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Breast cancer (BC) is a prevalent malignant tumor in women, and its incidence has been steadily increasing in recent years. Compared with other types of cancer, it has the highest mortality and morbidity rates in women. So, it is crucial to investigate the underlying mechanisms of BC development and identify specific therapeutic targets. Pyruvate kinase M2 (PKM2), an important metabolic enzyme in glycolysis, has been found to be highly expressed in BC. It can also move to the nucleus and interact with various transcription factors and proteins, including hypoxia-inducible factor-1a (HIF-1a), signal transducer and activator of transcription 3 (STAT3), b-catenin, cellular-myelocytomatosis oncogene (c-Myc), nuclear factor kappa-light-chain enhancer of activated B cells (NF-kB), and mammalian sterile 20-like kinase 1 (MST1). This interaction leads to non-metabolic functions that control the cell cycle, proliferation, apoptosis, migration, invasion, angiogenesis, and tumor microenvironment in BC. This review provides an overview of the latest advancements in understanding the interactions between PKM2 and different transcription factors and proteins that influence the initiation and progression of BC. It also examined how natural drugs and noncoding RNAs affect various biological processes in BC cells through the regulation of the non-metabolic enzyme functions of PKM2. The findings provide valuable insights for improving the prognosis and developing targeted therapies for BC in the coming years. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the deadly malignant tumors that directly leads to the death of nearly one million people worldwide every year, causing a serious burden on society. In the presence of sufficient oxygen, HCC cells rapidly generate energy through aerobic glycolysis, which promotes tumor cell proliferation, immune evasion, metastasis, angiogenesis, and drug resistance. Pyruvate kinase M2 (PKM2) is a key rate‐limiting enzyme in glycolysis. In recent years, studies have found that PKM2 not only exerts pyruvate kinase activity in the process of glucose metabolism, but also exerts protein kinase activity in non‐metabolic pathways to affect tumor cell processes, and its activity is flexibly regulated by various posttranslational modifications such as acetylation, phosphorylation, lactylation, ubiquitination, SUMOylation, and so forth. This review summarizes the role of posttranslational modifications of PKM2‐related sites in the development of HCC. Summary: Hepatocellular carcinoma (HCC) is one of the deadly malignant tumors.Even in the case of sufficient oxygen, HCC cells rapidly generate energy through aerobic glycolysis.Pyruvate kinase M2 (PKM2) is a key rate‐limiting enzyme in glycolysis.Recent studies have found that the posttranslational modification of PKM2 flexibly regulates its pyruvate kinase activity and protein kinase activity, thus affecting the important physiological functions of cells.This review summarizes the role of posttranslational modifications of PKM2‐related sites in the development of HCC.It has been found that posttranslational modifications of PKM2‐related sites mostly promote the occurrence, metastasis and drug resistance of HCC, often suggesting poor prognosis. [ABSTRACT FROM AUTHOR]

Cancer is a global health challenge, despite significant advancements in research. Addressing this issue, we report the design, synthesis and biological evaluation of pyrimidinyl indoles as potential antineoplastic agents. Pyrimidinyl indoles interact with pyruvate kinase isoform M2 (PKM2), which is commonly overexpressed in oral, lung, breast and colorectal cancers. In silico studies indicated that these molecules are having affinity towards PKM2 and targeting key residues such as Phe26, Leu27, Tyr390, Gln393, Leu394 and Glu397 at the interfacial active site region between the two chains of PKM2. Thereafter compounds were designed, synthesized and characterized using nuclear magnetic resonance (NMR), infrared spectroscopy (IR) and mass spectrometry (MS). This was followed by in vitro screening using cell lines and enzyme‐coupled assays. One of the designed PKM2 inhibitor demonstrated potent anticancer activity against MCF‐7 (Breast Cancer) cells while sparing normal MCF‐10 A breast cells. Molecular dynamics (MD) simulation studies showed that the developed inhibitor stabilized the PKM2 active site over a 100 ns simulation. [ABSTRACT FROM AUTHOR]

Nonalcoholic steatohepatitis (NASH) may soon become the leading cause of end-stage liver disease worldwide with limited treatment options. Liver fibrosis, which is driven by chronic inflammation and hepatic stellate cell (HSC) activation, critically determines morbidity and mortality in patients with NASH. Pyruvate kinase M2 (PKM2) is involved in immune activation and inflammatory liver diseases; however, its role and therapeutic potential in NASH-related fibrosis remain largely unexplored. Bioinformatics screening and analysis of human and murine NASH livers indicated that PKM2 was upregulated in nonparenchymal cells (NPCs), especially macrophages, in the livers of patients with fibrotic NASH. Macrophage-specific PKM2 knockout (PKM2FL/FLLysM-Cre) significantly ameliorated hepatic inflammation and fibrosis severity in three distinct NASH models induced by a methionine- and choline-deficient (MCD) diet, a high-fat high-cholesterol (HFHC) diet, and a western diet plus weekly carbon tetrachloride injection (WD/CCl4). Single-cell transcriptomic analysis indicated that deletion of PKM2 in macrophages reduced profibrotic Ly6Chigh macrophage infiltration. Mechanistically, PKM2-dependent glycolysis promoted NLR family pyrin domain containing 3 (NLRP3) activation in proinflammatory macrophages, which induced HSC activation and fibrogenesis. A pharmacological PKM2 agonist efficiently attenuated the profibrotic crosstalk between macrophages and HSCs in vitro and in vivo. Translationally, ablation of PKM2 in NPCs by cholesterol-conjugated heteroduplex oligonucleotides, a novel oligonucleotide drug that preferentially accumulates in the liver, dose-dependently reversed NASH-related fibrosis without causing observable hepatotoxicity. The present study highlights the pivotal role of macrophage PKM2 in advancing NASH fibrogenesis. Thus, therapeutic modulation of PKM2 in a macrophage-specific or liver-specific manner may serve as a novel strategy to combat NASH-related fibrosis.

Abstract Phosphoglycerate kinase 1 (PGK1) and pyruvate kinase M2 (PKM2) have been identified as the postmortem meat quality biomarkers. However, the precise molecular mechanism through which they affect and regulate the development of meat quality remains unclear. In this work, the high‐ and low‐activity groups (n = 10) were selected from 60 lamb muscles at 24 h postmortem based on the activity levels of PGK1 and PKM2. The metabolomic, proteomic, and transcriptomic analyses combined with deeply integrated multi‐omics analysis were used to elucidate the mechanisms by which PGK1 and PKM2 characterize meat quality. The results indicated that glycolysis played a crucial role in regulating PGK1 and PKM2 activity at the metabolome, proteome, and transcriptome levels. In glycolysis pathway, we identified several key components closely related to PGK1 and PKM2 activity, including differential metabolites (adenosine triphosphate, adenosine diphosphate, glucose‐6‐phosphate, nicotinamide adenine dinucleotide phosphate, fructose‐6‐phosphate, dihydroxyacetone phosphate, 3‐phosphoglycerate, NAD+ nicotinamide adenine dinucleotide, lactate, and pyruvate), different abundance proteins (lactate dehydrogenase B and fructose bisphosphate aldolase B), and differentially expressed genes (hexokinase and fructose‐1,6‐bisphosphatase 1). It was concluded that PGK1 and PKM2 may affect the formation of meat quality by regulating these critical substrates. Additionally, PGK1 and PKM2 could also affect the tricarboxylic acid cycle, oxidative phosphorylation, and muscle contraction in postmortem and then influence meat quality. This integrative omics study offers valuable insight into unraveling the molecular mechanisms underlying postmortem meat quality development.

