Downregulation of FBP1 Promotes Tumor Metastasis and Indicates Poor Prognosis in Gastric Cancer via Regulating Epithelial-Mesenchymal Transition

Identification of key hub genes associated with anti-gastric cancer effects of lotus plumule based on machine learning algorithms

BACKGROUND

Lotus plumule and its active components have demonstrated inhibitory effects on gastric cancer (GC). However, the molecular mechanism of lotus plumule against GC remains unclear and requires further investigation.

AIM

To identify the key hub genes associated with the anti-GC effects of lotus plumule.

METHODS

This study investigated the potential targets of traditional Chinese medicine for inhibiting GC using weighted gene co-expression network analysis and bioinformatics. Initially, the active components and targets of the lotus plumule and the differentially expressed genes associated with GC were identified. Subsequently, a protein-protein interaction network was constructed to elucidate the interactions between drug targets and disease-related genes, facilitating the identification of hub genes within the network. The clinical significance of these hub genes was evaluated, and their upstream transcription factors and downstream targets were identified. The binding ability of a hub gene with its downstream targets was verified using molecular docking technology. Finally, molecular docking was performed to evaluate the binding affinity between the active ingredients of lotus plumule and the hub gene.

RESULTS

This study identified 26 genes closely associated with GC. Machine learning analysis and external validation narrowed the list to four genes: Aldo-keto reductase family 1 member B10, fructose-bisphosphatase 1, protein arginine methyltransferase 1, and carbonic anhydrase 9. These genes indicated a strong correlation with anti-GC activity.

CONCLUSION

Lotus plumule exhibits anti-GC effects. This study identified four hub genes with potential as novel targets for diagnosing and treating GC, providing innovative perspectives for its clinical management.

The role of fructose-1,6-bisphosphatase 1 on regulating the cancer progression and drug resistance

Fructose-1,6-bisphosphatase 1 (FBP1) is the enzyme that limits the process of gluconeogenesis as it facilitates the hydrolysis of fructose-1,6-bisphosphate(F-1,6-BP) to produce fructose-6-phosphate(F6P) and inorganic phosphate. Gluconeogenesis is the production of glucose from small carbohydrate substrates. The gluconeogenic process is typically suppressed in cancer because it inhibits glycolysis. Apart from its involvement in cellular glucose metabolism, FBP1 also plays a role in gene transcription, mRNA translation and stability regulation, and the immune microenvironment of tumors. Because of its multifaceted functions, the mechanisms by which FBP1 is involved in tumor development are complex. Moreover, FBP1 deficiency is associated with radiation and chemotherapy resistance and poor prognosis in cancer patients. Restoration of FBP1 expression in cancer cells is expected to hold promise for cancer therapy. However, up to now few reviews have systematically summarized the important functional mechanisms of FBP1 in tumorigenesis and the small molecule compounds that restore FBP1 expression. Therefore, this article addresses the question "How does FBP1 contribute to cancer progression, and can targeting FBP1 be a potential therapeutic approach?" by summarizing the effects of FBP1 on cancer development and progression as well as its mediated drug resistance and the future clinical applications of potential small molecule modulators targeting FBP1.

Fructose-1,6-bisphosphatase 1 in cancer: Dual roles, mechanistic insights, and therapeutic potential - A comprehensive review

Fructose-1,6-bisphosphatase 1 (FBP1) is a key gluconeogenic enzyme that plays complex and context-dependent roles in cancer biology. This review comprehensively examines FBP1's dual functions as both a tumor suppressor and an oncogene across various cancer types. In many cancers, such as hepatocellular carcinoma, clear cell renal cell carcinoma, and lung cancer, downregulation of FBP1 contributes to tumor progression through metabolic reprogramming, promoting glycolysis, and altering the tumor microenvironment. Conversely, in certain contexts like breast and prostate cancers, FBP1 overexpression is associated with tumor promotion, indicating its oncogenic potential. The review explores FBP1's interactions with immune cells within the tumor microenvironment, influencing immune surveillance and tumor immune escape mechanisms. Additionally, FBP1 emerges as a promising diagnostic and prognostic biomarker, with expression levels correlating with patient outcomes in multiple cancers. Future therapeutic strategies targeting FBP1 are discussed, including inhibitors, activators, epigenetic modulation, and combination therapies, while addressing the challenges posed by its dual nature. Understanding the multifaceted roles of FBP1 offers valuable insights into cancer metabolism and opens avenues for personalized therapeutic interventions.

