Vaccine-primed CAR T-cells reject antigen-heterogenous tumors via host immunity
Ontology highlight
ABSTRACT: Chimeric Antigen Receptor (CAR) T-cell therapy effectively treats human cancer, but loss of the antigen recognized by the CAR poses a major obstacle. We found that in vivo vaccine boosting of CAR T-cells triggers engagement of the endogenous immune system to circumvent antigen-negative tumor escape. Vaccine-boosted CAR-T promoted dendritic cell (DC) recruitment to tumors, increased tumor antigen uptake by DCs, and elicited priming of endogenous anti-tumor T-cells (antigen spreading). This process was accompanied by shifts in CAR-T metabolism toward oxidative phosphorylation and was critically dependent on CAR T-derived IFN-γ. Antigen spreading induced by vaccine-boosted CAR T enabled a proportion of complete responses even when the initial tumor was 50% CAR-antigen-negative, and heterogenous tumor control was further enhanced by genetically amplifying CAR T IFN-γ expression. Thus, CAR T-cell-derived IFN-γ plays a critical role in promoting antigen spreading, and vaccine boosting provides a clinically-translatable strategy to drive such responses against solid tumors.
Project description:All nucleated mammalian cells express major histocompatibility complex (MHC) proteins that present peptides on cell surfaces for immune surveillance. These MHC-presented peptides (pMHC) can convey non-self antigens derived from pathogens or mutations to amount T-cell responses. Alterations in tumor-specific antigens – particularly mutation-bearing peptides (neoantigens) presented by MHC — can serve as potent substrates for anti-tumor immune responses. Here we employed an integrated genomic and proteomic antigen discovery strategy aimed at measuring interferon gamma (IFN-γ) induced alterations to antigen presentation, using a lymphoma cell line. IFN-γ treatment resulted in a set of differentially expressed proteins (2 % of all quantified proteins) including components of antigen presentation machinery or interferon signaling pathways. In addition, several proteasome subunits were found to be modulated, consistent with previous reports of immunoproteasome induction by IFN-γ exposure. This finding suggests that a modest proteomic response to IFN-γ could create larger alteration to cells antigen repertoires. Accordingly, by surveying immunopeptides, distinct peptide repertoires were exclusively observed in the IFN-γ induced samples. Furthermore, an additional set of presented peptides distinguished control and the IFN-γ samples by their altered relative abundances including neoantigens. Accordingly, we developed a classification system to distinguish peptides which are differentially presented due to altered expression from novel peptides resulting from changes in antigen processing. Taken together, these data demonstrate that IFN-γ can re-shape antigen repertoires by identity and by abundance. Extending this approach to models with greater clinical relevance should help develop strategies by which immunopeptide repertoires are intentionally reshaped to improve endogenous or vaccine-induced anti-tumor immune responses and potentially anti-viral immune responses.
