The 419th Aspartic Acid of Neural Membrane Protein Enolase 2 Is a Key Residue Involved in the Axonal Growth of Motor Neurons Mediated by Interaction between Enolase 2 Receptor and Extracellular Pgk1 Ligand.

Neuron-specific Enolase 2 (Eno2) is an isozyme primarily distributed in the central and peripheral nervous systems and neuroendocrine cells. It promotes neuronal survival, differentiation, and axonal regeneration. Recent studies have shown that Eno2 localized on the cell membrane of motor neurons acts as a receptor for extracellular phosphoglycerate kinase 1 (ePgk1), which is secreted by muscle cells and promotes the neurite outgrowth of motor neurons (NOMN). However, interaction between Eno1, another isozyme of Enolase, and ePgk1 failed to return the same result. To account for the difference, we constructed seven point-mutations of Eno2, corresponding to those of Eno1, and verified their effects on NOMN. Among the seven Eno2 mutants, eno2-siRNA-knockdown NSC34 cells transfected with plasmid encoding the 419th aspartic acid mutated into serine (Eno2-[D419S]) or Eno2-[E420K] showed a significant reduction in neurite length. Moreover, the Eno2-ePgk1-interacted synergic effect on NOMN driven by Eno2-[D419S] was more profoundly reduced than that driven by Eno2-[E420K], suggesting that D419 was the more essential residue involved in NOMN mediated by Eno2-ePgk1 interaction. Eno2-ePgk1-mediated NOMN appeared to increase the level of p-Cofilin, a growth cone collapse marker, in NSC34 cells transfected with Eno2-[D419S] and incubated with ePgk1, thereby inhibiting NOMN. Furthermore, we conducted in vivo experiments using zebrafish transgenic line Tg(mnx1:GFP), in which GFP is tagged in motor neurons. In the presence of ePgk1, the retarded growth of axons in embryos injected with eno2-specific antisense morpholino oligonucleotides (MO) could be rescued by wobble-eno2-mRNA. However, despite the addition of ePgk1, the decreased defective axons and the increased branched neurons were not significantly improved in the eno2-[D419S]-mRNA-injected embryos. Collectively, these results lead us to suggest that the 419th aspartic acid of mouse Eno2 is likely a crucial site affecting motor neuron development mediated by Eno2-ePgk1 interaction, and, hence, mutations result in a significant reduction in the degree of NOMN in vitro and axonal growth in vivo.

Single-cell dissection reveals promotive role of ENO1 in leukemia stem cell self-renewal and chemoresistance in acute myeloid leukemia.

BACKGROUND: Quiescent self-renewal of leukemia stem cells (LSCs) and resistance to conventional chemotherapy are the main factors leading to relapse of acute myeloid leukemia (AML). Alpha-enolase (ENO1), a key glycolytic enzyme, has been shown to regulate embryonic stem cell differentiation and promote self-renewal and malignant phenotypes in various cancer stem cells. Here, we sought to test whether and how ENO1 influences LSCs renewal and chemoresistance within the context of AML. METHODS: We analyzed single-cell RNA sequencing data from bone marrow samples of 8 relapsed/refractory AML patients and 4 healthy controls using bioinformatics and machine learning algorithms. In addition, we compared ENO1 expression levels in the AML cohort with those in 37 control subjects and conducted survival analyses to correlate ENO1 expression with clinical outcomes. Furthermore, we performed functional studies involving ENO1 knockdown and inhibition in AML cell line. RESULTS: We used machine learning to model and infer malignant cells in AML, finding more primitive malignant cells in the non-response (NR) group. The differentiation capacity of LSCs and progenitor malignant cells exhibited an inverse correlation with glycolysis levels. Trajectory analysis indicated delayed myeloid cell differentiation in NR group, with high ENO1-expressing LSCs at the initial stages of differentiation being preserved post-treatment. Simultaneously, ENO1 and stemness-related genes were upregulated and co-expressed in malignant cells during early differentiation. ENO1 level in our AML cohort was significantly higher than the controls, with higher levels in NR compared to those in complete remission. Knockdown of ENO1 in AML cell line resulted in the activation of LSCs, promoting cell differentiation and apoptosis, and inhibited proliferation. ENO1 inhibitor can impede the proliferation of AML cells. Furthermore, survival analyses associated higher ENO1 expression with poorer outcome in AML patients. CONCLUSIONS: Our findings underscore the critical role of ENO1 as a plausible driver of LSC self-renewal, a potential target for AML target therapy and a biomarker for AML prognosis.

