Hexokinase 2 (HK2), the tumor promoter in glioma, is downregulated by miR-218/Bmi1 pathway

Methods of miRNA delivery and possibilities of their application in neuro-oncology

In the current phase of medical progress, practical neuro-oncology faces critical challenges. These include the quest for and development of innovative methodological approaches, as well as the enhancement of conventional therapies to boost their efficacy in treating brain tumors, especially the malignant varieties. Recent strides in molecular and cellular biology, molecular genetics, and immunology have charted the primary research pathways in the development of new anti-cancer medications, with a particular focus on microRNA (miRNA)-based therapy. MiRNAs possess the ability to function as suppressors of tumor growth while also having the potential to act as oncogenes. MiRNAs wield control over numerous processes within the human body, encompassing tumor growth, proliferation, invasion, metastasis, apoptosis, angiogenesis, and immune responses. A significant impediment to enhancing the efficacy of brain tumor treatment lies in the unresolved challenge of traversing the blood-brain barrier (BBB) and blood-tumor barrier (BTB) to deliver therapeutic agents directly to the tumor tissue. Presently, there is a worldwide effort to conduct intricate research and design endeavors aimed at creating miRNA-based dosage forms and delivery systems that can effectively target various structures within the central nervous system (CNS). MiRNA-based therapy stands out as one of the most promising domains in neuro-oncology. Hence, the development of efficient and safe methods for delivering miRNA agents to the specific target cells within brain tumors is of paramount importance. In this study, we will delve into recent findings regarding various methods for delivering miRNA agents to brain tumor cells. We will explore the advantages and disadvantages of different delivery systems and consider some clinical aspects of miRNA-based therapy for brain tumors.

Biological and therapeutic viewpoints towards role of miR-218 in human cancers: Revisiting molecular interactions and future clinical translations

Understanding the exact pathogenesis of cancer is difficult due to heterogenous nature of tumor cells and multiple factors that cause its initiation and development. Treatment of cancer is mainly based on surgical resection, chemotherapy, radiotherapy and their combination, while gene therapy has been emerged as a new kind of therapy for cancer. Post-transcriptional regulation of genes has been of interest in recent years and among various types of epigenetic factors that can modulate gene expression, short non-coding RNAs known as microRNAs (miRNAs) have obtained much attention. The stability of mRNA decreases by miRNAs to repress gene expression. miRNAs can regulate tumor malignancy and biological behavior of cancer cells and understanding their function in tumorigenesis can pave the way towards developing new therapeutics in future. One of the new emerging miRNAs in cancer therapy is miR-218 that increasing evidence highlights its anti-cancer activity, while a few studies demonstrate its oncogenic function. The miR-218 transfection is promising in reducing progression of tumor cells. miR-218 shows interactions with molecular mechanisms including apoptosis, autophagy, glycolysis and EMT, and the interaction is different. miR-218 induces apoptosis, while it suppresses glycolysis, cytoprotective autophagy and EMT. Low expression of miR-218 can result in development of chemoresistance and radio-resistance in tumor cells and direct targeting of miR-218 as a key player is promising in cancer therapy. LncRNAs and circRNAs are nonprotein coding transcripts that can regulate miR-218 expression in human cancers. Moreover, low expression level of miR-218 can be observed in human cancers such as brain, gastrointestinal and urological cancers that mediate poor prognosis and low survival rate.

LOC554202 contributes to chordoma progression by sponging miR-377-3p and up-regulating SMAD3

Chordoma is a rare malignant bone tumor originating from the remnants of the notochord. Here, the role of long noncoding LOC554202 in chordoma progression and its associated mechanism were explored. Cell proliferation was analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide and colony formation assays. Flow cytometry was conducted to analyze cell apoptosis rate. The migration and invasion of chordoma cells were analyzed by transwell migration and invasion assays and wound healing assays. A xenograft tumor model was established in nude mice to explore the role of LOC554202 in regulating tumor growth in vivo . The interaction between microRNA-377-3p (miR-377-3p) and LOC554202 or sekelsky mothers against d PP (SMAD) family member 3 (SMAD3) was verified by dual-luciferase reporter and RNA immunoprecipitation assays. The glycolytic rate of chordoma cells was analyzed using glucose assay kit, lactic acid kit and ApoSENSOR ADP/ATP ratio assay kit. LOC554202 expression was upregulated in chordoma tissues and cell lines. LOC554202 silencing suppressed the proliferation, migration and invasion and induced the apoptosis of chordoma cells. LOC554202 knockdown restrained xenograft tumor growth in vivo . miR-377-3p was confirmed as a target of LOC554202, and miR-377-3p silencing largely overturned LOC554202 knockdown-mediated anti-tumor effects in chordoma cells. miR-377-3p interacted with the 3' untranslated region (3'UTR) of SMAD3 and miR-377-3p overexpression-mediated antitumor effects in chordoma cells were largely attenuated by SMAD3 overexpression. LOC554202 could positively regulate SMAD3 expression by sponging miR-377-3p in chordoma cells. LOC554202 contributed to the glycolysis of chordoma cells by targeting binding to miR-377-3p/SMAD3 axis. LOC554202 facilitated the proliferation, migration, invasion and glycolysis and inhibited the apoptosis of chordoma cells by mediating miR-377-3p/SMAD3 axis.