Integrated analysis of single-cell and bulk-RNA sequencing for the cellular senescence in prognosis of lung adenocarcinoma

Non-small cell lung cancer (NSCLC), half of which are lung adenocarcinoma (LUAD), is one of the most widely spread cancers in the world. Telomerase, which maintains telomere length and chromosomal integrity, enables cancer cells to avoid replicative senescence. When telomerase is inhibited, cancer cells' senescence began, preventing them from growing indefinitely. Cellular senescence and telomeres are intrinsically linked. As of yet, still laking a systematic study of the involvement of telomere-senescence related genes in lung adenocarcinoma development. In this study, myeloid cells were identified as the cell type which are most correlated with cellular senescence based on its highest telomere-related gene activity. GO, KEGG, GSEA and GSVA analyses were used to explore the biological function of telomere-senescence related genes in LUAD. The combined analysis of single-cell RNA-sequencing and bulk-RNA sequencing identified a gene signature composed of 14 genes which can accurately predict the prognosis of patients with LUAD. In one training and four validation sets, patients with higher Telomere Related Gene Signature (TRGS) had a worse prognosis than those with lower TRGS. Different TRGS patient groups showed varying degrees of immune cell infiltration, frequency of gene missense mutation, sensitivity to different drugs, and tumor mutation burden (TMB). Collectively, we developed a brand new signature composed of telomere-senescence related genes that can accurately predicts patients' prognosis in LUAD, which provides new insights for future research into the role of cellular senescence in LUAD.

Exploring the Functions of Mutant p53 through TP53 Knockout in HaCaT Keratinocytes

Approximately 50% of tumors carry mutations in TP53; thus, evaluation of the features of mutant p53 is crucial to understanding the mechanisms underlying cell transformation and tumor progression. HaCaT keratinocytes represent a valuable model for research in this area since they are considered normal, although they bear two gain-of-function mutations in TP53. In the present study, transcriptomic and proteomic profiling were employed to examine the functions of mutant p53 and to investigate the impact of its complete abolishment. Our findings indicate that CRISPR-mediated TP53 knockout results in significant changes at the transcriptomic and proteomic levels. The knockout of TP53 significantly increased the migration rate and altered the expression of genes associated with invasion, migration, and EMT but suppressed the epidermal differentiation program. These outcomes suggest that, despite being dysfunctional, p53 may still possess oncosuppressive functions. However, despite being considered normal keratinocytes, HaCaT cells exhibit oncogenic properties.

FOXP2 suppresses the proliferation, invasion, and aerobic glycolysis of hepatocellular carcinoma cells by regulating the KDM5A/FBP1 axis

The Warburg effect is the preference of cancer cells to use glycolysis rather than oxidative phosphorylation to generate energy. Accumulating evidence suggests that aerobic glycolysis is widespread in hepatocellular carcinoma (HCC) and closely related to tumorigenesis. The purpose of this study was to investigate the role and mechanism of forkhead box P2 (FOXP2) in aerobic glycolysis and tumorigenesis in HCC. Here, we found that FOXP2 was lower expressed in HCC tissues and cells than in nontumor tissues and normal hepatocytes. Overexpression of FOXP2 suppressed cell proliferation and invasion of HCC cells and promoted cell apoptosis in vitro, and hindered the growth of mouse xenograft tumors in vivo. Further researches showed that FOXP2 inhibited the Warburg effect in HCC cells. Moreover, we demonstrated that FOXP2 up-regulated the expression of fructose-1, 6-diphosphatase (FBP1), and the inhibitory effect of FOXP2 on glycolysis was dependent on FBP1. Mechanistically, as a transcription factor, FOXP2 negatively regulated the transcription of lysine-specific demethylase 5A (KDM5A), and then blocked KDM5A-induced H3K4me3 demethylation in FBP1 promoter region, thereby promoting the expression of FBP1. Consistently, overexpressing KDM5A or silencing FBP1 effectively reversed the inhibitory effect of FOXP2 on HCC progression. Together, our findings revealed the mechanistic role of the FOXP2/KDM5A/FBP1 axis in glycolysis and malignant progression of HCC cells, providing a potential molecular target for the therapy of HCC.

Down-regulation of FBP1 in lung adenocarcinoma cells promotes proliferation and invasion through SLUG mediated epithelial mesenchymal transformation

Background

Metabolic reprogramming and epithelial-mesenchymal transformation (EMT) play an important role in lung cancer. In recent studies, metabolic enzymes such as Fructose-1,6-bisphosphatase 1 (FBP1) have shown potential functions beyond regulating metabolism.