Project description:Anti-cancer immunotherapy approaches are increasingly coveted. Chimeric antigen receptor (CAR)-T cell therapy has been shown to be an effective treatment for hematological tumors, but the treatment of solid tumors still lacks effectiveness, due to lower intra-tumor infiltration of CAR-T cells and tumor-induced immunosuppression. Macrophages represent a very large proportion of the tumor environment, participate in many aspects to tumor development and therefore represent interesting therapeutic targets. Macrophages can infiltrate solid tumor tissue and interact with almost all cellular components in the tumor microenvironment. In addition, macrophages can also promote a direct anti-tumor response by phagocyting tumor cells. We have developed macrophages expressing a CAR receptor against the HER2 antigen. The CAR receptor possesses an intracellular domain CD3ζ having homology with the protein FcεRI-γ, which once activated by the recognition antibody-antigen, induces the phagocytic activity of macrophages. 72% of macrophages express the CAR after transduction. CAR-M can specifically phagocyte HER2 coated-beads in a much more effective way than WT macrophages. We have then confirmed the capacity of CAR-M to phagocyte HER2+ cancer cell lines. Co-culture of CAR-M with breast cancer tumoroids (HER2+ or HER2-) has also been performed demonstrating their efficacy in a more complex environment. However, in the tumor microenvironment, due to their plasticity, macrophages tend to adopt an anti-inflammatory phenotype losing their anti-tumor activities. We have therefore developed a combined strategy by inhibiting two proprotein convertases, Furin and PC1/3 in CAR-M. The inhibition of furin or PC1/3 induces an increase in pro-inflammatory markers and maintains macrophage activation in the presence of cancer cells. In addition, HER2+ CAR-M with shFurin or shPC1/3 greatly increases the phagocytic activity on Her2+ beads or Her2+ tumors. These enzymes are therefore phenotypic regulators of macrophages. Our strategy is therefore based on a double activation of tumor-infiltrating macrophages. The first one consists in boosting the phagocytic activity of macrophages by having them express a CAR receptor targeting a tumor antigen. The second allows their reprogramming towards a pro- inflammatory phenotype by the inhibition of Furin and/or PC1/3 proprotein convertases
Project description:Cultured epidermal keratinocyte controls used for IFNg, TNFa and IL1 treatment. Interferon (IFN)-gamma, is a multifunctional, immunomodulatory cytokine with cell type-specific antiviral activities, particularly important in skin, where it is implicated in many diseases ranging from warts to psoriasis and cancer. Since epidermis is our first line of defence against many viruses, we investigated the molecular processes regulated by IFN-gamma in keratinocytes using DNA microarrays. We identified the IFN-gamma-regulated keratinocyte-specific genes in keratinocytes, IFN-gamma-induced tight junction proteins, presumably to deny viruses paracellular routes of infection. Furthermore, differing from published data, we find that IFN-gamma suppressed the expression of keratinocytes differentiation markers including desmosomal proteins, cornified envelope components and suprabasal cytokeratins. Inhibition of differentiation may interfere with the epidermal tropism of viruses that require differentiating cells for growth, for example, papillomaviruses. As in other cell types, IFN-gamma induced HLA, cell adhesion and proteasome proteins, facilitating leukocyte attraction and antigen-presentation by keratinocytes. IFN-gamma also induced chemokine/cytokines specific for mononuclear cells. IFN-gamma suppressed the expression of over 100 genes responsible for cell cycle, DNA replication and RNA metabolism, thereby shutting down many nuclear processes and denying viruses a healthy cell in which to replicate. Thus, uniquely in keratinocytes, IFN-gamma initiates a well-organized molecular programme boosting host antiviral defences, obstructing viral entry, suppressing cell proliferation and impeding differentiation.
Project description:Autologous anti-CD19 chimeric antigen receptor T-cell (CAR T) therapy is highly effective in relapsed/refractory large B-cell lymphoma (rrLBCL) but is associated with toxicities that delay recovery. While the biological mechanisms of cytokine release syndrome and neurotoxicity have been investigated, the pathophysiology is poorly understood for prolonged cytopenia, defined as grade ≥3 cytopenia lasting beyond 30 days after CAR T infusion. By performing single-cell RNA-sequencing analysis of bone marrow samples from healthy donors and rrLBCL patients with and without prolonged cytopenia, we identified a significantly increased frequency of clonally expanded CX3CR1hi cytotoxic T-cells, expressing high interferon (IFN)-γ and cytokine signaling gene sets, associated with prolonged cytopenia. In line with this, hematopoietic stem cells from these patients expressed IFN-γ response signatures. IFN-γ deregulates hematopoietic stem cell self-renewal and differentiation and can be targeted with thrombopoietin agonists or IFN-γ neutralizing antibodies, highlighting a potential mechanism-based approach for the treatment of CAR T-associated prolonged cytopenia.
