RESUMO
The anomeric aminooxy GM3 trisaccharide cancer antigen (Neu5Acα2,3Galß1,4Glcß-ONH2) has been chemically synthesized using a linear glycosylation approach. The key step involves a highly α(2,3)-stereoselective sialylation to a galactose acceptor. The Neu5Acα2,3Gal intermediate was functionalized as a donor for a [2 + 1] glycosylation, including a glucose acceptor that featured an O-succinimidyl group on the reducing end as an aminooxy precursor. The fully deprotected anomeric aminooxy GM3 trisaccharide was then conjugated to the immunologically relevant zwitterionic polysaccharide PS A1 via an oxime link.
Assuntos
Oximas , Polissacarídeos , Galactose , GlicosilaçãoRESUMO
The Thomsen-Friedenreich (TF) antigen is a key target for the development of anticancer vaccines, and this ongoing challenge remains relevant due to the poor immunogenicity of the TF antigen. To overcome this challenge, we adopted a bivalent conjugate design which introduced both the TF antigen and the Thomsen-nouveau (Tn) antigen onto the immunologically relevant polysaccharide A1 (PS A1). The immunological results in C57BL/6 mice revealed that the bivalent, Tn-TF-PS A1 conjugate increased the immune response towards the TF antigen as compared to the monovalent TF-PS A1. This phenomenon was first observed with enzyme-linked immunosorbent assay (ELISA) where the bivalent conjugate generated high titers of IgG antibodies where the monovalent conjugate generated an exclusive IgM response. Fluorescence-activated cell sorting (FACS) analysis also revealed increased binding events to the tumor cell lines MCF-7 and OVCAR-5, which are consistent with the enhanced tumor cell lysis observed in a complement dependent cytotoxicity (CDC) assay. The cytokine profile generated by the bivalent construct revealed increased pro-inflammatory cytokines IL-17 and IFN-γ. This increase in cytokine concentration was matched with an increase in cytokine producing cells as observed by ELISpot. We hypothesized the mechanisms for this phenomenon to involve the macrophage galactose N-acetylgalactosamine specific lectin 2 (MGL2). This hypothesis was supported by using biotinylated probes and recombinant MGL2 to measure carbohydrate-protein interactions.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Carboidratos/imunologia , Imunidade , Imunoconjugados/imunologia , Animais , Anticorpos/metabolismo , Especificidade de Anticorpos/imunologia , Biotinilação , Carboidratos/síntese química , Carboidratos/química , Linhagem Celular Tumoral , Proteínas do Sistema Complemento/metabolismo , Citocinas/metabolismo , Citotoxicidade Imunológica , Humanos , Imunoconjugados/química , Lectinas Tipo C/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/metabolismo , Baço/imunologiaRESUMO
The construction of a tumor-associated carbohydrate antigen-zwitterionic polysaccharide conjugate, Thomsen-nouveau-polysaccharide A1 (Tn-PS A1, where Tn = D-GalpNAc), has led to the development of a carbohydrate binding monoclonal antibody named Kt-IgM-8. Kt-IgM-8 was produced via hybridoma from Tn-PS A1 hyperimmunized Jackson Laboratory C57BL/6 mice, splenocytes and the murine myeloma cell line Sp2/0Ag14 with subsequent cloning on methyl cellulose semi-solid media. This in-house generated monoclonal antibody negates binding influenced from peptides, proteins, and lipids and preferentially binds monovalent Tn antigen as noted by ELISA, FACS, and glycan array technologies. Kt-IgM-8 demonstrated in vitro and in vivo tumor killing against the Michigan Cancer Foundation breast cell line 7 (MCF-7). In vitro tumor killing was observed using an LDH assay that measured antibody-induced complement-dependent cytotoxicity and these results were validated in an in vivo passive immunotherapy approach using an MCF-7 cell line-derived xenograft model. Kt-IgM-8 is effective in killing tumor cells at 30% cytotoxicity, and furthermore, it demonstrated approximately 40% reduction in tumor growth in the MCF-7 model.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Antineoplásicos Imunológicos/farmacologia , Neoplasias da Mama/terapia , Imunoglobulina M/imunologia , Imunotoxinas/farmacologia , Animais , Neoplasias da Mama/imunologia , Humanos , Imunotoxinas/imunologia , Células MCF-7 , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Polissacarídeos/imunologia , Polissacarídeos/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The synthesis of spiro[indoline-3,2'-pyrrole]-2,5'(1'H)-diones and spiro[indoline-3,2'-pyrrolidine]-2,5'-diones, via a post-Ugi-domino transamidation/cyclization sequential process, has been achieved in three sequential steps utilizing a one-pot reaction protocol. The variation in carboxylic acid substrates allows for the generation of new chiral racemic quaternary carbon centers under basic conditions providing molecular diversity and a small library of spirocyclic oxindoles.
