Lactylome Analysis Unveils Lactylation-Dependent Mechanisms of Stemness Remodeling in the Liver Cancer Stem Cells

Lactate plays a critical role as an energy substrate, metabolite, and signaling molecule in hepatocellular carcinoma (HCC). Intracellular lactate-derived protein lysine lactylation (Kla) is identified as a contributor to the progression of HCC. Liver cancer stem cells (LCSCs) are believed to be the root cause of phenotypic and functional heterogeneity in HCC. However, the impact of Kla on the biological processes of LCSCs remains poorly understood. Here enhanced glycolytic metabolism, lactate accumulation, and elevated levels of lactylation are observed in LCSCs compared to HCC cells. H3K56la was found to be closely associated with tumourigenesis and stemness of LCSCs. Notably, a comprehensive examination of the lactylome and proteome of LCSCs and HCC cells identified the ALDOA K230/322 lactylation, which plays a critical role in promoting the stemness of LCSCs. Furthermore, this study demonstrated the tight binding between aldolase A (ALDOA) and dead box deconjugate enzyme 17 (DDX17), which is attenuated by ALDOA lactylation, ultimately enhancing the regulatory function of DDX17 in maintaining the stemness of LCSCs. This investigation highlights the significance of Kla in modulating the stemness of LCSCs and its impact on the progression of HCC. Targeting lactylation in LCSCs may offer a promising therapeutic approach for treating HCC.