Metabolic targeting of malignant tumors: a need for systemic approach

PURPOSE

Dysregulated metabolism is now recognized as a fundamental hallmark of carcinogenesis inducing aggressive features and additional hallmarks. In this review, well-established metabolic changes displayed by tumors are highlighted in a comprehensive manner and corresponding therapeutical targets are discussed to set up a framework for integrating basic research findings with clinical translation in oncology setting.

METHODS

Recent manuscripts of high research impact and relevant to the field from PubMed (2000-2021) have been reviewed for this article.

RESULTS

Metabolic pathway disruption during tumor evolution is a dynamic process potentiating cell survival, dormancy, proliferation and invasion even under dismal conditions. Apart from cancer cells, though, tumor microenvironment has an acting role as extracellular metabolites, pH alterations and stromal cells reciprocally interact with malignant cells, ultimately dictating tumor-promoting responses, disabling anti-tumor immunity and promoting resistance to treatments.

CONCLUSION

In the field of cancer metabolism, there are several emerging prognostic and therapeutic targets either in the form of gene expression, enzyme activity or metabolites which could be exploited for clinical purposes; both standard-of-care and novel treatments may be evaluated in the context of metabolism rewiring and indeed, synergistic effects between metabolism-targeting and other therapies would be an attractive perspective for further research.

Metabolic Rewiring in Glioblastoma Cancer: EGFR, IDH and Beyond

Glioblastoma multiforme (GBM), a highly invasive and incurable tumor, is the humans’ foremost, commonest, and deadliest brain cancer. As in other cancers, distinct combinations of genetic alterations (GA) in GBM induce a diversity of metabolic phenotypes resulting in enhanced malignancy and altered sensitivity to current therapies. Furthermore, GA as a hallmark of cancer, dysregulated cell metabolism in GBM has been recently linked to the acquired GA. Indeed, Numerous point mutations and copy number variations have been shown to drive glioma cells’ metabolic state, affecting tumor growth and patient outcomes. Among the most common, IDH mutations, EGFR amplification, mutation, PTEN loss, and MGMT promoter mutation have emerged as key patterns associated with upregulated glycolysis and OXPHOS glutamine addiction and altered lipid metabolism in GBM. Therefore, current Advances in cancer genetic and metabolic profiling have yielded mechanistic insights into the metabolism rewiring of GBM and provided potential avenues for improved therapeutic modalities. Accordingly, actionable metabolic dependencies are currently used to design new treatments for patients with glioblastoma. Herein, we capture the current knowledge of genetic alterations in GBM, provide a detailed understanding of the alterations in metabolic pathways, and discuss their relevance in GBM therapy.

Potential of Novel Methyl Jasmonate Analogs as Anticancer Agents to Metabolically Target HK-2 Activity in Glioblastoma Cells

Change in the energy metabolism of cancer cells, which display significant differences compared to normal cells, is a rising phenomenon in developing new therapeutic approaches against cancers. One of the metabolic enzymes, hexokinase-II (HK-II) is involved in glycolysis, and inhibiting the HK-II activity may be a potential metabolic target for cancer therapy as most of the drugs in clinical use act on DNA damage. Methyl jasmonate (MJ) is one of the compounds blocking HK-II activity in cancer cells. In a previous study, we showed that the novel MJ analogs inhibit HK-II activity through VDAC detachment from the mitochondria. In this study, to evaluate the potential of targeting HK-2 activity, through patient cohort analysis, we first determined HK-2 expression levels and prognostic significance in highly lethal glioblastoma (GBM) brain tumor. We then examined the in vitro therapeutic effects of the novel analogs in the GBM cells. Here, we report that, among all, compound-10 (C-10) showed significant in vitro therapeutic efficacy as compared to MJ which is in use for preclinical and clinical studies. Afterward, we analyzed cell death triggered by C-10 in two different GBM cell lines. We found that C-10 treatment increased the apoptotic/necrotic cells and autophagy in GBM cells. The newly developed analog, C-10, was found to be lethal against GBM by the activation of cell death authorities, mostly in a necrotic and autophagic fashion at the early stages of the treatment. Considering that possibly decreased intracellular ATP levels by C-10 mediated inhibition of HK-2 activity and disabled VDAC interaction, a more detailed analysis of HK-2 inhibition-mediated cell death can provide a deep understanding of the mechanism of action on the oncosis/necroptosis axis. These findings provide an option to design clinically relevant and effective novel HK-II inhibitors and suggest novel MJ analogs to further study them as potential anticancer agents against GBM.

