Lactate Dehydrogenase A Research Articles

A practical approach for the synthesis of lactate dehydrogenase A inhibitor GNE-140

GNE-140 is the first lactate dehydrogenase A (LDHA) inhibitor that demonstrates both sub-micromolar cellular potency and adequate pharmacokinetic properties, making it suitable for in vivo applications as a tool compound. However, the synthetic route reported by Genentech is complex, relying on transition metal catalysis and yielding low overall amounts. This study presents a practical, scalable method for constructing the core six-membered ring and quaternary carbon center of GNE-140 without transition metal catalysis, achieving a 48.5% racemic yield in a seven-step sequence, paving the way for future LDHA inhibitor development.

Death-associated protein kinase 1 prevents hypoxia-induced metabolic shift and pulmonary arterial smooth muscle cell proliferation in PAH

Pulmonary hypertension (pH) is a general term used to describe high blood pressure in the lungs from any cause. Pulmonary arterial hypertension (PAH) is a progressive, and fatal disease that causes the walls of the pulmonary arteries to tighten and stiffen. One of the major characteristics of PAH is the hyperproliferation and resistance to apoptosis of vascular cells, which trigger excessive pulmonary vascular remodeling and vasoconstriction. The death-associated protein DAP-kinase (DAPK) is a tumor suppressor and Ser/Thr protein kinase, which was previously shown to regulate the hypoxia inducible factor (HIF)-1α. Against this background, we now show that DAPK1 regulates human pulmonary smooth muscle cell (hPASMC) proliferation and energy metabolism in a HIF-dependent manner. DAPK1 expression is downregulated in pulmonary vessels and PASMCs of human and experimental PH lungs. Reduced expression of DAPK1 in hypoxia and non-hypoxia PAH-PASMCs correlates with increased expression of HIF-1/2α. RNA interference-mediated depletion of DAPK1 leads to fundamental metabolic changes, including a significantly decreased rate of oxidative phosphorylation associated with enhanced expression of both HIF-1α and HIF-2α and glycolytic enzymes, as hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), and an integrator between the glycolysis and citric acid cycle, pyruvate dehydrogenase kinase 1 (PDK1). DAPK1 ablation in healthy donor hPASMCs leads to an increase in proliferation, while its overexpression provides the opposite effects. Together our data indicate that DAPK1 serves as a new inhibitor of the pro-proliferative and glycolytic phenotype of PH in PASMCs acting via HIF-signaling pathway.

Mechanism of jianxin granules in the treatment of heart failure based on proteomics and metabolomics

BackgroundHeart failure (HF) is associated with high mortality and rehospitalization rates, highlighting the need for novel therapeutic approaches. Jianxin (JX) granules, a Traditional Chinese Medicine formulation, have been patented for the treatment of HF. However, the specific therapeutic effects and underlying mechanisms of JX granules have not been fully elucidated. This study aimed at investigating the effects and mechanism of JX granules in the treatment of HF based on proteomics and metabolomic profiling.MethodsHF model was established in rats by ligation of left coronary artery. The successfully modeled rats were randomly divided into three groups: the model group, the JX granules group, and Sacubitril/Valsartan (S/V) group. Four weeks after treatment, left ventricular (LV) function was evaluated via echocardiography. LV fibrosis and apoptosis were examined through histological analyses, while mitochondrial morphology was assessed using transmission electron microscopy. Quantitative assessment of oxidative stress was also conducted. Proteomics was used to identify the differentially expressed proteins and potential pathways. Metabolomics was utilized to elucidate the variations in metabolism. Then western blotting and in vitro analyses were performed.ResultsA rat model of HF was established, evidenced by a decrease in left ventricular ejection fraction (LVEF), stroke volume (SV), and left ventricular fractional shortening (LVFS), alongside diminished adenosine triphosphate (ATP) content, elevated oxidative stress, augmented apoptosis, and disrupted pyruvate metabolism. Treatment with JX granules ameliorated these effects, improving systolic function, reducing ventricular chamber size, and increasing LVEF, SV, and LVFS, as assessed by echocardiography. Additionally, JX granules attenuated cardiac fibrosis and improved mitochondrial structure, as evidenced by less vacuolation and clearer mitochondrial cristae, when compared to the model group. The treatment also regulated apoptosis-related protein expression, partially reversing the increase in cleaved Caspase-9, cleaved Caspase-3, and Bax and the suppression of Bcl-2 observed in the heart failure rats. All of these effects were similar to S/V. Proteomic and metabolomic analyses identified key differential genes, such as triosephosphate isomerase 1 (TPI1), lactate dehydrogenase B (LDHB), pyruvate kinase M (PKM), protein kinase B (Akt), Pyruvate Dehydrogenase Beta (PDHB) and lactate dehydrogenase A (LDHA), as well as vital pathways including carbon metabolism, the PI3K-Akt signaling pathway, pyruvate metabolism, and HIF-1α signaling pathway. Moreover, JX granules mitigated oxidative stress, inhibited apoptosis, and activated Akt in H9c2 cells exposed to angiotensin II, which could be reversed by the PI3K inhibitor LY294002.ConclusionJX granules improve HF in parallel to the efficacy of S/V, at least in part, through enhancing pyruvate metabolism, inhibiting oxidative stress and activating PI3K/Akt pathway.