Methods

Western blot assay was performed to detect glycolysis-related and EMT-related protein expression levels. The glucose uptake kit and adenosine triphosphate (ATP) detection kit were used to detect glucose uptake rate and ATP content. Transwell assay was used to determine the invasiveness of lung adenocarcinoma cells. Wound healing assay was used to determine the metastatic ability of lung adenocarcinoma cells. Methyl thiazolyl tetrazolium (MTT) assay and EdU staining were performed to investigate the effect of FBP1 overexpression on lung adenocarcinoma proliferation.

Results

Overexpression of FBP1 down-regulated glycolysis-related protein levels and inhibited glucose uptake and ATP production, while knockdown of FBP1 had the opposite effect. Overexpression of FBP1 reversed EMT and inhibited Slug expression. Meanwhile, overexpression of FBP1 impaired the invasion, metastasis and proliferation ability of lung adenocarcinoma cells. In contrast, FBP1 knockdown promoted the EMT process, up-regulated Slug expression and enhanced the invasion, metastasis and proliferation of lung adenocarcinoma cells.

Conclusions

Therefore, FBP1 can be used as one of the potential clinical targets through inhibiting glycolysis, cell invasion and proliferation by inhibiting Slug mediated EMT processes.

Revisited Metabolic Control and Reprogramming Cancers by Means of the Warburg Effect in Tumor Cells

Aerobic glycolysis is an emerging hallmark of many human cancers, as cancer cells are defined as a "metabolically abnormal system". Carbohydrates are metabolically reprogrammed by its metabolizing and catabolizing enzymes in such abnormal cancer cells. Normal cells acquire their energy from oxidative phosphorylation, while cancer cells acquire their energy from oxidative glycolysis, known as the "Warburg effect". Energy-metabolic differences are easily found in the growth, invasion, immune escape and anti-tumor drug resistance of cancer cells. The glycolysis pathway is carried out in multiple enzymatic steps and yields two pyruvate molecules from one glucose (Glc) molecule by orchestral reaction of enzymes. Uncontrolled glycolysis or abnormally activated glycolysis is easily observed in the metabolism of cancer cells with enhanced levels of glycolytic proteins and enzymatic activities. In the "Warburg effect", tumor cells utilize energy supplied from lactic acid-based fermentative glycolysis operated by glycolysis-specific enzymes of hexokinase (HK), keto-HK-A, Glc-6-phosphate isomerase, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase, phosphofructokinase (PFK), phosphor-Glc isomerase (PGI), fructose-bisphosphate aldolase, phosphoglycerate (PG) kinase (PGK)1, triose phosphate isomerase, PG mutase (PGAM), glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase isozyme type M2 (PKM2), pyruvate dehydrogenase (PDH), PDH kinase and lactate dehydrogenase. They are related to glycolytic flux. The key enzymes involved in glycolysis are directly linked to oncogenesis and drug resistance. Among the metabolic enzymes, PKM2, PGK1, HK, keto-HK-A and nucleoside diphosphate kinase also have protein kinase activities. Because glycolysis-generated energy is not enough, the cancer cell-favored glycolysis to produce low ATP level seems to be non-efficient for cancer growth and self-protection. Thus, the Warburg effect is still an attractive phenomenon to understand the metabolic glycolysis favored in cancer. If the basic properties of the Warburg effect, including genetic mutations and signaling shifts are considered, anti-cancer therapeutic targets can be raised. Specific therapeutics targeting metabolic enzymes in aerobic glycolysis and hypoxic microenvironments have been developed to kill tumor cells. The present review deals with the tumor-specific Warburg effect with the revisited viewpoint of recent progress.

Essential role of aerobic glycolysis in epithelial-to-mesenchymal transition during carcinogenesis

Epithelial-to-mesenchymal transition (EMT) confers the most lethal characteristics to cancer cells i.e., metastasis and resistance to chemo-and-radio-therapy, and therefore exhibit an appealing target in the field of oncology. Research in the past decade has demonstrated the crucial role of aerobic glycolysis in EMT, which is generally credited as the glucose metabolism for the creation of biomass such as fatty acids, amino acids, and nucleotides thereby providing building blocks for limitless proliferation. In the present review, apart from discussing EMT's evident role in the metastatic process and cancer stemness, we also talked about the vital role of glycolytic enzymes viz. GLUTs, HKs, PGI, PFK-1, aldolase, enolase, PK, LDHA, etc. in the induction of the EMT process in cancerous cells.

