Project description:The gut microbiome modulates immunotherapy treatment responses, and this may explain why immune checkpoint inhibitors (ICI), such as anti-PD-1, are only effective in some patients. Previous studies correlated lipopolysaccharide (LPS)-producing gut microbes with poorer prognosis; however, LPS from diverse bacterial species can range from immunostimulatory to inhibitory. By functionally analyzing fecal metagenomes from 112 melanoma patients, we found that a subset of LPS-producing bacteria encoding immunostimulatory hexa-acylated LPS was enriched in microbiomes of clinical responders. In an implanted tumor mouse model of anti-PD-1 treatment, microbiota-derived hexa-acylated LPS was required for effective anti-tumor immune responses, and LPS-binding antibiotics and a small molecule TLR4 antagonist abolished anti-PD-1 efficacy. Conversely, oral administration of hexa-acylated LPS to mice significantly augmented anti-PD-1-mediated anti-tumor immunity. Penta-acylated LPS did not improve anti-PD-1 efficacy in vivo and inhibited hexa-acylated LPS-induced immune activation in vitro. Microbiome hexa-acylated LPS therefore represents an accessible predictor and potential enhancer of immunotherapy responses.
Project description:Immune checkpoint blockade is able to achieve durable responses in a subset of patients, however we lack a satisfying comprehension of the underlying mechanisms of anti-CTLA-4 and anti-PD-1 induced tumor rejection. To address these issues we utilized mass cytometry to comprehensively profile the effects of checkpoint blockade on tumor immune infiltrates in human melanoma and murine tumor models. These analyses reveal a spectrum of tumor infiltrating T cell populations that are highly similar between tumor models and indicate that checkpoint blockade targets only specific subsets of tumor infiltrating T cell populations. Anti-PD-1 predominantly induces the expansion of specific tumor infiltrating exhausted-like CD8 T cell subsets. In contrast, anti-CTLA-4 induces the expansion of an ICOS+ Th1-like CD4 effector population in addition to engaging specific subsets of exhausted-like CD8 T cells. Thus, our findings indicate that anti-CTLA-4 and anti-PD-1 checkpoint blockade induced immune responses are driven by distinct cellular mechanisms.
Project description:<p>Antibody blockade of the inhibitory CTLA-4 pathway has led to clinical benefit in a subset of patients with metastatic melanoma. Anti-CTLA-4 enhances T cell responses, including production of IFN-γ, which is a critical cytokine for host immune responses. However, the role of IFN-γ signaling in tumor cells in the setting of anti-CTLA-4 therapy remains unknown. Here we demonstrate that, based upon exome sequencing data, patients identified as non-responders to anti-CTLA-4 (ipilimumab) harbor a much higher genomic defects in the IFN-γ pathway genes than melanoma patients who had clinical response to ipilimumab therapy.</p>
Project description:The paper describes a model of antitumor vaccine therapy.
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This model is described in the article:
A Mathematical Model of the Enhancement of Tumor Vaccine Efficacy by Immunotherapy
Shelby Wilson and Doron Levy
Bull Math Biol. 2012 July ; 74(7)
Abstract:
TGF-β is an immunoregulatory protein that contributes to inadequate antitumor immune responses in cancer patients. Recent experimental data suggests that TGF-β inhibition alone, provides few clinical benefits, yet it can significantly amplify the anti-tumor immune response when combined with a tumor vaccine. We develop a mathematical model in order to gain insight into the cooperative interaction between anti-TGF-β and vaccine treatments. The mathematical model follows the dynamics of the tumor size, TGF-β concentration, activated cytotoxic effector cells, and regulatory T cells. Using numerical simulations and stability analysis, we study the following scenarios: a control case of no treatment, anti-TGF-β treatment, vaccine treatment, and combined anti-TGF-β vaccine treatments. We show that our model is capable of capturing the observed experimental results, and hence can be potentially used in designing future experiments involving this approach to immunotherapy.
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Project description:Tumor necrosis factor-related weak inducer of apoptosis, TWEAK, is a TNF superfamily member that mediates signaling through its receptor fibroblast growth factor inducible-14, Fn14. In tumor cell lines, TWEAK induces proliferation, survival and NF-kappaB signaling and gene expression that promote tumor growth and suppress antitumor immune responses. Anti-TWEAK antibody, RG7212, inhibits tumor growth in vivo with decreases in pathway activation markers and modulation of tumor, blood and spleen immune cell composition. Candidate response prediction markers, including Fn14, have been identified in mouse models. Phase I pharmacodynamic data from patients are consistent with preclinical results. TWEAK:Fn14 signaling is upregulated in human cancer and pathway activation induces tumor proliferation and survival signaling. Blockade with anti-TWEAK mAb, RG7212, inhibits tumor growth in multiple models in mice. TWEAK induces changes that suppress anti-tumor immune responses and RG7212 blocks these effects resulting in changes in tumor immune cell composition and decreases in cytokines that promote immunosuppression. Antitumor efficacy in mice was observed in a range of Fn14 expressing models with pathway activation and expressing either wild-type or mutant p53, BRAF or KRAS suggesting both a patient selection strategy and potential broad clinical applicability. Preclinical mechanism of action hypotheses are supported by Phase I clinical data, with decreases in proliferation markers and increased tumor T cell infiltration. CAKI cells impanted as xenografts in Athymic, Nu/Nu nude mice, treated with anti-TWEAK antibody (TW212) or Vehicle for 24 hours. Four replicates for each condition were performed. RNA was extracted from xenografts, processed and hybridized to human and mouse chips.
