TREX1 Inactivation Unleashes Cancer Cell STING-Interferon Signaling and Promotes Antitumor Immunity

STING in cancer immunoediting: Modeling tumor-immune dynamics throughout cancer development

Cancer immunoediting is a dynamic process of tumor-immune system interaction that plays a critical role in cancer development and progression. Recent studies have highlighted the importance of innate signaling pathways possessed by both cancer cells and immune cells in this process. The STING molecule, a pivotal innate immune signaling molecule, mediates DNA-triggered immune responses in both cancer cells and immune cells, modulating the anti-tumor immune response and shaping the efficacy of immunotherapy. Emerging evidence has shown that the activation of STING signaling has dual opposing effects in cancer progression, simultaneously provoking and restricting anti-tumor immunity, and participating in every phase of cancer immunoediting, including immune elimination, equilibrium, and escape. In this review, we elucidate the roles of STING in the process of cancer immunoediting and discuss the dichotomous effects of STING agonists in the cancer immunotherapy response or resistance. A profound understanding of the sophisticated roles of STING signaling pathway in cancer immunoediting would potentially inspire the development of novel cancer therapeutic approaches and overcome the undesirable protumor effects of STING activation.

Regulation of cGAS-STING signalling and its diversity of cellular outcomes

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signalling pathway, which recognizes both pathogen DNA and host-derived DNA, has emerged as a crucial component of the innate immune system, having important roles in antimicrobial defence, inflammatory disease, ageing, autoimmunity and cancer. Recent work suggests that the regulation of cGAS-STING signalling is complex and sophisticated. In this Review, we describe recent insights from structural studies that have helped to elucidate the molecular mechanisms of the cGAS-STING signalling cascade and we discuss how the cGAS-STING pathway is regulated by both activating and inhibitory factors. Furthermore, we summarize the newly emerging understanding of crosstalk between cGAS-STING signalling and other signalling pathways and provide examples to highlight the wide variety of cellular processes in which cGAS-STING signalling is involved, including autophagy, metabolism, ageing, inflammation and tumorigenesis.

Chromosomal instability as a driver of cancer progression

Chromosomal instability (CIN) refers to an increased propensity of cells to acquire structural and numerical chromosomal abnormalities during cell division, which contributes to tumour genetic heterogeneity. CIN has long been recognized as a hallmark of cancer, and evidence over the past decade has strongly linked CIN to tumour evolution, metastasis, immune evasion and treatment resistance. Until recently, the mechanisms by which CIN propels cancer progression have remained elusive. Beyond the generation of genomic copy number heterogeneity, recent work has unveiled additional tumour-promoting consequences of abnormal chromosome segregation. These mechanisms include complex chromosomal rearrangements, epigenetic reprogramming and the induction of cancer cell-intrinsic inflammation, emphasizing the multifaceted role of CIN in cancer.

siRNA-based therapy for overcoming drug resistance in human solid tumours; molecular and immunological approaches

RNA interference (RNAi) is a primordial biological process that protects against external intrusion. SiRNA has the potential to selectively silence disease-related genes in a sequence-specific way, thus offering a promising therapeutic approach. The efficacy of siRNA-based therapies in cancer treatment has gained significant recognition due to multiple studies demonstrating its ability to effectively suppress cancer cells' growth and multiplication. Moreover, siRNA-based medicines have shown considerable promise in enhancing the sensitivity of cancer cells to chemotherapy and other treatment methods by suppressing genes that play a role in the development of drug resistance. Exploring and identifying functional genes linked to cancer cell characteristics and drug resistance is crucial for developing effective siRNAs for cancer treatment and advancing targeted and personalized therapeutics. Targeting and silencing genes in charge of resistance mechanisms, such as those involved in drug efflux, cell survival, or DNA repair, is possible with siRNA therapy in the context of drug resistance, especially cancer. Through inhibiting these genes, siRNA therapy can prevent resistance and restore the efficacy of traditional medications. This review addresses the potential of siRNAs in addressing drug resistance in human tumours, opening up new possibilities in cancer therapy. This review article offers a non-systematic summary of how different siRNA types contribute to cancer cells' treatment resistance. Using pertinent keywords, sources were chosen from reliable databases, including PubMed, Scopus, and Google Scholar. The review covered essential papers in this area and those that mainly addressed the function of siRNA in drug resistance. The articles examined in connection with the title of this review were primarily published from 2020 onward and are based on in vitro studies. Furthermore, this article examines the potential barriers and prospective perspectives of siRNA therapies.