Expression of HK2, PKM2, and PFKM Is Associated with Metastasis and Late Disease Onset in Breast Cancer Patients

The reprogramming of energy metabolism is one of the hallmarks of cancer and is crucial for tumor progression. Altered aerobic glycolysis is a well-known characteristic of cancer cell metabolism. In the present study, the expression profiles of key metabolic genes (HK2, PFKM, and PKM2) were assessed in the breast cancer cohort of Pakistan using quantitative polymerase chain reaction (qPCR) and IHC. Expression patterns were correlated with molecular subtypes and clinical parameters in the patients. A significant upregulation of key glycolytic genes was observed in tumor samples in comparison to their adjacent controls (p < 0.0001). The expression of the studied glycolytic genes was significantly increased in late clinical stages, positive nodal involvement, and distant metastasis (p < 0.05). HK2 and PKM2 were found to be upregulated in luminal B, whereas PFKM was overexpressed in the luminal A subtype of breast cancer. The genes were positively correlated with the proliferation marker Ki67 (p < 0.001). Moreover, moderate positive linear correlations between HK2 and PKM2 (r = 0.476), HK2 and PFKM (r = 0.473), and PKM2 and PFKM (r = 0.501) were also observed (p < 0.01). These findings validate that the key regulatory genes in glycolysis can serve as potential biomarkers and/or molecular targets for breast cancer management. However, the clinical significance of these molecules needs to be further validated through in vitro and in vivo experiments.

NOX2-Induced High Glycolytic Activity Contributes to the Gain of COL5A1-Mediated Mesenchymal Phenotype in GBM

Simple Summary

Glioblastoma multiforme (GBM) is the most aggressive type of glioma and exhibits extensive heterogeneity and poor prognosis with a high recurrence rate. Among the genetic alterations in GBM with different phenotypic states, a mesenchymal subtype has been associated with a worse outcome in patients with GBM. The mechanisms for the gain of the mesenchymal subtype in GBM remain unclear. Our aim was to investigate whether NOX2-induced high glycolytic activity could contribute to the gain of the mesenchymal phenotype in GBM. We revealed that NOX2-induced high glycolytic activity can induce the gain of the COL5A1-mediated mesenchymal phenotype in GBM. Our findings will provide the molecular mechanism by which NOX2 contributes to the gain of mesenchymal phenotype in GBM.

Abstract

The alteration of the cellular metabolism is a hallmark of glioma. The high glycolytic phenotype is a critical factor in the pathogenesis of high-grade glioma, including glioblastoma multiforme (GBM). GBM has been stratified into three subtypes as the proneural, mesenchymal, and classical subtypes. High glycolytic activity was found in mesenchymal GBM relative to proneural GBM. NADPH oxidase 2 (NOX2) has been linked to cellular metabolism and epithelial-mesenchymal transition (EMT) in tumors. The role of NOX2 in the regulation of the high glycolytic phenotype and the gain of the mesenchymal subtype in glioma remain unclear. Here, our results show that the levels of NOX2 were elevated in patients with GBM. NOX2 induces hexokinase 2 (HK2)-dependent high glycolytic activity in U87MG glioma cells. High levels of NOX2 are correlated with high levels of HK2 and glucose uptake in patients with GBM relative to benign glioma. Moreover, NOX2 increases the expression of mesenchymal-subtype-related genes, including COL5A1 and FN1 in U87MG glioma cells. High levels of NOX2 are correlated with high levels of COL5A1 and the accumulation of extracellular matrix (ECM) in patients with GBM relative to benign glioma. Furthermore, high levels of HK2 are correlated with high levels of COL5A1 in patients with GBM relative to benign glioma. Our results suggest that NOX2-induced high glycolytic activity contributes to the gain of the COL5A1-mediated mesenchymal phenotype in GBM.

High Expression of Glycolytic Genes in Clinical Glioblastoma Patients Correlates With Lower Survival

Glioblastoma (GBM), the most aggressive brain tumor, is associated with a median survival at diagnosis of 16–20 months and limited treatment options. The key hallmark of GBM is altered tumor metabolism and marked increase in the rate of glycolysis. Aerobic glycolysis along with elevated glucose consumption and lactate production supports rapid cell proliferation and GBM growth. In this study, we examined the gene expression profile of metabolic targets in GBM samples from patients with lower grade glioma (LGG) and GBM. We found that gene expression of glycolytic enzymes is up-regulated in GBM samples and significantly associated with an elevated risk for developing GBM. Our findings of clinical outcomes showed that GBM patients with high expression of HK2 and PKM2 in the glycolysis related genes and low expression of genes involved in mitochondrial metabolism-SDHB and COX5A related to tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS), respectively, was associated with poor patient overall survival. Surprisingly, expression levels of genes involved in mitochondrial oxidative metabolism are markedly increased in GBM compared to LGG but was lower compared to normal brain. The fact that in GBM the expression levels of TCA cycle and OXPHOS-related genes are higher than those in LGG patients suggests the metabolic shift in GBM cells when progressing from LGG to GBM. These results are an important step forward in our understanding of the role of metabolic reprogramming in glioma as drivers of the tumor and could be potential prognostic targets in GBM therapies.