O-GlcNAcylation of enolase 1 serves as a dual regulator of aerobic glycolysis and immune evasion in colorectal cancer.

Aerobic glycolysis and immune evasion are two key hallmarks of cancer. However, how these two features are mechanistically linked to promote tumor growth is not well understood. Here, we show that the glycolytic enzyme enolase-1 (ENO1) is dynamically modified with an O-linked ß-N-acetylglucosamine (O-GlcNAcylation), and simultaneously regulates aerobic glycolysis and immune evasion via differential glycosylation. Glycosylation of threonine 19 (T19) on ENO1 promotes its glycolytic activity via the formation of active dimers. On the other hand, glycosylation of serine 249 (S249) on ENO1 inhibits its interaction with PD-L1, decreases association of PD-L1 with the E3 ligase STUB1, resulting in stabilization of PD-L1. Consequently, blockade of T19 glycosylation on ENO1 inhibits glycolysis, and decreases cell proliferation and tumor growth. Blockade of S249 glycosylation on ENO1 reduces PD-L1 expression and enhances T cell-mediated immunity against tumor cells. Notably, elimination of glycosylation at both sites synergizes with PD-L1 monoclonal antibody therapy to promote antitumor immune response. Clinically, ENO1 glycosylation levels are up-regulated and show a positive correlation with PD-L1 levels in human colorectal cancers. Thus, our findings provide a mechanistic understanding of how O-GlcNAcylation bridges aerobic glycolysis and immune evasion to promote tumor growth, suggesting effective therapeutic opportunities.

Molecular Cloning, Prokaryotic Expression, and Immunological Characterization of ß-Enolase from Grass Carp (Ctenopharyngodon idella).

ß-Enolase is a cross-allergen commonly found in fungi, plants, and aquatic products. Although studies on the allergenicity of fish enolase have been reported in recent years, they are still limited to a few species of marine fish. Therefore, the detection of freshwater fish in the food industry requires more studies of the molecular characterization as well as the allergenicity of enolase. In this study, the nucleotide sequence of ß-enolase from grass carp was obtained by molecular cloning technology. Structural domain analysis showed that it contained the characteristic structural domains of the enolase superfamily, and homology analysis indicated that enolases are highly conserved evolutionarily. Recombinant ß-enolase was obtained by prokaryotic expression, and its allergenicity was assessed by ß-enolase-sensitized mice, which confirmed the ability of ß-enolase to trigger an allergic response and cause a rise in Th1 and Th2 immune responses in mice. These results suggest that ß-enolase could be used as a characterizing substance for the detection of fish allergens in the food industry as well as the preparation of drugs for allergy-related studies.

Characterising the role of enolase in a stable Small Colony Variant of Staphylococcus aureus isolated from a diabetic foot infection patient with osteomyelitis.

The switch to alternate cell types by Staphylococcus aureus creates sub-populations even within an active population, that are highly resilient, tolerant to antibiotics and lack clinical symptoms of infection. These cells present a challenge for clinical treatment where even after initial intervention has seemingly cleared the infection, these alternate cell types persist within tissue to revert and cause disease. Small colony variants (SCV) are a cell type which facilitate persistent infection but clinically isolated SCVs are often unstable in laboratory conditions. We have isolated a pair of S. aureus isolates from an individual patient with osteomyelitis presenting with heterogenous phenotypes; a stable SCV (sSCV) and a SCV that reverts upon laboratory culturing to the usual, active and non-SCV cell type. Thus we are able use this pair to investigate and compare the genetic mechanisms that underlie the clinical variatons of SCV phenotype. The switch to the sSCV phenotype was associated with frameshift mutations in the enolase eno and the histidine kinase arlS. The phenoptye of the sSCV was an impeded growth dependent on amino acid catabolism and modulated biofilm. These mutations present potentially a new molecular mechanism which confer persistence within osteomyelitis.

