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Bioconjugate Chemistry

Huicong Zhang, Zhisu Sun, Kuanglei Wang, Na Li, Hongxiang Chen, Xiao Tan, Lingxiao Li, Zhonggui He, Jin Sun
We report a new type of amide bond-bearing cathepsin B-sensitive gemcitabine (GEM) prodrugs, capable of in situ covalently targeting circulating albumin and then making a hitchhike to the tumor. Specially, less plasma-enzyme deactivation, long plasma half-life, independence on nucleoside transporters, outstanding tumor targeting and site-specific drug release are achieved and such these multifunctional advantages contribute to the dramatically increased in vivo antitumor efficacy.
May 18, 2018: Bioconjugate Chemistry
Shasha Sun, Yingyu Huang, Chen Zhou, Sishan Chen, Mengxiao Yu, Jinbin Liu, Jie Zheng
Fundamental understanding of how the hydrophobicity impacts cellular interactions of engineered nanoparticles is critical to their future success in healthcare. Herein, we report that inserting hydrophobic octanethiol onto the surface of zwitterionic luminescent glutathione coated gold nanoparticles (GS-AuNPs) of 2 nm enhanced their affinity to the cellular membrane and increased cellular uptake kinetics by more than one order of magnitude, rather than inducing the accumulation of the AuNPs in the bilayer core or enhancing their passive diffusion...
May 18, 2018: Bioconjugate Chemistry
Delong Zeng, Shulin Deng, Chengcheng Sang, Jianfu Zhao Zhao, Tianfeng Chen
Chemical drug design based on the biochemical characteristics of cancer cells has become an important strategy for discovery of targeted therapies for personalized cancer medicine. Herein, cancer targeting RGD peptide has been covalently conjugated to selenadiazole derivative (RGD-SeD) to improve its cancer selectivity. The RGD decoration significantly enhances the anticancer efficacy of RGD-SeD in αVβ3 integrin-overexpressing HepG2 liver cancer cells, but not in normal liver cells. Cellular uptake assay and fluorescent imaging confirmed the selectivity of RGD-SeD to integrin overexpressing cancer cells...
May 17, 2018: Bioconjugate Chemistry
Jiang Liu, Sachin Asaram Ingale, Frank Seela
The α-anomers of 8-aza-2'-deoxyguanosine (αGd*) and 2'-deoxyguanosine (αGd) were site-specifically incorporated in 12-mer duplexes opposite to the four canonical DNA constituents dA, dG, dT and dC. Oligodeoxyribonucleotides containing αGd* display significant fluorescence at slightly elevated pH (8.0). Oligodeoxyribonucleotides incorporating β-anomeric 8-aza-2'-deoxyguanosine (Gd*) and canonical dG were studied for comparison. For αGd* synthesis, an efficient purification of anomeric 8-azaguanine nucleosides was developed on the basis of protected intermediates and a new αGd* phosphoramidite was prepared...
May 17, 2018: Bioconjugate Chemistry
Michelle W Lee, Ernest Y Lee, Gerard C L Wong
A common bioengineering strategy to add function to a given molecule is by conjugation of a new moiety onto that molecule. Adding multiple functions in this way becomes increasingly challenging and leads to composite molecules with larger molecular weights. In this review, we attempt to gain a new perspective by looking at this problem in reverse, by examining nature's strategies of multiplexing different functions into the same pleiotropic molecule using emerging analysis techniques such as machine learning...
May 17, 2018: Bioconjugate Chemistry
Ryo Nishihara, Emi Hoshino, Yoshiki Kakudate, Satoshi Kishigami, Naoko Iwasawa, Shin-Ichi Sasaki, Takahiro Nakajima, Moritoshi Sato, Shigeru Nishiyama, Daniel Citterio, Koji Suzuki, Sung Bae Kim
Native coelenterazine (nCTZ) is a common substrate to most marine luciferases and photoproteins. In this study, nine novel dye- and azide-conjugated CTZ analogues were synthesized by conjugating a series of fluorescent dyes or an azide group to the C-2 or C-6 position of the nCTZ backbone to obtain bulkiness-driven substrate specificity and potential chemiluminescence/bioluminescence resonance energy transfer (C/BRET). The investigation on the optical properties revealed that azide-conjugated CTZs emit greatly biased bioluminescence to ALucs and ca...
May 16, 2018: Bioconjugate Chemistry
Jeremy D King, Yuelong Ma, Yi-Chui Kuo, Krzysztof P Bzymek, Leah H Goodstein, Kassondra Meyer, Roger E Moore, Desiree Crow, David Colcher, Gagandeep Singh, David A Horne, John C Williams
The high specificity and favorable pharmacological properties of monoclonal antibodies (mAbs) have prompted significant interest in re-engineering this class of molecules to add novel functionalities for enhanced therapeutic and diagnostic potential. Here, we used the high affinity, meditope-Fab interaction to template and drive the rapid, efficient, and stable site-specific formation of a disulfide bond. We demonstrate that this template-catalyzed strategy provides a consistent and reproducible means to conjugate fluorescent dyes, cytotoxins, or "click" chemistry handles to meditope-enabled mAbs (memAbs) and memFabs...
