Oncogenic TRIB2 interacts with and regulates PKM2 to promote aerobic glycolysis and lung cancer cell procession

Enhancing m6A modification in the motor cortex facilitates corticospinal tract remodeling after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202506000-00026/figure1/v/2024-08-05T133530Z/r/image-tiff Spinal cord injury typically causes corticospinal tract disruption. Although the disrupted corticospinal tract can self-regenerate to a certain degree, the underlying mechanism of this process is still unclear. N6-methyladenosine (m6A) modifications are the most common form of epigenetic regulation at the RNA level and play an essential role in biological processes. However, whether m6A modifications participate in corticospinal tract regeneration after spinal cord injury remains unknown. We found that expression of methyltransferase 14 protein (METTL14) in the locomotor cortex was high after spinal cord injury and accompanied by elevated m6A levels. Knockdown of Mettl14 in the locomotor cortex was not favorable for corticospinal tract regeneration and neurological recovery after spinal cord injury. Through bioinformatics analysis and methylated RNA immunoprecipitation-quantitative polymerase chain reaction, we found that METTL14 regulated Trib2 expression in an m6A-regulated manner, thereby activating the mitogen-activated protein kinase pathway and promoting corticospinal tract regeneration. Finally, we administered syringin, a stabilizer of METTL14, using molecular docking. Results confirmed that syringin can promote corticospinal tract regeneration and facilitate neurological recovery by stabilizing METTL14. Findings from this study reveal that m6A modification is involved in the regulation of corticospinal tract regeneration after spinal cord injury.

KAT3B Promotes the Glycolysis and Malignant Progression of Lung Cancer by Mediating the Succinylation Modification of PKM2

Lysine succinyltransferase KAT3B plays a critical role in the progression of various cancers by modulating key metabolic pathways, including glycolysis. However, the function and underlying mechanism of KAT3B in glycolysis and lung cancer (LC) progression remain to be further studied. We determined mRNA expression levels of lysine succinyl-modifying enzymes through qRT-PCR. Protein expression and succinylation status of glycolysis-related proteins PKM2, LDHA, and ENO1 were analyzed via Western blot. Co-immunoprecipitation and immunofluorescence microscopy were employed to verify the interaction between KAT3B and PKM2. Bioinformatics analysis predicted succinylation sites on PKM2, which were subsequently validated through site-directed mutagenesis. The effects of KAT3B and PKM2 on LC cell malignancy and glycolysis were evaluated using CCK-8, transwell migration, glucose uptake, lactate production, ECAR, and OCR assays. A xenograft tumor model was utilized to assess the impact of KAT3B on LC tumor growth. We confirmed the augmentation of KAT3B in LC, which also was correlated with advanced TNM stages and elevated T stages of LC patients. Conversely, KAT3B knockdown suppressed the growth, metastasis, and glycolytic activity of LC cells in vitro, while also inhibiting tumor growth in vivo. KAT3B mediated succinylation at PKM2 K298, and the suppression of LC cell malignancy and glycolysis upon KAT3B downregulation was largely reversed by upregulation of PKM2. The KAT3B/PKM2 axis may be a novel target for LC therapy.

Interactions of tumor necrosis factor receptor-associated factor 4 and pyruvate kinase muscle isoform 2 promote malignant behavior and aerobic glycolysis in colorectal cancer cells

Objective

Colorectal cancer (CRC) is a malignant tumor of the digestive system, and the main causes of death are metastasis and recurrence. Tumor necrosis factor receptor-associated factor 4 (TRAF4) is associated with the development of various tumors, but its role in CRC development is limited, especially glycolysis. Therefore, TRAF4's role in the regulation of cell malignant behavior and glycolysis and its specific mechanism were explored in CRC.

Material and Methods

The TRAF4 or pyruvate kinase muscle isoform 2 (PKM2) gene expression was inhibited or promoted by short hairpin ribonucleic acid (sh- RNA) or overexpression (oe) plasmids in Lovo cells. Transfection efficiency was detected by Western blot and real-time quantitative polymerase chain reaction. Cell growth and colony formation were assessed using 5-ethynyl-2'-deoxyuridine and clone formation assays, respectively, and cell migration and invasion ability were observed by scratch healing and Transwell assay. Glucose uptake and lactate production were measured with a kit and used in evaluating the glycolysis capacities of the cells. The levels of TRAF4, PKM2, and glycolytic-related and wingless-type (Wnt)/beta (β)-catenin pathway-related proteins were detected by Western blot, and co-immunoprecipitation (Co-IP) verified TRAF4 and PKM2 interaction in CRC cells.