ARNTL2 facilitates bladder cancer progression through potentiating ENO1-mediated glycolysis in a SLC31A1-independent and -dependent manner.

BACKGROUND: Basic helix-loop-helix ARNT like 2 (ARNTL2) is a transcription factor that controls the circadian rhythm. Amounts of studies have demonstrated the carcinogenic function of ARNTL2 in human malignant tumors albeit the underlying mechanisms remain poorly understood. We aimed to study the significance of ARNTL2 in bladder cancer (BLCA). METHODS: Immunohistochemical staining, immunoblotting and the database from TCGA were used to analyze the clinical relevance of ARNTL2, enolase 1 (ENO1) and solute carrier family 31 member 1 (SLC31A1) in BLCA. The function of ARNTL2 was explored by cell proliferation assay, apoptosis, colony formation and xenografted tumorigenesis. The molecular mechanisms of ARNTL2-driving BLCA development were investigated by RT-qPCR, immunoblotting and luciferase assays. Glycolysis was checked by measuring glucose consumption and lactate production. ENO1 activity was assessed by using indicated assay kit. RESULTS: Overexpression of ARNTL2 facilitates the proliferation and tumorigenesis of BLCA cells through suppression of apoptosis and enhancement of glycolysis. Up-regulation of SLC31A1, ENO1, and enhancement of SLC31A1-mediated ENO1 activity were critical for ARNTL2-triggered glycolysis and malignant growth in BLCA cells. ARNTL2 was positively correlated with SLC31A1 and ENO1 in BLCA patients. High expression of ARNTL2, SLC31A1 or ENO1 predicted the poor prognosis of BLCA patients. Depletion of SLC31A1 and inhibition of glycolysis completely blunted the growth ability of BLCA cells. CONCLUSION: In summary, ARNTL2 facilitates the progression of BLCA via activating ENO1-mediated glycolysis in a SLC31A1-independent and -dependent manner. Inhibiting SLC31A1 and glycolysis may be an aspirational approach for the treatment of BLCA patients with overexpression of ARNTL2.

Moonlighting on the Fasciola hepatica tegument: Enolase, a glycolytic enzyme, interacts with the extracellular matrix and fibrinolytic system of the host.

Enolase is a 47 kDa enzyme that functions within the glycolysis and gluconeogenesis pathways involved in the reversible conversion of D-2-phosphoglycerate (2PGA) to phosphoenolpyruvate (PEP). However, in the context of host-pathogen interactions, enolase from different species of parasites, fungi and bacteria have been shown to contribute to adhesion processes by binding to proteins of the host extracellular matrix (ECM), such as fibronectin (FN) or laminin (LM). In addition, enolase is a plasminogen (PLG)-binding protein and induces its activation to plasmin, the main protease of the host fibrinolytic system. These secondary 'moonlighting' functions of enolase are suggested to facilitate pathogen migration through host tissues. This study aims to uncover the moonlighting role of enolase from the parasite Fasciola hepatica, shedding light on its relevance to host-parasite interactions in fasciolosis, a global zoonotic disease of increasing concern. A purified recombinant form of F. hepatica enolase (rFhENO), functioning as an active homodimeric glycolytic enzyme of ~94 kDa, was successfully obtained, fulfilling its canonical role. Immunoblotting studies on adult worm extracts showed that the enzyme is present in the tegument and the excretory/secretory products of the parasite, which supports its key role at the host-parasite interface. Confocal immunolocalisation studies of the protein in newly excysted juveniles and adult worms also localised its expression within the parasite tegument. Finally, we showed by ELISA that rFhENO can act as a parasitic adhesin by binding host LM, but not FN. rFhENO also binds PLG and enhances its conversion to plasmin in the presence of the tissue-type and urokinase-type PLG activators (t-PA and u-PA). This moonlighting adhesion-like function of the glycolytic protein enolase could contribute to the mechanisms by which F. hepatica efficiently invades and migrates within its host and encourages further research efforts that are designed to impede this function by vaccination or drug design.