Fructose-1,6-bisphosphatase 1 (FBP1) is an independent biomarker associated with a favorable prognosis in esophageal adenocarcinoma

Introduction

Despite modern multimodal therapeutic regimens, the prognosis of esophageal adenocarcinoma (EAC) is still poor and there is a lack of biological markers estimating the patients’ prognosis. Fructose-1,6-biphosphatase (FBP1) is a key enzyme in gluconeogenesis and is associated with tumor initiation in several cancers. Therefore, this study aims to characterize its implication for EAC patients.

Methods and materials

A total of 571 EAC patients who underwent multimodal treatment between 1999 and 2017 were analyzed for FBP1 expression using immunohistochemistry.

Results

82.5% of the EACs show FBP1 expression in the tumor albeit with different intensities categorizing specimens accordingly into score 0 (no expression), score 1 (weak expression), score 2 (moderate expression) and score 3 (strong expression) (score 1 = 25.0%, score 2 = 35.9%, score 3 = 21.5%). Intratumoral FBP1 expression was significantly associated with a better prognosis (p = 0.024). This observation was particularly relevant among patients who received primary surgery without neoadjuvant treatment (p = 0.004). In multivariate analysis, elevated FBP1 expression was an independent biomarker associated with a favorable prognosis.

Discussion

Despite being associated with a favorable prognosis, the majority of patients with high FBP1 expression also require individualized therapy options to ensure long-term survival. Recently, it has been shown that the presence of the FBP1 protein increases the sensitivity of pancreatic cancer cells to the bromodomain and extraterminal domain (BET) inhibitor JQ1.

Conclusion

We described for the first time the prognostic and possibly therapeutic relevance of FBP1 in EAC. The efficiency of the BET inhibitor in EAC should be verified in clinical studies and special attention should be paid to the effects of neoadjuvant therapy on FBP1 expression.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-04025-x.

The role of fructose 1,6-bisphosphate-mediated glycolysis/gluconeogenesis genes in cancer prognosis

Metabolic reprogramming and elevated glycolysis levels are associated with tumor progression. However, despite cancer cells selectively inhibiting or expressing certain metabolic enzymes, it is unclear whether differences in gene profiles influence patient outcomes. Therefore, identifying the differences in enzyme action may facilitate discovery of gene ontology variations to characterize tumors. Fructose-1,6-bisphosphate (F-1,6-BP) is an important intermediate in glucose metabolism, particularly in cancer. Gluconeogenesis and glycolysis require fructose-1,6-bisphosphonates 1 (FBP1) and fructose-bisphosphate aldolase A (ALDOA), which participate in F-1,6-BP conversion. Increased expression of ALDOA and decreased expression of FBP1 are associated with the progression of various forms of cancer in humans. However, the exact molecular mechanism by which ALDOA and FBP1 are involved in the switching of F-1,6-BP is not yet known. As a result of their pancancer pattern, the relationship between ALDOA and FBP1 in patient prognosis is reversed, particularly in lung adenocarcinoma (LUAD) and liver hepatocellular carcinoma (LIHC). Using The Cancer Genome Atlas (TCGA), we observed that FBP1 expression was low in patients with LUAD and LIHC tumors, which was distinct from ALDOA. A similar trend was observed in the analysis of Cancer Cell Line Encyclopedia (CCLE) datasets. By dissecting downstream networks and possible upstream regulators, using ALDOA and FBP1 as the core, we identified common signatures and interaction events regulated by ALDOA and FBP1. Notably, the identified effectors dominated by ALDOA or FBP1 were distributed in opposite patterns and can be considered independent prognostic indicators for patients with LUAD and LIHC. Therefore, uncovering the effectors between ALDOA and FBP1 will lead to novel therapeutic strategies for cancer patients.

Quantifying the Patterns of Metabolic Plasticity and Heterogeneity along the Epithelial–Hybrid–Mesenchymal Spectrum in Cancer

Cancer metastasis is the leading cause of cancer-related mortality and the process of the epithelial-to-mesenchymal transition (EMT) is crucial for cancer metastasis. Both partial and complete EMT have been reported to influence the metabolic plasticity of cancer cells in terms of switching among the oxidative phosphorylation, fatty acid oxidation and glycolysis pathways. However, a comprehensive analysis of these major metabolic pathways and their associations with EMT across different cancers is lacking. Here, we analyse more than 180 cancer cell datasets and show the diverse associations of these metabolic pathways with the EMT status of cancer cells. Our bulk data analysis shows that EMT generally positively correlates with glycolysis but negatively with oxidative phosphorylation and fatty acid metabolism. These correlations are also consistent at the level of their molecular master regulators, namely AMPK and HIF1α. Yet, these associations are shown to not be universal. The analysis of single-cell data for EMT induction shows dynamic changes along the different axes of metabolic pathways, consistent with general trends seen in bulk samples. Further, assessing the association of EMT and metabolic activity with patient survival shows that a higher extent of EMT and glycolysis predicts a worse prognosis in many cancers. Together, our results reveal the underlying patterns of metabolic plasticity and heterogeneity as cancer cells traverse through the epithelial–hybrid–mesenchymal spectrum of states.