Project description:Tumor necrosis factor-related weak inducer of apoptosis, TWEAK, is a TNF superfamily member that mediates signaling through its receptor fibroblast growth factor inducible-14, Fn14. In tumor cell lines, TWEAK induces proliferation, survival and NF-kappaB signaling and gene expression that promote tumor growth and suppress antitumor immune responses. Anti-TWEAK antibody, RG7212, inhibits tumor growth in vivo with decreases in pathway activation markers and modulation of tumor, blood and spleen immune cell composition. Candidate response prediction markers, including Fn14, have been identified in mouse models. Phase I pharmacodynamic data from patients are consistent with preclinical results. TWEAK:Fn14 signaling is upregulated in human cancer and pathway activation induces tumor proliferation and survival signaling. Blockade with anti-TWEAK mAb, RG7212, inhibits tumor growth in multiple models in mice. TWEAK induces changes that suppress anti-tumor immune responses and RG7212 blocks these effects resulting in changes in tumor immune cell composition and decreases in cytokines that promote immunosuppression. Antitumor efficacy in mice was observed in a range of Fn14 expressing models with pathway activation and expressing either wild-type or mutant p53, BRAF or KRAS suggesting both a patient selection strategy and potential broad clinical applicability. Preclinical mechanism of action hypotheses are supported by Phase I clinical data, with decreases in proliferation markers and increased tumor T cell infiltration. ACHN cells impanted as xenografts in Athymic, Nu/Nu nude mice, treated with anti-TWEAK antibody (TW212), B20 antibody control or Vehicle for 4 hours, 8 hours, or 24 hours. Five replicates for each condition were performed.
Project description:Mathematical modeling of immune modulation by glucocorticoids
Konstantin Yakimchuk
https://doi.org/10.1016/j.biosystems.2019.104066
Abstract
The cellular and molecular mechanisms of immunomodulatory actions of glucocorticoids (GC) remain to be identified. Using our experimental findings, a mathematical model based on a system of ordinary differential equations for characterization of the regulation of anti-tumor immune activity by the both direct and indirect GC effects was generated to study the effects of GC treatment on effector CD8+ T cells, GC-generated tolerogenic dendritic cells (DC), regulatory T cells and the growth of lymphoma cells. In addition, we compared the data from in vivo and in silico experiments. The mathematical simulations indicated that treatment with GCs may suppress anti-tumor immune response in a dose-dependent manner. The model simulations were in line with earlier experimental observations of inhibitory effects of GCs on T and NK cells and DCs. The results of this study might be useful for predicting clinical outcomes in patients receiving GC therapy.
Project description:Although genomic instability can trigger cancer-intrinsic innate immune responses that promote tumor rejection, cancer cells often evade these responses by overexpressing immune checkpoint regulators, such as PD-L1. Here, we identify the SNF2-family DNA translocase SMARCAL1 as a factor that favors tumor immune evasion by a dual mechanism involving both the suppression of innate immune signaling and the induction of PD-L1-mediated immune checkpoint responses. Mechanistically, SMARCAL1 relieves endogenous DNA damage and suppresses cGAS-STING-dependent immune signaling during cancer cell growth. Simultaneously, it cooperates with the AP-1 family member JUN to maintain chromatin accessibility at a transcriptional regulatory element in the PD-L1 gene, thereby promoting PD-L1 expression in cancer cells. Loss of SMARCAL1 enhances anti-tumor immune responses and sensitizes tumors to immune checkpoint blockade in a mouse melanoma model. Collectively, these studies uncover SMARCAL1 as a valuable target for cancer immunotherapy.
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-?) induced alterations to antigen presentation, using a lymphoma cell line. IFN-? 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-? exposure. This finding suggests that a modest proteomic response to IFN-? could create larger alteration to cells antigen repertoires. Accordingly, by surveying immunopeptides, distinct peptide repertoires were exclusively observed in the IFN-? induced samples. Furthermore, an additional set of presented peptides distinguished control and the IFN-? 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-? 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.