Circular RNA circ-LARP1B contributes to cutaneous squamous cell carcinoma progression by targeting microRNA-515-5p/TPX2 microtubule nucleation factor axis

Circular RNAs (circRNAs) have shown pivotal regulatory roles in tumorigenesis and progression. Our purpose was to analyze the role of circRNA La ribonucleoprotein 1B (circ-LARP1B; hsa_circ_0070934) in cutaneous squamous cell carcinoma (CSCC) progression and its associated mechanism. Cell viability, colony formation ability, migration, and invasion were analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide (MTT) assay, colony formation assay, wound healing assay, and transwell invasion assay. Flow cytometry was performed to analyze cell apoptosis and cell cycle progression. Cell glycolytic metabolism was analyzed using Glucose Uptake Colorimetric Assay kit, Lactate Assay Kit II, and ATP colorimetric Assay kit. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to verify the interaction between microRNA-515-5p (miR-515-5p) and circ-LARP1B or TPX2 microtubule nucleation factor (TPX2). Circ-LARP1B expression was up-regulated in CSCC tissues and cell lines. Circ-LARP1B knockdown suppressed cell viability, colony formation ability, migration, invasion, cell cycle progression, and glycolysis and triggered cell apoptosis in CSCC cells. miR-515-5p was a direct target of circ-LARP1B in CSCC cells, and circ-LARP1B silencing-mediated anti-tumor effects were largely counteracted by miR-515-5p knockdown. miR-515-5p directly interacted with the 3' untranslated region (3'UTR) of TPX2. TPX2 overexpression largely overturned miR-515-5p-mediated anti-tumor effects in CSCC cells. Circ-LARP1B could up-regulate TPX2 expression by sponging miR-515-5p in CSCC cells. Circ-LARP1B knockdown suppressed tumor growth in vivo. In conclusion, circ-LARP1B contributed to CSCC progression by targeting miR-515-5p/TPX2 axis. The circ-LARP1B/miR-515-5p/TPX2 axis might provide novel therapeutic targets for CSCC patients.

circHUWE1 Exerts an Oncogenic Role in Inducing DDP-Resistant NSCLC Progression Depending on the Regulation of miR-34a-5p/TNFAIP8

Background

Circular RNAs (circRNAs) are reported as competing endogenous RNAs (ceRNAs) and play key roles in non-small-cell lung cancer (NSCLC) progression. Thus, this study was aimed at clarifying underlying molecular mechanisms of circHUWE1 in NSCLC.

Methods

The quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analyses were used for examining circHUWE1, microRNA-34a-5p (miR-34a-5p), and tumor necrosis factor alpha-induced protein 8 (TNFAIP8). IC₅₀ of cisplatin (DDP) in A549/DDP and H1299/DDP cells and cell viability were analyzed by the Cell Counting Kit 8 (CCK-8) assay. Colony forming assay was performed to assess colony forming ability. Cell apoptosis and cell cycle distribution were determined by flow cytometry. Migrated and invaded cell numbers were examined by transwell assay. The association among circHUWE1, miR-34a-5p, and TNFAIP8 was analyzed by dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft experiment was applied to clarify the functional role of circHUWE1 in vivo.

Results

circHUWE1 was upregulated in NSCLC tissues and cells, especially in DDP-resistant groups. circHUWE1 downregulation inhibited DDP resistance, proliferation, migration, and invasion while it induced apoptosis and cell cycle arrest of DDP-resistant NSCLC cells, which was overturned by silencing of miR-34a-5p. TNFAIP8 was a functional gene of miR-34a-5p, and the suppressive effects of miR-34a-5p overexpression on DDP-resistant NSCLC progression were dependent on the suppression of TNFAIP8. circHUWE1 inhibition also delayed tumor growth of DDP-resistant NSCLC cells.

Conclusion

circHUWE1 functioned as a promoter in DDP-resistant NSCLC by interaction with miR-34a-5p-TNFAIP8 networks, providing novel insight into DDP-resistant NSCLC diagnosis and treatment.

Melatonin Protects Chronic Kidney Disease Mesenchymal Stem/Stromal Cells against Accumulation of Methylglyoxal via Modulation of Hexokinase-2 Expression

Treatment options for patients with chronic kidney disease (CKD) are currently limited; therefore, there has been significant interest in applying mesenchymal stem/stromal cell (MSC)-based therapy to treat CKD. However, MSCs harvested from CKD patients tend to show diminished viability and proliferation due to sustained exposure to uremic toxins in the CKD environment, which limits their utility for cell therapy. The application of melatonin has been demonstrated to improve the therapeutic efficacy of MSCs derived from and engrafted to tissues in patients suffering from CKD, although the underlying biological mechanism has not been elucidated. In this study, we observed overexpression of hexokinase-2 (HK2) in serum samples of CKD patients and MSCs harvested from an adenine-fed CKD mouse model (CKD-mMSCs). HK2 upregulation led to increased production levels of methylglyoxal (MG), a toxic metabolic intermediate of abnormal glycolytic processes. The overabundance of HK2 and MG was associated with impaired mitochondrial function and low cell proliferation in CKD-mMSCs. Melatonin treatment inhibited the increases in HK2 and MG levels, and further improved mitochondrial function, glycolytic metabolism, and cell proliferation. Our findings suggest that identifying and characterizing metabolic regulators such as HK2 in CKD may improve the efficacy of MSCs for treating CKD and other kidney disorders.