Glucagon signaling via supraphysiologic GCGR can reduce cell viability without stimulating gluconeogenic gene expression in liver cancer cells

Background

Deregulated glucose metabolism is a critical component of cancer growth and survival, clinically evident via FDG-PET imaging of enhanced glucose uptake in tumor nodules. Tumor cells utilize glucose in a variety of interconnected biochemical pathways to generate energy, anabolic precursors, and other metabolites necessary for growth. Glucagon-stimulated gluconeogenesis opposes glycolysis, potentially representing a pathway-specific strategy for targeting glucose metabolism in tumor cells. Here, we test the hypothesis of whether glucagon signaling can activate gluconeogenesis to reduce tumor proliferation in models of liver cancer.

Methods

The glucagon receptor, GCGR, was overexpressed in liver cancer cell lines consisting of a range of etiologies and genetic backgrounds. Glucagon signaling transduction was measured by cAMP ELISAs, western blots of phosphorylated PKA substrates, and qPCRs of relative mRNA expression of multiple gluconeogenic enzymes. Lastly, cell proliferation and apoptosis assays were performed to quantify the biological effect of glucagon/GCGR stimulation.

Results

Signaling analyses in SNU398 GCGR cells treated with glucagon revealed an increase in cAMP abundance and phosphorylation of downstream PKA substrates, including CREB. qPCR data indicated that none of the three major gluconeogenic genes, G6PC, FBP1, or PCK1, exhibit significantly higher mRNA levels in SNU398 GCGR cells when treated with glucagon; however, this could be partially increased with epigenetic inhibitors. In glucagon-treated SNU398 GCGR cells, flow cytometry analyses of apoptotic markers and growth assays reproducibly measured statistically significant reductions in cell viability. Finally, proliferation experiments employing siCREB inhibition showed no reversal of cell death in SNU398 GCGR cells treated with glucagon, indicating the effects of glucagon in this setting are independent of CREB.

Conclusions

For the first time, we report a potential tumor suppressive role for glucagon/GCGR in liver cancer. Specifically, we identified a novel cell line-specific phenotype, whereby glucagon signaling can induce apoptosis via an undetermined mechanism. Future studies should explore the potential effects of glucagon in diabetic liver cancer patients.

High expression of FBP1 and LDHB in fibroadenomas and invasive breast cancers

BACKGROUND

The role of gluconeogenesis in cancer cells as the reverse pathway for glycolysis is not well known. Several studies of gluconeogenesis in cancer cells still show conflicting results. Expression of key enzymes such as FBP1 and LDHB in cancer tissues may explain the role of gluconeogenesis in tumor development.

OBJECTIVE

This study aimed to analyze the expression of FBP1 and LDHB in fibroadenomas and invasive cancers of the breast.

METHODS

The immunohistochemical staining technique was used to show the expression of FBP1 and LDHB in formalin-fixed, paraffin-embedded blocks of 32 fibroadenomas and 31 invasive breast cancer samples.

RESULTS

FBP1 was expressed by the majority of fibroadenoma (68.7%) and invasive breast cancer (71%) samples. LDHB expression in fibroadenomas was significantly higher than in invasive breast cancers (P = 0.029). The expression of these two enzymes was found in lobular, ductal, and NST types of invasive breast cancers, and at low, intermediate, and high grades of malignancy.

CONCLUSIONS

High expression of FBP1 and LDHB was found in fibroadenomas and invasive breast cancers. A higher level of LDHB expression was observed in fibroadenomas. These results may indicate the enzymes' role in the pathogenesis of both breast diseases.