Lactate Dehydrogenase A Is a Novel Positive Regulator of Vascular Smooth Muscle Cell Ferroptosis During Aortic Dissection.

Aims: Vascular smooth muscle cell (VSMC) ferroptosis is a pivotal event in the process of aortic dissection (AD), and a number of agents have a protective role against AD by inhibiting VSMC ferroptosis. While glycolysis is an ancient pathway related to almost all biological processes, its precise involvement in VSMC ferroptosis and AD remains unclear. Results: In this study, bioinformatics analysis revealed that glycolysis-related molecules and pathways were involved in VSMC ferroptosis and AD. We focused on the key enzyme of glycolysis, lactate dehydrogenase A (LDHA), and found that LDHA overexpression promoted ferroptosis and lipid peroxidation in cystine deprivation- or imidazole ketone erastin-treated VSMCs and vice versa. Clinical specimens showed a negative correlation between elevated LDHA levels in dissected aortae and ferroptosis-related molecules glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), and ferroptosis suppressor protein 1 (FSP1). In VSMC ferroptosis, LDHA overexpression led to the suppression of GPX4, SLC7A11, and FSP1. Furthermore, the interaction between LDHA and nuclear factor (erythroid-derived 2)-like 2 (NRF2) was identified, and the overexpression or agonist of NRF2 reversed the contribution of LDHA on VSMC ferroptosis and lipid peroxidation. Innovation and Conclusion: These results highlight a significant association between LDHA and VSMC ferroptosis in AD development mediated through NRF2. These findings present LDHA as a potential target for AD intervention by inhibiting its expression. Antioxid. Redox Signal. 00, 000-000.

PDCD6 regulates lactate metabolism to modulate LC3-associated phagocytosis and antibacterial defense

LC3-associated phagocytosis (LAP) is critical in host defense against invading pathogens, but the molecular mechanism for LAP activation is still unclear. Here, we find programmed cell death 6 (PDCD6) as a negative regulator of LAP. PDCD6 deficiency in mice and macrophages induces enhanced bactericidal activity and LAP formation. In parallel, lactate dehydrogenase A (LDHA) activity and lactate production is induced in macrophages challenged with bacteria, Zymosan or Pam3CSK4, while genetic ablation or pharmacological inhibition of LDHA reduces lactate levels and impairs bactericidal activity in vivo and in vitro. Mechanistically, PDCD6 interacts with LDHA to downregulate lactate metabolism, leading to reduced RUBCN lactylation at lysine33 (K33). By contrast, PDCD6-deficiency increases RUBCN lactylation, thereby promotes RUBCN interaction with VPS34, LAP formation, and protective responses. Our results thus suggest a PDCD6-LDHA-lactate-RUBCN axis of innate immunity regulation that may both contribute to protection from infectious diseases and serve as targets for therapeutic development.

