, such as poly(L-lysine-dendrimers, anionic polymers, or antiretrovirals, have proved inactive or even increased the risk of HIV infection in clinical trials, most probably due to the fact that these compounds failed to prevent semen-exposed HIV infection. We showed that G2-S16 dendrimer exerts anti-HIV-1 activity at an early stage of viral replication, blocking the gp120/CD4/CCR5 interaction and providing a barrier to infection for long periods, confirming its multifactorial and nonspecific ability. Previously, we demonstrated that topical administration of G2-S16 prevents HIV transmission in humanized BLT mice without irritation or vaginal lesions. Here, we demonstrated that G2-S16 is active against mock- and semen-exposed HIV-1 and could be a promising microbicide against HIV infection. Keywords: G2-S16, dendrimer, HIV-1, SEVI, microbicide, antiretrovirals

  3. Atomic Force Microscopy Probing of Receptor–Nanoparticle Interactions for Riboflavin Receptor Targeted Gold–Dendrimer Nanocomposites

    Science.gov (United States)

    2015-01-01

    Riboflavin receptors are overexpressed in malignant cells from certain human breast and prostate cancers, and they constitute a group of potential surface markers important for cancer targeted delivery of therapeutic agents and imaging molecules. Here we report on the fabrication and atomic force microscopy (AFM) characterization of a core–shell nanocomposite consisting of a gold nanoparticle (AuNP) coated with riboflavin receptor-targeting poly(amido amine) dendrimer. We designed this nanocomposite for potential applications such as a cancer targeted imaging material based on its surface plasmon resonance properties conferred by AuNP. We employed AFM as a technique for probing the binding interaction between the nanocomposite and riboflavin binding protein (RfBP) in solution. AFM enabled precise measurement of the AuNP height distribution before (13.5 nm) and after chemisorption of riboflavin-conjugated dendrimer (AuNP–dendrimer; 20.5 nm). Binding of RfBP to the AuNP–dendrimer caused a height increase to 26.7 nm, which decreased to 22.8 nm when coincubated with riboflavin as a competitive ligand, supporting interaction of AuNP–dendrimer and its target protein. In summary, physical determination of size distribution by AFM imaging can serve as a quantitative approach to monitor and characterize the nanoscale interaction between a dendrimer-covered AuNP and target protein molecules in vitro. PMID:24571134

  4. Comparison of the internalization of targeted dendrimers and dendrimer-entrapped gold nanoparticles into cancer cells.

    Science.gov (United States)

    Shi, Xiangyang; Wang, Su He; Lee, Inhan; Shen, Mingwu; Baker, James R

    2009-11-01

    Dendrimer-based nanotechnology significantly advances the area of targeted cancer imaging and therapy. Herein, we compared the difference of surface acetylated fluorescein isocyanate (FI) and folic acid (FA) modified generation 5 (G5) poly(amidoamine) dendrimers (G5.NHAc-FI-FA), and dendrimer-entrapped gold nanoparticles with similar modifications ([(Au(0))(51.2)-G5.NHAc-FI-FA]) in terms of their specific internalization to FA receptor (FAR)-overexpressing cancer cells. Confocal microscopic studies show that both G5.NHAc-FI-FA and [(Au(0))(51.2-)G5.NHAc-FI-FA] exhibit similar internalization kinetics regardless of the existence of Au nanoparticles (NPs). Molecular dynamics simulation of the two different nanostructures reveals that the surface area and the FA moiety distribution from the center of the geometry are slightly different. This slight difference may not be recognized by the FARs on the cell membrane, consequently leading to similar internalization kinetics. This study underlines the fact that metal or inorganic NPs entrapped within dendrimers interact with cells in a similar way to that of dendrimers lacking host NPs. 2009 Wiley Periodicals, Inc.

  5. Transferrin-bearing polypropylenimine dendrimer for targeted gene delivery to the brain.

    Science.gov (United States)

    Somani, Sukrut; Blatchford, David R; Millington, Owain; Stevenson, M Lynn; Dufès, Christine

    2014-08-28

    The possibility of using genes as medicines to treat brain diseases is currently limited by the lack of safe and efficacious delivery systems able to cross the blood-brain barrier, thus resulting in a failure to reach the brain after intravenous administration. On the basis that iron can effectively reach the brain by using transferrin receptors for crossing the blood-brain barrier, we propose to investigate if a transferrin-bearing generation 3-polypropylenimine dendrimer would allow the transport of plasmid DNA to the brain after intravenous administration. In vitro, the conjugation of transferrin to the polypropylenimine dendrimer increased the DNA uptake by bEnd.3 murine brain endothelioma cells overexpressing transferrin receptors, by about 1.4-fold and 2.3-fold compared to that observed with the non-targeted dendriplex and naked DNA. This DNA uptake appeared to be optimal following 2h incubation with the treatment. In vivo, the intravenous injection of transferrin-bearing dendriplex more than doubled the gene expression in the brain compared to the unmodified dendriplex, while decreasing the non-specific gene expression in the lung. Gene expression was at least 3-fold higher in the brain than in any tested peripheral organs and was at its highest 24h following the injection of the treatments. These results suggest that transferrin-bearing polypropylenimine dendrimer is a highly promising gene delivery system to the brain. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. HER-2-positive metastatic breast cancer: new possibilities for therapy

    Directory of Open Access Journals (Sweden)

    E. V. Artamonova

    2013-01-01

    Full Text Available This article is devoted to modern approaches in HER-2-positive metastatic breast cancer therapy. Recently treatment algorithm for this type of cancer included trastuzumab plus cytostatic in first line, continuation of trastuzumab with another chemotherapy regimen in second line, further switch to lapatinib and eventual return to trastuzumab after progression. Nowadays our options are broader owing to new anti-HER-2 agents which are pertruzumab and T-DM1. Now the most effective therapy regimen in first line is double HER-2 blockade (trastuzumab + pertuzumab in combination with docetaxel. Benefit of new agent T-DM1 versus combination of lapatinib and capecitabin is proved in patients progressed on trastuzumab and taxanes. T-DM1 also showed high efficacy as salvage therapy in intensively pretreated patients with meta- static HER-2-positive breast cancer who progressed on taxanes, trastuzumab and lapatinib.

  7. Dendrimers and Dendrons as Versatile Building Blocks for the Fabrication of Functional Hydrogels

    Directory of Open Access Journals (Sweden)

    Sadik Kaga

    2016-04-01

    Full Text Available Hydrogels have emerged as a versatile class of polymeric materials with a wide range of applications in biomedical sciences. The judicious choice of hydrogel precursors allows one to introduce the necessary attributes to these materials that dictate their performance towards intended applications. Traditionally, hydrogels were fabricated using either polymerization of monomers or through crosslinking of polymers. In recent years, dendrimers and dendrons have been employed as well-defined building blocks in these materials. The multivalent and multifunctional nature of dendritic constructs offers advantages in either formulation or the physical and chemical properties of the obtained hydrogels. This review highlights various approaches utilized for the fabrication of hydrogels using well-defined dendrimers, dendrons and their polymeric conjugates. Examples from recent literature are chosen to illustrate the wide variety of hydrogels that have been designed using dendrimer- and dendron-based building blocks for applications, such as sensing, drug delivery and tissue engineering.

  8. Transtuzumab-conjugated liposome-coated fluorscent magnetic namoparticles to target breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Mi Jung; Lee, Hak Jong; Hwang, Sung Il; Yun, Bo La; Kim, Sun Mi [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Yoon, Young Il; Kwon, Yong Soo [Nanoimaging and Therapy Research Center, Institute of Nanoconvergence, Advanced Institutes of Convergence Technology, Seoul National University, Suwon (Korea, Republic of); Yoon, Tae Jong [NanoBio Materials Chemistry Lab., Dept. of Applied Bioscience, CHA University, Pocheon (Korea, Republic of)

    2014-08-15

    To synthesize mesoporous silica-core-shell magnetic nanoparticles (MNPs) encapsulated by liposomes (Lipo [MNPm-SiO{sub 2}]) in order to enhance their stability, allow them to be used in any buffer solution, and to produce trastuzumab-conjugated (Lipo[MNPm-SiO{sub 2}]-Her2Ab) nanoparticles to be utilized in vitro for the targeting of breast cancer. The physiochemical characteristics of Lipo[MNPm-SiO{sub 2}] were assessed in terms of size, morphological features, and in vitro safety. The multimodal imaging properties of the organic dye incorporated into Lipo[MNPm-SiO{sub 2}] were assessed with both in vitro fluorescence and MR imaging. The specific targeting ability of trastuzumab (Her2/neu antibody, Herceptin)-conjugated Lipo[MNPm-SiO{sub 2}] for Her2/neu-positive breast cancer cells was also evaluated with fluorescence and MR imaging. We obtained uniformly-sized and evenly distributed Lipo[MNPm-SiO{sub 2}] that demonstrated biological stability, while not disrupting cell viability. Her2/neu-positive breast cancer cell targeting by trastuzumab-conjugated Lipo[MNPm-SiO{sub 2}] was observed by in vitro fluorescence and MR imaging. Trastuzumab-conjugated Lipo[MNPm-SiO{sub 2}] is a potential treatment tool for targeted drug delivery in Her2/neu-positive breast cancer.

  9. Fluorophore:dendrimer ratio impacts cellular uptake and intracellular fluorescence lifetime.

    Science.gov (United States)

    Dougherty, Casey A; Vaidyanathan, Sriram; Orr, Bradford G; Banaszak Holl, Mark M

    2015-02-18

    G5-NH2-TAMRAn (n = 1-4, 5+, and 1.5(avg)) were prepared with n = 1-4 as a precise dye:dendrimer ratio, 5+ as a mixture of dendrimers with 5 or more dye per dendrimer, and 1.5(avg) as a Poisson distribution of dye:dendrimer ratios with a mean of 1.5 dye per dendrimer. The absorption intensity increased sublinearly with n whereas the fluorescence emission and lifetime decreased with an increasing number of dyes per dendrimer. Flow cytometry was employed to quantify uptake into HEK293A cells. Dendrimers with 2-4 dyes were found to have greater uptake than dendrimer with a single dye. Fluorescence lifetime imaging microscopy (FLIM) showed that the different dye:dendrimer ratio alone was sufficient to change the fluorescence lifetime of the material observed inside cells. We also observed that the lifetime of G5-NH2-TAMRA5+ increased when present in the cell as compared to solution. However, cells treated with G5-NH2-TAMRA1.5(avg) did not exhibit the high lifetime components present in G5-NH2-TAMRA1 and G5-NH2-TAMRA5+. In general, the effects of the dye:dendrimer ratio on fluorescence lifetime were of similar magnitude to environmentally induced lifetime shifts.

  10. Polyphenylene dendrimers

    International Nuclear Information System (INIS)

    Marek, T.

    2002-01-01

    Complete text of publication follows. The most attractive property of polyphenylene dendrimers is their rigidity. They retain the molecular symmetry and monodispersity of the usual, commercially available alyphatic dendrimers, while the composition of the dendritic branches makes them self-supporting. In solution flexible dendrimers usually form a globular 3D-structure in which the dendritic branches are evenly distributed over the whole molecular volume, however, it has been shown that, depending on the generation of the particular dendrimer, their peripheral groups tend to fold back into the interior of the molecule. Moreover, when being adsorbed on a surface (or by the removal of the solvent), they often tend to flatten out. In contrast to this behaviour, it has been shown that rigid dendrimers based on polyphenylenes have stiff branches and the backfolding in solutions is impossible. Furthermore, when polyphenylene dendrimers are absorbed on a mica substrate their original shape is retained. These features and their size, lying in the low nanometer scale, make these molecules attractive candidates for several applications such as supports for functional groups and as hosts for smaller guest molecules. We have studied the free volume in a series of rigid polyphenylene dendrimers by positron lifetime spectroscopy (PLTS) and molecular dynamics calculations, in order to assess the expected relationship between the size (number of generations, molecular weight) of these molecules and the intramolecular free volume. We have found that the size of these inner free volumes is stable, and increases with the increasing number generations

  11. Star-shaped Poly(2-oxazoline)s by Dendrimer Endcapping

    NARCIS (Netherlands)

    Lambermont-Thijs, H.M.L.; Fijten, M.W.M.; Schubert, U.S.; Hoogenboom, R.

    2011-01-01

    The synthesis of star-shaped poly(2-ethyl-2-oxazoline) is reported by direct end-capping of the living polymer chains with dendritic multiamines. The end-capping kinetics after addition of a first generation polypropylenimine dendrimer are discussed based on monitoring by size exclusion

  12. Preparation of Cu Nanoclusters within Dendrimer Templates

    National Research Council Canada - National Science Library

    Zhao, M

    1998-01-01

    ... (16-atom Cu cluster in G4 and 64-atom Cu cluster in G6 dendrimers). The clusters remain trapped within the dendrimers for extended periods of time, do not agglomerate, and do not precipitate. The clusters can also be oxidized to yield dendrimer-encapsulated Cu(2+).

  13. Fluorescent properties of novel dendrimer dyes based on thiazole orange

    International Nuclear Information System (INIS)

    Fei Xuening; Gu Yingchun; Lan Yunquan; Shi Bin

    2011-01-01

    In this paper, polyamidoamine (PAMAM) dendrimers with active amino group of some generations (G=0.5-2) were prepared from commercial aminoacetaldehyde diethyl acetal by the divergent method. After that, thiazole orange (TO) with -COOH was incorporated with dendrimers of G=1 and 2 to afford novel dendrimer-TO dyes. The fluorescent properties studies showed that the fluorescent intensity of the same concentration of dendrimer-TO (G=2) was higher than that of the dendrimer-TO (G=1), and both of them were much stronger than free TO with -COOH. There was a fluorescent enhancement of the dendrimer dyes compared with free dye. The dendrimer dyes were of well-defined chemical structure,with little aggregation and self-quenching as well as good fluorescence properties of good stability, high intensity and sensitivity, which could be used in labeling cancer cells and further in diagnosis and detection of early-stage tumors. - Highlights: → A kind of dendrimer probe based on TO was designed and synthesized. → Dendrimers showed an obvious fluorescence enhancement compared to free dye. → Dendrimers labeled with BSA also showed fluorescence enhancement. → Dendrimers may be used in diagnosis and detection of early-stage tumors.

  14. An improved radiolabelled RNA aptamer molecule for HER2 imaging in cancers.

    Science.gov (United States)

    Varmira, Kambiz; Hosseinimehr, Seyed Jalal; Noaparast, Zohreh; Abedi, Seyed Mohammad

    2014-02-01

    Human epidermal growth factor receptor 2 (HER2) expression has been shown to be increased in several types of human tumours. In this study, for the imaging of HER2-related tumours, a modified RNA aptamer with HER2-specific targeting was labelled with (99m)Tc, by using hydrazino nicotinamide (HYNIC) as the chelator in the presence of tricine or ethylenediamine-N,N'-diacetic acid (EDDA) as the co-ligand. Stability testing of the radiolabelled aptamers in the serum was performed through SDS-PAGE. The aptamer-radionuclide conjugate was evaluated for its cellular HER2-specific binding in ovarian cancer cells (SKOV-3), and its biodistribution properties were assessed in normal and SKOV-3 tumour-bearing mice. In the presence of either tricine or EDDA, the HYNIC-RNA aptamers were labelled with (99m)Tc at a high yield and radiochemical purity. Cellular experiments confirmed the specific binding of the RNA aptamer to the HER2 receptor. In the animal biodistribution study, uptake of the EDDA-co-liganded (99m)Tc-HYNIC-RNA aptamer by the liver and spleen was remarkably lower than that of the aptamer with tricine. Tumours also showed a higher accumulation of radioactivity with the EDDA-co-liganded aptamer complex. This study demonstrated EDDA to be better than tricine for use as a co-ligand with the RNA aptamer, which can be a potential tool for the molecular imaging of HER2-overexpressing cancers.

  15. Light-emitting dendrimer film morphology: A neutron reflectivity study

    Science.gov (United States)

    Vickers, S. V.; Barcena, H.; Knights, K. A.; Thomas, R. K.; Ribierre, J.-C.; Gambino, S.; Samuel, I. D. W.; Burn, P. L.; Fragneto, Giovanna

    2010-06-01

    We have used neutron reflectivity (NR) measurements to probe the physical structure of phosphorescent dendrimer films. The dendrimers consisted of fac-tris(2-phenylpyridyl)iridium(III) cores, biphenyl-based dendrons (first or second generation), and perdeuterated 2-ethylhexyloxy surface groups. We found that the shape and hydrodynamic radius of the dendrimer were both important factors in determining the packing density of the dendrimers. "Cone" shaped dendrimers were found to pack more effectively than "spherical" dendrimers even when the latter had a smaller radius. The morphology of the films determined by NR was consistent with the measured photoluminescence and charge transporting properties of the materials.

  16. Energy transport in dendrimers

    International Nuclear Information System (INIS)

    Supritz, C.; Engelmann, A.; Reineker, P.

    2006-01-01

    Dendrimers are highly branched polymers which are expected to be useful, for example, as efficient artificial light harvesting systems in nano-technological applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers where this distance increases from the system periphery to the center. An open question is still whether energy transport (via Frenkel excitons) occurs in a coherent or incoherent manner. We model the hyperbranched dendrimer molecule as an arrangement of two-level systems and apply the Frenkel exciton concept. The two-level systems are interacting with each other via transfer integrals modeling the special spatial structure of dendrimers. To take into account the electron-phonon interaction we introduce a heat bath that interacts with the exciton in a stochastic manner. In this way we describe the coupled coherent and incoherent Frenkel exciton transport inside a dendrimer. In order to mimic the influence of an energy capturing reaction center (like in photosynthesis) on exciton transport, we attach a sink to the dendrimer core

  17. Energy transport in dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Supritz, C. [Abteilung Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)]. E-mail: christoph.supritz@uni-ulm.de; Engelmann, A. [Abteilung Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany); Reineker, P. [Abteilung Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)

    2006-07-15

    Dendrimers are highly branched polymers which are expected to be useful, for example, as efficient artificial light harvesting systems in nano-technological applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers where this distance increases from the system periphery to the center. An open question is still whether energy transport (via Frenkel excitons) occurs in a coherent or incoherent manner. We model the hyperbranched dendrimer molecule as an arrangement of two-level systems and apply the Frenkel exciton concept. The two-level systems are interacting with each other via transfer integrals modeling the special spatial structure of dendrimers. To take into account the electron-phonon interaction we introduce a heat bath that interacts with the exciton in a stochastic manner. In this way we describe the coupled coherent and incoherent Frenkel exciton transport inside a dendrimer. In order to mimic the influence of an energy capturing reaction center (like in photosynthesis) on exciton transport, we attach a sink to the dendrimer core.

  18. Fluorescein isothiocyanate labeled, magnetic nanoparticles conjugated D-penicillamine-anti-metadherin and in vitro evaluation on breast cancer cells

    International Nuclear Information System (INIS)

    Akca, Ozlet; Unak, Perihan; Medine, E. Ylker; Sakarya, Serhan; Ozdemir, Caglar; Timur, Suna

    2011-01-01

    Silane modified magnetic nanoparticles were prepared after capped with silica generated from the hydrolyzation of tetraethyl orthosilicate (TEOS). Amino silane (SG-Si900) was added to this solution for surface modification of silica coated magnetic particles. Finally, D-penicillamine (D-PA)-antimetadherin (anti-MTDH) was covalently linked to the amine group using glutaraldehyde as cross-linker. Magnetic nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and atomic force microscopy (AFM). AFM results showed that particles are nearly monodisperse, and the average size of particles was 40 to 50 nm. An amino acid derivative D-PA was conjugated anti-MTDH, which results the increase of uptaking potential of a conjugated agent, labelled fluorescein isothiocyanate (FITC) and then conjugated to the magnetic nanoparticles. In vitro evaluation of the conjugated D-PA-anti-MTDH-FITC to magnetic nanoparticle was studied on MCF-7 breast cancer cell lines. Fluorescence microscopy images of cells after incubation of the sample were obtained to monitor the interaction of the sample with the cancerous cells. Incorporation on cells of FITC labeled and magnetic nanoparticles conjugated D-PA-anti-MTDH was found higher than FITC labeled D-PA-anti-MTDH. The results show that magnetic properties and application of magnetic field increased incorporation rates. The obtained D-PA-anti-MTDH-magnetic nanoparticles-FITC complex has been used for in vitro imaging of breast cancer cells. FITC labeled and magnetic nanoparticles conjugated D-PA-anti-MTDH may be useful as a new class of scintigraphic agents. Results of this study are sufficiently encouraging to bring about further evaluation of this and related compounds for ultraviolet magnetic resonance (UV-MR) dual imaging. (author)

  19. antiEGFR conjugated gold nanoparticles for increasing radiosensitivity in lung cancer cells

    International Nuclear Information System (INIS)

    Pujari, Geetanjali; Sarma, Asitikantha; Avasthi, Devesh K.

    2014-01-01

    One of the set back that lies in lung cancer treatment is the over expression of Epidermal Growth Factor Receptor (EGFR). EGFR is a transmembrane receptor that is highly expressed in lung cancer that leads to cell survival, proliferation and spread of the disease. Over the years, EGFR inhibitors, monoclonal antibodies, are being used in combination with radiotherapy in lung cancer patients so as to achieve better results. In the recent time, application of Au nanoparticles (AuNPs) in diagnosis and treatment of cancer has been extensively used in biomedical research. Among various applications, there is considerable use of AuNPs seen on the dose enhancement effect (radiosensitization) in radiation therapy of cancer. The conjugation of AuNP with monoclonal antibody antiEGFR (antiEGFR-AuNP) may provide excellent agent to sensitize the cells to heavy ion radiation. We synthesized AuNPs by citrate reduction method. Most of AuNPs were in the size range of 6-8 nm as studies by Transmission Electron Microscope (TEM). These AuNPs were found to be non toxic in A549 cells and thus biocompatible. Further, we conjugated AuNPs with antiEGFR (antiEGFR-AuNP). The conjugation was confirmed by UV-Vis spectroscopy. A549 cells were treated with antiEGFR-AuNP. TEM was carried out of ultrathin cross sections of antiEGFR-AuNP treated A549 cells to check the attachment internalization of AuNPs. We observed that the AuNPs are attached on the cell membrane as well as internalized in cytoplasm. Upon exposure of antiEGFR-AuNP treated cells to heavy ion 12 C beam, showed increase in radiosensitization as studied by survival assay and MTT assay. We will also explain the EGFR expression and cell cycle proliferation in A549 cells upon heavy ion beam irradiation of these. The study aims to overcome the current limitations of cancer-targeted therapies and improve the treatment modality of lung cancer. (author)

  20. Optical absorption in dendrimers

    International Nuclear Information System (INIS)

    Supritz, C.; Engelmann, A.; Reineker, P.