Fructose-1,6-bisphosphatase aggravates oxidative stress-induced apoptosis in asthma by suppressing the Nrf2 pathway

Asthma is a chronic airway disease that causes excessive inflammation, oxidative stress, mucus production and bronchial epithelial cell apoptosis. Fructose‐1,6‐bisphosphatase (Fbp1) is one of the rate‐limiting enzymes in gluconeogenesis and plays a critical role in several cancers. However, its role in inflammatory diseases, such as asthma, is unclear. Here, we examined the expression, function and mechanism of action of Fbp1 in asthma. Gene Expression Omnibus (GEO) data sets revealed that Fbp1 was overexpressed in a murine model of asthma and in interleukin (IL)‐4‐ or IL‐13‐stimulated bronchial epithelial cells. We confirmed the findings in an animal model as well as Beas‐2B and 16HBE cells. In vitro investigations revealed that silencing of Fbp1 reduced apoptosis and the proportion of cells in the G2/M phase, whereas overexpression led to increases. Fbp1 knock‐down inhibited oxidative stress by activating the nuclear factor erythroid 2‐related factor 2 (Nrf2) pathway, whereas Fbp1 overexpression aggravated oxidative stress by suppressingthe Nrf2 pathway. Moreover, the Nrf2 pathway inhibitor ML385 reversed the changes caused by Fbp1 inhibition in Beas‐2B and 16HBE cells. Collectively, our data indicate that Fbp1 aggravates oxidative stress‐induced apoptosis by suppressing Nrf2 signalling, substantiating its potential as a novel therapeutic target in asthma.

A predictive model for assessing prognostic risks in gastric cancer patients using gene expression and methylation data

BACKGROUND

The role(s) of epigenetic reprogramming in gastric cancer (GC) remain obscure. This study was designed to identify methylated gene markers with prognostic potential for GC.

METHODS

Five datasets containing gene expression and methylation profiles from GC samples were collected from the GEO database, and subjected to meta-analysis. All five datasets were subjected to quality control and then differentially expressed genes (DEGs) and differentially expressed methylation genes (DEMGs) were selected using MetaDE. Correlations between gene expression and methylation status were analysed using Pearson coefficient correlation. Then, enrichment analyses were conducted to identify signature genes that were significantly different at both the gene expression and methylation levels. Cox regression analyses were performed to identify clinical factors and these were combined with the signature genes to create a prognosis-related predictive model. This model was then evaluated for predictive accuracy and then validated using a validation dataset.

RESULTS

This study identified 1565 DEGs and 3754 DEMGs in total. Of these, 369 were differentially expressed at both the gene and methylation levels. We identified 12 signature genes including VEGFC, FBP1, NR3C1, NFE2L2, and DFNA5 which were combined with the clinical data to produce a novel prognostic model for GC. This model could effectively split GC patients into two groups, high- and low-risk with these observations being confirmed in the validation dataset.

CONCLUSION

The differential methylation of the 12 signature genes, including VEGFC, FBP1, NR3C1, NFE2L2, and DFNA5, identified in this study may help to produce a functional predictive model for evaluating GC prognosis in clinical samples.

EMT Factors and Metabolic Pathways in Cancer

The epithelial-mesenchymal transition (EMT) represents a biological program during which epithelial cells lose their cell identity and acquire a mesenchymal phenotype. EMT is normally observed during organismal development, wound healing and tissue fibrosis. However, this process can be hijacked by cancer cells and is often associated with resistance to apoptosis, acquisition of tissue invasiveness, cancer stem cell characteristics, and cancer treatment resistance. It is becoming evident that EMT is a complex, multifactorial spectrum, often involving episodic, transient or partial events. Multiple factors have been causally implicated in EMT including transcription factors (e.g., SNAIL, TWIST, ZEB), epigenetic modifications, microRNAs (e.g., miR-200 family) and more recently, long non-coding RNAs. However, the relevance of metabolic pathways in EMT is only recently being recognized. Importantly, alterations in key metabolic pathways affect cancer development and progression. In this review, we report the roles of key EMT factors and describe their interactions and interconnectedness. We introduce metabolic pathways that are involved in EMT, including glycolysis, the TCA cycle, lipid and amino acid metabolism, and characterize the relationship between EMT factors and cancer metabolism. Finally, we present therapeutic opportunities involving EMT, with particular focus on cancer metabolic pathways.

OGDH promotes the progression of gastric cancer by regulating mitochondrial bioenergetics and Wnt/β-catenin signal pathway

Background/aims

2-oxoglutarate dehydrogenase (OGDH) is the first rate-limiting E1 subunit of OGDH complex (OGDHC), which plays as a regulatory point in the cross-road of TCA cycle and glutamine metabolism. Until now, the role of OGDH in carcinogenesis has been unclear.

