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Liu X, Chen Y, Zhang S, Dong L. Gut microbiota-mediated immunomodulation in tumor. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:221. [PMID: 34217349 PMCID: PMC8254267 DOI: 10.1186/s13046-021-01983-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/16/2021] [Indexed: 12/15/2022]
Abstract
Tumor immunity consists of various types of cells, which serve an important role in antitumor therapy. The gastrointestinal tract is colonized by trillions of microorganisms, which form the gut microbiota. In addition to pathogen defense and maintaining the intestinal ecosystem, gut microbiota also plays a pivotal role in various physiological processes. Recently, the association between these symbionts and cancer, ranging from oncogenesis and cancer progression to resistance or sensitivity to antitumor therapies, has attracted much attention. Metagenome analysis revealed a significant difference between the gut microbial composition of cancer patients and healthy individuals. Moreover, modulation of microbiome could improve therapeutic response to immune checkpoint inhibitors (ICIs). These findings suggest that microbiome is involved in cancer pathogenesis and progression through regulation of tumor immunosurveillance, although the exact mechanisms remain largely unknown. This review focuses on the interaction between the microbiome and tumor immunity, with in-depth discussion regarding the therapeutic potential of modulating gut microbiota in ICIs. Further investigations are warranted before gut microbiota can be introduced into clinical practice.
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Affiliation(s)
- Xinyi Liu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200030, People's Republic of China.,Shanghai Medical College of Fudan University, 130 Dongan Road, Shanghai, 200030, People's Republic of China
| | - Yanjie Chen
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200030, People's Republic of China
| | - Si Zhang
- Shanghai Medical College of Fudan University, 130 Dongan Road, Shanghai, 200030, People's Republic of China.
| | - Ling Dong
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200030, People's Republic of China. .,Shanghai Institute of Liver Diseases, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
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52
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D’Alessandro G, Lauro C, Quaglio D, Ghirga F, Botta B, Trettel F, Limatola C. Neuro-Signals from Gut Microbiota: Perspectives for Brain Glioma. Cancers (Basel) 2021; 13:2810. [PMID: 34199968 PMCID: PMC8200200 DOI: 10.3390/cancers13112810] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 12/15/2022] Open
Abstract
Glioblastoma (GBM) is the most aggressive form of glioma tumor in adult brain. Among the numerous factors responsible for GBM cell proliferation and invasion, neurotransmitters such as dopamine, serotonin and glutamate can play key roles. Studies performed in mice housed in germ-free (GF) conditions demonstrated the relevance of the gut-brain axis in a number of physiological and pathological conditions. The gut-brain communication is made possible by vagal/nervous and blood/lymphatic routes and pave the way for reciprocal modulation of functions. The gut microbiota produces and consumes a wide range of molecules, including neurotransmitters (dopamine, norepinephrine, serotonin, gamma-aminobutyric acid [GABA], and glutamate) that reach their cellular targets through the bloodstream. Growing evidence in animals suggests that modulation of these neurotransmitters by the microbiota impacts host neurophysiology and behavior, and affects neural cell progenitors and glial cells, along with having effects on tumor cell growth. In this review we propose a new perspective connecting neurotransmitter modulation by gut microbiota to glioma progression.
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Affiliation(s)
- Giuseppina D’Alessandro
- Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy; (G.D.); (C.L.); (F.T.)
- IRCCS Neuromed, 86077 Pozzilli, IS, Italy
| | - Clotilde Lauro
- Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy; (G.D.); (C.L.); (F.T.)
| | - Deborah Quaglio
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy; (D.Q.); (F.G.); (B.B.)
| | - Francesca Ghirga
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy; (D.Q.); (F.G.); (B.B.)
| | - Bruno Botta
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy; (D.Q.); (F.G.); (B.B.)
| | - Flavia Trettel
- Department of Physiology and Pharmacology, Sapienza University, 00185 Rome, Italy; (G.D.); (C.L.); (F.T.)