Diminished lactate utilization in LDHB-deficient neurons leads to impaired long-term memory retention

Neurons' high energy demands for processing, transmitting, and storing information in the brain necessitate efficient energy metabolism to maintain normal neuronal function. The astrocyte-neuron lactate shuttle (ANLS) hypothesis suggests neurons preferentially use lactate from astrocytes over glucose for energy. This study investigated lactate dehydrogenase B (LDHB), which preferentially converts lactate to pyruvate, in neuronal energy metabolism and cognitive function. LDHB-deficient neurons showed reduced lactate-driven energy metabolism in culture, while LDHB-deficient brains accumulated lactate, both indicating decreased lactate utilization. This reduced lactate utilization was correlated with impaired long-term memory in LDHB-deficient mice, while short-term memory remained unaffected and overall neuropathology was only mildly disturbed. Unexpectedly, LDHB-deficient neurons maintain stable energy metabolism under physiological glucose conditions, indicating the presence of lactate dehydrogenase (LDH) activity in LDHB-deficient neurons. The observation of lactate dehydrogenase A (LDHA), which preferentially converts pyruvate to lactate but can also catalyze the reverse reaction less efficiently, in LDHB-deficient neurons may explain their stable energy metabolism and reduced lactate utilization. This study challenges the established concept of strict LDH isoform compartmentalization in brain cells, questioning the exclusive presence of LDHB in neurons and suggesting a more flexible neuronal metabolic profile than previously assumed by the ANSL hypothesis.

Dipeptide alanine-glutamine ameliorates retinal neurodegeneration in an STZ-induced rat model.

Diabetic retinopathy (DR) is a common complication of diabetes. Retinal neuronal degeneration is an early event in DR, indicated by the declined electroretinogram (ERG). Dipeptide alanine-glutamine (Ala-Gln) is widely used as a nutritional supplement in the clinic and has anti-inflammatory effects on the gastrointestinal system. Studies also reported that glutamine has beneficial effects on diabetes. This study aimed to investigate the possible therapeutic effects of Ala-Gln in diabetic retinal neurodegeneration and to delineate its mechanism of action. The Streptozotocin (STZ)-induced rat model was used as a DR model. ERG was used to measure the neuronal function of the retina. Western blot analysis was performed to test the expression of proteins. Immunofluorescence staining was used for the detection and localization of proteins. In diabetic rats, the amplitudes of ERG were declined, while Ala-Gln restored the declined ERG. Retinal levels of inflammatory factors were significantly decreased in Ala-Gln-treated diabetic rats. Ala-Gln mitigated the declined levels of glutamine synthetase and ameliorated the upregulated levels of glial fibrillary acidic protein (GFAP) in diabetic retinas. Moreover, Ala-Gln upregulated the glycolytic enzymes pyruvate kinase isozymes 2 (PKM2), lactate dehydrogenase A (LDHA) and LDHB and stimulated the mTOR signaling pathway in diabetic retinas. The mitochondrial function was improved after the treatment of Ala-Gln in diabetic retinas. Ala-Gln ameliorates retinal neurodegeneration by reducing inflammation and enhancing glucose metabolism and mitochondrial function in DR. Therefore, manipulation of metabolism by Ala-Gln may be a novel therapeutic avenue for retinal neurodegeneration in DR.

Macrophage-Specific Lactate Dehydrogenase Expression Modulates Inflammatory Function In Vitro.

In acute kidney injury, macrophages play a major role in regulating inflammation. Classically activated macrophages (M1) undergo drastic metabolic reprogramming during their differentiation and upregulate the aerobic glycolysis pathway to fulfill their pro-inflammatory functions. NAD+ regeneration is crucial for the maintenance of glycolysis and the most direct pathway by which this occurs is via the fermentation of pyruvate to lactate, catalyzed by lactate dehydrogenase A (LDHA). Our previous study determined that LDHA is predominantly expressed in the proximal segments of the nephron in the mouse kidney and increases with hypoxia. This study investigates the potential of LDHA as a therapeutic target for inflammation by exploring its role in macrophage function in vitro. Bone-marrow-derived macrophages (BMDMs) were isolated from myeloid-specific LDHA knockout mice derived from crossbreeding LysM-Cre transgenic mice and LDHA floxed mice. RNA sequencing and LC-MS/MS metabolomics analyses were used in this study to determine the effect of LDHA deletion on BMDM following stimulation with IFN-γ. LDHA deletion in IFN-γ BMDMs resulted in a significant alteration of the macrophage activation and functional pathways, and change in glycolytic, cytokine, and chemokine gene expression. Metabolite concentrations associated with pro-inflammatory macrophage profiles were diminished while anti-inflammatory-associated ones were increased in LDHA KO BMDMs. Glutamate and amino sugars metabolic pathways were significantly affected by the LDHA deletion. A combined muti-omics analysis highlighted changes in Rap1 signaling, cytokine-cytokine receptor interaction, focal adhesion, and MAPK signaling metabolism pathways. Deletion of LDHA in macrophages results in a notable reduction in the pro-inflammatory profile and concurrent upregulation of anti-inflammatory pathways. These findings suggest that LDHA could serve as a promising therapeutic target for inflammation, a key contributor to the pathogenesis of acute kidney injury.