In pancreatic cancer patients, chemotherapy reshapes the gene expression profile and antigen receptor repertoire of T lymphocytes and enhances their effector response to tumor-associated antigens.

Introduction: Pancreatic Ductal Adenocarcinoma (PDA) is one of the most aggressive malignancies with a 5-year survival rate of 13%. Less than 20% of patients have a resectable tumor at diagnosis due to the lack of distinctive symptoms and reliable biomarkers. PDA is resistant to chemotherapy (CT) and understanding how to gain an anti-tumor effector response following stimulation is, therefore, critical for setting up an effective immunotherapy. Methods: Proliferation, and cytokine release and TCRB repertoire of from PDA patient peripheral T lymphocytes, before and after CT, were analyzed in vitro in response to four tumor-associated antigens (TAA), namely ENO1, FUBP1, GAPDH and K2C8. Transcriptional state of PDA patient PBMC was investigated using RNA-Seq before and after CT. Results: CT increased the number of TAA recognized by T lymphocytes, which positively correlated with patient survival, and high IFN-γ production TAA-induced responses were significantly increased after CT. We found that some ENO1-stimulated T cell clonotypes from CT-treated patients were expanded or de-novo induced, and that some clonotypes were reduced or even disappeared after CT. Patients that showed a higher number of effector responses to TAA (high IFN-γ/IL-10 ratio) after CT expressed increased fatty acid-related transcriptional signature. Conversely, patients that showed a higher number of regulatory responses to TAA (low IFN-γ/IL-10 ratio) after CT significantly expressed an increased IRAK1/IL1R axis-related transcriptional signature. Conclusion: These data suggest that the expression of fatty acid or IRAK1/IL1Rrelated genes predicts T lymphocyte effector or regulatory responses to TAA in patients that undergo CT. These findings are a springboard to set up precision immunotherapies in PDA based on the TAA vaccination in combination with CT.

The molecular basis underlying T cell specificity towards citrullinated epitopes presented by HLA-DR4.

CD4+ T cells recognising citrullinated self-epitopes presented by HLA-DRB1 bearing the shared susceptibility epitope (SE) are implicated in rheumatoid arthritis (RA). However, the underlying T cell receptor (TCR) determinants of epitope specificity towards distinct citrullinated peptide antigens, including vimentin-64cit59-71 and α-enolase-15cit10-22 remain unclear. Using HLA-DR4-tetramers, we examine the T cell repertoire in HLA-DR4 transgenic mice and observe biased TRAV6 TCR gene usage across these two citrullinated epitopes which matches with TCR bias previously observed towards the fibrinogen ß-74cit69-81 epitope. Moreover, shared TRAV26-1 gene usage is evident in four α-enolase-15cit10-22 reactive T cells in three human samples. Crystal structures of mouse TRAV6+ and human TRAV26-1+ TCR-HLA-DR4 complexes presenting vimentin-64cit59-71 and α-enolase-15cit10-22, respectively, show three-way interactions between the TCR, SE, citrulline, and the basis for the biased selection of TRAV genes. Position 2 of the citrullinated epitope is a key determinant underpinning TCR specificity. Accordingly, we provide a molecular basis of TCR specificity towards citrullinated epitopes.

Isobavachalcone Exhibits Potent Antifungal Efficacy by Inhibiting Enolase Activity and Glycolysis in Candida albicans.

