Epigenetic therapy activates type I interferon signaling in murine ovarian cancer to reduce immunosuppression and tumor burden

Ovarian cancer is the most lethal of all gynecological cancers, and there is an urgent unmet need to develop new therapies. Epithelial ovarian cancer (EOC) is characterized by an immune suppressive microenvironment, and response of ovarian cancers to immune therapies has thus far been disappointing. We now find, in a mouse model of EOC, that clinically relevant doses of DNA methyltransferase and histone deacetylase inhibitors (DNMTi and HDACi, respectively) reduce the immune suppressive microenvironment through type I IFN signaling and improve response to immune checkpoint therapy. These data indicate that the type I IFN response is required for effective in vivo antitumorigenic actions of the DNMTi 5-azacytidine (AZA). Through type I IFN signaling, AZA increases the numbers of CD45+ immune cells and the percentage of active CD8+ T and natural killer (NK) cells in the tumor microenvironment, while reducing tumor burden and extending survival. AZA also increases viral defense gene expression in both tumor and immune cells, and reduces the percentage of macrophages and myeloid-derived suppressor cells in the tumor microenvironment. The addition of an HDACi to AZA enhances the modulation of the immune microenvironment, specifically increasing T and NK cell activation and reducing macrophages over AZA treatment alone, while further increasing the survival of the mice. Finally, a triple combination of DNMTi/HDACi plus the immune checkpoint inhibitor α-PD-1 provides the best antitumor effect and longest overall survival, and may be an attractive candidate for future clinical trials in ovarian cancer.

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765 The first-in-class small molecule TREX1 inhibitor CPI-381 demonstrates type I IFN induction and sensitization of tumors to immune checkpoint blockade

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.765 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A800-A800

Author(s):

Costa Salojin ◽

Anna Gardberg ◽

Valerie Vivat ◽

Lei Cui ◽

Jeffrey Lauer ◽

...

Keyword(s):

Innate Immunity ◽

Tumor Growth ◽

Small Molecule ◽

Immune Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Blockade ◽

Checkpoint Blockade ◽

Type I ◽

Type I Ifn ◽

Syngeneic Tumor

BackgroundTREX1 is an exonuclease that functions as a negative regulator of innate immunity. TREX1 controls dsDNA sensing in tumor and immune cells by preventing aberrant dsDNA buildup that triggers STING-mediated Type 1 Interferon (IFN) induction leading to priming of the adaptive immune system. Loss of function mutations in TREX1 and genetic ablation of trex1 in mice lead to induction of IFNbeta-driven autoimmunity. Thus, TREX1 is a promising target to elicit IFN-mediated anti-tumor immunity.MethodsTo characterize TREX1 inhibitors we developed cell-based assays utilizing human HCT116 carcinoma and THP-1 monocytic Dual reporter cell lines to monitor IRF activity. Activation of cGAS was assessed by measuring cGAMP levels in B16F10 melanoma cells. The potency of TREX1 inhibitors in primary human dendritic cells (DC)s was analyzed by measuring IFNbeta induction by exogenous dsDNA. Analysis of tumor growth inhibition following TREX1 inhibitor treatment was conducted in mouse syngeneic tumor models. TREX1 activity was assessed by measuring degradation of a custom dsDNA substrate.ResultsWe report here the development of a small molecule TREX1 inhibitor, CPI-381, with nanomolar cellular potency, which translated into a robust induction of IRF reporter activity. We observed a significant increase in cGAMP production in B16F10 cells transfected with DNA in the presence of CPI-381, suggesting that CPI-381-mediated inhibition of TREX1 leads to the activation of dsDNA sensors, such as cGAS. Treatment of THP-1 cells with CPI-381 induced the expression of several key ISG involved in innate immunity. Moreover, inhibition of TREX1 with CPI-381 phenocopied the effect of TREX1 genetic deletion in primary human DCs by upregulating IFNbeta. To evaluate whether TREX1 negatively regulates IFNbeta production in syngeneic tumor models, we knocked down trex1 in B16F10, MB49, MC38, and CT26 murine cells. Accumulation of cytosolic dsDNA resulted in a substantial increase in IFNbeta secretion by all four TREX1-KO cell lines.In vivo efficacy studies with CPI-381 demonstrated reduced tumor growth in the MC38 syngeneic tumor model either alone or in combination with anti-PD1. We observed a reduction of TREX1 activity in CPI-381 treated tumors, confirming an inverse relationship between TREX1 intra-tumor activity and tumor growth, and efficient target engagement after systemic (oral) delivery.ConclusionsWe have developed a first-in-class, potent TREX1 inhibitor demonstrating excellent in vitro and in vivo potency via enhancement of cytosolic dsDNA sensing and induction of IFNbeta in cancer and immune cells. CPI-381-induced tumor-intrinsic TREX1 inhibition elicits antitumor immunity as a single agent and increases response to immune checkpoint blockade via mechanisms downstream of TREX1 that activate type I IFN signaling.Ethics ApprovalAll animal work was approved and conducted under the oversight of the Charles River Accelerator and Development Lab (CRADL, Cambridge, MA) Institutional Animal Care and Use Committee (protocol # 2021-1258).