Results

TRAF4 expression increased in CRC cell lines (P < 0.05, P < 0.001, P < 0.0001). After sh-TRAF4, oeTRAF4, or oe-PKM2 transfection, TRAF4 or PKM2 expression levels in the Lovo cells decreased or increased (P < 0.05, P < 0.01, P < 0.001, and P < 0.0001). TRAF4 knockdown inhibited cell malignant behavior, glucose uptake, lactate production, and glucose transporter type 1 (GLUT1), hexokinase 2 (HK2), PKM2, and lactate dehydrogenase A (LDHA) protein expression levels in CRC cells (P < 0.01, P < 0.001, P < 0.0001). Co-IP experiment showed that TRAF4 was bound to PKM2. PKM2 protein level decreased after TRAF4 knockdown (P < 0.0001), and PKM2 protein expression increased when TRAF4 was overexpressed (P < 0.001). PKM2 overexpression offset the effect of TRAF4 knockdown on cell malignant behavior and aerobic glycolysis (P < 0.05, P < 0.01, P < 0.001, and P < 0.0001). Moreover, Wnt/β-catenin pathway proteins were inhibited after TRAF4 knockdown and were restored by PKM2 overexpression (P < 0.01 and P < 0.0001). Notably, the effects of TRAF4 or PKM2 overexpression on cell malignant behavior, glucose uptake, lactate production, and GLUT1, PKM2, HK2, and LDHA protein expression levels were partially offset by the Wnt/β-catenin signaling suppressor XAV939 (P < 0.05, P < 0.01, P < 0.001, and P < 0.0001).

Conclusion

TRAF4 and PKM2 are associated with CRC development. TRAF4 binds to PKM2 and promotes CRC malignant behavior and glycolysis through the Wnt/β-catenin signaling pathway.

The role of tribbles homolog 2 in cell proliferation

Tribbles homolog 2 (TRIB2), a pseudoserine/threonine kinase, is a member of the TRIB family. TRIB2 primarily regulates cell proliferation through its scaffold or adaptor effect on promoting the degradation of target proteins by E3 ligase-dependent ubiquitination and regulating mitogen-activated protein kinase (MAPK) and protein kinase B (AKT) signaling pathways. TRIB2 is not only involved in the physiological proliferation of cells (granulosa cells, myoblasts, naive T cells, and thymocytes) during normal development but also in the pathological proliferation of vascular smooth muscle cells and a variety of cancer cells (lung cancer cells, liver cancer cells, leukemia cells, pancreatic cancer cells, gastric cancer cells, prostate cancer cells, thyroid cancer cells, cervical cancer cells, melanoma cells, colorectal cancer cells, ovarian cancer cells and osteosarcoma cells) under disease conditions. Its expression level and functional role predominantly hinge on the specific tissue and cell type it targets. This review elucidates the specific mechanisms of TRIB2 in physiological and pathological cell proliferation from the perspective of different kinds of cells.

Amino Acid and Glucose Fermentation Maintain ATP Content in Mouse and Human Malignant Glioma Cells

Energy is necessary for tumor cell viability and growth. Aerobic glucose-driven lactic acid fermentation is a common metabolic phenotype seen in most cancers including malignant gliomas. This metabolic phenotype is linked to abnormalities in mitochondrial structure and function. A luciferin-luciferase bioluminescence ATP assay was used to measure the influence of amino acids, glucose, and oxygen on ATP content and viability in mouse (VM-M3 and CT-2A) and human (U-87MG) glioma cells that differed in cell biology, genetic background, and species origin. Oxygen consumption was measured using the Resipher system. Extracellular lactate and succinate were measured as end products of the glycolysis and glutaminolysis pathways, respectively. The results showed that: (1) glutamine was a source of ATP content irrespective of oxygen. No other amino acid could replace glutamine in sustaining ATP content and viability; (2) ATP content persisted in the absence of glucose and under hypoxia, ruling out substantial contribution through either glycolysis or oxidative phosphorylation (OxPhos) under these conditions; (3) Mitochondrial complex IV inhibition showed that oxygen consumption was not an accurate measure for ATP production through OxPhos. The glutaminase inhibitor, 6-diazo-5-oxo-L-norleucine (DON), reduced ATP content and succinate export in cells grown in glutamine. The data suggests that mitochondrial substrate level phosphorylation in the glutamine-driven glutaminolysis pathway contributes to ATP content in these glioma cells. A new model is presented highlighting the synergistic interaction between the high-throughput glycolysis and glutaminolysis pathways that drive malignant glioma growth and maintain ATP content through the aerobic fermentation of both glucose and glutamine.

