Tumor suppressor NDRG2 inhibits glycolysis and glutaminolysis in colorectal cancer cells by repressing c-Myc expression

NDRG2 regulates glucose metabolism and ferroptosis of OGD/R-treated astrocytes by the Wnt/β-catenin signaling

Ischemic stroke is one main type of cerebrovascular disorders with leading cause of death and disability worldwide. Astrocytes are the only nerve cell type storing glycogen in the brain, which regulate the glucose metabolism and handle the energy supply and survive of neurons. Astrocyte ferroptosis contributes to neuron injury in brain disorders. N-myc downstream-regulated gene 2 (NDRG2) has been implicated in the progression of brain diseases, including ischemic stroke. However, whether NDRG2 could affect the glucose metabolism and ferroptosis of astrocytes during ischemic stroke remains largely unknown. Mouse astrocytes were treated with oxygen-glucose deprivation/reoxygenation (OGD/R) to establish the in vitro model. Glial fibrillary acidic protein, NDRG2, Wnt3a and β-catenin expression levels were detected by immunofluorescence staining and western blot analyses. Glucose metabolism was investigated by glucose uptake, lactate production, nicotinamide adenine dinucleotide phosphate hydrogen/nicotinamide adenine dinucleotide phosphate (NADPH/NADP+), ATP and glycolysis enzymes (HK2, PKM2 and lactate dehydrogenase A [LDHA]) levels. Ferroptosis was assessed via reactive oxygen species (ROS), glutathione (GSH), iron and ferroptosis-related markers (GPX4 and PTGS2) contents. Glycolysis enzymes and ferroptosis-related markers levels were measured via western blot. NDRG2 expression was elevated in OGD/R-induced astrocytes. NDRG2 overexpression aggravated OGD/R-induced loss of glucose metabolism through reducing glucose uptake, lactate production, NADPH/NADP+ and ATP levels. NDRG2 upregulation exacerbated OGD/R-caused reduction of glycolysis enzymes (HK2, PKM2 and LDHA) levels. NDRG2 promoted OGD/R-induced ferroptosis of astrocytes by increasing ROS, iron and PTGS2 levels and decreasing GSH and GPX4 levels. NDRG2 overexpression enhanced OGD/R-induced decrease of Wnt/β-catenin signaling activation by reducing Wnt3a and β-catenin expression. NDRG2 silencing played an opposite effect. Inhibition of Wnt/β-catenin signaling activation by IWR-1 attenuated the influences of NDRG2 knockdown on glucose metabolism, glycolysis enzymes levels and ferroptosis. These findings demonstrated that NDRG2 contributes to OGD/R-induced inhibition of glucose metabolism and promotion of ferroptosis in astrocytes through inhibiting Wnt/β-catenin signaling activation, which might be associated with ischemic stroke progression.

Low NDRG2, regulated by the MYC/MIZ-1 complex and methylation, predicts poor outcomes in DLBCL patients

Diffuse large B-cell lymphoma (DLBCL) represents the most common tumor in non-Hodgkin's lymphoma. N-Myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor highly expressed in healthy tissues but downregulated in many cancers. Although cell proliferation-related metabolism rewiring has been well characterized, less is known about the mechanism of metabolic changes with DLBCL. Herein, we investigated the expressions of NDRG2, MYC and Myc-interacting zinc finger protein 1 (MIZ-1) in seven human lymphoma (mostly DLBCLs) cell lines. NDRG2 expression was inversely correlated with the expressions of MYC and MIZ-1. Further, we explored the regulatory mechanism and biological functions underlying the lymphomagenesis involving NDRG2, MYC and MIZ-1. MYC and MIZ-1 promoted DLBCL cell proliferation, while NDRG2 induced apoptosis in LY8 cells. Moreover, NDRG2 methylation was reversed by the 5-Aza-2'-deoxycytidine (5-Aza-CDR) treatment, triggering the downregulation of MYC and inhibiting DLBCL cell survival. MYC interacts with NDRG2 to regulate energy metabolism associated with mTOR. Remarkably, supporting the biological significance, the converse correlation between NDRG2 and MYC was observed in human DLBCL tumor tissues (R = -0.557). Bioinformatics analysis further validated the association among NDRG2, MYC, MIZ-1, mTOR, and related metabolism genes. Additionally, NDRG2 (P = 0.001) and MYC (P < 0.001) were identified as promising prognostic biomarkers in DLBCL patients through survival analysis. Together, our data demonstrate that the MYC/MIZ-1 complex interplays with NDRG2 to influence the proliferation and apoptosis of DLBCL cells and show the characterizations of NDRG2, MYC and MIZ-1 for metabolism features and prediction prognosis in DLBCL.

CircCOL1A1 promotes proliferation, migration, and invasion of colorectal cancer (CRC) cells and glutamine metabolism through GLS1 up-regulation by sponging miR-214-3p

BACKGROUND

Circular ribose nucleic acids (circRNAs), an abundant type of noncoding RNAs, are widely expressed in eukaryotic cells and exert a significant impact on the initiation and progression of various disorders, including different types of cancer. However, the specific role of various circRNAs in colorectal cancer (CRC) pathology is still not fully understood.

METHODS

The initial step involved the use of quantitative reverse transcription polymerase chain reaction (RT-qPCR) to assess the expression levels of circRNAs and messenger RNA (mRNA) in CRC cell lines and tissues. Subsequently, functional analyses of circCOL1A1 knockdown were conducted in vitro and in vivo through cell counting kit (CCK)-8, colony formation and transwell assays, as well as xenograft mouse model of tumor formation. Molecular expression and interactions were investigated using luciferase reporter assays, Western blot analysis, RNA immunoprecipitation (RIP), and immunohistochemical staining.

RESULTS

The RT-qPCR results revealed elevated levels of circCOL1A1 expressions in CRC tissues and cell lines as compared to the normal counterparts. In addition, circCOL1A1 expression level was found to be correlated with TNM stage, lymph node metastases, distant metastases, and invasion. Knockdown of circCOL1A1 resulted in impaired invasion, migration, and proliferation of CRC cells, and suppressed tumor generation in the animal model. We further demonstrated that circCOL1A1 could act as a sponge for miR-214-3p, suppressing miR-214-3p activity and leading to the upregulation of GLS1 protein to promote glutamine metabolism.

CONCLUSION

These findings suggest that circCOL1A1 functions as an oncogenic molecule to promote CRC progression via miR-214-3p/GLS1 axis, hinting on the potential of circCOL1A1 as a therapeutic target for CRC.

Metabolic subtypes and immune landscapes in esophageal squamous cell carcinoma: prognostic implications and potential for personalized therapies

BACKGROUND

This study aimed to identify metabolic subtypes in ESCA, explore their relationship with immune landscapes, and establish a metabolic index for accurate prognosis assessment.

METHODS

Clinical, SNP, and RNA-seq data were collected from 80 ESCA patients from the TCGA database and RNA-seq data from the GSE19417 dataset. Metabolic genes associated with overall survival (OS) and progression-free survival (PFS) were selected, and k-means clustering was performed. Immune-related pathways, immune infiltration, and response to immunotherapy were predicted using bioinformatic algorithms. Weighted gene co-expression network analysis (WGCNA) was conducted to identify metabolic genes associated with co-expression modules. Lastly, cell culture and functional analysis were performed using patient tissue samples and ESCA cell lines to verify the identified genes and their roles.

RESULTS

Molecular subtypes were identified based on the expression profiles of metabolic genes, and univariate survival analysis revealed 163 metabolic genes associated with ESCA prognosis. Consensus clustering analysis classified ESCA samples into three distinct subtypes, with MC1 showing the poorest prognosis and MC3 having the best prognosis. The subtypes also exhibited significant differences in immune cell infiltration, with MC3 showing the highest scores. Additionally, the MC3 subtype demonstrated the poorest response to immunotherapy, while the MC1 subtype was the most sensitive. WGCNA analysis identified gene modules associated with the metabolic index, with SLC5A1, NT5DC4, and MTHFD2 emerging as prognostic markers. Gene and protein expression analysis validated the upregulation of MTHFD2 in ESCA. MTHFD2 promotes the progression of ESCA and may be a potential therapeutic target for ESCA.

CONCLUSION

The established metabolic index and identified metabolic genes offer potential for prognostic assessment and personalized therapeutic interventions for ESCA, underscoring the importance of targeting metabolism-immune interactions in ESCA. MTHFD2 promotes the progression of ESCA and may be a potential therapeutic target for ESCA.