    2004-01-01

    Dendrimers are highly branched molecules, which are expected to be useful, for example, as efficient artificial light harvesting systems in nano-technological applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers, where this distance increases from the system periphery to the center. We investigate the linear absorption spectra of these dendrimer types using the Frenkel exciton concept. The electron-phonon interaction is taken into account by introducing a heat bath that interacts with the exciton in a stochastic manner

  1. Ordered Layered Dendrimers Constructed from Two Known Dendrimer Families: Inheritance and Emergence of Properties.

    Science.gov (United States)

    Dib, Hanna; Rebout, Cyrille; Laurent, Régis; Mallet-Ladeira, Sonia; Sournia-Saquet, Alix; Sárosi, Menyhárt B; Hey-Hawkins, Evamarie; Majoral, Jean-Pierre; Delavaux-Nicot, Béatrice; Caminade, Anne-Marie

    2016-07-25

    A new concept is presented, namely the synthesis of dendrimers intrinsically composed in alternation of building blocks pertaining to two known families of dendrimers: phosphorhydrazone dendrimers and triazine-piperazine dendrimers. These mixed dendrimers with layered controlled architecture inherit their easy (31) P NMR characterization and their thermal stability from the phosphorhydrazone family, and their decreased solubility from the triazine-piperazine family. However, they have also their own and original characteristics. Both parent families are white powders, whereas the mixed dendrimers are yellow, orange, or red powders, depending on the generation. DFT calculations were carried out on model dendrons to understand these special color features. Remarkably, these dendrimers incorporating redox-active organic entities allow for the first time the monitoring of the growth of an organic dendrimer by electrochemistry while highlighting an even-odd generation behavior. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Paramagnetic NMR investigation of dendrimer-based host-guest interactions.

    Directory of Open Access Journals (Sweden)

    Fei Wang

    Full Text Available In this study, the host-guest behavior of poly(amidoamine (PAMAM dendrimers bearing amine, hydroxyl, or carboxylate surface functionalities were investigated by paramagnetic NMR studies. 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO derivatives were used as paramagnetic guest molecules. The results showed that TEMPO-COOH significantly broaden the ¹H NMR peaks of amine- and hydroxyl-terminated PAMAM dendrimers. In comparison, no paramagnetic relaxation enhancement (PRE was observed between TEMPO-NH₂, TEMPO-OH and the three types of PAMAM dendrimers. The PRE phenomenon observed is correlated with the encapsulation of TEMPO-COOH within dendrimer pockets. Protonation of the tertiary amine groups within PAMAM dendrimers plays an important role during this process. Interestingly, the absence of TEMPO-COOH encapsulation within carboxylate-terminated PAMAM dendrimer is observed due to the repulsion of TEMPO-COO- anion and anionic dendrimer surface. The combination of paramagnetic probes and ¹H NMR linewidth analysis can be used as a powerful tool in the analysis of dendrimer-based host-guest systems.

  3. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    Science.gov (United States)

    Pan, Bifeng; Cui, Daxiang; Xu, Ping; Ozkan, Cengiz; Feng, Gao; Ozkan, Mihri; Huang, Tuo; Chu, Bingfeng; Li, Qing; He, Rong; Hu, Guohan

    2009-03-01

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH2-asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  4. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Pan Bifeng; Cui Daxiang; Xu Ping; Feng Gao; Huang Tuo; Li Qing; He Rong [Department of Bio-Nano-Science and Engineering, National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Institute of Micro-Nano Science and Technology, Shanghai JiaoTong University, 800 Dongchuan Road, Shanghai 200240 (China); Ozkan, Cengiz [Mechanical Engineering Department, University of California Riverside, 900 University Avenue-Riverside, CA 92521 (United States); Ozkan, Mihri [Electrical Engineering Department, University of California Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Chu, Bingfeng [Department of Stomatology, General Hospital of PLA, 28 Fuxing Road, Beijing100853 (China); Hu Guohan [Department of Neurosurgery of Changzheng Hospital, 415 Fengyang Road, Second Military Medical University, Shanghai 20003 (China)], E-mail: dxcui@sjtu.edu.cn, E-mail: huguohan6504@sina.com

    2009-03-25

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH{sub 2}-asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  5. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    International Nuclear Information System (INIS)

    Pan Bifeng; Cui Daxiang; Xu Ping; Feng Gao; Huang Tuo; Li Qing; He Rong; Ozkan, Cengiz; Ozkan, Mihri; Chu, Bingfeng; Hu Guohan

    2009-01-01

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH 2 -asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  6. Nanomedicine for prion disease treatment: new insights into the role of dendrimers.

    Science.gov (United States)

    McCarthy, James M; Appelhans, Dietmar; Tatzelt, Jörg; Rogers, Mark S

    2013-01-01

    Despite their devastating impact, no effective therapeutic yet exists for prion diseases at the symptomatic stage in humans or animals. Progress is hampered by the difficulty in identifying compounds that affect PrP (Sc) and the necessity of any potential therapeutic to gain access to the CNS. Synthetic polymers known as dendrimers are a particularly promising candidate in this area. Studies with cell culture models of prion disease and prion infected brain homogenate have demonstrated that numerous species of dendrimers eliminate PrP (Sc) in a dose and time dependent fashion and specific glycodendrimers are capable of crossing the CNS. However, despite their potential a number of important questions remained unanswered such as what makes an effective dendrimer and how dendrimers eliminate prions intracellularly. In a number of recent studies we have tackled these questions and revealed for the first time that a specific dendrimer can inhibit the intracellular conversion of PrP (C) to PrP (Sc) and that a high density of surface reactive groups is a necessity for dendrimers in vitro anti-prion activity. Understanding how a therapeutic works is a vital component in maximising its activity and these studies therefore represent a significant development in the race to find effective treatments for prion diseases.

  7. Toxicity of PAMAM dendrimers to Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Petit, Anne-Noelle; Eullaffroy, Philippe; Debenest, Timothee; Gagne, Francois

    2010-01-01

    In recent decades, a new class of polymeric materials, PAMAM dendrimers, has attracted marked interest owing to their unique nanoscopic architecture and their hopeful perspectives in nanomedicine and therapeutics. However, the potential release of dendrimers into the aquatic environment raises the issue about their toxicity on aquatic organisms. Our investigation sought to estimate the toxicity of cationic PAMAM dendrimers on the green alga, Chlamydomonas reinhardtii. Algal cultures were exposed to different concentrations (0.3-10 mg L -1 ) of low dendrimer generations (G2, G4 and G5) for 72 h. Potential adverse effects on Chlamydomonas were assessed using esterase activity (cell viability), photosynthetic O 2 evolution, pigments content and chlorophyll a fluorescence transient. According to the median inhibitory concentration (IC 50 ) appraised from esterase activity, toxicity on cell viability decreased with dendrimer generation number (2, 3 and 5 mg L -1 for G2, G4 and G5 dendrimers, respectively). Moreover, the three generations of dendrimers did not induce the same changes in the photosynthetic metabolism of the green alga. O 2 evolution was stimulated in cultures exposed to the lowest generations tested (i.e. G2 and G4) whereas no significant effects were observed with G5. In addition, total chlorophyll content was increased after G2 treatment at 2.5 mg L -1 . Finally, G2 and G4 had positive effects on photosystem II (PSII): the amount of active PSII reaction centers, the primary charge separation and the electron transport between Q A and Q B were all increased inducing activation of the photosynthetic electron transport chain. These changes resulted in stimulation of full photosynthetic performance.

  8. A polyamidoamine dendrimer-streptavidin supramolecular architecture for biosensor development.

    Science.gov (United States)

    Soda, N; Arotiba, O A

    2017-12-01

    A novel polyamidoamine dendrimer-streptavidin supramolecular architecture suitable as a versatile platform for biosensor development is reported. The dendrimer was electrodeposited on a glassy carbon electrode via cyclic voltammetry. The dendrimer electrode was further modified with streptavidin by electrostatic attraction upon drop coating. The platform i.e. the dendrimer-streptavidin modified electrode was electrochemically interrogated in phosphate buffer, ferrocyanide and H 2 O 2 . The dendrimer-streptavidin platform was used in the preparation of a simple DNA biosensor as a proof of concept. The supramolecular architecture of dendrimer-streptavidin was stable, electroactive and thus lends itself as a versatile immobilisation layer for any biotinylated bioreceptors in biosensor development. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. HER2 signaling pathway activation and response of breast cancer cells to HER2-targeting agents is dependent strongly on the 3D microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Weigelt, Britta; Lo, Alvin T; Park, Catherine C; Gray, Joe W; Bissell, Mina J

    2009-07-27

    Development of effective and durable breast cancer treatment strategies requires a mechanistic understanding of the influence of the microenvironment on response. Previous work has shown that cellular signaling pathways and cell morphology are dramatically influenced by three-dimensional (3D) cultures as opposed to traditional two-dimensional (2D) monolayers. Here, we compared 2D and 3D culture models to determine the impact of 3D architecture and extracellular matrix (ECM) on HER2 signaling and on the response of HER2-amplified breast cancer cell lines to the HER2-targeting agents Trastuzumab, Pertuzumab and Lapatinib. We show that the response of the HER2-amplified AU565, SKBR3 and HCC1569 cells to these anti-HER2 agents was highly dependent on whether the cells were cultured in 2D monolayer or 3D laminin-rich ECM gels. Inhibition of {beta}1 integrin, a major cell-ECM receptor subunit, significantly increased the sensitivity of the HER2-amplified breast cancer cell lines to the humanized monoclonal antibodies Trastuzumab and Pertuzumab when grown in a 3D environment. Finally, in the absence of inhibitors, 3D cultures had substantial impact on HER2 downstream signaling and induced a switch between PI3K-AKT- and RAS-MAPKpathway activation in all cell lines studied, including cells lacking HER2 amplification and overexpression. Our data provide direct evidence that breast cancer cells are able to rapidly adapt to different environments and signaling cues by activating alternative pathways that regulate proliferation and cell survival, events that may play a significant role in the acquisition of resistance to targeted therapies.

  10. New dendrimer - Peptide host - Guest complexes: Towards dendrimers as peptide carriers

    DEFF Research Database (Denmark)

    Boas, Ulrik; Sontjens, S.H.M.; Jensen, Knud Jørgen

    2002-01-01

    Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions...... between the dendrimer outer shell tertiary amines and the C-terminal carboxylic acid of the peptide, and also through host-urea to peptide-amide hydrogen bonding. The hydrogen-bonding nature of the peptide dendrimer interactions was further confirmed by using Fourier transform IR spectroscopy, for which...... the NH- and CO-stretch signals of the peptide amide moieties shift towards lower wave-numbers upon complexation with the dendrimer. Spatial analysis of the complexes with NOESY spectroscopy generally shows close proximity of the N-terminal Boc group of the peptide to the peripheral adamantyl groups...

  11. Dendrimers and polyamino-phenolic ligands: activity of new molecules against Legionella pneumophila biofilms.

    Directory of Open Access Journals (Sweden)

    Elisa eAndreozzi

    2016-03-01

    Full Text Available Legionnaires’ disease is a potentially fatal pneumonia caused by Legionella pneumophila, an aquatic bacterium often found within the biofilm niche. In man-made water systems microbial biofilms increase the resistance of legionella to disinfection, posing a significant threat to public health. Disinfection methods currently used in water systems have been shown to be ineffective against legionella over the long-term, allowing recolonization by the biofilm-protected microorganisms. In this study, the anti-biofilm activity of previously fabricated polyamino-phenolic ligands and polyamidoamine dendrimers was investigated against legionella mono-species and multi-species biofilms formed by L. pneumophila in association with other bacteria that can be found in tap water (Aeromonas hydrophila, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae. Bacterial ability to form biofilms was verified using a crystal violet colorimetric assay and testing cell viability by real-time quantitative PCR and Plate Count assay. The concentration of the chemicals tested as anti-biofilm agents was chosen based on cytotoxicity assays: the highest non-cytotoxic chemical concentration was used for biofilm inhibition assays, with dendrimer concentration ten-fold higher than polyamino-phenolic ligands. While Macrophen and Double Macrophen were the most active substances among polyamino-phenolic ligands, dendrimers were overall two-fold more effective than all other compounds with a reduction up to 85% and 73% of legionella and multi-species biofilms, respectively. Chemical interaction with matrix molecules is hypothesized, based on SEM images and considering the low or absent anti-microbial activity on planktonic bacteria showed by flow cytometry. These data suggest that the studied compounds, especially dendrimers, could be considered as novel molecules in the design of research projects aimed at the development of efficacious anti-biofilm disinfection

  12. Validation of the 4B5 rabbit monoclonal antibody in determining Her2/neu status in breast cancer

    NARCIS (Netherlands)

    van der Vegt, Bert; de Bock, G.H.; Bart, J.; Zwartjes, N.G.; Wesseling, J.

    HER2 overexpression in breast cancer is associated with worse clinical outcome. To select patients for anti-Her2-based therapy immunohistochemistry is commonly performed as a first step to assess Her2 status. However, interobserver and interlaboratory variability can significantly compromise

  13. Fluorescence polarization measures energy funneling in single light-harvesting antennas--LH2 vs conjugated polymers.

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J; Sforazzini, Giuseppe; Anderson, Harry L; Pullerits, Tõnu; Scheblykin, Ivan G

    2015-10-19

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  14. Selective cytotoxicity of PAMAM G5 core–PAMAM G2.5 shell tecto-dendrimers on melanoma cells

    Directory of Open Access Journals (Sweden)

    Schilrreff P

    2012-07-01

    Full Text Available Priscila Schilrreff,1 Cecilia Mundiña-Weilenmann,2 Eder Lilia Romero,1 Maria Jose Morilla11Programa de Nanomedicinas, Universidad Nacional de Quilmes, Buenos Aires, Argentina; 2Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata, La Plata, ArgentinaBackground: The controlled introduction of covalent linkages between dendrimer building blocks leads to polymers of higher architectural order known as tecto-dendrimers. Because of the few simple steps involved in their synthesis, tecto-dendrimers could expand the portfolio of structures beyond commercial dendrimers, due to the absence of synthetic drawbacks (large number of reaction steps, excessive monomer loading, and lengthy chromatographic separations and structural constraints of high-generation dendrimers (reduction of good monodispersity and ideal dendritic construction due to de Gennes dense-packing phenomenon. However, the biomedical uses of tecto-dendrimers remain unexplored. In this work, after synthesizing saturated shell core–shell tecto-dendrimers using amine-terminated polyamidoamine (PAMAM generation 5 (G5 as core and carboxyl-terminated PAMAM G2.5 as shell (G5G2.5 tecto-dendrimers, we surveyed for the first time the main features of their interaction with epithelial cells.Methods: Structural characterization of G5G2.5 was performed by polyacrylamide gel electrophoresis, matrix-assisted laser desorption time-of-flight mass spectrometry, and microscopic techniques; their hydrodynamic size and Z-potential was also determined. Cellular uptake by human epidermal keratinocytes, colon adenocarcinoma, and epidermal melanoma (SK-Mel-28 cells was determined by flow cytometry. Cytotoxicity was determined by mitochondrial activity, lactate dehydrogenase release, glutathione depletion, and apoptosis/necrosis measurement.Results: The resultant 60%–67% saturated shell, 87,000-dalton G5G2.5 (mean molecular weight interacted with cells in a significantly different

  15. Plant virus-resembling optical nano-materials conjugated with anti-EGFR for targeted cancer imaging

    Science.gov (United States)

    Gupta, Sharad; Wilder, Hailey; Rao, A. L. N.; Vullev, V. I.; Anvari, Bahman

    2012-03-01

    We recently reported the construction of a new type of optically active nano-particles composed of genome-depleted plant infecting brome mosaic virus (BMV) doped with indocyanine green (ICG), an FDA-approved chromophore . We refer to these constructs as optical viral ghosts (OVGs) since only the capsid protein (CP) subunits of BMV remain to encapsulate ICG. Herein, we covalently conjugated the surface of OVGs with anti-epidermal growth factor receptors (anti-EGFR) to target cancerous human bronchial epithelial cells (C-HBECs) in-vitro. Our preliminary results demonstrate the utility of conjugated OVGs for targeted imaging of cancer cells.

  16. HER-2 Pulsed Dendritic Cell Vaccine Can Eliminate HER-2 Expression and Impact DCIS

    Science.gov (United States)

    Sharma, Anupama; Koldovsky, Ursula; Xu, Shuwen; Mick, Rosemarie; Roses, Robert; Fitzpatrick, Elizabeth; Weinstein, Susan; Nisenbaum, Harvey; Levine, Bruce L; Fox, Kevin; Zhang, Paul; Koski, Gary; Czerniecki, Brian J

    2011-01-01

    Background HER-2/neu over-expression plays a critical role in breast cancer development and its expression in ductal carcinoma in situ (DCIS) is associated with development of invasive breast cancer. A vaccine targeting HER-2/neu expression in DCIS may initiate immunity against invasive cancer. Methods A HER-2/neu dendritic cell (DC) vaccine was administered to 27 patients with HER-2/neu over-expressing DCIS. The HER-2/neu vaccine was administered prior to surgical resection and pre- and post-vaccination analysis was conducted to assess clinical results. Results At surgery, 5 of 27 (18.5%) vaccinated subjects had no evidence of remaining disease, while among 22 subjects with residual DCIS, HER-2/neu expression was eradicated in 11 (50%). When comparing ERneg with ERpos DCIS lesions, vaccination was more effective in hormone-independent DCIS. Following vaccination, no residual DCIS was found in 40% of ERneg subjects compared to 5.9% in ERpos subject. Sustained HER-2/neu expression was found in 10% of ERneg subjects compared to 47.1% in ERpos subjects (p=0.04). Post-vaccination phenotypes were significantly different between ERpos and ERneg subjects (p=0.01), with 7 of 16 (43.8%) initially presenting with ERpos HER-2/neupos Luminal B phenotype finishing with the ERpos HER-2/neuneg Luminal A phenotype, and 3 of 6 (50%) with the ERneg HER-2/neupos phenotype changing to the ERneg HER-2/neuneg phenotype. Conclusions Results suggest vaccination against HER-2/neu is safe, well-tolerated and induces decline and or eradication of HER-2/neu expression. These findings warrant further exploration of HER-2/neu vaccination in estrogen-independent breast cancer and highlight the need to target additional tumor associated antigens and pathways. PMID:22252842

  17. Highly sensitive dendrimer-based nanoplasmonic biosensor for drug allergy diagnosis.

    Science.gov (United States)

    Soler, Maria; Mesa-Antunez, Pablo; Estevez, M-Carmen; Ruiz-Sanchez, Antonio Jesus; Otte, Marinus A; Sepulveda, Borja; Collado, Daniel; Mayorga, Cristobalina; Torres, Maria Jose; Perez-Inestrosa, Ezequiel; Lechuga, Laura M

    2015-04-15

    A label-free biosensing strategy for amoxicillin (AX) allergy diagnosis based on the combination of novel dendrimer-based conjugates and a recently developed nanoplasmonic sensor technology is reported. Gold nanodisks were functionalized with a custom-designed thiol-ending-polyamido-based dendron (d-BAPAD) peripherally decorated with amoxicilloyl (AXO) groups (d-BAPAD-AXO) in order to detect specific IgE generated in patient's serum against this antibiotic during an allergy outbreak. This innovative strategy, which follows a simple one-step immobilization procedure, shows exceptional results in terms of sensitivity and robustness, leading to a highly-reproducible and long-term stable surface which allows achieving extremely low limits of detection. Moreover, the viability of this biosensor approach to analyze human biological samples has been demonstrated by directly analyzing and quantifying specific anti-AX antibodies in patient's serum without any sample pretreatment. An excellent limit of detection (LoD) of 0.6ng/mL (i.e. 0.25kU/L) has been achieved in the evaluation of clinical samples evidencing the potential of our nanoplasmonic biosensor as an advanced diagnostic tool to quickly identify allergic patients. The results have been compared and validated with a conventional clinical immunofluorescence assay (ImmunoCAP test), confirming an excellent correlation between both techniques. The combination of a novel compact nanoplasmonic platform and a dendrimer-based strategy provides a highly sensitive label free biosensor approach with over two times better detectability than conventional SPR. Both the biosensor device and the carrier structure hold great potential in clinical diagnosis for biomarker analysis in whole serum samples and other human biological samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Dendrimer Brain Uptake and Targeted Therapy for Brain Injury in a Large Animal Model of Hypothermic Circulatory Arrest

    Science.gov (United States)

    2015-01-01

    Treatment of brain injury following circulatory arrest is a challenging health issue with no viable therapeutic options. Based on studies in a clinically relevant large animal (canine) model of hypothermic circulatory arrest (HCA)-induced brain injury, neuroinflammation and excitotoxicity have been identified as key players in mediating the brain injury after HCA. Therapy with large doses of valproic acid (VPA) showed some neuroprotection but was associated with adverse side effects. For the first time in a large animal model, we explored whether systemically administered polyamidoamine (PAMAM) dendrimers could be effective in reaching target cells in the brain and deliver therapeutics. We showed that, upon systemic administration, hydroxyl-terminated PAMAM dendrimers are taken up in the brain of injured animals and selectively localize in the injured neurons and microglia in the brain. The biodistribution in other major organs was similar to that seen in small animal models. We studied systemic dendrimer–drug combination therapy with two clinically approved drugs, N-acetyl cysteine (NAC) (attenuating neuroinflammation) and valproic acid (attenuating excitotoxicity), building on positive outcomes in a rabbit model of perinatal brain injury. We prepared and characterized dendrimer-NAC (D-NAC) and dendrimer-VPA (D-VPA) conjugates in multigram quantities. A glutathione-sensitive linker to enable for fast intracellular release. In preliminary efficacy studies, combination therapy with D-NAC and D-VPA showed promise in this large animal model, producing 24 h neurological deficit score improvements comparable to high dose combination therapy with VPA and NAC, or free VPA, but at one-tenth the dose, while significantly reducing the adverse side effects. Since adverse side effects of drugs are exaggerated in HCA, the reduced side effects with dendrimer conjugates and suggestions of neuroprotection offer promise for these nanoscale drug delivery systems. PMID:24499315

  19. Toxicity of PAMAM dendrimers to Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Anne-Noelle, E-mail: anne-noelle.petit@ec.gc.ca [Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7 (Canada); Eullaffroy, Philippe [Laboratoire Plantes, Pesticides et Developpement Durable, EA 2069, URVVC, BP 1039, Universite de Reims Champagne-Ardenne, 51687 Reims Cedex 2 (France); Debenest, Timothee; Gagne, Francois [Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7 (Canada)

    2010-10-15

    In recent decades, a new class of polymeric materials, PAMAM dendrimers, has attracted marked interest owing to their unique nanoscopic architecture and their hopeful perspectives in nanomedicine and therapeutics. However, the potential release of dendrimers into the aquatic environment raises the issue about their toxicity on aquatic organisms. Our investigation sought to estimate the toxicity of cationic PAMAM dendrimers on the green alga, Chlamydomonas reinhardtii. Algal cultures were exposed to different concentrations (0.3-10 mg L{sup -1}) of low dendrimer generations (G2, G4 and G5) for 72 h. Potential adverse effects on Chlamydomonas were assessed using esterase activity (cell viability), photosynthetic O{sub 2} evolution, pigments content and chlorophyll a fluorescence transient. According to the median inhibitory concentration (IC{sub 50}) appraised from esterase activity, toxicity on cell viability decreased with dendrimer generation number (2, 3 and 5 mg L{sup -1} for G2, G4 and G5 dendrimers, respectively). Moreover, the three generations of dendrimers did not induce the same changes in the photosynthetic metabolism of the green alga. O{sub 2} evolution was stimulated in cultures exposed to the lowest generations tested (i.e. G2 and G4) whereas no significant effects were observed with G5. In addition, total chlorophyll content was increased after G2 treatment at 2.5 mg L{sup -1}. Finally, G2 and G4 had positive effects on photosystem II (PSII): the amount of active PSII reaction centers, the primary charge separation and the electron transport between Q{sub A} and Q{sub B} were all increased inducing activation of the photosynthetic electron transport chain. These changes resulted in stimulation of full photosynthetic performance.