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A TLR4 agonist improves immune checkpoint blockade treatment by increasing the ratio of effector to regulatory cells within the tumor microenvironment

Scientific Reports ◽

10.1038/s41598-021-94837-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. Farias ◽

A. Soto ◽

F. Puttur ◽

C. J. Goldin ◽

S. Sosa ◽

...

Keyword(s):

Tumor Microenvironment ◽

Tumor Growth ◽

Therapeutic Effect ◽

Immune Cells ◽

Immune Checkpoint ◽

Combined Treatment ◽

Immune Checkpoint Blockade ◽

Checkpoint Blockade ◽

Regulatory Cells ◽

Ifn Γ

AbstractBrucella lumazine synthase (BLS) is a homodecameric protein that activates dendritic cells via toll like receptor 4, inducing the secretion of pro-inflammatory cytokines and chemokines. We have previously shown that BLS has a therapeutic effect in B16 melanoma-bearing mice only when administered at early stages of tumor growth. In this work, we study the mechanisms underlying the therapeutic effect of BLS, by analyzing the tumor microenvironment. Administration of BLS at early stages of tumor growth induces high levels of serum IFN-γ, as well as an increment of hematopoietic immune cells within the tumor. Moreover, BLS-treatment increases the ratio of effector to regulatory cells. However, all treated mice eventually succumb to the tumors. Therefore, we combined BLS administration with anti-PD-1 treatment. Combined treatment increases the outcome of both monotherapies. In conclusion, we show that the absence of the therapeutic effect at late stages of tumor growth correlates with low levels of serum IFN-γ and lower infiltration of immune cells in the tumor, both of which are essential to delay tumor growth. Furthermore, the combined treatment of BLS and PD-1 blockade shows that BLS could be exploited as an essential immunomodulator in combination therapy with an immune checkpoint blockade to treat skin cancer.

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Randomised phase II trial of olaparib, chemotherapy or olaparib and cediranib in patients with platinum-resistant ovarian cancer (OCTOVA): a study protocol

BMJ Open ◽

10.1136/bmjopen-2020-041463 ◽

2021 ◽

Vol 11 (1) ◽

pp. e041463

Author(s):

Anita Mansouri ◽

Naomi McGregor ◽

Rachel Dunn ◽

Sam Dobbie ◽

Jane Holmes ◽

...

Keyword(s):

Ovarian Cancer ◽

Clinical Trials ◽

Antiangiogenic Therapy ◽

Single Agent ◽

Unmet Need ◽

Dropout Rate ◽

Weekly Paclitaxel ◽

Type I ◽

Link Type ◽

Platinum Based Chemotherapy

IntroductionPatients relapsing within 12 months of platinum-based chemotherapy usually have a poorer response to subsequent treatments. To date, extensive research into the mechanism of resistance to platinum agents in the treatment of ovarian cancer has not resulted in improved responses or longer survival. Further experimental work and clinical trials with novel agents are therefore justified to address this unmet need.Patients with ovarian, fallopian tube or primary peritoneal cancer that has relapsed within 12 months of platinum-based chemotherapy will be randomised with stratification for BReast CAncer gene (BRCA) status, prior poly (ADP-ribose) polymerase (PARP) exposure and prior antiangiogenic therapy into weekly paclitaxel (chemotherapy), olaparib or the combination of cediranib and olaparib. They will be followed until disease progression or unacceptable toxicity develops. Our trial design permits two investigations. We will compare the efficacy and tolerability of single-agent olaparib with weekly paclitaxel. We will also compare the efficacy and tolerability of olaparib with the combination of olaparib and cediranib. The required sample size of 138 participants (46 per arm) was calculated using a 20% one-sided type I error, 80% power and 15% dropout rate. Recruitment will last 34 months with a follow-up of 18 months.Methods and analysisEthics and disseminationThis study will be conducted under a UK Medicines and Healthcare Products Regulatory Agency Clinical Trials Authorisation. Approval to conduct the study was obtained from the responsible authority before beginning the study. The sponsor will retain ownership of all data arising from the trial. We aim to publish this research in a specialist peer-reviewed scientific journal on study completion. EudraCT number: 2016-000559-28, ethics reference number: 16/LO/2150.Trial registration numberISRCTN: ISRCTN14784018, clinicaltrials.gov: NCT03117933; Pre-results.