Project description:The limited efficacy of chimeric antigen receptor (CAR) T-cell therapy for solid tumors necessitates engineering strategies that promote functional persistence in an immunosuppressive environment. Herein, we exploit c-Kit signaling, a physiological pathway associated with stemness in hematopoietic progenitor cells (T cells lose expression of c-Kit during differentiation). CAR T cells with intracellular expression—but no cell-surface receptor expression—of the c-Kit D816V mutation (KITv) have upregulated STAT phosphorylation, antigen-activation-dependent proliferation, CD28- and IL-2–independent and IFN-γ–mediated costimulation, augmenting the cytotoxicity of first-generation CAR T cells. This translates to enhanced survival, including in TGF-β–rich and low-antigen-expressing solid tumor models. KITv CAR T cells have equivalent or better in vivo efficacy than second-generation CAR T cells and are susceptible to tyrosine kinase inhibitors (safety switch). When combined with CD28 costimulation, KITv costimulation functions as a third signal, enhancing efficacy and providing a potent approach to treat solid tumors.
Project description:Chimeric antigen receptor (CAR) T cell therapy relies on the activity of a large pool of tumor-targeting cytotoxic effectors. Whether CAR T cells act autonomously or require interactions with the tumor microenvironment (TME) is unclear. Here, we report an essential crosstalk between CAR T cell subsets and the TME for tumor control. Using single-cell RNA sequencing, we revealed profound modification of the TME during CAR T cell therapy. IFN-gamma produced by CAR T cells and host-derived IL-12 not only enhanced endogenous T and NK cell activity but were also essential for sustaining CAR T cell cytotoxicity as revealed by intravital imaging. Compared to CD8+ CAR T cells, CD4+ CAR T cells were more efficient at host immune activation but less capable of tumor killing. In sum, CAR T cells are not acting alone in vivo but rely instead on a cytokine-mediated crosstalk with the TME for optimal activity. Invigorating CAR T cell interplay with the host represents an attractive strategy to prevent relapses.
Project description:The comparative resistance of some cancers including head and neck squamous cell carcinoma to checkpoint blockade is speculated to derive from the low frequency of expressed somatic mutations targeted by T cells as neoantigens. SCCVII, a spontaneously arising murine squamous carcinoma resembling human HNSCC in several key features, is likewise poorly immunogenic as irradiated tumor cells alone fail to induce protective immunity within syngeneic hosts. Justifying use of this model to identify NeoAgs, we confirm activated CD4+ and CD8+ T cells are detectable and essential for vaccine efficacy of SCC VII and polyI:C co-administration. Whole-exome sequencing tumor versus normal genome identified 39 nonsynonymous missense mutations that were synthesized into 81 representative 20-mers. NeoAg-specific CD4+ T cell IFN-γ responses were found against mutations of Pik3ca, Ctnnd1, and Otud5 while both CD4+ and CD8+ T cells produced IFN-γ when stimulated by a single Cltc mutation during in vitro recall assays. Prophylactic immunization with a mixture of all stimulatory peptides or the Cltc NeoAg alone protected hosts from subsequent tumor challenge. Further, the Cltc NeoAg, eliciting both CD4+ and CD8+ T cell responses, was also therapeutically beneficial in vivo. Anti-PD-1 combinatorial blockade resulted in synergistic tumor rejection via boosting Cltc-specific responses and increasing response diversification via epitope spreading. These data show that a functional NeoAg identification platform can be used to select immunotherapeutically relevant targets and filtration of neoepitopes that co-prime both CD4+ and CD8+ T cell responses is superior for practical intervention of poorly immunogenic tumors.