| | - Cristina Limatola
- IRCCS Neuromed, 86077 Pozzilli, IS, Italy
- Department of Physiology and Pharmacology, Sapienza University, Laboratory Affiliated to Istituto Pasteur Italia, 00185 Rome, Italy
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53
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Tritz ZP, Ayasoufi K, Johnson AJ. Anti-PD-1 checkpoint blockade monotherapy in the orthotopic GL261 glioma model: the devil is in the detail. Neurooncol Adv 2021; 3:vdab066. [PMID: 34151268 PMCID: PMC8209580 DOI: 10.1093/noajnl/vdab066] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The GL261 cell line, syngeneic on the C57BL/6 background, has, since its establishment half a century ago in 1970, become the most commonly used immunocompetent murine model of glioblastoma. As immunotherapy has entered the mainstream of clinical discourse in the past decade, this model has proved its worth as a formidable opponent against various immunotherapeutic combinations. Although advances in surgical, radiological, and chemotherapeutic interventions have extended mean glioblastoma patient survival by several months, 5-year survival postdiagnosis remains below 5%. Immunotherapeutic interventions, such as the ones explored in the murine GL261 model, may prove beneficial for patients with glioblastoma. However, even common immunotherapeutic interventions in the GL261 model still have unclear efficacy, with wildly discrepant conclusions being made in the literature regarding this topic. Here, we focus on anti-PD-1 checkpoint blockade monotherapy as an example of this pattern. We contend that a fine-grained analysis of how biological variables (age, sex, tumor location, etc.) predict treatment responsiveness in this preclinical model will better enable researchers to identify glioblastoma patients most likely to benefit from checkpoint blockade immunotherapy moving forward.
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Affiliation(s)
- Zachariah P Tritz
- Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Aaron J Johnson
- Department of Immunology, Mayo Clinic, Rochester, Minnesota, USA
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
- Corresponding Author: Aaron J. Johnson, PhD, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA ()
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54
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Lyu Y, Yang H, Chen L. Metabolic regulation on the immune environment of glioma through gut microbiota. Semin Cancer Biol 2021; 86:990-997. [PMID: 33971263 DOI: 10.1016/j.semcancer.2021.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/08/2021] [Accepted: 05/04/2021] [Indexed: 12/12/2022]
Abstract
The gut-brain axis has paved our way in understanding varieties of disease. The gut microbiota especially the bacterial population plays critical roles in immune system development and function. Glioma comprises 80 percent of malignant brain cancer and glioblastoma (GBM) is the most malignant kind. GBM has a reputation for its suppressive immune environment and poor patient prognosis. Moreover, altered metabolites from gut microbiota affect both systemic immune and central nervous system (CNS) immunity. Here we will focus on the crosstalk between gut microbiota and GBM, and further explore how this communication contributes to glioma initiation and development. Finally, we highlight the latest insights on the metabolic regulation of immunity through gut microbiota, which provides a promising therapeutic strategy for GBM.
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Affiliation(s)
- Yingying Lyu
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Hui Yang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, PR China; Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, PR China; Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, PR China.
| | - Liang Chen
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, PR China; Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, PR China.