RESUMO
Sialyl Thomsen-nouveau (STn) is a tumor-associated carbohydrate antigen (TACA) that is overexpressed in a variety of carcinomas such as breast, ovarian, and colon cancer. In normal tissue, STn is not detectable, which is critical for opportunities in developing cancer immunotherapies. A novel, entirely carbohydrate, semisynthetic STn-polysaccharide (PS) A1 conjugate was prepared and evaluated in C57BL/6 mice. STn-PS A1 was combined with commercially available monophosphoryl lipid A-based adjuvant, and after immunization, ELISA indicated a strong immune response for inducing anti-STn IgM/IgG antibodies. The specificity of these antibodies was concomitantly investigated using FACS analysis, and the results indicated excellent cell surface binding events to STn-expressing cancer cell lines MCF-7 and OVCAR-5. An INF-γ ELISpot assay was conducted to further confirm a robust cellular immunity invoked by STn-PS A1. Most importantly, the raised antibodies conferred complement-dependent cellular cytotoxicity against MCF-7 and OVCAR-5 cells.
Assuntos
Antígenos Glicosídicos Associados a Tumores/química , Antígenos Glicosídicos Associados a Tumores/imunologia , Polissacarídeos/química , Animais , Técnicas de Química Sintética , Humanos , Células MCF-7 , Camundongos , Oximas/químicaRESUMO
A highly efficient and stereocontrolled synthesis of an aminooxy derivative of the tetrasaccharide repeating unit of a rhamnose-rich polysaccharide isolated from the cell envelop of bovine mastitis Streptococcus dysgalactiae 2023 is reported for the first time. The synthesis was accomplished utilizing a stereoselective and convergent [2 + 2] glycosylation strategy inclusive of a disaccharide Schmidt donor and an inclusive rhamnose disaccharide acceptor. The synthetic aminooxy tetrasaccharide was conjugated to T-cell stimulating immunogen PS A1 from Bacteroides fragilis ATCC 25285/NCTC 9343 via a physiologically stable oxime linkage to furnish the first semisynthetic bacterial-based immunogen construct targeting S. dysgalactiae 2023. The synthetic tetrasaccharide was assembled in 19 steps with a â¼5.0% overall yield.
Assuntos
Polissacarídeos/química , Polissacarídeos/imunologia , Streptococcus/química , Streptococcus/imunologia , Vacinas Conjugadas/química , Vacinas Conjugadas/imunologia , Animais , Bacteroides fragilis/imunologia , Sequência de Carboidratos , Bovinos , Feminino , Glicosilação , Mastite Bovina/imunologia , Mastite Bovina/microbiologia , Oximas/química , Estereoisomerismo , Linfócitos T/imunologiaRESUMO
PS B, a naturally occurring CD4(+) T-cell simulating zwitterionic polysaccharide from Bacteroides fragilis ATCC 25285/NCTC 9343, was conjugated with aminooxy Thomsen Friedenreich (TF or T) [α-d-Gal-(1,3)-ß-d-GalNAc-ONH2] tumor antigen. Immunization in Jax C57BL/6, followed by ELISA revealed IgM and IgG antibody TF specificity. FACS data noted preferential binding to TF-laced MCF-7 cells but not to HCT-116 cells.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Polissacarídeos/imunologia , Animais , Reações Antígeno-Anticorpo , Antígenos Glicosídicos Associados a Tumores/química , Bacteroides fragilis/química , Configuração de Carboidratos , Ensaio de Imunoadsorção Enzimática , Células HCT116 , Humanos , Imunoglobulina G/química , Imunoglobulina G/imunologia , Imunoglobulina M/química , Imunoglobulina M/imunologia , Células MCF-7 , Camundongos , Camundongos Endogâmicos C57BL , Polissacarídeos/químicaRESUMO
Herbicide (±)-thaxtomin A has been synthesized in a one-pot process with a 32% isolated yield. A multicomponent coupling reaction was utilized to prepare in situ a dipeptide precursor which then sequentially underwent an alkaline mediated keto-amide cyclization to provide the target molecule. Adjustment of diastereoselectivity was achieved using microwave-induced irradiation. The approach incorporates atom economy and reaction efficiency and allows for facile library development.
