16 research outputs found

    Deciphering the Multifaceted Relationship between Oncolytic Viruses and Natural Killer Cells

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    Despite active research in virotherapy, this apparently safe modality has not achieved widespread success. The immune response to viral infection appears to be an essential factor that determines the efficacy of oncolytic viral therapy. The challenge is determining whether the viral-elicited immune response is a hindrance or a tool for viral treatment. NK cells are a key component of innate immunity that mediates antiviral immunity while also coordinating tumor clearance. Various reports have suggested that the NK response to oncolytic viral therapy is a critical factor in premature viral clearance while also mediating downstream antitumor immunity. As a result, particular attention should be given to the NK cell response to various oncolytic viral vectors and how their antiviral properties can be suppressed while maintaining tumor clearance. In this review we discuss the current literature on the NK response to oncolytic viral infection and how future studies clarify this intricate response

    TGF-β signaling and its targeting for glioma treatment

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    Abstract: Transforming growth factor-beta (TGF-β) is a pleiotropic cytokine, secreted by a variety of cells including immune cells, tumor cells, and stromal cells. TGF-β signaling is dysregulated in cancer patients, and this aberrant signaling at least in part contributes to initiation and progression of many cancers including glioma. The dysregulated signaling components provide molecular targets for the treatment of glioma. In this article, we review TGF-β signaling and its targeting in glioma

    Reshaping the tumor microenvironment with oncolytic viruses, positive regulation of the immune synapse, and blockade of the immunosuppressive oncometabolic circuitry

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    Background Oncolytic viruses are considered part of immunotherapy and have shown promise in preclinical experiments and clinical trials. Results from these studies have suggested that tumor microenvironment remodeling is required to achieve an effective response in solid tumors. Here, we assess the extent to which targeting specific mechanisms underlying the immunosuppressive tumor microenvironment optimizes viroimmunotherapy.Methods We used RNA-seq analyses to analyze the transcriptome, and validated the results using Q-PCR, flow cytometry, and immunofluorescence. Viral activity was analyzed by replication assays and viral titration. Kyn and Trp metabolite levels were quantified using liquid chromatography–mass spectrometry. Aryl hydrocarbon receptor (AhR) activation was analyzed by examination of promoter activity. Therapeutic efficacy was assessed by tumor histopathology and survival in syngeneic murine models of gliomas, including Indoleamine 2,3-dioxygenase (IDO)-/- mice. Flow cytometry was used for immunophenotyping and quantification of cell populations. Immune activation was examined in co-cultures of immune and cancer cells. T-cell depletion was used to identify the role played by specific cell populations. Rechallenge experiments were performed to identify the development of anti-tumor memory.Results Bulk RNA-seq analyses showed the activation of the immunosuppressive IDO-kynurenine-AhR circuitry in response to Delta-24-RGDOX infection of tumors. To overcome the effect of this pivotal pathway, we combined Delta-24-RGDOX with clinically relevant IDO inhibitors. The combination therapy increased the frequency of CD8+ T cells and decreased the rate of myeloid-derived suppressor cell and immunosupressive Treg tumor populations in animal models of solid tumors. Functional studies demonstrated that IDO-blockade-dependent activation of immune cells against tumor antigens could be reversed by the oncometabolite kynurenine. The concurrent targeting of the effectors and suppressors of the tumor immune landscape significantly prolonged the survival in animal models of orthotopic gliomas.Conclusions Our data identified for the first time the in vivo role of IDO-dependent immunosuppressive pathways in the resistance of solid tumors to oncolytic adenoviruses. Specifically, the IDO-Kyn-AhR activity was responsible for the resurface of local immunosuppression and resistance to therapy, which was ablated through IDO inhibition. Our data indicate that combined molecular and immune therapy may improve outcomes in human gliomas and other cancers treated with virotherapy
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