  20. A gene expression signature of Retinoblastoma loss-of-function predicts resistance to neoadjuvant chemotherapy in ER-positive/HER2-positive breast cancer patients.

    Science.gov (United States)

    Risi, Emanuela; Grilli, Andrea; Migliaccio, Ilenia; Biagioni, Chiara; McCartney, Amelia; Guarducci, Cristina; Bonechi, Martina; Benelli, Matteo; Vitale, Stefania; Biganzoli, Laura; Bicciato, Silvio; Di Leo, Angelo; Malorni, Luca

    2018-07-01

    HER2-positive (HER2+) breast cancers show heterogeneous response to chemotherapy, with the ER-positive (ER+) subgroup deriving less benefit. Loss of retinoblastoma tumor suppressor gene (RB1) function has been suggested as a cardinal feature of breast cancers that are more sensitive to chemotherapy and conversely resistant to CDK4/6 inhibitors. We performed a retrospective analysis exploring RBsig, a gene signature of RB loss, as a potential predictive marker of response to neoadjuvant chemotherapy in ER+/HER2+ breast cancer patients. We selected clinical trials of neoadjuvant chemotherapy ± anti-HER2 therapy in HER2+ breast cancer patients with available information on gene expression data, hormone receptor status, and pathological complete response (pCR) rates. RBsig expression was computed in silico and correlated with pCR. Ten studies fulfilled the inclusion criteria and were included in the analysis (514 patients). Overall, of 211 ER+/HER2+ breast cancer patients, 49 achieved pCR (23%). The pCR rate following chemotherapy ± anti-HER2 drugs in patients with RBsig low expression was significantly lower compared to patients with RBsig high expression (16% vs. 30%, respectively; Fisher's exact test p = 0.015). The area under the ROC curve (AUC) was 0.62 (p = 0.005). In the 303 ER-negative (ER-)/HER2+ patients treated with chemotherapy ± anti-HER2 drugs, the pCR rate was 43%. No correlation was found between RBsig expression and pCR rate in this group. Low expression of RBsig identifies a subset of ER+/HER2+ patients with low pCR rates following neoadjuvant chemotherapy ± anti-HER2 therapy. These patients may potentially be spared chemotherapy in favor of anti-HER2, endocrine therapy, and CDK 4/6 inhibitor combinations.

  1. Dendrimers: relationship between structure and biocompatibility in vitro, and preliminary studies on the biodistribution of 125I-labelled polyamidoamine dendrimers in vivo.

    Science.gov (United States)

    Malik, N; Wiwattanapatapee, R; Klopsch, R; Lorenz, K; Frey, H; Weener, J W; Meijer, E W; Paulus, W; Duncan, R

    2000-03-01

    Dendrimers are highly branched macromolecules of low polydispersity that provide many exciting opportunities for design of novel drug-carriers, gene delivery systems and imaging agents. They hold promise in tissue targeting applications, controlled drug release and moreover, their interesting nanoscopic architecture might allow easier passage across biological barriers by transcytosis. However, from the vast array of structures currently emerging from synthetic chemistry it is essential to design molecules that have real potential for in vivo biological use. Here, polyamidoamine (PAMAM, Starburst), poly(propyleneimine) with either diaminobutane or diaminoethane as core, and poly(ethylene oxide) (PEO) grafted carbosilane (CSi-PEO) dendrimers were used to study systematically the effect of dendrimer generation and surface functionality on biological properties in vitro. Generally, dendrimers bearing -NH(2) termini displayed concentration- and in the case of PAMAM dendrimers generation-dependent haemolysis, and changes in red cell morphology were observed after 1 h even at low concentrations (10 microg/ml). At concentrations below 1 mg/ml CSi-PEO dendrimers and those dendrimers with carboxylate (COONa) terminal groups were neither haemolytic nor cytotoxic towards a panel of cell lines in vitro. In general, cationic dendrimers were cytotoxic (72 h incubation), displaying IC(50) values=50-300 microg/ml dependent on dendrimer-type, cell-type and generation. Preliminary studies with polyether dendrimers prepared by the convergent route showed that dendrimers with carboxylate and malonate surfaces were not haemolytic at 1 h, but after 24 h, unlike anionic PAMAM dendrimers they were lytic. Cationic 125I-labelled PAMAM dendrimers (gen 3 and 4) administered intravenously (i.v.) to Wistar rats ( approximately 10 microg/ml) were cleared rapidly from the circulation (<2% recovered dose in blood at 1 h). Anionic PAMAM dendrimers (gen 2.5, 3.5 and 5.5) showed longer circulation

  2. Intracellular Ca2+ release mediates cationic but not anionic poly(amidoamine) (PAMAM) dendrimer-induced tight junction modulation.

    Science.gov (United States)

    Avaritt, Brittany R; Swaan, Peter W

    2014-09-01

    Poly(amidoamine) (PAMAM) dendrimers show great promise for utilization as oral drug delivery vehicles. These polymers are capable of traversing epithelial barriers, and have been shown to translocate by both transcellular and paracellular routes. While many proof-of-concept studies have shown that PAMAM dendrimers improve intestinal transport, little information exists on the mechanisms of paracellular transport, specifically dendrimer-induced tight junction modulation. Using anionic G3.5 and cationic G4 PAMAM dendrimers with known absorption enhancers, we investigated tight junction modulation in Caco-2 monolayers by visualization and mannitol permeability and compared dendrimer-mediated tight junction modulation to that of established permeation enhancers. [(14)C]-Mannitol permeability in the presence and absence of phospholipase C-dependent signaling pathway inhibitors was also examined and indicated that this pathway may mediate dendrimer-induced changes in permeability. Differences between G3.5 and G4 in tight junction protein staining and permeability with inhibitors were evident, suggesting divergent mechanisms were responsible for tight junction modulation. These dissimilarities are further intimated by the intracellular calcium release caused by G4 but not G3.5. Based on our results, it is apparent that the underlying mechanisms of dendrimer permeability are complex, and the complexities are likely a result of the density and sign of the surface charges of PAMAM dendrimers. The results of this study will have implications on the future use of PAMAM dendrimers for oral drug delivery.

  3. DNA condensation by partially acetylated poly(amido amine) dendrimers: effects of dendrimer charge density on complex formation.

    Science.gov (United States)

    Yu, Shi; Li, Ming-Hsin; Choi, Seok Ki; Baker, James R; Larson, Ronald G

    2013-09-03

    The ability of poly(amido amine) (or PAMAM) dendrimers to condense semiflexible dsDNA and penetrate cell membranes gives them great potential in gene therapy and drug delivery but their high positive surface charge makes them cytotoxic. Here, we describe the effects of partial neutralization by acetylation on DNA condensation using light scattering, circular dichroism, and single molecule imaging of dendrimer-DNA complexes combed onto surfaces and tethered to those surfaces under flow. We find that DNA can be condensed by generation-five (G5) dendrimers even when the surface charges are more than 65% neutralized, but that such dendrimers bind negligibly when an end-tethered DNA is stretched in flow. We also find that when fully charged dendrimers are introduced by flow to end-tethered DNA, all DNA molecules become equally highly coated with dendrimers at a rate that becomes very fast at high dendrimer concentration, and that dendrimers remain bound during subsequent flow of dendrimer-free buffer. These results suggest that the presence of dendrimer-free DNA coexisting with dendrimer-bound DNA after bulk mixing of the two in solution may result from diffusion-limited irreversible dendrimer-DNA binding, rather than, or in addition to, the previously proposed cooperative binding mechanism of dendrimers to DNA.

  4. DNA Condensation by Partially Acetylated Poly(amido amine Dendrimers: Effects of Dendrimer Charge Density on Complex Formation

    Directory of Open Access Journals (Sweden)

    Ronald G. Larson

    2013-09-01

    Full Text Available The ability of poly(amido amine (or PAMAM dendrimers to condense semiflexible dsDNA and penetrate cell membranes gives them great potential in gene therapy and drug delivery but their high positive surface charge makes them cytotoxic. Here, we describe the effects of partial neutralization by acetylation on DNA condensation using light scattering, circular dichroism, and single molecule imaging of dendrimer-DNA complexes combed onto surfaces and tethered to those surfaces under flow. We find that DNA can be condensed by generation-five (G5 dendrimers even when the surface charges are more than 65% neutralized, but that such dendrimers bind negligibly when an end-tethered DNA is stretched in flow. We also find that when fully charged dendrimers are introduced by flow to end-tethered DNA, all DNA molecules become equally highly coated with dendrimers at a rate that becomes very fast at high dendrimer concentration, and that dendrimers remain bound during subsequent flow of dendrimer-free buffer. These results suggest that the presence of dendrimer-free DNA coexisting with dendrimer-bound DNA after bulk mixing of the two in solution may result from diffusion-limited irreversible dendrimer-DNA binding, rather than, or in addition to, the previously proposed cooperative binding mechanism of dendrimers to DNA.

  5. Thin film properties of triphenylamine-cored dendrimers: A molecular approach to control aggregation

    International Nuclear Information System (INIS)

    Vamvounis, George; Pivrikas, Almantas; Shaw, Paul E.; Burn, Paul L.

    2013-01-01

    The solid-state photophysical and charge transport properties of two first-generation dendrimers are presented. The dendrimers are comprised of a triphenylamine core, dendrons containing a phenyl branching unit with thiophene (Dendrimer 1) or bithiophene (Dendrimer 2) moieties, and dodecyl surface groups. For Dendrimer 1, the excited state is located within the center of the dendrimer giving rise to a moderate solid-state photoluminescence quantum yield (Φ pl ) (0.13) and significant charge trapping, with both observations due to the degree of overlap of the main electroactive chromophores on adjacent dendrimers. For Dendrimer 2, the excited state is located within the dendron and in the solid-state this leads to a strongly red-shifted and weakened emission (Φ pl ∼ 0.02) due to strong intermolecular chromophore interactions. For films of Dendrimer 2 the charge mobility was higher than Dendrimer 1 but was still limited by a low density of strongly interacting electroactive chromophores. The pronounced difference between the solid-state properties of the two dendrimers is simply engineered by the addition of an extra thiophene in each of the dendrons. - Highlights: • Photophysical and charge-transport properties of two dendrimers are investigated. • Excited-state is on the center for Dendrimer 1 and on the dendron for Dendrimer 2. • Film quantum yield of luminescence is higher for Dendrimer 1. • Dendrimer 1 displays greater charge trapping at high fields

  6. Dendrimer Prodrugs

    Directory of Open Access Journals (Sweden)

    Soraya da Silva Santos

    2016-05-01

    Full Text Available The main objective of this review is to describe the importance of dendrimer prodrugs in the design of new drugs, presenting numerous applications of these nanocomposites in the pharmaceutical field. Therefore, the use of dendrimer prodrugs as carrier for drug delivery, to improve pharmacokinetic properties of prototype, to promote drug sustained-release, to increase selectivity and, consequently, to decrease toxicity, are just some examples of topics that have been extensively reported in the literature, especially in the last decade. The examples discussed here give a panel of the growing interest dendrimer prodrugs have been evoking in the scientific community.

  7. Computer simulations of dendrimer-polyelectrolyte complexes.

    Science.gov (United States)

    Pandav, Gunja; Ganesan, Venkat

    2014-08-28

    We carry out a systematic analysis of static properties of the clusters formed by complexation between charged dendrimers and linear polyelectrolyte (LPE) chains in a dilute solution under good solvent conditions. We use single chain in mean-field simulations and analyze the structure of the clusters through radial distribution functions of the dendrimer, cluster size, and charge distributions. The effects of LPE length, charge ratio between LPE and dendrimer, the influence of salt concentration, and the dendrimer generation number are examined. Systems with short LPEs showed a reduced propensity for aggregation with dendrimers, leading to formation of smaller clusters. In contrast, larger dendrimers and longer LPEs lead to larger clusters with significant bridging. Increasing salt concentration was seen to reduce aggregation between dendrimers as a result of screening of electrostatic interactions. Generally, maximum complexation was observed in systems with an equal amount of net dendrimer and LPE charges, whereas either excess LPE or dendrimer concentrations resulted in reduced clustering between dendrimers.

  8. Host-guest chemistry of dendrimer-drug complexes. 6. Fully acetylated dendrimers as biocompatible drug vehicles using dexamethasone 21-phosphate as a model drug.

    Science.gov (United States)

    Yang, Kun; Weng, Liang; Cheng, Yiyun; Zhang, Hongfeng; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen

    2011-03-17

    Fully acetylated poly(amidoamine) (PAMAM) dendrimer was proposed as a biocompatible drug vehicle using dexamethasone 21-phosphate (Dp21) as a model drug. NMR techniques including (1)H NMR and 2D NOE NMR were used to characterize the host-guest chemistry of acetylated dendrimer/Dp21 and cationic dendrimer/Dp21 complexes. The pH-dependent micellization, complexation, and inclusion behaviors of Dp21 were observed in the presence of acetylated and cationic PAMAM dendrimers. Acetylated dendrimer only encapsulates Dp21 at acidic conditions, while cationic dendrimer can host Dp21 at both acidic and neutral conditions. The orientation of Dp21 molecules in the dendrimer cavities depends on the quaternization degree of tertiary amine groups of dendrimer and the protonation ratio of phosphate group of Dp21. A distinctive pH-dependent release behavior of Dp21 from the acetylated and nonacetylated dendritic matrix was observed: Dp21 exhibits a much slower release rate from acetylated dendrimer at lower pH conditions and a much faster release rate from nonacetylated dendrimer with decreasing pH values. Cytotoxicity studies further confirmed the biocompatibility of acetylated dendrimers, which are much safer in the delivery of therapeutics for the treatment of various diseases than nonacetylated dendrimers. The dendrimer-drug binding and release mechanisms provide a new insight for the design and optimization of biocompatible dendrimer-based drug delivery systems. © 2011 American Chemical Society

  9. In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Daldrup-Link, Heike E.; Meier, Reinhardt; Metz, Stephan; Settles, Marcus; Rummeny, Ernst J.; Rudelius, Martina; Piontek, Guido; Schlegel, Juergen; Piert, Morand; Uherek, Christoph; Wels, Winfried

    2005-01-01

    The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P 6 NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5 x 10 6 parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently labeled with clinically applicable iron-oxide contrast

  10. In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Daldrup-Link, Heike E. [UCSF Medical Center, Department of Radiology, San Francisco, CA (United States); Meier, Reinhardt; Metz, Stephan; Settles, Marcus; Rummeny, Ernst J. [Technical University Munich, Department of Radiology, Munich (Germany); Rudelius, Martina; Piontek, Guido; Schlegel, Juergen [Technical University Munich, Institute of Pathology, Division of Neuropathology, Munich (Germany); Piert, Morand [Technical University Munich, Department of Nuclear Medicine, Munich (Germany); Uherek, Christoph; Wels, Winfried [University of Frankfurt, Georg Speyer House, Frankfurt (Germany)

    2005-01-01

    The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P<0.05). After intravenous injection of 5 x 10{sup 6} NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5 x 10{sup 6} parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently

  11. Fetal uptake of intra-amniotically delivered dendrimers in a mouse model of intrauterine inflammation and preterm birth.

    Science.gov (United States)

    Burd, Irina; Zhang, Fan; Dada, Tahani; Mishra, Manoj K; Borbiev, Talaibek; Lesniak, Wojciech G; Baghlaf, Haitham; Kannan, Sujatha; Kannan, Rangaramanujam M

    2014-08-01

    Intrauterine inflammation is associated with preterm birth and can lead to fetal neuroinflammation and neurobehavioral disorders in newborns. Dendrimers can intrinsically target and deliver drugs for the treatment of neuroinflammation. We explore whether hydroxyl polyamidoamine (PAMAM) dendrimer (G4-OH)-based nanomedicines can be delivered to the fetus by intra-amniotic administration, in a mouse model of intrauterine inflammation. The time-dependent accumulation of G4-OH-fluorophore conjugate was quantified by fluorescence. These studies suggest that, after intra-amniotic administration, there is significant accumulation of dendrimer in the fetus gut and brain. In addition, there is some fetal-maternal transport of the dendrimer. Confocal microscopy confirmed the presence of G4-OH in the fetal brain, with a large accumulation in the brain blood vessels and the brain parenchyma, and some microglial uptake. We believe that intra-amniotic administration of G4-OH-drug nanomedicines may enable the treatment of diseases related to intrauterine inflammation and fetal neuroinflammation. Using a mouse model of intrauterin inflammation leading to neuroinflammation in the fetus, these investigators demonstrate that intra-amniotic delivery of hydroxyl polyamidoamine (PAMAM) dendrimer (G4-OH)-based nanomedicines may provide an effective method in preventing this complication. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Microenvironment-Mediated Mechanisms of Resistance to HER2 Inhibitors Differ between HER2+ Breast Cancer Subtypes.

    Science.gov (United States)

    Watson, Spencer S; Dane, Mark; Chin, Koei; Tatarova, Zuzana; Liu, Moqing; Liby, Tiera; Thompson, Wallace; Smith, Rebecca; Nederlof, Michel; Bucher, Elmar; Kilburn, David; Whitman, Matthew; Sudar, Damir; Mills, Gordon B; Heiser, Laura M; Jonas, Oliver; Gray, Joe W; Korkola, James E

    2018-03-28

    Extrinsic signals are implicated in breast cancer resistance to HER2-targeted tyrosine kinase inhibitors (TKIs). To examine how microenvironmental signals influence resistance, we monitored TKI-treated breast cancer cell lines grown on microenvironment microarrays composed of printed extracellular matrix proteins supplemented with soluble proteins. We tested ∼2,500 combinations of 56 soluble and 46 matrix microenvironmental proteins on basal-like HER2+ (HER2E) or luminal-like HER2+ (L-HER2+) cells treated with the TKIs lapatinib or neratinib. In HER2E cells, hepatocyte growth factor, a ligand for MET, induced resistance that could be reversed with crizotinib, an inhibitor of MET. In L-HER2+ cells, neuregulin1-β1 (NRG1β), a ligand for HER3, induced resistance that could be reversed with pertuzumab, an inhibitor of HER2-HER3 heterodimerization. The subtype-specific responses were also observed in 3D cultures and murine xenografts. These results, along with bioinformatic pathway analysis and siRNA knockdown experiments, suggest different mechanisms of resistance specific to each HER2+ subtype: MET signaling for HER2E and HER2-HER3 heterodimerization for L-HER2+ cells. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Thin film properties of triphenylamine-cored dendrimers: A molecular approach to control aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Vamvounis, George, E-mail: g.vamvounis@uq.edu.au; Pivrikas, Almantas; Shaw, Paul E.; Burn, Paul L.

    2013-12-02

    The solid-state photophysical and charge transport properties of two first-generation dendrimers are presented. The dendrimers are comprised of a triphenylamine core, dendrons containing a phenyl branching unit with thiophene (Dendrimer 1) or bithiophene (Dendrimer 2) moieties, and dodecyl surface groups. For Dendrimer 1, the excited state is located within the center of the dendrimer giving rise to a moderate solid-state photoluminescence quantum yield (Φ{sub pl}) (0.13) and significant charge trapping, with both observations due to the degree of overlap of the main electroactive chromophores on adjacent dendrimers. For Dendrimer 2, the excited state is located within the dendron and in the solid-state this leads to a strongly red-shifted and weakened emission (Φ{sub pl} ∼ 0.02) due to strong intermolecular chromophore interactions. For films of Dendrimer 2 the charge mobility was higher than Dendrimer 1 but was still limited by a low density of strongly interacting electroactive chromophores. The pronounced difference between the solid-state properties of the two dendrimers is simply engineered by the addition of an extra thiophene in each of the dendrons. - Highlights: • Photophysical and charge-transport properties of two dendrimers are investigated. • Excited-state is on the center for Dendrimer 1 and on the dendron for Dendrimer 2. • Film quantum yield of luminescence is higher for Dendrimer 1. • Dendrimer 1 displays greater charge trapping at high fields.

  14. Novel anti-Sialyl-Tn monoclonal antibodies and antibody-drug conjugates demonstrate tumor specificity and anti-tumor activity.

    Science.gov (United States)

    Prendergast, Jillian M; Galvao da Silva, Ana Paula; Eavarone, David A; Ghaderi, Darius; Zhang, Mai; Brady, Dane; Wicks, Joan; DeSander, Julie; Behrens, Jeff; Rueda, Bo R

    Targeted therapeutics that can differentiate between normal and malignant tumor cells represent the ideal standard for the development of a successful anti-cancer strategy. The Sialyl-Thomsen-nouveau antigen (STn or Sialyl-Tn, also known as CD175s) is rarely seen in normal adult tissues, but it is abundantly expressed in many types of human epithelial cancers. We have identified novel antibodies that specifically target with high affinity the STn glycan independent of its carrier protein, affording the potential to recognize a wider array of cancer-specific sialylated proteins. A panel of murine monoclonal anti-STn therapeutic antibodies were generated and their binding specificity and efficacy were characterized in vitro and in in vivo murine cancer models. A subset of these antibodies were conjugated to monomethyl auristatin E (MMAE) to generate antibody-drug conjugates (ADCs). These ADCs demonstrated in vitro efficacy in STn-expressing cell lines and significant tumor growth inhibition in STn-expressing tumor xenograft cancer models with no evidence of overt toxicity.