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EXTH-77. POLIO VIROTHERAPY OF MURINE BRAIN TUMORS INDUCES MICROGLIA PROLIFERATION AND INFLAMMATION THAT IS POTENTIATED BY IMMUNE CHECKPOINT BLOCKADE

Neuro-Oncology ◽

10.1093/neuonc/noab196.716 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi181-vi181

Author(s):

Yuanfan Yang ◽

Michael Brown ◽

Kevin Stevenson ◽

Giselle lopez ◽

Reb Kornahrens ◽

...

Keyword(s):

T Cell ◽

Immune Checkpoint ◽

Response Rate ◽

Cd8 T Cell ◽

Gene Set Enrichment Analysis ◽

Type I ◽

Acute Type ◽

Type I Ifn ◽

Term Survival

Abstract Immunotherapy with polio:rhinovirus recombinant (PVSRIPO) has shown evidence of efficacy in a phase I clinical trial for recurrent GBM, resulting in durable radiographic responses and 21% long-term survival at 36 months. Ongoing research aims to enhance the clinical response rate by resolving the mechanisms of action and therapy resistance in vivo, thereby devising more effective therapies. Mouse glioma (CT2A) cells were intracranially implanted (day 0) in transgenic mice carrying poliovirus receptor CD155, and treated with intratumor PVSRIPO (5×105 pfu; day 6) to dissect early and late events following therapy. A blinded pathological review of 45 post-treatment tumors was performed. On day 8, a histological response, featured by tumor dissociation and shrinkage, with inflammation and microglia enrichment in the treated hemisphere, was common in PVSRIPO group (6/7) compared to controls (0/4). However, the response rate fell over time (7/12 on day 12; 1/7 on day 15) and the therapy was overcome by aggressive tumor regrowth. RNAseq was performed and Gene Set Enrichment Analysis of the tumor microenvironment revealed an acute type-I interferon (IFN)-related inflammation, correlating with the histological findings of profound proinflammatory engagement of microglia (Iba1+) widespread in the treated hemisphere. Microglia proliferation (Ki67+) was observed in the treated hemisphere, likely resulting from PVSRIPO infection, in CT2A and B16 intracranial models. This suggests an association of adaptive antitumor immunity—elicited by immediate intratumor type-I IFN-dominant inflammation—with tumor regression. Thus, buttressing type-I IFN directed antitumor CD8+T cell immunity, e.g. with blockade of the PD1:PD-L1 immune checkpoint, might contribute to tumor remission. Indeed, combination therapy with αPD-L1 antibody in the CT2A model showed longer median survival and higher long-term remission rate compared to monotherapy alone; CD8 T cell depletion can completely abrogate this efficacy with this therapy combination, confirming the role of anti-tumor immunity in this approach.

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Cyclic dinucleotides modulate induced type I IFN responses in innate immune cells by degradation of STING

The FASEB Journal ◽

10.1096/fj.201601093r ◽

2017 ◽

Vol 31 (7) ◽

pp. 3107-3115 ◽

Cited By ~ 6

Author(s):

Christine Rueckert ◽

Ulfert Rand ◽

Urmi Roy ◽

Bahram Kasmapour ◽

Till Strowig ◽

...

Keyword(s):

Immune Cells ◽

Innate Immune ◽

Type I ◽

Innate Immune Cells ◽

Type I Ifn ◽

Cyclic Dinucleotides

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The Tumor Microenvironment of Epithelial Ovarian Cancer and Its Influence on Response to Immunotherapy

Cancers ◽

10.3390/cancers10080242 ◽

2018 ◽

Vol 10 (8) ◽

pp. 242 ◽

Cited By ~ 37

Author(s):

Galaxia Rodriguez ◽

Kristianne Galpin ◽

Curtis McCloskey ◽

Barbara Vanderhyden

Keyword(s):

Ovarian Cancer ◽

Tumor Microenvironment ◽

Epithelial Ovarian Cancer ◽

B Lymphocytes ◽

Immune Cells ◽

Ovarian Cancer Cell ◽

Cell Types ◽

Therapeutic Approaches ◽

Mutational Burden ◽

Tumor Mutational Burden

Immunotherapy as a treatment for cancer is a growing field of endeavor but reports of success have been limited for epithelial ovarian cancer. Overcoming the challenges to developing more effective therapeutic approaches lies in a better understanding of the factors in cancer cells and the surrounding tumor microenvironment that limit response to immunotherapies. This article provides an overview of some ovarian cancer cell features such as tumor-associated antigens, ovarian cancer-derived exosomes, tumor mutational burden and overexpression of immunoinhibitory molecules. Moreover, we describe relevant cell types found in epithelial ovarian tumors including immune cells (T and B lymphocytes, Tregs, NK cells, TAMs, MDSCs) and other components found in the tumor microenvironment including fibroblasts and the adipocytes in the omentum. We focus on how those components may influence responses to standard treatments or immunotherapies.