Homogeneous and bioluminescent biochemical and cellular assay for monitoring cGAMP and enzymes that generate and degrade cGAMP

The cyclic GMP-AMP synthase-stimulator of the interferon gene (cGAS-STING) signaling pathway is considered an essential pattern recognition and effector pathway in the natural immune system and is mainly responsible for recognizing DNA molecules present in the cytoplasm and activating downstream signaling pathways to generate type I interferons (IFN-I) and other inflammatory factors. STING, a crucial junction protein in the innate immune system, exerts an essential role in host resistance to external pathogen invasion. The DNA introduced by pathogens or tumors is recognized by the cytoplasmic nucleic acid receptor cGAS, and a second messenger, cGAMP, is generated using intracellular guanosine triphosphate (GTP) and adenosine triphosphate (ATP). Furthermore, cellular and extracellular cGAMP concentrations are also controlled by ENPP1, an enzyme that breaks down cGAMP to AMP and GMP. Therefore, the role of the cGAS-STING signaling pathway has generated great interest in inflammatory and cancer research. To advance our understanding of innate immune system and in particular the STING pathway, we have developed a homogeneous, bioluminescent cGAMP detection assay that is very sensitive and highly selective against other nucleotides, cyclic nucleotides, and dicyclic nucleotides. The assay can be also used to monitor the activity of cGAS and ENPP1 to enable the development of inhibitors of both enzymes which might be used for therapeutic applications.

The Simultaneous Treatment of PC-3 Cells with the DNA-Demethylating Agent Decitabine and S-Adenosylmethionine Leads to Synergistic Anticancer Effects

Background: Epigenetic dysregulation is a common feature of cancer. Promoter demethylation of tumor-promoting genes and global DNA hypomethylation may trigger tumor progression. Epigenetic changes are unstable; thus, research has focused on detecting remedies that target epigenetic regulators. Previous studies have suggested that concordantly targeting hypomethylation and hypermethylation is beneficial for suppressing both the oncogenic and pro-metastatic functions of cancer cells. Therefore, we aimed to investigate the effect of a combination of S-adenosylmethionine (SAM) and the demethylating agent decitabine on prostate cancer cells. Materials and Methods: Prostate cancer cells (PC-3) were treated with SAM, decitabine, or a combination of both. Proliferation, migration, invasion, and methylation assays were also performed. A transcriptome study was conducted to detect different gene clusters between the treatment groups, followed by analyses using the Kyoto Encyclopedia of Genes and Genomes pathway and ingenuity pathway analysis. Finally, to gain information on differential gene expression, promoter methylation studies were performed. Results: Groups treated with decitabine, SAM, or their combination showed reduced proliferative capacity. The decitabine-treated group showed a marginal increase in cell migration and invasion, whereas the SAM-treated and combination treatment groups showed reduced invasion and migration potential. Methylation assays demonstrated the restoration of decitabine-induced demethylation in prostate cancer samples, whereas the transcriptome study revealed the upregulation of different gene clusters between the treatment groups. Methylation studies confirmed that SAM could restore the decitabine-induced demethylation of proto-oncogenes, but it did not induce the re-methylation of tumor-suppressor genes. Conclusions: Combination treatment with SAM and decitabine had an additive effect and did not nullify each other.