  15. Selective anti-proliferation of HER2-positive breast cancer cells by anthocyanins identified by high-throughput screening.

    Directory of Open Access Journals (Sweden)

    Weihua Liu

    Full Text Available Overexpressed Human epidermal growth factor receptor 2 (HER2 drives the biology of 20% breast cancer and is a prediction of a poor prognosis for patients. HER2-targeted therapies significantly improve outcomes for HER2-positive patients. Traditional Chinese herbs/medicines have been used to treat breast cancer patients including HER2-positive patients in Asia for decades. Although the traditional medicines demonstrate efficacy in clinics for HER2-positive patients, the mechanism is largely unknown. In this article, we screened a 10,000 natural product library in 6 different cell lines representing breast cancer, and assessed the ability of each drug to cause cytotoxicity through a high-throughput screening approach. We have identified eight natural compounds that selectively inhibit the proliferation of HER2-positive cells. Two of the hit compounds, peonidin-3-glucoside and cyaniding-3-glucoside, are both extracts from black rice. They inhibit the phospho-HER2 and phospho-AKT and were confirmed to induce HER2-psotive breast cancer cells apoptosis both in vitro and in vivo. Peonidin-3-glucoside and cyaniding-3-glucoside treatments significantly reduced the tumor size and volume in vivo compared to the control group. There is no significant difference of antitumorgenic effects between peonidin-3-glucoside and cyaniding-3-glucoside treatments.

  16. Quantum-Dot-Based Theranostic Micelles Conjugated with an Anti-EGFR Nanobody for Triple-Negative Breast Cancer Therapy.

    Science.gov (United States)

    Wang, Yuyuan; Wang, Yidan; Chen, Guojun; Li, Yitong; Xu, Wei; Gong, Shaoqin

    2017-09-13

    A quantum-dot (QD)-based micelle conjugated with an anti-epidermal growth factor receptor (EGFR) nanobody (Nb) and loaded with an anticancer drug, aminoflavone (AF), has been engineered for EGFR-overexpressing cancer theranostics. The near-infrared (NIR) fluorescence of the indium phosphate core/zinc sulfide shell QDs (InP/ZnS QDs) allowed for in vivo nanoparticle biodistribution studies. The anti-EGFR nanobody 7D12 conjugation improved the cellular uptake and cytotoxicity of the QD-based micelles in EGFR-overexpressing MDA-MB-468 triple-negative breast cancer (TNBC) cells. In comparison with the AF-encapsulated nontargeted (i.e., without Nb conjugation) micelles, the AF-encapsulated Nb-conjugated (i.e., targeted) micelles accumulated in tumors at higher concentrations, leading to more effective tumor regression in an orthotopic triple-negative breast cancer xenograft mouse model. Furthermore, there was no systemic toxicity observed with the treatments. Thus, this QD-based Nb-conjugated micelle may serve as an effective theranostic nanoplatform for EGFR-overexpressing cancers such as TNBCs.

  17. Anti-VEGF antibody conjugated CdHgTe quantum dots as a fluorescent probe for imaging in living mouse

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Lili; Cui, Hongjing [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing (China); Liu, Yu [Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing (China); Zhong, Wenying, E-mail: wyzhong@cpu.edu.cn [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing (China); Key laboratory of Biomedical Functional Materials, China Pharmaceutical University, Nanjing (China)

    2016-05-15

    The dual-function anti-VEGF antibody conjugated CdHgTe quantum dots with good targeting property was successfully prepared. In this system, anti-VEGF antibody is not only a target agent but also a therapeutic drug. The anti-VEGF antibody conjugated near-infrared quantum dots can achieve the purposes of detection and treatment at the same time. As-prepared dual-function fluorescent probe in this work has been successfully applied for in vivo and in vitro imaging, which is promising in rapid tumor detection.

  18. Tyrosine kinase inhibitors for brain metastases in HER2-positive breast cancer.

    Science.gov (United States)

    Duchnowska, Renata; Loibl, Sibylle; Jassem, Jacek

    2018-06-01

    Approximately 30-50% of advanced HER2-positive breast cancer patients will develop central nervous system (CNS) metastases, with an annual risk of around 10%, and a half of them will die from brain progression. An increased risk of brain metastases is also seen in patients with early HER2-positive breast cancer administered curative therapy. Brain metastases in HER2-positive breast cancer patients usually constitute the first site of recurrence. The administration of anti-HER2 monoclonal antibodies, trastuzumab and pertuzumab, considerably delays the onset of symptomatic brain disease: however, the limited penetration of these compounds into the CNS hinders their efficacy. The small-molecule tyrosine kinase inhibitors of epidermal growth factor receptors family have established activity in HER2-positive breast cancer in both advanced disease and neoadjuvant setting. Favorable physico-chemical properties of these compounds allow them for a more efficient penetration through the blood-brain barrier, and hold the promise for more effective prevention and treatment of brain metastases. In this article we review the role of currently available or investigational HER2 tyrosine kinase inhibitors: lapatinib, neratinib, afatinib and tucatinib in the treatment of brain metastases in HER2-positive breast cancer patients. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. [HER2 gene amplification assay: is CISH an alternative to FISH?].

    Science.gov (United States)

    Denoux, Yves; Arnould, Laurent; Fiche, Maryse; Lannes, B; Couturier, Jérôme; Vincent-Salomon, Anne; Penault-Llorca, Frédérique; Antoine, M; Balaton, A; Baranzelli, M C; Becette, V; Bellocq, J P; Bibeau, F; Ettore, F; Fridman, V; Gnassia, J P; Jacquemier, J; MacGrogan, G; Mathieu, M C; Migeon, C; Rigaud, C; Roger, P; Sigal-Zafrani, B; Simony-Lafontaine, J; Trassard, M; Treilleux, I; Verriele, V; Voigt, J J

    2003-12-01

    The HER2 proto-oncogene encodes a transmembrane protein, which is considered to function as a growth factor receptor. Overexpression of this protein found by immunohistochemistry in about 20% of infiltrating breast carcinomas, has a predictive value of response to treatment by trastuzumab, an anti-HER2 humanized monoclonal antibody. Search for HER2 gene amplification is necessary to adapt the immunohistochemical technique quality and also in the cases of delicate analysis or weak overexpression. It is usually carried out by Fluorescence In Situ Hybridization (FISH). A more recent hybridization technique, named CISH because of its chromogenic revelation is an alternative method, which gives highly correlated results with FISH. We present details of this technique, which may be more familiar for the pathologists than FISH, because reading analysis is similar to that of immunohistochemical staining.

  20. Native mass spectrometry and ion mobility characterization of trastuzumab emtansine, a lysine-linked antibody drug conjugate.

    Science.gov (United States)

    Marcoux, Julien; Champion, Thierry; Colas, Olivier; Wagner-Rousset, Elsa; Corvaïa, Nathalie; Van Dorsselaer, Alain; Beck, Alain; Cianférani, Sarah

    2015-08-01

    Antibody-drug conjugates (ADCs) are biochemotherapeutics consisting of a cytotoxic chemical drug linked covalently to a monoclonal antibody. Two main classes of ADCs, namely cysteine and lysine conjugates, are currently available on the market or involved in clinical trials. The complex structure and heterogeneity of ADCs makes their biophysical characterization challenging. For cysteine conjugates, hydrophobic interaction chromatography is the gold standard technique for studying drug distribution, the naked antibody content, and the average drug to antibody ratio (DAR). For lysine ADC conjugates on the other hand, which are not amenable to hydrophobic interaction chromatography because of their higher heterogeneity, denaturing mass spectrometry (MS) and UV/Vis spectroscopy are the most powerful approaches. We report here the use of native MS and ion mobility (IM-MS) for the characterization of trastuzumab emtansine (T-DM1, Kadcyla(®)). This lysine conjugate is currently being considered for the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and combines the anti-HER2 antibody trastuzumab (Herceptin(®)), with the cytotoxic microtubule-inhibiting maytansine derivative, DM1. We show that native MS combined with high-resolution measurements and/or charge reduction is beneficial in terms of the accurate values it provides of the average DAR and the drug load profiles. The use of spectral deconvolution is discussed in detail. We report furthermore the use of native IM-MS to directly determine DAR distribution profiles and average DAR values, as well as a molecular modeling investigation of positional isomers in T-DM1. © 2015 The Protein Society.

  1. Dendrimers bind antioxidant polyphenols and cisplatin drug.

    Directory of Open Access Journals (Sweden)

    Amine Abderrezak

    Full Text Available Synthetic polymers of a specific shape and size play major role in drug delivery systems. Dendrimers are unique synthetic macromolecules of nanometer dimensions with a highly branched structure and globular shape with potential applications in gene and drug delivery. We examine the interaction of several dendrimers of different compositions mPEG-PAMAM (G3, mPEG-PAMAM (G4 and PAMAM (G4 with hydrophilic and hydrophobic drugs cisplatin, resveratrol, genistein and curcumin at physiological conditions. FTIR and UV-visible spectroscopic methods as well as molecular modeling were used to analyse drug binding mode, the binding constant and the effects of drug complexation on dendrimer stability and conformation. Structural analysis showed that cisplatin binds dendrimers in hydrophilic mode via Pt cation and polymer terminal NH(2 groups, while curcumin, genistein and resveratrol are located mainly in the cavities binding through both hydrophobic and hydrophilic contacts. The overall binding constants of durg-dendrimers are ranging from 10(2 M(-1 to 10(3 M(-1. The affinity of dendrimer binding was PAMAM-G4>mPEG-PAMAM-G4>mPEG-PAMAM-G3, while the order of drug-polymer stability was curcumin>cisplatin>genistein>resveratrol. Molecular modeling showed larger stability for genisten-PAMAM-G4 (ΔG = -4.75 kcal/mol than curcumin-PAMAM-G4 ((ΔG = -4.53 kcal/mol and resveratrol-PAMAM-G4 ((ΔG = -4.39 kcal/mol. Dendrimers might act as carriers to transport hydrophobic and hydrophilic drugs.

  2. Charge transport in highly efficient iridium cored electrophosphorescent dendrimers

    Science.gov (United States)

    Markham, Jonathan P. J.; Samuel, Ifor D. W.; Lo, Shih-Chun; Burn, Paul L.; Weiter, Martin; Bässler, Heinz

    2004-01-01

    Electrophosphorescent dendrimers are promising materials for highly efficient light-emitting diodes. They consist of a phosphorescent core onto which dendritic groups are attached. Here, we present an investigation into the optical and electronic properties of highly efficient phosphorescent dendrimers. The effect of dendrimer structure on charge transport and optical properties is studied using temperature-dependent charge-generation-layer time-of-flight measurements and current voltage (I-V) analysis. A model is used to explain trends seen in the I-V characteristics. We demonstrate that fine tuning the mobility by chemical structure is possible in these dendrimers and show that this can lead to highly efficient bilayer dendrimer light-emitting diodes with neat emissive layers. Power efficiencies of 20 lm/W were measured for devices containing a second-generation (G2) Ir(ppy)3 dendrimer with a 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene electron transport layer.

  3. A novel theranostic nanobioconjugate. "1"2"5/"1"3"1I labeled phenylalanine conjugated boron nitride nanotubes

    International Nuclear Information System (INIS)

    Ozge Kozgus Guldu; Perihan Unak; Suna Timur

    2017-01-01

    Here we report the synthesis of boron nitride nanotubes (BNNTs) via a chemical vapor deposition method, as potential agents for boron neutron capture therapy. BNNTs were functionalized with PAMAM[G-2] dendrimer and then, conjugated with l-Phe using EDC/NHS. After that, BNNTs were radiolabeled with "1"2"5/"1"3"1I, which are commonly used for both therapy and diagnosis in clinical and pre-clinical studies. BNNTs were radiolabeled with a maximum yield with "1"2"5/"1"3"1I in compared with 4-borono-l-phenyalanine which is currently used as a commercial drug. Radiolabeling parameters were optimized with thin layer radiochromatography and high performance liquid radiochromatography. BNNTs are promising nanobioconjugates as new theranostic agents. (author)

  4. A novel dendritic cell-based immunization approach for the induction of durable Th1-polarized anti-HER-2/neu responses in women with early breast cancer

    Science.gov (United States)

    Koski, Gary K.; Koldovsky, Ursula; Xu, Shuwen; Mick, Rosemarie; Sharma, Anupama; Fitzpatrick, Elizabeth; Weinstein, Susan; Nisenbaum, Harvey; Levine, Bruce L; Fox, Kevin; Zhang, Paul; Czerniecki, Brian J

    2011-01-01

    Twenty-seven subjects with HER-2/neu over-expressing ductal carcinoma in situ of the breast were enrolled in a neoadjuvant immunization trial for safety and immunogenicity of DC1-polarized dendritic cells (DC1) pulsed with six HER-2/neu promiscuous MHC class II-binding peptides, plus two additional HLA-A2.1 class I-binding peptides. DC1 were generated with IFN-γ plus a special clinical-grade bacterial endotoxin (LPS) and administered directly into groin lymph nodes four times at weekly intervals prior to scheduled surgical resection of DCIS. Subjects were monitored for the induction of new or enhanced anti-peptide reactivity by IFN-γ ELIspot and ELISA assays performed on Th cells obtained from peripheral blood or excised sentinel lymph nodes. Responses by CTL against HLA-A2.1-binding peptides were measured using peptide-pulsed T2 target cells or HER-2/neu-expressing or non-expressing tumor cell lines. DC1 showed surface phenotype indistinct from “gold standard” inflammatory cocktail-activated DC, but displayed a number of distinguishing functional characteristics including the secretion of soluble factors and enhanced “killer DC” capacity against tumor cells in vitro. Post-immunization, we observed sensitization of Th cells to at least 1 class II peptide in 22 of 25 (88%, 95% exact CI 68.8 – 97.5%) evaluable subjects, while eleven of 13 (84.6%, 95% exact CI 64 – 99.8%) HLA-A2.1 subjects were successfully sensitized to class I peptides. Perhaps most importantly, anti-HER-2/neu peptide responses were observed up to 52 months post-immunization. These data show even in the presence of early breast cancer such DC1 are potent inducers of durable type I-polarized immunity, suggesting potential clinical value for development of cancer immunotherapy. PMID:22130160

  5. Limiting the protein corona: A successful strategy for in vivo active targeting of anti-HER2 nanobody-functionalized nanostars.

    Science.gov (United States)

    D'Hollander, Antoine; Jans, Hilde; Velde, Greetje Vande; Verstraete, Charlotte; Massa, Sam; Devoogdt, Nick; Stakenborg, Tim; Muyldermans, Serge; Lagae, Liesbet; Himmelreich, Uwe

    2017-04-01

    Gold nanoparticles hold great promise as anti-cancer theranostic agents against cancer by actively targeting the tumor cells. As this potential has been supported numerously during in vitro experiments, the effective application is hampered by our limited understanding and control of the interactions within complex in vivo biological systems. When these nanoparticles are exposed to a biological environment, their surfaces become covered with proteins and biomolecules, referred to as the protein corona, reducing the active targeting capabilities. We demonstrate a chemical strategy to overcome this issue by reducing the protein corona's thickness by blocking the active groups of the self-assembled monolayer on gold nanostars. An optimal blocking agent, 2-mercapto ethanol, has been selected based on charge and length of the carbon chain. By using a nanobody as a biological ligand of the human epidermal growth factor 2 receptor (HER2), the active targeting is demonstrated in vitro and in vivo in an experimental tumor model by using darkfield microscopy and photoacoustic imaging. In this study, we have established gold nanostars as a conceivable theranostic agent with a specificity for HER2-positive tumors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Transfer of PAMAM dendrimers across human placenta: prospects of its use as drug carrier during pregnancy.

    Science.gov (United States)

    Menjoge, Anupa R; Rinderknecht, Amber L; Navath, Raghavendra S; Faridnia, Masoud; Kim, Chong J; Romero, Roberto; Miller, Richard K; Kannan, Rangaramanujam M

    2011-03-30

    Dendrimers offer significant potential as nanocarriers for targeted delivery of drugs and imaging agents. The objectives of this study were to evaluate the transplacental transport, kinetics and biodistribution of PAMAM dendrimers ex-vivo across the human placenta in comparison with antipyrine, a freely diffusible molecule, using dually perfused re-circulating term human placental lobules. The purpose of this study is to determine if dendrimers as drug carriers can be used to design drug delivery systems directed at selectively treating either the mother or the fetus. The transplacental transfers of fluorescently (Alexa 488) tagged PAMAM dendrimer (16 kDa) and antipyrine (188 Da) from maternal to fetal circulation were measured using HPLC/dual UV and fluorescent detector (sensitivity of 10 ng/mL for dendrimer and 100 ng/mL for antipyrine respectively). C(max) for the dendrimer-Alexa (DA) in maternal perfusate (T(max)=15 min) was 18 times higher than in the fetal perfusate and never equilibrated with the maternal perfusate during 5.5 h of perfusion (n=4). DA exhibited a measurable but low transplacental transport of 2.26±0.12 μg/mL during 5.5h, where the mean transplacental transfer was 0.84±0.11% of the total maternal concentration and the feto-maternal ratio as percent was 0.073%±0.02. The biochemical and physiological analysis of the placentae perfused with DA demonstrated normal function throughout the perfusion. The immunofluorescence histochemistry confirmed that the biodistribution of DA in perfused placenta was sparsely dispersed, and when noted was principally seen in the inter-villous spaces and outer rim of the villous branches. In a few cases, DA was found internalized and localized in nuclei and cytoplasm of syncytiotrophoblast and inside the villous core; however, DA was mostly absent from the villous capillaries. In conclusion, the PAMAM dendrimers exhibited a low rate of transfer from maternal to the fetal side across the perfused human placenta

  7. Studying the Polypropylenimine-G2 (PPI-G2 Dendrimer Performance in Removal of Escherichia coli, Proteus mirabilis, Bacillus subtilis and Staphylococcus aureus from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Hasan Izanloo

    2015-09-01

    Full Text Available Abstract Background: Dendrimers are a subset of branched structures that have certain structural order. The aim of this study was to investigate the performance of Polypropylenimine-G2 (PPI-G2 dendrimers in removal of Escherichia coli, Proteus mirabilis, Bacillus subtilis and Staphylococcus aureus from aqueous solution. Materials and Methods: In this experimental study, initially dilution of 103 CFU/ml was prepared from each strain of bacteria. Then, different concentrations of dendrimers (0.5, 5, 50 and 500 µg/ml was added to water. In order to determine the efficiency of dendrimers in removal of bacteria, samples were taken at different times (0, 10, 20, 30, 40, 50 and 60 min and were cultured on nutrient agar medium. Samples were incubated for 24 hours at 37 ° C and then the number of colonies was counted. Results: By the increasment of dendrimer concentration and contact time, the number of bacteria in aqueous solution decreased. In times of 40, 50 and 60 minutes, and the concentrations of 50 and 500 µg/ml, all kinds of bacteria in aqueous solution were removed. 0.5 µg/ml of dendrimer concentration had not effect in reducing the number of Escherichia coli and Proteus mirabilis. The effect of dendrimer on gram-negative bacteria was weaker than gram-positive bacteria. Conclusion: Results of this study indicated that PPI-G2 dendrimer is able to remove Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Bacillus subtilis in aqueous solution. However, using dendrimers can be considered as a new approach for drinking water disinfection but it requires further wide range studies.

  8. Fluorescence polarization measures energy funneling in single light-harvesting antennas—LH2 vs conjugated polymers

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J.; Sforazzini, Giuseppe; Anderson, Harry L.; Pullerits, Tõnu; Scheblykin, Ivan G.

    2015-10-01

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ɛ). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ɛ = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  9. Invertase-labeling gold-dendrimer for in situ amplified detection mercury(II) with glucometer readout and thymine-Hg(2+)-thymine coordination chemistry.

    Science.gov (United States)

    Qiu, Zhenli; Shu, Jian; Jin, Guixiao; Xu, Mingdi; Wei, Qiaohua; Chen, Guonan; Tang, Dianping

    2016-03-15

    A simple, low-cost transducer with glucometer readout was designed for sensitive detection of mercury(II) (Hg(2+)), coupling with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and invertase-functionalized gold-dendrimer nanospheres for the signal amplification. Initially, nanogold-encapsulated poly(amidoamine) dendrimers (Au DENs) were synthesized by in-situ reduction of gold(III). Thereafter, the as-prepared Au DENs were utilized for the labeling of invertase and T-rich signal DNA probe. In the presence of target Hg(2+), the functionalized Au DENs were conjugated to capture DNA probe-modified electrode via T-Hg(2+)-T coordination chemistry. Accompanying the Au DENs, the labeled invertase could hydrolyze sucrose into glucose, which could be quantitatively monitored by an external personal glucometer (PGM). The PGM signal increased with the increasing target Hg(2+) in the sample. Under the optimal conditions, our designed sensing platform exhibited good PGM responses toward target Hg(2+), and allowed the detection of Hg(2+) at a concentration as low as 4.2 pM. This sensing system also displayed remarkable specificity relative to target Hg(2+) against other competing ions, and could be applied for reliable monitoring of spiked Hg(2+) into the environmental water samples with satisfactory results. With the advantages of cost-effectiveness, simplicity, portability, and convenience, our strategy provides a tremendous potential to be a promising candidate for point-of-use monitoring of non-glucose targets by the public. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Tailoring DNA vaccines: designing strategies against HER2 positive cancers

    Directory of Open Access Journals (Sweden)

    Cristina eMarchini

    2013-05-01

    Full Text Available The crucial role of HER2 in epithelial transformation and its selective overexpression on cancer tissues makes it an ideal target for cancer immunotherapies such as passive immunotherapy with Trastuzumab. There are, however, a number of concerns regarding the use of monoclonal antibodies which include resistance, repeated treatments, considerable costs and side effects that make active immunotherapies against HER2 desirable alternative approaches. The efficacy of anti-HER2 DNA vaccination has been widely demonstrated in transgenic cancer-prone mice, which recapitulate several features of human breast cancers. Nonetheless, the rational design of a cancer vaccine able to trigger a long lasting immunity, and thus prevent tumor recurrence in patients, would require the understanding of how tolerance and immunosuppression regulate antitumor immune responses and, at the same time, the identification of the most immunogenic portions of the target protein. We herein retrace the findings that led to our most promising DNA vaccines that, by encoding human/rat chimeric forms of HER2, are able to circumvent peripheral tolerance. Preclinical data obtained with these chimeric DNA vaccines have provided the rationale for their use in an ongoing phase I clinical trial (EudraCT 2011-001104-34.

