Dietary Urolithin B Suppresses Lung Tumorigenesis Correlating with Autophagy Induction and Gut Microbiota Remodeling.

[BACKGROUND] Urolithin B (UB) is a gut microbial metabolite derived from dietary ellagitannins found in foods such as pomegranates, berries, and nuts. Although UB has demonstrated antitumor potential, possibly through gut microbiota modulation, its specific role and underlying mechanisms in lung cancer remain unclear.

[OBJECTIVES] This study aimed to investigate the antitumor effects of UB on lung cancer suppression and to explore the potential involvement of autophagy and gut microbiota in these effects.

[METHODS] We employed in vitro and in vivo approaches. Lung cancer cells were treated with UB at varying concentrations to assess proliferation and autophagy. Transcriptomic analysis was conducted to identify key regulatory pathways. A tumor-bearing mouse model was used to evaluate the effects of oral UB administration, and gut microbiota changes were analyzed via 16S rRNA sequencing.

[RESULTS] UB inhibited lung cancer cell growth in a dose- and time-dependent manner, primarily by inducing autophagy rather than apoptosis, as evidenced by increased microtubule-associated protein 1A/1B-light chain 3-II concentrations. Transcriptomic profiling and protein analysis revealed that UB treatment was associated with a change in the status of the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathway, a key regulator of autophagy. In vivo, oral UB administration significantly suppressed tumor growth, enhanced autophagic activity, and modulated the expression of autophagy-related proteins. Furthermore, 16S rRNA sequencing revealed that UB induced an enrichment of beneficial gut bacteria, including Lactobacillus and Desulfovibrio.

[CONCLUSIONS] These findings highlight UB as a promising dietary-derived metabolite for lung cancer prevention and therapy. Our study suggests that UB exerts its antitumor effects in part through the induction of autophagy associated with the AMPK/mTOR pathway and concomitant modulation of the gut microbiota, emphasizing the critical role of food-gut interactions in cancer management.