Comprehensive analysis of the role of ubiquitin-specific peptidases in colorectal cancer: A systematic review

BACKGROUND

Colorectal cancer (CRC) is the third most frequent and the second most fatal cancer. The search for more effective drugs to treat this disease is ongoing. A better understanding of the mechanisms of CRC development and progression may reveal new therapeutic strategies. Ubiquitin-specific peptidases (USPs), the largest group of the deubiquitinase protein family, have long been implicated in various cancers. There have been numerous studies on the role of USPs in CRC; however, a comprehensive view of this role is lacking.

AIM

To provide a systematic review of the studies investigating the roles and functions of USPs in CRC.

METHODS

We systematically queried the MEDLINE (via PubMed), Scopus, and Web of Science databases.

RESULTS

Our study highlights the pivotal role of various USPs in several processes implicated in CRC: Regulation of the cell cycle, apoptosis, cancer stemness, epithelial-mesenchymal transition, metastasis, DNA repair, and drug resistance. The findings of this study suggest that USPs have great potential as drug targets and noninvasive biomarkers in CRC. The dysregulation of USPs in CRC contributes to drug resistance through multiple mechanisms.

CONCLUSION

Targeting specific USPs involved in drug resistance pathways could provide a novel therapeutic strategy for overcoming resistance to current treatment regimens in CRC.

Ionizing radiation-induced mitophagy promotes ferroptosis by increasing intracellular free fatty acids

Ferroptosis is a type of cell death characterized by the accumulation of intracellular iron and an increase in hazardous lipid peroxides. Ferroptosis and autophagy are closely related. Ionizing radiation is a frequently used cancer therapy to kill malignancies. We found that ionizing radiation induces both ferroptosis and autophagy and that there is a form of mutualism between the two processes. Ionizing radiation also causes lipid droplets to form in proximity to damaged mitochondria, which, through the action of mitophagy, results in the degradation of the peridroplet mitochondria by lysosomes and the consequent release of free fatty acids and a significant increase in lipid peroxidation, thus promoting ferroptosis. Ionizing radiation has a stronger, fatal effect on cells with a high level of mitophagy, and this observation suggests a novel strategy for tumor treatment.

Impact of Opioids on Cellular Metabolism: Implications for Metabolic Pathways Involved in Cancer

Opioid utilization for pain management is prevalent among cancer patients. There is significant evidence describing the many effects of opioids on cancer development. Despite the pivotal role of metabolic reprogramming in facilitating cancer growth and metastasis, the specific impact of opioids on crucial oncogenic metabolic pathways remains inadequately investigated. This review provides an understanding of the current research on opioid-mediated changes to cellular metabolic pathways crucial for oncogenesis, including glycolysis, the tricarboxylic acid cycle, glutaminolysis, and oxidative phosphorylation (OXPHOS). The existing literature suggests that opioids affect energy production pathways via increasing intracellular glucose levels, increasing the production of lactic acid, and reducing ATP levels through impediment of OXPHOS. Opioids modulate pathways involved in redox balance which may allow cancer cells to overcome ROS-mediated apoptotic signaling. The majority of studies have been conducted in healthy tissue with a predominant focus on neuronal cells. To comprehensively understand the impact of opioids on metabolic pathways critical to cancer progression, research must extend beyond healthy tissue and encompass patient-derived cancer tissue, allowing for a better understanding in the context of the metabolic reprogramming already undergone by cancer cells. The current literature is limited by a lack of direct experimentation exploring opioid-induced changes to cancer metabolism as they relate to tumor growth and patient outcome.

The synergistic effect of IDH mutation and NDRG-2 dysregulation in the progression of WHO-grade 4 astrocytomas

BACKGROUND

NDRG2 is a tumour suppressor gene involved in tumor growth inhibition. Its effect on tumour recurrence remains controversial. The aim of this study is to explore the dual effect of IDH mutation and NDRG2 dysregulation in WHO-Grade 4 astrocytoma recurrence.

METHODS

A group of 36 patients with WHO-Grade 4 astrocytoma were examined for NDRG2 expression using protein and gene expression assays. The relationship between IDH, NDRG2 protein and gene expressions, and recurrence-free interval [RFI] was explored.

RESULTS

The mean patients age in this study was 45-years with 21 males and 15 females. IDH was mutant in 22 tumors. NDRG2 protein expression was low in 23 tumors, and high in 13 tumors. NDRG2 gene expression was upregulated in 4 tumors and 32 tumors showed NDRG2 gene downregulation. The consistency between two tasting methods of NDRG2 expression was 52.8%. There was a significant statistical difference in RFI among tumors with varying NDRG2 gene expression and IDH mutation [p-value= 0.021]. IDH-mutant tumours with downregulated NDRG2 expression showed late recurrence compared to IDH-wildtype glioblastoma.

CONCLUSIONS

IDH-mutant WHO Grade-4 astrocytoma with downregulated NDRG2 gene are associated with late tumor recurrence. IDH mutations cause excessive accumulation of D-2-hydroxyglutarate, that may inhibit the activity of TET proteins, potentially leading to DNA hypermethylation and gene silencing.

Re-Shaping the Pancreatic Cancer Tumor Microenvironment: A New Role for the Metastasis Suppressor NDRG1

Pancreatic cancer (PaC) is a highly aggressive disease, with poor response to current treatments and 5-year survival rates of 10-15%. PaC progression is facilitated by its interaction with the complex and multifaceted tumor microenvironment (TME). In the TME, cancer cells and surrounding stromal cells constantly communicate with each other via the secretion and uptake of factors including cytokines, chemokines, growth factors, metabolites, and extracellular vesicles (EVs), reshaping the landscape of PaC. Recent studies demonstrated that the metastasis suppressor N-myc downstream regulated 1 (NDRG1) not only inhibits oncogenic signaling pathways in PaC cells but also alters the communication between PaC cells and the surrounding stroma. In fact, NDRG1 was found to influence the secretome of PaC cells, alter cancer cell metabolism, and interfere with intracellular trafficking and intercellular communication between PaC cells and surrounding fibroblasts. This review will present recent advancements in understanding the role of NDRG1 in PaC progression, with a focus on how this molecule influences PaC-stroma communication and its potential for re-shaping the PaC TME.

Glutamine Starvation Affects Cell Cycle, Oxidative Homeostasis and Metabolism in Colorectal Cancer Cells

Cancer cells adjust their metabolism to meet energy demands. In particular, glutamine addiction represents a distinctive feature of several types of tumors, including colorectal cancer. In this study, four colorectal cancer cell lines (Caco-2, HCT116, HT29 and SW480) were cultured with or without glutamine. The growth and proliferation rate, colony-forming capacity, apoptosis, cell cycle, redox homeostasis and metabolomic analysis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT), flow cytometry, high-performance liquid chromatography and gas chromatography/mass spectrometry techniques. The results show that glutamine represents an important metabolite for cell growth and that its deprivation reduces the proliferation of colorectal cancer cells. Glutamine depletion induces cell death and cell cycle arrest in the GO/G1 phase by modulating energy metabolism, the amino acid content and antioxidant defenses. Moreover, the combined glutamine starvation with the glycolysis inhibitor 2-deoxy-D-glucose exerted a stronger cytotoxic effect. This study offers a strong rationale for targeting glutamine metabolism alone or in combination with glucose metabolism to achieve a therapeutic benefit in the treatment of colon cancer.

Correlation of Glucose Metabolism with Cancer and Intervention with Traditional Chinese Medicine

Cancer is a complex disease with several distinct characteristics, referred to as “cancer markers” one of which is metabolic reprogramming, which is a common feature that drives cancer progression. Over the last ten years, researchers have focused on the reprogramming of glucose metabolism in cancer. In cancer, the oxidative phosphorylation metabolic pathway is converted into the glycolytic pathway in order to meet the growth requirements of cancer cells, thereby creating a microenvironment that promotes cancer progression. The precise mechanism of glucose metabolism in cancer cells is still unknown, but it is thought to involve the aberrant levels of metabolic enzymes, the influence of the tumor microenvironment (TME), and the activation of tumor-promoting signaling pathways. It is suggested that glucose metabolism is strongly linked to cancer progression because it provides energy to cancer cells and interferes with antitumor drug pharmacodynamics. Therefore, it is critical to unravel the mechanism of glucose metabolism in tumors in order to gain a better understanding of tumorigenesis and to lay the groundwork for future research into the identification of novel diagnostic markers and therapeutic targets for cancer treatment. Traditional Chinese Medicine (TCM) has the characteristics of multiple targets, multiple components, and less toxic side effects and has unique advantages in tumor treatment. In recent years, researchers have found that a variety of Chinese medicine monomers and compound recipes play an antitumor role by interfering with the reprogramming of tumor metabolism. The underlying mechanisms of metabolism reprogramming of tumor cells and the role of TCM in regulating glucose metabolism are reviewed in this study, so as to provide a new idea for antitumor research in Chinese medicine.