Assuntos
Produtos Biológicos/síntese química , Herbicidas/síntese química , Indóis/síntese química , Piperazinas/síntese química , Produtos Biológicos/química , Ciclização , Herbicidas/química , Indóis/química , Estrutura Molecular , Piperazinas/química , EstereoisomerismoRESUMO
The α-aminooxy derivative of the Thomsen-Friedenriech tumor associated carbohydrate antigen has been synthesized in 11 steps utilizing a D-GalN3 acceptor carrying a pre-installed α-N-hydroxysuccinimidyl moiety. The natural α linkage was prepared in high selectivity employing a suitably protected D-GalN3-thioglycoside donor with N-hydroxysuccinimide. With access to α-TF-ONH2, the preparation of the TF-PS A1 vaccine candidate ensued smoothly through oxime bond formation.
Assuntos
Dissacarídeos/síntese química , Polissacarídeos/química , Adjuvantes Imunológicos/química , Dissacarídeos/química , Polissacarídeos/imunologiaRESUMO
This Special Issue of Pharmaceuticals presents one review and six original articles that are demonstrative of the importance of glycomimetics and glycoconjugates as privileged groups of carbohydrate-based molecules in the search for and development of bioactive substances for therapeutic/pharmaceutical purposes [...].
RESUMO
The tumor-associated carbohydrate antigen/hapten Thomsen-nouveau (Tn; a-D-GalpNAc-ONH2) was conjugated to a zwitterionic capsular polysaccharide, PS A1, from commensal anaerobe Bacteroides fragilis ATCC 25285/NCTC 9343 for the development of an entirely carbohydrate cancer vaccine construct and probed for immunogenicity. This communication discloses that murine anti-Tn IgG3 antibodies both bind to and recognize human tumor cells that display the Tn hapten. Furthermore, the sera from immunization of mice with Tn-PS A1 contain cytokine interleukin 17 (IL-17A), which is known to possess anti-tumor function and represents a striking difference to an IL-2, and IL-6 profile obtained with anti-PS A1 sera.
Assuntos
Antígenos de Neoplasias/imunologia , Antígenos Glicosídicos Associados a Tumores/imunologia , Bacteroides fragilis/imunologia , Neoplasias da Mama/imunologia , Vacinas Anticâncer/imunologia , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Carboidratos/química , Carboidratos/imunologia , Linhagem Celular Tumoral , Feminino , Humanos , Soros Imunes/imunologia , Imunidade , Imunização , Imunoglobulina G/metabolismo , Interleucina-17/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Polissacarídeos Bacterianos/administração & dosagem , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/imunologiaRESUMO
A rapid, cascade reaction process has been developed to access biologically validated spiro-2,5-diketopiperazines. The facile and environmentally benign method capitalizes on commercially available starting reagents for a sequential Ugi/6-exo-trig aza-Michael reaction, water as a solvent, and microwave irradiation without any extraneous additives.
Assuntos
Dicetopiperazinas/síntese química , Compostos de Espiro/síntese química , Catálise , Cristalografia por Raios X , Dicetopiperazinas/química , Indicadores e Reagentes/química , Micro-Ondas , Modelos Moleculares , Estrutura Molecular , Solventes/química , Compostos de Espiro/química , Estereoisomerismo , Água/químicaRESUMO
With a view to reducing the notorious complexity and irreproducibility of glycosylation reactions, 12 guidelines for the choice of concentration, temperature, and counterions are adumbrated.
RESUMO
An anticancer, entirely carbohydrate conjugate, Globo H-polysaccharide A1 (Globo H-PS A1), was chemically prepared and immunologically evaluated in C57BL/6 mice. Tumor associated carbohydrate antigen Globo H hexasaccharide was synthesized in an overall 7.8% yield employing a convergent [3 + 3] strategy that revealed an anomeric aminooxy group used for conjugation to oxidized PS A1 via an oxime linkage. Globo H-PS A1, formulated with adjuvants monophosphoryl lipid A and TiterMax® Gold. After immunization an antigen specific immune response was observed in ELISA with anti-Globo H IgG/IgM antibodies. Specificity of the corresponding antibodies was determined by FACS showing cell surface binding to Globo H-positive cancer cell lines MCF-7 and OVCAR-5. The anti-Globo H antibodies also exhibited complement-dependent cellular cytotoxicity against MCF-7 and OVCAR-5 cells.