May 15, 2018: Bioconjugate Chemistry
Saya Otake, Kou Okuro, Davide Bochicchio, Giovanni M Pavan, Takuzo Aida
FL NBD-BAMPEG2k bearing a nitrobenzoxadiazole (NBD) unit and an oleyl terminus conjugated via a poly(ethylene glycol) (PEG) spacer ( Mn = 2,000), was designed to fluorescently label cell membranes by docking its hydrophobic oleyl terminus. During laser scanning microscopy in a minimal essential medium (MEM), human hepatocellular carcinoma Hep3B cells labelled with FL NBD-BAMPEG2k appeared to undergo optoporation at their plasma membrane. We confirmed this unprecedented possibility by a series of cellular uptake experiments using negatively charged and therefore membrane-impermeable quantum dots (QDs; Dh = 4...
May 15, 2018: Bioconjugate Chemistry
Kei Toyama, Wataru Nomura, Takuya Kobayakawa, Hirokazu Tamamura
A cyclic decapeptide, CQTPYYMNTC (1), which mimics the dimerization arm of the EGF receptor (EGFR), was previously found to be captured into cells. We have sought to investigate the promising potential of this peptide as an intracellular delivery vehicle directed to EGFR-positive cells. The selectivity of Peptide 1 to the EGFR was confirmed by a positive correlation between the expression level of the receptor and the cellular uptake of Peptide 1 as shown by siRNA knockdown of the EGFR. The pro-apoptotic domain (PAD) peptide, ([KLAKLAK]2), has limited use due to a deficiency of cell membrane permeability resulting from cationic sequences and lack of specificity for cancer cells...
May 15, 2018: Bioconjugate Chemistry
Yi Liu, Hsuan-Chen Wu, Narendrath Bhokisham, Jinyang Li, Kai-Lin Hong, David Quan, Chen-Yu Tsao, William E Bentley, Gregory F Payne
Biology often provides the inspiration for functional soft matter, but biology can do more: it can provide the raw materials and mechanisms for hierarchical assembly. Biology uses polymers to perform various functions and biologically-derived polymers can serve as sustainable, self-assembling and high-performance materials platforms for life-science applications. Biology employs enzymes for site-specific reactions that are used to both disassemble and assemble biopolymers both to and from component parts. By exploiting protein engineering methodologies, proteins can be modified to make them more susceptible to biology's native enzymatic activities...
May 10, 2018: Bioconjugate Chemistry
Ryou Kubota, Shuang Liu, Hajime Shigemitsu, Keisuke Nakamura, Wataru Tanaka, Masato Ikeda, Itaru Hamachi
Multicomponent self-assembly is a fascinating strategy for the construction of smart soft materials. Among them, supramolecular hydrogels comprising self-sorting nanofibers have recently attracted significant attention owing to their rationally incorporated stimulus responsiveness. However, there have been limited investigations of the crucial factors that control the self-sorting phenomena. Here, we describe an imaging-based approach to evaluate the factors that control the formation of self-sorting nanofibers from peptide- and lipid-type hydrogelators...
May 9, 2018: Bioconjugate Chemistry
Md Nazir Hossen, Brennah Murphy, Lorena Garcia, Resham Bhattacharya, Priyabrata Mukherjee
Nanoparticles, the building blocks of nanotechnology, have been widely utilized in various biomedical applications, such as detection, diagnosis, imaging, and therapy. However, another emerging, albeit under represented, area is the employment of nanoparticles as tools to understand cellular processes (e.g. oxidative stress-induced signaling cascades). Such investigations have enormous potential to characterize a disease from a different perspective and unravel some new features that otherwise would have remained a mystery...
May 9, 2018: Bioconjugate Chemistry
Christian Toonstra, Lisa Wu, Chao Li, Denong Wang, Lai-Xi Wang
High mannose type N-glycans are an important component of neutralizing epitopes on HIV-1 envelope glycoprotein gp120. They also serve as signals for protein folding, trafficking, and degradation in protein quality control. A number of lectins and antibodies recognize high-mannose type N-glycans, and glycan array technology has provided an avenue to probing these oligomannose-specific proteins. We describe in this paper a top-down chemoenzymatic approach to synthesizing a library of high-mannose N-glycans and related neoglycoproteins for glycan microarray analysis...
May 8, 2018: Bioconjugate Chemistry
Joseph Bteich, Mark J Ernsting, Mohammed Z Mohammed, Taira Kiyota, Trevor McKee, Mohit Trikha, Henry Lowman, Kenneth K Sokoll
Nanoparticles provide a unique opportunity to explore the benefits of selective distribution and release of cancer therapeutics at sites of disease through varying particle sizes and compositions that exploit the enhanced permeability of tumor-associated blood vessels. Though delivery of larger-as opposed to smaller and/or actively transported-molecules to the brain is prime face a challenging endeavor, we wondered whether nanoparticles could improve the therapeutic index of existing drugs for use in treating brain tumors via these vascular effects...
