Statins act as transient type I interferon inhibitors to enable the antitumor activity of modified vaccinia Ankara viral vectors

Abstract

BackgroundModified vaccinia virus Ankara (MVA) are genetically engineered non-replicating viral vectors. Intratumoral administration of MVA induces a cyclic GMP-AMP synthase-mediated type I interferon (IFN) response and the production of high levels of the transgenes engineered into the viral genome such as tumor antigens to construct cancer vaccines. Although type I IFNs are essential for establishing CD8-mediated antitumor responses, this cytokine family may also give rise to immunosuppressive mechanisms.MethodsIn vitro assays were performed to evaluate the activity of simvastatin and atorvastatin on type I IFN signaling and on antigen presentation. Surface levels of IFN α/β receptor 1, endocytosis of bovine serum albumin-fluorescein 5 (6)-isothiocyanate, signal transducer and activator of transcription (STAT) phosphorylation, and real-time PCR of IFN-stimulated genes were assessed in the murine fibroblast cell line L929. In vivo experiments were performed to characterize the effect of simvastatin on the MVA-induced innate immune response and on the antitumor effect of MVA-based antitumor vaccines in B16 melanoma expressing ovalbumin (OVA) and Lewis lung carcinoma (LLC)-OVA tumor models. RNAseq analysis, depleting monoclonal antibodies, and flow cytometry were used to evaluate the MVA-mediated immune response.ResultsIn this work, we identified commonly prescribed statins as potent IFNα pharmacological inhibitors due to their ability to reduce surface expression levels of IFN-α/β receptor 1 and to reduce clathrin-mediated endocytosis. Simvastatin and atorvastatin efficiently abrogated for 8 hours the transcriptomic response to IFNα and enhanced the number of dendritic cells presenting an OVA-derived peptide bound to major histocompatibility complex (MHC) class I. In vivo, intraperitoneal or intramuscular administration of simvastatin reduced the inflammatory response mediated by peritumoral administration of MVA and enhanced the antitumor activity of MVA encoding tumor-associated antigens. The synergistic antitumor effects critically depend on CD8+ cells, whereas they were markedly improved by depletion of CD4+ lymphocytes, T regulatory cells, or NK cells. Either MVA-OVA alone or combined with simvastatin augmented B cells, CD4+ lymphocytes, CD8+ lymphocytes, and tumor-specific CD8+ in the tumor-draining lymph nodes. However, only the treatment combination increased the numbers of these lymphocyte populations in the tumor microenvironment and in the spleen.ConclusionIn conclusion, blockade of IFNα functions by simvastatin markedly enhances lymphocyte infiltration and the antitumor activity of MVA, prompting a feasible drug repurposing.

Statin drugs enhance responses to immune checkpoint blockade in head and neck cancer models

“…Emerging studies suggest that manipulation of cholesterol in the serum, tumor microenvironment, or peripheral lymphoid tissue may enhance some aspects of antitumor immunity. [17][18][19][20][21][22][23][24][25] Proposed mechanisms based on preclinical studies are numerous. These include enhanced activation of T cells or dendritic cells, decreased T cell exhaustion, improving antigen presentation, ER stress, elevating immunogenic cell death, and transient inhibition of type I interferon.…”

“…These include enhanced activation of T cells or dendritic cells, decreased T cell exhaustion, improving antigen presentation, ER stress, elevating immunogenic cell death, and transient inhibition of type I interferon. [17][18][19][20][21][22][23][24][25] However, conclusions from many of these studies were drawn from use of supraphysiological (micromolar) 26 27 doses and non-oral routes of administration. In the present study, we used a highthroughput, ex vivo T cell killing platform to compare the activity of all seven available statin drugs at a range of clinically relevant (nanomolar) 26 27 concentrations.…”

Modulating cholesterol-rich lipid rafts to disrupt influenza A virus infection

“…IFNLRs are present on mucosal epithelial cells and recognize IFN-λ, which is typically released from myeloid cells, epithelial cells, and DCs ( Figure 1 ) ( 107 ). Reduction of cholesterol with MβCD is known to disrupt localization and assembly of IFNGR at lipid rafts ( 106 ), while depletion of cholesterol by simvastatin and atorvastatin prevents IFNAR1 expression and endocytosis ( Figure 1 ; Table 3 ) ( 105 ).…”

“…IFITM3 prevents the transport of cholesterol from ER to late endosomes, thus affecting fusion with the IAV envelope, and also blocks the formation of fusion pores to disrupt the release of vRNPs ( Figure 1 ; Table 2 ) ( 65 , 70 – 72 ). Several recent studies have shown that statins can inhibit IFN signaling and activity ( 87 , 105 ), likely through the inhibition of IRF-3 and JAK/STAT signaling in macrophages ( 105 ), and the impact of this on the host antiviral response is worthy of further investigation. Interestingly, a study of gammaherpesvirus infection showed that type I interferon counters the antiviral effects of statins derived through the reduction of cholesterol, and therefore the reported inhibition of IFN activity by statins may be expected to enhance their cholesterol-dependent antiviral activity ( 163 ).…”

“…It has been shown that treatment with anti-IFN-γ significantly reduced lung pathology, inflammatory cell infiltration, and mortality of mouse models infected by IAV, indicating that IFN-γ is a key molecule involved in the development of a cytokine storm. Statins are known to inhibit the production of several inflammatory cytokines ( 87 , 102 , 105 ) and may serve to modulate the cytotoxic activity of CD8 + T cells during IAV clearance. Unlike CD8 + T cells, CD4 + T cells are activated by antigens presented on MHCII molecules, followed by the binding of CD40L to CD40 on APCs such as DCs ( 191 ).…”