Methods

In the present study, we determined the expression of OGDH in human gastric cancer (GC) tissues and cell lines by RT-qPCR, Western blotting and immunohistochemical staining respectively. The biological impacts of OGDH on cell growth and migration were explored through modulation OGDH expression in GC cells. Furthermore, mitochondrial functions and Wnt/β-catenin signal were analyzed to elucidate the mechanism by which OGDH was involved in GC progression.

Results

The results showed that the levels of OGDH mRNA and protein were significantly higher in GC tissues, which was positively correlated with clinicalpathological parameters of GC patients. OGDH inhibitor SP significantly suppressed GC cell viability. Modulation of OGDH had distinct effects on cell proliferation, cell cycle and cell migration in the GC cell lines AGS and BGC823. Overexpression of OGDH resulted in the downregulation of the EMT molecular markers E-cadherin and ZO-1, the upregulation of N-cadherin and claudin-1. OGDH deficiency had the opposite outcomes in GC cells. Meantime, OGDH knockdown cells showed decreased mitochondrial membrane potential, oxygen consumption rate, intracellular ATP product, and increased ROS level and NADP⁺/NADPH ratio. Consistently, overexpression of OGDH enhanced the mitochondrial function in GC cells. Furthermore, OGDH knockdown reduced the expressions of β-catenin, slug and TCF8/ZEB1, and the downstream targets cyclin D1 and MMP9 in GC cells. OGDH overexpression facilitated the activation of Wnt/β-catenin signal pathway. Additionally, overexpression of OGDH promoted tumorigenesis of GC cells in nude mice.

Conclusion

Taken together, these results indicate that OGDH serves as a positive regulator of GC progression through enhancement of mitochondrial function and activation of Wnt/β-catenin signaling.

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.

HSF2 regulates aerobic glycolysis by suppression of FBP1 in hepatocellular carcinoma

Heat shock factors (HSFs) are essential for all organisms to survive exposures to acute stress. Recent years have witnessed the progress in uncovering the importance of HSFs in cancer cell oncogenesis, progression and metastasis. However, their roles in hepatocellular carcinoma (HCC) proliferation and the underlying mechanism have seldom been discussed. The present study aims to uncover the two important HSFs members HSF1 and HSF2 in hepatocellular carcinoma (HCC). By using the Cancer Genome Atlas (TCGA) dataset analysis, we investigated the prognosis value of HSF1 and HSF2 in HCC and identified HSF2 as a prediction factor of overall survival of HCC. In vitro cell line studies demonstrated that silencing HSF2 expression could decrease the proliferation in HCC cells. In depth mechanism analysis demonstrated that HSF2 promoted cell proliferation via positive regulation of aerobic glycolysis, and HSF2 interacted with euchromatic histone lysine methyltransferase 2 (EHMT2) to epigenetically silence fructose-bisphosphatase 1 (FBP1), which is a tumor suppressor and negative regulator of aerobic glycolysis in HCC. HSF2 expression indicated unfavorable prognosis of HCC patients and it could regulate aerobic glycolysis by suppression of FBP1 to support uncontrolled proliferation of HCC cells.

Lymph-circulating tumor cells show distinct properties to blood-circulating tumor cells and are efficient metastatic precursors

The leading cause of breast cancer-associated death is metastasis. In 80% of solid tumors, metastasis via the lymphatic system precedes metastasis via the vascular system. However, the molecular properties of tumor cells as they exit the primary tumor into the afferent lymphatics en route to the sentinel lymph nodes (SLNs) are not yet known. Here, we developed an innovative technique that enables the collection of lymph and lymph-circulating tumor cells (LCTCs) en route to the SLN in an immunocompetent animal model of breast cancer metastasis. We found that the gene and protein expression profiles of LCTCs and blood-circulating tumor cells (BCTCs) as they exit the primary tumor are similar, but distinct from those of primary tumors and lymph node metastases (LNMs). LCTCs, but not BCTCs, exist in clusters, display a hybrid epithelial/mesenchymal phenotype and cancer stem cell-like properties, and are efficient metastatic precursors. These results demonstrate that tumor cells that metastasize through the lymphatic system are different from those spread by blood circulation. Understanding the relative contribution of these cells to overall peripheral blood-circulating tumor cells is important for cancer therapy. Whether these two types of cell occur in cancer patients remains to be determined.

Gluconeogenesis in cancer cells - Repurposing of a starvation-induced metabolic pathway?