ERN1 dependent impact of glutamine and glucose deprivations on the pyruvate dehydrogenase genes expression in glioma cells

Objective. The aim of the present study was to investigate the expression of pyruvate dehydrogenase genes such as PDHA1, PDHB, DLAT, DLD, and PDHX in U87 glioma cells in response to glutamine and glucose deprivations in control glioma cells and endoplasmic reticulum to nucleus signaling 1 (ERN1) knockdown cells, the major endoplasmic reticulum (ER) stress signaling pathway, to find out whether there exists a possible dependence of these important regulatory genes expression on both glutamine and glucose supply as well as ERN1 signaling.

Methods. The expression level of PDHA1, PDHB, DLAT, DLD, and PDHX genes was studied by real-time quantitative polymerase chain reaction in control U87 glioma cells (transfected by empty vector) and cells with inhibition of ERN1(transfected by dnERN1) after cells exposure to glucose and glutamine deprivations.

Results. The data showed that the expression level of PDHA1, PDHB, DLAT, and DLD genes was down-regulated (more profound in PDHB gene) in control glioma cells treated with glutamine deprivation. At the same time, ERN1 knockdown modified the impact of glutamine deprivation on the expression level of all these genes in glioma cells: suppressed the sensitivity of PDHB and DLD genes expression and removed the impact of glutamine deprivation on the expression of PDHA1 and DLAT genes. Glucose deprivation did not significantly change the expression level of all studied genes in control glioma cells, but ERN1 knockdown is suppressed the impact of glucose deprivation on PDHX and DLD genes expression and significantly enhanced the expression of PDHA1 and PDHB genes. No significant changes were observed in the sensitivity of PDHX gene expression to glutamine deprivation neither in control nor ERN1 knock-down glioma cells. The knock-down of ERN1 removed the sensitivity of DLAT gene expression to glucose deprivation.

Conclusion. The results of this investigation demonstrate that the exposure of control U87 glioma cells under glutamine deprivation significantly affected the expression of PDHA1, PDHB, DLAT, and DLD genes in a gene specific manner and that impact of glutamine deprivation was modified by inhibition of the ER stress signaling mediated by ERN1. At the same time, glucose deprivation affected the expression of PDHA1, PDHB, PDHX, and DLD genes in ERN1 knockdown glioma cells only. Thus, the expression of pyruvate dehydrogenase genes under glutamine and glucose deprivation conditions appears to be controlled by the ER stress signaling through ERN1.

NDRG2 inhibits pyruvate carboxylase-mediated anaplerosis and combines with glutamine blockade to inhibit the proliferation of glioma cells

Due to the rapid proliferation, cancer cells have increased anabolic biosynthesis, which requires anaplerosis to replenish precursor intermediates. The major anaplerotic sources are pyruvate and glutamine, which require the catalysis of pyruvate carboxylase (PC) and glutaminase (GLS) respectively. In GLS-suppressed cancer cells, the PC-mediated pathway for anaplerosis is crucial to maintain cell growth and proliferation. Here, we investigated the regulatory role and molecular mechanism of N-myc downstream-regulated gene 2 (NDRG2) in PC and PC-mediated anaplerosis. NDRG2 interacted with PC and induced the degradation of PC in glutamine-deprived cells. NDRG2 also inhibited the activity of PC and PC-mediated anaplerosis. As a result, NDRG2 significantly inhibited the malignant growth and proliferation of glioma cells in combination with a glutamine antagonist. In addition, NDRG2 more significantly inhibited the protein level of PC in isocitrate dehydrogenase 1 (R132H)-mutant glioma cells than in wild-type glioma cells. These findings indicate that the molecular mechanism of NDRG2 inhibits PC-mediated anaplerosis and collaborates with glutamine antagonist to inhibit the malignant proliferation of glioma cells, thus providing a theoretical and experimental basis for targeting anaplerosis in glioma therapy.

The role of endoplasmic reticulum stress in the regulation of long noncoding RNAs in cancer

Cancer cells must overcome a variety of external and internal stresses to survive and proliferate. These unfavorable conditions include the accumulation of mutations, nutrient deficiency, oxidative stress, and hypoxia. These stresses can cause aggregation of misfolded proteins inside the endoplasmic reticulum. Under these conditions, the cell undergoes endoplasmic reticulum stress (ER-stress), and consequently initiates the unfolded protein response (UPR). Activation of the UPR triggers transcription factors and regulatory factors, including long noncoding RNAs (lncRNAs), which control the gene expression profile to maintain cellular stability and hemostasis. Recent investigations have shown that cancer cells can ensure their survival under adverse conditions by the UPR affecting the expression of lncRNAs. Therefore, understanding the relationship between lncRNA expression and ER stress could open new avenues, and suggest potential therapies to treat various types of cancer.

Colorectal Cancer Cell Differentiation Is Dependent on the Repression of Aerobic Glycolysis by NDRG2-TXNIP Axis

BACKGROUND

Poorly differentiated colorectal cancers are more aggressive. Metabolism reprogramming is a significant hallmark in cancer, and aerobic glycolysis is common. However, how cancer cells reprogramming glucose metabolism contributes to cell differentiation was largely unknown. Previous studies have reported that tumor suppressor NDRG2 could promote colorectal cancers differentiation.

AIMS

This study aims to demonstrate that NDRG2 promotes the differentiation of colorectal cancers, potentially through the inhibition of aerobic glycolysis via TXNIP induction.

METHODS

Western blotting, qRT-PCR and immunohistochemical staining were used to detect the expression of related molecules. MTT assay was used to reflect cell viability and proliferation. Immunofluorescent assay was performed to identify the expression and distribution of molecules. Luciferase analysis and CHIP assays were used to investigate the mechanism. Bioinformatic analysis was performed to predict the relevance.

RESULTS

In colorectal cancers, NDRG2 could inhibit cell proliferation, reduce glucose uptake and decrease expression of key glycolysis enzymes. Upregulated NDRG2 is associated with differentiated cancer. However, deletion of TXNIP, a classic glucose metabolism inhibitor, could obviously alter the function of NDRG2 in differentiation, glucose uptake, expression of key glycolysis enzymes and proliferation. Mechanistically, high glucose flux promotes the activity of TXNIP promoter. And NDRG2 promotes the occupancy of transcription factor Mondo A on TXNIP promoter, predominantly through the suppression of c-myc, which could complete with Mondo A binding to TXNIP promoter. In clinical samples, high expression of TXNIP indicates good prognosis and outcome.

CONCLUSIONS

NDRG2-dependent induction of TXNIP is critical for the aerobic glycolysis during colorectal cancers differentiation.

GLS1 is a protective factor in patients with ovarian clear cell carcinoma and its expression does not correlate with ARID1A-mutated tumors

Targeting glutamine metabolism has emerged as a novel therapeutic strategy for several human cancers, including ovarian cancer. The primary target of this approach is the kidney isoform of glutaminase, glutaminase 1 (GLS1), a key enzyme in glutamine metabolism that is overexpressed in several human cancers. A first-in-class inhibitor of GLS1, called CB839 (Telaglenastat), has been investigated in several clinical trials, with promising results. The first clinical trial of CB839 in platinum-resistant ovarian cancer patients is forthcoming. ARID1A-mutated ovarian clear cell carcinoma (OCCC) is a relatively indolent and chemoresistant ovarian cancer histotype. In OCCC-derived cells ARID1A simultaneously drives GLS1 expression and metabolism reprograming. In ARID1A-mutated OCCC-derived mouse models, loss of ARID1A corresponds to GLS1 upregulation and increases sensitivity to GLS1 inhibition. Thus, targeting of GLS1 with CB839 has been suggested as a targeted approach for OCCC patients with tumors harboring ARID1A-mutations. Here, we investigated whether GLS1 is differentially expressed between OCCC patients whose tumors are ARID1A positive and patients whose tumors are ARID1A negative. In clinical specimens of OCCC, we found that GLS1 overexpression was not correlated with ARID1A loss. In addition, GLS1 overexpression was associated with better clinical outcomes. Our findings have implications for human trials using experimental therapeutics targeting GLS1.

Fructose-1,6-Bisphosphatase 2 Inhibits Oral Squamous Cell Carcinoma Tumorigenesis and Glucose Metabolism via Downregulation of c-Myc

Background

Fructose-1,6-bisphosphatase 2 (FBP2), known as a rate-limiting enzyme in gluconeogenesis, is a tumor suppressor downregulated in various cancers. However, the role of FBP2 in oral squamous cell carcinoma (OSCC) remains largely unclear.

Methods

The level of FBP2 in OSCC tissues and matched adjacent normal tissues was determined by western blot and RT-qPCR assays. In addition, analysis of FBP2 function in OSCC cells was assessed using both gain-of-function and loss-of-function studies.