An understanding of mitochondria and its role in targeting nanocarriers for diagnosis and treatment of cancer

Nanotechnology has changed the entire paradigm of drug targeting and has shown tremendous potential in the area of cancer therapy due to its specificity. In cancer, several targets have been explored which could be utilized for the better treatment of disease. Mitochondria, the so-called powerhouse of cell, portrays significant role in the survival and death of cells, and has emerged as potential target for cancer therapy. Direct targeting and nanotechnology based approaches can be tailor-made to target mitochondria and thus improve the survival rate of patients suffering from cancer. With this backdrop, in present review, we have reemphasized the role of mitochondria in cancer progression and inhibition, highlighting the different targets that can be explored for targeting of disease. Moreover, we have also summarized different nanoparticulate systems that have been used for treatment of cancer via mitochondrial targeting.

Long non-coding RNA DLEU2 drives EMT and glycolysis in endometrial cancer through HK2 by competitively binding with miR-455 and by modulating the EZH2/miR-181a pathway

Background

Epithelial-to-mesenchymal transition (EMT) and aerobic glycolysis are fundamental processes implicated in cancer metastasis. Although increasing evidence demonstrates an association between EMT induction and enhanced aerobic glycolysis in human cancer, the mechanisms linking these two conditions in endometrial cancer (EC) cells remain poorly defined.

Methods

We characterized the role and molecular mechanism of the glycolytic enzyme hexokinase 2 (HK2) in mediating EMT and glycolysis and investigated how long noncoding RNA DLEU2 contributes to the stimulation of EMT and glycolysis via upregulation of HK2 expression.

Results

HK2 was highly expressed in EC tissues, and its expression was associated with poor overall survival. Overexpression of HK2 effectively promoted EMT phenotypes and enhanced aerobic glycolysis in EC cells via activating FAK and its downstream ERK1/2 signaling. Moreover, microRNA-455 (miR-455) served as a tumor suppressor by directly interacting with HK2 mRNA and inhibiting its expression. Furthermore, DLEU2 displayed a significantly higher expression in EC tissues, and increased DLEU2 expression was correlated with worse overall survival. DLEU2 acted as an upstream activator for HK2-induced EMT and glycolysis in EC cells through two distinct mechanisms: (i) DLEU2 induced HK2 expression by competitively binding with miR-455, and (ii) DLEU2 also interacted with EZH2 to silence a direct inhibitor of HK2, miR-181a.

Conclusions

This study identified DLEU2 as an upstream activator of HK2-driven EMT and glycolysis in EC cells and provided significant mechanistic insights for the potential treatment of EC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02018-1.

Dysregulation of the miR-1275/HK2 Axis Contributes to the Progression of Hypoxia/Reoxygenation-Induced Myocardial Injury

OBJECTIVE

This research was designed to investigate the function of miR-1275 in hypoxia/reoxygenation (H/R)-induced myocardial injury and its in-depth mechanism.

METHODS

Firstly, the differential expression of miR-1275 in patients with heart failure and healthy control were analyzed based on Gene Expression Omnibus (GEO) database. Then H/R model was constructed in vitro with AC16 cells. The qRT-PCR assay was performed to analyze the expression of miR-1275 in H/R-treated cells. Afterwards, CCK-8 assay and flow cytometry assay were carried out to detect the cells viability and apoptosis. Bioinformatics prediction, western blotting and dual-luciferase reporter assays were set to check the target gene of miR-1275. Finally, we used an Elisa to test the effect of miR-1275/HK2 axis on inflammatory factors.

RESULTS

We found that miR-1275 was highly expressed in patients with heart failure and H/R treated AC16 cells than that in control group, and inhibition of miR-1275 can alleviate induced-decrease of cell viability. Subsequently, we revealed that HK2 was a downstream target gene of miR-1275, which was lowly expressed in patients with heart failure. Furthermore, our data also suggested that inhibition of miR-1275 can significantly alleviate H/R-induced myocardial injury, which can also markedly decrease the concentration of pro-inflammatory factors TNF-α, IL-1 β and increase the concentration of anti-inflammatory factors IL-10 in H/R-treated AC16 cells, while knockdown of HK2 canceled the effect caused by miR-1275 deletion.

CONCLUSIONS

In summing, our results illustrated that miR-1275/HK2 axis act as a potential regulator to against H/R-induced AC16 cells injury through anti-inflammatory effect.

MicroRNA-615 functions as a tumor suppressor in osteosarcoma through the suppression of HK2

At present, the regulatory mechanisms of various microRNAs (miRNAs/miRs) have been elucidated in human cancers including osteosarcoma (OS). This study mainly focused on the role of miR-615 in OS, which has not yet been reported. Ninety-two OS tissues and normal samples were used in this study. Human osteoblast hFOB1.19 cells and OS cell line HOS were utilized to detect the expression of miR-615. The expression of miR-615 and gene expression were assessed by RT-qPCR and western blot analysis. Transwell, MTT and luciferase reporter assays were used to investigate the regulatory mechanism of miR-615 in OS. The results revealed that miR-615 expression was reduced in OS tissues and cells, and was associated with poor clinical outcomes and prognosis in OS patients. In addition, overexpression of miR-615 restrained cell viability and metastasis in OS. Furthermore, hexokinase 2 (HK2) was confirmed as a direct target of miR-615. Upregulation of HK2 was detected in OS tissues. The upregulation of HK2 weakened the tumor-suppressive effect of miR-615 in OS. Moreover, miR-615 blocked epithelial-mesenchymal transition (EMT) and inactivated the PI3K/AKT pathway in OS. To conclude, miR-615 acts as a tumor suppressor in OS, thus miR-615 can be used as a target for OS treatment.

