Role of lactylation in tumorigenesis: Analysis based on the ten hallmarks of cancer

Abstract

Lactylation, a recently discovered post-translational modification, is crucial in cancer biology, linking cellular metabolism to the regulation of gene expression. This modification involves the attachment of a lactyl group to lysine residues, which affects protein function and plays a key role in cancer progression by influencing major hallmarks of the disease. These hallmarks include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, promoting invasion and metastasis, reprogramming metabolism, avoiding immune destruction, enhancing genomic instability, and fueling tumor-promoting inflammation. Lactylation modifies key signaling pathways, including phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin and nuclear factor kappa-light-chain-enhancer of activated B cells, which are vital for tumor cell survival, growth, and metabolic adaptation. Furthermore, lactylation affects immune evasion and genomic instability, increasing the adaptability and metastatic potential of cancer cells. This review highlights the growing importance of lactylation in regulating cancer hallmarks and its potential as a biomarker for early cancer diagnosis and prognosis. Additionally, enzymes involved in lactylation, such as lactate dehydrogenase and acyltransferases, present promising therapeutic targets. Inhibiting these enzymes may decrease lactylation, inhibit tumor growth, and improve the effectiveness of immunotherapy. A deeper understanding of lactylation’s molecular mechanisms opens new avenues for developing more personalized and effective treatments, underscoring its role as a crucial factor in precision oncology.

Key Words: Lactylation; Tumor microenvironment; Metabolic reprogramming; Immune evasion; Signal transduction

Core Tip: Lactylation links metabolism to gene expression in cancer, serving as a critical epigenetic regulatory mechanism. Lactylation regulates key cancer hallmarks, including uncontrolled growth and invasive metastasis. Targeting lactylation-related enzymes can effectively enhance and improve current cancer therapies. Lactylation markers may serve as reliable cancer biomarkers for early diagnosis and prognosis. Understanding lactylation can lead to personalized cancer treatments.

INTRODUCTION

In cancer biology, the regulation of protein function via post-translational modifications (PTMs) is critical in driving the hallmarks of cancer - traits that enable tumor cells to sustain growth, evade growth suppression, resist cell death, and promote invasiveness, among others. One such modification, lactylation - a newly identified PTM in which a lactyl group is covalently attached to lysine residues - has emerged as a key factor connecting cellular metabolism with gene expression regulation[1]. This modification introduces a distinct chemical structure, unlike other well-known PTMs like acetylation and methylation, and has been shown to dynamically modify protein function, driving cancer progression[2].

Lactylation is closely linked to the core biological processes that define cancer, particularly by affecting key proteins involved in sustaining tumor growth and survival. It plays a central role in many of the ten hallmark characteristics of cancer, such as sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, activating invasion and metastasis, reprogramming energy metabolism, and evading immune surveillance[3]. Lactylation impacts several critical signaling pathways, including phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor kappa B (NF-κB), both of which are essential for tumor cell survival and growth. By modulating these pathways, lactylation aids cancer cells in adapting to their challenging metabolic environments, driving their aggressive and unchecked growth[4].

Furthermore, lactylation plays a key role in linking metabolic processes with epigenetic regulation. By modifying proteins like histones, transcription factors, and metabolic enzymes, lactylation directly influences gene expression and cellular function[5]. This modification highlights how tumors use metabolic byproducts like lactate - not just as an energy source, but also as a signaling molecule that drives tumorigenesis. Lactylation introduces a novel mechanism linking metabolic changes in the tumor microenvironment with the regulation of cancer-related genes, creating a self-reinforcing loop that accelerates cancer progression[6].

Understanding the role of lactylation in these key processes opens new avenues for targeted cancer therapy. Focusing on the regulation of lactylation and its impact on cancer hallmarks may lead to new therapeutic strategies that target this modification to disrupt the molecular networks supporting tumor growth, survival, and metastasis[7]. As a bridge between metabolism, epigenetics, and cancer biology, lactylation holds significant potential for the development of novel precision cancer therapies, offering deeper insights into how metabolic changes drive tumor transformation and persistence[8].

OVERVIEW OF LACTYLATION MODIFICATION

Definition and mechanism of lactylation

Lactylation is a novel PTM characterized by the covalent attachment of a lactate molecule to lysine residues on proteins. Similar to classical epigenetic modifications such as acetylation and methylation, lactylation features a unique chemical structure that imparts distinct functional properties to proteins[3]. Lactylation not only regulates protein structure and function but also plays a crucial role in gene expression, cellular metabolism, and signal transduction. With the advancement of mass spectrometry technology, the discovery of lactylation has provided new insights into the interaction between metabolism and epigenetics, particularly in cancer biology, where it shows significant potential for future research[9].

The mechanism of lactylation primarily involves the transfer of lactate as an acyl group. First, lactate is activated within the cell, typically by forming the activated lactyl-CoA intermediate, a process similar to acyl activation in other acyl transfer reactions[10]. Next, specific acyltransferases catalyze the transfer of the lactyl group from its activated form to lysine residues on target proteins, forming a lysine-lactyl ester bond. The enzymes that specifically catalyze lactylation are not yet fully identified, but studies suggest that certain known acyltransferases, such as histone acetyltransferases (HATs), may have the ability to catalyze lactylation[11]. Furthermore, the reverse modification of lactylation may be mediated by specific delactylases. Preliminary evidence indicates that certain members of the histone deacetylase (HDAC) family may possess delactylation activity. Lactylation has multiple effects on protein structure and function, including introducing additional hydrophobicity and steric hindrance, which may lead to conformational changes, affecting protein stability and interactions with other molecules. The reversibility of this modification allows cells to dynamically regulate protein lactylation, adapting to environmental changes and signaling requirements[12] (Figure 1).

Figure 1 Lactylation in the tumor microenvironment is influenced by elevated lactate concentrations, resulting from high sugar fermentation, low oxygen levels, and inflammatory responses. This metabolic environment affects key enzymes such as the lactate dehydrogenase complex, adenosine triphosphate/adenosine diphosphate, and nicotinamide adenine dinucleotide (oxidized form)/nicotinamide adenine dinucleotide (reduced form), which regulate the lactylation of substrate proteins. Acyltransferase complexes, including p300/CBP, catalyze the lactylation of both histone proteins and non-histone proteins, such as transcription factors and metabolic enzymes. These modifications contribute to tumor cell survival, immune regulation, and energy induction through proteins like sirtuin 1/2, histone deacetylase 3, and general control nonderepressible 5. ATP: Adenosine triphosphate; ADP: Adenosine diphosphate; NAD⁺: Nicotinamide adenine dinucleotide (oxidized form); NADH: Nicotinamide adenine dinucleotide (reduced form); SIRT: Sirtuin; HDAC3: Histone deacetylase 3; GCN5: General control nonderepressible 5; H3K23: Histone H3 lysine 23; H3K14: Histone H3 lysine 14.

Regulatory enzymes of lactylation

The dynamic regulation of lactylation depends on specific enzymes, including acyltransferases that catalyze the transfer of lactate molecules to lysine residues on proteins, and delactylases that remove the lactyl modification and restore the protein to its original state. The activity, specificity, and expression patterns of these enzymes across different cell types are crucial for regulating the lactylation modification[13].