Results

In this study, we found that the expression of FBP2 was remarkably downregulated in OSCC tissues and OSCC cells. Overexpression of FBP2 suppressed the viability, proliferation, migration, and glycolysis of OSCC cells, whereas FBP2 knockdown exhibited the opposite results. Moreover, downregulation of FBP2 promoted the growth and glycolysis of OSCC cells in nude mice in a xenograft model. Specifically, FBP2 colocalizes with the c-Myc transcription factor in the nucleus. Significantly, inhibitory effects of FBP2 overexpression on the viability, proliferation, migration, and glycolysis of OSCC cells were reversed by c-Myc overexpression.

Conclusion

Collectively, FBP2 could suppress the proliferation, migration and glycolysis in OSCC cells through downregulation of c-Myc. Our study revealed a FBP2-c-Myc signaling axis that regulates OSCC glycolysis and may provide a potential intervention strategy for OSCC treatment.

Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers

N-Myc downstream regulated gene 3 (NDRG3) is a unique pro-tumorigenic member among NDRG family genes, mediating growth signals. Here, we investigated the pathophysiological roles of NDRG3 in relation to cell metabolism by disrupting its functions in liver. Mice with liver-specific KO of NDRG3 (Ndrg3 LKO) exhibited glycogen storage disease (GSD) phenotypes including excessive hepatic glycogen accumulation, hypoglycemia, elevated liver triglyceride content, and several signs of liver injury. They suffered from impaired hepatic glucose homeostasis, due to the suppression of fasting-associated glycogenolysis and gluconeogenesis. Consistently, the expression of glycogen phosphorylase (PYGL) and glucose-6-phosphate transporter (G6PT) was significantly down-regulated in an Ndrg3 LKO-dependent manner. Transcriptomic and metabolomic analyses revealed that NDRG3 depletion significantly perturbed the methionine cycle, redirecting its flux towards branch pathways to upregulate several metabolites known to have hepatoprotective functions. Mechanistically, Ndrg3 LKO-dependent downregulation of glycine N-methyltransferase in the methionine cycle and the resultant elevation of the S-adenosylmethionine level appears to play a critical role in the restructuring of the methionine metabolism, eventually leading to the manifestation of GSD phenotypes in Ndrg3 LKO mice. Our results indicate that NDRG3 is required for the homeostasis of liver cell metabolism upstream of the glucose–glycogen flux and methionine cycle and suggest therapeutic values for regulating NDRG3 in disorders with malfunctions in these pathways.

MiR-181a-5p facilitates proliferation, invasion, and glycolysis of breast cancer through NDRG2-mediated activation of PTEN/AKT pathway

Dysregulation of microRNAs (miRNAs) is associated with the occurrence and development of breast cancer. In this research, we explored the involvement of miR-181a-5p in the progression of breast cancer and investigated potential molecular mechanisms. Firstly, the miR-181a-5p and N-myc downstream-regulated gene (NDRG) 2 expression was detected by real-time quantitative polymerase chain reaction. Cellular processes were assessed using Cell Counting Kit 8, Bromodeoxyuridine, colony formation and transwell assays. HK2, PKM2 and LDHA activities were assessed by ELISA. The combination between miR-181a-5p was assessed by dual-luciferase reporter assay and RNA pull-down assay. The results indicated that miR-181a-5p levels were upregulated and NDRG2 levels were downregulated in breast cancer, leading to poor prognosis. Silencing of miR-181a-5p inhibited cell proliferation, invasion, glycolysis, and xenograft tumor growth, while enhanced miR-181a-5p got the opposite results. Furthermore, NDRG2 acts as a target of miR-181a-5p. Knockout of NDRG2 facilitated biological behaviors and meanwhile enhanced phosphorylation (p)-PTEN and p-AKT levels. Rescue experiments showed that restoring NDRG2 abolished the effects caused by miR-181a-5p in breast cancer cells. In conclusion, miR-181a-5p facilitated tumor progression through NDRG2-induced activation of PTEN/AKT signaling pathway of breast cancer, suggesting that focusing on miR-181a-5p may provide new insight for breast cancer therapy.

Abbreviations Brdu: Bromodeoxyuridine; CCK-8: Cell Counting Kit-8; miRNA: microRNAs; mut: mutant; RT-qPCR: real-time quantitative polymerase chain reaction; UTR: untranslated region; WT: wild-type

The Crosstalk Between Signaling Pathways and Cancer Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Metabolic reprogramming represents an important cancer hallmark in CRC. Reprogramming core metabolic pathways in cancer cells, such as glycolysis, glutaminolysis, oxidative phosphorylation, and lipid metabolism, is essential to increase energy production and biosynthesis of precursors required to support tumor initiation and progression. Accumulating evidence demonstrates that activation of oncogenes and loss of tumor suppressor genes regulate metabolic reprogramming through the downstream signaling pathways. Protein kinases, such as AKT and c-MYC, are the integral components that facilitate the crosstalk between signaling pathways and metabolic pathways in CRC. This review provides an insight into the crosstalk between signaling pathways and metabolic reprogramming in CRC. Targeting CRC metabolism could open a new avenue for developing CRC therapy by discovering metabolic inhibitors and repurposing protein kinase inhibitors/monoclonal antibodies.

N-myc Downstream-Regulated Gene 2 (NDRG2) Function as a Positive Regulator of Apoptosis: A New Insight into NDRG2 as a Tumor Suppressor

N-myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor gene that increases tumor sensitivity to anticancer drugs, slows tumor progression, and inhibits metastasis. NDRG2 is suppressed in various aggressive tumor positions, whereas NDRG2 expression is associated with patient prognosis, such as an improved survival rate. In this review, we summarize the tumor suppressor mechanism of NDRG2 and provide information on the function of NDRG2 concerning the susceptibility of cells to apoptosis. NDRG2 increases the susceptibility to apoptosis in various physiological environments of cells, such as development, hypoxia, nutrient deprivation, and cancer drug treatment. Although the molecular and cell biological mechanisms of NDRG2 have not been fully elucidated, we provide information on the mechanisms of NDRG2 in relation to apoptosis in various environments. This review can assist the design of research regarding NDRG2 function and suggests the potential of NDRG2 as a molecular target for cancer patients.

Interplay between Epigenetics and Cellular Metabolism in Colorectal Cancer

Cellular metabolism alterations have been recognized as one of the most predominant hallmarks of colorectal cancers (CRCs). It is precisely regulated by many oncogenic signaling pathways in all kinds of regulatory levels, including transcriptional, post-transcriptional, translational and post-translational levels. Among these regulatory factors, epigenetics play an essential role in the modulation of cellular metabolism. On the one hand, epigenetics can regulate cellular metabolism via directly controlling the transcription of genes encoding metabolic enzymes of transporters. On the other hand, epigenetics can regulate major transcriptional factors and signaling pathways that control the transcription of genes encoding metabolic enzymes or transporters, or affecting the translation, activation, stabilization, or translocation of metabolic enzymes or transporters. Interestingly, epigenetics can also be controlled by cellular metabolism. Metabolites not only directly influence epigenetic processes, but also affect the activity of epigenetic enzymes. Actually, both cellular metabolism pathways and epigenetic processes are controlled by enzymes. They are highly intertwined and are essential for oncogenesis and tumor development of CRCs. Therefore, they are potential therapeutic targets for the treatment of CRCs. In recent years, both epigenetic and metabolism inhibitors are studied for clinical use to treat CRCs. In this review, we depict the interplay between epigenetics and cellular metabolism in CRCs and summarize the underlying molecular mechanisms and their potential applications for clinical therapy.

N-myc downstream regulated gene 2 ameliorates myocardial remodeling and cardiac function in heart failure rats

This study aims to explore the effect of NDRG2 (N-myc downstream regulated gene 2)-mediated Transforming growth factor-beta 1 (TGF-β1)/ Sma- and Mad-related protein (Smad) pathway in heart failure (HF) rats. HF rat models were established and treated with AdEGFP (adenovirus encoding enhanced green fluorescent protein) or AdNDRG2 (adenovirus encoding NDRG2). The echocardiography and hemodynamic parameters were detected, and the infarct size was calculated via 2,3,5-triphenyltetrazolium chloride (TTC) staining. Masson staining was performed to observe the collagen volume fraction (CVF), quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) to detect the expression of Collagen I (Col-I) and Collagen III (Col-III), and Transferase (TdT)-mediated D-UTP-biotin nick end labeling (TUNEL) staining to evaluate the apoptosis. Rats in the Model group presented with the decreases in left ventricular ejection fraction (LVEF), left ventricular shortening fraction (LVFS), left ventricular systolic pressure (LVSP) and maximal/minimum rate of left ventricular pressure (±dp/dt max), and significant increases in left ventricular end-diastolic pressure (LVEDP) and CVF. At the meantime, the expression of Col-I and Col-III as well as the apoptotic rate of myocardial cells was also elevated with increased infarct size in the Model group. The Model rats also had the significant reduction in the expression of NDRG2 and up-regulations of TGF-β1, p-Smad2/Smad2, p-Smad3/Smad3 and tissue inhibitor of metalloproteinases-2 (TIMP-2). However, model rats treated with AdNDRG2 had evident amelioration in aforementioned indicators. In conclusion, NDRG2 reduces the apoptosis of myocardial cells and improves the heart function and myocardial remodeling in HF rats via inhibiting the activity of TGF-β1/Smad.

