RESUMEN
Lineage plasticity of prostate cancer is associated with resistance to androgen receptor (AR) pathway inhibition (ARPI) and supported by a reactive tumor microenvironment. Here we show that changes in chondroitin sulfate (CS), a major glycosaminoglycan component of the tumor cell glycocalyx and extracellular matrix, is AR-regulated and promotes the adaptive progression of castration-resistant prostate cancer (CRPC) after ARPI. AR directly represses transcription of the 4-O-sulfotransferase gene CHST11 under basal androgen conditions, maintaining steady-state CS in prostate adenocarcinomas. When AR signaling is inhibited by ARPI or lost during progression to non-AR-driven CRPC as a consequence of lineage plasticity, CHST11 expression is unleashed, leading to elevated 4-O-sulfated chondroitin levels. Inhibition of the tumor cell CS glycocalyx delays CRPC progression, and impairs growth and motility of prostate cancer after ARPI. Thus, a reactive CS glycocalyx supports adaptive survival and treatment resistance after ARPI, representing a therapeutic opportunity in patients with advanced prostate cancer.
Asunto(s)
Neoplasias de la Próstata Resistentes a la Castración , Andrógenos , Sulfatos de Condroitina , Glicocálix/metabolismo , Humanos , Masculino , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Transducción de Señal , Microambiente TumoralRESUMEN
Recent biochemical, biophysical, and genetic studies have shown that heparan sulfate, a major component of the cellular glycocalyx, participates in infection of SARS-CoV-2 by facilitating the so-called open conformation of the spike protein, which is required for binding to ACE2. This review highlights the involvement of heparan sulfate in the SARS-CoV-2 infection cycle and argues that there is a high degree of coordination between host cell heparan sulfate and asparagine-linked glycans on the spike in enabling ACE2 binding and subsequent infection. The discovery that spike protein binding and infection depends on both viral and host glycans provides insights into the evolution, spread and potential therapies for SARS-CoV-2 and its variants.
Asunto(s)
COVID-19 , Enzima Convertidora de Angiotensina 2 , Asparagina/metabolismo , Sitios de Unión , Heparitina Sulfato , Humanos , Unión Proteica , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
Placental malaria infection is mediated by the binding of the malarial VAR2CSA protein to the placental glycosaminoglycan, chondroitin sulfate. Recombinant subfragments of VAR2CSA (rVAR2) have also been shown to bind specifically and with high affinity to cancer cells and tissues, suggesting the presence of a shared type of oncofetal chondroitin sulfate (ofCS) in the placenta and in tumors. However, the exact structure of ofCS and what determines the selective tropism of VAR2CSA remains poorly understood. In this study, ofCS was purified by affinity chromatography using rVAR2 and subjected to detailed structural analysis. We found high levels of N-acetylgalactosamine 4-O-sulfation (â¼80-85%) in placenta- and tumor-derived ofCS. This level of 4-O-sulfation was also found in other tissues that do not support parasite sequestration, suggesting that VAR2CSA tropism is not exclusively determined by placenta- and tumor-specific sulfation. Here, we show that both placenta and tumors contain significantly more chondroitin sulfate moieties of higher molecular weight than other tissues. In line with this, CHPF and CHPF2, which encode proteins required for chondroitin polymerization, are significantly upregulated in most cancer types. CRISPR/Cas9 targeting of CHPF and CHPF2 in tumor cells reduced the average molecular weight of cell-surface chondroitin sulfate and resulted in a marked reduction of rVAR2 binding. Finally, utilizing a cell-based glycocalyx model, we showed that rVAR2 binding correlates with the length of the chondroitin sulfate chains in the cellular glycocalyx. These data demonstrate that the total amount and cellular accessibility of chondroitin sulfate chains impact rVAR2 binding and thus malaria infection.