Lactate dehydrogenase A is a diagnostic biomarker associated with immune infiltration, m6A modification and ferroptosis in endometrial cancer.

Lactate dehydrogenase A (LDHA) has been confirmed as a tumor promoter in various cancers, but its role in endometrial cancer remains unclear. The Cancer Genome Atlas (TCGA), quantitative real-time polymerase chain reaction and the Human Protein Atlas were utilized to analyzed the LDHA expression in EC. The LDHA levels of patients with different clinical features were compared based on the TCGA cohort. The Genome Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis of LDHA-related genes were conducted by R language. The influence of LDHA knockdown on cell proliferation, apoptosis, migration and invasion was detected by in vitro experiment. The relationship between LDHA expression and immune infiltration was explored by Tumor Immune Estimation Resource 2.0 and Gene Expression Profiling Interactive Analysis. The association of LDHA level with N6-methyladenosine (m6A) modification and ferroptosis was investigated based on the TCGA-UCEC and the GEO cohort. The LDHA was overexpressed in EC tissues and EC cell lines, and had high predictive accuracy for the EC diagnosis. The LDHA level was associated with age, histological type, histologic grade, and radiation therapy. LDHA-related genes participated in multiple biological functions and signaling pathways. LDHA downregulation significantly promoted cell apoptosis and inhibited the proliferation, migration, and invasion of EC cells. LDHA expression was connected to multiple tumor-infiltrating lymphocytes (TILs), m6A-related genes, and ferroptosis-related genes. LDHA has the potential to work as an EC biomarker associated with TILs, m6A modification, and ferroptosis in EC.

Uric acid mediates kidney tubular inflammation through the LDHA/ROS/NLRP3 pathway

ABSTRACT Purpose Hyperuricemia (HUA) is an important factor leading to chronic kidney disease (CKD). The kidney tubular inflammatory response is activated in HUA. This study aimed to investigate whether lactate dehydrogenase A (LDHA) is involved in mediating uric acid-induced kidney tubular inflammatory response. Methods In vivo, an HUA mouse model was established by continuous intraperitoneal injection of potassium oxonate (PO) for one week. A total of 18 C57BL/6J male adult mice were divided into three groups: control group, HUA group, and HUA+oxamate group, with six mice in each group. Oxamate was intraperitoneally injected into the mice one hour after PO injection. In vitro, an HUA model was simulated by stimulating HK-2 cells with uric acid. Oxamate and tempol inhibited LDHA and reactive oxygen species (ROS) in HK-2 cells. Results In HUA mice, blood uric acid levels were significantly elevated. LDHA in kidney tubular cells was significantly increased in both in vivo and in vitro HUA models, accompanied by an increase in kidney tubular inflammation and ROS. Mechanistically, LDHA mediates uric acid-induced inflammation to kidney tubular cells through the ROS/NLRP3 pathway. Pharmacologic inhibition of LDHA or ROS in kidney tubular cells can significantly ameliorate inflammation response caused by uric acid. Conclusions LDHA in kidney tubular cells significantly was increased in HUA models. LDHA mediates kidney inflammation response induced by uric acid through the ROS/NLRP3 pathway. This study may provide a new intervention target for preventing kidney tubular inflammation caused by uric acid.

