Integrated microbiome-metabolome analysis implicates Acinetobacter guillouiae in arachidonic acid metabolic remodeling and endometrial cancer cell proliferation

BACKGROUND: Lesion-associated microbiota have emerged as potential regulators of tumor biology. However, the ecological organization and metabolic relevance of the local endometrial microbiome in endometrial cancer (EC) remain incompletely defined. This study aimed to characterize microbiome-associated metabolic alterations in EC tissues. METHODS: We performed integrated 16S rRNA sequencing and untargeted metabolomic analyses using paired EC and adjacent non-tumor endometrial tissues. Microbial diversity, taxonomic composition, co-occurrence network architecture, and metabolomic pathway alterations were evaluated. Conditioned medium derived from Acinetobacter guillouiae was used to explore its association with arachidonic acid (AA) metabolism and proliferative phenotypes in EC cells, followed by pharmacological pathway interrogation and xenograft validation. RESULTS: Overall microbial diversity was not significantly different between EC and adjacent tissues, whereas EC tissues exhibited a more connected and centralized microbial co-occurrence network. Taxonomic analyses identified enrichment of A. guillouiae in EC tissues based on 16S rRNA taxonomic assignment. Untargeted metabolomics revealed a group-level metabolic shift in EC tissues, with AA metabolism among the most prominently enriched pathways. In EC cells, A. guillouiae-derived conditioned medium increased intracellular AA levels, enhanced cPLA2 phosphorylation, induced AA-metabolizing enzymes, and activated the TLR4/NF-κB/ALOX5 signaling axis. Pharmacological inhibition of cPLA2, ALOX5, TLR4, or NF-κB partially attenuated the metabolic or proliferative effects associated with A. guillouiae conditioned medium. In a xenograft model, intratumoral exposure to A. guillouiae was associated with accelerated tumor growth. CONCLUSIONS: These findings suggest that A. guillouiae-associated microbial alterations may contribute to AA metabolic remodeling and proliferative phenotypes in EC. This study provides a microbiome-metabolome framework for understanding lipid metabolic heterogeneity in EC and supports further validation of bacteria-associated AA metabolism as a potential therapeutic target.