The Role of N-myc Downstream-Regulated Gene Family in Glioma Based on Bioinformatics Analysis

Glioma is the most common type of primary tumor in the central nervous system, and the molecular mechanisms remain elusive. N-myc downstream-regulated gene (NDRG) family is reported to take part in the pathogenesis of various diseases, including some preliminary exploration in glioma. However, there has been no bioinformatics analysis of NDRG family in glioma yet. Herein, we focused on the expression changes of NDRGs with their value in predicting patients' prognoses, upstream regulatory mechanisms (DNA mutation, DNA methylation, transcription factors, and microRNA regulation) and gene enrichment analysis based on co-expressed genes with data from public databases. Furthermore, the expression pattern of NDRGs was verified by the paired glioma and peritumoral samples in our institute. It was suggested that NDRGs were differentially expressed genes in glioma. In particular, the lower expression of NDRG2 or NDRG4 could serve as a predictor of higher grade tumor and poorer prognosis. Also, NDRGs might play a crucial role in signal transduction, energy metabolism, and cross-talk among cells in glioma, under the control of a complex regulatory network. This study enables us to better understand the role of NDRGs in glioma and with further research, it may contribute to the development of glioma treatment.

Targeting GLS1 to cancer therapy through glutamine metabolism

Glutamine metabolism is one of the hallmarks of cancers which is described as an essential role in serving as a major energy and building blocks supply to cell proliferation in cancer cells. Many malignant tumor cells always display glutamine addiction. The "kidney-type" glutaminase (GLS1) is a metabolism enzyme which plays a significant part in glutaminolysis. Interestingly, GLS1 is often overexpressed in highly proliferative cancer cells to fulfill enhanced glutamine demand. So far, GLS1 has been proved to be a significant target during the carcinogenesis process, and emerging evidence reveals that its inhibitors could provide a benefit strategy for cancer therapy. Herein, we summarize the prognostic value of GLS1 in multiple cancer type and its related regulatory factors which are associated with antitumor activity. Moreover, this review article highlights the remarkable reform of discovery and development for GLS1 inhibitors. On the basis of case studies, our perspectives for targeting GLS1 and development of GLS1 antagonist are discussed in the final part.

Blockage of glioma cell survival by truncated TEAD-binding domain of YAP

BACKGROUND

Gliomas are highly aggressive and lack of efficient targeted therapy. YAP, as a Hippo pathway downstream effector, plays a key role in promoting tumor development through the interaction with transcription factor TEAD on the NH3-terminal proline-rich domain. Therefore, targeting TEAD-interacting domain of YAP may provide a novel approach for the treatment of gliomas.

MATERIALS AND METHODS

We generated a truncated YAP protein which includes the TEAD-binding domain (YAPBD), and supposed YAPBD can interact with endogenous TEAD but lost the function to activate YAP target gene expressions. The association of YAP expression with the malignant characters of glioma tissues were determined by immunohistochemistry. TEAD-binding capacity of YAPBD was determined by co-immunoprecipitation. The cell proliferation and migration were determined by MTT assay, xenograft assay, wound healing assay and transwell assay, respectively. YAP target genes were detected by Western blot.

RESULTS

YAP was highly expressed in glioma tissues and associated with tumor malignancy. YAPBD could block the TEAD-YAP complex formation by competing with YAP binding to TEAD. YAPBD could inhibit glioma cell growth both in vitro and in vivo, through the induction of cell cycle arrest and apoptosis. The cell cycle-related gene cyclin D1 and c-myc, and anti-apoptotic gene Bcl-2, Bcl-xL and survivin were inhibited after YAPBD overexpression. Furthermore, YAPBD also decreased cell migration and invasion, and repressed epithelial-mesenchymal transition.

CONCLUSION

YAPBD can block glioma cell survival and repress YAP-dependent gene expressions, indicating gene therapy which targets TEAD-YAP complex would be a potential and significant novel approach for human malignant gliomas.

LncRNA RAD51-AS1/miR-29b/c-3p/NDRG2 crosstalk repressed proliferation, invasion and glycolysis of colorectal cancer

LncRNAs are recently increasingly emerging as molecules that take its part in human carcinogenesis. A large body of literature has identified the functional roles of lncRNAs in the pathophysiology of CRC. The current study was intended to provide new ideas and perspectives for the functional role of lncRNA RAD51-AS1 in regulating CRC progression. Herein, a survey of RAD51-AS1 expression profile in The Cancer Genome Atlas (TCGA)-colon adenocarcinoma (COAD) dataset revealed that RAD51-AS1 was downregulated in COAD specimens. Consistently, RAD51-AS1 expression was observed to be lower in CRC cell lines compared with normal cell line (NCM460). In the meanwhile, both the levels of miR-29b-3p and miR-29c-3p were prominently elevated in CRC cells. Functionally, administration of RAD51-AS1 refrained growth, invasion and migration of CRC cells. Additionally, accumulation of RAD51-AS1 hampered glucose consumption and lactate production, as well as the restraint of hexokinase 2 (HK2) and glucose transporter 1 (GLUT1) levels. More important, RAD51-AS1 functioned as a competing endogenous RNA (ceRNA) for sponging miR-29b-3p and miR-29c-3p, leading to enhancement of their common target N-myc downstream-regulated gene 2 (NDRG2). Mechanistically, the delivery of miR-29b/c-3p mimics or ablation of NDRG2 effectively blunted the salutary effects of RAD51-AS1 on CRC cell behaviors. Moreover, augmentation of RAD51-AS1 inhibited the tumorigenesis of CRC cells in vivo. Collectively, these findings provide comprehensive evidence that RAD51-AS1 repressed cell proliferation, migration, invasion and glycolysis process, ultimately contributing to the progression of CRC by repressing the miR-29b/c-3p/NDRG2 signaling axis, insinuating the putative potential of RAD51-AS1/miR-29b/c-3p/NDRG2 interaction network in unraveling CRC pathology and hopefully contributed to the treatment of CRC patients.

MicroRNA-122 regulates docetaxel resistance of prostate cancer cells by regulating

Prostate cancer (PCa), an epithelial malignancy that occurs in the prostate, is the second leading cause of cancer death worldwide. MicroRNAs (miRs/miRNAs) are reported to have important applications in the field of cancer diagnosis and treatment. The present study aimed to investigate the function of miRNA-122 in the chemoresistance of PCa cells and the underlying mechanism. Significantly decreased miR-122 and increased pyruvate kinase (PKM2) levels were observed in docetaxel-resistant PCa cells, and PKM2 was negatively correlated with miR-122. MiR-122 mimic transfection in docetaxel-resistant LNCaP cells significantly inhibited cell proliferation, promoted apoptosis and decreased glucose uptake and lactate production, which was counteracted by PKM2 overexpression. Inhibition of miR-122 in LNCaP cells had an opposite effect to miR-122 mimic transfection. In addition, miR-122 mimic transfection significantly increased the sensitivity of docetaxel-resistant LNCaP cells to docetaxel, while inhibition of miR-122 significantly decreased the sensitivity of LNCaP cells to docetaxel. Luciferase reporter assays showed that miR-122 regulated PKM2 expression by binding to the 3'-untranslated region of PKM2. The results suggest that upregulation of miR-122 could enhance docetaxel sensitivity, inhibit cell proliferation and promote apoptosis in PCa cells,possibly through the downregulation of its target protein PKM2.

NDRG2 ablation reprograms metastatic cancer cells towards glutamine dependence via the induction of ASCT2

Background: Metastasis is the most common cause of lethal outcome in various types of cancers. Although the cell proliferation related metabolism rewiring has been well characterized, less is known about the association of metabolic changes with tumor metastasis. Herein, we demonstrate that metastatic tumor obtained a mesenchymal phenotype, which is obtained by the loss of tumor suppressor NDRG2 triggered metabolic switch to glutamine metabolism.