  11. Durable Clinical Benefit of Pertuzumab in a Young Patient with BRCA2 Mutation and HER2-Overexpressing Breast Cancer Involving the Brain

    Directory of Open Access Journals (Sweden)

    Anna Koumarianou

    2016-01-01

    Full Text Available Patients with HER2-positive breast cancer and brain metastases have limited treatment options, and, as a result of their poor performance status and worse prognosis, they are underrepresented in clinical trials. Not surprisingly, these patients may not be fit enough to receive any active treatment and are offered supportive therapy. BRCA2 mutations are reported to be rarely associated with HER2-overexpressing advanced breast cancer and even more rarely with brain metastases at diagnosis. We report on a BRCA2-positive breast cancer patient with metastatic disease in multiple sites, including the brain, and poor performance status who exhibited an extraordinary clinical and imaging response to the novel anti-HER2 therapy pertuzumab after multiple lines of therapy including anti-HER2 targeting. To our knowledge, the clinicopathologic and therapeutic characteristics of this patient point to a unique case and an urgent need for further investigation of pertuzumab in patients with brain metastases.

  12. Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

    International Nuclear Information System (INIS)

    Kemp, Melissa M; Linhardt, Robert J; Kumar, Ashavani; Ajayan, Pulickel; Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A

    2009-01-01

    Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

  13. Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Melissa M; Linhardt, Robert J [Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Kumar, Ashavani; Ajayan, Pulickel [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A, E-mail: Shaker.mousa@acphs.ed [Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Albany, NY 12208 (United States)

    2009-11-11

    Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

  14. Radiation binary targeted therapy for HER-2 positive breast cancers: assumptions, theoretical assessment and future directions

    Energy Technology Data Exchange (ETDEWEB)

    Mundy, Daniel W [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47909 (United States); Harb, Wael [Horizon Oncology, The Care Group, Unity Medical Center, Lafayette, IN 47901 (United States); Jevremovic, Tatjana [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47909 (United States)

    2006-03-21

    A novel radiation targeted therapy is investigated for HER-2 positive breast cancers. The proposed concept combines two known approaches, but never used together for the treatment of advanced, relapsed or metastasized HER-2 positive breast cancers. The proposed radiation binary targeted concept is based on the anti HER-2 monoclonal antibodies (MABs) that would be used as vehicles to transport the nontoxic agent to cancer cells. The anti HER-2 MABs have been successful in targeting HER-2 positive breast cancers with high affinity. The proposed concept would utilize a neutral nontoxic boron-10 predicting that anti HER-2 MABs would assure its selective delivery to cancer cells. MABs against HER-2 have been a widely researched strategy in the clinical setting. The most promising antibody is Trastuzumab (Herceptin (registered) ). Targeting HER-2 with the MAB Trastuzumab has been proven to be a successful strategy in inducing tumour regression and improving patient survival. Unfortunately, these tumours become resistant and afflicted women succumb to breast cancer. In the proposed concept, when the tumour region is loaded with boron-10 it is irradiated with neutrons (treatment used for head and neck cancers, melanoma and glioblastoma for over 40 years in Japan and Europe). The irradiation process takes less than an hour producing minimal side effects. This paper summarizes our recent theoretical assessments of radiation binary targeted therapy for HER-2 positive breast cancers on: the effective drug delivery mechanism, the numerical model to evaluate the targeted radiation delivery and the survey study to find the neutron facility in the world that might be capable of producing the radiation effect as needed. A novel method of drug delivery utilizing Trastuzumab is described, followed by the description of a computational Monte Carlo based breast model used to determine radiation dose distributions. The total flux and neutron energy spectra of five currently available

  15. Cationic PAMAM dendrimers as pore-blocking binary toxin inhibitors.

    Science.gov (United States)

    Förstner, Philip; Bayer, Fabienne; Kalu, Nnanya; Felsen, Susanne; Förtsch, Christina; Aloufi, Abrar; Ng, David Y W; Weil, Tanja; Nestorovich, Ekaterina M; Barth, Holger

    2014-07-14

    Dendrimers are unique highly branched macromolecules with numerous groundbreaking biomedical applications under development. Here we identified poly(amido amine) (PAMAM) dendrimers as novel blockers for the pore-forming B components of the binary anthrax toxin (PA63) and Clostridium botulinum C2 toxin (C2IIa). These pores are essential for delivery of the enzymatic A components of the internalized toxins from endosomes into the cytosol of target cells. We demonstrate that at low μM concentrations cationic PAMAM dendrimers block PA63 and C2IIa to inhibit channel-mediated transport of the A components, thereby protecting HeLa and Vero cells from intoxication. By channel reconstitution and high-resolution current recording, we show that the PAMAM dendrimers obstruct transmembrane PA63 and C2IIa pores in planar lipid bilayers at nM concentrations. These findings suggest a new potential role for the PAMAM dendrimers as effective polyvalent channel-blocking inhibitors, which can protect human target cells from intoxication with binary toxins from pathogenic bacteria.

  16. Low cytotoxicity fluorescent PAMAM dendrimer as gene carriers for monitoring the delivery of siRNA

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Lingmei [Sichuan University, State Key Laboratory of Bio-resources and Eco-environment, The Ministry of Education, College of Life Sciences (China); Huang, Saipeng [Chinese Academy of Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry (China); Chen, Zhao [Xi’an Jiaotong University, School of Science (China); Li, Yanchao [Chinese Academy of Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry (China); Liu, Ke [Sichuan University, State Key Laboratory of Bio-resources and Eco-environment, The Ministry of Education, College of Life Sciences (China); Liu, Yang, E-mail: yliu@iccas.ac.cn; Du, Libo, E-mail: dulibo@iccas.ac.cn [Chinese Academy of Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry (China)

    2015-09-15

    Visual detection of gene vectors has attracted a great deal of attention due to the application of these vectors in monitoring and evaluating the effect of gene carriers in living cells. A non-viral vector, the fluorescent PAMAM dendrimer (F-PAMAM), was synthesized through conjugation of PAMAM dendrimers and fluorescein. In vitro and ex vivo experiments show that F-PAMAM exhibits superphotostability, low cytotoxicity and facilitates endocytosis by A549 cells. The vector has a high siRNA binding affinity and it increases the efficiency of cy5-siRNA delivery in A549 cells, in comparison with a cy5-siRNA monomer. Our results provide a new method for simultaneously monitoring the delivery of siRNA and its non-viral carriers in living cells.

  17. Study of Dendrimers by Topological Indices

    Directory of Open Access Journals (Sweden)

    Soleimani Najmeh

    2017-12-01

    Full Text Available In this paper, five degree based topological indices, the first Zagreb (M1, second Zagreb (M2, first multiple Zagreb (PM1, second multiple Zagreb (PM2, and the hyper Zagreb (HM indices of two types of dendrimers are studied. In addition, two distance based topological indices, the total eccentricity (θ and eccentric connectivity (ξc indices of these dendrimers are computed.

  18. Practical computational toolkits for dendrimers and dendrons structure design

    Science.gov (United States)

    Martinho, Nuno; Silva, Liana C.; Florindo, Helena F.; Brocchini, Steve; Barata, Teresa; Zloh, Mire

    2017-09-01

    Dendrimers and dendrons offer an excellent platform for developing novel drug delivery systems and medicines. The rational design and further development of these repetitively branched systems are restricted by difficulties in scalable synthesis and structural determination, which can be overcome by judicious use of molecular modelling and molecular simulations. A major difficulty to utilise in silico studies to design dendrimers lies in the laborious generation of their structures. Current modelling tools utilise automated assembly of simpler dendrimers or the inefficient manual assembly of monomer precursors to generate more complicated dendrimer structures. Herein we describe two novel graphical user interface toolkits written in Python that provide an improved degree of automation for rapid assembly of dendrimers and generation of their 2D and 3D structures. Our first toolkit uses the RDkit library, SMILES nomenclature of monomers and SMARTS reaction nomenclature to generate SMILES and mol files of dendrimers without 3D coordinates. These files are used for simple graphical representations and storing their structures in databases. The second toolkit assembles complex topology dendrimers from monomers to construct 3D dendrimer structures to be used as starting points for simulation using existing and widely available software and force fields. Both tools were validated for ease-of-use to prototype dendrimer structure and the second toolkit was especially relevant for dendrimers of high complexity and size.

  19. DNA assisted self-assembly of PAMAM dendrimers.

    Science.gov (United States)

    Mandal, Taraknath; Kumar, Mattaparthi Venkata Satish; Maiti, Prabal K

    2014-10-09

    We report DNA assisted self-assembly of polyamidoamine (PAMAM) dendrimers using all atom Molecular Dynamics (MD) simulations and present a molecular level picture of a DNA-linked PAMAM dendrimer nanocluster, which was first experimentally reported by Choi et al. (Nano Lett., 2004, 4, 391-397). We have used single stranded DNA (ssDNA) to direct the self-assembly process. To explore the effect of pH on this mechanism, we have used both the protonated (low pH) and nonprotonated (high pH) dendrimers. In all cases studied here, we observe that the DNA strand on one dendrimer unit drives self-assembly as it binds to the complementary DNA strand present on the other dendrimer unit, leading to the formation of a DNA-linked dendrimer dimeric complex. However, this binding process strongly depends on the charge of the dendrimer and length of the ssDNA. We observe that the complex with a nonprotonated dendrimer can maintain a DNA length dependent inter-dendrimer distance. In contrast, for complexes with a protonated dendrimer, the inter-dendrimer distance is independent of the DNA length. We attribute this observation to the electrostatic complexation of a negatively charged DNA strand with the positively charged protonated dendrimer.

  20. Comparison between anti-CEA and anti-HER2 212Pb-labeled mAbs during α-RIT of small volume peritoneal carcinomatosis - Role of activity distribution on therapeutic efficacy and toxicity?

    International Nuclear Information System (INIS)

    Elgqvist, J.; Boudousq, V.; Bobyk, L.; Busson, M.; Lozza, C.; Navarro-Teulon, I.; Pouget, J.P.; Maquaire, P.; Torgue, J.

    2015-01-01

    Full text of publication follows. Objectives: we investigated the role of internalizing/non-internalizing monoclonal antibodies (mAbs) on the final outcome (efficacy/toxicity) of mice treated with alpha radioimmunotherapy (α- RIT) using 212 Pb-labeled mAbs. The relationship between distribution of radioactivity at the tissue level and biological parameters was also assessed. Methods: nude mice bearing 2-3 mm peritoneal nodules obtained by xenograft of A-431 tumor cells, expressing low and high level of HER2 and CEA receptors, respectively, were intraperitoneally (i.p.) injected with increasing activities (370-1480 kBq; 37 MBq/mg) of either 35A7 (non-internalising anti-CEA), Trastuzumab (internalizing anti-HER2) or PX (non-specific) 212 Pb-labeled mAbs. Control groups were injected with corresponding amount of unlabeled mAbs or with NaCl. Tumor growth was followed by bioluminescence and median survival (MS) of control and treated mice was determined. 212 Pb-35A7 and 212 Pb-Trastuzumab biodistribution was used to determine the cumulative uptake of radioactivity (UOR) in organs and tumors. Mean absorbed doses were calculated using the MIRD formalism. Haematological, liver and kidney toxicities were also assessed. Distribution of radioactivity at the tissue level was determined by digital micro-autoradiography and the relationship with biological markers of tissue damage was investigated using immunohistochemistry. Results: a mild and transient haematological toxicity in groups treated with the highest amount of activity was observed. MS of the groups treated either with internalizing or non-internalizing 212 Pb-labeled mAbs was significantly improved compared to those treated with non-specific 212 Pb-PX or those only given unlabeled mAbs or just NaCl. MS ranged from 42 days to 94 days using various activity levels of anti-CEA 212 Pb-35A7 while MS was not reached over the follow-up period of 130 days for mice treated with anti-HER2 212 Pb-Trastuzumab. However, UOR and

  1. Comparison of generation 3 polyamidoamine dendrimer and generation 4 polypropylenimine dendrimer on drug loading, complex structure, release behavior, and cytotoxicity

    Science.gov (United States)

    Shao, Naimin; Su, Yunzhang; Hu, Jingjing; Zhang, Jiahai; Zhang, Hongfeng; Cheng, Yiyun

    2011-01-01

    Background Polyamidoamine (PAMAM) and polypropylenimine (PPI) dendrimers are the commercially available and most widely used dendrimers in pharmaceutical sciences and biomedical engineering. In the present study, the loading and release behaviors of generation 3 PAMAM and generation 4 PPI dendrimers with the same amount of surface amine groups (32 per dendrimer) were compared using phenylbutazone as a model drug. Methods The dendrimer-phenylbutazone complexes were characterized by 1H nuclear magnetic resonance and nuclear Overhauser effect techniques, and the cytotoxicity of each dendrimer was evaluated. Results Aqueous solubility results suggest that the generation 3 PAMAM dendrimer has a much higher loading ability towards phenylbutazone in comparison with the generation 4 PPI dendrimer at high phenylbutazone-dendrimer feeding ratios. Drug release was much slower from the generation 3 PAMAM matrix than from the generation 4 PPI dendrimer. In addition, the generation 3 PAMAM dendrimer is at least 50-fold less toxic than generation 4 PPI dendrimer on MCF-7 and A549 cell lines. Conclusion Although the nuclear Overhauser effect nuclear magnetic resonance results reveal that the generation 4 PPI dendrimer with a more hydrophobic interior encapsulates more phenylbutazone, the PPI dendrimer-phenylbutazone inclusion is not stable in aqueous solution, which poses a great challenge during drug development. PMID:22267921

  2. Designing a HER2/neu promoter to drive α1,3galactosyltransferase expression for targeted anti-αGal antibody-mediated tumor cell killing

    International Nuclear Information System (INIS)

    Lanteri, Marion; Ollier, Laurence; Giordanengo, Valérie; Lefebvre, Jean-Claude

    2005-01-01

    Our goal was to specifically render tumor cells susceptible to natural cytolytic anti-αGal antibodies by using a murine α1,3galactosyltransferase (mαGalT) transgene driven by a designed form of HER2/neu promoter (pNeu), the transcription of which is frequently observed to be above basal in breast tumors. Indeed, the αGalT activity that promotes Galα1,3Galβ1,4GlcNAc-R (αGal) epitope expression has been mutationally disrupted during the course of evolution, starting from Old World primates, and this has led to the counter-production of large amounts of cytotoxic anti-αGal antibodies in recent primates, including man. Expression of the endogenous c-erbB-2 gene was investigated in various cell lines by northern blotting. A mαGalT cDNA was constructed into pcDNA3 vector downstream of the original CMV promoter (pCMV/mαGalT) and various forms of pNeu were prepared by PCR amplification and inserted in the pCMV/mαGalT construct upstream of the mαGalT cDNA, in the place of the CMV promoter. These constructs were transferred into HEK-293 control and breast tumor cell lines. Stably transfected cells were analyzed by northern blotting for their expression of αGalT and c-erbB-2, and by flow cytometry for their binding with fluorescein isothiocyanate-conjugated Griffonia simplicifolia/isolectin B4. We show that expression of the mαGalT was up- or down-modulated according to the level of endogenous pNeu activity and the particular form of constructed pNeu. Among several constructs, two particular forms of the promoter, pNeu250 containing the CCAAT box and the PEA3 motif adjacent to the TATAA box, and pNeu664, which has three additional PEA3 motifs upstream of the CCAAT box, were found to promote differential αGalT expression. Our results strengthen current concepts about the crucial role played by the proximal PEA3 motif of pNeu, and may represent a novel therapeutic approach for the development of targeted transgene expression

  3. Effect of deoxycholate conjugation on stability of pDNA/polyamidoamine-diethylentriamine (PAM-DET) polyplex against ionic strength.

    Science.gov (United States)

    Jeong, Yunseong; Jin, Geun-Woo; Choi, Eunjung; Jung, Ji Hyuk; Park, Jong-Sang

    2011-11-28

    Polyplexes formed from cationic polymer/pDNA have been known to be vulnerable to external ionic strength. To improve polyplex stability against ionic strength, we attempted the chemical conjugation of the hydrophobic deoxycholate (DC) moiety to the polyamidoamine-diethylenetriamine (PAM-DET) dendrimer. Dynamic light scattering studies showed that the tolerance of the resulting PAM-DET-DC against ionic strength is higher than that of PAM-DET. In addition, we confirmed that the stability of polyplex has a strong relationship with the degree of conjugation of the DC moiety to the PAM-DET dendrimer and the charge ratio of PAM-DET-DC. Furthermore, the transfection efficiency of the PAM-DET-DC polyplex is higher than that of PAM-DET but its cytotoxicity remains the same. Therefore, the chemical conjugation of DC is a safe and effective method for increasing the stability of supramolecules formed from electrostatic interaction. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Charge transport properties of carbazole dendrimers in organic field-effect transistors

    Science.gov (United States)

    Mutkins, Karyn; Chen, Simon S. Y.; Aljada, Muhsen; Powell, Ben J.; Olsen, Seth; Burn, Paul L.; Meredith, Paul

    2011-10-01

    We report three generations of p-type dendrimer semiconductors comprised of spirobifluorene cores, carbazole branching units and fluorene surface groups for use in organic field-effect transistors (OFETs). The group of dendrimers are defined by their generation and noted as SBF-(Gx)2, where x is the generation. Top contact-bottom gate OFETs were fabricated by spin-coating the dendrimers onto an n-octyltrichlorosilane (OTS) passivated silicon dioxide surface. The dendrimer films were found to be amorphous. The highest mobility was measured for the first generation dendrimer (SBF-(G1)2), which had an average mobility of (6.6 +/- 0.2) × 10-5 cm2/V s and an ON/OFF ratio of 3.0 × 104. As the generation of the dendrimer was increased there was only a slight decrease in the measured mobility in spite of the significantly different molecular sizes of the dendrimers. The mobility of SBF-(G3)2, which had a hydrodynamic radius almost twice of SBF-(G1)2, still had an average mobility of (4.7 +/- 0.6) × 10-5 cm2/V s and an ON/OFF ratio of 2.7 × 103. Density functional theory calculations showed that the highest occupied molecular orbital was distributed over the core and carbazole units meaning that both intra- and intermolecular charge transfer could occur enabling the hole mobility to remain essentially constant even though the dendrimers would pack differently in the solid-state.

  5. Imaging biomarkers to predict response to anti-HER2 (ErbB2) therapy in preclinical models of breast cancer

    Science.gov (United States)

    Shah, Chirayu; Miller, Todd W.; Wyatt, Shelby K.; McKinley, Eliot T.; Olivares, Maria Graciela; Sanchez, Violeta; Nolting, Donald D.; Buck, Jason R.; Zhao, Ping; Ansari, M. Sib; Baldwin, Ronald M.; Gore, John C.; Schiff, Rachel; Arteaga, Carlos L.; Manning, H. Charles

    2010-01-01

    Purpose To evaluate non-invasive imaging methods as predictive biomarkers of response to trastuzumab in mouse models of HER2-overexpressing breast cancer. The correlation between tumor regression and molecular imaging of apoptosis, glucose metabolism, and cellular proliferation was evaluated longitudinally in responding and non-responding tumor-bearing cohorts. Experimental Design Mammary tumors from MMTV/HER2 transgenic female mice were transplanted into syngeneic female mice. BT474 human breast carcinoma cell line xenografts were grown in athymic nude mice. Tumor cell apoptosis (NIR700-Annexin-V accumulation), glucose metabolism ([18F]FDG-PET), and proliferation ([18F]FLT-PET) were evaluated throughout a bi-weekly trastuzumab regimen. Imaging metrics were validated by direct measurement of tumor size and immunohistochemical (IHC) analysis of cleaved caspase-3, phosphorylated AKT (p-AKT) and Ki67. Results NIR700-Annexin-V accumulated significantly in trastuzumab-treated MMTV/HER2 and BT474 tumors that ultimately regressed, but not in non-responding or vehicle-treated tumors. Uptake of [18F]FDG was not affected by trastuzumab treatment in MMTV/HER2 or BT474 tumors. [18F]FLT PET imaging predicted trastuzumab response in BT474 tumors but not in MMTV/HER2 tumors, which exhibited modest uptake of [18F]FLT. Close agreement was observed between imaging metrics and IHC analysis. Conclusions Molecular imaging of apoptosis accurately predicts trastuzumab-induced regression of HER2(+) tumors and may warrant clinical exploration to predict early response to neoadjuvant trastuzumab. Trastuzumab does not appear to alter glucose metabolism substantially enough to afford [18F]FDG-PET significant predictive value in this setting. Although promising in one preclinical model, further studies are required to determine the overall value of [18F]FLT-PET as a biomarker of response to trastuzumab in HER2+ breast cancer. PMID:19584166

  6. Comparative assay of fluorescent antibody test results among twelve European National Reference Laboratories using various anti-rabies conjugates

    DEFF Research Database (Denmark)

    Robardet, E.; Andrieu, S.; Rasmussen, Thomas Bruun

    2013-01-01

    Twelve National Reference Laboratories (NRLs) for rabies have undertaken a comparative assay to assess the comparison of fluorescent antibody test (FAT) results using five coded commercial anti-rabies conjugates (Biorad, Bioveta, Fujirebio, Millipore, and SIFIN conjugates). Homogenized positive...

  7. In vitro and in vivo studies of the combination of IGF1R inhibitor figitumumab (CP-751,871) with HER2 inhibitors trastuzumab and neratinib.

    Science.gov (United States)

    Chakraborty, Ashok K; Zerillo, Cynthia; DiGiovanna, Michael P

    2015-08-01

    The insulin-like growth factor I receptor (IGF1R) has been linked to resistance to HER2-directed therapy with trastuzumab (Herceptin). We examined the anti-tumor activity of figitumumab (CP-751,871), a human monoclonal antibody that blocks IGF1R ligand binding, alone and in combination with the therapeutic anti-HER2 antibody trastuzumab and the pan-HER family tyrosine kinase inhibitor neratinib, using in vitro and in vivo breast cancer model systems. In vitro assays of proliferation, apoptosis, and signaling, and in vivo anti-tumor experiments were conducted in HER2-overexpressing (BT474) and HER2-normal (MCF7) models. We find single-agent activity of the HER2-targeting drugs but not figitumumab in the BT474 model, while the reverse is true in the MCF7 model. However, in both models, combining figitumumab with HER2-targeting drugs shows synergistic anti-proliferative and apoptosis-inducing effects, and optimum inhibition of downstream signaling. In murine xenograft models, synergistic anti-tumor effects were observed in the HER2-normal MCF7 model for the combination of figitumumab with trastuzumab, and, in the HER2-overexpressing BT474 model, enhanced anti-tumor effects were observed for the combination of figitumumab with either trastuzumab or neratinib. Analysis of tumor extracts from the in vivo experiments showed evidence of the most optimal inhibition of downstream signaling for the drug combinations over the single-agent therapies. These results suggest promise for such combinations in treating patients with breast cancer, and that, unlike the case for single-agent therapy, the therapeutic effects of such combinations may be independent of expression levels of the individual receptors or the single-agent activity profile.