Acyltransferases are key enzymes that catalyze the transfer of lactate molecules to lysine residues on proteins, with members of the HAT family being the primary contributors. Specifically, p300/CBP-associated factor (p300/CBP) is considered one of the important enzymes catalyzing lactylation[14]. p300/CBP plays a key role in acetylation reactions, but it also exhibits acyltransferase activity for lactate, adding lactyl groups to both histone and non-histone lysine residues. The expression levels and activity of p300/CBP vary significantly across different cell types. For example, in tumor cells, p300/CBP is often upregulated to meet the high metabolic demands and rapid proliferation, thereby promoting lactylation[15]. Additionally, in immune cells such as macrophages and T cells, p300/CBP activity is regulated by the cell’s metabolic state and microenvironmental signals, influencing the role of lactylation in gene expression and cellular function. In addition to p300/CBP, general control nonderepressible 5 is another important member of the HAT family with potential to catalyze lactylation. General control nonderepressible 5 expression in specific cell types, such as neurons and stem cells, suggests its role in mediating the interaction between metabolism and epigenetics in the development and functional regulation of these cells via lactylation[16]. The activity of acyltransferases depends not only on their expression levels but also on various regulatory factors, including intracellular lactate concentration, coenzyme A availability, and other metabolic signaling molecules. For example, elevated lactate levels can enhance the catalytic activity of p300/CBP, promoting more lactylation and establishing a feedback loop between metabolism and epigenetics[17] (Figure 1).

Delactylases are responsible for removing lactyl modifications from lysine residues on proteins, restoring the protein to its original state. Currently, members of the HDAC family, particularly silent information regulator sirtuin 1 (SIRT1) and SIRT2, are considered the main delactylases. These enzymes not only catalyze the removal of acetyl groups but also exhibit the ability to remove lactyl groups[18]. SIRT1 is widely expressed in various cell types, including hepatocytes, adipocytes, and immune cells. Through delactylation, SIRT1 regulates the function of both histones and non-histone proteins, influencing gene expression, cellular metabolism, and stress responses. For example, in tumor cells, the activity of SIRT1 can reverse the effects of lactylation on gene expression, inhibiting tumor growth and progression. SIRT2 is primarily expressed in neuronal and muscle cells, where its delactylation activity plays an important role in regulating the cell cycle, metabolic balance, and stress responses. Studies show that SIRT2 removes lactyl modifications from histones and metabolic enzymes, participating in the regulation of cellular energy metabolism and the response to metabolic stress[19]. In addition to the SIRT family, HDAC3 also demonstrates delactylation activity, especially in immune cells, where it modulates lactylation to affect the expression of inflammatory genes and immune cell function. For instance, HDAC3 delactylates transcription factors such as NF-κB, inhibiting inflammatory responses and regulating immune cell activity and differentiation. The activity of delactylases is also regulated by various factors, including the intracellular energy state, redox status, and other signaling molecules. High adenosine triphosphate levels and a low nicotinamide adenine dinucleotide (oxidized form)/nicotinamide adenine dinucleotide (reduced form) ratio enhance the delactylation activity of SIRT family enzymes, promoting the reversal of lactylation. Additionally, the activation of cellular stress and signaling pathways can regulate the expression and activity of delactylases, further influencing the dynamic balance of lactylation modifications[20] (Figure 1).

ANALYSIS OF THE RELATIONSHIP BETWEEN LACTYLATION AND THE TEN HALLMARKS OF CANCER

Sustaining proliferative signaling

Lactylation, as a novel epigenetic modification, plays a critical role in regulating the sustained proliferative signaling in cancer cells. For instance, emerging evidence suggests that key receptor tyrosine kinases involved in proliferation, such as the epidermal growth factor receptor (EGFR), may be targets of lactylation[21]. EGFR is a key receptor tyrosine kinase involved in signaling pathways that regulate cell proliferation, differentiation, and survival. In cancer cells, EGFR is often aberrantly activated through overexpression, genetic mutations, or other mechanisms, driving sustained cell proliferation. While proteome-wide screens are still needed to identify specific sites, the modification of lysine residues within the kinase domain could potentially alter EGFR’s conformation and enhance its tyrosine kinase activity. This, in turn, would promote the continuous activation of downstream pathways like PI3K/AKT, ultimately facilitating cell proliferation and survival. EGFR is a key receptor tyrosine kinase whose signaling is central to cell proliferation, differentiation, and survival, and its aberrant activation is a common driver of cancer. The potential for lactylation to directly modulate its function represents an important area of investigation, linking metabolic state directly to one of the most critical oncogenic signaling nodes[21-23] (Figure 2).

Figure 2 Lactylation, as a post-translational modification, affects multiple cellular processes by modifying lysine residues on target proteins. This modification enhances cell signaling pathways, such as the nuclear factor kappa-light-chain-enhancer of activated B cells and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin pathways, promoting cell proliferation and inhibiting apoptosis. It also regulates the cell cycle by modifying key proteins involved in cycle progression. In addition to signaling, lactylation alters chromatin structure, making it more open, and enhances gene expression by activating transcription factors and related genes. The modification also influences protein stability by extending the half-life of proteins, enhances enzyme activity, and induces conformational changes that adjust protein functions. Furthermore, lactylation plays a critical role in metabolic reprogramming and overall protein function enhancement, thereby contributing to tumor progression and immune escape. MMP9: Matrix metallopeptidase 9; LDH: Lactate dehydrogenase; STAT6: Signal transducer and activator of transcription 6; PPAR: Peroxisome proliferator-activated receptor; Arg1: Arginase 1; Mrc1: Mannose receptor C-type 1; TAM: Tumor-associated macrophage; NF-κB: Nuclear factor kappa B; AP-1: Activator protein 1; MMPS: Matrix metallopeptidases; IL: Interleukin; TGF: Transforming growth factor; NK: Natural killer.

Lactylation of EGFR promotes the sustained activation of the PI3K/AKT signaling pathway, further driving cancer cell proliferation and survival. The PI3K/AKT pathway is a critical intracellular signaling cascade involved in various biological processes, including cell proliferation, metabolic reprogramming, and apoptosis inhibition. After lactylation, EGFR’s activated state is sustained, continually recruiting and activating PI3K, which subsequently phosphorylates and activates AKT[24]. This sustained AKT activation promotes the expression of cell cycle proteins, enhancing the progression of the cell cycle, while also inhibiting the expression and activity of pro-apoptotic proteins, allowing cancer cells to evade immune surveillance and programmed cell death. Furthermore, sustained AKT activation promotes mammalian target of rapamycin (mTOR) signaling activity, further supporting protein synthesis and cell growth in cancer cells (Figure 2). This cascade of signaling enhances the proliferative and anti-apoptotic capacities of cancer cells, driving the continued progression of the tumor[25].

In addition to EGFR, lactylation can modify other key proliferation-related proteins, further enhancing sustained proliferative signaling. For example, lactylated myelocytomatosis oncogene (MYC) transcription factor exhibits increased stability and transcriptional activity in cancer cells, promoting the expression of genes related to cell proliferation and metabolism. Lactylation of MYC enhances its DNA binding ability, increasing its transcriptional activation of target genes, thus driving cell cycle progression and metabolic reprogramming[3]. Additionally, lactylation can modify the cell cycle regulator cyclin D1, enhancing its binding affinity for clinical evidence on CDK4/6, which facilitates the transition from G1 to S phase, accelerating cell proliferation. The lactylation modifications of these proteins work synergistically to form a robust proliferative signaling network, supporting continuous cancer cell proliferation and rapid tumor growth[3].