Tissue factor promotes TREX1 protein stability to evade cGAS-STING innate immune response in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains the most challenging human malignancy that urgently needs effective therapy. Tissue factor (TF) is expressed in ~80% of PDAC and represents a potential therapeutic target. While a novel TF-ADC (MRG004A) demonstrated efficacy for PDAC and TNBC in a Phase I/II trial [Ref. 18], the functional role of TF in PDAC remains incompletely understood. We investigated the relationship between TF and the innate STING pathway. We found that patients with TF-overexpression had poor survival, very low levels of P-STING/P-TBK1, reduced amounts of ISGs and chemokines as well as low numbers of cytotoxic immunocytes in their tumor. In experimental models of mouse and human PDAC, tumor cell-intrinsic TF expression played a major role in silencing the cytosolic micronuclei sensing and cGAS-STING activation. This process involved a TREX1 exonuclease-dependent clearance of micronucleus-DNA accumulated in tumor cells. Treatment of tumors with TF-KO/shRNA or anti-TF antibody HuSC1-39 (parent antibody of MRG004A) triggered a rapid and proteasome-dependent degradation of TREX1 thereby restoring the STING/TBK1 cascade phosphorylation. TF-inhibition therapy promoted a robust STING/IRF3-dependent IFN/CCL5/CXCL9-11 production, immune effector cell infiltration and antitumor efficacy. Moreover, in the PBMC and cancer cell co-culture, TF-inhibition synergized with a STING agonist compound. A covalently conjugated TF antibody-STING agonist ADC strongly increased the efficacy of tumor-targeted STING agonism on chemokine secretion and tumor inhibition in vitro and in vivo. Thus, TF-inhibition reshapes an "immune hot" tumor environment. TF-targeted therapy warrants clinical investigation as a single agent or in combination with immunotherapy for treating TF-positive PDAC and TNBC.

RNA sensing induced by chromosome missegregation augments anti-tumor immunity

Viral mimicry driven by endogenous double-stranded RNA (dsRNA) stimulates innate and adaptive immune responses. However, the mechanisms that regulate dsRNA-forming transcripts during cancer therapy remain unclear. Here, we demonstrate that dsRNA is significantly accumulated in cancer cells following pharmacologic induction of micronuclei, stimulating mitochondrial antiviral signaling (MAVS)-mediated dsRNA sensing in conjunction with the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway. Activation of cytosolic dsRNA sensing cooperates with double-stranded DNA (dsDNA) sensing to upregulate immune cell migration and antigen-presenting machinery. Tracing of dsRNA-sequences reveals that dsRNA-forming transcripts are predominantly generated from non-exonic regions, particularly in locations proximal to genes exhibiting high chromatin accessibility. Activation of this pathway by pulsed monopolar spindle 1 (MPS1) inhibitor treatment, which potently induces micronuclei formation, upregulates cytoplasmic dsRNA sensing and thus promotes anti-tumor immunity mediated by cytotoxic lymphocyte activation in vivo. Collectively, our findings uncover a mechanism in which dsRNA sensing cooperates with dsDNA sensing to boost immune responses, offering an approach to enhance the efficacy of cancer therapies targeting genomic instability.

cGAS-STING signaling pathway in lung cancer: Regulation on antitumor immunity and application in immunotherapy

The innate immune system has a primary role in defending against external threats, encompassing viruses, bacteria, and fungi, thereby playing a pivotal role in establishing robust protection. Recent investigations have shed light on its importance in the progression of tumors, with a particular emphasis on lung cancer. Among the various signaling pathways implicated in this intricate process, the cGAS-STING pathway emerges as a significant participant. Cyclic GMP-AMP synthase (cGAS) discerns free DNA and activates the stimulator of interferon genes (STING), subsequently culminating in the secretion of cytokines and exerting inhibitory effects on tumor development. Consequently, researchers are increasingly interested in creating anticancer drugs that specifically target the cGAS-STING pathway, offering promising avenues for novel therapeutic interventions. The objective of this review is to present a comprehensive overview of the ongoing research on the cGAS-STING signaling pathway within the realm of lung cancer. The primary emphasis is on understanding its involvement in lung cancer development and assessing its viability as a target for innovative therapeutic options.

Oncogenic RAS in Cancers from the DNA Replication Stress and Senescence Perspective

Rat Sarcoma (RAS)-driven cancers have been one of the main foci in the field of cancer science for over four decades. Despite significant improvement in understanding the biology of RAS oncogene, the method to target RAS-mutated cancers is still unclear. In recent years, the role for RAS beyond its hyperproliferation has been extensively documented. In this review, we systematically address and dwell on the details of the mechanisms of RAS oncogene-mediated alteration in the DNA replication and DNA damage response (DDR) pathways, focusing on lung cancers. We further extend this molecular connection towards cytosolic DNA accumulation, innate immune activation and senescence in RAS-addicted cancers. At the end, we briefly speculate on the potential strategies for targeting RAS mutated lung cancers, considering various approaches targeting DNA replication, DNA repair and the cGAS-STING pro-inflammatory pathway. These new lines of therapy, especially when used in combinations, may enhance treatment efficacy and overcome the challenges associated with these mutations.