Methods: mRNA-seq and gene expression profile analysis were performed to define the differential gene expressions in primary MEC1 and metastatic MC3 cells and the downstream pathways of NDRG2. NDRG2 regulation of Fbw7-dependent c-Myc stability were determined by immunoprecipitation and protein half-life assay. Luciferase reporter and ChIP assays were used to determine the roles of Akt and c-Myc in mediating NDRG2-dependent regulation of ASCT2 in in both tumor and NDRG2-knockout MEF cells. Finally, the effect of the NDRG2/Akt/c-Myc/ASCT2 signaling on glutaminolysis and tumor metastasis were evaluated by functional experiments and clinical samples.

Results: Based on the gene expression profile analysis, we identified metastatic tumor cells acquired the mesenchymal-like characteristics and displayed the increased dependency on glutamine utilization. Further, the gain of NDRG2 function blocked epithelial-mesenchymal transition (EMT) and glutaminolysis, potentially through suppression of glutamine transporter ASCT2 expression. The ASCT2 restoration reversed NDRG2 inhibitory effect on EMT program and tumor metastasis. Mechanistic study indicates that NDRG2 promoted Fbw7-dependent c-Myc degradation by inhibiting Akt activation, and subsequently decreased c-Myc-mediated ASCT2 transcription, in both tumor and NDRG2-knockout MEF cells. Supporting the biological significance, the reciprocal relationship between NDRG2 and ASCT2 were observed in multiple types of tumor tissues, and associated with tumor malignancy.

Conclusions: NDRG2-dependent repression of ASCT2 presumably is the predominant route by which NDRG2 rewires glutaminolysis and blocks metastatic tumor survival. Targeting glutaminolytic pathway may provide a new strategy for the treatment of metastatic tumors.

Low NDRG2 expression predicts poor prognosis in solid tumors: A meta-analysis of cohort study

BACKGROUND

As a member of the N-myc down-regulated gene family, N-Myc downstream-regulated gene 2 (NDRG2) contributes to the tumorigenesis of various types of cancers. However, the correlation between NDRG2 expression and the prognosis of solid tumor remains to be elucidated because of small sample sizes and inconsistent results in previous studies. In the present study, we conducted a systematic review and meta-analysis to explore the prognostic significance of NDRG2 in human solid tumors.

METHODS

PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure, and WanFang databases (up to April 2020) were searched for relevant studies that evaluated the impact of NDRG2 on clinical outcomes, including overall survival (OS), and disease-free survival (DFS), in solid tumors. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled to assess the association between NDRG2 expression and the survival of patients with solid tumors. Odds ratios (ORs) with 95% CIs were pooled to estimate the correlation between NDRG2 expression and clinicopathologic characteristics in the patients.

RESULTS

A total of 13 eligible studies with 1980 patients were included in this meta-analysis. Low NDRG2 expression was significantly associated with poor OS (HR = 1.96, 95% CI: 1.60-2.40, P < .001) and DFS (HR = 2.70, 95% CI: 1.42-5.13, P = .002) in solid tumor. Furthermore, low NDRG2 expression was related to some phenotypes of tumor aggressiveness, such as clinical stage (OR = 3.21, 95% CI: 1.96-5.26, P < .001), lymph node metastasis (OR = 2.14, 95% CI: 1.49-3.07, P < .001), and degree of differentiation (OR = 0.60, 95% CI: 0.45-0.81, P = .001).

CONCLUSIONS

NDRG2 may be a meaningful biomarker of poor prognosis and a potential therapeutic target for human solid tumors.

NCTD elicits proapoptotic and antiglycolytic effects on colorectal cancer cells via modulation of Fam46c expression and inhibition of ERK1/2 signaling

Colorectal cancer is a digestive tract malignancy and the third leading cause of cancer‑related mortality worldwide. Norcantharidin (NCTD), the demethylated form of cantharidin, has been reported to possess anticancer properties. Family‑with‑sequence‑similarity‑46c (Fam46c), a non‑canonical poly(A) polymerase, has been reported to be critical in NCTD‑mediated effects in numerous types of cancer, including hepatoma. In the current study, it was found that Fam46c expression was reduced in colorectal cancer tissues and cells. Treatment with NCTD was observed to significantly enhance apoptosis and inhibit glycolysis in colorectal cancer cells. In addition, Fam46c and cleaved caspase 3 expression levels were found to be increased in response to NCTD treatment, in contrast to tumor‑specific pyruvate kinase M2 and phosphorylated ERK expression, which was reduced. Importantly, overexpression of Fam46c exerted similar effects as NCTD treatment on the apoptosis and glycolysis of colorectal cancer cells, whereas Fam46c knockdown strongly attenuated the effect of NCTD. Moreover, epidermal growth factor, which acts as an agonist of ERK1/2 signaling, weakened the effects of NCTD on colorectal cancer cells. Taken together, the results indicated that NCTD promotes apoptosis and suppresses glycolysis in colorectal cancer cells by possibly targeting Fam46c and inhibiting ERK1/2 signaling, hence suggesting that Fam46c may act as a tumor suppressor in colorectal cancer. Thus, the present study identified a novel therapeutic target of NCTD in the clinical treatment of colorectal cancer.

Targeting Altered Energy Metabolism in Colorectal Cancer: Oncogenic Reprogramming, the Central Role of the TCA Cycle and Therapeutic Opportunities

Colorectal cancer (CRC) is among the most frequent cancer entities worldwide. Multiple factors are causally associated with CRC development, such as genetic and epigenetic alterations, inflammatory bowel disease, lifestyle and dietary factors. During malignant transformation, the cellular energy metabolism is reprogrammed in order to promote cancer cell growth and proliferation. In this review, we first describe the main alterations of the energy metabolism found in CRC, revealing the critical impact of oncogenic signaling and driver mutations in key metabolic enzymes. Then, the central role of mitochondria and the tricarboxylic acid (TCA) cycle in this process is highlighted, also considering the metabolic crosstalk between tumor and stromal cells in the tumor microenvironment. The identified cancer-specific metabolic transformations provided new therapeutic targets for the development of small molecule inhibitors. Promising agents are in clinical trials and are directed against enzymes of the TCA cycle, including isocitrate dehydrogenase, pyruvate dehydrogenase kinase, pyruvate dehydrogenase complex (PDC) and α-ketoglutarate dehydrogenase (KGDH). Finally, we focus on the α-lipoic acid derivative CPI-613, an inhibitor of both PDC and KGDH, and delineate its anti-tumor effects for targeted therapy.

Molecular dissection of Chagas induced cardiomyopathy reveals central disease associated and druggable signaling pathways

Chagas disease, the clinical presentation of T. cruzi infection, is a major human health concern. While the acute phase of Chagas disease is typically asymptomatic and self-resolving, chronically infected individuals suffer numerous sequelae later in life. Cardiomyopathies in particular are the most severe consequence of chronic Chagas disease and cannot be reversed solely by parasite load reduction. To prioritize new therapeutic targets, we unbiasedly interrogated the host signaling events in heart tissues isolated from a Chagas disease mouse model using quantitative, multiplexed proteomics. We defined the host response to infection at both the proteome and phospho-proteome levels. The proteome showed an increase in the immune response and a strong repression of several mitochondrial proteins. Complementing the proteome studies, the phospho-proteomic survey found an abundance of phospho-site alterations in plasma membrane and cytoskeletal proteins. Bioinformatic analysis of kinase activity provided substantial evidence for the activation of NDRG2 and JNK/p38 kinases during Chagas disease. A significant activation of DYRK2 and AMPKA2 and the inhibition of casein family kinases were also predicted. We concluded our analyses by linking the diseased heart proteome profile to known therapeutic interventions, uncovering a potential to target mitochondrial proteins, secreted immune effectors and core kinases for the treatment of chronic Chagas disease. Together, this study provides molecular insight into host proteome and phospho-proteome responses to T. cruzi infection in the heart for the first time, highlighting pathways that can be further validated for functional contributions to disease and suitability as drug targets.