Lactylation not only directly impacts proliferative signaling pathways but is also closely linked to tumor metabolic reprogramming. Cancer cells produce large amounts of lactate through efficient glycolysis, and the accumulation of lactate is not only used as a metabolic byproduct but also enhances the transmission of proliferative signals via lactylation[3]. This bidirectional regulatory mechanism between metabolism and epigenetics creates a self-reinforcing loop that further drives the continuous proliferation and adaptive evolution of cancer cells. For example, high lactate concentrations promote the lactylation of EGFR, enhancing the activity of the PI3K/AKT pathway, while activation of this pathway further stimulates glycolysis, increasing lactate production and creating a positive feedback loop (Figure 2). This synergistic effect not only supports the energy needs of cancer cells but also enhances their survival and proliferative capacity in a harsh microenvironment[26].

Evading growth suppressors

Lactylation modifies key growth suppressors such as p53 and Rb proteins (retinoblastoma protein), reducing their functional activity, which in turn promotes cell cycle progression and the continuous proliferation of cancer cells. p53 is a crucial tumor suppressor protein that plays a broad role in cell cycle regulation, DNA repair, and apoptosis induction. In normal cells, p53 monitors DNA damage and other cellular stress signals to regulate cell cycle arrest or induce apoptosis, preventing the proliferation of damaged cells[27]. However, in cancer cells, p53 is often inactivated through mutations or other mechanisms, weakening its tumor suppressor function. Studies have shown that lactylation modifies p53’s lysine residues, significantly reducing its DNA binding ability and transcriptional activity. The specific mechanisms are as follows: (1) Reduced DNA binding ability: Lactylation of p53’s lysine residues alters its structural conformation, lowering its affinity for DNA. This structural change impairs p53’s ability to bind to its target gene promoter regions, inhibiting its transcriptional activation of target genes; (2) Inhibition of transcriptional activity: Lactylation not only affects p53’s DNA binding but also interferes with its interaction with coactivators (such as CBP/p300), further suppressing its transcriptional activity. As a result, p53 cannot effectively activate the expression of genes involved in cell cycle arrest and apoptosis, facilitating continuous cell cycle progression and cancer cell proliferation; and (3) Promotion of cell cycle progression: Because p53’s function is suppressed by lactylation, cancer cells can bypass the G1/S checkpoint, continuously advancing the cell cycle and promoting rapid cell proliferation. This process contributes to rapid tumor growth and malignant progression[28].

Rb protein is another key growth suppressor that inhibits the transition from G1 to S phase of the cell cycle by binding to the E2F transcription factor. In normal cells, Rb protein prevents cells from entering S phase before they are ready to replicate DNA by inhibiting E2F activity. However, in cancer cells, Rb protein is often inactivated by phosphorylation, mutations, or other mechanisms, relieving its suppression on E2F and promoting continuous cell cycle progression[29]. Lactylation plays a crucial role in this process: (1) Impact on Rb protein’s binding ability to E2F: Lactylation of Rb’s lysine residues alters its structural conformation, reducing its affinity for E2F transcription factor. This modification weakens Rb’s inhibitory effect on E2F, allowing E2F to freely activate the expression of genes related to cell cycle progression; (2) Promotion of cell cycle progression: As Rb can no longer effectively inhibit E2F, E2F continuously activates cyclins and other related genes, facilitating the transition from G1 to S phase and driving the ongoing cell cycle. This process not only enhances cancer cell proliferation but also helps them adapt to the demands of rapid growth and metabolic reprogramming; and (3) Interaction with other signaling pathways: Lactylated Rb protein may also further enhance cell cycle progression through interactions with other signaling pathways. For instance, lactylation may influence the interaction between Rb protein and the PI3K/AKT pathway, synergistically promoting cell proliferation and survival[30] (Figure 2).

In addition to p53 and Rb proteins, lactylation may also modify other growth suppressors, further enhancing the ability of cancer cells to evade growth inhibition. For example, lactylation of phosphatase and tensin homolog can reduce its phosphatase activity, weakening its inhibition of the PI3K/AKT pathway, thus promoting cell proliferation and survival. Furthermore, lactylation may affect the stability and function of other cell cycle inhibitors, such as p21 and p27, further facilitating the continuous progression of the cell cycle.

Resisting cell death

In reported model systems, lactylation has been reported to contribute to the resistance of cell death by modulating the expression of key anti-apoptotic proteins, most notably B-cell lymphoma 2 protein (Bcl-2). While direct lactylation of the Bcl-2 protein has not been established, a novel post-transcriptional mechanism has recently been uncovered. In renal cell carcinoma, the lactylation of the m6A RNA-binding protein YTHDC1 has been shown to promote its phase-separation capabilities, leading to enhanced stability of its target mRNAs, including Bcl-2 mRNA. By increasing the half-life of the Bcl-2 transcript, this indirect lactylation-driven mechanism leads to elevated Bcl-2 levels, thereby shifting the cellular balance towards survival and inhibiting apoptosis. This highlights a sophisticated layer of regulation where lactylation impacts gene expression not only at the transcriptional level but also post-transcriptionally to fortify the anti-apoptotic defenses of cancer cells[8,31,32] (Figure 2).

Lactylation can indirectly influence a cell’s ability to undergo apoptosis by regulating the function of cell cycle proteins. Cyclin D1 is a key protein in cell cycle regulation, facilitating the transition from the G1 phase to the S phase. Lactylation of cyclin D1 enhances its binding affinity for clinical evidence on CDK4/6, accelerating cell cycle progression and promoting cell proliferation. Additionally, lactylated cyclin D1 reduces sensitivity to apoptotic signals, helping cancer cells avoid apoptosis while rapidly proliferating (Figure 2). This dual regulatory mechanism further enhances the survival and proliferative potential of cancer cells[3].

Anti-apoptotic functions have been suggested to be reinforced by lactylation through modulation of several signaling pathways, including the PI3K/AKT and NF-κB pathways. Continuous activation of the PI3K/AKT pathway inhibits the activity of FoxO transcription factors, reduces the expression of pro-apoptotic genes, and increases the expression and function of Bcl-2. Moreover, activation of the NF-κB pathway also promotes the expression of anti-apoptotic genes, enhancing the resistance of cancer cells to apoptotic signals (Figure 2). Lactylation modifies these pathways to increase their activity, thereby strengthening the anti-apoptotic capacity of cancer cells, enabling them to survive and proliferate in unfavorable microenvironments[33].

Enabling replicative immortality

In several cancer models, lactylation has been linked to increased telomerase expression and activity, extending telomere length and supporting the unlimited replication potential of cancer cells. Telomerase is a reverse transcriptase enzyme responsible for adding repeated DNA sequences to the ends of telomeres, thus maintaining their length. In most normal cells, telomerase activity is low, leading to gradual telomere shortening, which limits the number of cell divisions. However, in cancer cells, telomerase is typically highly activated, supporting their capacity for unlimited replication[7]. Studies have shown that lactylation can modify key lysine residues (e.g., K620) on telomerase, significantly enhancing its reverse transcriptase activity. Lactylation alters the conformation of telomerase, increasing its binding affinity for telomeric DNA and promoting the telomere elongation process. Moreover, lactylation has been associated with enhanced interactions between telomerase and its cofactors, potentially improving catalytic efficiency and stability[3].

Lactylation not only directly influences the activity of telomerase but also indirectly modulates its activity by regulating the expression of telomerase genes, such as telomerase reverse transcriptase. Through effects on transcription factors such as MYC, lactylation has been proposed to increase their stability and transcriptional activity, thereby promoting telomerase reverse transcriptase transcription and elevating telomerase expression. In this way, lactylation supports the sustained high expression of telomerase in cancer cells, ensuring stable maintenance of telomere length and the cell’s capacity for unlimited replication[26].

