Gut dysbiosis conveys psychological stress to activate LRP5/β-catenin pathway promoting cancer stemness.

Psychological stress causes gut microbial dysbiosis and cancer progression, yet how gut microbiota determines psychological stress-induced tumor development remains unclear. Here we showed that psychological stress promotes breast tumor growth and cancer stemness, an outcome that depends on gut microbiota in germ-free and antibiotic-treated mice. Metagenomic and metabolomic analyses revealed that psychological stress markedly alters the composition and abundance of gut microbiota, especially Akkermansia muciniphila (A. muciniphila), and decreases short-chain fatty acid butyrate. Supplement of active A. muciniphila, butyrate or a butyrate-producing high fiber diet dramatically reversed the oncogenic property and anxiety-like behavior of psychological stress in a murine spontaneous tumor model or an orthotopic tumor model. Mechanistically, RNA sequencing analysis screened out that butyrate decreases LRP5 expression to block the activation of Wnt/β-catenin signaling pathway, dampening breast cancer stemness. Moreover, butyrate as a HDAC inhibitor elevated histone H3K9 acetylation level to transcriptionally activate ZFP36, which further accelerates LRP5 mRNA decay by binding adenine uridine-rich (AU-rich) elements of LRP5 transcript. Clinically, fecal A. muciniphila and serum butyrate were inversely correlated with tumoral LRP5/β-catenin expression, poor prognosis and negative mood in breast cancer patients. Altogether, our findings uncover a microbiota-dependent mechanism of psychological stress-triggered cancer stemness, and provide both clinical biomarkers and potential therapeutic avenues for cancer patients undergoing psychological stress.