Asunto(s)
Antígenos de Protozoos/metabolismo , Sulfatos de Condroitina/metabolismo , Glicocálix/metabolismo , Malaria Falciparum/metabolismo , Plasmodium falciparum/metabolismo , Proteínas Protozoarias/metabolismo , Antígenos de Protozoos/química , Antígenos de Protozoos/genética , Sulfatos de Condroitina/química , Sulfatos de Condroitina/genética , Femenino , Glicocálix/química , Glicocálix/genética , Células HEK293 , Células HeLa , Humanos , Malaria Falciparum/genética , N-Acetilgalactosaminiltransferasas/genética , N-Acetilgalactosaminiltransferasas/metabolismo , Placenta/metabolismo , Plasmodium falciparum/genética , Embarazo , Proteínas Protozoarias/química , Proteínas Protozoarias/genéticaRESUMEN
Placental malaria can have severe consequences for both mother and child and effective vaccines are lacking. Parasite-infected red blood cells sequester in the placenta through interaction between parasite-expressed protein VAR2CSA and the glycosaminoglycan chondroitin sulfate A (CS) abundantly present in the intervillous space. Here, we report cryo-EM structures of the VAR2CSA ectodomain at up to 3.1 Å resolution revealing an overall V-shaped architecture and a complex domain organization. Notably, the surface displays a single significantly electropositive patch, compatible with binding of negatively charged CS. Using molecular docking and molecular dynamics simulations as well as comparative hydroxyl radical protein foot-printing of VAR2CSA in complex with placental CS, we identify the CS-binding groove, intersecting with the positively charged patch of the central VAR2CSA structure. We identify distinctive conserved structural features upholding the macro-molecular domain complex and CS binding capacity of VAR2CSA as well as divergent elements possibly allowing immune escape at or near the CS binding site. These observations will support rational design of second-generation placental malaria vaccines.
Asunto(s)
Antígenos de Protozoos/química , Antígenos de Protozoos/metabolismo , Sulfatos de Condroitina/metabolismo , Malaria Falciparum/complicaciones , Placenta/parasitología , Complicaciones Parasitarias del Embarazo/metabolismo , Complicaciones Parasitarias del Embarazo/parasitología , Secuencia de Aminoácidos , Antígenos de Protozoos/genética , Microscopía por Crioelectrón , Femenino , Humanos , Evasión Inmune , Malaria Falciparum/metabolismo , Malaria Falciparum/parasitología , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Mutagénesis , Placenta/inmunología , Placenta/metabolismo , Plasmodium falciparum/genética , Plasmodium falciparum/inmunología , Plasmodium falciparum/patogenicidad , Embarazo , Unión Proteica , Dominios ProteicosRESUMEN
We identify the prolyl-tRNA synthetase (PRS) inhibitor halofuginone 1 , a compound in clinical trials for anti-fibrotic and anti-inflammatory applications 2 , as a potent inhibitor of SARS-CoV-2 infection and replication. The interaction of SARS-CoV-2 spike protein with cell surface heparan sulfate (HS) promotes viral entry 3 . We find that halofuginone reduces HS biosynthesis, thereby reducing spike protein binding, SARS-CoV-2 pseudotyped virus, and authentic SARS-CoV-2 infection. Halofuginone also potently suppresses SARS-CoV-2 replication post-entry and is 1,000-fold more potent than Remdesivir 4 . Inhibition of HS biosynthesis and SARS-CoV-2 infection depends on specific inhibition of PRS, possibly due to translational suppression of proline-rich proteins. We find that pp1a and pp1ab polyproteins of SARS-CoV-2, as well as several HS proteoglycans, are proline-rich, which may make them particularly vulnerable to halofuginone's translational suppression. Halofuginone is orally bioavailable, has been evaluated in a phase I clinical trial in humans and distributes to SARS-CoV-2 target organs, including the lung, making it a near-term clinical trial candidate for the treatment of COVID-19.