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55
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Li XC, Wu BS, Jiang Y, Li J, Wang ZF, Ma C, Li YR, Yao J, Jin XQ, Li ZQ. Temozolomide-Induced Changes in Gut Microbial Composition in a Mouse Model of Brain Glioma. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:1641-1652. [PMID: 33907383 PMCID: PMC8071088 DOI: 10.2147/dddt.s298261] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/07/2021] [Indexed: 12/15/2022]
Abstract
Background Gut microbiota is associated with the progression of brain tumors. However, the alterations in gut microbiota observed during glioma growth and temozolomide (TMZ) therapy remain poorly understood. Methods C57BL/6 male mice were implanted with GL261 glioma cells. TMZ/sodium carboxymethyl cellulose (SCC) was administered through gavage for five consecutive days (from 8 to 12 days after implantation). Fecal samples were collected before (T0) and on days 7 (T1), 14 (T2), and 28 (T3) after implantation. The gut microbiota was analyzed using 16S ribosomal DNA sequencing followed by absolute and relative quantitation analyses. Results Nineteen genera were altered during glioma progression with the most dramatic changes in Firmicutes and Bacteroidetes phyla. During glioma growth, Lactobacillus abundance decreased in the early stage (T1) and then gradually increased (T2, T3); Intestinimonas abundance exhibited a persistent increase; Anaerotruncus showed a transient increase (T2) and then a subsequent decrease (T3). Similar longitudinal changes in Intestinimonas and Anaerotruncus abundance were observed in TMZ-treated mice, but the decrease of Anaerotruncus at T3 in the TMZ-treated group was less than that in the vehicle-treated group. No significant change in Lactobacillus was observed after TMZ treatment. Additionally, compared to vehicle control, TMZ treatment led to an enrichment in Akkermansia and Bifidobacterium. Conclusion Glioma development and progression altered the composition of gut microbiota. Induction of Akkermansia and Bifidobacterium as well as the prevention of the reduction in Anaerotruncus may contribute to the anti-tumor effect of TMZ. This study helps to reveal the association between levels of specific microbial species in the gut and the anti-tumor effect of TMZ.
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Affiliation(s)
- Xiao-Chong Li
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Bang-Sheng Wu
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China.,Second Clinical School, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Yi Jiang
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China.,Second Clinical School, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Jie Li
- Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, People's Republic of China
| | - Ze-Fen Wang
- Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, People's Republic of China
| | - Chao Ma
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Yi-Rong Li
- Department of Clinical Laboratory, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Jie Yao
- Department of Biological Repositories, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Xiao-Qing Jin
- Emergency Department, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
| | - Zhi-Qiang Li
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University, Wuhan, 430071, Hubei, People's Republic of China
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Jain T, Sharma P, Are AC, Vickers SM, Dudeja V. New Insights Into the Cancer-Microbiome-Immune Axis: Decrypting a Decade of Discoveries. Front Immunol 2021; 12:622064. [PMID: 33708214 PMCID: PMC7940198 DOI: 10.3389/fimmu.2021.622064] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/11/2021] [Indexed: 12/13/2022] Open
Abstract
The past decade has witnessed groundbreaking advances in the field of microbiome research. An area where immense implications of the microbiome have been demonstrated is tumor biology. The microbiome affects tumor initiation and progression through direct effects on the tumor cells and indirectly through manipulation of the immune system. It can also determine response to cancer therapies and predict disease progression and survival. Modulation of the microbiome can be harnessed to potentiate the efficacy of immunotherapies and decrease their toxicity. In this review, we comprehensively dissect recent evidence regarding the interaction of the microbiome and anti-tumor immune machinery and outline the critical questions which need to be addressed as we further explore this dynamic colloquy.
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Affiliation(s)
| | | | | | - Selwyn M. Vickers
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Vikas Dudeja
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, United States
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57
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Ciernikova S, Mego M, Chovanec M. Exploring the Potential Role of the Gut Microbiome in Chemotherapy-Induced Neurocognitive Disorders and Cardiovascular Toxicity. Cancers (Basel) 2021; 13:782. [PMID: 33668518 PMCID: PMC7918783 DOI: 10.3390/cancers13040782] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023] Open
Abstract
Chemotherapy, targeting not only malignant but also healthy cells, causes many undesirable side effects in cancer patients. Due to this fact, long-term cancer survivors often suffer from late effects, including cognitive impairment and cardiovascular toxicity. Chemotherapy damages the intestinal mucosa and heavily disrupts the gut ecosystem, leading to gastrointestinal toxicity. Animal models and clinical studies have revealed the associations between intestinal dysbiosis and depression, anxiety, pain, impaired cognitive functions, and cardiovascular diseases. Recently, a possible link between chemotherapy-induced gut microbiota disruption and late effects in cancer survivors has been proposed. In this review, we summarize the current understanding of preclinical and clinical findings regarding the emerging role of the microbiome and the microbiota-gut-brain axis in chemotherapy-related late effects affecting the central nervous system (CNS) and heart functions. Importantly, we provide an overview of clinical trials evaluating the relationship between the gut microbiome and cancer survivorship. Moreover, the beneficial effects of probiotics in experimental models and non-cancer patients with neurocognitive disorders and cardiovascular diseases as well as several studies on microbiota modulations via probiotics or fecal microbiota transplantation in cancer patients are discussed.