Ginsenoside compound K restrains hepatic fibrotic response by dual-inhibition of GLS1 and LDHA

BackgroundLiver fibrosis is a dynamic process marked by the accumulation of extracellular matrix due to hepatic stellate cells (HSCs) activation. Ginsenoside compound K (CK), a rare derivative of its parent ginsenosides, is known to significantly ameliorate metabolic disorders. PurposeThe aim of this study was to elucidate the protective effects of CK against liver fibrosis with a focus on metabolic regulation. MethodsWe established liver fibrosis models in mice using carbon tetrachloride (CCl4) challenge, bile duct ligation, or a methionine-choline deficient diet, with continuous oral administration of CK at specified doses and intervals. Simultaneously, we examined the impact of CK on metabolic regulation in cultured HSCs and investigated the associated mechanisms. ResultsCK was found to alleviate liver injury and curb fibrotic responses in mouse models, as well as decrease elevated levels of liver enzyme. Metabolomic analysis in vitro highlighted the crucial roles of pyruvate and glutamine metabolism in metabolic remodeling. Immunohistochemical staining indicated significantly elevated expressions of lactate dehydrogenase A (LDHA) (p = 0.014) and glutaminase 1 (GLS1) (p = 0.024) in liver cirrhosis patients. Comparable alterations were noted in the liver of model mice and in cultured HSCs. Molecular docking and bio-layer interferometry demonstrated that CK interacts with and inhibits the activities of LDHA and GLS1. As expected, CK attenuated glycolysis and glutaminolysis, reducing HSC growth dependently on lactate and α-ketoglutarate (α-KG). Upon HSC activation, metabolism is reprogrammed with Myc as a key regulator, transcriptionally controlling LDHA, GLS1, and glutamine transporters SLC1A5 and SLC38A5. CK inhibited Myc induction, integrating glycolysis and glutaminolysis regulation to counteract the fibrotic response. ConclusionCK inhibited LDHA and GLS1 activities, thereby inhibiting hepatic fibrosis. These findings offer new insights into the role of ginsenosides in liver protection, especially regarding metabolic disorders.

Influenza A virus-induced glycolysis facilitates virus replication by activating ROS/HIF-1α pathway

As a highly contagious acute respiratory disease, influenza A virus (A/WSN/1933) poses a huge threat to human health and public health. influenza A virus proliferation relies on glucose metabolism in host cells, yet the effects of influenza A virus on glucose metabolism and the underlying molecular mechanisms remain unclear. Here, we created models of WSN virus-infected mice and A549 cells, along with analyzing metabolomics and transcriptomics data, to investigate how WSN virus infection affects host cell glucose metabolism and specific mechanisms. Analysis of metabolites and gene expression showed that WSN virus infection triggers glycolysis in A549 cells, with notable upregulation of hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), hypoxia-inducible factor-1 alpha (HIF-1α), and elevated lactate levels. Additionally, it leads to mitochondrial impairment and heightened reactive oxygen species (ROS) generation. Elevated levels of glucose may enhance the replication of WSN virus, whereas inhibitors of glycolysis can reduce it. Enhancement of HIF-1α activation facilitated replication of WSN virus through stimulation of lactate synthesis, with the primary influence of glycolysis on WSN virus replication being mediated by ROS/HIF-1α signaling. Mice given HIF-1α inhibitor PTX-478 or glycolysis inhibitor 2-Deoxyglucose (2-DG) exhibited reduced lactate levels and decreased WSN virus replication, along with mitigated weight loss and lung damage. In summary, WSN virus-induced glycolysis has been demonstrated to enhance virus replication through the activation of the ROS/HIF-1α pathway, suggesting potential new targets for combating the virus.

Immunoliposomes for Neuroblastoma: Review of the Past Experience and Design of a Novel Nanoparticle.