UBR5 metabolically reprograms nasopharyngeal carcinoma cells to promote glycolysis and M2 polarization via SPLUNC1 signaling

Nasopharyngeal carcinoma (NPC) is the most common cancer originating in nasopharynx. Metabolic reprogramming plays a critical role in tumor progression. Exploring mechanisms underlying metabolic reprogramming contributes to deeper understanding of NPC pathogenesis. Here, we found downregulation of RORA and SPLUNC1 in NPC, and RORA downregulation indicates poor prognosis. RORA binds to SPLUNC1 promoter to induce its transcription, and RORA overexpression inhibits cell proliferation and glycolysis by directly upregulating SPLUNC1. UBR5 inhibits RORA via promoting RORA ubiquitination and degradation, and UBR5 silencing represses proliferation and glycolysis in NPC. Additionally, METTL14, which is highly expressed in NPC, facilitates UBR5 mRNA stability by promoting its m6A modification through IGF2BP2. UBR5/RORA/SPLUNC1 axis facilitates M2 polarization by activating the GPR132 signaling. UBR5 silencing inhibits tumor growth, glycolysis and M2 polarization through RORA/SPLUNC1 signaling in mice. In conclusion, UBR5 promotes proliferation, glycolysis and M2 polarization by metabolically reprograming NPC cells through suppression of the RORA/SPLUNC1 signaling.

Reprogramming of glucose metabolism: The hallmark of malignant transformation and target for advanced diagnostics and treatments

Reprogramming of cancer metabolism has become increasingly concerned over the last decade, particularly the reprogramming of glucose metabolism, also known as the "Warburg effect". The reprogramming of glucose metabolism is considered a novel hallmark of human cancers. A growing number of studies have shown that reprogramming of glucose metabolism can regulate many biological processes of cancers, including carcinogenesis, progression, metastasis, and drug resistance. In this review, we summarize the major biological functions, clinical significance, potential targets and signaling pathways of glucose metabolic reprogramming in human cancers. Moreover, the applications of natural products and small molecule inhibitors targeting glucose metabolic reprogramming are analyzed, some clinical agents targeting glucose metabolic reprogramming and trial statuses are summarized, as well as the pros and cons of targeting glucose metabolic reprogramming for cancer therapy are analyzed. Overall, the reprogramming of glucose metabolism plays an important role in the prediction, prevention, diagnosis and treatment of human cancers. Glucose metabolic reprogramming-related targets have great potential to serve as biomarkers for improving individual outcomes and prognosis in cancer patients. The clinical innovations related to targeting the reprogramming of glucose metabolism will be a hotspot for cancer therapy research in the future. We suggest that more high-quality clinical trials with more abundant drug formulations and toxicology experiments would be beneficial for the development and clinical application of drugs targeting reprogramming of glucose metabolism.This review will provide the researchers with the broader perspective and comprehensive understanding about the important significance of glucose metabolic reprogramming in human cancers.

m6A-methylated KCTD21-AS1 regulates macrophage phagocytosis through CD47 and cell autophagy through TIPR

Blocking immune checkpoint CD47/SIRPα is a useful strategy to engineer macrophages for cancer immunotherapy. However, the roles of CD47-related noncoding RNA in regulating macrophage phagocytosis for lung cancer therapy remain unclear. This study aims to investigate the effects of long noncoding RNA (lncRNA) on the phagocytosis of macrophage via CD47 and the proliferation of non-small cell lung cancer (NSCLC) via TIPRL. Our results demonstrate that lncRNA KCTD21-AS1 increases in NSCLC tissues and is associated with poor survival of patients. KCTD21-AS1 and its m6A modification by Mettl14 promote NSCLC cell proliferation. miR-519d-5p gain suppresses the proliferation and metastasis of NSCLC cells by regulating CD47 and TIPRL. Through ceRNA with miR-519d-5p, KCTD21-AS1 regulates the expression of CD47 and TIPRL, which further regulates macrophage phagocytosis and cancer cell autophagy. Low miR-519d-5p in patients with NSCLC corresponds with poor survival. High TIPRL or CD47 levels in patients with NSCLC corresponds with poor survival. In conclusion, we demonstrate that KCTD21-AS1 and its m6A modification promote NSCLC cell proliferation, whereas miR-519d-5p inhibits this process by regulating CD47 and TIPRL expression, which further affects macrophage phagocytosis and cell autophagy. This study provides a strategy through miR-519-5p gain or KCTD21-AS1 depletion for NSCLC therapy by regulating CD47 and TIPRL.