Background: A desired target for cancer therapy is a cancer-specific metabolism which is associated with innate or acquired therapeutic resistance, malignancies, and aggressive cancer growth. Nevertheless, these cells utilize manifold metabolic routes to prolong their mass explosion. Human hexokinase 2 (HK2), phosphofructokinase, muscle (PFKM), pyruvate kinase M2 (PKM2), and lactate dehydrogenase A (LDHA) are fundamental signature players of cancer glycolysis playing a role in cancer cell regulation. Reflecting their metabolic roles may be possible with a better grasp of the metabolism transition in the early onset and spread of cancer. This study was designed to assess the serum protein levels of HK2, PFKM, PKM2, and LDHA in women with breast carcinoma and its correlation with phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) pathway. Methods: In the current research, case–control investigation was undertaken with breast cancer women (n = 30) and compatible healthy women (n = 30) visiting Justice K. S. Hegde Charitable Hospital, Deralakatte, Mangaluru, who were selected on the basis of inclusion and exclusion criteria. Baseline characteristics for the study population were marked down. The HK2, PFKM, PKM2, and LDHA levels within serum were estimated by means of sandwich enzyme-linked immunosorbent assay. Results: We observed a difference that was significant among the two groups with regard to age and postmenopausal status and also a difference in first-degree family history. The levels of PKM2 and key glycolytic enzymes in serum varied between the case and control groups. There was a positive correlation that was observed in breast carcinoma subjects with glycolytic proteins and signaling pathway (PI3K/Akt/mTOR). Conclusions: Nevertheless, assured processes that persuade the target enzymes remain vague and require further in-depth exploration. Overall, discovering anticancer therapeutics that target glycolytic enzymes involved in glucose metabolism remains a dilemma.

It is well established that pyruvate kinase M2 (PKM2) activity contributes to metabolic reprogramming in various cancers, including colorectal cancer (CRC). Estrogen or 17β‐estradiol (E2) signaling is also known to modulate glycolysis markers in cancer cells. However, whether the inhibition of PKM2 combined with E2 treatment could adversely affect glucose metabolism in CRC cells remains to be investigated. First, we confirmed the metabolic plasticity of CRC cells under varying environmental conditions. Next, we identified glycolysis markers that were upregulated in CRC patients and assessed in vitro mRNA levels following E2 treatment. We found that PKM2 expression, which is highly upregulated in CRC clinical samples, is not altered by E2 treatment in CRC cells. In this study, glucose uptake, generation of reactive oxygen species (ROS), lactate production, cell viability, and apoptosis were evaluated in CRC cells following E2 treatment, PKM2 silencing, or a combination of both. Compared to individual treatments, combination therapy resulted in a significant reduction in cell viability and enhanced apoptosis. Glucose uptake and ROS production were markedly reduced in PKM2‐silenced E2‐treated cells. The data presented here suggest that E2 signaling combined with PKM2 inhibition cumulatively targets glucose metabolism in a manner that negatively impacts CRC cell growth. These findings hold promise for novel therapeutic strategies targeting altered metabolic pathways in CRC. Highlights: Colorectal cancer (CRC) cells exhibit a versatile metabolic profile that is responsive to changes in the tumor microenvironment.Estrogen (E2) signaling modulates glycolysis and reduces CRC cell growth and survival.Pyruvate kinase M2 (PKM2) inhibition also modulates glycolysis and reduces CRC cell growth.Combining E2 treatment with PKM2 inhibition precipitates significant cumulative antitumor effects in CRC cells. [ABSTRACT FROM AUTHOR]

AIM: To clarify the effect of macrophage PKM2 deficiency on mucosal repair in ulcerative colitis (UC). METHODS: The gene expression and metabolic profiles in UC patients were first analyzed based on the following databases: PXD001608, GSE193677, and GSE214695. Using the macrophage-specific PKM2 elimination mice (PKM2AMAC), the functions of PKM2 in dextran sulfate sodium (DSS)-induced UC were clarified in vivo by analyzing the body weight, disease activity index (DAI) scores, HE staining, immunohistochemical staining, and expression of mucosal barrier markers. The impact of PKM2 on macrophage polarization was also investigated by flow cytometry, RNA sequencing and RT-qPCR in mouse bone marrow-derived macrophages (BMDMs) and THP-1 cells in vitro. RESULTS: Bioinformatic analysis suggested that the intestinal tissues of UC patients preferred glycolysis. The expression of PKM was parallel to the severity of UC in patients, and the expression of PKM2, but not PKM1, was elevated in macrophages of UC mice. In the DSS-induced UC mice, macrophage-specific PKM2 elimination significantly alleviates the body weight loss, diarrhea, rectal bleeding, colonic shorten, as well as decreased DAI scores and mucosal tissue damage. The BMDMs derived from the PKM2ΔMAC mice preferred the M2 polarization upon LPS or IL-4 stimulation to that derived from the wild-type mice, as indicated by the F4/80+ CD45+ CD86+ and F4/80+ CD45+ CD206+ population, as well as the expression of Ocln, F11r and Tjp-1. The RNA sequencing results indicated significant gene differential expression in PKM2 knockout mouse macrophages, which was enriched in biological processes such as leukocyte migration, tissue remodeling, and cytokine interactions. Macrophage PKM2 deficiency promoted the expression of mucosal repair factors (118, Cxcl1, Ptgs2 and Wnt6, which was further validated in PKM2 knockout THP-1 cells. CONCLUSION: The PKM2 deficiency in macrophages benifits the mucosal repair in UC status via facilitating the wound-healing macrophage polarization. [ABSTRACT FROM AUTHOR]

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Pyruvate kinase M2 (PKM2), a rate limiting enzyme in glycolysis, is a cellular regulator that has received extensive attention and regards as a metabolic regulator of cellular metabolism and energy. Kidney is a highly metabolically active organ, and glycolysis is the important energy resource for kidney. The accumulated evidences indicates that the enzymatic activity of PKM2 is disturbed in kidney disease progression and treatment, especially diabetic kidney disease and acute kidney injury. Modulating PKM2 post-translational modification determines its enzymatic activity and nuclear translocation that serves as an important interventional approach to regulate PKM2. Emerging evidences show that PKM2 and its post-translational modification participate in kidney disease progression and treatment through modulating metabolism regulation, podocyte injury, fibroblast activation and proliferation, macrophage polarization, and T cell regulation. Interestingly, PKM2 activators (TEPP-46, DASA-58, mitapivat, and TP1454) and PKM2 inhibitors (shikonin, alkannin, compound 3k and compound 3h) have exhibited potential therapeutic property in kidney disease, which indicates the pleiotropic effects of PKM2 in kidney. In the future, the deep investigation of PKM2 pleiotropic effects in kidney is urgently needed to determine the therapeutic effect of PKM2 activator/inhibitor to benefit patients. The information in this review highlights that PKM2 functions as a potential biomarker and therapeutic target for kidney diseases. [ABSTRACT FROM AUTHOR]

Induction of cancer cell death is an established treatment strategy, but chemotherapy drug-mediated apoptosis can be evaded by many tumors. Pyroptosis is a type of inflammatory programmed cell death (PCD) that is important for organism immunity. Tubeimoside-I (TBMS1) is a plant-derived component that exhibits antitumor activity. However, it is unclear how TBMS1 induces pyroptosis to inhibit colorectal cancer (CRC). In this study, we demonstrated that TBMS1 is able to induce pyroptosis in murine CRC cells and releases pro-inflammatory cytokines. Mechanistically, we found that TBMS1 inhibits CRC cell proliferation and migration and induces pyroptosis by activating caspase-3 and cleaving gasdermin E (GSDME) through the inhibition of PKM2. In the animal experiments, TBMS1 attenuated the weight of solid tumors, increased the proportion of CD8+ cytotoxic T cells, and reduced the content of M2-type macrophages in the spleen of tumor-bearing mice. Furthermore, TBMS1 inhibited M2-type polarization by blocking STAT6 pathway activation in RAW 264.7 cells. To sum up, our findings suggest that TBMS1 triggers pyroptosis in CRC by acting on the PKM2/caspase-3/GSDME signaling pathway. Additionally, it modulates the antitumor immune response in CRC murine models. This study provides a promising basis for the potential use of TBMS1 in treating CRC. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is a prevalent malignant tumor in women, and its incidence has been steadily increasing in recent years. Compared with other types of cancer, it has the highest mortality and morbidity rates in women. So, it is crucial to investigate the underlying mechanisms of BC development and identify specific therapeutic targets. Pyruvate kinase M2 (PKM2), an important metabolic enzyme in glycolysis, has been found to be highly expressed in BC. It can also move to the nucleus and interact with various transcription factors and proteins, including hypoxia-inducible factor-1α (HIF-1α), signal transducer and activator of transcription 3 (STAT3), β-catenin, cellular-myelocytomatosis oncogene (c-Myc), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), and mammalian sterile 20-like kinase 1 (MST1). This interaction leads to non-metabolic functions that control the cell cycle, proliferation, apoptosis, migration, invasion, angiogenesis, and tumor microenvironment in BC. This review provides an overview of the latest advancements in understanding the interactions between PKM2 and different transcription factors and proteins that influence the initiation and progression of BC. It also examined how natural drugs and noncoding RNAs affect various biological processes in BC cells through the regulation of the non-metabolic enzyme functions of PKM2. The findings provide valuable insights for improving the prognosis and developing targeted therapies for BC in the coming years.

