cGAS/STING axis mediates a topoisomerase II inhibitor–induced tumor immunogenicity

Checkpoint blockade antibodies have been approved as immunotherapy for multiple types of cancer, but the response rate and efficacy are still limited. There are few immunogenic cell death–inducing (ICD-inducing) drugs available that can kill cancer cells, enhance tumor immunogenicity, increase in vivo immune infiltration, and thereby boost a tumor response to immunotherapy. So far, the ICD markers have been identified as the few immunostimulating characteristics of dead cells, but whether the presence of such ICD markers on tumor cells translates into enhanced antitumor immunity in vivo is still being investigated. To identify anticancer drugs that could induce tumor cell death and boost T cell response, we performed drug screenings based on both an ICD reporter assay and a T cell activation assay. We showed that teniposide, a DNA topoisomerase II inhibitor, could induce high-mobility group box 1 (HMGB1) release and type I IFN signaling in tumor cells and that teniposide-treated tumor cells could activate antitumor T cell response both in vitro and in vivo. Mechanistically, teniposide induced tumor cell DNA damage and innate immune signaling, including NF-κB activation and stimulator of IFN genes–dependent (STING-dependent) type I IFN signaling, both of which contribute to the activation of dendritic cells and subsequent T cells. Furthermore, teniposide potentiated the antitumor efficacy of anti-PD1 in multiple types of mouse tumor models. Our findings showe...
Source: Journal of Clinical Investigation - Category: Biomedical Science Authors: Source Type: research

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Publication date: 29 October 2019Source: Cell Reports, Volume 29, Issue 5Author(s): Linda Schadt, Colin Sparano, Nicole Angelika Schweiger, Karina Silina, Virginia Cecconi, Giulia Lucchiari, Hideo Yagita, Emilien Guggisberg, Sascha Saba, Zuzana Nascakova, Winfried Barchet, Maries van den BroekSummarySensing of cytoplasmic DNA by cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) results in production of the dinucleotide cGAMP and consecutive activation of stimulator of interferon genes (STING) followed by production of type I interferon (IFN). Although cancer cells contain supra-normal conc...
Source: Cell Reports - Category: Cytology Source Type: research
In conclusion, a polypharmacology approach of combining established, prolongevity drug inhibitors of specific nodes may be the most effective way to target the nutrient-sensing network to improve late-life health. Deletion of p38α in Neurons Slows Neural Stem Cell Decline and Loss of Cognitive Function in Mice https://www.fightaging.org/archives/2019/10/deletion-of-p38%ce%b1-in-neurons-slows-neural-stem-cell-decline-and-loss-of-cognitive-function-in-mice/ Researchers here provide evidence for p38α to be involved in the regulation of diminished neural stem cell activity with age. It is thought...
Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
AbstractIn the past decade, remarkable progress has been made in immunotherapy against cancer. Specifically, the introduction of immune checkpoint inhibitors has revolutionized the field. However, many patients are unable to benefit significantly from this treatment option. One of the major reasons for this is most likely the absence of an adequate tumor-specific T cell response in these patients. A way to circumvent this problem might be to combine immune checkpoint inhibitor treatment with new strategies to activate tumor-specific T cells. One such  strategy could be to activate and mature dendritic cells in situ. D...
Source: Cancer Immunology, Immunotherapy - Category: Cancer & Oncology Source Type: research
ConclusionsThese results support combining α-PD-1 therapy with induction of IFN-α/β signaling via provision of STING agonist and/or through CTLA-4 blockade as potential treatment option for HNSCC patients, especially, those not responding to α-PD-1 monotherapy.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
ConclusionLocalized TLR7/8 agonism can enhance recruitment and activation of immune cells in tumors and polarize anti-tumor immunity towards a Th1 response. Moreover, we demonstrate that the anti-tumor effects of this TLR7/8 agonist can be enhanced through combination with checkpoint inhibitors and co-stimulatory agonists.
Source: Journal for Immunotherapy of Cancer - Category: Cancer & Oncology Source Type: research
The stimulator of IFN genes (STING) signaling pathway is a critical link between innate and adaptive immunity and induces antitumor immune responses. STING is expressed in vasculatures, but its role in tumor angiogenesis has not been elucidated. Here, we investigated STING-induced tumor vascular remodeling and the potential of STING-based combination immunotherapy. Endothelial STING expression was correlated with enhanced T cell infiltration and prolonged survival in human colon and breast cancer. Intratumoral STING activation with STING agonists (cGAMP or RR-CDA) normalized tumor vasculatures in implanted and spontaneous ...
Source: Journal of Clinical Investigation - Category: Biomedical Science Authors: Source Type: research
Contributors : Rutger D Luteijn ; Shivam A Zaver ; Benjamin G Gowen ; Stacia Wyman ; Nick Garelis ; Liberty Onia ; Sarah M McWhirter ; George E Katibah ; Jacob E Corn ; Joshua J Woodward ; David H RauletSeries Type : OtherOrganism : Homo sapiensThe accumulation of DNA in the cytosol serves as a key immunostimulatory signal associated with infections, cancer and genomic damage. Cytosolic DNA triggers immune responses by activating the cGAS/STING pathway. The binding of DNA to the cytosolic enzyme cGAMP synthase (cGAS), activates its enzymatic activity, leading to the synthesis of a second messenger, cyclic[G(2 ’,5&rsq...
Source: GEO: Gene Expression Omnibus - Category: Genetics & Stem Cells Tags: Other Homo sapiens Source Type: research
Authors: Gilmore E, McCabe N, Kennedy RD, Parkes EE Abstract Historically the development of anticancer treatments has been focused on their effect on tumor cells alone. However, newer treatments have shifted attention to targets on immune cells, resulting in dramatic responses. The effect of DNA repair deficiency on the microenvironment remains an area of key interest. Moreover, established therapies such as DNA damaging treatments such as chemotherapy and PARP inhibitors further modify the tumor microenvironment. Here we describe DNA repair pathways in breast cancer and activation of innate immune pathways in DNA...
Source: Journal of Oncology - Category: Cancer & Oncology Tags: J Oncol Source Type: research
In this study, we identify a link between members of the genus Veillonella and exercise performance. We observed an increase in Veillonella relative abundance in marathon runners postmarathon and isolated a strain of Veillonella atypica from stool samples. Inoculation of this strain into mice significantly increased exhaustive treadmill run time. Veillonella utilize lactate as their sole carbon source, which prompted us to perform a shotgun metagenomic analysis in a cohort of elite athletes, finding that every gene in a major pathway metabolizing lactate to propionate is at higher relative abundance postexercise. Us...
Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
Mirjolet Historically, the 4Rs and then the 5Rs of radiobiology explained the effect of radiation therapy (RT) fractionation on the treatment efficacy. These 5Rs are: Repair, Redistribution, Reoxygenation, Repopulation and, more recently, intrinsic Radiosensitivity. Advances in radiobiology have demonstrated that RT is able to modify the tumor micro environment (TME) and to induce a local and systemic (abscopal effect) immune response. Conversely, RT is able to increase some immunosuppressive barriers, which can lead to tumor radioresistance. Fractionation and dose can affect the immunomodulatory properties of RT. He...
Source: Cancers - Category: Cancer & Oncology Authors: Tags: Review Source Type: research
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