Intrinsic and Extrinsic Modulators of the Epithelial to Mesenchymal Transition: Driving the Fate of Tumor Microenvironment

The epithelial to mesenchymal transition (EMT) is an evolutionarily conserved process. In cancer, EMT can activate biochemical changes in tumor cells that enable the destruction of the cellular polarity, leading to the acquisition of invasive capabilities. EMT regulation can be triggered by intrinsic and extrinsic signaling, allowing the tumor to adapt to the microenvironment demand in the different stages of tumor progression. In concomitance, tumor cells undergoing EMT actively interact with the surrounding tumor microenvironment (TME) constituted by cell components and extracellular matrix as well as cell secretome elements. As a result, the TME is in turn modulated by the EMT process toward an aggressive behavior. The current review presents the intrinsic and extrinsic modulators of EMT and their relationship with the TME, focusing on the non-cell-derived components, such as secreted metabolites, extracellular matrix, as well as extracellular vesicles. Moreover, we explore how these modulators can be suitable targets for anticancer therapy and personalized medicine.

Emerging Roles and Therapeutic Interventions of Aerobic Glycolysis in Glioma

Glioma is the most common type of intracranial malignant tumor, with a great recurrence rate due to its infiltrative growth, treatment resistance, intra- and intertumoral genetic heterogeneity. Recently, accumulating studies have illustrated that activated aerobic glycolysis participated in various cellular and clinical activities of glioma, thus influencing the efficacy of radiotherapy and chemotherapy. However, the glycolytic process is too complicated and ambiguous to serve as a novel therapy for glioma. In this review, we generalized the implication of key enzymes, glucose transporters (GLUTs), signalings and transcription factors in the glycolytic process of glioma. In addition, we summarized therapeutic interventions via the above aspects and discussed promising clinical applications for glioma.

Tanshinone IIA inhibits oral squamous cell carcinoma via reducing Akt-c-Myc signaling-mediated aerobic glycolysis

Aerobic glycolysis is one of the hallmarks of human cancer cells. Overexpression of hexokinase 2 (HK2) plays a crucial role in the maintaining of unlimited tumor cell growth. In the present study, we found that the oral squamous cell carcinoma (OSCC) cells exhibited an aerobic glycolysis phenotype. Moreover, HK2 is highly expressed in OSCC patient derived-tissues and cell lines. Depletion of HK2 inhibited OSCC cell growth in vitro and in vivo. With a natural product screening, we identified Tanshinone IIA (Tan IIA) as a potential anti-tumor compound for OSCC through suppressing HK2-mediated glycolysis. Tan IIA decreased glucose consumption, lactate production, and promoted intrinsic apoptosis in OSCC cells. The mechanism study revealed that Tan IIA inhibited the Akt-c-Myc signaling and promoted E3 ligase FBW7-mediated c-Myc ubiquitination and degradation, which eventually reduced HK2 expression at the transcriptional level. In summary, these results indicate that targeting HK2-mediated aerobic glycolysis is a promising anti-tumor strategy for OSCC treatment.

Xanthohumol suppresses glioblastoma via modulation of Hexokinase 2 -mediated glycolysis

Deregulation of aerobic glycolysis is a common phenomenon in human cancers, including glioblastoma (GBM). In the present study, we demonstrated that the natural compound xanthohumol has a profound anti-tumor effect on GBM via direct inhibition of glycolysis. Xanthohumol suppressed cell proliferation and colony formation of GBM cells, and significantly impaired glucose metabolism via inhibiting Hexokinase 2 (HK2) expression. We demonstrated that down-regulation of c-Myc was required for xanthohumol-induced decrease of HK2. Xanthohumol destabilization of c-Myc, and promoted FBW7-mediated ubiquitination of c-Myc. Xanthohumol attenuated Akt activity and inhibited the activation of GSK3β, resulted in c-Myc degradation. Overexpression of Myr-Akt1 significantly rescued xanthohumol-mediated c-Myc inhibition and glycolysis suppression. Finally, the xanthohumol-mediated down-regulation of the PI3-K/Akt-GSK3beta-FBW7 signaling axis promoted the destabilization of c-Myc. Finally, the animal results demonstrated that xanthohumol substantially inhibited tumor growth in vivo. Collectively, xanthohumol appears to be a promising new anti-tumor agent with the therapeutic potential for GBM.

