Intratumor microbiome: selective colonization in the tumor microenvironment and a vital regulator of tumor biology

Abstract

The polymorphic microbiome has been proposed as a new hallmark of cancer. Intratumor microbiome has been revealed to play vital roles in regulating tumor initiation and progression, but the regulatory mechanisms have not been fully uncovered. In this review, we illustrated that similar to other components in the tumor microenvironment, the reside and composition of intratumor microbiome are regulated by tumor cells and the surrounding microenvironment. The intratumor hypoxic, immune suppressive, and highly permeable microenvironment may select certain microbiomes, and tumor cells may directly interact with microbiome via molecular binding or secretions. Conversely, the intratumor microbiomes plays vital roles in regulating tumor initiation and progression via regulating the mutational landscape, the function of genes in tumor cells and modulating the tumor microenvironment, including immunity, inflammation, angiogenesis, stem cell niche, etc. Moreover, intratumor microbiome is regulated by anti‐cancer therapies and actively influences therapy response, which could be a therapeutic target or engineered to be a therapy weapon in the clinic. This review highlights the intratumor microbiome as a vital component in the tumor microenvironment, uncovers potential mutual regulatory mechanisms between the tumor microenvironment and intratumor microbiome, and points out the ongoing research directions and drawbacks of the research area, which should broaden our view of microbiome and enlighten further investigation directions.

Enterosorption may contribute to the reactivation of anticancer immunity and be an effective approach to tumor growth control

“…When global systemic immunosuppression or immunological tolerance is formed as a result of the accumulation in the body of toxic biologically active tumor products this can lead to uncontrolled growth of pathogenic and opportunistic gut microbiota which also becomes pathogenic. In turn, this pathogenic microbiota may promote both the acceleration of tumor growth and the further increase the local and systemic immunosuppression and tumor-specific tolerance ( 19 – 24 , 32 , 35 ).…”

Bacteriophages Therapy: Exploring Their Promising Role in Microbiome Modulation and Combatting Antibiotic Resistance

“…Phage therapy, the therapeutic use of bacteriophages to target pathogenic bacteria, is being explored as an alternative to traditional antibiotics. By selectively targeting harmful bacteria while leaving beneficial ones intact, phage therapy holds promise for treating bacterial infections with reduced ecological disruption to the microbiome [48][49][50].…”