Invasive fungal diseases (IFDs) are becoming increasingly acknowledged as a significant concern linked to heightened rates of morbidity and mortality. Regrettably, the available antifungal therapies for managing IFDs are constrained. Emerging evidence indicates that enolase holds promise as a potential target protein for combating IFDs; however, there is currently a deficiency in antifungal medications specifically targeting enolase. This study establishes that isobavachalcone (IBC) exhibits noteworthy antifungal efficacy both in vitro and in vivo. Moreover, our study has demonstrated that IBC effectively targets Eno1 in Candida albicans (CaEno1), resulting in the suppression of the glycolytic pathway. Additionally, our research has indicated that IBC exhibits a higher affinity for CaEno1 compared to human Eno1 (hEno1), with the presence of isoprenoid in the side chain of IBC playing a crucial role in its ability to inhibit enolase activity. These findings contribute to the comprehension of antifungal approaches that target Eno1, identifying IBC as a potential inhibitor of Eno1 in human pathogenic fungi.

Effect of Silencing subolesin and enolase impairs gene expression, engorgement and reproduction in Haemaphysalis longicornis (Acari: Ixodidae) ticks.

IMPORTANCE: Haemaphysalis longicornis is an obligate blood-sucking ectoparasite that has gained attention due its role of transmitting medically and veterinary significant pathogens and it is the most common tick species in Republic of Korea. The preferred strategy for controlling ticks is a multi-antigenic vaccination. Testing the efficiency of a combination antigen is a promising method for creating a tick vaccine. OBJECTIVE: The aim of the current research was to analyze the role of subolesin and enolase in feeding and reproduction of H. longicornis by gene silencing. METHODS: In this study, we used RNA interference to silence salivary enolase and subolesin in H. longicornis. Unfed female ticks injected with double-stranded RNA targeting subolesin and enolase were attached and fed normally on the rabbit's ear. Real-time polymerase chain reaction was used to confirm the extent of knockdown. RESULTS: Ticks in the subolesin or enolase dsRNA groups showed knockdown rates of 80% and 60% respectively. Ticks in the combination dsRNA (subolesin and enolase) group showed an 80% knockdown. Knockdown of subolesin and enolase resulted in significant depletion in feeding, blood engorgement weight, attachment rate, and egg laying. Silencing of both resulted in a significant (p < 0.05) reduction in tick engorgement, egg laying, egg hatching (15%), and reproduction. CONCLUSIONS AND RELEVANCE: Our results suggest that subolesin and enolase are an exciting target for future tick control strategies.

HOXC6-mediated transcriptional activation of ENO2 promotes oral squamous cell carcinoma progression through the Warburg effect.

Oral squamous cell carcinoma (OSCC) requires an in-depth exploration of its molecular mechanisms. The Warburg effect, along with the oncogenes enolase 2 (ENO2) and homeobox C6 (HOXC6), plays a central role in cancer. However, the specific interaction between ENO2 and HOXC6 in driving the Warburg effect and OSCC progression remains poorly understood. Through differential gene expression analysis in head and neck squamous cell carcinomas using Gene Expression Profiling Interactive Analysis, we identified upregulated ENO2 in OSCC. Silencing ENO2 in OSCC cells revealed its involvement in migration, invasion, and aerobic glycolysis of OSCC cells. Further exploration of ENO2's regulatory network identified HOXC6 as a potential transcriptional regulator. Subsequently, HOXC6 was silenced in OSCC cells, and expressions of ENO2 were assessed to validate its relationship with ENO2. Chromatin Immunoprecipitation and luciferase assays were utilized to investigate the direct transcriptional activation of ENO2 by HOXC6. A rescue assay co-overexpressing ENO2 and silencing HOXC6 in OSCC cells affirmed HOXC6's role in ENO2-associated glycolysis. High ENO2 expression in OSCC was validated through quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry analyses, which correlated with poor patient survival. Functional assays demonstrated that ENO2 silencing inhibited glycolysis and attenuated the aggressiveness of OSCC cells. In vivo studies confirmed the oncogenic role of ENO2 in OSCC growth. Notably, HOXC6 exhibited a positive correlation with ENO2 expression in clinical samples. Mechanistically, HOXC6 was identified as a direct transcriptional activator of ENO2, orchestrating the Warburg effect in OSCC cells. This study reveals the intricate link between HOXC6-mediated ENO2 transcriptional activation and the Warburg effect in OSCC, offering a potential therapeutic target for treating OSCC patients.