Reactive astrocytes play critical roles in the occurrence of various neurological diseases such as multiple sclerosis. Activation of astrocytes is often accompanied by a glycolysis-dominant metabolic switch. However, the role and molecular mechanism of metabolic reprogramming in activation of astrocytes have not been clarified. Here, we found that PKM2, a rate-limiting enzyme of glycolysis, displayed nuclear translocation in astrocytes of EAE (experimental autoimmune encephalomyelitis) mice, an animal model of multiple sclerosis. Prevention of PKM2 nuclear import by DASA-58 significantly reduced the activation of mice primary astrocytes, which was observed by decreased proliferation, glycolysis and secretion of inflammatory cytokines. Most importantly, we identified the ubiquitination-mediated regulation of PKM2 nuclear import by ubiquitin ligase TRIM21. TRIM21 interacted with PKM2, promoted its nuclear translocation and stimulated its nuclear activity to phosphorylate STAT3, NF-κB and interact with c-myc. Further single-cell RNA sequencing and immunofluorescence staining demonstrated that TRIM21 expression was upregulated in astrocytes of EAE. TRIM21 overexpressing in mice primary astrocytes enhanced PKM2-dependent glycolysis and proliferation, which could be reversed by DASA-58. Moreover, intracerebroventricular injection of a lentiviral vector to knockdown TRIM21 in astrocytes or intraperitoneal injection of TEPP-46, which inhibit the nuclear translocation of PKM2, effectively decreased disease severity, CNS inflammation and demyelination in EAE. Collectively, our study provides novel insights into the pathological function of nuclear glycolytic enzyme PKM2 and ubiquitination-mediated regulatory mechanism that are involved in astrocyte activation. Targeting this axis may be a potential therapeutic strategy for the treatment of astrocyte-involved neurological disease.

Abstract Objective Glioma, a malignant primary brain tumor, is notorious for its high incidence rate. However, the clinical application of temozolomide (TMZ) as a treatment option for glioma is often limited due to resistance, which has been linked to hypoxic glioma cell-released exosomes. In light of this, the present study aimed to investigate the role of exosomal pyruvate kinase M2 (PKM2) in glioma cells that exhibit resistance to TMZ. Methods Sensitive and TMZ-resistant glioma cells were subjected to either a normoxic or hypoxic environment, and the growth patterns and enzymatic activity of glycolysis enzymes were subsequently measured. From these cells, exosomal PKM2 was isolated and the subsequent effect on TMZ resistance was examined and characterized, with a particular focus on understanding the relevant mechanisms. Furthermore, the intercellular communication between hypoxic resistant cells and tumor-associated macrophages (TAMs) via exosomal PKM2 was also assessed. Results The adverse impact of hypoxic microenvironments on TMZ resistance in glioma cells was identified and characterized. Among the three glycolysis enzymes that were examined, PKM2 was found to be a critical mediator in hypoxia-triggered TMZ resistance. Upregulation of PKM2 was found to exacerbate the hypoxia-mediated TMZ resistance. Exosomal PKM2 were identified and isolated from hypoxic TMZ-resistant glioma cells, and were found to be responsible for transmitting TMZ resistance to sensitive glioma cells. The exosomal PKM2 also contributed towards mitigating TMZ-induced apoptosis in sensitive glioma cells, while also causing intracellular ROS accumulation. Additionally, hypoxic resistant cells also released exosomal PKM2, which facilitated TMZ resistance in tumor-associated macrophages. Conclusion In the hypoxic microenvironment, glioma cells become resistant to TMZ due to the delivery of PKM2 by exosomes. Targeted modulation of exosomal PKM2 may be a promising strategy for overcoming TMZ resistance in glioma.

Abstract Background Patients with hypopharyngeal carcinoma (HPC) have a poor prognosis mainly because of lymphatic metastasis. This research aimed to determine the PKM2 role in lymphatic metastasis in HPC and the underlying molecular mechanism contributing to this phenomenon. Methods PKM2 in HPC was studied for its expression and its likelihood of overall survival using TCGA dataset. Western blotting, qRT-PCR, and IHC were employed to confirm PKM2 expression. Methods including gain- and loss-of-function were used to examine the PKM2 role in HPC metastasis in vitro and in vivo. In vitro and in vivo studies also confirmed lymphatic metastasis’s mechanism. Results Prominent PKM2 overexpression was seen in patients with lymphatic metastasis of HPC, and there was an inherent relationship between a high PKM2 level and poor prognosis. In vitro research showed that knocking down PKM2 decreased tumor cell invasion, migration, and proliferation while promoting apoptosis and inhibiting epithelial-mesenchymal transition, but overexpressing PKM2 had the reverse effect. Animal studies suggested that PKM2 may facilitate tumor development and lymphatic metastasis. Conclusions Our findings suggest that PKM2 may be a tumor’s promoter gene of lymphatic metastasis, which may promote lymphatic metastasis of HPC by regulating epithelial-mesenchymal transition. PKM2 may be a biomarker of metastatic potential, ultimately providing a basis for exploring new therapeutic targets.

Purpose: To describe the clinical, laboratory and multimodal imaging findings in paraneoplastic autoimmune retinopathy (p-AIR) associated with anti-pyruvate kinase M2 antibody (anti-PKM2) and occult pancreatic adenocarcinoma. Observations: A 70 year old male with blurred vision, nyctalopia and concurrent difficulty with glucose control had retinal vascular attenuation and diffuse punctate pigment clumping in both eyes. Multimodal imaging demonstrated corresponding stippled hypofluorescence on fluorescein angiography, stippled hyperautofluorescence and a hyperautoflourescent macular ring with fundus autofluorescence, and focal hyperreflectivity at the level of the RPE-Bruch's membrane complex with diffuse loss of outer retinal layers on ocular coherence tomography. In addition, diffuse ganglion cell loss and severe visual field constriction were present. Genetic testing for retinitis pigmentosa was normal. Screening for anti-retinal antibodies was positive for only anti-PKM2. Systemic evaluation revealed previously undiagnosed adenocarcinoma of the pancreas. Conclusions and importance: Anti-PKM2 in the setting of autoimmune retinopathy may be associated with occult pancreatic cancer. The diagnosis of pAIR should be considered and systemic investigation for occult malignancy initiated even in the absence of more commonly associated anti-retinal antibodies.

Background: Breast cancer (BC) is the most commonly diagnosed cancer in women. Treatment approaches that differ between estrogen-positive (ER+) and triple-negative BC cells (TNBCs) and may subsequently affect cancer biomarkers, such as H19 and telomerase, are an emanating delight in BC research. For instance, all-trans-Retinoic acid (ATRA) could represent a potent regulator of these oncogenes, regulating microRNAs, mostly let-7a microRNA (miR-let-7a), which targets the glycolysis pathway, mainly pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) enzymes. Here, we investigated the potential role of ATRA in H19, telomerase, miR-let-7a, and glycolytic enzymes modulation in ER + and TNBC cells. Methods: MCF-7 and MDA-MB-231 cells were treated with 5 µM ATRA and/or 100 nM fulvestrant. Then, ATRA-treated or control MCF-7 cells were transfected with either H19 or hTERT siRNA. Afterward, ATRA-treated or untreated MDA-MB-231 cells were transfected with estrogen receptor alpha ER(α) or beta ER(β) expression plasmids. RNA expression was evaluated by RT‒qPCR, and proteins were assessed by Western blot. PKM2 activity was measured using an NADH/LDH coupled enzymatic assay, and telomerase activity was evaluated with a quantitative telomeric repeat amplification protocol assay. Student's t-test or one-way ANOVA was used to analyze data from replicates. Results: Our results showed that MCF-7 cells were more responsive to ATRA than MDA-MB-231 cells. In MCF-7 cells, ATRA and/or fulvestrant decreased ER(α), H19, telomerase, PKM2, and LDHA, whereas ER(β) and miR-let-7a increased. H19 or hTERT knockdown with or without ATRA treatment showed similar results to those obtained after ATRA treatment, and a potential interconnection between H19 and hTERT was found. However, in MDA-MB-231 cells, RNA expression of the aforementioned genes was modulated after ATRA and/or fulvestrant, with no significant effect on protein and activity levels. Overexpression of ER(α) or ER(β) in MDA-MB-231 cells induced telomerase activity, PKM2 and LDHA expression, in which ATRA treatment combined with plasmid transfection decreased glycolytic enzyme expression. Conclusions: To the best of our knowledge, our study is the first to elucidate a new potential interaction between the estrogen receptor and glycolytic enzymes in ER + BC cells through miR-let-7a. [ABSTRACT FROM AUTHOR]