Metabolic changes related to the IDH1 mutation in gliomas preserve TCA-cycle activity: An investigation at the protein level

The discovery of the IDH1 R132H (IDH1 mut) mutation in low-grade glioma and the associated change in function of the IDH1 enzyme has increased the interest in glioma metabolism. In an earlier study, we found that changes in expression of genes involved in the aerobic glycolysis and the TCA cycle are associated with IDH1 mut. Here, we apply proteomics to FFPE samples of diffuse gliomas with or without IDH1 mutations, to map changes in protein levels associated with this mutation. We observed significant changes in the enzyme abundance associated with aerobic glycolysis, glutamate metabolism, and the TCA cycle in IDH1 mut gliomas. Specifically, the enzymes involved in the metabolism of glutamate, lactate, and enzymes involved in the conversion of α-ketoglutarate were increased in IDH1 mut gliomas. In addition, the bicarbonate transporter (SLC4A4) was increased in IDH1 mut gliomas, supporting the idea that a mechanism preventing intracellular acidification is active. We also found that enzymes that convert proline, valine, leucine, and isoleucine into glutamate were increased in IDH1 mut glioma. We conclude that in IDH1 mut glioma metabolism is rewired (increased input of lactate and glutamate) to preserve TCA-cycle activity in IDH1 mut gliomas.

FOXE1 represses cell proliferation and Warburg effect by inhibiting HK2 in colorectal cancer

BACKGROUND

Low expression of FOXE1, a member of Forkhead box (FOX) transcription factor family that plays vital roles in cancers, contributes to poor prognosis of colorectal cancer (CRC) patients. However, the underlying mechanism remains unclear.

MATERIALS AND METHODS

The effects of FOXE1 on the growth of colon cancer cells and the expression of glycolytic enzymes were investigated in vitro and in vivo. Molecular biological experiments were used to reveal the underlying mechanisms of altered aerobic glycolysis. CRC tissue specimens were used to determine the clinical association of ectopic metabolism caused by dysregulated FOXE1.

RESULTS

FOXE1 is highly expressed in normal colon tissues compared with cancer tissues and low expression of FOXE1 is significantly associated with poor prognosis of CRC patients. Silencing FOXE1 in CRC cell lines dramatically enhanced cell proliferation and colony formation and promoted glucose consumption and lactate production, while enforced expression of FOXE1 manifested the opposite effects. Mechanistically, FOXE1 bound directly to the promoter region of HK2 and negatively regulated its transcription. Furthermore, the expression of FOXE1 in CRC tissues was negatively correlated with that of HK2.

CONCLUSION

FOXE1 functions as a critical tumor suppressor in regulating tumor growth and glycolysis via suppressing HK2 in CRC.

MiR-125b-5p suppresses the bladder cancer progression via targeting HK2 and suppressing PI3K/AKT pathway

Bladder cancer (BCa) is identified as the most common malignant solid cancer in the urogenital tract. Recently, dysregulation of miRNAs has received more attention because of its extensive role in the carcinogenesis of BCa. This research was designed to verify how miR-125b-5p be involved in BCa development. The expression of miR-125b-5p was detected in 52 pairs of BCa specimens and adjacent normal bladder specimens. The effects of miR-125b-5p on BCa viability, migration, and apoptosis in vitro were examined. We then examined directly target gene(s) of miR-125b-5p in BCa cells. Our data demonstrated that miR-125b-5p was decreased in BCa tissues and cell lines. Patients with low miR-125b-5p expression had obviously shorter 5-year survival time. Lower miR-125b-5p expression was significant correlated with distant metastasis, tumor size and lymph node metastasis. Ectopic expression of miR-125b-5p inhibited the BCa cell viability and migration and induced cell apoptosis. Furthermore, HK2 was confirmed regulated by miR-125b-5p. HK2 recovered miR-125b-5p-mediated suppression of BCa cell viability and migration. In addition, miR-125b-5p also exhibited suppressive effect on PI3K/AKT pathway. Overall, these data indicate that miR-125b-5p played a role in the suppressive effect on BCa by targeting HK2 through suppressing PI3K/AKT pathway and offer a potential therapeutic target for BCa.

Decreased FBP1 expression rewires metabolic processes affecting aggressiveness of glioblastoma

Radiotherapy is a standard treatment option for patients with glioblastoma (GBM). Although it has high therapeutic efficacy, some proportion of the tumor cells that survive after radiotherapy may cause side effects. In this study, we found that fructose 1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, was downregulated upon treatment with ionizing radiation (IR). Ets1, which was found to be overexpressed in IR-induced infiltrating GBM, was suggested to be a transcriptional repressor of FBP1. Furthermore, glucose uptake and extracellular acidification rates were increased upon FBP1 downregulation, which indicated an elevated glycolysis level. We found that emodin, an inhibitor of phosphoglycerate mutase 1 derived from natural substances, significantly suppressed the glycolysis rate and IR-induced GBM migration in in vivo orthotopic xenograft mouse models. We propose that the reduced FBP1 level reprogrammed the metabolic state of GBM cells, and thus, FBP1 is a potential therapeutic target regulating GBM metabolism following radiotherapy.