UNC5B-AS1 promoted ovarian cancer progression by regulating the H3K27me on NDRG2 via EZH2

The role of long non-coding RNAs (lncRNAs) in tumorigenesis and development of ovarian cancer (OC) has caught the attention of scientists. UNC5B antisense RNA 1 (UNC5B-AS1) is a newly identified carcinogenic lncRNA in thyroid papillary carcinoma, but its role in OC remains unclear. This study is proposed to investigate the function and mechanism of UNC5B-AS1 in OC. UNC5B-AS1 expression in OC samples was obtained from gene expression profiling interactive analysis (GEPIA) based on The Cancer Genome Atlas data. Gene expressions were detected by quantitative real-time polymerase chain reaction (RT-qPCR) and western blot. Biological functions of UNC5B-AS1 were assessed by cell counting kit-8, colony formation, and caspase-3 analysis. GEPIA revealed the UNC5B-AS1 upregulation in OC samples. RT-qPCR assay confirmed the upregulation of UNC5B-AS1 in OC cells. Functionally, depletion of UCN5B-AS1 hindered proliferation and prompted apoptosis in OC cells. Mechanistically, we found that UNC5B-AS1 interacted with zeste 2 polycomb repressive complex 2 subunit (EZH2) to trigger trimethylation of histone H3 at lysine 27 (H3K27me3) on N-myc downstream regulated gene-2 (NDRG2) promoter and epigenetically repressed NDRG2. Rescue assay indicated the participation of NDRG2 in the regulation of UNC5B-AS1 on OC progression. Together, we first illustrated that UNC5B-AS1 promoted OC progression by regulating the H3K27me on NDRG2 via EZH2, indicating UNC5B-AS1 as a potential molecular target for OC treatment.

N-myc downstream-regulated gene 2 deficiency aggravates memory impairment in Alzheimer's disease

Alzheimer's disease (AD) is a chronic degenerative disease of the central nervous system and the most common dementia type in elderly people. N-myc downstream-regulated gene 2 (NDRG2), a cell stress response gene, is primarily expressed in astrocytes in mammalian brains. The hippocampal protein levels of NDRG2 in AD patients were significantly higher than those in healthy peers. However, whether the increase in NDRG2 is involved in the development of AD or is an endogenous protective response initiated by stress remains unknown. Here, we investigated the roles of NDRG2 in the development of memory impairment in AD using mouse models established by amyloid β injection or crossing of APP/PS1 mice. We found that NDRG2 deficiency worsened the memory impairment in AD mice. In addition, NDRG2 deletion induced downregulation of the proteasome functional subunit PSMB6 in AD mice. These findings suggest that NDRG2 is an endogenous neuroprotectant that participates in the pathological course of waste-clearing impairment and memory damage in AD. NDRG2 may be a therapeutic target for the intervention of AD memory degradation.

NELFE promoted pancreatic cancer metastasis and the epithelial‑to‑mesenchymal transition by decreasing the stabilization of NDRG2 mRNA

Negative elongation factor E (NELFE) has been demonstrated to promote cancer progression as an RNA‑binding protein (RBP). However, the expression patterns, biological role and molecular mechanism of NELFE in pancreatic cancer (PC) remain largely unknown. The expression levels of NELFE in 120 pairs of PC tissues and adjacent non‑tumor clinical samples collected from patients with PC were examined via reverse transcription‑quantitative (RT‑q) PCR and immunohistochemistry. The mRNA expression levels of NELFE, N‑Myc downstream‑regulated gene 2 (NDRG2), c‑Myc, survivin and cyclin D1 were detected via RT‑qPCR. The protein expression levels of NELFE, NDRG2, total β‑catenin, nuclear β‑catenin, cytosolic β‑catenin, E‑cadherin, N‑cadherin and Vimentin were measured by western blotting. NELFE and NDRG2 were then knocked‑down by short hairpin (sh)RNA. PC cell proliferation was detected by MTT and colony formation assays. Invasion and migration were detected by transwell assays. The interaction between NELFE and NDRG2 was detected by luciferase reporter assays, mRNA decay assays and RNA immunoprecipitation. NELFE expression was increased in PC tissues compared with the paired non‑cancerous tissues. NELFE expression was upregulated in PC cells when compared with normal pancreatic cells (HPDE6‑C7). The present study revealed that knockdown of NELFE inhibited the proliferation, invasion and migration of PC cells. In addition, transfection of the sh‑NELFE vector inhibited the epithelial‑to‑mesenchymal transition in PC cells by suppressing the expression and nuclear accumulation of β‑catenin. Further mechanistic studies revealed that NELFE activates the Wnt/β‑catenin signaling pathway by decreasing the stabilization of NDRG2 mRNA in PC. To the best of our knowledge, these results revealed the promotional function of NELFE on PC tumorigenesis and metastasis for the first time, helping to provide a promising strategy for the treatment of patients with PC.

The effects and mechanisms of a biosynthetic ginsenoside 3β,12β-Di-O-Glc-PPD on non-small cell lung cancer

Background

A biosynthetic ginsenoside, 3-O-β-D-glucopyranosyl-12-O-β-D-glucopyranosyl-dammar-24-ene-3β, 12β, 20S-triol (C₃C₁₂PPD), showed antitumor activity against many tumor cells in vitro, especially had better anti-lung cancer activity than Rg3 in vitro and in vivo. However, the effects and molecular mechanisms of C₃C₁₂PPD on non-small cell lung cancer (NSCLC) remain unclear. According to previous studies, we hypothesized ginsenoside C₃C₁₂PPD could inhibit the tumor growth of NSCLC by targeting proliferation, migration and angiogenesis.

Methods

A thiazolyl blue tetrazolium bromide assay (MTT) was performed to evaluate cell viability. Additionally, Transwell and tube formation assays were conducted to analyze cell migration and angiogenesis. The Lewis and A549 tumor xenograft experiments were also performed to investigate the effects of C₃C₁₂PPD on tumor growth in vivo, Western blotting and IHC assay were performed to analyze protein expression.

Results

C₃C₁₂PPD could effectively inhibit the proliferation and migration of lung cancer cells, and tube formation of EA.hy926 cell. Ginsenoside C₃C₁₂PPD suppressed Lewis and A549 tumor growth in vivo without obvious side effects on body weight and the hematology index. In addition, the Western blot analysis revealed that the effects of C₃C₁₂PPD on lung cancer were mediated by inhibiting Raf/MEK/ERK, AKT/mTOR and AKT/GSK-3β/β-Catenin signaling pathways. Finally, C₃C₁₂PPD could significantly inhibit the proliferation index and vessel number in Lewis xenograft tumors analyzed by IHC.

Conclusion

The results of the present study suggest that ginsenoside C₃C₁₂PPD may serve as a potential therapeutic candidate compound against NSCLC.

Combined Aberrant Expression of NDRG2 and LDHA Predicts Hepatocellular Carcinoma Prognosis and Mediates the Anti-tumor Effect of Gemcitabine

The Warburg effect is one of the important hallmarks of cancer. The activation of oncogene and inactivation of tumor suppressor gene contribute to the enhancement of glycolytic enzymes and the Warburg effect. The N-myc downstream regulated gene 2 (NDRG2) is a tumor suppressor gene and is frequently lost in various types of cancer. However, little is known about glycolytic function and therapeutic value of NDRG2 in hepatocellular carcinoma (HCC). In this study, we found that NDRG2 and lactate dehydrogenase A (LDHA) were aberrantly expressed in HCC and were closely related to the Warburg effect. The correlation between NDRG2 and LDHA expression predicted HCC prognosis and the clinical response to chemotherapy. NDRG2 expression was significantly decreased while LDHA expression was increased in HCC specimens. NDRG2 and LDHA expression was significantly correlated with differentiation status, vascular invasion, and TNM stage of HCC. NDRG2 inhibited LDHA expression, the Warburg effect and the growth of HCC cells. Furthermore, NDRG2 mediated gemcitabine-induced inhibition of LDHA expression and the Warburg effect in HCC cells. Taken together, our data suggest that NDRG2 plays an important role in inhibiting the Warburg effect and the malignant growth of HCC via LDHA. NDRG2 combined with LDHA might be powerful prognostic biomarkers and targets for chemotherapy treatment of HCC.

Expression of NDRG2 in Human Colorectal Cancer and its Association with Prognosis

Objective: As a member of the N-myc downregulated gene family, N-Myc downstream-regulated gene 2 (NDRG2) contributes to tumorigenesis of various types of cancer. The expression status of NDRG2 in colorectal cancer (CRC) and its prognostic value remain to be elucidated. The goal of this study was to determine the expression pattern of NDRG2 in human CRC and its association of NDRG2 expression with prognosis.

Methods: Immunohistochemistry was used to determine the level of NDRG2 expressions in 316 CRC tissues. The medical records of consecutive CRC patients undergoing primary tumor resection from September 2000 to February 2015 were retrospectively selected. Then, we compared to specific clinicopathological features in patients with different level of NDRG2 expressions. The correlation of NDRG2 expression with 3-year survival rate was assessed by Kaplan-Meier method and Cox regression modeling.