Reported findings further suggest that lactylation may coordinate telomerase activity with cell-cycle regulators such as cyclin D1, facilitating the transition from G1 to S phase and sustaining continuous cell proliferation. The sustained activity of telomerase ensures the restoration of telomere length after each cell division, preventing cells from entering senescence or apoptosis due to telomere shortening. Additionally, lactylated cell cycle proteins promote cell cycle progression, further enhancing the proliferative potential of the cell[13].

Elevated lactate levels in the tumor microenvironment not only directly promote lactylation modifications but also optimize the metabolic network of cancer cells through interactions with other metabolic byproducts. For example, high lactate concentrations promote the lactylation modification and expression of telomerase, enhancing its activity and stability. Telomerase activation then supports rapid cell division, further increasing lactate production and accumulation, thereby establishing a positive feedback loop. This synergistic effect not only supports the energy requirements of cancer cells but also enhances their survival and proliferative capacity in harsh microenvironments[34].

Inducing angiogenesis

Lactate promotes angiogenesis through a dual-action mechanism centered on hypoxia-inducible factor 1α (HIF-1α). First, as a metabolic byproduct, lactate can inhibit prolyl hydroxylase activity, which prevents the degradation of HIF-1α and leads to its stabilization even under normoxic conditions. Second, and more directly, HIF-1α itself is a substrate for lactylation. This PTM has been shown to significantly enhance its transcriptional activity. Studies using chromatin immunoprecipitation have demonstrated that lactylated HIF-1α exhibits increased promoter occupancy at hypoxia-responsive genes, including vascular endothelial growth factor (VEGF). This lactylation-driven enhancement of transcriptional output, coupled with lactate-mediated protein stabilization, creates a powerful synergistic loop that robustly drives the expression of VEGF and other pro-angiogenic factors, thereby inducing angiogenesis to support tumor growth[35,36].

VEGF is a key factor in angiogenesis, responsible for promoting the proliferation, migration, and lumen formation of new endothelial cells. Lactylation of HIF-1α significantly enhances its transcriptional activation of the VEGF gene, promoting its efficient expression. High levels of VEGF secretion not only stimulate the formation of new blood vessels but also enhance the function of endothelial cells through autocrine and paracrine mechanisms, promoting angiogenesis and vessel stability[37]. Additionally, elevated VEGF expression increases vascular permeability, facilitating the invasion and metastasis of tumor cells. Meanwhile, high lactate concentrations promote the lactylation of HIF-1α, enhancing its transcriptional activity, which further stimulates VEGF expression and angiogenesis to meet the increased metabolic demands of lactate production. This bidirectional regulatory mechanism between metabolism and epigenetics supports the ongoing angiogenesis in tumors, promoting rapid tumor growth and metastasis[38].

Lactylation not only promotes VEGF expression but also directly affects the function of endothelial cells. Lactylated signaling molecules, such as VEGF receptor 2, enhance their activity, promoting the migration and proliferation of endothelial cells. Additionally, lactylation regulates the matrix degradation capacity of endothelial cells, facilitating the formation and expansion of new blood vessels. These effects collectively promote angiogenesis, meeting the metabolic demands of rapid tumor proliferation[39].

Activating invasion and metastasis

Lactylation modifies epithelial-to-mesenchymal transition (EMT) transcription factors (e.g., Snail, Slug) and matrix metalloproteinases (MMPs), enhancing their stability and function, promoting cell migration and matrix degradation, and thereby driving cancer cell invasion and metastasis[40]. EMT is a crucial process through which cancer cells acquire invasive and migratory abilities, involving the transformation of epithelial cells into mesenchymal cells, thereby enhancing cell motility and invasiveness. Studies have shown that lactylation can modify key EMT transcription factors, such as Snail and Slug, significantly enhancing their stability and transcriptional activity[41]. Lactylation modifies the conformation of these transcription factors, increasing their binding affinity for DNA and other coactivators, thus promoting the expression of EMT-related genes, such as vimentin and N-cadherin. Furthermore, lactylated Snail and Slug are more effective in suppressing the expression of epithelial markers, such as E-cadherin, further driving the mesenchymal transition and the formation of an invasive phenotype[9].

MMPs are enzymatic proteins responsible for degrading the extracellular matrix, facilitating cancer cell invasion and migration. Lactylation modifies the lysine residues of MMPs, significantly enhancing their matrix-degrading activity. Specifically, lactylation alters the conformation of MMPs and the accessibility of their enzymatic active sites, enhancing their binding and degradation of matrix proteins. Additionally, lactylated MMPs are more stable in the tumor microenvironment, with an extended half-life, ensuring sustained matrix degradation activity. This modification mechanism not only enhances the invasive capability of cancer cells but also supports their colonization and metastasis in distant organs[42].

Lactylation also enhances the migratory capacity of cancer cells by regulating the function of cell migration and adhesion molecules. Lactylated integrins and adhesion molecules (e.g., Cadherins) alter their interactions with the extracellular matrix and other cells, promoting cell motility and invasiveness[10]. For example, lactylated integrins strengthen their binding to matrix proteins, facilitating cell adhesion and migration. Additionally, lactylated adhesion molecules regulate dynamic interactions between cells and the matrix, promoting cell movement and invasion. These regulatory mechanisms enable cancer cells to more effectively invade surrounding tissues and metastasize to distant organs via the bloodstream or lymphatic system[43].

Multiple studies indicate that lactylation may facilitate cancer cell invasion and metastasis through the engagement of signaling pathways such as PI3K/AKT and mitogen-activated protein kinases. Persistent activation of the PI3K/AKT pathway promotes cell proliferation and survival while also enhancing cell migration and invasion. Activation of the mitogen-activated protein kinases pathway regulates cell motility and morphological changes, supporting the invasive phenotype of the cells[44] (Figure 2). Lactylation modifies these signaling pathways to increase their activity, thereby enhancing the invasion and metastasis capabilities of cancer cells, allowing for more efficient spreading and metastatic colonization in the body[45].

High lactate levels in the tumor microenvironment not only directly promote lactylation modifications but also enhance cancer cell invasion and metastasis through interactions with other molecules. For example, elevated lactate concentrations promote the lactylation of EMT transcription factors and MMPs, enhancing their function and stability, thereby driving cell invasion and migration[46]. Additionally, lactylation regulates the function of immune and stromal cells, creating a favorable microenvironment that supports tumor invasion and metastasis. This bidirectional regulatory mechanism between metabolism and epigenetics supports the invasion and metastasis of cancer cells, driving tumor progression and malignant transformation[10].

Reprogramming energy metabolism

Enhanced catalytic activity of key metabolic enzymes, including hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2), has been attributed to lactylation, thereby promoting glycolysis and accelerating glucose metabolism to generate lactate and support the metabolic demands of rapidly proliferating cancer cells. HK2 is a key enzyme in the glycolytic pathway, catalyzing the conversion of glucose to glucose-6-phosphate, thus initiating glycolysis[47]. In cancer cells, the elevated expression and activity of HK2 are critical for efficient glycolysis and rapid proliferation. Studies have shown that lactylation modifies the lysine residue of HK2 (e.g., K62), significantly enhancing its catalytic activity. Lactylation modifies the conformation of HK2, increasing its binding affinity for glucose and catalytic efficiency, thus promoting rapid glucose metabolism. Additionally, lactylation enhances the binding of HK2 to mitochondria on the cell membrane, optimizing energy production efficiency to meet the high energy demands and rapid division of the cell[48].

