Lactate Tags a Tumor Suppressor and Fuels Liver Cancer Growth

Scientists in China have uncovered a striking example of how a tumor’s own metabolic waste can sabotage one of the body’s natural defenses against cancer. In a study published in the Journal of Translational Medicine, a team led by Zhu Zhang, Zhanfei Chen and Jinqiao Wu, with corresponding author Nanhong Tang of Fujian Medical University Union Hospital, reports that a chemical modification driven by lactate accumulation disables a tumor-suppressive protein called OVOL2, thereby accelerating the growth of hepatocellular carcinoma, the most common form of liver cancer. The work adds a new layer to the growing field of lactylation, a post-translational modification in which lactate-derived molecules are attached to proteins, altering their behavior in ways that can reshape the fate of a cell.

Lactylation first attracted wide attention as a modification of histones, the proteins around which DNA is wound, where it was shown to activate gene expression in response to metabolic cues. More recently, researchers have realized that lactylation also strikes non-histone proteins, potentially rewiring signaling pathways throughout the cell. The new study addresses a key gap in this emerging field: what lactylation actually does to non-histone proteins inside hepatocellular carcinoma, and whether those effects matter for patients. The answer, according to the team, is that lactylation can functionally reprogram a tumor suppressor, converting a molecular brake on cancer into a bystander that no longer applies the brakes effectively.

OVOL2, short for Ovo-like zinc finger 2, is a transcription factor, a DNA-binding protein that controls the activity of target genes. In the liver, it has been associated with restraining epithelial-mesenchymal transition, the cellular program that allows stationary epithelial cells to become invasive and migratory, a hallmark of cancer progression. The researchers began by mining large public datasets from The Cancer Genome Atlas and the Gene Expression Omnibus, and found that OVOL2 messenger RNA is consistently reduced in hepatocellular carcinoma tissues compared with healthy liver tissue. That observation fit the conventional view of OVOL2 as a gene that cancer cells would prefer to silence.

But when the team examined human hepatocellular carcinoma samples and paired adjacent non-tumorous tissues directly, they noticed something paradoxical. Signals associated with OVOL2 lactylation were elevated in the tumor tissues, and higher levels of these lactylation marks correlated with shorter overall survival and increased postoperative recurrence. Notably, however, in multivariate analysis that accounted for other clinical variables, OVOL2 lactylation was not an independent prognostic factor, an important caveat the authors report transparently. The correlation suggests the modification tracks with aggressive disease, even if it does not stand alone as a predictive marker once standard clinical parameters are considered.

To characterize the modification at the molecular level, the researchers deployed a demanding toolkit: immunoprecipitation to pull OVOL2 out of cell extracts, immunoblotting and immunofluorescence to detect and localize the modified protein, immunohistochemistry to map its distribution in tissue sections, and liquid chromatography coupled with tandem mass spectrometry to pinpoint exactly where on the protein the lactyl group lands. The mass spectrometry identified lysine 3, the third amino acid in the OVOL2 protein, as the site of modification. Lysine residues carry positively charged side chains that often participate in critical molecular interactions, so adding a bulky, chemically distinct lactyl group at such a position can profoundly change how a protein behaves.

The enzyme responsible for installing the mark turned out to be KAT8, a lysine acetyltransferase better known for modifying histones. When the team manipulated KAT8 levels, OVOL2 lactylation rose and fell accordingly, establishing KAT8 as the writer of this particular mark. The functional consequences were dramatic. Lactylation at lysine 3 reduced the ability of OVOL2 to accumulate in the nucleus, the compartment where a transcription factor must reside to do its job. Subcellular fractionation experiments confirmed this shift, and the weakened nuclear presence translated into a loss of transcriptional repression at one of OVOL2’s key target genes, TRIM54, which encodes tripartite motif-containing 54, an E3 ubiquitin ligase that tags other proteins for destruction.

With OVOL2’s grip on TRIM54 loosened, TRIM54 levels climbed, and the consequences cascaded further down the chain. The study shows that elevated TRIM54 promotes K48-linked ubiquitination of RBM47, an RNA-binding protein whose abbreviation stands for RNA-binding motif 47. K48-linked ubiquitin chains are the canonical signal that directs a protein to the proteasome, the cell’s garbage disposal complex, for degradation. In other words, the pathway reads like a molecular relay: lactate accumulation leads to KAT8-mediated lactylation of OVOL2 at lysine 3, which weakens the tumor suppressor’s nuclear function, which lifts repression of TRIM54, which destroys RBM47, and which ultimately facilitates hepatocellular carcinoma growth. Each link in that chain was tested with gain- and loss-of-function assays, reporter assays, chromatin immunoprecipitation and CUT&Tag, a technique called cleavage under targets and tagmentation that maps where a protein binds across the genome.

Perhaps the most clinically provocative part of the study is the therapeutic proof of concept. The researchers designed a cell-penetrating peptide, a short amino acid chain that can cross cellular membranes, aimed at reducing OVOL2 lactylation. When evaluated in cell line-derived xenograft models, in which human cancer cells are implanted into animals, the peptide suppressed tumor growth in vivo. The result suggests that blocking a single lactylation event on a single protein may be enough to restore some tumor-suppressive function, offering a template for drugs that target the lactylation machinery rather than the metabolic pathway as a whole. Cell-penetrating peptides remain an early-stage modality, and the authors are careful to frame this as a potential strategy rather than a ready treatment, but the experiment demonstrates that the pathway is pharmacologically addressable.

The broader significance of the work lies in its reframing of what a tumor suppressor is. Textbook descriptions often treat these proteins as fixed entities whose loss, through mutation or deletion, removes a brake on cell division. This study instead highlights what the authors call post-translational modification-dependent functional plasticity: a tumor suppressor can be present and genetically intact yet functionally neutralized by a chemical tag imposed by the metabolic environment. In tumors such as hepatocellular carcinoma, which arise frequently in the context of metabolic disease and hypoxic, nutrient-stressed tissue, lactate is abundant, and the lactylation landscape is correspondingly rich. A suppressor like OVOL2 can thus be silenced without ever touching its gene.

For patients with hepatocellular carcinoma, one of the deadliest cancers worldwide and one whose incidence continues to climb in parallel with obesity, diabetes and viral hepatitis, the study offers both a mechanistic insight and a cautious note of realism. The clinical data link OVOL2 lactylation to survival and recurrence, but not independently of established prognostic factors, and the therapeutic peptide has so far been tested only in animal models. Still, the identification of a KAT8-OVOL2-TRIM54-RBM47 axis gives researchers a defined set of molecular targets, and it strengthens the case that the metabolic tumor microenvironment communicates with the genome not only through gene expression but through chemical edits to the proteins that read the genome itself. As lactylation research matures, tumors may increasingly be understood as ecosystems in which waste products become weapons, and the next generation of therapies may aim to disarm them at the point of attachment.

Subject of Research: Lactylation of the tumor suppressor OVOL2 in hepatocellular carcinoma progression

Article Title: Lactylation of OVOL2 impairs its tumor-suppressive activity to promote hepatocellular carcinoma growth

Article References: Zhang, Z., Chen, Z., Wu, J., Ye, D., Yao, Y., Wu, H., Zhang, X., Yang, H., Wang, X., & Tang, N. (2026). Lactylation of OVOL2 impairs its tumor-suppressive activity to promote hepatocellular carcinoma growth. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-08959-5

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08959-5

Keywords: OVOL2, lactylation, hepatocellular carcinoma, KAT8, TRIM54, RBM47, post-translational modification, tumor suppressor, cancer metabolism, ubiquitination, liver cancer, cell-penetrating peptide