Profiling of Lysine Lactylation Reveals Its Proliferation-promoting Functions in Colorectal Cancer Cells

Tumor cells generate energy through glycolysis and produce lactate as a byproduct. The lactate can be used as a substrate for lysine lactylation (Kla), a post-translational modification that may contribute to cell survival and growth in certain tumors. The colorectal cancer cell line SW480 was identified to have lactylated proteins, however, the role and mechanism of lactylation in colorectal cancer (CRC) are still not well known.

The lactylation modification in HCT116 cells was analyzed by mass spectrometry, followed by bioinformatics analysis. Treatment of 2-DG, oxamate, or siLDH was performed to study the regulatory roles of lactylation in proliferation measured by CCK-8 assays and colony formation assays. Lactylation levels were assessed via Western blotting, immunofluorescence staining, and co-immunoprecipitation followed by Western blotting.

CRC patients had higher levels of Kla in tumor tissues than those in adjacent tissues. Patients with higher levels of Kla had a shorter survival time. We found that Kla was higher in CRC cell line HCT116 and identified 1,295 sites from 699 lactylated proteins in HCT116 cells. These lactylated proteins in CRC cells are enriched in processes such as histone modification and cell proliferation. The inhibition of protein lactylation can suppress the proliferation of CRC cells.

Our characterization of Kla demonstrated the importance of protein lactylation in CRC, thereby providing an important foundation for future elucidation of the pathogenesis of CRC and for the development of treatments to improve the survival time of CRC patients.