Chromothripsis in cancer

Chromothripsis is a mutational phenomenon in which a single catastrophic event generates extensive rearrangements of one or a few chromosomes. This extreme form of genome instability has been detected in 30-50% of cancers. Studies conducted in the past few years have uncovered insights into how chromothripsis arises and deciphered some of the cellular and molecular consequences of chromosome shattering. This Review discusses the defining features of chromothripsis and describes its prevalence across different cancer types as indicated by the manifestations of chromothripsis detected in human cancer samples. The different mechanistic models of chromothripsis, derived from in vitro systems that enable causal inference through experimental manipulation, are discussed in detail. The contribution of chromothripsis to cancer development, the selective advantages that cancer cells might gain from chromothripsis, the evolutionary trajectories of chromothriptic tumours, and the potential vulnerabilities and therapeutic opportunities presented by chromothriptic cells are also highlighted.

The hallmarks of cancer immune evasion

According to the widely accepted "three Es" model, the host immune system eliminates malignant cell precursors and contains microscopic neoplasms in a dynamic equilibrium, preventing cancer outgrowth until neoplastic cells acquire genetic or epigenetic alterations that enable immune escape. This immunoevasive phenotype originates from various mechanisms that can be classified under a novel "three Cs" conceptual framework: (1) camouflage, which hides cancer cells from immune recognition, (2) coercion, which directly or indirectly interferes with immune effector cells, and (3) cytoprotection, which shields malignant cells from immune cytotoxicity. Blocking the ability of neoplastic cells to evade the host immune system is crucial for increasing the efficacy of modern immunotherapy and conventional therapeutic strategies that ultimately activate anticancer immunosurveillance. Here, we review key hallmarks of cancer immune evasion under the "three Cs" framework and discuss promising strategies targeting such immunoevasive mechanisms.

DNASE1L3-mediated PANoptosis enhances the efficacy of combination therapy for advanced hepatocellular carcinoma

Rationale: The introduction of combination therapy utilizing tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors for advanced hepatocellular carcinoma (HCC) has significantly altered the management of affected patients. However, the absence of predictive biomarkers to identify those who would derive the greatest benefit from this combination therapy underscores the necessity for further enhancements in its efficacy. Methods: In this study, we performed a proteomic analysis on surgical specimens from patients who either responded to or did not respond to combination therapy with sorafenib and programmed death-1 (PD-1) monoclonal antibody (mAb). We employed in vitro experiments, including immunocytochemistry, co-immunoprecipitation, and transmission electron microscopy, to elucidate the mechanism of DNASE1L3-induced PANoptosis. Additionally, we assessed the function of DNASE1L3 in combination therapy using a mouse liver orthotopic tumor model and clinical samples. Results: Our findings indicated that the levels of deoxyribonuclease 1 like 3 (DNASE1L3) were significantly elevated in the cohort of patients who responded to treatment, correlating with the sorafenib-induced programmed cell death (PCD) of HCC cells. Further experimentation revealed that DNASE1L3 facilitated the generation of double-strand deoxyribonucleic acid (dsDNA) breaks and activated the absent in melanoma 2 (AIM2) pathway during sorafenib-induced HCC cell death, ultimately culminating in PANoptosis. Moreover, DNASE1L3-induced PANoptosis augmented the activation of anti-tumor immunity within the tumor microenvironment (TME), thereby enhancing the efficacy of the combination therapy involving sorafenib and PD-1 mAb. Conclusion: Our findings offer valuable insights into the mechanisms underlying DNASE1L3's role in sorafenib sensitivity and position DNASE1L3 as a promising predictive biomarker and target for improving outcomes in combination therapy for HCC.