Results: NDRG2 was expressed in 94.6% (299/316) of CRC tissues. The median IHC score of NDRG2 expression was significantly lower in tumor tissues compared with that of tumor-adjacent normal tissues [4.50(range 0.00-12.00) vs. 10.00 (range 0.00-12.00), P < 0.001].Survival analysis indicated that patients with low NDRG2 expression had poorer 3-year OS than those with high NDRG2 expression (59.9% vs. 76.6%, P = 0.017). Low NDRG2 expression also presented a significantly poorer 3-year OS rate in patient with stage IV disease (29.4% vs. 56.5%, P = 0.002), liver metastasis(32.2% vs. 54.7%, P = 0.005) and those receiving liver resection(56.5% vs. 71.9% , P = 0.012). Multivariate analysis indicated that high NDRG2 expression was independently associated with poor OS (hazard ratio [HR]: 1.499; 95% confidence interval [CI]: 1.037-2.165; P = 0.031).

Conclusions: Low expression of NDRG2 was associated with unfavorable prognosis in CRC patients with primary tumor resection. Detection of NDRG2 expression might be useful for providing valuable information of individualized therapy for CRC patients.

Clinical and Molecular Comparative Study of Colorectal Cancer Based on Age-of-onset and Tumor Location: Two Main Criteria for Subclassifying Colorectal Cancer

Our aim was to characterize and validate that the location and age of onset of the tumor are both important criteria to classify colorectal cancer (CRC). We analyzed clinical and molecular characteristics of early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and we compared each tumor location between both ages-of-onset. In right-sided colon tumors, early-onset cases showed extensive Lynch syndrome (LS) features, with a relatively low frequency of chromosomal instability (CIN), but a high CpG island methylation phenotype. Nevertheless, late-onset cases showed predominantly sporadic features and microsatellite instability cases due to BRAF mutations. In left colon cancers, the most reliable clinical features were the tendency to develop polyps as well as multiple primary CRC associated with the late-onset subset. Apart from the higher degree of CIN in left-sided early-onset cancers, differential copy number alterations were also observed. Differences among rectal cancers showed that early-onset rectal cancers were diagnosed at later stages, had less association with polyps, and more than half of them were associated with a familial LS component. Stratifying CRC according to both location and age-of-onset criteria is meaningful, not only because it correlates the resulting categories with certain molecular bases, but with the confirmation across larger studies, new therapeutical algorithms could be defined according to this subclassification.

Emerging roles of long non-coding RNAs in tumor metabolism

Compared with normal cells, tumor cells display distinct metabolic characteristics. Long non-coding RNAs (lncRNAs), a large class of regulatory RNA molecules with limited or no protein-coding capacity, play key roles in tumorigenesis and progression. Recent advances have revealed that lncRNAs play a vital role in cell metabolism by regulating the reprogramming of the metabolic pathways in cancer cells. LncRNAs could regulate various metabolic enzymes that integrate cell malignant transformation and metabolic reprogramming. In addition to the known functions of lncRNAs in regulating glycolysis and glucose homeostasis, recent studies also implicate lncRNAs in amino acid and lipid metabolism. These observations reveal the high complexity of the malignant metabolism. Elucidating the metabolic-related functions of lncRNAs will provide a better understanding of the regulatory mechanisms of metabolism and thus may provide insights for the clinical development of cancer diagnostics, prognostics and therapeutics.

Activation of p53 by costunolide blocks glutaminolysis and inhibits proliferation in human colorectal cancer cells

Colorectal cancer is a leading cause of cancer-related death. Glutaminolysis has been suggested as a therapeutic target for cancer. Costunolide is a natural sesquiterpene lactone showing potent antitumor activity. Our studies were aimed at evaluating how costunolide affected glutaminolysis leading to proliferation inhibition in human colorectal cancer cells. Costunolide suppressed viability and proliferation of HCT116 cells concentration-dependently, but did not apparently affect human intestinal epithelial cells. Costunolide at 20 μM reduced viability and proliferation of HCT116 cells time-dependently. Costunolide also repressed phosphorylation of mTOR and its downstream kinases p70S6K and 4E-BP1. Examinations of glutaminolysis metabolites showed that costunolide increased intracellular glutamine levels, but decreased intracellular levels of glutamate, α-ketoglutarate (α-KG), and ATP in HCT116 cells, suggesting costunolide blockade of glutaminolysis. Furthermore, costunolide inhibited promoter activity of glutaminase 1 (GLS1), the first rate-limiting enzyme in glutaminolysis, and reduced mRNA and protein expression of GLS1 in HCT116 cells, The GLS1 inhibitor BPTES, similar to costunolide, significantly reduced intracellular levels of α-KG and ATP and inhibited proliferation in HCT116 cells. Finally, costunolide increased phosphorylation and nuclear translocation of p53 in HCT116 cells. Both p53 inhibitor pifithrin-α and p53 siRNA significantly rescued costunolide suppression of GLS1 promoter activity and expression in HCT116 cells. These data in aggregate suggested that activation of p53 was required for costunolide inhibition of GLS1 resulting in blockade of glutaminolysis and inhibition of proliferation in colorectal cancer cells, which was a novel mechanism underlying the antitumor activity of costunolide against colorectal cancer.

NDRG2 promotes adriamycin sensitivity through a Bad/p53 complex at the mitochondria in breast cancer

Chemo-resistance presents a difficult challenge for the treatment of breast cancer. Our previous study showed that N-Myc downstream-regulated gene 2 (NDRG2) is involved in p53-mediated apoptosis induced by chemotherapy, through a mechanism that has so far remained obscure. Here, we explored the role of NDRG2 in chemo-resistance with a focus on Adriamycin (ADR) and found that NDRG2 expression decreased in ADR resistance breast cancer cells. Interestingly, NDRG2 can promote ADR sensitivity by inhibiting proliferation, enhancing cellular damage responses, and promoting apoptosis in a p53-dependent manner. We also found that NDRG2 could upregulate Bad expression by increasing its half-life, which is associated with p53 to mitochondria. Hence, our collective data provided the first evidence that NDRG2 promoting sensitivity of breast cancer is dependent on p53 by preventing p53 from entering the nucleus rather than changing its expression.

Potential role of the N-MYC downstream-regulated gene family in reprogramming cancer metabolism under hypoxia

Metabolic reprogramming toward aerobic glycolysis and lactate fermentation supplies cancer cells with intermediate metabolites, which are used as macromolecule precursors. The oncogene MYC contributes to such aerobic metabolism by activating the expression of numerous genes essential for glycolysis and mitochondrial biogenesis. However, to survive and evolve in a hypoxic tumor milieu, cancer cells must revise MYC-driven metabolism because the mitochondrial respiratory chain provides free electrons to generate oxygen free radicals with inefficient production of ATP due to oxygen depletion. Instead, hypoxia-inducible transcription factor hypoxia-inducible factor 1 (HIF-1) takes over the role of MYC in glycolysis, but suppresses mitochondrial biogenesis and activity to protect cells from such threats. Recently, the N-MYC downstream-regulated gene (NDRG) family has received attention as potential biomarkers of cancer prognosis. NDRGs are repressed MYC-dependently in various cancers, but induced under hypoxia because HIF-1 directly activates their promoters and indirectly de-represses them by antagonizing MYC. In this review, we summarize the current understanding of the reprogramming of cancer metabolism via the counterbalance between MYC and HIF-1, and discuss the proven and putative roles of the NDRG family in adjusting cancer metabolism according to the ambient oxygen level.

FoxO3a confers cetuximab resistance in RAS wild-type metastatic colorectal cancer through c-Myc

Resistance to epidermal growth factor receptor (EGFR) targeted monoclonal antibody therapy represents a clinical challenge in patients suffered from RAS wild-type (WT) metastatic colorectal cancer (mCRC). However, the molecular mechanisms and key factors conferring this resistance are largely unknown. Forkhead transcription factors of the O class 3a (FoxO3a), an important regulator of cell survival, has been reported with dual functions in tumor recently. In this study, we found that FoxO3a was highly expressed in cetuximab resistant CRC tissues compared with cetuximab sensitive tissues. We therefore further analyzed its function in induced cetuximab resistant RAS-WT CRC cells (Caco2-CR) and intrinsic resistant cells with BRAF mutation (HT29). We found that FoxO3a was significantly up-regulated in Caco2-CR as well as in cetuximab treated HT29 cells. Knockdown of FoxO3a could sensitize these cells to cetuximab treatment with reduced cell proliferation and migration ability. Further, biochemical experiments demonstrated that FoxO3a directly bind to c-Myc promoter and activated the transcription of the c-Myc gene, thus participated in regulating of c-Myc downstream genes, including ACO2, LARS2, MRPL12 and PKM2 in these resistant cells. Moreover, knockdown of c-Myc elevated cell apoptosis to cetuximab treatment and suppressed cell proliferation and migration ability consistently. Altogether, our study indicates that FoxO3a might be a key regulator in cetuximab resistance through up-regulating c-Myc in colorectal cancer targeted therapy.