RESUMEN
Chondroitin sulfate (CS)and dermatan sulfate (DS) are negatively charged polysaccharides found abundantly in animal tissue and have been extensively described to play key roles in health and disease. The most common method to analyze their structure is by digestion into disaccharides with bacterial chondroitinases, followed by chromatography and/or mass spectrometry. While studying the structure of oncofetal CS, we noted a large variation in the activity and specificity of commercially available chondroitinases. Here studied the kinetics of the enzymes and used high-performance liquid chromatography-mass spectrometry to determine the di- and oligosaccharide products resulting from the digestion of commercially available bovine CS A, shark CS C and porcine DS, focusing on chondroitinases ABC, AC and B from different vendors. Application of a standardized assay setup demonstrated large variations in the enzyme-specific activity compared to the values provided by vendors, large variation in enzyme specific activity of similar enzymes from different vendors and differences in the extent of cleavage of the substrates and the generated products. The high variability of different chondroitinases highlights the importance of testing enzyme activity and monitoring product formation in assessing the content and composition of chondroitin and DSs in cells and tissues.
Asunto(s)
Condroitinasas y Condroitín Liasas/metabolismo , Disacáridos/metabolismo , Animales , Conformación de Carbohidratos , Bovinos , Sulfatos de Condroitina/metabolismo , Dermatán Sulfato/metabolismo , Especificidad por Sustrato , PorcinosRESUMEN
Circulating tumor cells (CTCs) are accessible by liquid biopsies via an easy blood draw. They represent not only the primary tumor site, but also potential metastatic lesions, and could thus be an attractive supplement for cancer diagnostics. However, the analysis of rare CTCs in billions of normal blood cells is still technically challenging and novel specific CTC markers are needed. The formation of metastasis is a complex process supported by numerous molecular alterations, and thus novel CTC markers might be found by focusing on this process. One example of this is specific changes in the cancer cell glycocalyx, which is a network on the cell surface composed of carbohydrate structures. Proteoglycans are important glycocalyx components and consist of a protein core and covalently attached long glycosaminoglycan chains. A few CTC assays have already utilized proteoglycans for both enrichment and analysis of CTCs. Nonetheless, the biological function of proteoglycans on clinical CTCs has not been studied in detail so far. Therefore, the present review describes proteoglycan functions during the metastatic cascade to highlight their importance to CTCs. We also outline current approaches for CTC assays based on targeting proteoglycans by their protein cores or their glycosaminoglycan chains. Lastly, we briefly discuss important technical aspects, which should be considered for studying proteoglycans.
RESUMEN
We show that SARS-CoV-2 spike protein interacts with both cellular heparan sulfate and angiotensin-converting enzyme 2 (ACE2) through its receptor-binding domain (RBD). Docking studies suggest a heparin/heparan sulfate-binding site adjacent to the ACE2-binding site. Both ACE2 and heparin can bind independently to spike protein in vitro, and a ternary complex can be generated using heparin as a scaffold. Electron micrographs of spike protein suggests that heparin enhances the open conformation of the RBD that binds ACE2. On cells, spike protein binding depends on both heparan sulfate and ACE2. Unfractionated heparin, non-anticoagulant heparin, heparin lyases, and lung heparan sulfate potently block spike protein binding and/or infection by pseudotyped virus and authentic SARS-CoV-2 virus. We suggest a model in which viral attachment and infection involves heparan sulfate-dependent enhancement of binding to ACE2. Manipulation of heparan sulfate or inhibition of viral adhesion by exogenous heparin presents new therapeutic opportunities.