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Affiliation(s)
- Sona Ciernikova
- Department of Genetics, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
| | - Michal Mego
- 2nd Department of Oncology, Faculty of Medicine, Comenius University, Bratislava and National Cancer Institute, 833 10 Bratislava, Slovakia; (M.M.); (M.C.)
| | - Michal Chovanec
- 2nd Department of Oncology, Faculty of Medicine, Comenius University, Bratislava and National Cancer Institute, 833 10 Bratislava, Slovakia; (M.M.); (M.C.)
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58
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Dees KJ, Koo H, Humphreys JF, Hakim JA, Crossman DK, Crowley MR, Nabors LB, Benveniste EN, Morrow CD, McFarland BC. Human gut microbial communities dictate efficacy of anti-PD-1 therapy in a humanized microbiome mouse model of glioma. Neurooncol Adv 2021; 3:vdab023. [PMID: 33758825 PMCID: PMC7967908 DOI: 10.1093/noajnl/vdab023] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Although immunotherapy works well in glioblastoma (GBM) preclinical mouse models, the therapy has not demonstrated efficacy in humans. To address this anomaly, we developed a novel humanized microbiome (HuM) model to study the response to immunotherapy in a preclinical mouse model of GBM. Methods We used 5 healthy human donors for fecal transplantation of gnotobiotic mice. After the transplanted microbiomes stabilized, the mice were bred to generate 5 independent humanized mouse lines (HuM1-HuM5). Results Analysis of shotgun metagenomic sequencing data from fecal samples revealed a unique microbiome with significant differences in diversity and microbial composition among HuM1-HuM5 lines. All HuM mouse lines were susceptible to GBM transplantation, and exhibited similar median survival ranging from 19 to 26 days. Interestingly, we found that HuM lines responded differently to the immune checkpoint inhibitor anti-PD-1. Specifically, we demonstrate that HuM1, HuM4, and HuM5 mice are nonresponders to anti-PD-1, while HuM2 and HuM3 mice are responsive to anti-PD-1 and displayed significantly increased survival compared to isotype controls. Bray-Curtis cluster analysis of the 5 HuM gut microbial communities revealed that responders HuM2 and HuM3 were closely related, and detailed taxonomic comparison analysis revealed that Bacteroides cellulosilyticus was commonly found in HuM2 and HuM3 with high abundances. Conclusions The results of our study establish the utility of humanized microbiome mice as avatars to delineate features of the host interaction with gut microbial communities needed for effective immunotherapy against GBM.
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Affiliation(s)
- Kory J Dees
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hyunmin Koo
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - J Fraser Humphreys
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Joseph A Hakim
- School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David K Crossman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Michael R Crowley
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - L Burton Nabors
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Etty N Benveniste
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Casey D Morrow
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Braden C McFarland
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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59
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Abstract
Diagnosis and treatment of disease demand a sound understanding of the underlying mechanisms, determining any Achilles' heel that can be targeted in effective therapies. Throughout history, this endeavour to decipher the origin and mechanism of transformation of a normal cell into cancer has led to various theories-from cancer as a curse to an understanding at the level of single-cell heterogeneity, meaning even among a single sub-type of cancer there are myriad molecular challenges to overcome. With increasing insight into cancer genetics and biology, the disease has become ever more complex to understand. The complexity of cancer as a disease was distilled into key traits by Hanahan and Weinberg in their seminal 'Hallmarks of Cancer' reviews. This lucid conceptualization of complex cancer biology is widely accepted and has helped advance cancer therapeutics by targeting the various hallmarks but, with the advancement in technologies, there is greater granularity in how we view cancer as a disease, and the additional understanding over the past decade requires us to revisit the hallmarks of cancer. Based on extensive study of the cancer research literature, we propose four novel hallmarks of cancer, namely, the ability of cells to regress from a specific specialized functional state, epigenetic changes that can affect gene expression, the role of microorganisms and neuronal signalling, to be included in the hallmark conceptualization along with evidence of various means to exploit them therapeutically.