Objective: To discuss the effects of different doses of ganoderic acid A (GAA) on the biological activities, glycolysis, and the expression of rate-limiting enzymes of non-small cell lung cancer (NSCLC) PC9 cells, and to clarify the mechanism. Methods: The NSCLC PC9 cells were cultured in vitro and divided into blank control group, low dose (25 µmol·L-1) of GAA group, medium dose (50 µmol·L-1) of GAA group, and high dose (100 µmol·L-1) of GAA group. The methylthiazolydiphenyltetrazolium (MTT) assay was used to detect the survival rates of the PC9 cells in various groups; Transwell chamber assay was used to detect the number of migration cells of the PC9 cells in various groups; the glucose uptakes of the PC9 cells in various groups were detected by glucose assay kit; the levels of ATP in the PC9 cells in various groups were detected by ATP assay kit; the levels of lactic acid in the PC9 cells in various groups were detected by lactate assay kit; the expression levels of hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2) mRNA in the PC9 cells in various groups were detected by real-time fluorescence quantitative PCR (RT-qPCR) method; the expression levels of HK2 and PKM2 proteins in the PC9 cells in various groups were detected by Western blotting method. Results: The MTT assay results showed that, at 24, 48, and 72 h of culture, compared with blank control group, the survival rates of the cells in medium and high doses of GAA groups were significantly decreased (P<0. 05). At 72 h of culture, compared with low dose of GAA group, the survival rate of the cells in high dose of GAA group was significantly decreased (P<0. 05). The Transwell chamber assay results showed that compared with blank control group, the numbers of migration cells in medium and high doses of GAA groups were significantly decreased (P<0. 05); compared with low doses of GAA group, the number of migration cells in high dose of GAA group was significantly decreased (P<0. 05). Compared with blank control group, the glucose uptakes and levels of lactic acid in the cells in medium and high dose of GAA groups were significantly decreased (P<0. 05), and the level of ATP in the cells in high dose of GAA group was significantly decreased (P<0. 05). The RT-qPCR results showed that compared with blank control group, the expression levels of HK2 and PKM2 mRNA in the cells in medium and high doses of GAA groups were significantly decreased (P<0. 05). The Western blotting results showed that compared with blank control group, the expression levels of HK2 and PKM2 proteins in the cells in medium and high doses of GAA groups were significantly decreased (P<0. 05). Conclusion: Medium and high doses of GAA can inhibit the biological activities of proliferation and migration of the PC9 cells, reduce the glycolysis, and its mechanism may be related to the inhibition of the expressions of the key rate-limiting enzymes HK2 and PKM2. [ABSTRACT FROM AUTHOR]

Pyruvate kinase M2 (PKM2), a subtype of pyruvate kinase (PK), has been shown to play an important role in the development of cancer. It regulates the last step of glycolytic pathway. PKM2 has both pyruvate kinase and protein kinase activity, and the conversion of these two functions of PKM2 depends on the mutual change of dimer and tetramer. The dimerization of PKM2 can promote the proliferation and growth of tumor cells, so inhibiting the dimerization of PKM2 is essential to curing cancer. The aggregation of PKM2 is regulated by both endogenous and exogenous cofactors as well as post-translational modification (PTM). Although there are many studies on the different aggregation of PKM2 in the process of tumor development, there are few summaries in recent years. In this review, we first introduce the role of PKM2 in various biological processes of tumor growth. Then, we summarize the aggregation regulation mechanism of PKM2 by various endogenous cofactors such as Fructose-1, 6-diphosphate (FBP), various amino acids, and post-translational modification (PTMs). Finally, the related inhibitors and agonists of PKM2 are summarized to provide reference for regulating PKM2 aggregation in the treatment of cancer in the future. [ABSTRACT FROM AUTHOR]

Objective: Glioma, a malignant primary brain tumor, is notorious for its high incidence rate. However, the clinical application of temozolomide (TMZ) as a treatment option for glioma is often limited due to resistance, which has been linked to hypoxic glioma cell-released exosomes. In light of this, the present study aimed to investigate the role of exosomal pyruvate kinase M2 (PKM2) in glioma cells that exhibit resistance to TMZ. Methods: Sensitive and TMZ-resistant glioma cells were subjected to either a normoxic or hypoxic environment, and the growth patterns and enzymatic activity of glycolysis enzymes were subsequently measured. From these cells, exosomal PKM2 was isolated and the subsequent effect on TMZ resistance was examined and characterized, with a particular focus on understanding the relevant mechanisms. Furthermore, the intercellular communication between hypoxic resistant cells and tumor-associated macrophages (TAMs) via exosomal PKM2 was also assessed. Results: The adverse impact of hypoxic microenvironments on TMZ resistance in glioma cells was identified and characterized. Among the three glycolysis enzymes that were examined, PKM2 was found to be a critical mediator in hypoxia-triggered TMZ resistance. Upregulation of PKM2 was found to exacerbate the hypoxia-mediated TMZ resistance. Exosomal PKM2 were identified and isolated from hypoxic TMZ-resistant glioma cells, and were found to be responsible for transmitting TMZ resistance to sensitive glioma cells. The exosomal PKM2 also contributed towards mitigating TMZ-induced apoptosis in sensitive glioma cells, while also causing intracellular ROS accumulation. Additionally, hypoxic resistant cells also released exosomal PKM2, which facilitated TMZ resistance in tumor-associated macrophages. Conclusion: In the hypoxic microenvironment, glioma cells become resistant to TMZ due to the delivery of PKM2 by exosomes. Targeted modulation of exosomal PKM2 may be a promising strategy for overcoming TMZ resistance in glioma. [ABSTRACT FROM AUTHOR]

Background: A desired target for cancer therapy is a cancer‑specific metabolism which is associated with innate or acquired therapeutic resistance, malignancies, and aggressive cancer growth. Nevertheless, these cells utilize manifold metabolic routes to prolong their mass explosion. Human hexokinase 2 (HK2), phosphofructokinase, muscle (PFKM), pyruvate kinase M2 (PKM2), and lactate dehydrogenase A(LDHA) are fundamental signature players of cancer glycolysis playing a role in cancer cell regulation. Reflecting their metabolic roles may be possible with a better grasp of the metabolism transition in the early onset and spread of cancer. This study was designed to assess the serum protein levels of HK2, PFKM, PKM2, and LDHA in women with breast carcinoma and its correlation with phosphatidylinositol-3-kinase (PI3K)/ Akt and the mammalian target of rapamycin (mTOR) pathway. Methods: In the current research, case–control investigation was undertaken with breast cancer women (n = 30) and compatible healthy women (n = 30) visiting Justice K. S. Hegde Charitable Hospital, Deralakatte, Mangaluru, who were selected on the basis of inclusion and exclusion criteria. Baseline characteristics for the study population were marked down. The HK2, PFKM, PKM2, and LDHA levels within serum were estimated by means of sandwich enzyme-linked immunosorbent assay. Results: We observed a difference that was significant among the two groups with regard to age and postmenopausal status and also a difference in first‑degree family history. The levels of PKM2 and key glycolytic enzymes in serum varied between the case and control groups. There was a positive correlation that was observed in breast carcinoma subjects with glycolytic proteins and signaling pathway (PI3K/Akt/mTOR). Conclusions: Nevertheless, assured processes that persuade the target enzymes remain vague and require further in-depth exploration. Overall, discovering anticancer therapeutics that target glycolytic enzymes involved in glucose metabolism remains a dilemma. [ABSTRACT FROM AUTHOR]

