Fusobacterium nucleatum, inflammation, and immunity: the fire within human gut

Abstract

Fusobacterium nucleatum is an identified proinflammatory autochthonous bacterium implicated in human colorectal cancer. It is also abundantly found in patients suffering from chronic gut inflammation (inflammatory bowel disease), consequently contributing to the pathogenesis of colorectal cancer. Majority of the studies have reported that colorectal tumors/colorectal adenocarcinomas are highly enriched with F. nucleatum compared to noninvolved adjacent colonic tissue. During the course of multistep development of colorectal cancer, tumors have evolved many mechanisms to resist the antitumor immune response. One of such favorite ploy is providing access to pathogenic bacteria, especially F. nucleatum in the colorectal tumor microenvironment, wherein both (colorectal tumors and F. nucleatum) exert profound effect on each other, consequently attracting tumor-permissive myeloid-derived suppressor cells, suppressing cytotoxic CD8+ T cells and inhibiting NK cell-mediated cancer cell killing. In this review, we have primarily focused on how this bug modulates the immune response, consequently rendering the antitumor immune cells inactive.

TLR2/TLR4 activation induces Tregs and suppresses intestinal inflammation caused by Fusobacterium nucleatum in vivo

“…Many studies have also reported that F . nucleatum induced proinflammatory cytokines through different pathways [19–20]. However, in the present study, it is first proposed that TLR2/TLR4 regulate F .…”

Fusobacterium nucleatum-Induced Impairment of Autophagic Flux Enhances the Expression of Proinflammatory Cytokines via ROS in Caco-2 Cells

“…nucleatum infection could induce inflammation in different cells, including gingival epithelial cells and macrophage [26–27]. To clarify the role of F .…”

Tea polyphenols inhibit the growth and virulence properties of Fusobacterium nucleatum

“…F. nucleatum can also be isolated from extra-oral infections and has been associated with inflammatory bowel disease and colorectal cancer11121314. In a previous study24, we used a macrophage model to show that tea polyphenols, including EGCG and theaflavins, can attenuate the inflammatory response induced by F. nucleatum .…”

“…F. nucleatum is also a common resident of the human gastrointestinal tract12. Over the past few years, several studies have shown that this bacterial species increases in numbers in patients affected with inflammatory bowel disease and may contribute to the pathogenesis of colorectal cancer121314.…”