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Inosine, Gut Microbiota, and Cancer Immunometabolism Publisher Pubmed



Samami E1, 2 ; Aleebrahimdehkordi E3, 4, 6 ; Mohebalizadeh M4, 5, 6 ; Yaribash S7, 8 ; Saghazadeh A8, 9 ; Rezaei N4, 6, 9, 10
Authors
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Authors Affiliations
  1. 1. Cancer Immunology Project (CIP), Universal Scientific Education and Research Network (USERN), Tehran, Iran
  2. 2. Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
  3. 3. Medical Plants Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Iran
  4. 4. Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Iran
  5. 5. Student Research Committee, Urmia University of Medical Sciences, Iran
  6. 6. Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Iran
  7. 7. School of Pharmacy, Tehran University of Medical Sciences, International Campus, Tehran, Iran
  8. 8. Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
  9. 9. Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
  10. 10. Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

Source: American journal of physiology. Endocrinology and metabolism Published:2023


Abstract

This article briefly reviews cancer immunity and the role of gut microbiota in carcinogenesis, followed by an understanding of mechanisms by which inosine is involved in cancer immunometabolism. The immune system plays a paradoxical role in cancer treatment. Antitumor immunity depends on the T-cell priming against tumor antigens, whereas inflammatory mediators trigger the protumor signaling in the tumor microenvironment. Studies link the microbiome with metabolism and immunity-two main factors implicated in carcinogenesis. Gut microbiota has been shown to affect both antitumor immunity and protumor immune signaling. There is mounting evidence that the human microbiome can play a role in the immunotherapeutic effects, both response and resistance. Inosine-5'-monophosphate dehydrogenase (IMPDH) is a highly conservative enzyme widely expressed in mammals. Cell signaling pathways use molecular inosine, a crucial secondary metabolite in purine metabolism and a molecular messenger. Recent research has identified inosine as a critical regulator of immune checkpoint inhibition (ICI) therapeutic response in various tumor types. Some bacterial species were found to produce inosine or its metabolite hypoxanthine and induce T-helper 1 differentiation and effector functions via the inosine-A2AR-cAMP-PKA pathway upon ICI therapy. Also, inosine acts as a substitute carbon source for T-cell metabolism in glucose-restricted environments, i.e., the tumor microenvironment, assisting T-cell proliferation and differentiation while enhancing sensitivity to ICI, reinforcing the notion that inosine metabolism might contribute to antitumor immunity. Also, inosine is a potent agonist of the adenosine receptor, A2AR, and A2AR signaling can affect T-cell responses and antitumor immunity, making the inosine-A2AR pathway blockage a candidate for cancer treatment. Further research is required to investigate inosine as a cancer immunometabolism therapy.