Project description:The comparative resistance of some cancers including head and neck squamous cell carcinoma to checkpoint blockade is speculated to derive from the low frequency of expressed somatic mutations targeted by T cells as neoantigens. SCCVII, a spontaneously arising murine squamous carcinoma resembling human HNSCC in several key features, is likewise poorly immunogenic as irradiated tumor cells alone fail to induce protective immunity within syngeneic hosts. Justifying use of this model to identify NeoAgs, we confirm activated CD4+ and CD8+ T cells are detectable and essential for vaccine efficacy of SCC VII and polyI:C co-administration. Whole-exome sequencing tumor versus normal genome identified 39 nonsynonymous missense mutations that were synthesized into 81 representative 20-mers. NeoAg-specific CD4+ T cell IFN-γ responses were found against mutations of Pik3ca, Ctnnd1, and Otud5 while both CD4+ and CD8+ T cells produced IFN-γ when stimulated by a single Cltc mutation during in vitro recall assays. Prophylactic immunization with a mixture of all stimulatory peptides or the Cltc NeoAg alone protected hosts from subsequent tumor challenge. Further, the Cltc NeoAg, eliciting both CD4+ and CD8+ T cell responses, was also therapeutically beneficial in vivo. Anti-PD-1 combinatorial blockade resulted in synergistic tumor rejection via boosting Cltc-specific responses and increasing response diversification via epitope spreading. These data show that a functional NeoAg identification platform can be used to select immunotherapeutically relevant targets and filtration of neoepitopes that co-prime both CD4+ and CD8+ T cell responses is superior for practical intervention of poorly immunogenic tumors.
Project description:A growing body of evidence suggests that inflammatory cytokines have a dualistic role in immunity. In this study, we sought to determine the direct effects IFN-gamma on the differentiation and maturation of human peripheral blood monocyte-derived dendritic cells (moDC). Here, we report that following differentiation of human peripheral-blood monocytes into moDCs with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4, interferon-gamma (IFN-gamma) induces moDC maturation and up-regulates the co-stimulatory markers CD80, CD86, CD95, and MHC Class I, enabling moDCs to effectively generate antigen-specific CD4+ and CD8+ T cell responses for multiple viral and tumor antigens. Interestingly, early exposure of monocytes to high concentrations of IFN-gamma promotes monocyte differentiation into macrophages, despite the presence of GM-CSF and IL-4. However, under low concentrations of IFN-gamma, monocytes continue to differentiate into dendritic cells possessing a unique gene-expression profile, resulting in impairments in subsequent maturation by IFN-gamma and an inability to generate effective antigen-specific CD4+ and CD8+ T cell responses compared to standard moDCs. Monocytes differentiated in the presence of low levels of IFN-gamma downregulate IFN-gamma receptor expression, impairing their response to an inflammatory rechallenge. These findings demonstrate the ability of IFN-gamma to impart differential programs on human moDCs which shape the antigen-specific T cell responses they induce. Timing and intensity of exposure to IFN-gamma can thus determine whether moDCs are tolerogenic or immunostimulating. Human monocyte-derived dendritic cells from 4 healthy donors were differentiated with either GM-CSF and IL-4 (n=4) or GM-CSF, IL-4, and IFN-gamma (n=4). These samples were subsequently hybridized to arrays as 4 biological repeats for each of the two treatment conditions.
Project description:Chimeric antigen receptor (CAR) T cell therapy is a powerful adoptive immunotherapy against blood cancers, but the therapeutic effect was not efficient enough on solid tumors. B cells have been reported to play a critical role in regulating memory T differentiation and cytotoxic T development. However, as of yet the influence of such B cells on CAR T cells has not been discussed. In this study, using ephrin type-A receptor 2 (EphA2) specific CAR T cells, we cultured B cells successfully to stimulate T cells in vitro, and investigated the cell differentiation and anti-tumor efficiency. We observed that EphA2-CAR T cells stimulated by B cells performed enhanced anti-tumor ability with more interferon γ (IFN γ) production and higher OX40 expression. The differentiation of CAR T cells was arrested after B cells stimulation for more than 7 days with the percentage of central memory T cells (Tcm) increasing. In addition, next generation sequencing was performed. The top expressed genes clustered in activation, leukocyte migration and chemokine signaling pathway contributed to the anti-glioblastoma (GBM) activity of CAR T cells stimulated by B cell. In conclusion, these results indicated the importance of B cells in retarding CAR T cells differentiation and enhancing anti-tumor activity, which paves the way for the rapid exploitation of EphA2-CAR T cells against GBM in the future.