N6-Methyladenosine enhances the translation of ENO1 to promote the progression of bladder cancer by inhibiting PCNA ubiquitination.

The mechanism underlying N6-methyladenosine (m6A) modification in bladder cancer (BC) remains elusive. We identified that the RBM15/METTL3 complex enhances m6A modification and promotes the ENO1 protein translation efficiency through its 359A site by depending on YTHDF1 in BC cells. In the tumor microenvironment, TGF-ß effectively stimulates RBM15/METTL3 expression to improve ENO1 mRNA m6A modification through the Smad2/3 pathway. Reduced ENO1 m6A levels hamper tumor proliferation both in vitro and in vivo. Mechanistically, ENO1 augments PCNA protein stability by reducing its K48-linked ubiquitination and thus prevents protein degradation through the endoplasmic reticulum-associated degradation pathway. According to the subsequent experiments, the ENO1 inhibitor significantly reduced tumor proliferation both in vitro and in vivo. Our study highlights the significance of RBM15/METTL3 complex-mediated ENO1 mRNA m6A modification in ENO1 expression. It also reveals a novel mechanism by which ENO1 promotes BC progression, thereby suggesting that ENO1 can be a therapeutic target for BC.

Molecular cloning, identification, transcriptional analysis, and silencing of enolase on the life cycle of Haemaphysalis longicornis (Acari, Ixodidae) tick.

Ticks, blood-sucking ectoparasites, spread diseases to humans and animals. Haemaphysalis longicornis is a significant vector for tick-borne diseases in medical and veterinary contexts. Identifying protective antigens in H. longicornis for an anti-tick vaccine is a key tick control strategy. Enolase, a multifunctional protein, significantly converts D-2-phosphoglycerate and phosphoenolpyruvate in glycolysis and gluconeogenesis in cell cytoplasm. This study cloned a complete open reading frame (ORF) of enolase from the H. longicornis tick and characterized its transcriptional and silencing effect. We amplified the full-length cDNA of the enolase gene using rapid amplification of cDNA ends. The complete cDNA, with an ORF of 1,297 nucleotides, encoded a 432-amino acid polypeptide. Enolase of the Jeju strain H. longicornis exhibited the highest sequence similarity with H. flava (98%), followed by Dermacentor silvarum (82%). The enolase motifs identified included N-terminal and C-terminal regions, magnesium binding sites, and several phosphorylation sites. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that enolase mRNA transcripts were expressed across all developmental stages of ticks and organs such as salivary gland and midgut. RT-PCR showed higher transcript levels in syn-ganglia, suggesting that synganglion nerves influence enolase,s role in tick salivary glands. We injected enolase double-stranded RNA into adult unfed female ticks, after which they were subsequently fed with normal unfed males until they spontaneously dropped off. RNA interference significantly (P<0.05) reduced feeding and reproduction, along with abnormalities in eggs (no embryos) and hatching. These findings suggest enolase is a promising target for future tick control strategies.

Investigation of ENO2 as a promising novel marker for the progression of colorectal cancer with microsatellite instability-high.