  8. Synthesis and anti-angiogenic effect of conjugates between serum albumin and non-steroidal anti-inflammatory drugs

    DEFF Research Database (Denmark)

    Kjær, Birgitte; Struve, Casper; Friis, Tina

    2010-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit tumor growth and angiogenesis. Covalent linkage of naproxen to human serum albumin (HSA) has been shown to target it efficiently to the liver and this may potentially be exploited for liver-selective inhibition of angiogenesis. With the aim...... effect on endothelial cells at or above the level of the non-conjugated NSAIDs in an in vitro angiogenesis assay....

  9. Determination of HER2 gene amplification by chromogenic in situ hybridization (CISH) in archival breast carcinoma.

    Science.gov (United States)

    Zhao, Jianxin; Wu, Rina; Au, Alfred; Marquez, Abbey; Yu, Yibing; Shi, Zuorong

    2002-06-01

    To compare the efficacy of chromogenic in situ hybridization (CISH(TM)) with fluorescence in situ (FISH) hybridization and immunohistochemistry (IHC) in determination of the HER2 status in human breast cancer. HER2 gene amplification was determined on formalin-fixed paraffin-embedded (FFPE) sections of 62 invasive breast cancers by FISH and followed by CISH using a digoxigenin (DIG)-labeled HER2 DNA probe generated by Subtraction Probe Technology (SPT(TM)), and a biotin-labeled chromosome 17 centromeric (chr.17cen) probe. The sections were heat treated and enzyme digested. After in situ hybridization, the HER2 probe was detected with fluorescein (FITC)-anti-DIG for FISH, followed by peroxidase-anti-FITC and diaminobenzidine (DAB) for CISH. The chr.17cen probe was detected with peroxidase-streptavidin and DAB. For CISH application, HER2 gene copies or chromosome 17 centromeres and morphology of cells were easily visualized simultaneously with a 40x objective under bright-field microscope in hematoxylin-counterstained sections. IHC study of HER2 overexpression was performed on adjacent sections using a panel of three HER2 antibodies (TAB 250, CB11, A0485), and staining was scored according to the criteria specified in the HercepTest. HER2 gene amplification detected by CISH was visualized typically as large DAB-stained clusters or by many dots in the nucleus. FISH and CISH identified HER2 gene amplification in 19% of the tumors. Chromosome 17 polysomy was detected in 31% of the tumors. HER2 overexpression was demonstrated in 19% (TAB 250), 23% (CB11), and 36% (A0485) of the tumors. Complete concordance between the results of CISH with FISH, TAB 250, CB11, and A0485 was seen in 100%, 97%, 94%, and 84% of the cases, respectively. By permitting observation of morphology using a bright-field microscope, CISH is an accurate, practical, and economical approach to screen HER2 status in breast cancers. It is a useful methodology for confirming ambiguous IHC results.

  10. Positron annihilation study of polyphenylene dendrimers

    International Nuclear Information System (INIS)

    Marek, T.; Suevegh, K.; Vertes, A.; Ernst, A.; Bauer, R.; Weil, T.; Wiesler, U.; Klapper, M.; Muellen, K.

    2003-01-01

    The free volume of a series of rigid polyphenylene dendrimers was studied by positron lifetime spectroscopy and the experimental data were compared with results from molecular dynamics calculations. Contrary to dendrimers containing flexible repeat units rigid polyphenylene dendrimers proved to contain large stable 'inner' voids of a distinct size between their dendritic branches. The size of the 'inner' cavities increases with the size of the dendrimer. Due to these voids, polyphenylene dendrimers are potentially attractive with respect to the selective incorporation of guest molecules

  11. New dendrimer - peptide host - guest complexes : towards dendrimers as peptide carriers

    NARCIS (Netherlands)

    Boas, U.; Sontjens, S.H.M.; Jensen, K.J.; Christensen, J.B.; Meijer, E.W.

    2002-01-01

    Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions

  12. The relation between survival and expression of HER1 and HER2 depends on the expression of HER3 and HER4

    DEFF Research Database (Denmark)

    Memon, A A; Sorensen, B S; Meldgaard, P

    2006-01-01

    significance of HER1 and HER2 receptors in bladder cancer is controversial and the effect of the expression of different combinations of these receptors on patient survival is not well understood. Therefore, we examined the mRNA expression of all four EGF receptors with real-time polymerase chain reaction......Increased expression of the epidermal growth factor (EGF) receptors, HER1 and HER2 are related to poor prognosis in most cancers studied. Recently, a high expression of the two remaining receptors of the EGF system, HER3 and HER4 has been related to a favourable prognosis. However, prognostic...... in biopsies from 88 patients with bladder cancer, where the survival was followed for a median of 38.5 months (range 1-117 months). Expression of HER1 and HER2 alone showed no correlation with survival. However, a high expression of HER1 together with high expression of HER3 and HER4 correlated to a better...

  13. Optical absorption in compact and extended dendrimers

    International Nuclear Information System (INIS)

    Supritz, C.; Engelmann, A.; Reineker, P.

    2005-01-01

    Dendrimers are highly branched molecules, which are expected to be useful, for example, as efficient artificial light harvesting systems, in nano-technological or in medical applications. There are two different classes of dendrimers: compact dendrimers with constant distance between neighboring branching points throughout the macromolecule and extended dendrimers, where this distance increases from the system periphery to the center. We investigate the linear optical absorption spectra of these dendrimer types using the Frenkel exciton concept. The electron-phonon interaction is taken into account by introducing a heat bath that interacts with the exciton in a stochastic manner. We discuss compact dendrimers with equal excitation energies at all molecules, dendrimers with a functionalized core as well as with a whole branch functionalized. Furthermore the line shape of a compact dendrimer is discussed when neighboring molecules at the periphery interact and when all molecules have randomly distributed excitation energies due to disorder. Finally, we discuss two models for extended dendrimers

  14. Dendrimers for siRNA Delivery

    Directory of Open Access Journals (Sweden)

    Swati Biswas

    2013-02-01

    Full Text Available Since the discovery of the “starburst polymer”, later renamed as dendrimer, this class of polymers has gained considerable attention for numerous biomedical applications, due mainly to the unique characteristics of this macromolecule, including its monodispersity, uniformity, and the presence of numerous functionalizable terminal groups. In recent years, dendrimers have been studied extensively for their potential application as carriers for nucleic acid therapeutics, which utilize the cationic charge of the dendrimers for effective dendrimer-nucleic acid condensation. siRNA is considered a promising, versatile tool among various RNAi-based therapeutics, which can effectively regulate gene expression if delivered successfully inside the cells. This review reports on the advancements in the development of dendrimers as siRNA carriers.

  15. Comparison of central HER2 testing with quantitative total HER2 expression and HER2 homodimer measurements using a novel proximity-based assay.

    Science.gov (United States)

    Huang, Weidong; Reinholz, Monica; Weidler, Jodi; Yolanda, Lie; Paquet, Agnes; Whitcomb, Jeannette; Lingle, Wilma; Jenkins, Robert B; Chen, Beiyun; Larson, Jeffrey S; Tan, Yuping; Sherwood, Thomas; Bates, Michael; Perez, Edith A

    2010-08-01

    The accuracy and reliability of immunohistochemical analysis and in situ hybridization for the assessment of HER2 status remains a subject of debate. We developed a novel assay (HERmark Breast Cancer Assay, Monogram Biosciences, South San Francisco, CA) that provides precise quantification of total HER2 protein expression (H2T) and HER2 homodimers (H2D) in formalin-fixed, paraffin-embedded tissue specimens. H2T and H2D results of 237 breast cancers were compared with those of immunohistochemical studies and fluorescence in situ hybridization (FISH) centrally performed at the Mayo Clinic, Rochester, MN. H2T described a continuum across a wide dynamic range ( approximately 2.5 log). Excluding the equivocal cases, HERmark showed 98% concordance with immunohistochemical studies for positive and negative assay values. For the 94 immunohistochemically equivocal cases, 67% and 39% concordance values were observed between HERmark and FISH for positive and negative assay values, respectively. Polysomy 17 in the absence of HER2 gene amplification did not result in HER2 overexpression as evaluated quantitatively using the HERmark assay.

  16. High p95HER2/HER2 Ratio Associated With Poor Outcome in Trastuzumab-Treated HER2-Positive Metastatic Breast Cancer NCCTG N0337 and NCCTG 98-32-52 (Alliance).

    Science.gov (United States)

    Chumsri, Saranya; Sperinde, Jeff; Liu, Heshan; Gligorov, Joseph; Spano, Jean-Philippe; Antoine, Martine; Moreno Aspitia, Alvaro; Tan, Winston; Winslow, John; Petropoulos, Christos J; Chenna, Ahmed; Bates, Michael; Weidler, Jodi Marie; Huang, Weidong; Dueck, Amylou; Perez, Edith A

    2018-03-12

    Purpose: p95HER2 is a truncated form of HER2 that confers resistance to trastuzumab in vitro , but clinical results have been conflicting to date. Given that p95HER2 levels correlate with total HER2 expression levels, which confer better outcomes, we sought to evaluate the p95HER2/HER2 ratio in the North Central Cancer Treatment Group N0337 and N98-32-52 trials. Experimental Design: The HERmark assay and VeraTag technology (Monogram Biosciences) were used to measure total HER2 and p95HER2 expression levels in 91 patient samples. Results: In the multivariate model, increasing total HER2 level was significantly associated with longer (OS; HR, 0.33; P = 0.002) and decreasing p95HER2 level was significantly associated with longer OS (HR, 4.2; P = 0.01). Total HER2 expression level was significantly associated with longer progression-free survival (PFS) (HR, 0.57; P = 0.04), whereas p95HER2 level was not (HR, 1.7; P = 0.25). However, there was a positive association between p95HER2 and total HER2 expression levels ( R 2 = 0.48; P < 0.001). Consistent with our hypothesis, the ratio of p95HER2/HER2 was significantly associated with worsening PFS (HR, 1.7; P = 0.04) and OS (HR, 2.8; P = 0.002). Patients with the highest tertile of p95HER2/HER2 values had significantly less favorable PFS (HR, 1.8; P = 0.06) and OS (HR, 2.3; P = 0.02). Conclusions: A high p95HER2/HER2 ratio identified patients with metastatic breast cancer with poor outcomes on trastuzumab-based therapies. Further investigation of the p95HER2/HER2 ratio as a potential prognostic or predictive biomarker for HER2-targeted therapy is warranted. Clin Cancer Res; 1-6. ©2018 AACR. ©2018 American Association for Cancer Research.

  17. Color feature extraction of HER2 Score 2+ overexpression on breast cancer using Image Processing

    Directory of Open Access Journals (Sweden)

    Muhimmah Izzati

    2018-01-01

    Full Text Available One of the major challenges in the development of early diagnosis to assess HER2 status is recognized in the form of Gold Standard. The accuracy, validity and refraction of the Gold Standard HER2 methods are widely used in laboratory (Perez, et al., 2014. Method determining the status of HER2 (human epidermal growth factor receptor 2 is affected by reproductive problems and not reliable in predicting the benefit from anti-HER2 therapy (Nuciforo, et al., 2016. We extracted color features by methods adopting Statistics-based segmentation using a continuous-scale naïve Bayes approach. In this study, there were three parts of the main groups, namely image acquisition, image segmentation, and image testing. The stages of image acquisition consisted of image data collection and color deconvolution. The stages of image segmentation consisted of color features, classifier training, classifier prediction, and skeletonization. The stages of image testing were image testing, expert validation, and expert validation results. Area segmentation of the membrane is false positive and false negative. False positive and false negative from area are called the area of system failure. The failure of the system can be validated by experts that the results of segmentation region is not membrane HER2 (noise and the segmentation of the cytoplasm region. The average from 40 data of HER2 score 2+ membrane images show that 75.13% of the area is successfully recognized by the system.

  18. Investigation of a potential macromolecular MRI contrast agent prepared from PPI (G = 2, polypropyleneimine, generation 2) dendrimer bifunctional chelates

    Science.gov (United States)

    Wang, Jianxin Steven

    The long-term objective is to develop magnetic resonance (MR) contrast agents that actively and passively target tumors for diagnosis and therapy. Many diagnostic imaging techniques for cancer lack specificity. A dendrimer based magnetic resonance imaging contrast agent has been developed with large proton relaxation enhancements and high molecular relaxivities. A new type of linear dendrimer based MRI contrast agent that is built from the polypropyleneimine and polyamidoamine dendrimers in which free amines have been conjugated to the chelate DTPA, which further formed the complex with Gadolinium (Gd) was studied. The specific research goals were to test the hypothesis that a linear chelate with macromolecular agents can be used in vitro and in vivo. This work successfully examined the adequacy and viability of the application for this agent in vitro and in vivo. A small animal whole body counter was designed and constructed to allow us to monitor biodistribution and kinetic mechanisms using a radioisotope labeled complex. The procedures of metal labeling, separation and purification have been established from this work. A biodistribution study has been performed using radioisotope induced organ/tissue counting and gamma camera imaging. The ratio of percentage of injected dose per gram organ/tissue for kidney and liver is 3.71 from whole body counter and 3.77 from the gamma camera. The results suggested that retention of Gd (III) is too high and a more kinetically stable chelate should be developed. The pharmacokinetic was evaluated in the whole animal model with the whole body clearance, and a kinetics model was developed. The pharmacokinetic results showed a bi-exponential decay in the animal model with two component excretion constants 1.43e(-5) and 0.0038511, which give half-lives of 3 hours and 33.6 days, respectively. Magnetic resonance imaging of this complex resulted in a 52% contrast enhancement in the rat kidney following the agents' administration in

  19. Production of anti-fullerene C{sub 60} polyclonal antibodies and study of their interaction with a conjugated form of fullerene

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, O. D., E-mail: odhendrick@gmail.com; Fedyunina, N. S. [Russian Academy of Sciences, Institute of Biochemistry (Russian Federation); Martianov, A. A. [Moscow State University (Russian Federation); Zherdev, A. V.; Dzantiev, B. B. [Russian Academy of Sciences, Institute of Biochemistry (Russian Federation)

    2011-09-15

    The aim of this study was to produce anti-fullerene C{sub 60} antibodies for the development of detection systems for fullerene C{sub 60} derivatives. To produce anti-fullerene C{sub 60} antibodies, conjugates of the fullerene C{sub 60} carboxylic derivative with thyroglobulin, soybean trypsin inhibitor, and bovine serum albumin were synthesized by carbodiimide activation and characterized. Immunization of rabbits by the conjugates led to the production of polyclonal anti-fullerene antibodies. The specificity of the immune response to fullerene was investigated. Indirect competitive immunoenzyme assay was developed for the determination of conjugated fullerene with detection limits of 0.04 ng/mL (calculated for coupled C{sub 60}) and 0.4 ng/mL (accordingly to total fullerene-protein concentration).

  20. Stopped-flow kinetic studies of poly(amidoamine) dendrimer-calf thymus DNA to form dendriplexes.

    Science.gov (United States)

    Dey, Debabrata; Kumar, Santosh; Maiti, Souvik; Dhara, Dibakar

    2013-11-07

    Poly(amidoamine) (PAMAM) dendrimers are known to be highly efficient nonviral carriers in gene delivery. Dendrimer-mediated transfection is known to be a function of the dendrimer to DNA charge ratio as well as the size of the dendrimer. In the present study, the binding kinetics of four PAMAM dendrimers (G1, G2, G3, and G4) with calf thymus DNA (CT-DNA) has been studied using stopped-flow fluorescence spectroscopy. The effect of dendrimer-to-DNA charge ratio and dendrimer generation on the binding kinetics was investigated. In most cases, the results of dendrimer-CT-DNA binding can be explained by a two-step reaction mechanism: a rapid electrostatic binding between the dendrimer and DNA, followed by a conformational change of the dendrimer-DNA complex that ultimately leads to DNA condensation. It was observed that the charge ratio on the dendrimer and the DNA phosphate groups, as well as the dendrimer generation (size), has a marked effect on the kinetics of binding between the DNA and the dendrimers. The rate constant (k'1) of the first step was much higher compared to that of the second step (k'2), and both were found to increase with an increase in dendrimer concentration. Among the four generations of dendrimers, G4 exhibited significantly faster binding kinetics compared to the three smaller generation dendrimers.

  1. Strong and long-lasting antinociceptive and anti-inflammatory conjugate of naturally occurring oleanolic acid and aspirin

    Directory of Open Access Journals (Sweden)

    Barbara Bednarczyk-Cwynar

    2016-07-01

    Full Text Available The conjugate 8 was obtained as a result of condensation of 3-hydroxyiminooleanolic acid morfolide (7 and aspirin in dioxane. Analgesic effect of OAO-ASA (8 for the range of doses 0.3 – 300.0 mg/kg (p.o. was performed in mice using a hot plate test. Anti-inflammatory activity was assessed on carrageenan-induced paw edema in rats for the same range of doses. The conjugate OAO-ASA (8 did not significantly change locomotor activity of mice, therefore sedative properties of the compound should be excluded. The compound 8 proved a simple, proportional, dose-dependent analgesic action and expressed strong anti-inflammatory activity showing a reversed U-shaped, dose-dependent relation with its maximum at 30.0 mg/kg. After its combined administration with morphine (MF, 5.0 mg/kg, s.c. the lowering of antinociceptive activity was found; however, the interaction with naloxone (NL, 3.0 mg/kg, s.c. did not affect the antinociceptive effect of OAO-ASA (8, therefore its opioid mechanism of action should be rather excluded. After combined administration with acetylsalicylic acid (ASA, 300.0 mg/kg, p.o. in hot-plate test, the examined compound 8 enhanced the antinociceptive activity in significant way. It also shows that rather the whole molecule is responsible for the antinociceptive and anti-inflammatory effect of the tested compound 8, however it cannot be excluded that the summarizing effect is produced by ASA released from the compound 8 and the rest of triterpene derivative. The occurrence of tolerance for triterpenic derivative 8 was not observed, since the analgesic and anti-inflammatory effects after chronic administration of the conjugate OAO-ASA (8 was on the same level as after its single treatment. It seemed that the anti-inflammatory mechanism of action of OAO-ASA (8 is not simple, even its chronic administration lowered both blood concentration of IL-6 and mRNA IL-6 expression. However, the effects of the conjugate OAO-ASA (8 on TNF-α level

  2. Specific Conjugation of the Hinge Region for Homogeneous Preparation of Antibody Fragment-Drug Conjugate: A Case Study for Doxorubicin-PEG-anti-CD20 Fab' Synthesis.

    Science.gov (United States)

    Zhou, Zhan; Zhang, Jing; Zhang, Yan; Ma, Guanghui; Su, Zhiguo

    2016-01-20

    Conventional preparation strategies for antibody-drug conjugates (ADCs) result in heterogeneous products with various molecular sizes and species. In this study, we developed a homogeneous preparation strategy by site-specific conjugation of the anticancer drug with an antibody fragment. The model drug doxorubicin (DOX) was coupled to the Fab' fragment of anti-CD20 IgG at its permissive sites through a heterotelechelic PEG linker, generating an antibody fragment-drug conjugate (AFDC). Anti-CD20 IgG was digested and reduced specifically with β-mercaptoethylamine to generate the Fab' fragment with two free mercapto groups in its hinge region. Meanwhile, DOX was conjugated with α-succinimidylsuccinate ω-maleimide polyethylene glycol (NHS-PEG-MAL) to form MAL-PEG-DOX, which was subsequently linked to the free mercapto containing Fab' fragment to form a Fab'-PEG-DOX conjugate. The dual site-specific bioconjugation was achieved through the combination of highly selective reduction of IgG and introduction of heterotelechelic PEG linker. The resulting AFDC provides an utterly homogeneous product, with a definite ratio of one fragment to two drugs. Laser confocal microscopy and cell ELISA revealed that the AFDC could accumulate in the antigen-positive Daudi tumor cell. In addition, the Fab'-PEG-DOX retained appreciable targeting ability and improved antitumor activity, demonstrating an excellent therapeutic effect on the lymphoma mice model for better cure rate and significantly reduced side effects.

  3. A TORC2-Akt feedforward topology underlies HER3 resiliency in HER2-amplified cancers

    Science.gov (United States)

    Amin, Dhara N.; Ahuja, Deepika; Yaswen, Paul; Moasser, Mark M.

    2015-01-01

    The requisite role of HER3 in HER2-amplified cancers is beyond what would be expected as a dimerization partner or effector substrate and it exhibits a substantial degree of resiliency that mitigates the effects of HER2-inhibitor therapies. To better understand the roots of this resiliency, we conducted an in-depth chemical-genetic interrogation of the signaling network downstream of HER3. A unique attribute of these tumors is the deregulation of TORC2. The upstream signals that ordinarily maintain TORC2 signaling are lost in these tumors, and instead TORC2 is driven by Akt. We find that in these cancers HER3 functions as a buffering arm of an Akt-TORC2 feed-forward loop that functions as a self-perpetuating module. This network topology alters the role of HER3 from a conditionally engaged ligand-driven upstream physiologic signaling input to an essential component of a concentric signaling throughput highly competent at preservation of homeostasis. The competence of this signaling topology is evident in its response to perturbation at any of its nodes. Thus a critical pathophysiological event in the evolution of HER2-amplified cancers is the loss of the input signals that normally drive TORC2 signaling, repositioning it under Akt dependency and fundamentally altering the role of HER3. This reprogramming of the downstream network topology is a key aspect in the pathogenesis of HER2-amplified cancers and constitutes a formidable barrier in the targeted therapy of these cancers. PMID:26438156

  4. Interactions of poly(amidoamine) dendrimers with human serum albumin: binding constants and mechanisms.

    Science.gov (United States)

    Giri, Jyotsnendu; Diallo, Mamadou S; Simpson, André J; Liu, Yi; Goddard, William A; Kumar, Rajeev; Woods, Gwen C

    2011-05-24

    The interactions of nanomaterials with plasma proteins have a significant impact on their in vivo transport and fate in biological fluids. This article discusses the binding of human serum albumin (HSA) to poly(amidoamine) [PAMAM] dendrimers. We use protein-coated silica particles to measure the HSA binding constants (K(b)) of a homologous series of 19 PAMAM dendrimers in aqueous solutions at physiological pH (7.4) as a function of dendrimer generation, terminal group, and core chemistry. To gain insight into the mechanisms of HSA binding to PAMAM dendrimers, we combined (1)H NMR, saturation transfer difference (STD) NMR, and NMR diffusion ordered spectroscopy (DOSY) of dendrimer-HSA complexes with atomistic molecular dynamics (MD) simulations of dendrimer conformation in aqueous solutions. The binding measurements show that the HSA binding constants (K(b)) of PAMAM dendrimers depend on dendrimer size and terminal group chemistry. The NMR (1)H and DOSY experiments indicate that the interactions between HSA and PAMAM dendrimers are relatively weak. The (1)H NMR STD experiments and MD simulations suggest that the inner shell protons of the dendrimers groups interact more strongly with HSA proteins. These interactions, which are consistently observed for different dendrimer generations (G0-NH(2)vs G4-NH(2)) and terminal groups (G4-NH(2)vs G4-OH with amidoethanol groups), suggest that PAMAM dendrimers adopt backfolded configurations as they form weak complexes with HSA proteins in aqueous solutions at physiological pH (7.4).