Asunto(s)
Betacoronavirus/fisiología , Heparitina Sulfato/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Secuencia de Aminoácidos , Enzima Convertidora de Angiotensina 2 , Betacoronavirus/aislamiento & purificación , Sitios de Unión , COVID-19 , Línea Celular , Infecciones por Coronavirus/patología , Infecciones por Coronavirus/virología , Heparina/química , Heparina/metabolismo , Heparitina Sulfato/química , Humanos , Riñón/metabolismo , Pulmón/metabolismo , Simulación de Dinámica Molecular , Pandemias , Peptidil-Dipeptidasa A/química , Neumonía Viral/patología , Neumonía Viral/virología , Unión Proteica , Dominios Proteicos , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Internalización del VirusRESUMEN
We show that SARS-CoV-2 spike protein interacts with cell surface heparan sulfate and angiotensin converting enzyme 2 (ACE2) through its Receptor Binding Domain. Docking studies suggest a putative heparin/heparan sulfate-binding site adjacent to the domain that binds to ACE2. In vitro, binding of ACE2 and heparin to spike protein ectodomains occurs independently and a ternary complex can be generated using heparin as a template. Contrary to studies with purified components, spike protein binding to heparan sulfate and ACE2 on cells occurs codependently. Unfractionated heparin, non-anticoagulant heparin, treatment with heparin lyases, and purified lung heparan sulfate potently block spike protein binding and infection by spike protein-pseudotyped virus and SARS-CoV-2 virus. These findings support a model for SARS-CoV-2 infection in which viral attachment and infection involves formation of a complex between heparan sulfate and ACE2. Manipulation of heparan sulfate or inhibition of viral adhesion by exogenous heparin may represent new therapeutic opportunities.
RESUMEN
Chondroitin sulfate (CS) is the placental receptor for the VAR2CSA malaria protein, expressed at the surface of infected erythrocytes during Plasmodium falciparum infection. Infected cells adhere to syncytiotrophoblasts or get trapped within the intervillous space by binding to a determinant in a 4-O-sulfated CS chains. However, the exact structure of these glycan sequences remains unclear. VAR2CSA-reactive CS is also expressed by tumor cells, making it an attractive target for cancer diagnosis and therapeutics. The identities of the proteoglycans carrying these modifications in placental and cancer tissues remain poorly characterized. This information is clinically relevant since presentation of the glycan chains may be mediated by novel core proteins or by a limited subset of established proteoglycans. To address this question, VAR2CSA-binding proteoglycans were affinity-purified from the human placenta, tumor tissues and cancer cells and analyzed through a specialized glycoproteomics workflow. We show that VAR2CSA-reactive CS chains associate with a heterogenous group of proteoglycans, including novel core proteins. Additionally, this work demonstrates how affinity purification in combination with glycoproteomics analysis can facilitate the characterization of CSPGs with distinct CS epitopes. A similar workflow can be applied to investigate the interaction of CSPGs with other CS binding lectins as well.
Asunto(s)
Antígenos de Protozoos/metabolismo , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Placenta/metabolismo , Proteómica , Neoplasias de la Vejiga Urinaria/metabolismo , Antígenos de Protozoos/química , Proteoglicanos Tipo Condroitín Sulfato/química , Cromatografía de Afinidad , Femenino , Humanos , Placenta/química , Embarazo , Neoplasias de la Vejiga Urinaria/patologíaRESUMEN
Glycosaminoglycans (GAGs) are essential polysaccharides in normal physiology and disease. However, understanding of the contribution of specific GAG structures to specific biological functions is limited, largely because of the great structural heterogeneity among GAGs themselves, as well as technical limitations in the structural characterization and chemical synthesis of GAGs. Here we describe a cell-based method to produce and display distinct GAGs with a broad repertoire of modifications, a library we refer to as the GAGOme. By using precise gene editing, we engineered a large panel of Chinese hamster ovary cells with knockout or knock-in of the genes encoding most of the enzymes involved in GAG biosynthesis, to generate a library of isogenic cell lines that differentially display distinct GAG features. We show that this library can be used for cell-based binding assays, recombinant expression of proteoglycans with distinct GAG structures, and production of distinct GAG chains on metabolic primers that may be used for the assembly of GAG glycan microarrays.