Histone Lactylation Mediated by circRNA-Facilitated FXR1 Phase Separation Promotes Colorectal Cancer Progression.

Histone lactylation is an epigenetic modification triggered by lactate produced during glycolysis. In cancer, histone lactylation can coordinate metabolic and epigenetic states to promote tumor development and progression. Here, we identified circ2891 as a driver of metabolic reprogramming and histone lactylation in colorectal cancer (CRC). In patients, circ2891 was aberrantly upregulated in tumors and correlated with poor outcomes. Elevated circ2891 potentiated aerobic glycolysis and lactate production in CRC cells, supporting enhanced cell proliferation and tumor growth. Mechanistically, circ2891 specifically interacted with the m6A reader FXR1 and facilitated its phase separation, which stabilized PGK1 and ENO1 mRNAs by enhancing the recognition of their m6A modification sites. Consequently, elevated PGK1 and ENO1 led to increased aerobic glycolysis and drove histone lactylation, thereby transcriptionally activating the RNA helicase DDX21 to promote CRC progression. Simultaneously targeting circ2891 and histone lactylation suppressed patient-derived organoid and xenograft tumor growth. Together, these findings show that circ2891 promotes CRC by stabilizing PGK1/ENO1 via phase separation of FXR1, boosting glycolysis and histone lactylation to activate expression of DDX21. Targeting circ2891 offers a promising therapeutic strategy enhancing clinical outcomes.