The crosstalk between the gut microbiota and tumor immunity: Implications for cancer progression and treatment outcomes

Abstract

The gastrointestinal tract is inhabited by trillions of commensal microorganisms that constitute the gut microbiota. As a main metabolic organ, the gut microbiota has co-evolved in a symbiotic relationship with its host, contributing to physiological homeostasis. Recent advances have provided mechanistic insights into the dual role of the gut microbiota in cancer pathogenesis. Particularly, compelling evidence indicates that the gut microbiota exerts regulatory effects on the host immune system to fight against cancer development. Some microbiota-derived metabolites have been suggested as potential activators of antitumor immunity. On the contrary, the disequilibrium of intestinal microbial communities, a condition termed dysbiosis, can induce cancer development. The altered gut microbiota reprograms the hostile tumor microenvironment (TME), thus allowing cancer cells to avoid immunosurvelliance. Furthermore, the gut microbiota has been associated with the effects and complications of cancer therapy given its prominent immunoregulatory properties. Therapeutic measures that aim to manipulate the interplay between the gut microbiota and tumor immunity may bring new breakthroughs in cancer treatment. Herein, we provide a comprehensive update on the evidence for the implication of the gut microbiota in immune-oncology and discuss the fundamental mechanisms underlying the influence of intestinal microbial communities on systemic cancer therapy, in order to provide important clues toward improving treatment outcomes in cancer patients.

The relationship between gut and nasopharyngeal microbiome composition can predict the severity of COVID-19

“…In the present study, in both nasopharyngeal swabs and stools, every group of patients presented distinctly differentiated clusters. As previously reported, COVID-19 disease severity is more dependent on the presence or absence of certain bacteria rather than alterations in bacterial diversity and richness [14,53]. Supporting this, characterization of bacterial microbiota composition at phyla and genera levels for nasopharyngeal and stool samples indicated a more evident association between changes on them and the severity of the disease.…”

Eliminating COVID‐19 as the immediate culprit for igniting pancreatitis

“…Intestinal barrier impairment, dysbiosis of gut microbiota, and perturbation of metabolites are prevalent occurrences among individuals with COVID‐19. Extensive research has consistently shown the association between microbiota composition and the morbidity, exacerbation, and mortality rates seen in COVID‐19 patients 51–55 . The gut microbiota facilitates the assessment of sickness severity in individuals with COVID‐19 56 .…”

“…patients. [51][52][53][54][55] The gut microbiota facilitates the assessment of sickness severity in individuals with COVID-19. 56 From a mechanical standpoint, it is observed that COVID-19 disrupts the composition of gut microbiota and metabolites.…”

Alterations in microbiota of patients with COVID‐19: implications for therapeutic interventions

“…The bidirectional regulation between the gut microbiota and host immunity may play an important role in this process. 109 In addition, SARS-CoV-2 may cause the disorder of gut microbiota, thereby increasing susceptibility to COVID-19. The mechanisms by which the disturbance of gut microbiota increases susceptibility to COVID-19 and associated symptoms are poorly understood.…”

“…Subsequently, related bacteria produce bioactive metabolites, inflammatory factor responses, and changes in the immune microenvironment, which may promote the progression of COVID‐19. The bidirectional regulation between the gut microbiota and host immunity may play an important role in this process 109 . In addition, SARS‐CoV‐2 may cause the disorder of gut microbiota, thereby increasing susceptibility to COVID‐19.…”