High-risk/refractory neuro-blastoma (NBL) treatments include anti-GD2-monoclonal antibodies (mAbs). Several immunoliposomes (ILs) covered with anti-GD2-mAbs (GD2-ILs) have been tested pre-clinically. We aimed to review literature on GD2-IL for characteristics of nanoparticles/payloads, conjugation of mAb/fragments and preclinical data, as well as to explore the feasibility of a recently proposed GD2-IL loaded with the antimetabolite oxamate. Initial PubMed search was generalized for immunoliposomes in cancer. Further search was focused on papers for GD2-IL [keywords: "Immunoliposomes and cancer (or neuroblastoma)"]. There were 811 results on "immunoliposomes"; >50% were on "immunoliposomes, cancer" (n=439, June 2024). Seventeen items resulted from "immunoliposomes, neuroblastoma" (one was "publishers' correction"). Sixteen GD2-IL references were reviewed (1993-current). The mean±SD GD2-ILs size was 124.8±31 nm (range=86-171). Six papers described GD2-ILs with DNA-damaging agents [doxorubicin (n=4), etoposide (n=1), irinotecan+HDAC inhibitor (n=1)]. Other payloads included: fenretinide (n=4 papers), C-myb antisense (n=2), survivin inhibitor (n=1), tyrosine kinase inhibitor (n=1), IL15 (n=1), and oxamate (n=1). These 9 drug-loads included both hydrophilic and hydrophobic molecules. Except for IL15 and C-myb antisense with high molecular weights (MWs), and oxamate with low MW, the remaining compounds had comparable MWs (496±100 g/mol, range=349-588.6). The overall encapsulation efficiency was 66.2±25.6%. There were 17-30 mAb molecules attached to an IL with PEGylation. Experiments with GD2-positive/GD2-negative cells demonstrated selective efficacy/tropism of GD2-ILs. Mouse models confirmed efficacy, GD2-specific tumor accumulation, decreased toxicity, and improved pharmacokinetic-pharmacodynamics. PEGylated anti-GD2-IL may allow NBL tropism. A size of approximately 100 nm could allow vascular permeability and packaging of oxamate in amounts needed for profound/selective lactate dehydrogenase-A inhibition. Thus, oxamate-loaded GD2-ILs may allow exploring the great translational potential of Warburg effect inhibition in GD2-positive cancers.

ST3GAL4 promotes tumorigenesis in breast cancer by enhancing aerobic glycolysis.

Sialyltransferases are enzymes that play a crucial role in regulating cancer progression by modifying glycoproteins through sialylation. In particular, the ST3 beta-galactoside alpha-2,3-sialyltransferase 4 (ST3GAL4) enzyme is known to be upregulated in breast cancer, but its specific biological functions have not been fully understood. This study aimed to investigate the impact and mechanisms of ST3GAL4 on aerobic glycolysis in breast cancer. We examined ST3GAL4 expression in tumor tissue samples and breast cancer cell lines and also manipulated ST3GAL4 expression in breast cancer cells using lentivirus transduction. The study evaluated cellular processes such as cell viability, cell cycle progression, and aerobic glycolysis by measuring parameters like extracellular acidification rate, glucose uptake, lactate production, and lactate dehydrogenase A (LDHA) expression. We found that ST3GAL4 expression was consistently increased in tumor tissues and breast cancer cell lines. High ST3GAL4 expression was associated with a poor prognosis for patients with breast cancer. Inhibiting ST3GAL4 expression decreased cell viability, disrupted cell cycle progression, and reduced aerobic glycolysis and LDHA expression. Furthermore, suppressing ST3GAL4 expression in animal models reduced tumor growth and cell proliferation. Conversely, overexpressing ST3GAL4 promoted cell viability and cell cycle progression, but these effects were reversed when an inhibitor of aerobic glycolysis was used. The study provided evidence in cells and animal models that ST3GAL4 promotes tumorigenesis in breast cancer by enhancing aerobic glycolysis. These findings suggest that targeting ST3GAL4 may be a potential strategy for the treatment of breast cancer.

SPINK4 modulates inhibition of glycolysis against colorectal cancer progression.