  5. Interaction of PAMAM dendrimers with bovine insulin depends on nanoparticle end-groups

    International Nuclear Information System (INIS)

    Nowacka, Olga; Milowska, Katarzyna; Bryszewska, Maria

    2015-01-01

    We have looked at the interactions between polyamidoamine (PAMAM) dendrimers with different terminal groups (−COOH, −NH 2 , −OH) and bovine insulin. The influence of PAMAM dendrimers on insulin was tested by measuring zeta potential and fluorescence quenching. The secondary structure of insulin in the presence of dendrimers was examined by circular dichroism. The effect of dendrimers on dithiotreitol-induced aggregation of insulin was investigated by spectrophotometry. Dendrimers quenched the fluorescence of insulin, but did not change its secondary structure. Thus dendrimers neither induce hormone aggregation nor inhibit the aggregation process induced by dithiotreitol (DTT), except at 0.01 µmol/l. Dendrimers–insulin interactions are mainly electrostatic. - Highlight: • The interactions between PAMAM dendrimers and insulin were investigated. • The PAMAM dendrimers can quench the fluorescence of insulin. • The PAMAM dendrimers did not change the secondary structure of insulin. • Dendrimers did not induce aggregation of hormone. • Dendrimers–insulin interaction is mainly electrostatic

  6. Dendrimer-magnetic nanostructure: a Monte Carlo simulation

    Science.gov (United States)

    Jabar, A.; Masrour, R.

    2017-11-01

    In this paper, the magnetic properties of ternary mixed spins (σ,S,q) Ising model on a dendrimer nanostructure are studied using Monte Carlo simulations. The ground state phase diagrams of dendrimer nanostructure with ternary mixed spins σ = 1/2, S = 1 and q = 3/2 Ising model are found. The variation of the thermal total and partial magnetizations with the different exchange interactions, the external magnetic fields and the crystal fields have been also studied. The reduced critical temperatures have been deduced. The magnetic hysteresis cycles have been discussed. In particular, the corresponding magnetic coercive filed values have been deduced. The multiples hysteresis cycles are found. The dendrimer nanostructure has several applications in the medicine.

  7. Single-cell quantitative HER2 measurement identifies heterogeneity and distinct subgroups within traditionally defined HER2-positive patients.

    Science.gov (United States)

    Onsum, Matthew D; Geretti, Elena; Paragas, Violette; Kudla, Arthur J; Moulis, Sharon P; Luus, Lia; Wickham, Thomas J; McDonagh, Charlotte F; MacBeath, Gavin; Hendriks, Bart S

    2013-11-01

    Human epidermal growth factor receptor 2 (HER2) is an important biomarker for breast and gastric cancer prognosis and patient treatment decisions. HER2 positivity, as defined by IHC or fluorescent in situ hybridization testing, remains an imprecise predictor of patient response to HER2-targeted therapies. Challenges to correct HER2 assessment and patient stratification include intratumoral heterogeneity, lack of quantitative and/or objective assays, and differences between measuring HER2 amplification at the protein versus gene level. We developed a novel immunofluorescence method for quantitation of HER2 protein expression at the single-cell level on FFPE patient samples. Our assay uses automated image analysis to identify and classify tumor versus non-tumor cells, as well as quantitate the HER2 staining for each tumor cell. The HER2 staining level is converted to HER2 protein expression using a standard cell pellet array stained in parallel with the tissue sample. This approach allows assessment of HER2 expression and heterogeneity within a tissue section at the single-cell level. By using this assay, we identified distinct subgroups of HER2 heterogeneity within traditional definitions of HER2 positivity in both breast and gastric cancers. Quantitative assessment of intratumoral HER2 heterogeneity may offer an opportunity to improve the identification of patients likely to respond to HER2-targeted therapies. The broad applicability of the assay was demonstrated by measuring HER2 expression profiles on multiple tumor types, and on normal and diseased heart tissues. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  8. Interaction between viologen-phosphorus dendrimers and α-synuclein

    International Nuclear Information System (INIS)

    Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

    2013-01-01

    In this study the interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: ► Interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was investigated. ► Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. ► Dendrimers caused red-shift in maximum of fluorescence. ► Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

  9. Human epidermal growth factor receptor 2 (HER2) immunoreactivity

    DEFF Research Database (Denmark)

    Rasmussen, Anne-Sofie Schrohl; Pedersen, Hans Christian; Jensen, Sussie Steen

    2011-01-01

    The availability of specific antibody-based test systems is essential to testing of HER2 protein expression. Here, we mapped epitopes recognized by three pharmacodiagnostic HER2 antibodies and investigated their specificity towards peptides and fusion proteins homologous to the intracellular doma...... domains of HER1, HER2, HER3 and HER4. The investigated antibodies were PATHWAY(®) HER2 (clone 4B5; Ventana Medical Systems Inc., Tucson, AZ, USA), HercepTest™ (Dako Denmark A/S, Glostrup, Denmark), and Oracle(®) HER2 (clone CB11; Leica Microsystems GmbH, Wetzlar, Germany)....

  10. Heterologous human/rat HER2-specific exosome-targeted T cell vaccine stimulates potent humoral and CTL responses leading to enhanced circumvention of HER2 tolerance in double transgenic HLA-A2/HER2 mice.

    Science.gov (United States)

    Xie, Yufeng; Wu, Jie; Xu, Aizhang; Ahmeqd, Shahid; Sami, Amer; Chibbar, Rajni; Freywald, Andrew; Zheng, Changyu; Xiang, Jim

    2018-03-07

    DNA vaccines composed of heterologous human HER2 and rat neu sequences induce stronger antibody response and protective antitumor immunity than either HER2 or neu DNA vaccines in transgenic mice. We previously developed HER2-specific exosome-targeted T-cell vaccine HER2-T EXO capable of stimulating HER2-specific CD8 + T-cell responses, but only leading to partial protective immunity in double-transgenic HLA-A2/HER2 mice with self-immune tolerance to HER2. Here, we constructed an adenoviral vector AdV HuRt expressing HuRt fusion protein composed of NH 2 -HER2 1-407 (Hu) and COOH-neu 408-690 (Rt) fragments, and developed a heterologous human/rat HER2-specific exosome-targeted T-cell vaccine HuRt-T EXO using polyclonal CD4 + T-cells uptaking exosomes released by AdV HuRt -transfected dendritic cells. We found that the HuRt-T EXO vaccine stimulates enhanced CD4 + T-cell responses leading to increased induction of HER2-specific antibody (∼70 µg/ml) compared to that (∼40 µg/ml) triggered by the homologous HER2-T EXO vaccine. By using PE-H-2K d /HER2 23-71 tetramer, we determined that HuRt-T EXO stimulates stronger HER2-specific CD8 + T-cell responses eradicating 90% of HER2-specific target cells, while HER2-T EXO -induced CD8 + T-cell responses only eliminating 53% targets. Furthermore, HuRt-T EXO , but not HER2-T EXO vaccination, is capable of suppressing early stage-established HER2-expressing 4T1 HER2 breast cancer in its lung metastasis or subcutaneous form in BALB/c mice, and of completely protecting transgenic HLA-A2/HER2 mice from growth of HLA-A2/HER2-expressing BL6-10 A2/HER2 melanoma. HuRt-T EXO -stimulated HER2-specific CD8 + T-cells not only are cytolytic to trastuzumab-resistant HLA-A2/HER2-expressing BT474/A2 breast tumor cells in vitro but also eradicates pre-established BT474/A2 tumors in athymic nude mice. Therefore, our novel heterologous human/rat HER2-specific T-cell vaccine HuRt-T EXO, circumventing HER2 tolerance, may provide a new

  11. Interplay between Natural Killer Cells and Anti-HER2 Antibodies: Perspectives for Breast Cancer Immunotherapy

    Directory of Open Access Journals (Sweden)

    Aura Muntasell

    2017-11-01

    Full Text Available Overexpression of the human epidermal growth factor receptor 2 (HER2 defines a subgroup of breast tumors with aggressive behavior. The addition of HER2-targeted antibodies (i.e., trastuzumab, pertuzumab to chemotherapy significantly improves relapse-free and overall survival in patients with early-stage and advanced disease. Nonetheless, considerable proportions of patients develop resistance to treatment, highlighting the need for additional and co-adjuvant therapeutic strategies. HER2-specific antibodies can trigger natural killer (NK cell-mediated antibody-dependent cellular cytotoxicity and indirectly enhance the development of tumor-specific T cell immunity; both mechanisms contributing to their antitumor efficacy in preclinical models. Antibody-dependent NK cell activation results in the release of cytotoxic granules as well as the secretion of pro-inflammatory cytokines (i.e., IFNγ and TNFα and chemokines. Hence, NK cell tumor suppressive functions include direct cytolytic killing of tumor cells as well as the regulation of subsequent antitumor adaptive immunity. Albeit tumors with gene expression signatures associated to the presence of cytotoxic lymphocyte infiltrates benefit from trastuzumab-based treatment, NK cell-related biomarkers of response/resistance to HER2-specific therapeutic antibodies in breast cancer patients remain elusive. Several variables, including (i the configuration of the patient NK cell repertoire; (ii tumor molecular features (i.e., estrogen receptor expression; (iii concomitant therapeutic regimens (i.e., chemotherapeutic agents, tyrosine kinase inhibitors; and (iv evasion mechanisms developed by progressive breast tumors, have been shown to quantitatively and qualitatively influence antibody-triggered NK cell responses. In this review, we discuss possible interventions for restoring/enhancing the therapeutic activity of HER2 therapeutic antibodies by harnessing NK cell antitumor potential through

  12. Synthesis of Polyamidoamine Dendrimer for Encapsulating Tetramethylscutellarein for Potential Bioactivity Enhancement.

    Science.gov (United States)

    Shadrack, Daniel M; Mubofu, Egid B; Nyandoro, Stephen S

    2015-11-04

    The biomedical potential of flavonoids is normally restricted by their low water solubility. However, little has been reported on their encapsulation into polyamidoamine (PAMAM) dendrimers to improve their biomedical applications. Generation four (G4) PAMAM dendrimer containing ethylenediaminetetraacetic acid core with acrylic acid and ethylenediamine as repeating units was synthesized by divergent approach and used to encapsulate a flavonoid tetramethylscutellarein (TMScu, 1) to study its solubility and in vitro release for potential bioactivity enhancement. The as-synthesized dendrimer and the dendrimer-TMScu complex were characterized by spectroscopic and spectrometric techniques. The encapsulation of 1 into dendrimer was achieved by a co-precipitation method with the encapsulation efficiency of 77.8% ± 0.69% and a loading capacity of 6.2% ± 0.06%. A phase solubility diagram indicated an increased water solubility of 1 as a function of dendrimer concentration at pH 4.0 and 7.2. In vitro release of 1 from its dendrimer complex indicated high percentage release at pH 4.0. The stability study of the TMScu-dendrimer at 0, 27 and 40 °C showed the formulations to be stable when stored in cool and dark conditions compared to those stored in light and warmer temperatures. Overall, PAMAM dendrimer-G4 is capable of encapsulating 1, increasing its solubility and thus could enhance its bioactivity.

  13. RNA-Based TWIST1 Inhibition via Dendrimer Complex to Reduce Breast Cancer Cell Metastasis

    Directory of Open Access Journals (Sweden)

    James Finlay

    2015-01-01

    Full Text Available Breast cancer is the leading cause of cancer-related deaths among women in the United States, and survival rates are lower for patients with metastases and/or triple-negative breast cancer (TNBC; ER, PR, and Her2 negative. Understanding the mechanisms of cancer metastasis is therefore crucial to identify new therapeutic targets and develop novel treatments to improve patient outcomes. A potential target is the TWIST1 transcription factor, which is often overexpressed in aggressive breast cancers and is a master regulator of cellular migration through epithelial-mesenchymal transition (EMT. Here, we demonstrate an siRNA-based TWIST1 silencing approach with delivery using a modified poly(amidoamine (PAMAM dendrimer. Our results demonstrate that SUM1315 TNBC cells efficiently take up PAMAM-siRNA complexes, leading to significant knockdown of TWIST1 and EMT-related target genes. Knockdown lasts up to one week after transfection and leads to a reduction in migration and invasion, as determined by wound healing and transwell assays. Furthermore, we demonstrate that PAMAM dendrimers can deliver siRNA to xenograft orthotopic tumors and siRNA remains in the tumor for at least four hours after treatment. These results suggest that further development of dendrimer-based delivery of siRNA for TWIST1 silencing may lead to a valuable adjunctive therapy for patients with TNBC.

  14. Efficient VEGF targeting delivery of DOX using Bevacizumab conjugated SiO2@LDH for anti-neuroblastoma therapy.

    Science.gov (United States)

    Zhu, Rongrong; Wang, Zhaoqi; Liang, Peng; He, Xiaolie; Zhuang, Xizhen; Huang, Ruiqi; Wang, Mei; Wang, Qigang; Qian, Yechang; Wang, Shilong

    2017-11-01

    Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and is highly expressed in carcinoma, which make it an important target for tumor targeting therapy. Neuroblastoma is the main cause for cancer-related death in children. Like most solid tumors, it is also accompanied with the overexpression of VEGF. Doxorubicin Hydrochloride (DOX), a typical chemotherapeutic agent, exhibits efficient anticancer activities for various cancers. However, DOX, without targeting ability, usually causes severe damage to normal tissues. To overcome the shortages, we designed a novel nano-composite, which is Bevacizumab (Bev) modified SiO 2 @LDH nanoparticles (SiO 2 @LDH-Bev), loading with DOX to achieve targeting ability and curative efficiency. SiO 2 @LDH-DOX and SiO 2 @LDH-Bev-DOX nanoparticles were synthesized and the physicochemical properties were characterized by TEM detection, Zeta potential analysis, FTIR, Raman and XPS analysis. Then in vitro and in vivo anti-neuroblastoma efficiency, targeting ability and mechanisms of anti-carcinoma and anti-angiogenesis of SiO 2 @LDH-Bev-DOX were explored. Our results indicated that we obtained the core-shell structure SiO 2 @LDH-Bev with an average diameter of 253±10nm and the amount of conjugated Bev was 4.59±0.38μg/mg SiO 2 @LDH-Bev. SiO 2 @LDH-Bev-DOX could improve the cellular uptake and the targeting effect of DOX to brain and tumor, enhance the anti-neuroblastoma and anti-angiogenesis efficiency both in vitro and in vivo, and alleviate side effects of DOX sharply, especially hepatic injury. In addition, we also demonstrated that angiogenesis inhibitory effect was mediated by DOX and VEGF triggered signal pathways, including PI3K/Akt, Raf/MEK/ERK, and adhesion related pathways. In summary, SiO 2 @LDH-Bev could be a potential VEGF targeting nanocarrier applied in VEGF positive cancer therapy. This paper explored that a novel core-shell structure nanomaterial SiO 2 @LDH and modified SiO 2 @LDH with

  15. The mannosylated extracellular domain of Her2/neu produced in P. pastoris induces protective antitumor immunity

    International Nuclear Information System (INIS)

    Dimitriadis, Alexios; Gontinou, Chrysanthi; Baxevanis, Constantin N; Mamalaki, Avgi

    2009-01-01

    Her2/neu is overexpressed in various human cancers of epithelial origin and is associated with increased metastatic potential and poor prognosis. Several attempts have been made using the extracellular domain of Her2/neu (ECD/Her2) as a prophylactic vaccine in mice with no success in tumor prevention. The extracellular domain of Her2/neu (ECD/Her2) was expressed in yeast P. pastoris, in a soluble highly mannosylated form. The immune response of the immunization with this recombinant ECD/Her2 was analyzed using immunoprecipitation and western blot analysis, proliferation and cytotoxicity assays as well as specific tumor growth assays. Mannosylated ECD/Her2 elicited a humoral response with HER2/neu specific antibodies in vaccinated mice, which were able to reduce the proliferation rate of cancer cells in vitro. Moreover, it elicited a cellular response with Her2/neu-specific CTL capable of lysing tumor cells, in vitro. When immunized Balb/c and HHD mice were challenged with Her2/neu-overexpressing cells, tumor growth was inhibited. Here we report on the efficacy of the extracellular domain of human Her2/neu produced in yeast P. pastoris, which confers mannosylation of the protein, to act as a potent anti-tumor vaccine against Her2/neu overexpressing tumors. Specific cellular and humoral responses were observed as well as efficacy

  16. Dendrimer-based Macromolecular MRI Contrast Agents: Characteristics and Application

    Directory of Open Access Journals (Sweden)

    Hisataka Kobayashi

    2003-01-01

    Full Text Available Numerous macromolecular MRI contrast agents prepared employing relatively simple chemistry may be readily available that can provide sufficient enhancement for multiple applications. These agents operate using a ~100-fold lower concentration of gadolinium ions in comparison to the necessary concentration of iodine employed in CT imaging. Herein, we describe some of the general potential directions of macromolecular MRI contrast agents using our recently reported families of dendrimer-based agents as examples. Changes in molecular size altered the route of excretion. Smaller-sized contrast agents less than 60 kDa molecular weight were excreted through the kidney resulting in these agents being potentially suitable as functional renal contrast agents. Hydrophilic and larger-sized contrast agents were found better suited for use as blood pool contrast agents. Hydrophobic variants formed with polypropylenimine diaminobutane dendrimer cores created liver contrast agents. Larger hydrophilic agents are useful for lymphatic imaging. Finally, contrast agents conjugated with either monoclonal antibodies or with avidin are able to function as tumor-specific contrast agents, which also might be employed as therapeutic drugs for either gadolinium neutron capture therapy or in conjunction with radioimmunotherapy.

  17. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    International Nuclear Information System (INIS)

    Fernandez, L.; Sigal, E.; Santo, M.; Otero, L.; Silber, J. J.

    2011-01-01

    The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazole-2-yl) carbamate, albendazole (ABZ) using polyamidoamine (PAMAM) dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3), with hydroxyl terminal groups (G3OH) and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5), were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by 1 H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups. (author)

  18. Novel HER2 Aptamer Selectively Delivers Cytotoxic Drug to HER2-positive Breast Cancer Cells in Vitro

    Directory of Open Access Journals (Sweden)

    Liu Zhe

    2012-07-01

    Full Text Available Abstract Background Aptamer-based tumor targeted drug delivery system is a promising approach that may increase the efficacy of chemotherapy and reduce the related toxicity. HER2 protein is an attractive target for tumor-specific drug delivery because of its overexpression in multiple malignancies, including breast, gastric, ovarian, and lung cancers. Methods In this paper, we developed a new HER2 aptamer (HB5 by using systematic evolution of ligands by exponential enrichment technology (SELEX and exploited its role as a targeting ligand for delivering doxorubicin (Dox to breast cancer cells in vitro. Results The selected aptamer was an 86-nucleotide DNA molecule that bound to an epitope peptide of HER2 with a Kd of 18.9 nM. The aptamer also bound to the extracellular domain (ECD of HER2 protein with a Kdof 316 nM, and had minimal cross reactivity to albumin or trypsin. In addition, the aptamer was found to preferentially bind to HER2-positive but not HER2-negative breast cancer cells. An aptamer-doxorubicin complex (Apt-Dox was formulated by intercalating Dox into the DNA structure of HB5. The Apt-Dox complex could selectively deliver Dox to HER2-positive breast cancer cells while reducing the drug intake by HER2-negative cells in vitro. Moreover, Apt-Dox retained the cytotoxicity of Dox against HER2-positive breast cancer cells, but reduced the cytotoxicity to HER2-negative cells. Conclusions The results suggest that the selected HER2 aptamer may have application potentials in targeted therapy against HER2-positive breast cancer cells.

  19. Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein

    Energy Technology Data Exchange (ETDEWEB)

    Milowska, Katarzyna, E-mail: milowska@biol.uni.lodz.pl [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Grochowina, Justyna [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de I' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); Bryszewska, Maria; Gabryelak, Teresa [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland)

    2013-02-15

    In this study the interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: Black-Right-Pointing-Pointer Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was investigated. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. Black-Right-Pointing-Pointer Dendrimers caused red-shift in maximum of fluorescence. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

  20. Heat Shock Protein 90 (HSP90 and Her2 in Adenocarcinomas of the Esophagus

    Directory of Open Access Journals (Sweden)

    Julia Slotta-Huspenina

    2014-06-01

    Full Text Available Her2 overexpression and amplification can be found in a significant subset of esophageal adenocarcinomas. The activity of Her2 has been shown to be modulated by molecular chaperones such as HSP90. We analyzed expression/amplification data for HSP90 and Her2 on 127 primary resected esophageal adenocarcinomas in order to evaluate a possible relationship between these two molecules. HSP90 expression determined by immunohistochemistry was observed in various levels. Thirty nine (39 tumors (30.7% were classified as Her2-positive according to their immunoreactivity and amplification status. There was a significant correlation between HSP90 expression and Her2-status (p = 0.008. This could also be demonstrated by quantitative protein expression analysis with reverse phase protein arrays (r = 0.9; p < 0.001. Her2-status was associated withpT-category (p = 0.041, lymph node metastases (p = 0.049 and tumor differentiation (p = 0.036 with a higher percentage of cases with negative Her2 status in lower tumor stagesA negative Her2-status was also associated with better survival in univariate and multivariate analysis (p = 0.001 and p = 0.014. For HSP90, no associations between clinical and pathological parameters were found. The observed association between HSP90 expression and Her2 suggests a co-regulation of these molecules in at least a subset of esophageal adenocarcinomas. Anti-HSP90 drugs, which recently have been introduced in cancer treatment, may also be an option for these tumors by targeting HSP90 alone or in combination with Her2.