BACKGROUND: Microsatellite instability-high (MSI-H) has emerged as a significant biological characteristic of colorectal cancer (CRC). Studies reported that MSI-H CRC generally had a better prognosis than microsatellite stable (MSS)/microsatellite instability-low (MSI-L) CRC, but some MSI-H CRC patients exhibited distinctive molecular characteristics and experienced a less favorable prognosis. In this study, our objective was to explore the metabolic transcript-related subtypes of MSI-H CRC and identify a biomarker for predicting survival outcomes. METHODS: Single-cell RNA sequencing (scRNA-seq) data of MSI-H CRC patients were obtained from the Gene Expression Omnibus (GEO) database. By utilizing the copy number variation (CNV) score, a malignant cell subpopulation was identified at the single-cell level. The metabolic landscape of various cell types was examined using metabolic pathway gene sets. Subsequently, functional experiments were conducted to investigate the biological significance of the hub gene in MSI-H CRC. Finally, the predictive potential of the hub gene was assessed using a nomogram. RESULTS: This study revealed a malignant tumor cell subpopulation from the single-cell RNA sequencing (scRNA-seq) data. MSI-H CRC was clustered into two subtypes based on the expression profiles of metabolism-related genes, and ENO2 was identified as a hub gene. Functional experiments with ENO2 knockdown and overexpression demonstrated its role in promoting CRC cell migration, invasion, glycolysis, and epithelial-mesenchymal transition (EMT) in vitro. High expression of ENO2 in MSI-H CRC patients was associated with worse clinical outcomes, including increased tumor invasion depth (p = 0.007) and greater likelihood of perineural invasion (p = 0.015). Furthermore, the nomogram and calibration curves based on ENO2 showed potential prognosis predictive performance. CONCLUSION: Our findings suggest that ENO2 serves as a novel prognostic biomarker and is associated with the progression of MSI-H CRC.

Correlations of Expression Levels of Lung Cancer Marker Gene Eno2 and Genes of Carcinogenesis and Apoptosis in the Hypothalamus of Mice with Depression-Like Behavior.

We experimentally demonstrated that chronic social stress during the development of a depression-like state enhances lung metastasis and modifies the expression of many carcinogenesis- and apoptosis-related genes in the hypothalamus of mice, including genes involved in lung cancer pathogenesis in humans. Analysis of the expression of genes encoding the major clinical markers of lung cancer in the hypothalamus of mice with depression-like behavior revealed increased expression of the Eno2 gene encoding neuron-specific enolase, a blood marker of lung cancer progression in humans. It was shown that the expression of this gene in the hypothalamus correlated with the expression of many carcinogenesis- and apoptosis-related genes. The discovered phenomenon may have a fundamental significance and requires further studies.

3-Hydroxytanshinone Inhibits the Activity of Hypoxia-Inducible Factor 1-α by Interfering with the Function of α-Enolase in the Glycolytic Pathway.

Tumor cells in hypoxic conditions control cancer metabolism and angiogenesis by expressing HIF-1α. Tanshinone is a traditional Chinese medicine that has been shown to possess antitumor properties and exerts a therapeutic impact on angiogenesis. However, the precise molecular mechanism responsible for the antitumor activity of 3-Hydroxytanshinone (3-HT), a type of tanshinone, has not been fully understood. Therefore, our study aimed to investigate the mechanism by which 3-HT regulates the expression of HIF-1α. Our findings demonstrate that 3-HT inhibits HIF-1α activity and expression under hypoxic conditions. Additionally, 3-HT inhibits hypoxia-induced angiogenesis by suppressing the expression of VEGF. Moreover, 3-HT was found to directly bind to α-enolase, an enzyme associated with glycolysis, resulting in the suppression of its activity. This inhibition of α-enolase activity by 3-HT leads to the blockade of the glycolytic pathway and a decrease in glycolysis products, ultimately altering HIF1-α expression. Furthermore, 3-HT negatively regulates the expression of HIF-1α by altering the phosphorylation of AMP-activated protein kinase (AMPK). Our study's findings elucidate the mechanism by which 3-HT regulates HIF-1α through the inhibition of the glycolytic enzyme α-enolase and the phosphorylation of AMPK. These results suggest that 3-HT holds promise as a potential therapeutic agent for hypoxia-related angiogenesis and tumorigenesis.

Circular RNA circESYT2 serves as a microRNA-665 sponge to promote the progression of hepatocellular carcinoma through ENO2.