Dysregulation of glycolysis is frequently linked to aggressive tumor activity in colorectal cancer (CRC). Although serine peptidase inhibitor, Kazal type 4 (SPINK4) has been linked to CRC, its exact linkage to glycolytic processes and gene expression remains unclear. Differentially expressed genes (DEGs) were screened from two CRC-related datasets (GSE32323 and GSE141174), followed by expression and prognostic analysis of SPINK4. In vitro techniques such as flow cytometry, western blotting, transwell assay, and quantitative real-time polymerase chain reaction (qRT-PCR) were used to assess SPINK4 expression in CRC cells. Its effects on apoptosis, glycolysis, and the cell cycle were also investigated. Finally, the impact of SPINK4 overexpression on tumor development was assessed using a xenograft model, while histological and immunohistochemical analyses characterized SPINK4 expression patterns in CRC tissues. SPINK4 expression was downregulated in CRC, correlating with poor patient prognosis. In vitro assays confirmed that overexpression of SPINK4 reduced CRC cell proliferation, invasion, and migration, while its knockdown promoted these processes and caused G1 arrest. SPINK4 also regulated apoptosis by altering caspase activation and Bcl-2 expression. Besides, SPINK4 overexpression altered glycolytic activity, reduced 2-Deoxy-D-glucose (2-DG) absorption, and controlled critical glycolytic enzymes, resulting in alterations in metabolic pathways, whereas SPINK4 knockdown reversed this effect. SPINK4 overexpression significantly reduced tumor volume in vivo, indicating its inhibitory role in carcinogenesis. Moreover, high expression of SPINK4, hexokinase 2 (HK2), glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA), and pyruvate kinase M2 (PKM2) was observed in CRC tissues. As a key inhibitor of glycolytic metabolism in CRC, SPINK4 promises metabolic intervention in CRC therapy due to its impact on tumor growth and cell proliferation.

RBM15 drives the progression of lung adenocarcinoma by regulating N6-methyladenosine-mediated LDHA mRNA stability

Abnormal N6-methyladenosine (m6A) methylation in RNA plays a pivotal role in the pathogenesis of many types of tumors by influencing mRNA metabolism, alternative splicing, translocation, stability and translation. However, the specific regulators and underlying mechanisms of m6A modification in the progression of lung adenocarcinoma are not well understood. In this study, we analyzed the RNA-seq transcriptome data downloaded from The Cancer Genome Atlas (TCGA) database, and identified “m6A writer” RNA binding motif protein 15 (RBM15) expression was significantly elevated in lung adenocarcinoma (LUAD) biopsies, and the higher RBM15 levels were correlated with the poorer overall survival (OS) of LUAD patients. Further study confirmed RBM15 was prominently expressed in LUAD tissues and cell lines. Moreover, silencing RBM15 in PC9 and H1299 cells reduced cell proliferation both in vitro and in vivo, while overexpression of RBM15 in A549 cells promoted cell growth. Mechanistically, lactate dehydrogenase A (LDHA) acted as a downstream target of RBM15. RBM15-mediated m6A modification of LDHA mRNA enhanced its stability to exert an oncogenic role in LUAD. Taken together, our findings suggest that the RBM15/LDHA axis might be a novel and promising therapeutic target for LUAD.

Glycolysis-mTORC1 crosstalk drives proliferation of patient-derived endometrial cancer spheroid cells with ALDH activity

Cancer stem cells are associated with aggressive phenotypes of malignant tumors. A prominent feature of uterine endometrial cancer is the activation of the PI3K–Akt–mTOR pathway. In this study, we present variations in sensitivities to a PI3K–Akt–mTORC1 inhibitor among in vitro endometrial cancer stem cell-enriched spheroid cells from clinical specimens. The in vitro sensitivity was consistent with the effects observed in in vivo spheroid-derived xenograft tumor models. Our findings revealed a complementary suppressive effect on endometrial cancer spheroid cell growth with the combined use of aldehyde dehydrogenase (ALDH) and PI3K–Akt inhibitors. In the PI3K–Akt–mTORC1 signaling cascade, the influence of ALDH on mTORC1 was partially channeled through retinoic acid-induced lactate dehydrogenase A (LDHA) activation. LDHA inhibition was found to reduce endometrial cancer cell growth, aligning with the effects of mTORC1 inhibition. Building upon our previous findings highlighting ALDH-driven glycolysis through GLUT1 in uterine endometrial cancer spheroid cells, curbing mTORC1 enhanced glucose transport via GLUT1 activation. Notably, elevated LDHA expression correlated with adverse clinical survival and escalated tumor grade, especially in advanced stages. Collectively, our findings emphasize the pivotal role of ALDH–LDHA–mTORC1 cascade in the proliferation of endometrial cancer. Targeting the interaction between mTORC1 and ALDH-influenced glycolysis holds promise for developing novel strategies to combat this aggressive cancer.