Exploiting Mitochondrial Vulnerabilities to Trigger Apoptosis Selectively in Cancer Cells

The transformation of normal cells to the cancerous stage involves multiple genetic changes or mutations leading to hyperproliferation, resistance to apoptosis, and evasion of the host immune system. However, to accomplish hyperproliferation, cancer cells undergo profound metabolic reprogramming including oxidative glycolysis and acidification of the cytoplasm, leading to hyperpolarization of the mitochondrial membrane. The majority of drug development research in the past has focused on targeting DNA replication, repair, and tubulin polymerization to induce apoptosis in cancer cells. Unfortunately, these are not cancer-selective targets. Recently, researchers have started focusing on metabolic, mitochondrial, and oxidative stress vulnerabilities of cancer cells that can be exploited as selective targets for inducing cancer cell death. Indeed, the hyperpolarization of mitochondrial membranes in cancer cells can lead to selective importing of mitocans that can induce apoptotic effects. Herein, we will discuss recent mitochondrial-selective anticancer compounds (mitocans) that have shown selective toxicity against cancer cells. Increased oxidative stress has also been shown to be very effective in selectively inducing cell death in cancer cells. This oxidative stress could lead to mitochondrial dysfunction, which in turn will produce more reactive oxygen species (ROS). This creates a vicious cycle of mitochondrial dysfunction and ROS production, irreversibly leading to cell suicide. We will also explore the possibility of combining these compounds to sensitize cancer cells to the conventional anticancer agents. Mitocans in combination with selective oxidative-stress producing agents could be very effective anticancer treatments with minimal effect on healthy cells.

Ammonia exposure induced abnormal expression of cytokines and heat shock proteins via glucose metabolism disorders in chicken neutrophils

Ammonia (NH₃) is a highly irritant, alkaline gas. Atmospheric emission of NH₃ was recognized as an environmental challenge. As a global issue, the NH₃ emission survey with spatially detailed information demonstrated that the sources of atmospheric NH₃ include agriculture (livestock wastes, fertilizers) and some industrial activities. As an environmental pollution, excessive NH₃ exposure can induce many bird dysfunction. Neutrophils respond to multiple invading pathogens through different mechanisms. In order to investigate the effect of NH₃ exposure on broilers' neutrophil, 1-day-old broilers were treated with/without NH₃ for 28 days. We extracted neutrophils from peripheral blood of chicken with/without NH₃ exposure and subsequently stimulated with PMA. Changes of cytokines and inflammatory bodies, heat shock proteins (HSPs), and glucose metabolism of neutrophil were examined in both cases. We not only explored that the index associated with inflammation changed due to NH₃ exposure but also observed the status of neutrophils which was treated with PMA stimulation. After NH₃ exposure, IL-1β and IL-6 were significantly increased on broilers neutrophil. Inflammatory-related factors (NLRP3, ASC, and caspase-1) were significantly elevated. The mRNA expression of HSP70 and HSP90 was increased significantly. All glucose metabolism indicators were reduced. In summary, we concluded that NH₃ enhanced inflammation and disrupted glucose metabolism, and increased the expression of HSPs and inflammatory factors. In addition, the sensitivity of neutrophils to exogenous stimuli was diminished. This information can not only be used to evaluate the damage of NH₃-spiked neutrophils to chickens, but also provide clues for human health pathophysiology caused by excess NH₃, providing valuable information for NH₃ risk management.

Suppressing glucose metabolism with epigallocatechin-3-gallate (EGCG) reduces breast cancer cell growth in preclinical models

Numerous studies propose that epigallocatechin-3-gallate (EGCG), an abundant polyphenol in green tea, has anti-cancer properties. However, its mechanism of action in breast cancer remains unclear. This study investigated the capacity of EGCG to suppress breast cancer cell growth in vitro and in vivo, characterizing the underlying mechanisms, focusing on the effect of EGCG on glucose metabolism. EGCG reduced breast cancer 4T1 cell growth in a concentration- (10-320 μM) and time- (12-48 h) dependent manner. EGCG induced breast cancer apoptotic cell death at 24 h, as evidenced by annexin V/PI, caspase 3, caspase 8 and caspase 9 activation. Furthermore, EGCG affected the expression of 16 apoptosis-related genes, and promoted mitochondrial depolarization. EGCG induced autophagy concentration-dependently in 4T1 cells by modulating the levels of the autophagy-related proteins Beclin1, ATG5 and LC3B. Moreover, EGCG affected glucose, lactate and ATP levels. Mechanistically, EGCG significantly inhibited the activities and mRNA levels of the glycolytic enzymes hexokinase (HK), phosphofructokinase (PFK), and lactic dehydrogenase (LDH), and to a lesser extent the activity of pyruvate kinase (PK). In addition, EGCG decreased the expression of hypoxia-inducible factor 1α (HIF1α) and glucose transporter 1 (GLUT1), critical players in regulating glycolysis. In vivo, EGCG reduced breast tumor weight in a dose-dependent manner, reduced glucose and lactic acid levels and reduced the expression of the vascular endothelial growth factor (VEGF). In conclusion, EGCG exerts an anti-tumor effect through the inhibition of key enzymes that participate in the glycolytic pathway and the suppression of glucose metabolism.