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Abstract 4907: Epigenetic treatment of ovarian cancer cells increases immune cell recruitment to the tumor microenvironment: implications for response to immune checkpoint therapy

10.1158/1538-7445.am2016-4907 ◽

2016 ◽

Author(s):

Meredith L. Stone ◽

Katherine B. Chiappinelli ◽

Huili Li ◽

Lauren Murphy ◽

Michael Topper ◽

...

Keyword(s):

Ovarian Cancer ◽

Tumor Microenvironment ◽

Cancer Cells ◽

Immune Checkpoint ◽

Immune Cell ◽

Ovarian Cancer Cells ◽

Cell Recruitment ◽

Immune Cell Recruitment

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Distribution of novel immune-checkpoint targets in ovarian cancer tumor microenvironment: A dynamic landscape.

Gynecologic Oncology ◽

10.1016/j.ygyno.2020.09.045 ◽

2021 ◽

Vol 160 (1) ◽

pp. 279-284

Author(s):

Félix Blanc-Durand ◽

Catherine Genestie ◽

Elisa Yaniz Galende ◽

Sébastien Gouy ◽

Philippe Morice ◽

...

Keyword(s):

Ovarian Cancer ◽

Tumor Microenvironment ◽

Immune Checkpoint ◽

Dynamic Landscape ◽

Cancer Tumor

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Targeting the immunosuppressive tumor microenvironment: Synergistic effect of low-dose IL12 in combination with dual immune checkpoint inhibition in a preclinical model of ovarian cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.5_suppl.7 ◽

2020 ◽

Vol 38 (5_suppl) ◽

pp. 7-7

Author(s):

Paul G. Pavicic ◽

Patricia A. Rayman ◽

Hussein Al-Sudani ◽

C. Marcela Diaz-Montero ◽

Haider Mahdi

Keyword(s):

Ovarian Cancer ◽

T Cells ◽

Tumor Microenvironment ◽

Antitumor Activity ◽

Synergistic Effect ◽

Immune Checkpoint ◽

Low Dose ◽

Checkpoint Inhibition ◽

Immune Checkpoint Inhibition ◽

Activated T Cells

7 Background: Epithelial ovarian cancer (OC) is the most lethal gynecologic cancer with ~22,000 women diagnosed annually in the US. The impact of immune checkpoint inhibition (ICI) in the treatment of solid tumors has been significant. However, the response rates for OC are low ranging from 11-15%. It is critical to explore strategies to enhance the efficacy of ICI immunotherapy in OC. Targeting immunosuppressive factors and cells within the tumor microenvironment (TME) represents a feasible approach. The use of IL12 is attractive because induces potent antitumor activity by targeting myeloid cells and lymphocytes. However its clinical application has been hindered by its potential systemic toxicity. Here we explore the use of low dose intraperitoneal IL12 to enhance the antitumor activity of dual ICI in OC. Methods: Mice bearing ID8-VEGF tumors implanted intraperitoneally received either anti-PD1 alone or dual ICI treatment of anti-PD1 plus anti-CTLA4 with or without low dose IL12. Ascites accumulation was used as surrogate for tumor progression and determined by assessing weight increase. Blood and ascites were analyzed by flow cytometry for frequency of PMN-MDSC, M-MDSC, and activated T cells. Results: Low dose IL12 alone induced a significant delay in ascites accumulation when compared to untreated controls or mice treated with PD1 monotherapy or dual ICI. Addition of IL12 to dual ICI resulted in significant tumor regression and extended survival benefit compared to dual ICI alone. A synergistic effect of IL12 was not observed when combined with PD1 monotherapy. Antitumor responses associated with a marked decrease in the frequency of M-MDSC in blood and a decrease in both PMN- and M-MDSC in ascites. Decrease in MDSC associated with elevated levels of activated T cells. Conclusions: Low dose IL12 can induce regression of ID8-VEGF tumors. However, durable responses were only observed when IL12 was added to dual ICI. This suggests that IL12 can induce changes in the TME, particularly on MDSC, that can potentiate the antitumor activity of dual ICI. Our findings also suggest a crucial role of CTLA4 blockade perhaps via Treg targeting.

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