RESUMO
The cell surface of Toxoplasma gondii is rich in glycoconjugates which hold diverse and vital functions in the lytic cycle of this obligate intracellular parasite. Additionally, the cyst wall of bradyzoites, that shields the persistent form responsible for chronic infection from the immune system, is heavily glycosylated. Formation of glycoconjugates relies on activated sugar nucleotides, such as uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). The glucosamine-phosphate-N-acetyltransferase (GNA1) generates N-acetylglucosamine-6-phosphate critical to produce UDP-GlcNAc. Here, we demonstrate that downregulation of T. gondii GNA1 results in a severe reduction of UDP-GlcNAc and a concomitant drop in glycosylphosphatidylinositols (GPIs), leading to impairment of the parasite's ability to invade and replicate in the host cell. Surprisingly, attempts to rescue this defect through exogenous GlcNAc supplementation fail to completely restore these vital functions. In depth metabolomic analyses elucidate diverse causes underlying the failed rescue: utilization of GlcNAc is inefficient under glucose-replete conditions and fails to restore UDP-GlcNAc levels in GNA1-depleted parasites. In contrast, GlcNAc-supplementation under glucose-deplete conditions fully restores UDP-GlcNAc levels but fails to rescue the defects associated with GNA1 depletion. Our results underscore the importance of glucosamine-6-phosphate acetylation in governing T. gondii replication and invasion and highlight the potential of the evolutionary divergent GNA1 in Apicomplexa as a target for the development of much-needed new therapeutic strategies.
Assuntos
Acetilglucosamina , Glucose-6-Fosfato , Toxoplasma , Toxoplasma/metabolismo , Glucose-6-Fosfato/metabolismo , Glucose-6-Fosfato/análogos & derivados , Acetilglucosamina/metabolismo , Acetilação , Animais , Glucosamina 6-Fosfato N-Acetiltransferase/metabolismo , Humanos , Glucosamina/metabolismo , Glucosamina/análogos & derivados , Camundongos , Toxoplasmose/metabolismo , Toxoplasmose/parasitologia , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genéticaRESUMO
Over two decades, most cancer vaccines failed clinical development. Key factors may be the lack of efficient priming with tumor-specific antigens and strong immunostimulatory signals. MVX-ONCO-1, a personalized cell-based cancer immunotherapy, addresses these critical steps utilizing clinical-grade material to replicate a successful combination seen in experimental models: inactivated patient's own tumor cells, providing the widest cancer-specific antigen repertoire and a standardized, sustained, local delivery over days of a potent adjuvant achieved by encapsulated cell technology. We conducted an open-label, single-arm, first-in-human phase I study with MVX-ONCO-1 in patients with advanced refractory solid cancer. MVX-ONCO-1 comprises irradiated autologous tumor cells coimplanted with two macrocapsules containing genetically engineered cells producing granulocyte-macrophage colony-stimulating factor. Patients received six immunizations over 9 weeks without maintenance therapy. Primary objectives were safety, tolerability, and feasibility, whereas secondary objectives focused on efficacy and immune monitoring. Data from 34 patients demonstrated safety and feasibility with minor issues. Adverse events included one serious adverse event possibly related to investigational medicinal product and two moderate-related adverse events. More than 50% of the patients with advanced and mainly nonimmunogenic tumors showed clinical benefits, including partial responses, stable diseases, and prolonged survival. In recurrent/metastatic head and neck squamous cell carcinoma, one patient achieved a partial response, whereas another survived for more than 7 years without anticancer therapy for over 5 years. MVX-ONCO-1 is safe, well tolerated, and beneficial across several tumor types. Ongoing phase IIa trials target patients with advanced recurrent/metastatic head and neck squamous cell carcinoma after initial systemic therapy. SIGNIFICANCE: This first-in-human phase I study introduces a groundbreaking approach to personalized cancer immunotherapy, addressing limitations of traditional strategies. By combining autologous irradiated tumor cells as a source of patient-specific antigens and utilizing encapsulated cell technology for localized, sustained delivery of granulocyte-macrophage colony-stimulating factor as an adjuvant, the study shows a very good safety and feasibility profile. This innovative approach holds the promise of addressing tumor heterogeneity by taking advantage of each patient's antigenic repertoire.
Assuntos
Vacinas Anticâncer , Imunoterapia Ativa , Neoplasias , Medicina de Precisão , Humanos , Pessoa de Meia-Idade , Masculino , Feminino , Neoplasias/terapia , Neoplasias/imunologia , Vacinas Anticâncer/uso terapêutico , Vacinas Anticâncer/administração & dosagem , Idoso , Medicina de Precisão/métodos , Imunoterapia Ativa/métodos , Adulto , Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêuticoRESUMO
Encapsulated cell therapy holds a great potential to deliver sustained levels of highly potent therapeutic proteins to patients and improve chronic disease management. A versatile encapsulation device that is biocompatible, scalable, and easy to administer, retrieve, or replace has yet to be validated for clinical applications. Here, we report on a cargo-agnostic, macroencapsulation device with optimized features for protein delivery. It is compatible with adherent and suspension cells, and can be administered and retrieved without burdensome surgical procedures. We characterized its biocompatibility and showed that different cell lines producing different therapeutic proteins can be combined in the device. We demonstrated the ability of cytokine-secreting cells encapsulated in our device and implanted in human skin to mobilize and activate antigen-presenting cells, which could potentially serve as an effective adjuvant strategy in cancer immunization therapies. We believe that our device may contribute to cell therapies for cancer, metabolic disorders, and protein-deficient diseases.
RESUMO
[This corrects the article DOI: 10.1016/j.omtm.2022.07.017.].
RESUMO
Despite many promising results obtained in previous preclinical studies, the clinical development of encapsulated cell technology (ECT) for the delivery of therapeutic proteins from macrocapsules is still limited, mainly due to the lack of an allogeneic cell line compatible with therapeutic application in humans. In our work, we generated an immortalized human myoblast cell line specifically tailored for macroencapsulation. In the present report, we characterized the immortalized myoblasts and described the engineering process required for the delivery of functional therapeutic proteins including a cytokine, monoclonal antibodies and a viral antigen. We observed that, when encapsulated, the novel myoblast cell line can be efficiently frozen, stored, and thawed, which limits the challenge imposed by the manufacture and supply of encapsulated cell-based therapeutic products. Our results suggest that this versatile allogeneic cell line represents the next step toward a broader development and therapeutic use of ECT.