May 7, 2018: Bioconjugate Chemistry
Gloria Hernandez-Torres, Ernesto Enriquez Palacios, Miriam Mecha, Ana Feliu, Ainoa Rueda-Zubiaurre, Alba Angelina, Leticia Martin-Cruz, Mar Martín-Fontecha, Oscar Palomares, Carmen Guaza, Eduardo Peña-Cabrera, María L López-Rodríguez, Silvia Ortega-Gutierrez
Serotonin (5-HT) modulates key aspects of the immune system. However, its precise function and the receptors involved in the observed effects have remained elusive. Among the different serotonin receptors, 5-HT1A plays an important role in the immune system given its presence in cells involved in both the innate and the adaptive immune responses, but its actual levels of expression under different conditions have not been comprehensively studied due to the lack of suitable tools. To further clarify the role of 5-HT1A receptor in the immune system, we have developed a fluorescent small molecule probe that enables the direct study of the receptor levels in native cells...
May 7, 2018: Bioconjugate Chemistry
Bedilu Allo, Xudong Lou, Alexandre Bouzekri, Olga I Ornatsky
Mass cytometry is a highly multiplexed single-cell analysis platform that uses metal tagged reagents to identify multiple cellular biomarkers. Current metal-tagged reagent preparation employs thiol-maleimide chemistry to covalently couple maleimide-functionalized metal-chelating polymers (MCPs) with antibodies (Abs), a process that requires partial reduction of the Ab to form reactive thiol groups. However, some classes of Abs (for example, IgM) as well as biomolecules lacking cysteine residues has been challenging to label using this method...
May 7, 2018: Bioconjugate Chemistry
Liliane Massaad-Massade, Suzan Boutary, Marie Caillaud, Céline Gracia, Beatrice Parola, Soukaina Bel Gnaouiya, Barbara Stella, Silvia Arpicco, Eric Buchy, Didier Desmaêle, Patrick Couvreur, Giorgia Urbinati
The aim of the present study is to take advantage of the unique property of polyisoprenoid chains to adopt a compact molecular conformation and to use these natural and biocompatible lipids as nanocarriers of drugs to deliver siRNA. A new chemical strategy is here applied to conjugate squalene (SQ) and solanesol (SOLA) to siRNA consisting in an activated variant of the azide-alkyne Huisgen cycloaddition also known as copper-free (Cu-free) click chemistry. We conjugated siRNA against TMPRSS2-ERG, a fusion oncogene found in more than 50% of prostate cancers to SQ or SOLA...
May 4, 2018: Bioconjugate Chemistry
Laura Chambre, Aysun Degirmenci, Rana Sanyal, Amitav Sanyal
Nanogels that are amenable toward facile multi-functionalization with imaging, therapeutic and targeting agents are attractive theranostic platforms for addressing challenges in conventional diagnostics and therapy. In this work, reactive copolymers containing poly(ethylene glycol), maleimide and pendant hydroxyl groups as side chains are used to construct nanogels by employing their thermoresponsive self-assembly in aqueous media. Subsequent crosslinking of these nanosized aggregates with dithiols using thiol-maleimide chemistry yields nanogels containing maleimide, thiol and hydroxyl groups...
May 4, 2018: Bioconjugate Chemistry
Karim Rafie, Andrii Gorelik, Riccardo Trapannone, Vladimir S Borodkin, Daan M F Aalten
O-GlcNAc transferase (OGT) is an essential glycosyltransferase that installs the O-GlcNAc posttranslational modification on the nucleocytoplasmic proteome. We report the development of S-linked UDP-peptide conjugates as potent bisubstrate OGT inhibitors. These compounds were assembled in a modular fashion by photo-initiated thiol-ene conjugation of allyl-UDP and optimal acceptor peptides in which the acceptor serine was replaced with cysteine. The conjugate VTPVC(S-propyl-UDP)TA (Ki = 1.3 µM) inhibits the OGT activity in HeLa cell lysates...
May 3, 2018: Bioconjugate Chemistry
Benjamin J Umlauf, Kalie A Mix, Vanessa A Grosskopf, Ronald T Raines, Eric V Shusta
Biologics, such as antibody-drug conjugates, are becoming mainstream therapeutics. Consequently, methods to functionalize biologics without disrupting their native properties are essential for identifying, characterizing, and translating candidate biologics from the bench to clinical practice. Here, we present a method for site-specific, carboxy-terminal modification of single-chain antibody fragments (scFvs). ScFvs displayed on the surface of yeast were isolated and functionalized by combining intein-mediated expressed protein ligation (EPL) with inverse electron-demand Diels-Alder (IEDDA) cycloaddition using a styrene-tetrazine pair...
May 3, 2018: Bioconjugate Chemistry
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