RESUMO
An entirely carbohydrate-based immunogen consisting of a zwitterionic polysaccharide (ZPS) PS A1 and the well-known tumor antigen Tn has been designed, synthesized, and studied for immunological effects. The PS A1 motif was included to act as an MHCII elicitor for a T-cell-dependent immune response with increased immunogenicity against tumor-associated carbohydrate antigens, providing an alternative to carrier proteins. Through the use of C57BL/6 mice, it has been shown that chemical modification of PS A1 does not alter the recognition sequence responsible for an MHCII-mediated, T-cell-dependent immune response. The Tn-PS A1 conjugate construct confers specificity toward the Tn antigen alone, and specific carbohydrate immunoglobulins, namely, IgG3, are generated from intraperitoneal immunizations with or without adjuvant. The properties of the vaccine candidate are attributed to a site-specific linking strategy that incurs significant incorporation of Tn antigen.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Imunoconjugados/imunologia , Oligossacarídeos/imunologia , Vacinas Sintéticas/imunologia , Animais , Antígenos Glicosídicos Associados a Tumores/química , Bovinos , Haptenos/imunologia , Antígenos de Histocompatibilidade/imunologia , Imunoconjugados/química , Imunoterapia , Camundongos , Neoplasias/imunologia , Neoplasias/terapia , Oligossacarídeos/química , Vacinas Sintéticas/químicaRESUMO
Cancer cells of diverse origins express extracellular tumor-specific carbohydrate antigens (TACAs) because of aberrant glycosylation. Overexpressed TACAs on the surface of tumor cells are considered biomarkers for cancer detection and have always been prioritized for the development of novel carbohydrate-based anti-cancer vaccines. In recent years, progress has been made in developing synthetic, carbohydrate-based antitumor vaccines to improve immune responses associated with targeting these specific antigens. Tumor cells also exhaust more energy for proliferation than normal cells, by consuming excessive amounts of glucose via overexpressed sugar binding or transporting receptors located in the cellular membrane. Furthermore, inspired by the Warburg effect, glycoconjugation strategies of anticancer drugs have gained considerable attention from the scientific community. This review highlights a small cohort of recent efforts which have been made in carbohydrate-based cancer treatments, including vaccine design and the development of glycoconjugate prodrugs, glycosidase inhibiting iminosugars, and early cancer diagnosis.
RESUMO
The tetrasaccharide repeating unit of zwitterionic polysaccharide A1 (PS A1) from Bacteroides fragilis ATCC 25285/NCTC 9343 has been synthesized using a linear glycosylation approach. One key step includes an α(1,4)-stereoselective [2 + 1] glycosylation of a 2,4,6-trideoxy-2-acetamido-4-amino-d-Gal p (AAT) donor with a poorly reactive axial C4-OH disaccharide acceptor. Mild acid-mediated deacetylation and a challenging [3 + 1] glycosylation are also highlighted. The strategy is inclusive of a single-pot, three-step deprotection affording PS A1 with alternating charges on adjacent monosaccharide units.
Assuntos
Bacteroides fragilis/química , Monossacarídeos/química , Oligossacarídeos/química , Polissacarídeos Bacterianos/química , Polissacarídeos/síntese química , Sequência de Carboidratos , Catálise , Galactose/química , Glicosilação , Metais/químicaRESUMO
Small molecule diversity can be achieved in a single synthetic operation from bifunctional substrates in the absence of additives and under the influence of microwaves with complete control of pathway selectivity. The preliminary Ugi four-component coupling products give rise to three structurally distinct scaffolds that are dependent on solvent effects and sterics. 2,5-Diketopiperazines (Type A), 2-azaspiro[4.5]deca-6,9-diene-3,8-diones (Type B), and thiophene-derived Diels-Alder tricyclic lactams (Type C) predominate in this reaction cascade.
RESUMO
Mycothiol cysteine ligase (MshC) is a key enzyme in the mycothiol (MSH) biosynthesis and a promising target for developing new anti-mycobacterial compounds. Herein, we report on the synthesis of substrate analogues, as potential inhibitors, for the MshC enzyme. The target molecules were synthesized employing a Schmidt glycosylation strategy using an enantiomerically pure inositol acceptor and 2-deoxy trichloroacetimidate glycosyl donors with glycosylation yields greater than 70% and overall yields >5%. The inositol acceptor was obtained via chiral resolution of (±)-myo-inositol.