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Affiliation(s)
- Sasi S. Senga
- Centre for Tumour Biology, Barts Cancer Institute, Queen
Mary University of London, London EC1M
6BQ, UK
| | - Richard P. Grose
- Centre for Tumour Biology, Barts Cancer Institute, Queen
Mary University of London, London EC1M
6BQ, UK
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60
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Ratnam NM, Frederico SC, Gonzalez JA, Gilbert MR. Clinical correlates for immune checkpoint therapy: significance for CNS malignancies. Neurooncol Adv 2021; 3:vdaa161. [PMID: 33506203 PMCID: PMC7813206 DOI: 10.1093/noajnl/vdaa161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Immune checkpoint inhibitors (ICIs) have revolutionized the field of cancer immunotherapy. Most commonly, inhibitors of PD-1 and CTLA4 are used having received approval for the treatment of many cancers like melanoma, non-small-cell lung carcinoma, and leukemia. In contrast, to date, clinical studies conducted in patients with CNS malignancies have not demonstrated promising results. However, patients with CNS malignancies have several underlying factors such as treatment with supportive medications like corticosteroids and cancer therapies including radiation and chemotherapy that may negatively impact response to ICIs. Although many clinical trials have been conducted with ICIs, measures that reproducibly and reliably indicate that treatment has evoked an effective immune response have not been fully developed. In this article, we will review the history of ICI therapy and the correlative biology that has been performed in the clinical trials testing these therapies in different cancers. It is our aim to help provide an overview of the assays that may be used to gauge immunologic response. This may be particularly germane for CNS tumors, where there is currently a great need for predictive biomarkers that will allow for the selection of patients with the highest likelihood of responding.
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Affiliation(s)
- Nivedita M Ratnam
- Neuro-Oncology Branch, CCR, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Stephen C Frederico
- Neuro-Oncology Branch, CCR, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Javier A Gonzalez
- Neuro-Oncology Branch, CCR, NCI, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark R Gilbert
- Neuro-Oncology Branch, CCR, NCI, National Institutes of Health, Bethesda, Maryland, USA
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61
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Abstract
The innate immune system in the central nervous system (CNS) is mainly represented by specialized tissue-resident macrophages, called microglia. In the past years, various species-, host- and tissue-specific as well as environmental factors were recognized that essentially affect microglial properties and functions in the healthy and diseased brain. Host microbiota are mostly residing in the gut and contribute to microglial activation states, for example, via short-chain fatty acids (SCFAs) or aryl hydrocarbon receptor (AhR) ligands. Thereby, the gut microorganisms are deemed to influence numerous CNS diseases mediated by microglia. In this review, we summarize recent findings of the interaction between the host microbiota and the CNS in health and disease, where we specifically highlight the resident gut microbiota as a crucial environmental factor for microglial function as what we coin "the microbiota-microglia axis."
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Affiliation(s)
- Omar Mossad
- Institute of NeuropathologyFaculty of MedicineUniversity of FreiburgFreiburgGermany
- Faculty of BiologyUniversity of FreiburgFreiburgGermany
| | - Daniel Erny
- Institute of NeuropathologyFaculty of MedicineUniversity of FreiburgFreiburgGermany
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