The role of cGAS-STING signaling in rheumatoid arthritis: from pathogenesis to therapeutic targets

Rheumatoid arthritis (RA) is a systemic autoimmune disease primarily characterized by erosive and symmetric polyarthritis. As a pivotal axis in the regulation of type I interferon (IFN-I) and innate immunity, the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway has been implicated in the pathogenesis of RA. This pathway mainly functions by regulating cell survival, pyroptosis, migration, and invasion. Therefore, understanding the sources of cell-free DNA and the mechanisms underlying the activation and regulation of cGAS-STING signaling in RA offers a promising avenue for targeted therapies. Early detection and interventions targeting the cGAS-STING signaling are important for reducing the medical burden on individuals and healthcare systems. Herein, we review the existing literature pertaining to the role of cGAS-STING signaling in RA, and discuss current applications and future directions for targeting the cGAS-STING signaling in RA treatments.

Generating Cytokines and Growth Factors for Functional Activity: Feasibility of Method Using MIF Protein

Cytokines and growth factors are signaling molecules that regulate a variety of biological processes. Understanding their role is essential for basic research and clinical utilization. Thus, cytokines and growth factors are widely used throughout research labs in a significant number of applications. Additionally, genetic polymorphisms result in variant forms of cytokines and growth factors, which can alter their function. Becoming more common, researchers will need to generate these important proteins and their variants themselves in functional forms for activity studies. The expression systems used to generate these proteins can have a major impact on their function. In some instances, post-translational modifications are needed to produce a functionally active protein, which can only be conducted using eukaryotic expression systems. Ideally, for functional relevance, a human expression system should be used for human-related research and applications. Most human cell-based expression systems primarily use HEK (Human Embryonic Kidney) cells; however, relying on just one cell type can lead to several issues, considering the variety of proteins derived from various cell sources. Here, we provide a protocol to effectively and efficiently generate functional recombinant proteins, taking into consideration the diverse range of proteins from different cell types throughout the human body.

Targeting TREX1 Induces Innate Immune Response in Drug-Resistant Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is the most lethal type of lung cancer. Paradoxically, this tumor displays an initial exquisite response to chemotherapy; however, at relapse, the tumor is highly resistant to subsequent available therapies. Here, we report that the expression of three prime repair exonuclease 1 (TREX1) is strongly induced in chemoresistant SCLCs. Assay for transposase-accessible chromatin using sequencing and chromatin immunoprecipitation sequencing revealed a significant increase in chromatin accessibility and transcriptional activity of TREX1 gene locus in chemoresistant SCLCs. Analyses of human SCLC tumors and patient-derived xenografts (PDX) also showed an increase in TREX1 expression in postchemotherapy samples. TREX1 depletion caused the activation of cyclic GMP-AMP synthase stimulator of interferon gene pathway due to cytoplasmic accumulation of damage-associated double-stranded DNA, inducing immunogenicity and enhancing the sensitivity of drug-resistant cells to chemotherapy. These findings suggest TREX1 upregulation may partially contribute to the survival of resistant cells, and its inhibition may represent a promising therapeutic strategy to enhance antitumor immunity and potentiate the efficacy of chemotherapy and/or immunotherapy in chemoresistant SCLCs. Significance: In this study, we show that targeting TREX1 induces an innate immune response and resensitizes SCLC cells to chemotherapy, representing a promising novel target for "immunologically" cold tumors, such as SCLC.

Manganese boosts natural killer cell function via cGAS-STING mediated UTX expression

Natural killer (NK) cells play a crucial role in both innate immunity and the activation of adaptive immunity. The activating effect of Mn2+ on cyclic GMP-AMP(cGAS)-stimulator of interferon genes (STING signaling has been well known, but its effect on NK cells remains elusive. In this study, we identified the vital role of manganese (Mn2+) in NK cell activation. Mn2+ directly boosts cytotoxicity of NK cells and promotes the cytokine secretion by NK cells, thereby activating CD8+ T cells and enhancing their antitumor activity. Furthermore, Mn2+ can simultaneously activate NK-cell intrinsic cGAS and STING and consequently augment the expression of ubiquitously transcribed tetratricopeptide repeat on chromosome X (UTX to promote the responsiveness of NK cells. Our results contribute to a broader comprehension of how cGAS-STING regulates NK cells. As a potent agonist of cGAS-STING, Mn2+ provides a promising option for NK cell-based immunotherapy of cancers.