Background: Patients with hypopharyngeal carcinoma (HPC) have a poor prognosis mainly because of lymphatic metastasis. This research aimed to determine the PKM2 role in lymphatic metastasis in HPC and the underlying molecular mechanism contributing to this phenomenon. Methods: PKM2 in HPC was studied for its expression and its likelihood of overall survival using TCGA dataset. Western blotting, qRT-PCR, and IHC were employed to confirm PKM2 expression. Methods including gain- and loss-of-function were used to examine the PKM2 role in HPC metastasis in vitro and in vivo. In vitro and in vivo studies also confirmed lymphatic metastasis's mechanism. Results: Prominent PKM2 overexpression was seen in patients with lymphatic metastasis of HPC, and there was an inherent relationship between a high PKM2 level and poor prognosis. In vitro research showed that knocking down PKM2 decreased tumor cell invasion, migration, and proliferation while promoting apoptosis and inhibiting epithelial-mesenchymal transition, but overexpressing PKM2 had the reverse effect. Animal studies suggested that PKM2 may facilitate tumor development and lymphatic metastasis. Conclusions: Our findings suggest that PKM2 may be a tumor's promoter gene of lymphatic metastasis, which may promote lymphatic metastasis of HPC by regulating epithelial-mesenchymal transition. PKM2 may be a biomarker of metastatic potential, ultimately providing a basis for exploring new therapeutic targets. [ABSTRACT FROM AUTHOR]

Viruses exploit the host cell's energy metabolism system to support their replication. Mitochondria, known as the powerhouse of the cell, play a critical role in regulating cell survival and virus replication. Our prior research indicated that the classical swine fever virus (CSFV) alters mitochondrial dynamics and triggers glycolytic metabolic reprogramming. However, the role and mechanism of PKM2, a key regulatory enzyme of glycolytic metabolism, in CSFV replication remain unclear. In this study, we discovered that CSFV enhances PKM2 expression and utilizes PKM2 to inhibit pyruvate production. Using an affinity purification coupled mass spectrometry system, we successfully identified PKM as a novel interaction partner of the CSFV non-structural protein NS4A. Furthermore, we validated the interaction between PKM2 and both CSFV NS4A and NS5A through co-immunoprecipitation and confocal analysis. PKM2 was found to promote the expression of both NS4A and NS5A. Moreover, we observed that PKM2 induces mitophagy by activating the AMPK-mTOR signaling pathway, thereby facilitating CSFV proliferation. In summary, our data reveal a novel mechanism whereby PKM2, a metabolic enzyme, promotes CSFV proliferation by inducing mitophagy. These findings offer a new avenue for developing antiviral strategies. [ABSTRACT FROM AUTHOR]

Pyruvate kinase M2 (PKM2) is a key enzyme of glycolysis, which is highly expressed in many tumor cells, and has emerged as an important player in tumor progression and metastasis. However, the functional roles of PKM2 in tumor metastasis remain elusive. Here we showed that PKM2 promoted prostate cancer metastasis via extracellular-regulated protein kinase (ERK)--cyclooxygenase (COX-2) signaling. Based on public databases, we found that PKM2 expression was upregulated in prostate cancer and positively associated with tumor metastasis. Further analysis showed that PKM2 promoted prostate cancer cell migration/invasion and epithelial--mesenchymal transition (EMT) through upregulation of COX-2. Mechanistically, PKM2 interacted with ERK1/2 and regulated its phosphorylation, leading to phosphorylation of transcription factor c-Jun, downstream of ERK1/2, to activate COX-2 transcription by IP and ChIP assay, while inhibition of COX-2 significantly reversed the promotion effect of PKM2 on tumor metastasis in vivo. Taken together, our results suggest that a novel of PKM2--ERK1/2--c-Jun--COX-2 axis is a potential target in controlling prostate cancer metastasis. [ABSTRACT FROM AUTHOR]

Retinal ischemia plays a vital role in vision-threatening retinal ischemic disorders, such as diabetic retinopathy, age-related macular degeneration, glaucoma, etc. The aim of this study was to investigate the effects of S-allyl L-cysteine (SAC) and its associated therapeutic mechanism. Oxidative stress was induced by administration of 500 μM H2O2 for 24 h; SAC demonstrated a dose-dependent neuroprotective effect with significant cell viability effects at 100 μM, and it concurrently downregulated angiogenesis factor PKM2 and inflammatory biomarker MCP-1. In a Wistar rat model of high intraocular pressure (HIOP)-induced retinal ischemia and reperfusion (I/R), post-administration of 100 μM SAC counteracted the ischemic-associated reduction of ERG b-wave amplitude and fluorogold-labeled RGC reduction. This study supports that SAC could protect against retinal ischemia through its anti-oxidative, anti-angiogenic, anti-inflammatory, and neuroprotective properties. [ABSTRACT FROM AUTHOR]

Glyoxalase I (GLO I), a major enzyme involved in the detoxification of the anaerobic glycolytic byproduct methylglyoxal, is highly expressed in various tumors, and is regarded as a promising target for cancer therapy. We recently reported that piceatannol potently inhibits human GLO I and induces the death of GLO I‐dependent cancer cells. Pyruvate kinase M2 (PKM2) is also a potential therapeutic target for cancer treatment, so we evaluated the combined anticancer efficacy of piceatannol plus low‐dose shikonin, a potent and specific plant‐derived PKM2 inhibitor, in two GLO I‐dependent cancer cell lines, HL‐60 human myeloid leukemia cells and NCI‐H522 human non‐small‐cell lung cancer cells. Combined treatment with piceatannol and low‐dose shikonin for 48 h synergistically reduced cell viability, enhanced apoptosis rate, and increased extracellular methylglyoxal accumulation compared to single‐agent treatment, but did not alter PKM1, PKM2, or GLO I protein expression. Taken together, these results indicate that concomitant use of low‐dose shikonin potentiates piceatannol‐induced apoptosis of GLO I‐dependent cancer cells by augmenting methylglyoxal accumulation. [ABSTRACT FROM AUTHOR]

Although some cohort studies have indicated a close association between diabetes and HCC, the underlying mechanism about the contribution of diabetes to HCC progression remains largely unknown. In the study, we applied a novel HCC model in SD rat with diabetes and a series of high glucose-stimulated cell experiments to explore the effect of a high glucose environment on HCC metastasis and its relevant mechanism. Our results uncovered a novel regulatory mechanism by which nuclear translocation of metabolic enzyme PKM2 mediated high glucose-promoted HCC metastasis. Specifically, high glucose-increased PKM2 nuclear translocation downregulates chemerin expression through the redox protein TRX1, and then strengthens immunosuppressive environment to promote HCC metastasis. To the best of our knowledge, this is the first report to elucidate the great contribution of a high glucose environment to HCC metastasis from a new perspective of enhancing the immunosuppressive microenvironment. Simultaneously, this work also highlights a previously unidentified non-metabolic role of PKM2 and opens a novel avenue for cross research and intervention for individuals with HCC and comorbid diabetes.