ERK/PKM2 Is Mediated in the Warburg Effect and Cell Proliferation in Arsenic-Induced Human L-02 Hepatocytes

This study aimed to investigate the potential role of pyruvate kinase M2 (PKM2) and extracellular regulated protein kinase (ERK) in arsenic-induced cell proliferation. L-02 cells were treated with 0.2 and 0.4 μmol/L As3+, glycolysis inhibitor (2-deoxy-D-glucose,2-DG), ERK inhibitor [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)-butadiene, U0126] or transfected with PKM2 plasmid. Cell viability, proliferation, lactate acid production, and glucose intake capacity were determined by CCK-8 assay, EdU assay, lactic acid kit and 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose (2-NBDG) uptake kit, respectively. Also, levels of PKM2, phospho-PKM2S37, glucose transporter protein 1 (GLUT1), lactate dehydrogenase A (LDHA), ERK, and phospho-ERK were detected using Western blot and the subcellular localization of PKM2 in L-02 cells was detected by immunocytochemistry (ICC). Treatment with 0.2 and 0.4 μmol/L As3+ for 48 h increased the viability and proliferation of L-02 cells, the proportion of 2-NBDG+ cell and lactic acid in the culture medium, and GLUT1, LDHA, PKM2, phospho-PKM2S37, and phospho-ERK levels and PKM2 in nucleus. Compared with the 0.2 μmol/L As3+ treatment group, the lactic acid in the culture medium, cell proliferation and cell viability, and the expression of GLUT1 and LDHA were reduced in the group co-treated with siRNA-PKM2 and arsenic or in the group co-treated with U0126. Moreover, the arsenic-increased phospho-PKM2S37/PKM2 was decreased by U0126. Therefore, ERK/PKM2 plays a key role in the Warburg effect and proliferation of L-02 cells induced by arsenic, and also might be involved in arsenic-induced upregulation of GLUT1 and LDHA. This study provides a theoretical basis for further elucidating the carcinogenic mechanism of arsenic.

Dimethyl Bisphenolate Ameliorates Carbon Tetrachloride-Induced Liver Injury by Regulating Oxidative Stress-Related Genes

Liver disease accounts for millions of deaths per year all over the world due to complications from cirrhosis and liver injury. In this study, a novel compound, dimethyl bisphenolate (DMB), was synthesized to investigate its role in ameliorating carbon tetrachloride (CCl4)-induced liver injury through the regulation of oxidative stress-related genes. The structure of DMB was confirmed based on its hydrogen spectrum and mass spectrometry. DMB significantly reduced the high levels of ALT, AST, DBIL, TBIL, ALP, and LDH in a dose-dependent manner in the sera of CCl4-treated rats. The protective effects of DMB on biochemical indicators were similar to those of silymarin. The ROS fluorescence intensity increased in CCl4-treated cells but significantly weakened in DMB-treated cells compared with the controls. DMB significantly increased the content of oxidative stress-related GSH, Nrf2, and GCLC dose-dependently but reduced MDA levels in CCl4-treated cells or the liver tissues of CCl4-treated rats. Moreover, DMB treatment decreased the expression levels of P53 and Bax but increased those of Bcl2. In summary, DMB demonstrated protective effects on CCl4-induced liver injury by regulating oxidative stress-related genes.

Genome-wide expression profiling reveals novel biomarkers in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most aggressive and frequent malignancy detected among women worldwide. The pathophysiology of OC should, therefore be better understood to identify diagnostic, prognostic, and predictive novel biomarkers necessary for early detection, management, and prognostication. In this study, we aimed to investigate transcriptomic landscape and biomarker through RNA-seq data analysis. Further analysis by Protein Protein network identified top 10 Differentially Expressed Genes (DEGs). KEGG pathway enrichment analysis revealed the significant enrichment of DEGs in basal cell carcinoma, cell cycle and FoxO signalling pathway. The RNA-seq results of 10 DEGs were validated by QRT-PCR and TCGA database. Correlation studies were also performed between gene expression and clinical characteristics followed by survival analysis. Finally, 8 DEGs (CDKN1A, BCL6, CDC45, WNT2, TLR5, AQP5) including two novel DEGs (CSN1S1 and NKILA) were identified showing significant correlations with EOC characteristics. These may serve as interesting biomarkers and novel treatment targets and warrant further investigation into the functional outcome of EOC.