PKM2 is another key enzyme in the glycolytic pathway, catalyzing the conversion of phosphoenolpyruvate to pyruvate. In cancer cells, PKM2 often exists in an inactive dimer form, supporting continuous glycolysis and metabolic reprogramming. Lactylation modifies the lysine residue of PKM2 (e.g., K305), promoting its conversion to the active tetramer form and enhancing its catalytic activity[49]. Lactylation alters the conformation of PKM2, facilitating its binding to cofactors and substrates, which increases enzyme activity and catalytic efficiency. Additionally, lactylation regulates PKM2’s function in the nucleus, involving gene expression regulation and cell cycle control, further supporting rapid cell proliferation and division[47].

High lactate levels in the tumor microenvironment not only directly promote lactylation modifications but also optimize the metabolic network of cancer cells through interactions with other metabolites. For example, elevated lactate concentrations promote the lactylation of HK2 and PKM2, enhancing the activity of the glycolytic pathway and further increasing lactate production, thereby creating a self-reinforcing metabolic loop.

Evading immune destruction

In tumor-immune contexts examined to date, increased expression and function of programmed cell death ligand 1 (PD-L1) have been linked to lactylation, contributing to suppressed T-cell activity and immune evasion. At the same time, by modifying related proteins, lactylation enhances the formation of an immunosuppressive microenvironment, further supporting cancer cell survival and dissemination. PD-L1 is an immune checkpoint molecule on the surface of cancer cells that binds to the PD-1 receptor on T-cells, inhibiting their activity and helping cancer cells evade immune system attacks. Studies have shown that lactylation can modify the lysine residue of PD-L1 (e.g., K162), significantly enhancing its expression and immunosuppressive function[50]. PD-L1 stability on the cell surface has also been proposed to be enhanced by lactylation, prolonging its persistence and facilitating interaction with the PD-1 receptor. Additionally, lactylation increases the affinity of PD-L1 for its ligand, improving the efficiency of immune suppressive signaling and effectively inhibiting T-cell activity and cytotoxicity[51].

Lactylation not only regulates the function of PD-L1 but also directly affects the activity and function of immune cells. High lactate concentrations promote lactylation modifications, inhibiting the function of T-cells and natural killer (NK) cells, thereby reducing their cytotoxicity against cancer cells. For instance, lactylation-modified nuclear factor of activated T cells transcription factors exhibit lower transcriptional activity in T-cells, inhibiting T-cell proliferation and cytokine secretion[4]. Accumulation of immunosuppressive cells, including regulatory T cells and M2 macrophages, has also been associated with lactylation, further reinforcing immunosuppression within the tumor microenvironment.

Formation of an immunosuppressive tumor microenvironment has likewise been suggested to be promoted by lactylation through multiple mechanisms that support tumor escape and dissemination. Elevated lactate levels can trigger the secretion of immunosuppressive cytokines, such as interleukin (IL)-10 and transforming growth factor-β, which impair the function of effector immune cells[52]. In addition, lactylation-modified transcription factors and signaling molecules enhance the expression of immunosuppressive genes, regulating immune cell differentiation and function to create a microenvironment favorable for cancer cell survival and proliferation. This immunosuppressive microenvironment not only helps cancer cells evade immune surveillance but also supports their continued growth and metastasis within the body[12].

Lactylation regulates several immune-related signaling pathways, enhancing immunosuppressive functions. For example, lactylation-modified NF-κB transcription factors promote the expression of immunosuppressive genes, amplifying inflammatory and immune-suppressive responses. In addition, lactylation can modulate signaling pathways such as Janus kinase-signal transducer/activator of transcription (STAT) and PI3K/AKT, influencing immune cell activity and differentiation (Figure 2). These regulatory mechanisms of signaling pathways collectively enhance the ability of cancer cells to evade immune surveillance, supporting their continued survival and spread[53].

Genome instability and mutation

Lactylation modifies DNA repair proteins [such as breast cancer gene 1 (BRCA1)] and other genome maintenance factors, impairing their repair functions, increasing genomic instability, and promoting the accumulation of mutations. BRCA1 is a critical DNA repair protein involved in the homologous recombination repair pathway, repairing double-strand breaks. In cancer cells, lactylation can modify the lysine residues of BRCA1 (e.g., K170), significantly reducing its DNA-binding capacity and repair function[54]. Lactylation alters the conformation of BRCA1, reducing its interaction with DNA and other repair factors, thereby inhibiting the efficiency of homologous recombination repair. This modification mechanism prevents cancer cells from efficiently repairing DNA damage, increasing genomic instability and mutation frequency[21].

In addition to BRCA1, lactylation can also modify other key genome maintenance factors, such as ataxia-telangiectasia mutated and ataxia-telangiectasia mutated and Rad3-related proteins. These proteins play crucial roles in the DNA damage response and repair processes. Lactylation modifies these proteins to reduce their activity and function, inhibiting DNA damage signaling and repair mechanisms, which further increases genomic instability and mutation accumulation[55].

Lactylation also regulates chromatin structure, affecting genomic stability and mutation frequency. For instance, lactylation of histones H3 and H4 alters chromatin’s open state, increasing DNA accessibility and promoting the accumulation of errors during DNA replication and transcription. Additionally, lactylation can modulate the function of chromatin remodeling complexes, affecting chromatin dynamics and gene expression, thereby increasing genomic instability[32].

Lactylation regulates cyclins and cell cycle checkpoints, influencing genomic stability during cell division. For example, lactylation-modified cyclin E1 promotes the transition from G1 to S phase, increasing the rate and complexity of DNA replication, which raises the likelihood of DNA damage and mutations. Additionally, lactylation can inhibit the function of cell cycle checkpoint proteins, such as checkpoint kinase 1 and checkpoint kinase 2, reducing the response to DNA damage and repair, thereby further promoting genomic instability[56].

Lactylation regulates multiple signaling pathways, such as PI3K/AKT and NF-κB, influencing genomic stability and mutation accumulation. Persistent activation of the PI3K/AKT pathway suppresses cell cycle checkpoints and DNA repair mechanisms, increasing genomic instability. Activation of the NF-κB pathway promotes genomic instability and mutation accumulation by regulating inflammation and cellular stress responses. Activation of these signaling pathways has been proposed to be enhanced by lactylation, which may consequently increase genomic instability and mutation frequency[33] (Figure 2).

Tumor-promoting inflammation

Lactylation modifies the NF-κB transcription factor, enhancing its activity and promoting the secretion of inflammatory factors, thereby strengthening the inflammatory microenvironment and supporting tumor growth and progression. NF-κB is a critical transcription factor involved in regulating inflammation, cell survival, and immune responses. In the tumor microenvironment, persistent activation of NF-κB promotes the expression of inflammation-related genes [e.g., IL-6, tumor necrosis factor (TNF-α)], amplifying the inflammatory response and supporting tumor growth and invasion[57]. Studies show that lactylation can modify the lysine residue of NF-κB (e.g., K310), significantly enhancing its transcriptional activity. Lactylation alters the conformation of NF-κB, increasing its ability to bind DNA and coactivators, thus promoting the efficient expression of inflammatory factors. Furthermore, lactylation enhances the stability of NF-κB, prolonging its half-life in the nucleus and ensuring the continuous transmission of inflammatory signals[58].

Lactylation of NF-κB has been proposed to enhance its transcriptional activation of inflammatory mediators, thereby promoting the secretion of cytokines such as IL-6, TNF-α, and IL-1β. These inflammatory factors not only promote tumor cell proliferation and survival but also modulate immune and stromal cells in the tumor microenvironment, creating a favorable environment for tumor growth and invasion. For example, IL-6 promotes tumor cell proliferation and anti-apoptotic capabilities through the Janus kinase-signal transducer/STAT3 signaling pathway, while TNF-α enhances cancer cell invasion and metastasis by regulating the expression of cell adhesion molecules and MMPs[57].