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease worldwide. Numerous evidence has demonstrated that metabolic reprogramming serves as a hallmark associated with an elevated risk of NAFLD progression. Selenoprotein W (SelW) is an extensively expressed hepatic selenoprotein that plays a crucial role in antioxidant function. Here, we first demonstrated that SelW is a significantly distinct factor in the liver tissue of NAFLD patients through the Gene Expression Omnibus (GEO) database. Additionally, loss of SelW alleviated hepatic steatosis induced by a high-fat diet (HFD), and was accompanied by the regulation of metabolic and inflammatory pathways as verified by transcriptomic analysis. Moreover, co-immunoprecipitation (CO-IP), liquid chromatography-tandem mass spectrometry (LC-MS), laser scanning confocal microscopy (LSCM) and molecular docking analysis were subsequently implemented to identify Pyruvate Kinase M2 (PKM2) as a potential interacting protein of SelW. Meanwhile, SelW modulated PKM2 translocation into the nucleus to trigger transactivation of the HIF-1α, in further mediating mitochondrial apoptosis, eventually resulting in mitochondrial damage, ROS excessive production and mtDNA leakage. Additionally, mito-ROS accumulation induced the activation of the NLRP3 inflammasome-mediated pyroptosis, thereby facilitating extracellular leakage of mtDNA. The escaped mtDNA then evokes the cGAS-STING signaling pathway in macrophage, thus inducing a shift in macrophage phenotype. Together, our results suggest SelW promotes hepatocyte apoptosis and pyroptosis by regulating metabolic reprogramming to activate cGAS/STING signaling of macrophages, thereby exacerbating the progression of NAFLD.

Objective To investigate the effects of microRNA-21 (miR-21) on proliferation, apoptosis and aerobic clycolysis of pancreatic cancer cells and its possible mechanism. Methods Human pancreatic cancer cell SW1990 and normal pancreatic duct epithelial cell HPDE were taken as research objects. SW1990 cells were transfected and divided into miR-NC group (transfected with miR-NC) and miR-21-minic group (transfected with miR-21-minic). MTT and clone formation assay were used to detect cell proliferation ability. Flow cytometry was used to detect cell apoptosis. RT-qPCR was used to detect the mRNA expression levels of miR-21 and pyruvate kinase M2 (PKM2) in cells. Western blot was used to detect PKM2 protein level. The luciferase reporter assay was used to detect the targeting relationship between miR-21 and PKM2. Results The expression level of miR-21 in SW1990 cells was higher than that in HPDE cells (0.79±0.02 vs 0.23±0.02, t =34.290, P＜0.01), while the expression levels of PKM2 protein (0.41±0.03) and mRNA (0.62±0.02) in SW1990 cells were lower than those in HPDE cells (0.95±0.02, 1.13±0.03, t =25.940, 24.500, P＜0.01). At 72 and 96 hours, the cell proliferation ability and number of clones cell in the miR-21-minic group were significantly higher than those in the miR-NC group, while the number of apoptotic cells was lower than that in the miR-NC group (P＜0.05). The glucose consumption, and the content of lactate, hexokinase (HK) and lactate dehydrogenase (LDH) in miR-21-mimic group were significantly higher than those in miR-NC group ( t =5.992, 21.340, 5.643, 4.008, P＜0.05). The level of PKM2 protein in the miR-21 mic group was lower than that in the miR-NC group ( t =10.070, P＜0.01). There were a certain number of complementary base pairs between miR-21 and WT-3′ UTR-PKM2, and the cell luciferase activity of miR-21-minic+WT-PKM2 group was lower than that of the transfected miR-NC+WT-PKM2 group ( t =15.680, P＜0.01). Conclusion The overexpression of miR-21 in pancreatic cancer cells may promote the proliferation, aerobic glycolysis, and inhibit apoptosis of pancreatic cancer cells. The mechanism may be related to targeting PKM2.

Abstract Background Glycolysis under normoxic conditions, known as the Warburg effect, confers a selective advantage for the survival and proliferation of many tumors. In this study, we investigated the role of estrogen-related receptor gamma (ESRRG) in metabolic reprogramming in esophageal squamous cell carcinoma (ESCC). Methods Bioinformatics analysis indicated that ESRRG expression was decreased in ESCC tissue and associated with poor clinical outcomes. We also examined the effects of altered ESRRG expression on the proliferation and metabolic reprogramming of ESCC cells. We explored the impact of ESRRG on Pyruvate kinase M2 (PKM2) expression and malignant behavior in ESCC. Results Our study revealed the inhibitory effects of ESRRG on the growth, tumorigenesis, and glycolysis activity of ESCC cells, which were mediated by the downregulation of PKM2 expression. We further demonstrated that ESRRG directly interacts with the PKM2 promoter to inhibit its activity in ESCC. Notably, the ESRRG-specific agonist, DY131, inhibited ESCC cell proliferation and glycolysis activity by modulating genes in the glycolysis pathway. Moreover, we verified that DY131 exhibits enhanced activity as an immune checkpoint inhibitor, considering the significance of the ESRRG-PKM2 axis in the lactate regulation of ESCC cells. Conclusion Our findings provide novel insights into the role of ESRRG-PKM2 signaling in regulating ESCC cell metabolism and immune checkpoint regulation. Additionally, we suggest that DY131 holds promise as a promising therapeutic agent for ESCC treatment.

Pyruvate kinase M (PKM) 2 was described to interact with the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and suppress its activity. To further investigate the physiological importance of the PKM2:IP3R interaction, we developed and characterized HeLa PKM2 knockout (KO) cells. In the HeLa PKM2 KO cells, the release of Ca2+ to the cytosol appears to be more sensitive to low agonist concentrations than in HeLa wild-type (WT) cells. However, upon an identical IP3-induced Ca2+ release, Ca2+ uptake in the mitochondria is decreased in HeLa PKM2 KO cells, which may be explained by the smaller number of contact sites between the ER and the mitochondria. Furthermore, in HeLa PKM2 KO cells, mitochondria are more numerous, though they are smaller and less branched and have a hyperpolarized membrane potential. TAT-D5SD, a cell-permeable peptide representing a sequence derived from IP3R1 that can disrupt the PKM2:IP3R interaction, induces Ca2+ release into the cytosol and Ca2+ uptake into mitochondria in both HeLa WT and PKM2 KO cells. Moreover, TAT-D5SD induced apoptosis in HeLa WT and PKM2 KO cells but not in HeLa cells completely devoid of IP3Rs. These results indicate that PKM2 separately regulates cytosolic and mitochondrial Ca2+ handling and that the cytotoxic effect of TAT-D5SD depends on IP3R activity but not on PKM2. However, the tyrosine kinase Lck, which also interacts with the D5SD sequence, is expressed neither in HeLa WT nor PKM2 KO cells, and we can also exclude a role for PKM1, which is upregulated in HeLa PKM2 KO cells, indicating that the TAT-D5SD peptide has a more complex mode of action than anticipated. [ABSTRACT FROM AUTHOR]

PKM2 mediates the Warburg effects and is crucial for tumorigenesis, but its role in hyperplastic skin disorders remains elusive. In this study, we investigated the function of PKM2 in psoriatic keratinocytes. We found that PKM2 expression and its nuclear translocation were induced in the epidermis of psoriasis patients, contributing to aerobic glycolysis and cell growth. Moreover, mass spectrometry combined with immunoprecipitation analysis revealed that PKM2 could interact with TRIM33, an E3 ubiquitin ligase in the nucleus, and this interaction is critical for the nuclear retention of PKM2. As a result of TRIM33‐mediated ubiquitination, PKM2 nuclear protein kinase function is promoted, thus leading to the phosphorylation of STAT3. In addition, blocking PKM2 nuclear translocation abrogated TRIM33‐triggered glycolysis and cell proliferation in keratinocytes. Taken together, our experiments demonstrate that ubiquitination regulates the nuclear retention of PKM2 in keratinocytes. Moreover, our results highlight a novel mechanism accounting for the metabolic reprogramming of keratinocytes in psoriasis patients. [ABSTRACT FROM AUTHOR]

Background: Glycolysis under normoxic conditions, known as the Warburg effect, confers a selective advantage for the survival and proliferation of many tumors. In this study, we investigated the role of estrogen-related receptor gamma (ESRRG) in metabolic reprogramming in esophageal squamous cell carcinoma (ESCC). Methods: Bioinformatics analysis indicated that ESRRG expression was decreased in ESCC tissue and associated with poor clinical outcomes. We also examined the effects of altered ESRRG expression on the proliferation and metabolic reprogramming of ESCC cells. We explored the impact of ESRRG on Pyruvate kinase M2 (PKM2) expression and malignant behavior in ESCC. Results: Our study revealed the inhibitory effects of ESRRG on the growth, tumorigenesis, and glycolysis activity of ESCC cells, which were mediated by the downregulation of PKM2 expression. We further demonstrated that ESRRG directly interacts with the PKM2 promoter to inhibit its activity in ESCC. Notably, the ESRRG-specific agonist, DY131, inhibited ESCC cell proliferation and glycolysis activity by modulating genes in the glycolysis pathway. Moreover, we verified that DY131 exhibits enhanced activity as an immune checkpoint inhibitor, considering the significance of the ESRRG-PKM2 axis in the lactate regulation of ESCC cells. Conclusion: Our findings provide novel insights into the role of ESRRG-PKM2 signaling in regulating ESCC cell metabolism and immune checkpoint regulation. Additionally, we suggest that DY131 holds promise as a promising therapeutic agent for ESCC treatment. [ABSTRACT FROM AUTHOR]

Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver injury. However, the underlying mechanisms appear to be multifaceted and there are few effective treatments. In this study, we used the 2′-Hydroxycinnamaldehyde (HCA), an active ingredient extracted from cinnamon stem bark to evaluate the therapeutic effect against APAP-induced ALI. The results indicated that pyruvate kinase M2 (PKM2)-mediated aerobic glycolysis may activate NLRP3 inflammasome in APAP-induced ALI, However, this process was prevented by HCA. Additionally, overexpression of PKM2 by adeno-associated virus (AAV9-PKM2) in vivo and plasmid (PKM2-OE) in vitro reversed the inhibition of NLRP3 inflammasome by HCA. Intriguingly, the HCA-triggered repressive pyroptosis was mediated through dephosphorylation and nuclear translocation of PKM2. Furthermore, the therapeutic effect of HCA on APAP-induced ALI was achieved by partially stimulating the Akt-mTOR signaling pathway, thus inhibiting the PKM2-NLRP3 axis. These findings elucidate that a potential drug to the clinical treatment of APAP overdose by HCA.

Cutaneous wound healing is a complex and dynamic process with high energy demand. The activation of glycolysis is essential for restoring the structure and function of injured tissues in wounds. Pyruvate kinase M2 (PKM2) is an enzyme that plays a crucial role in the last step of glycolysis. PKM2-mediated glycolysis is known to play an important role in diseases related to regeneration and inflammation. However, the role of PKM2 in wound healing has not been fully elucidated. In this study, we found that PKM2 expression and pyruvate kinase (PK) activity were increased with the activation of Wnt/β-catenin signaling during wound healing in mice. TEPP-46, an allosteric activator of PKM2, enhanced HaCaT human keratinocyte migration and cutaneous wound healing with an increment of PK activity. Moreover, we confirmed the effect of co-treatment with TEPP-46 and KY19382, a Wnt/β-catenin signaling activator through the interference with the CXXC-type zinc finger protein 5 (CXXC5) Dishevelled interaction, on wound healing. The combination treatment significantly accelerated wound healing, which was confirmed by the expression level of PCNA, keratin 14, and α-SMA. Furthermore, co-treatment induced angiogenesis in the wound beds. Overall, activation of both glycolysis and Wnt/β-catenin signaling has the potential to be used as a therapeutic approach for wound healing. [ABSTRACT FROM AUTHOR]

Hepatic diseases have constituted a significant global problem for over two decades, numerous factors contribute to these diseases, and most eventually result in hepatocellular carcinoma. A particular pivotal factor responsible for hepatic diseases is the abnormal functioning of various metabolic processes. Pyruvate kinase is a crucial regulator of the glycolytic pathway, and overexpression of pyruvate kinase isoform M2 (PKM2) has been observed with various hepatic abnormalities due to genetic malfunctioning and other contributing factors. The present scenario for diagnosing and treating hepatic diseases includes surgery and immunosuppressant therapies. Kinase modulation may also be a potential therapeutic measure for rectifying hepatic diseases, and this can serve as a potential approach. This review summarizes the malfunctions and significance of PKM2 regulation and explores the potential of PKM2 as a target for treating hepatic abnormalities. [ABSTRACT FROM AUTHOR]

Abstract Background Lung cancer is the most common malignancy in the world and a growing number of researches have focused on its metabolic characteristics. Studies have shown that the long non‐coding RNA (lncRNA) HOXA11‐AS is aberrantly expressed in many tumors. However, the role of HOXA11‐AS in lung adenocarcinoma (LUAD) glycolysis and other energy metabolism pathways has not been characterized. Method The mRNA levels of HOXA11‐AS, microRNA‐148b‐3p (miR‐148b‐3p), and pyruvate kinase M2 (PKM2) were detected using qRT‐PCR. The expression levels of proteins were measured using immunohistochemistry and western blot. The CCK‐8, EdU, and colony formation assays were used to assess proliferation. Glycolytic changes were assessed by measuring lactate production, ATP production, and 18F‐FDG uptake. Bioinformatics analysis and dual‐luciferase reporter assays were used to characterize the relationship between HOXA11‐AS, miR‐148b‐3p, and PKM2. Proliferation and glycolytic changes were analyzed in xenograft tumor experiments using Micro‐PET imaging after downregulation of HOXA11‐AS in vivo. Results The expression of HOXA11‐AS was markedly increased in LUAD, and was strongly associated with a poor prognosis. In addition, HOXA11‐AS promoted proliferation and glycolysis in LUAD, and miR‐148b‐3p inhibited proliferation and glycolysis in LUAD. Mechanistically, HOXA11‐AS positively regulated PKM2 expression by binding to miR‐148b‐3p, thereby promoting LUAD proliferation and glycolysis. In addition, HOXA11‐AS inhibited LUAD xenograft growth and glycolysis via upregulation of miR‐148b‐3p expression and downregulation of PKM2 expression in vivo. Conclusions These results showed that HOXA11‐AS enhanced LUAD proliferation and glycolysis via the miR‐148b‐3p/PKM2 axis. The findings in this paper expanded our understanding of the molecular mechanisms of LUAD tumorigenesis and glycolysis and showed that HOXA11‐AS could be useful as a diagnostic and prognostic marker for LUAD. 18F‐FDG PET/CT can be used to visually evaluate the therapeutic effect of targeting HOXA11‐AS.

Abstract Background Chronic inflammation is a hallmark of cancer, and it can be stimulated by many factors. Substance P (SP), through binding to neurokinin 1 receptor (NK1R), and pyruvate kinase M2 (PKM2) play critical roles in cancer development and progression via modulating the tumor microenvironment. This study aimed to investigate the prognostic significance of SP and PKM2 in combination with NK1R and Ki-67 in hormone receptor negative (HR-ve) breast cancer. Methods Immunohistochemical expression levels of SP, NK1R, PKM2, and Ki-67 were measured in 144 paraffin-embedded breast cancer tissues (77 h -ve and 67 h + ve). SP, NK1R, and PKM2 were scored semiquantitatively, while Ki-67 was obtained by the percentage of total number of tumor cells with nuclear staining. The optimal cutoff value for SP, NK1R, PKM2, and Ki-67 were assessed by Cutoff Finder. Results High SP expression in HR -ve breast cancer was associated with TNM stage (p = 0.020), pT stage (p = 0.035), pN stage (p = 0.002), axillary lymph node metastasis (p = 0.003), and NK1R expression level (p = 0.010). In HR + ve breast cancer, SP expression was associated with HER2 status (p = 0.001) and PKM2 expression level (p = 0.012). Regarding PKM2 expression level, it significantly associated with HER2 status (p = 0.001) and history of DCIS (p = 0.046) in HR-ve tumors, and with HER2 status (p

Increased glycolytic in fibroblast‐like synoviocytes (FLS) of rheumatoid arthritis (RA) not only contributes to early‐stage disease pathogenesis but leads to sustained proliferation of FLS. Given the importance of PKM2 in glycolysis and apoptosis, PKM2 is considered a potential therapeutic and drug discovery target in RA. Total saponins of anemarrhena (TSA), a class of steroid saponins, originated from Anemarrhena asphodeloides Bge. In this study, we verified that 200 mg/kg TSA could significantly alleviate inflammation and the pathological characteristics of RA and inhibit synovial hyperplasia in AA rats. We confirmed that sarsasapogenin (SA) was the principal active ingredient absorbed into the blood of TSA by the UPLC/Q Exactive MS test. Then we used TNF‐α‐induced MH7A to get the conclusion that 20 μM SA could effectively inhibit the glycolysis by inhibiting the activity of PKM2 tetramer and glucose uptake. Moreover, 20 μM SA could suppress proliferation, migration, invasion, and cytokine release of FLS, interfere with the growth cycle of FLS, and induce FLS apoptosis by depressing the phosphorylation of PKM2. At last, In‐1, a potent inhibitor of the PKM2 was used to reverse verify the above results. Taken together, the key mechanisms of SA on RA treatment through downregulating the activity of PKM2 tetramer and phosphorylation of PKM2 inhibited pathological glycolysis and induced apoptosis to exert inhibition on the proliferation and invasion of RA FLS. [ABSTRACT FROM AUTHOR]