  1. Heat Shock Protein 90 (HSP90) and Her2 in Adenocarcinomas of the Esophagus

    Energy Technology Data Exchange (ETDEWEB)

    Slotta-Huspenina, Julia; Becker, Karl-Friedrich [Institute of Pathology, Technische Universität München, München 81765 (Germany); Feith, Marcus [Department of Surgery, Klinikum Rechts der Isar der Technischen Universität München, München 81622 (Germany); Walch, Axel [Institute of Pathology, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Neuherberg 85764 (Germany); Langer, Rupert, E-mail: rupert.langer@pathology.unibe.ch [Institute of Pathology, University of Bern, Bern 3010 (Switzerland)

    2014-06-27

    Her2 overexpression and amplification can be found in a significant subset of esophageal adenocarcinomas. The activity of Her2 has been shown to be modulated by molecular chaperones such as HSP90. We analyzed expression/amplification data for HSP90 and Her2 on 127 primary resected esophageal adenocarcinomas in order to evaluate a possible relationship between these two molecules. HSP90 expression determined by immunohistochemistry was observed in various levels. Thirty nine (39) tumors (30.7%) were classified as Her2-positive according to their immunoreactivity and amplification status. There was a significant correlation between HSP90 expression and Her2-status (p = 0.008). This could also be demonstrated by quantitative protein expression analysis with reverse phase protein arrays (r = 0.9; p < 0.001). Her2-status was associated withpT-category (p = 0.041), lymph node metastases (p = 0.049) and tumor differentiation (p = 0.036) with a higher percentage of cases with negative Her2 status in lower tumor stagesA negative Her2-status was also associated with better survival in univariate and multivariate analysis (p = 0.001 and p = 0.014). For HSP90, no associations between clinical and pathological parameters were found. The observed association between HSP90 expression and Her2 suggests a co-regulation of these molecules in at least a subset of esophageal adenocarcinomas. Anti-HSP90 drugs, which recently have been introduced in cancer treatment, may also be an option for these tumors by targeting HSP90 alone or in combination with Her2.

  2. Chalcone dendrimer stabilized core-shell nanoparticles—a comparative study on Co@TiO2, Ag@TiO2 and Co@AgCl nanoparticles for antibacterial and antifungal activity

    Science.gov (United States)

    Vanathi Vijayalakshmi, R.; Praveen Kumar, P.; Selvarani, S.; Rajakumar, P.; Ravichandran, K.

    2017-10-01

    A series of core@shell nanoparticles (Co@TiO2, Ag@TiO2 and Co@AgCl) stabilized with zeroth generation triazolylchalcone dendrimer was synthesized using reduction transmetalation method. The coordination of chalcone dendrimer with silver ions was confirmed by UV-vis spectroscopy. The NMR spectrum ensures the number of protons and carbon signals in the chalcone dendrimer. The prepared samples were structurally characterized by XRD, FESEM and HRTEM analysis. The SAED and XRD analyses exhibited the cubic structure with d hkl   =  2.2 Å, 1.9 Å and 1.38 Å. The antibacterial and antifungal activities of the dendrimer stabilized core@shell nanoparticles (DSCSNPs) were tested against the pathogens Bacillus subtilis, Proteus mirabilis, Candida albicans and Aspergillus nigir from which it is identified that the dendrimer stabilized core shell nanoparticles with silver ions at the shell (Co@AgCl) shows effectively high activity against the tested pathogen following the other core@shell nanoparticles viz Ag@TiO2 and Co@TiO2.

  3. The complex of PAMAM-OH dendrimer with Angiotensin (1-7) prevented the disuse-induced skeletal muscle atrophy in mice.

    Science.gov (United States)

    Márquez-Miranda, Valeria; Abrigo, Johanna; Rivera, Juan Carlos; Araya-Durán, Ingrid; Aravena, Javier; Simon, Felipe; Pacheco, Nicolás; González-Nilo, Fernando Danilo; Cabello-Verrugio, Claudio

    2017-01-01

    Angiotensin (1-7) (Ang-(1-7)) is a bioactive heptapeptide with a short half-life and has beneficial effects in several tissues - among them, skeletal muscle - by preventing muscle atrophy. Dendrimers are promising vehicles for the protection and transport of numerous bioactive molecules. This work explored the use of a neutral, non-cytotoxic hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimer as an Ang-(1-7) carrier. Bioinformatics analysis showed that the Ang-(1-7)-binding capacity of the dendrimer presented a 2:1 molar ratio. Molecular dynamics simulation analysis revealed the capacity of neutral PAMAM-OH to protect Ang-(1-7) and form stable complexes. The peptide coverage ability of the dendrimer was between ~50% and 65%. Furthermore, an electrophoretic mobility shift assay demonstrated that neutral PAMAM-OH effectively bonded peptides. Experimental results showed that the Ang-(1-7)/PAMAM-OH complex, but not Ang-(1-7) alone, had an anti-atrophic effect when administered intraperitoneally, as evaluated by muscle strength, fiber diameter, myofibrillar protein levels, and atrogin-1 and MuRF-1 expressions. The results of the Ang-(1-7)/PAMAM-OH complex being intraperitoneally injected were similar to the results obtained when Ang-(1-7) was systemically administered through mini-osmotic pumps. Together, the results suggest that Ang-(1-7) can be protected for PAMAM-OH when this complex is intraperitoneally injected. Therefore, the Ang-(1-7)/PAMAM-OH complex is an efficient delivery method for Ang-(1-7), since it improves the anti-atrophic activity of this peptide in skeletal muscle.

  4. The HER2-binding affibody molecule (Z(HER2∶342₂ increases radiosensitivity in SKBR-3 cells.

    Directory of Open Access Journals (Sweden)

    Lina Ekerljung

    Full Text Available We have previously shown that the HER2-specific affibody molecule (Z(HER2∶342₂ inhibits proliferation of SKBR-3 cells. Here, we continue to investigate its biological effects in vitro by studying receptor dimerization and clonogenic survival following irradiation. We found that (Z(HER2∶342₂ sensitizes the HER2-overexpressing cell line SKBR-3 to ionizing radiation. The survival after exposure to (Z(HER2∶342₂ and 8 Gy (S(8Gy 0.006 was decreased by a factor four compared to the untreated (S(8Gy 0.023. The low HER2-expressing cell line MCF-7 was more radiosensitive than SKBR-3 but did not respond to (Z(HER2∶342₂. Treatment by (Z(HER2∶342₂ strongly increased the levels of dimerized and phosphorylated HER2 even after 5 minutes of stimulation. The monomeric Z(HER2∶342 does not seem to be able to induce receptor phosphorylation and dimerization or sensitize cells to irradiation.

  5. Host-guest chemistry of dendrimer-drug complexes. 4. An in-depth look into the binding/encapsulation of guanosine monophosphate by dendrimers.

    Science.gov (United States)

    Hu, Jingjing; Fang, Min; Cheng, Yiyun; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen

    2010-06-03

    In the present study, we investigated the host-guest chemistry of dendrimer/guanosine monophosphate (GMP) and present an in-depth look into the binding/encapsulation of GMP by dendrimers using NMR studies. (1)H NMR spectra showed a significant downfield shift of methylene protons in the outmost layer of the G5 dendrimer, indicating the formation of ion pairs between cationic amine groups of dendrimer and anionic phosphate groups of GMP. Chemical shift titration results showed that the binding constant between G5 dendrimer and GMP is 17,400 M(-1) and each G5 dendrimer has 107 binding sites. The binding of GMP to dendrimers prevents its aggregation in aqueous solutions and thereby enhances its stability. Nuclear Overhauser effect measurements indicated that a GMP binding and encapsulation balance occurs on the surface and in the interior of dendrimer. The binding/encapsulation transitions can be easily tailored by altering the surface and interior charge densities of the dendrimer. All these findings provide a new insight into the host-guest chemistry of dendrimer/guest complexes and may play important roles in the study of dendrimer/DNA aggregates by a "bottom-up" strategy.

  6. Dendrimers in drug research

    DEFF Research Database (Denmark)

    Boas, Ulrik; Heegaard, Peter M. H.

    2004-01-01

    and in vivo cytotoxicity, as well as biopermeability, biostability and immunogenicity. The review deals with numerous applications of dendrimers as tools for efficient multivalent presentation of biological ligands in biospecific recognition, inhibition and targeting. Dendrimers may be used as drugs...... for antibacterial and antiviral treatment and have found use as antitumor agents. The review highlights the use of dendrimers as drug or gene delivery devices in e.g. anticancer therapy, and the design of different host-guest binding motifs directed towards medical applications is described. Other specific examples...

  7. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    Directory of Open Access Journals (Sweden)

    L. Fernández

    2011-12-01

    Full Text Available The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazol-2-yl carbamate, albendazole (ABZ using polyamidoamine (PAMAM dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3, with hydroxyl terminal groups (G3OH and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5, were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by ¹H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups.

  8. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, L.; Sigal, E.; Santo, M., E-mail: msanto@exa.unrc.edu.ar [Departamento de Fisica, Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto (Argentina); Otero, L.; Silber, J. J. [Departamento de Quimica. Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Rio Cuarto (Argentina)

    2011-10-15

    The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazole-2-yl) carbamate, albendazole (ABZ) using polyamidoamine (PAMAM) dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3), with hydroxyl terminal groups (G3OH) and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5), were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by {sup 1}H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups. (author)

  9. Peptide Dendrimer/Lipid Hybrid Systems Are Efficient DNA Transfection Reagents: Structure–Activity Relationships Highlight the Role of Charge Distribution Across Dendrimer Generations

    Science.gov (United States)

    2013-01-01

    Efficient DNA delivery into cells is the prerequisite of the genetic manipulation of organisms in molecular and cellular biology as well as, ultimately, in nonviral gene therapy. Current reagents, however, are relatively inefficient, and structure–activity relationships to guide their improvement are hard to come by. We now explore peptide dendrimers as a new type of transfection reagent and provide a quantitative framework for their evaluation. A collection of dendrimers with cationic and hydrophobic amino acid motifs (such as KK, KA, KH, KL, and LL) distributed across three dendrimer generations was synthesized by a solid-phase protocol that provides ready access to dendrimers in milligram quantities. In conjunction with a lipid component (DOTMA/DOPE), the best reagent, G1,2,3-KL ((LysLeu)8(LysLysLeu)4(LysLysLeu)2LysGlySerCys-NH2), improves transfection by 6–10-fold over commercial reagents under their respective optimal conditions. Emerging structure–activity relationships show that dendrimers with cationic and hydrophobic residues distributed in each generation are transfecting most efficiently. The trigenerational dendritic structure has an advantage over a linear analogue worth up to an order of magnitude. The success of placing the decisive cationic charge patterns in inner shells rather than previously on the surface of macromolecules suggests that this class of dendrimers significantly differs from existing transfection reagents. In the future, this platform may be tuned further and coupled to cell-targeting moieties to enhance transfection and cell specificity. PMID:23682947

  10. Transepithelial Transport of PAMAM Dendrimers Across Isolated Human Intestinal Tissue.

    Science.gov (United States)

    Hubbard, Dallin; Enda, Michael; Bond, Tanner; Moghaddam, Seyyed Pouya Hadipour; Conarton, Josh; Scaife, Courtney; Volckmann, Eric; Ghandehari, Hamidreza

    2015-11-02

    Poly(amido amine) (PAMAM) dendrimers have shown transepithelial transport across intestinal epithelial barrier in rats and across Caco-2 cell monolayers. Caco-2 models innately lack mucous barriers, and rat isolated intestinal tissue has been shown to overestimate human permeability. This study is the first report of transport of PAMAM dendrimers across isolated human intestinal epithelium. It was observed that FITC labeled G4-NH2 and G3.5-COOH PAMAM dendrimers at 1 mM concentration do not have a statistically higher permeability compared to free FITC controls in isolated human jejunum and colonic tissues. Mannitol permeability was increased at 10 mM concentrations of G3.5-COOH and G4-NH2 dendrimers. Significant histological changes in human colonic and jejunal tissues were observed at G3.5-COOH and G4-NH2 concentrations of 10 mM implying that dose limiting toxicity may occur at similar concentrations in vivo. The permeability through human isolated intestinal tissue in this study was compared to previous rat and Caco-2 permeability data. This study implicates that PAMAM dendrimer oral drug delivery may be feasible, but it may be limited to highly potent drugs.

  11. White organic light emitting diodes based on fluorene-carbazole dendrimers

    International Nuclear Information System (INIS)

    Usluer, Özlem; Demic, Serafettin; Kus, Mahmut; Özel, Faruk; Serdar Sariciftci, Niyazi

    2014-01-01

    In this paper, we report on theProd. Type: FTP fabrication and characterization of blue and white light emitting devices based on two fluorene-carbazole containing dendrimers and para-sexiphenyl (6P) oligomers. Blue light emitting diodes were fabricated using 9′,9″-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (OFC-G2) and 9′,9″-(9,9′-spirobi[fluorene]-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (SBFC-G2) dendrimers as a hole transport and emissive layer (EML) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as an electron transport layer. White light emitting diodes were fabricated using 6P and these two dendrimers as an EML. OLED device with the structure of ITO/PEDOT:PSS (50 nm)/OFC-G2 (40 nm)/6P (20 nm)/LiF:Al (0.5:100 nm) shows maximum luminance of nearly 1400 cd/m 2 and a Commission Internationale de l'Eclairage chromaticity coordinates of (0.27, 0.30) at 12 V. -- Highlights: • White organic light emitting diodes have been fabricated using two fluorene-carbazole dendrimers and para-sexiphenyl (6P) oligomers. • When only these two dendrimers are used as EML, OLED devices are emitted blue light. • The emission colors of OLED devices change from blue to white when 6P is coated on dendrimer films

  12. Upbeat nystagmus in anti-Ma2 encephalitis.

    Science.gov (United States)

    Garcia-Reitboeck, Pablo; Thompson, Graham; Johns, Paul; Al Wahab, Yasir; Omer, Salah; Griffin, Colette

    2014-02-01

    Anti-Ma2 encephalitis is a paraneoplastic disorder characterised by brainstem and/or limbic involvement. Eye movement abnormalities can occur in this condition, often with confusion or somnolence. We describe a patient with progressive oscillopsia (with upbeat nystagmus) and unsteadiness, followed by acute pancreatitis. She did not respond to immunomodulatory treatment and subsequently died of complications related to pancreatitis and sepsis. There was no tumour identified at autopsy, but the anti-Ma2 antibodies in her serum and the discovery of a brainstem-predominant inflammatory infiltrate at autopsy strongly suggest a paraneoplastic disorder. Our case illustrates that upbeat nystagmus can be a predominant feature in anti-Ma2 encephalitis; clinicians should consider testing for anti-Ma2 antibodies in patients with upbeat nystagmus of unknown cause.

  13. Curcumin-albumin conjugates as an effective anti-cancer agent with immunomodulatory properties.

    Science.gov (United States)

    Aravind, S R; Krishnan, Lissy K

    2016-05-01

    Curcumin (diferuloylmethane) is an active ingredient in turmeric (Curcuma longa) with anti-inflammatory, antioxidant, chemopreventive, chemosensitization, and radiosensitization properties. Conjugation of curcumin (Curc) to albumin (Alb) has been found to increase the aqueous solubility of the drug. The current study aimed to prove the safe use of the Curc-Alb conjugate in animals and to demonstrate that it retains drug action both in vitro and in vivo. Dalton's lymphoma ascites (DLA) cell viability was inhibited by the Curc-Alb conjugate in a dose dependent manner in vitro, as evidenced by the MTT assay. Administration of up to 11.4 mg of conjugated curcumin per kg body weight to healthy animals was non-toxic both in terms of lethality and weight loss. Histological analysis of vital organs (kidney, liver and spleen) also did not show toxic effects. Favorable immuno-modulatory activity was observed after continuous administration of sub-acute doses of the conjugate which caused increase in total leukocyte count, platelet count, and viable cell count in bone marrow, and enhanced proliferation of lymphocyte in vitro upon culture. In vivo studies in the DLA tumor model in mice demonstrated that conjugated drug induces tumor reduction and prevention. Significant tumor reduction was observed when the Curc-Alb conjugate was administered intraperitoneally in DLA-induced mice after 1 day (prevention therapy) and 7 days (reduction therapy) of tumor induction. There was significant reduction in both tumor volume and tumor cell numbers in the treated animals as well as a marked increase in their mean survival time and percent increase in life span. The effect was greater when the conjugate was administered soon after inducing the tumor as compared to when treatment was started after allowing tumor to grow for 7 days. Thus, the results of the present study suggest that curcumin albumin conjugate has immunomodulatory and tumor growth inhibition properties. The study postulates

  14. The extracellular domain of Her2 in serum as a biomarker of breast cancer.

    Science.gov (United States)

    Perrier, Alexandre; Gligorov, Joseph; Lefèvre, Guillaume; Boissan, Mathieu

    2018-02-28

    Breast cancer is a major health problem worldwide. In ~15% of breast cancers, the epidermal growth factor receptor HER2, a transmembrane protein, is overexpressed. This HER2 overexpression is associated with an aggressive form of the disease and a poor clinical prognosis. The extracellular domain (ECD) of HER2 is released into the blood by a proteolytic mechanism known as "ECD shedding". This proteolytic shedding leaves a constitutively active truncated receptor in the membrane that is 10-100-fold more oncogenic than the full-length receptor and promotes the growth and survival of cancer cells. Shedding of the HER2 ECD is increased during metastasis: whereas 15% of primary breast cancer patients have elevated levels of serum HER2 ECD (sHER2 ECD), the levels reach 45% in patients with metastatic disease. Thus, sHER2 ECD has been proposed as a promising biomarker for cancer recurrence and for monitoring the disease status of patients overexpressing HER2. Nevertheless, in 2016, the American Society of Clinical Oncology advises clinicians not to use soluble HER2 levels to guide their choice of adjuvant therapy for patients with HER2-positive breast cancer, because the evidence was considered not strong enough. Currently, biomarkers such as carcinoembryonic antigen and cancer antigen 15-3 are widely used to monitor metastatic breast cancer disease even if the level of evidence of clinical impact of this monitoring is poor. In this article, we review the evidence that sHER2 ECD might be used in some situations as a biomarker for breast cancer. Although this serum biomarker will not replace the direct measurement of tumor HER2 status for diagnosis of early-stage tumors; it might be especially useful in metastatic disease for prognosis, as an indicator of cancer progression and of therapy response, particularly to anti-HER2 therapies. Owing to these data, sHER2 ECD should be considered as a promising biomarker to detect cancer recurrence and metastasis.

  15. Synthesis and NMR characterization of dendrimers based on 2, 2-bis-(hydroxymethyl-propanoic acid (bis-HMPA containing peripheral amino acid residues for gene transfection

    Directory of Open Access Journals (Sweden)

    Silvana Alfei

    2017-08-01

    Full Text Available Dendrimers, the emerging man made, highly branched, star-shaped macromolecules with nanometer-scale dimensions are well known for their well defined and high controlled architecture, their versatility and high functionality and are of eminent interest in nanomedical applications such as drug delivery, gene transfection, and imaging. In this paper, versatile protocols for the synthesis of polyester-based, hydrolysable, polycationic dendrimers have been setup. A fourth generation dendrimer equipped with 48 peripheral hydroxyl groups was prepared from 2,2-bis(hydroxymethylpropanoic acid and was used for grafting BOC-amino acids or as “hypercores” on which dendrons functionalized with BOC-amino acids were attached. A library of 15 polycationic homo- and hetero-dendrimers in the form of hydrochloride was obtained. Their structures and composition were confirmed by NMR analysis and by experimental molecular weight computed by volumetric titration. Their buffer capacity and results obtained from cytotoxicity assays and tests of binding with both pDNA and siRNA were very satisfactory.

  16. Tailoring the dendrimer core for efficient gene delivery.

    Science.gov (United States)

    Hu, Jingjing; Hu, Ke; Cheng, Yiyun

    2016-04-15

    Dendrimers have been widely used as non-viral gene vectors due to well-defined chemical structures, high density of cationic charges and ease of surface modification. Although a large number of studies have reported the important roles of dendrimer architecture, component, generation and surface functionality in gene delivery, the effect of dendrimer core on this issue still remains unclear. Recent literatures suggest that a slight alternation in dendrimer core has a profound effect in the transfection efficacy and biocompatibility. In this review, we will discuss the transfection mechanism of dendrimers with different types of cores in respect of flexibility, hydrophobicity and functionality. We hope to open a possibility of designing efficient dendrimers for gene delivery by choosing a proper dendrimer core. As a branch of researches on dendrimers and dendritic polymers, the design of biocompatible and high efficient polymeric gene carriers has attracted increasing attentions during these years. Although the effect of dendrimer generation, species, architecture and surface functionality on gene delivery have been widely reported, the effect of dendrimer core on this issue still remains unclear. Recent literatures suggest that a minor variation on the dendrimer core has a profound effect in the transfection efficacy and biocompatibility. This critical review summarized the dendrimers with different types of cores and discussed the transfection mechanism with particular focus on the flexibility, hydrophobicity, and functionality. It is hoped to provide a new insight to design efficient and safe dendrimer-based gene vectors by choosing a proper core. To the best of our knowledge, this is the first review on the effect of dendrimer core on gene delivery. The findings obtained in this filed are of central importance in the design of efficient polymeric gene vectors. This article will appeal a wide readership such as physical chemist, dendrimer chemist, biological

  17. Phosphorus dendrimers for nanomedicine.

    Science.gov (United States)

    Caminade, Anne-Marie

    2017-08-31

    From biomaterials to imaging, and from drug delivery to drugs by themselves, phosphorus-containing dendrimers offer a large palette of biological properties, depending essentially on their types of terminal functions. The most salient examples of phosphorus dendrimers used for the elaboration of bio-chips and of supports for cell cultures, for imaging biological events, and for carrying and delivering drugs or biomacromolecules are presented in this feature article. Several phosphorus dendrimers can be considered also as drugs per se (by themselves) in particular to fight against cancers, neurodegenerative diseases, and inflammation, both in vitro and in vivo. Toxicity assays are also reported.

  18. Regulatory activity of azabisphosphonate-capped dendrimers on human CD4+ T cell proliferation enhances ex-vivo expansion of NK cells from PBMCs for immunotherapy

    Directory of Open Access Journals (Sweden)

    Caminade Anne-Marie

    2009-09-01

    Full Text Available Abstract Background Adoptive cell therapy with allogenic NK cells constitutes a promising approach for the treatment of certain malignancies. Such strategies are currently limited by the requirement of an efficient protocol for NK cell expansion. We have developed a method using synthetic nanosized phosphonate-capped dendrimers allowing such expansion. We are showing here that this is due to a specific inhibitory activity towards CD4+ T cell which could lead to further medical applications of this dendrimer. Methods Mononuclear cells from human peripheral blood were used to investigate the immunomodulatory effects of nanosized phosphonate-capped dendrimers on interleukin-2 driven CD4+T cell expansion. Proliferation status was investigated using flow cytometry analysis of CFSE diluti