Targeting chromosomal instability in patients with cancer

Chromosomal instability (CIN) is a hallmark of cancer and a driver of metastatic dissemination, therapeutic resistance, and immune evasion. CIN is present in 60-80% of human cancers and poses a formidable therapeutic challenge as evidenced by the lack of clinically approved drugs that directly target CIN. This limitation in part reflects a lack of well-defined druggable targets as well as a dearth of tractable biomarkers enabling direct assessment and quantification of CIN in patients with cancer. Over the past decade, however, our understanding of the cellular mechanisms and consequences of CIN has greatly expanded, revealing novel therapeutic strategies for the treatment of chromosomally unstable tumours as well as new methods of assessing the dynamic nature of chromosome segregation errors that define CIN. In this Review, we describe advances that have shaped our understanding of CIN from a translational perspective, highlighting both challenges and opportunities in the development of therapeutic interventions for patients with chromosomally unstable cancers.

TBK1 is paradoxical in tumor development: a focus on the pathway mediating IFN-I expression

TANK-binding kinase 1 (TBK1) is a member of the IKK family and plays a crucial role in the activation of non-canonical NF-κB signaling and type I interferon responses. The aberrant activation of TBK1 contributes to the proliferation and survival of various types of tumor cells, particularly in specific mutational or tumorous contexts. Inhibitors targeting TBK1 are under development and application in both in vivo and in vitro settings, yet their clinical efficacy remains limited. Numerous literatures have shown that TBK1 can exhibit both tumor promoting and tumor inhibiting effects. TBK1 acts as a pivotal node within the innate immune pathway, mediating anti-tumor immunity through the activation of innate immune responses. Facilitating interferon-I (IFN-I) production represents a critical mechanism through which TBK1 bridges these processes. IFN has been shown to exert both beneficial and detrimental effects on tumor progression. Hence, the paradoxical role of TBK1 in tumor development may necessitate acknowledgment in light of its downstream IFN-I signaling cascade. In this paper, we review the signaling pathways mediated by TBK1 in various tumor contexts and summarize the dual roles of TBK1 and the TBK1-IFN pathways in both promoting and inhibiting tumor progression. Additionally, we highlight the significance of the TBK1-IFN pathway in clinical therapy, particularly in the context of immune response. We anticipate further advancements in the development of TBK1 inhibitors as part of novel cancer treatment strategies.

From mechanism to therapy: the journey of CD24 in cancer

CD24 is a glycosylphosphatidylinositol-anchored protein that is expressed in a wide range of tissues and cell types. It is involved in a variety of physiological and pathological processes, including cell adhesion, migration, differentiation, and apoptosis. Additionally, CD24 has been studied extensively in the context of cancer, where it has been found to play a role in tumor growth, invasion, and metastasis. In recent years, there has been growing interest in CD24 as a potential therapeutic target for cancer treatment. This review summarizes the current knowledge of CD24, including its structure, function, and its role in cancer. Finally, we provide insights into potential clinical application of CD24 and discuss possible approaches for the development of targeted cancer therapies.

Revitalizing antitumor immunity: Leveraging nucleic acid sensors as therapeutic targets

Nucleic acid sensors play a critical role in recognizing and responding to pathogenic nucleic acids as danger signals. Upon activation, these sensors initiate downstream signaling cascades that lead to the production and release of pro-inflammatory cytokines, chemokines, and type I interferons. These immune mediators orchestrate diverse effector responses, including the activation of immune cells and the modulation of the tumor microenvironment. However, careful consideration must be given to balancing the activation of nucleic acid sensors to avoid unwanted autoimmune or inflammatory responses. In this review, we provide an overview of nucleic acid sensors and their role in combating cancer through the perception of various aberrant nucleic acids and activation of the immune system. We discuss the connections between different programmed cell death modes and nucleic acid sensors. Finally, we outline the development of nucleic acid sensor agonists, highlighting how their potential as therapeutic targets opens up new avenues for cancer immunotherapy.

Adaptive inhibition of CGAS signaling by TREX1

Mammalian cells react to the accumulation of double-stranded (ds)DNA in the cytosol by secreting antiviral and proinflammatory cytokines, notably type I interferon (IFN). Recent data reported by Tani et al. demonstrate that overactivation of this pathway is prevented by an adaptive feedback mechanism elicited by type I IFN receptors and executed by the exonuclease three prime repair exonuclease 1 (TREX1).