Upregulation of pyruvate kinase M2 (PKM2) is critical for the orchestration of metabolism and inflammation in critical illness, while autophagic degradation is a recently revealed mechanism that counter-regulates PKM2. Accumulating evidence suggests that sirtuin 1 (SIRT1) function as a crucial regulator in autophagy. The present study investigated whether SIRT1 activator would downregulate PKM2 in lethal endotoxemia via promotion of its autophagic degradation. The results indicated that lethal dose of lipopolysaccharide (LPS) exposure decreased the level of SIRT1. Treatment with SRT2104, a SIRT1 activator, reversed LPS-induced downregulation of LC3B-II and upregulation of p62, which was associated with reduced level of PKM2. Activation of autophagy by rapamycin also resulted in reduction of PKM2. The decline of PKM2 in SRT2104-treated mice was accompanied with compromised inflammatory response, alleviated lung injury, suppressed elevation of blood urea nitrogen (BUN) and brain natriuretic peptide (BNP), and improved survival of the experimental animals. In addition, coadministration of 3-methyladenine, an autophagy inhibitor, or Bafilomycin A1, a lysosome inhibitor, abolished the suppressive effects of SRT2104 on PKM2 abundance, inflammatory response and multiple organ injury. Therefore, promotion of autophagic degradation of PKM2 might be a novel mechanism underlying the anti-inflammatory benefits of SIRT1 activator. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH), a fatal disease with an insidious onset and rapid progression, shows characteristics such as increases in pulmonary circulatory resistance and pulmonary arterial pressure, and progressive right heart failure. Shikonin can reduce right ventricular systolic pressure in chronically hypoxic mice. However, the mechanisms underlying the protective effect of shikonin against PAH pathogenesis have only been sporadically iden‑ tified. The present study evaluated whether inhibiting the expression of pyruvate kinase M2 (PKM2) contributed to the improvement of pulmonary vascular remodeling in PAH rats induced by monocrotaline (MCT) treatment. Hemodynamic parameters were assessed using echocardiography and right ventricular catheterization. Right ventricular hypertrophy index analysis and hematoxylin and eosin staining were used to evaluate the degree of pulmonary vascular and right heart remodeling. Moreover, PKM2, p‑PKM2, ERK, p‑ERK, glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA) protein expression levels were semi‑quantified using western blotting. The expression and distribution of PKM2 were assessed using immunofluorescence microscopy. The present study demonstrated that MCT treatment caused pulmonary arterial hypertension and pulmonary vascular remodeling in experimental rats. Shikonin improved hemody‑ namics and pulmonary vascular remodeling in MCT‑induced PAH rats, decreased aerobic glycolysis and downregulated PKM2, p‑PKM2, p‑ERK, GLUT 1 and LDHA protein expres‑ sion levels. Shikonin improved experimental pulmonary arterial hypertension hemodynamics and pulmonary vascular remodeling at least partly through the inhibition of PKM2 and the resultant suppression of aerobic glycolysis. These results provide a novel understanding of possible new treatment targets for PAH. [ABSTRACT FROM AUTHOR]

Retinal ischemia plays a vital role in vision-threatening retinal ischemic disorders, such as diabetic retinopathy, age-related macular degeneration, glaucoma, etc. The aim of this study was to investigate the effects of S-allyl L-cysteine (SAC) and its associated therapeutic mechanism. Oxidative stress was induced by administration of 500 μM H2O2 for 24 h; SAC demonstrated a dose-dependent neuroprotective effect with significant cell viability effects at 100 μM, and it concurrently downregulated angiogenesis factor PKM2 and inflammatory biomarker MCP-1. In a Wistar rat model of high intraocular pressure (HIOP)-induced retinal ischemia and reperfusion (I/R), post-administration of 100 μM SAC counteracted the ischemic-associated reduction of ERG b-wave amplitude and fluorogold-labeled RGC reduction. This study supports that SAC could protect against retinal ischemia through its anti-oxidative, anti-angiogenic, anti-inflammatory, and neuroprotective properties.

Renal fibrosis is a hallmark of diabetic nephropathy (DN) and is characterized by an epithelial-to-mesenchymal transition (EMT) program and aberrant glycolysis. The underlying mechanisms of renal fibrosis are still poorly understood, and existing treatments are only marginally effective. Therefore, it is crucial to comprehend the pathophysiological mechanisms behind the development of renal fibrosis and to generate novel therapeutic approaches. Acrolein, an α-,β-unsaturated aldehyde, is endogenously produced during lipid peroxidation. Acrolein shows high reactivity with proteins to form acrolein-protein conjugates (Acr-PCs), resulting in alterations in protein function. In previous research, we found elevated levels of Acr-PCs along with kidney injuries in high-fat diet-streptozotocin (HFD-STZ)-induced DN mice. This study used a proteomic approach with an anti-Acr-PC antibody followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis to identify several acrolein-modified protein targets. Among these protein targets, pyruvate kinase M2 (PKM2) was found to be modified by acrolein at Cys358, leading to the inactivation of PKM2 contributing to the pathogenesis of renal fibrosis through HIF1α accumulation, aberrant glycolysis, and upregulation of EMT in HFD-STZ-induced DN mice. Finally, PKM2 activity and renal fibrosis in DN mice can be reduced by acrolein scavengers such as hydralazine and carnosine. These results imply that acrolein-modified PKM2 contributes to renal fibrosis in the pathogenesis of DN.

Background: Chronic inflammation is a hallmark of cancer, and it can be stimulated by many factors. Substance P (SP), through binding to neurokinin 1 receptor (NK1R), and pyruvate kinase M2 (PKM2) play critical roles in cancer development and progression via modulating the tumor microenvironment. This study aimed to investigate the prognostic significance of SP and PKM2 in combination with NK1R and Ki-67 in hormone receptor negative (HR-ve) breast cancer. Methods: Immunohistochemical expression levels of SP, NK1R, PKM2, and Ki-67 were measured in 144 paraffin-embedded breast cancer tissues (77 h -ve and 67 h + ve). SP, NK1R, and PKM2 were scored semiquantitatively, while Ki-67 was obtained by the percentage of total number of tumor cells with nuclear staining. The optimal cutoff value for SP, NK1R, PKM2, and Ki-67 were assessed by Cutoff Finder. Results: High SP expression in HR -ve breast cancer was associated with TNM stage (p = 0.020), pT stage (p = 0.035), pN stage (p = 0.002), axillary lymph node metastasis (p = 0.003), and NK1R expression level (p = 0.010). In HR + ve breast cancer, SP expression was associated with HER2 status (p = 0.001) and PKM2 expression level (p = 0.012). Regarding PKM2 expression level, it significantly associated with HER2 status (p = 0.001) and history of DCIS (p = 0.046) in HR-ve tumors, and with HER2 status (p < 0.001) and SP expression level (p = 0.012) in HR + ve tumors. Survival analysis revealed that high SP level negatively impacted overall survival in HR-ve tumors that had low NK1R level (p = 0.021). Moreover, high SP negatively impacted overall survival in HR-ve tumors that had low Ki-67 level (p = 0.005). High PKM2 negatively impacted overall survival in HR-ve cases with low SP (p = 0.047). Conclusion: Combined expression levels of SP with NK1R or Ki-67, and PKM2 with SP could be used to predict survival in breast cancer patients with HR-ve tumors. Our findings suggest a role of SP/NK1R pathway and PKM2 in HR-ve breast cancer pathogenesis which should be further investigated to unveil the underlying molecular mechanisms. [ABSTRACT FROM AUTHOR]