USP4 promotes PTC progression by stabilizing LDHA and activating the MAPK and AKT signaling pathway.

Ubiquitin-specific protease 4 (USP4) has been identified as a promising oncogenic factor implicated in various human malignancies. However, the exact biological functions and underlying mechanisms of USP4 in the progression of papillary thyroid carcinoma (PTC) remain elusive. In this study, we observed a marked upregulation of USP4 expression in PTC tumor tissues. Elevated levels of USP4 were significantly correlated with aggressive clinicopathological features and poor prognosis. Functional assays for loss-of-function demonstrated that silencing USP4 hindered the proliferation of PTC cells. Furthermore, our investigation revealed a specific interaction between USP4 and lactate dehydrogenase A (LDHA), wherein USP4 played a crucial role in stabilizing LDHA protein levels via deubiquitination in PTC cells. Notably, this study demonstrated that USP4 promotes PTC proliferation by modulating the MAPK and AKT signaling pathways. In summary, our findings elucidate the critical involvement of the USP4/LDHA axis in driving PTC progression through the modulation of MAPK and AKT pathways, thereby identifying USP4 as a potential therapeutic target for the treatment of PTC.

TRIM33 promotes glycolysis through regulating P53 K48-linked ubiquitination to promote esophageal squamous cell carcinoma growth

Esophageal squamous cell carcinoma (ESCC) is a common fatal malignant tumor of the digestive tract; however, its pathogenic mechanism is unknown and lacks specific molecular diagnosis and treatment. Therefore, it is particularly important to identify new tumor biomarkers to enhance the early diagnosis and molecular-targeted therapy of ESCC. Here, we found that the E3 ubiquitin ligase Tripartitemotif-containing33 (TRIM33) is highly expressed in ESCC tissues and cell lines, and is associated with adverse clinical outcomes. We determined that TRIM33 drives aerobic glycolysis to promote tumor growth in vivo and in vitro. In terms of mechanism, TRIM33 binds to p53 to inhibit its stability and promote the expression of downstream glycolysis target genes GLUT1, HK2, PKM2, and LDHA. In addition, TRIM33 promotes the polyubiquitination of P53 K48-linked and proteasome degradation. Further studies have shown that the K351 site of P53 is the key site mediating the ubiquitination of P53 K48-linked to promote aerobic glycolysis in ESCC and tumor cell growth. Our results reveal that the TRIM33-P53 signal axis regulates glycolysis during ESCC and may provide a new perspective for the diagnosis and treatment of ESCC.

CircMETTL3-156aa reshapes the glycolytic metabolism of macrophages to promote M1 polarization and induce cytokine storms in sHLH

Persistent macrophage activation and cytokine storms are critical causes for the rapid disease progression and high mortality rate of Secondary Hemophagocytic lymphohistiocytosis (sHLH). Identification of key regulatory factors that govern the activation of macrophages is vital. Plasma exosomal circular RNAs (circRNAs) are considered important biomarkers and potential therapeutic targets for various diseases, however, their function in sHLH is still unclear. In this study, we demonstrated for the first time that circMETTL3, derived from METTL3, is upregulated in sHLH patient plasma exosomes, which may plays an important role in the diagnosis of sHLH. Significantly, we also revealed that a novel peptide encoded by circMETTL3, METTL3-156aa, is an inducer of M1 macrophage polarization, which is responsible for the development of cytokine storms during sHLH. We then identified that METTL3-156aa binding with lactate dehydrogenase A (LDHA) and promotes M1 macrophage polarization by enhancing macrophage glycolysis. Additionally, the glycolysis metabolite lactate upregulates the cleavage factor SRSF10 expression by lactylation. This results in increased splicing of the pre-METTL3 mRNA, leading to an enchance in the production of cirMETTL3. Therefore, our results suggest that the circMETTL3/METTL3-156aa/LDHA/Lactate/SRSF10 axis forms a positive feedback loop and may be a novel therapeutic target for the treatment of sHLH.