Circular RNAs (circRNAs) have emerged as crucial regulators in tumor progression, yet their specific role in hepatocellular carcinoma (HCC) remains largely uncharacterized. In this study, we utilized high-transcriptome sequencing to identify the upregulation of circESYT2 (hsa_circ_002142) in HCC tissues. Functional experiments carried out in vivo and in vitro revealed that circESYT2 played a significant role in maintaining the growth and metastatic behaviors of HCC. Through integrative analysis, we identified enolase 2 (ENO2) as a potential target regulated by circESYT2 through the competitive endogenous RNA sponge mechanism. Additional gain- or loss-of-function experiments indicated that overexpression of circESYT2 led to a tumor-promoting effect, which could be reversed by transfection of microRNA-665 (miR-665) mimic or ENO2 knockdown in HCC cells. Furthermore, the direct interaction between miR-665 and circESYT2 and between miR-665 and ENO2 was confirmed using RNA immunoprecipitation, FISH, RNA pull-down, and dual-luciferase reporter assays, highlighting the involvement of the circESYT2/miR-665/ENO2 axis in promoting HCC progression. These findings shed light on the molecular characteristics of circESYT2 in HCC tissues and suggest its potential as a biomarker or therapeutic target for HCC treatment.

PROTEIN L-ISOASPARTYL METHYLTRANSFERASE protects enolase dysfunction by repairing isoaspartyl-induced damage and is positively implicated in agronomically important seed traits.

The protein-repairing enzyme (PRE) PROTEIN L-ISOASPARTYL METHYLTRANSFERASE (PIMT) influences seed vigor by repairing isoaspartyl-mediated protein damage in seeds. However, PIMTs function in other seed traits, and the mechanisms by which PIMT affects such seed traits are still poorly understood. Herein, through molecular, biochemical, and genetic studies using overexpression and RNAi lines in Oryza sativa and Arabidopsis thaliana, we demonstrate that PIMT not only affects seed vigor but also affects seed size and weight by modulating enolase (ENO) activity. We have identified ENO2, a glycolytic enzyme, as a PIMT interacting protein through Y2H cDNA library screening, and this interaction was further validated by BiFC and co-immunoprecipitation assay. We show that mutation or suppression of ENO2 expression results in reduced seed vigor, seed size, and weight. We also proved that ENO2 undergoes isoAsp modification that affects its activity in both in vivo and in vitro conditions. Further, using MS/MS analyses, amino acid residues that undergo isoAsp modification in ENO2 were identified. We also demonstrate that PIMT repairs such isoAsp modification in ENO2 protein, protecting its vital cellular functions during seed maturation and storage, and plays a vital role in regulating seed size, weight, and seed vigor. Taken together, our study identified ENO2 as a novel substrate of PIMT, and both ENO2 and PIMT in turn implicate in agronomically important seed traits.

Analysis of the relationship between MYCN gene and serum NSE and urinary VMA levels and neuroblastoma pathological features and prognosis.

The purpose of this study was to explore the relationship between the MYCN gene, serum neuron-specific enolase (NSE), urinary vanillylmandelic acid (VMA) levels, and neuroblastoma pathological features and prognosis. Ninety-four children with neuroblastoma treated in the hospital were selected to compare the differences in MYCN gene amplification, serum NSE, and urinary VMA levels in children with different clinicopathological features and prognoses. The proportion of children with MYCN gene copy number ≥10 in INSS stage 3-4 was higher than that of children with INSS stage 1-2 (P < 0.05); the proportion of children with MYCN gene copy number ≥10 in high-risk children in the COG risk stratification was higher than that of children with intermediate and low risk (P < 0.05); the serum NSE of children aged >12 months higher than that of children aged ≤12 months (P < 0.05); serum NSE of children with tumors >500 cm3 higher than that of children with tumors ≤500 cm3 (P < 0.05); serum NSE and urinary VMA of children with INSS staging of stages 3-4 were higher than that of children with stages 1 to 2 (P < 0.05); serum NSE and urinary VMA in children with lymph node metastasis were higher than that of children without lymph node metastasis (P < 0.05); serum NSE of children with MYCN gene copy number ≥10 was higher than that of children without lymph node metastasis (P < 0.05); the proportion of children with MYCN gene copy number ≥10 who died, and the percentages of serum NSE and urinary VMA were higher than those of the surviving children (P < 0.05). MYCN gene amplification and serum NSE and urinary VMA levels were related to the age, tumor size, INSS stage, COG stage, lymph node metastasis, and prognosis of the children with neuroblastoma.