Characterization and Prognosis of Biological Microenvironment in Lung Adenocarcinoma through a Disulfidptosis-Related lncRNAs Signature

Background

The role of disulfidptosis-related lncRNAs remains unclear in lung adenocarcinoma.

Methods

Analysis in R software was conducted using different R packages, which are based on the public data from The Cancer Genome Atlas (TCGA) database. The transwell assay was used to evaluate the invasion and migration abilities of lung cancer cells.

Results

In our study, we identified 1401 lncRNAs significantly correlated with disulfidptosis-related genes (|Cor| > 0.3 and P < 0.05). Then, we constructed a prognosis model consisting of 11 disulfidptosis-related lncRNAs, including AL133445.2, AL442125.1, AC091132.2, AC090948.1, AC020765.2, CASC8, AL606834.1, LINC00707, OGFRP1, U91328.1, and GASAL1. This prognosis model has satisfactory prediction performance. Also, the risk score and clinical information were combined to develop a nomogram. Analyses of biological enrichment and immune-related data were used to identify underlying differences between patients at high-risk and low-risk groups. Moreover, we noticed that the immunotherapy nonresponders have higher risk scores. Meanwhile, patients at a high risk responded more strongly to docetaxel, paclitaxel, and vinblastine. Furthermore, further analysis of the model lncRNA OGFRP1 was conducted, including clinical, immune infiltration, biological enrichment analysis, and a transwell assay. We discovered that by inhibiting OGFRP1, the invasion and migration abilities of lung cancer cells could be remarkably hindered.

Conclusion

The results of our study can provide directions for future research in the relevant areas. Moreover, the prognosis signature we identified has the potential for clinical application.

The role of tribbles homolog 2 in vascular smooth muscle cell proliferation

Tribbles homolog 2 (TRIB2) functions as an adapter protein that regulates signal transductions involved in a variety of cellular functions, including tumorigenesis. However, the role of TRIB2 in the proliferation of vascular smooth muscle cells (VSMCs) and the underlying expression mechanisms remain unclear. The present study investigated the role of TRIB2 in VSMC proliferation and revealed that TRIB2 expression increases following vascular injury and platelet-derived growth factor (PDGF)-BB-stimulated VSMCs. We found that pretreatment with diphenyleneiodonium (a nicotinamide adenine dinucleotide phosphate oxidase inhibitor), U0126 (an inhibitor of mitogen-activated protein kinase kinase 1 [MEK1]), or siRNA targeting the gene encoding early growth response 1 (EGR-1) significantly inhibits PDGF-BB-induced TRIB2 expression in VSMCs. Furthermore, TRIB2 knockdown significantly inhibits PDGF-BB-induced proliferation of VSMCs but does not affect the phosphorylation of AKT. However, phosphorylation of ERK1 and expression of proliferating cell nuclear antibody are significantly suppressed in VSMCs by PDGF-BB stimulation. Thus, PDGF-BB-induced TRIB2 expression is mediated by ROS/ERK/EGR-1 pathways and plays a critical role in VSMC proliferation via modulation of ERK activity. We propose TRIB2 as a promising therapeutic target for the prevention of neointima formation and vascular disease.

Metabolic management of microenvironment acidity in glioblastoma

Glioblastoma (GBM), similar to most cancers, is dependent on fermentation metabolism for the synthesis of biomass and energy (ATP) regardless of the cellular or genetic heterogeneity seen within the tumor. The transition from respiration to fermentation arises from the documented defects in the number, the structure, and the function of mitochondria and mitochondrial-associated membranes in GBM tissue. Glucose and glutamine are the major fermentable fuels that drive GBM growth. The major waste products of GBM cell fermentation (lactic acid, glutamic acid, and succinic acid) will acidify the microenvironment and are largely responsible for drug resistance, enhanced invasion, immunosuppression, and metastasis. Besides surgical debulking, therapies used for GBM management (radiation, chemotherapy, and steroids) enhance microenvironment acidification and, although often providing a time-limited disease control, will thus favor tumor recurrence and complications. The simultaneous restriction of glucose and glutamine, while elevating non-fermentable, anti-inflammatory ketone bodies, can help restore the pH balance of the microenvironment while, at the same time, providing a non-toxic therapeutic strategy for killing most of the neoplastic cells.