Lactylation regulates signaling pathways to promote the polarization of macrophages toward the pro-tumor M2 phenotype. M2 macrophages have immune-suppressive properties and promote tumor growth by secreting factors that enhance angiogenesis, cell proliferation, and extracellular matrix remodeling. Studies show that lactylation enhances the activity of NF-κB and other transcription factors, promoting the differentiation and functional expression of M2 macrophages, thereby supporting immune suppression and pro-tumor inflammatory responses in the tumor microenvironment[45].

Lactylation regulates multiple signaling pathways, such as the PI3K/AKT and STAT3 pathways, further promoting the formation and maintenance of tumor-promoting inflammation. Persistent activation of the PI3K/AKT pathway enhances NF-κB activity, promoting the expression and secretion of inflammatory factors while suppressing anti-inflammatory factors, thereby creating a positive feedback loop that favors tumor growth and inflammation. Activation of the STAT3 pathway promotes the expression of immunosuppressive cytokines, enhancing the immune-suppressive function of the inflammatory microenvironment and supporting the sustained growth and invasiveness of the tumor[59] (Figure 2).

MOLECULAR MECHANISMS OF LACTYLATION MODIFICATION

Regulation of gene expression

Histone lactylation: In the context of histone lactylation, modifications such as histone 3K18 lactylation (H3K18 La), where a lactyl group is added to the lysine residue at position 18 of histone H3, significantly alter chromatin structure. Specifically, lactylation reduces the positive charge of histone H3, weakening its electrostatic interactions with the negatively charged DNA and other histones, leading to a relaxed nucleosome structure and a more open chromatin state[32]. This structural relaxation increases the accessibility of gene regions, allowing transcription factors and the transcriptional machinery to more easily bind to DNA, thereby enhancing the transcriptional efficiency of target genes. For example, the accumulation of H3K18 La enhances the expression of genes related to cell proliferation and survival, such as c-Myc and cyclin D1, promoting rapid tumor cell proliferation. Additionally, lactylation of other histones, such as H3K14 La and H4K8 La, regulates the expression of different genes through similar mechanisms, contributing to processes like cell cycle regulation and DNA repair. Histone lactylation often cooperates with other histone modifications, such as acetylation and methylation, to jointly regulate chromatin dynamics and ensure precise control over gene expression[60].

Non-histone lactylation: Non-histone lactylation modifications have a profound impact on the function of various transcription factors, RNA-binding proteins, and transcriptional co-factors. For instance, lactylation modifications significantly alter the DNA-binding ability and transcriptional regulatory functions of transcription factors such as HIF-1α and p53. Specifically, HIF-1α is activated under hypoxic conditions and translocates to the nucleus, where it regulates genes associated with metabolic reprogramming and angiogenesis[12]. For HIF-1α, lactylation at lysine residues (e.g., K27 La) has been suggested to increase DNA-binding affinity and promote transcriptional activation of downstream targets such as VEGF and glucose transporter type 1. This modification alters the conformation of HIF-1α, exposing its transcriptional activation domain and enhancing its interaction with coactivators such as p300/CBP[61]. This, in turn, promotes the assembly of the transcription complex and enhances efficient gene transcription. On the other hand, the tumor suppressor protein p53 inhibits tumorigenesis by regulating the cell cycle and inducing apoptosis in response to cellular stress. Lactylation at specific sites on p53 (e.g., K382 La) can affect its DNA-binding ability and transcriptional activation function, leading to the selective activation of target genes such as p21 and BAX, thereby promoting cell cycle arrest and apoptosis. Additionally, lactylation also affects RNA-binding proteins such as HuR, modifying lysine residues (e.g., K283 La) to enhance their affinity for specific mRNAs. This extends the half-life of these mRNAs, increasing their translation efficiency and thus regulating gene expression at the post-transcriptional level. Lactylation of transcriptional co-factors such as CBP/p300 (e.g., K1694 La) enhances their acetyltransferase activity, promoting acetylation of both histones and non-histones. This further opens chromatin structure, enhancing transcription factor binding and gene transcription activity. Furthermore, lactylation enhances the interaction between CBP/p300 and transcription factors like HIF-1α and p53, promoting stable assembly of the transcription complex and improving both the efficiency and specificity of gene expression[62].

Regulation of the tumor microenvironment

Tumor-associated macrophages: Lactylation modifies key transcription factors in tumor-associated macrophages (TAMs), promoting their polarization toward a pro-tumor M2 phenotype, thus contributing to the formation of an immunosuppressive microenvironment. Under high lactate conditions, TAMs uptake lactate, which is then catalyzed by lactate dehydrogenase (LDH) to form lactyl molecules. These lactate molecules further participate in the lactylation of lysine residues on transcription factors such as STAT6 and peroxisome proliferator-activated receptor-gamma[63]. For instance, lactylation of the lysine residue K123 on STAT6 significantly enhances its DNA-binding affinity, promoting the expression of M2-related genes such as arginase-1 and mannose receptor C-type 1. The upregulation of these genes drives TAM polarization toward the M2 phenotype, where M2 TAMs secrete anti-inflammatory cytokines such as IL-10 and transforming growth factor-β. These cytokines suppress the activity of effector T cells and NK cells, weakening the body’s anti-tumor immune response and helping tumor cells evade immune surveillance. Furthermore, lactylation of peroxisome proliferator-activated receptor-gamma (e.g., K105 La) enhances its transcriptional activity and promotes its interaction with coactivators like CBP/p300, further enhancing M2 polarization and the formation of an immunosuppressive microenvironment[26] (Figure 3).

Figure 3 Lactylation in the tumor microenvironment modulates immune and matrix remodeling functions. Elevated lactate levels, catalyzed by lactate dehydrogenase, lead to modifications of transcription factors like signal transducer and activator of transcription 6 and peroxisome proliferator-activated receptor-gamma in tumor-associated macrophages, promoting M2 polarization and the expression of immune-suppressive genes such as interleukin-10 and transforming growth factor-β. This modification inhibits the activity of effector T cells and natural killer cells, enhancing the immunosuppressive environment. Additionally, lactylation of fibroblast cell factors like nuclear factor kappa B cells and activating protein-1 promotes matrix remodeling, increasing cell migration, invasion, and metastasis, thus driving tumor progression through immune evasion and enhanced matrix degradation. NF-κB: Nuclear factor kappa B; PI3K/AKT/mTOR: Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin; H3K: Histone H3 lysine; HK2: Hexokinase 2.

Fibroblasts: In fibroblast-related studies, lactylation has been linked to altered expression and activity of MMPs, thereby enhancing matrix degradation, promoting matrix remodeling, and facilitating tumor invasion. Specifically, in a high-lactate environment, lactate enters fibroblasts via LDH and is transferred to the lysine residue K88 of MMP9 for lactylation. This modification alters the conformation of MMP9, significantly enhancing its enzymatic activity, thereby accelerating the degradation of collagen and other matrix components. Additionally, lactylation also affects transcription factors such as NF-κB and activating protein-1. By modifying lysine residues (e.g., K310 La of NF-κB p65 and K273 La of activating protein-1 c-Jun), lactylation enhances their binding affinity for MMP gene promoters, promoting MMP transcriptional expression. This process not only increases MMP secretion but also creates a more favorable environment for tumor cell migration and invasion through matrix degradation and remodeling. Furthermore, lactylation enhances interactions between fibroblasts and tumor cells, such as by increasing the lactylation of integrins, promoting cell adhesion and signaling, which further supports tumor growth and metastasis[64] (Figure 3).

RESEARCH PROGRESS AND CHALLENGES

The specific manifestations of lactylation across different cancer types

In recent years, significant progress has been made in the study of the expression profile and functional roles of lactylation in various cancer types. Lactylation plays a crucial role in metabolic reprogramming in tumor cells, and also influences tumor proliferation, migration, and immune evasion by regulating gene expression and signaling pathways. For instance, studies have shown that H3K18 La is upregulated in several cancers, including breast cancer, lung cancer, and colorectal cancer. Its high expression is closely associated with tumor invasiveness and patient prognosis[26] (Table 1).

Table 1 Clinical correlations and mechanistic implications of H3K18 lactylation in human cancers.

Cancer type	Patient cohort/method	Key prognostic findings	Mechanistic link
Breast cancer	Clinical samples (n = 76)/immunohistochemistry and The Cancer Genome Atlas analysis	High H3K18 La levels correlate significantly with advanced T, N, and M stages	Upregulation of peroxisome proliferator-activated receptor delta transcription factor, promoting cell survival
Non-small cell lung cancer	Clinical tissues (n = 125)/immunohistochemistry and Kaplan-Meier analysis	Elevated H3K18 La levels are positively correlated with poor patient prognosis	Activation of pore membrane protein 121/MYC/PD-L1 pathway, enhancing immune escape
Small cell lung cancer	ES-SCLC patients (n = 10)/immunohistochemistry and Kaplan-Meier analysis	High H3K18 La levels are associated with shorter overall survival in patients treated with immunotherapy	Transcriptional activation of neuron-derived clone 77, impairing T-cell function
Pancreatic cancer	Clinical tissues (n = 21)/western blot	H3K18 La levels positively correlate with serum tumor markers (carbohydrate antigen 19-9, carcinoembryonic antigen) and tumor size	General marker of high lactate and tumor burden

H3K18 La: 3K18 lactylation; MYC: Myelocytomatosis oncogene; PD-L1: Programmed cell death ligand 1.

In breast cancer, particularly in more advanced stages, H3K18 La levels are significantly elevated compared to adjacent non-cancerous tissues. Clinical data has demonstrated a direct correlation between higher H3K18 La expression and advanced tumor (T), node (N), and metastasis (M) stages, indicating its association with poor prognosis. This prognostic impact is mechanistically tied to H3K18 La-mediated upregulation of the transcription factor peroxisome proliferator-activated receptor delta, which in turn promotes cell survival pathways[7].

In non-small cell lung cancer, elevated pan-lysine lactylation and specifically H3K18 La levels in tumor tissues have been shown to positively correlate with poor patient prognosis, as demonstrated by survival analyses. Mechanistically, this has been linked to an H3K18 La-driven activation of the pore membrane protein 121/MYC/PD-L1 pathway, which potentiates immune escape. Similarly, in small cell lung cancer, high levels of H3K18 La were associated with shorter overall survival in patients treated with immune checkpoint inhibitors, a finding linked to the lactate-driven transcriptional activation of the immune checkpoint regulator neuron-derived clone 77[65,66].

In hepatocellular carcinoma (HCC), lactylation regulates genes associated with the cell cycle, apoptosis, and metabolism, thereby promoting tumor cell proliferation and survival. High levels of H3K18 La are linked to increased tumor proliferation and invasiveness, suggesting that lactylation plays a key role in the rapid growth and metastasis of HCC. Additionally, lactylation regulates immune cells and fibroblasts within the tumor microenvironment, promoting immune evasion and matrix remodeling, which further supports the progression of HCC[67].

Lactylation also plays a significant role in pancreatic cancer. Research has shown that lactylation regulates metabolic genes and signaling pathways, such as mTOR and AMP-activated protein kinase, promoting metabolic adaptation and survival in tumor cells. Particularly in pancreatic ductal adenocarcinoma, the high expression of lactylated key enzymes and transcription factors, such as HIF-1α and NF-κB, is associated with tumor aggressiveness and resistance, highlighting the critical role of lactylation in regulating metabolic reprogramming and immune evasion in pancreatic cancer[7]. In pancreatic cancer, H3K18 La levels have been found to positively correlate with serum tumor markers such as CA19-9 and carcinoembryonic antigen, as well as tumor size, further establishing its potential as a biomarker of disease burden.

Lactylation exhibits subtype-specific expression patterns across various tumors, reflecting its diverse roles in tumor biology. For example, in different subtypes of breast cancer, lactylation modifications vary significantly between triple negative breast cancer and hormone receptor-positive subtypes. In triple negative breast cancer, high expression of H3K18 La is closely associated with its high invasiveness and resistance to chemotherapy, whereas in hormone receptor-positive breast cancer subtypes, lactylation is more involved in regulating hormone signaling pathways, affecting hormone-dependent tumor growth. Similarly, lactylation modifications in different subtypes of non-small cell lung cancer, such as adenocarcinoma and squamous cell carcinoma, also show distinct differences. In the adenocarcinoma subtype, lactylation primarily regulates metabolic reprogramming and immune evasion mechanisms, promoting tumor survival and resistance. In contrast, in the squamous cell carcinoma subtype, lactylation is more involved in regulating genes related to cell migration and invasion, enhancing tumor metastatic potential. In colorectal cancer, lactylation modifications also show distinct patterns in tumors with varying degrees of differentiation. In well-differentiated colorectal cancer, lactylation mainly regulates genes associated with cell proliferation and apoptosis, while in poorly differentiated colorectal cancer, lactylation plays a larger role in regulating genes related to matrix degradation and cell migration, promoting tumor invasion and metastasis[68].

Future research directions

Exploration of key issues: The enzymatic mechanisms of lactylation modification are one of the central issues in current research. Although lactylation, as a novel PTM, has not yet fully defined its “writer” (lactyltransferases) and “eraser” (delactylases), studies suggest that some known enzymes, such as CBP/p300, may possess lactyltransferase activity. These enzymes catalyze the transfer of lactate groups from lactate molecules to the lysine residues of proteins, regulating protein function and gene expression. Furthermore, delactylases, such as SIRT1 and SIRT2, are thought to be involved in the reversal of lactylation modifications[21]. The regulatory networks of these enzymes involve various signaling pathways and metabolic routes, such as the PI3K/AKT/mTOR pathway and aerobic glycolysis, creating a complex regulatory network that affects tumor cell metabolism and survival. A deeper understanding of these enzymatic mechanisms and their regulatory networks will aid in comprehensively understanding the role of lactylation in tumorigenesis and progression, providing a theoretical foundation for the development of targeted therapies based on lactylation modification[33].

Tumorigenesis and progression is a dynamic process, and the changes in lactylation modification at different stages are crucial for understanding its role in tumor biology. In the early stages of tumor development, lactylation likely promotes rapid proliferation and survival of tumor cells by regulating genes involved in gene expression and cell proliferation. As the tumor progresses, lactylation modification plays an increasingly important role in regulating the tumor microenvironment, promoting angiogenesis, and facilitating immune evasion[69]. For instance, during the metastatic phase, lactylation regulates the expression and activity of MMPs, promoting matrix degradation and migration of tumor cells. Additionally, lactylation is involved in regulating the maintenance and phenotypic transformation of tumor stem cells, enhancing the tumor’s invasiveness and resistance. Therefore, studying the dynamic changes of lactylation at different stages of tumor development will not only help reveal its specific functions in tumor biology but also provide precise targets and strategies for treatment at various stages of cancer[70].

The prospects of multi-omics integrated research applications: The multi-omics integrated research approach provides a powerful tool for comprehensively analyzing the role of lactylation in cancer. Genomics can reveal mutations, copy number variations, and regulatory mechanisms of genes associated with lactylation. Transcriptomics, by analyzing the impact of lactylation on gene transcription, uncovers its specific role in gene expression regulation. Proteomics enables the identification and quantification of lactylated proteins, analyzing their role in cellular signaling and functional regulation. Metabolomics can dissect the impact of lactylation on cellular metabolic networks, revealing its specific mechanisms in metabolic reprogramming. By integrating these multi-omics data, researchers can construct a functional network of lactylation in tumors, providing a comprehensive understanding of its multi-layered role in tumorigenesis and progression. This approach not only helps reveal the molecular mechanisms of lactylation but also identifies potential regulatory nodes, providing crucial evidence for the development of precise lactylation-targeted therapeutic strategies[71].

Gene editing technologies, particularly the CRISPR/Cas9 system, provide powerful tools for studying the specific role of lactylation modifications in cancer biology. Using CRISPR/Cas9, lactylation-related genes, such as lactyltransferases and delactylases, can be precisely knocked out or knocked in to study their impact on tumor cell proliferation, migration, drug resistance, and immune evasion. For example, knocking out the CBP/p300 gene allows for direct investigation of its role in lactylation modifications and tumor cell proliferation[72]. Additionally, CRISPR activation or interference techniques can be used to modulate the expression levels of specific lactylation sites, analyzing their impact on gene expression and cellular functions. Furthermore, CRISPR/Cas9 can be employed to create tumor models specific to lactylation modifications, providing deeper insight into their role in in vivo tumorigenesis and progression. The application of these gene editing tools not only enhances our understanding of the molecular mechanisms of lactylation but also provides an experimental foundation for developing targeted therapeutic strategies based on lactylation[73,74].

Technological advances and clinical translation: A major frontier for translating lactylation research into clinical practice lies in the development of robust detection methods. Currently, lactylation is studied using a combination of approaches. For targeted validation, highly specific polyclonal and monoclonal antibodies against pan-lactyl-lysine and site-specific marks like H3K18 La are commercially available, enabling detection via western blot, immunohistochemistry, and immunofluorescence. However, the analytical sensitivity of antibody-based methods remains limited, with western blot typically requiring approximately 1 μg of total protein input for reliable detection[75]. For unbiased discovery, proteome-wide analysis relies on high-resolution liquid chromatography-tandem mass spectrometry, often coupled with antibody-based enrichment of lactylated peptides or chemical labeling strategies. Under optimized conditions, modern liquid chromatography-tandem mass spectrometry platforms are capable of detecting modified peptides at the attomole range, providing high analytical sensitivity for identifying lactylated proteins.

A significant future goal is the development of lactylation-based liquid biopsies for non-invasive cancer monitoring. This presents considerable challenges, as detecting low-abundance lactylated proteins in complex biofluids like blood plasma is difficult[76]. The current disparity in detection sensitivity between experimental systems and clinical biofluids highlights the technological gap that must be bridged for liquid-biopsy applications. However, the potential is immense. The development of sensitive immunoassays (e.g., enzyme-linked immunosorbent assay) using high-affinity monoclonal antibodies could allow for the quantification of specific lactylated proteins secreted by tumors or contained within extracellular vesicles. Overcoming these technical hurdles will be key to unlocking lactylation as a clinically actionable biomarker for diagnosis, prognosis, and therapeutic response monitoring.

CONCLUSION

Lactylation, as a novel PTM, plays a multifaceted key role in cancer biology. By modifying both histones and non-histone proteins, lactylation alters chromatin structure and regulates gene expression. It also significantly enhances tumor cell proliferation, survival, and metabolic capacity by influencing key signaling pathways, such as PI3K/AKT/mTOR and NF-κB. Lactylation plays a crucial regulatory role in the ten hallmarks of cancer, including sustained proliferative signaling, evasion of growth suppression, resistance to cell death, acquisition of replicative immortality, induction of angiogenesis, promotion of invasion and metastasis, reprogramming of energy metabolism, evasion of immune surveillance, genomic instability and mutations, and tumor-promoting inflammation. These mechanisms work together to support the rapid proliferation and adaptive evolution of tumor cells, while also enhancing their survival and dissemination capabilities in complex microenvironments, further driving malignant tumor progression.

In clinical applications, lactylation modification shows significant potential. As a biomarker, lactylation plays a crucial role in the early diagnosis and prognostic assessment of cancer. For example, high expression of histone H3K18 La in various cancers is closely associated with tumor invasiveness and poor patient prognosis, making it a potential diagnostic and prognostic marker for cancers such as breast cancer, lung cancer, and colorectal cancer. Additionally, the levels of non-histone lactylated proteins, such as PD-L1, can serve as important predictive markers for evaluating the effectiveness of immunotherapy, assisting clinicians in developing more personalized treatment plans. Targeting lactylation-related enzymes, such as LDH and CBP/p300, with specific inhibitors has emerged as a novel therapeutic approach. By inhibiting the activity of these enzymes, lactylation modification can be reduced, tumor metabolism and growth can be suppressed, the tumor microenvironment can be improved, and the effectiveness of immunotherapy can be enhanced, demonstrating a promising outlook for clinical application.

Looking ahead, in-depth research into the molecular mechanisms of lactylation modification is crucial for advancing precision medicine in cancer. A comprehensive understanding of lactylation’s specific roles across different cancer types and stages can lead to the development of more personalized and precise treatment strategies, significantly improving therapeutic outcomes and reducing resistance. To achieve this, there is an urgent need to drive innovation in detection technologies and foster interdisciplinary collaborative research. The development of high-sensitivity mass spectrometry techniques and specific lactylation antibodies is key to improving the accuracy and sensitivity of lactylation detection. Additionally, interdisciplinary collaboration, combining approaches from bioinformatics, structural biology, and gene editing technologies, will enable a more comprehensive analysis of the specific functions and regulatory networks of lactylation modifications in tumor biology. The application of single-cell multi-omics analysis methods can reveal the specific expression patterns and functional differences of lactylation across different cell subpopulations, providing more detailed molecular evidence for precise diagnosis and personalized treatment. Furthermore, gene editing technologies, particularly the CRISPR/Cas9 system, provide powerful tools for studying the specific roles of lactylation modifications in tumor biology. By precisely knocking out or knocking in lactylation-related genes, researchers can investigate their impact on tumor cell proliferation, migration, drug resistance, and immune evasion, laying a solid experimental foundation for developing targeted therapeutic strategies based on lactylation.

In conclusion, lactylation, as an emerging PTM, plays a significant regulatory role in tumor biology and holds vast potential for clinical applications. Through ongoing research and technological innovation, lactylation is poised to become a novel target for cancer diagnosis, prognostic assessment, and treatment, driving the advancement of precision medicine in oncology and improving patient outcomes and prognosis. In the future, with deeper research and enhanced interdisciplinary collaboration, lactylation modification is expected to play an even more critical role in cancer research and clinical applications, becoming a new breakthrough in cancer therapy.

ACKNOWLEDGEMENTS

The authors would like to thank the members of our respective laboratories for their insightful discussions and support. We are also grateful to our colleagues who provided critical feedback on the manuscript.