Cancer cells constantly face a fluctuating nutrient supply and interference with adaptive responses might be an effective therapeutic approach. It has been discovered that in the absence of glucose, cancer cells can synthesize crucial metabolites by expressing phosphoenolpyruvate carboxykinase (PEPCK, PCK1 or PCK2) using abbreviated forms of gluconeogenesis. Gluconeogenesis, which in essence is the reverse pathway of glycolysis, uses lactate or amino acids to feed biosynthetic pathways branching from glycolysis. PCK1 and PCK2 have been shown to be critical for the growth of certain cancers. In contrast, fructose-1,6-bisphosphatase 1 (FBP1), a downstream gluconeogenesis enzyme, inhibits glycolysis and tumor growth, partly by non-enzymatic mechanisms. This review sheds light on the current knowledge of cancer cell gluconeogenesis and its role in metabolic reprogramming, cancer cell plasticity, and tumor growth.

Metabolic Regulation of Epithelial to Mesenchymal Transition: Implications for Endocrine Cancer

The last few decades have witnessed an outstanding advancement in our understanding of the hallmarks of endocrine cancers. This includes the epithelial to mesenchymal transition (EMT), a process that alters the morphology and functional characteristics of carcinoma cells. The mesenchymal stem cell like phenotype produced by EMT allows the dislocation of cancer cells from the primary tumor site with inheritance of motility, metastatic and invasive properties. A fundamental driver thought to initiate and propagate EMT is metabolic reprogramming that occur during these transitions. Though there remains a paucity of data regarding the alterations that occur during EMT in endocrine cancers, the contribution of deregulated metabolism is a prominent feature. This mini review focuses on metabolic reprogramming events that occur in cancer cells and in particular those of endocrine origin. It highlights the main metabolic reprogramming outcomes of EMT, encompassing glycolysis, mitochondria oxidative phosphorylation and function, glutamine and lipid metabolism. Comprehending the metabolic changes that occur during EMT will help formulate potential bioenergetic targets as therapies for endocrine cancer metastasis.

FBP1 loss contributes to BET inhibitors resistance by undermining c-Myc expression in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal tumor types worldwide. BET inhibitors display anti-tumor activity in pancreatic cancer, however the cells often develop resistance after a long-term treatment and the underlying molecular basis is not fully understood.

Methods

Drug screening assay in Fructose-1, 6-biphosphatase (FBP1) knockdown or overexpressing pancreatic cancer cells was performed. Tumor cell motility, FBP1 protein and mRNA changes were investigated after BET inhibitors treatment. The interaction between TRIM28 and FBP1 after BET inhibitors treatment was examined by Co-immunoprecipitation (IP) and GST pull-down. The relationship between FBP1 and c-Myc was examined by western blot, RT-qPCR and immunohistochemistry (IHC).

Results

The expression of FBP1 protein increased the sensitivity of pancreatic cancer cells to JQ1. Furthermore, we showed that JQ1 stabilized FBP1 protein level by disrupting the interaction between FBP1 and TRIM28 in pancreatic cancer cells. Moreover, we demonstrated that FBP1 promoted c-Myc degradation through disrupting the ERK-c-Myc axis.

Conclusions

FBP1 modulates the sensitivity of pancreatic cancer cells to BET inhibitors by decreasing the expression of c-Myc. These findings highlight FBP1 could be used as a therapeutic niche for patient-tailored therapies.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0888-y) contains supplementary material, which is available to authorized users.

Transcriptome Signatures of Canine Mammary Gland Tumors and Its Comparison to Human Breast Cancers

Breast cancer (BC)/mammary gland carcinoma (MGC) is the most frequently diagnosed and leading cause of cancer-related mortality in both women and canines. To better understand both canine MGC and human BC-specific genes, we sequenced RNAs obtained from eight pairs of carcinomas and adjacent normal tissues in dogs. By comprehensive transcriptome analysis, 351 differentially expressed genes (DEGs) were identified in overall canine MGCs. Based on the DEGs, comparative analysis revealed correlation existing among the three histological subtypes of canine MGC (ductal, simple, and complex) and four molecular subtypes of human BC (HER2+, ER+, ER&HER2+, and TNBC). Eight DEGs shared by all three subtypes of canine MGCs had been previously reported as cancer-associated genes in human studies. Gene ontology and pathway analyses using the identified DEGs revealed that the biological processes of cell proliferation, adhesion, and inflammatory responses are enriched in up-regulated MGC DEGs. In contrast, fatty acid homeostasis and transcription regulation involved in cell fate commitment were down-regulated in MGC DEGs. Moreover, correlations are demonstrated between upstream promoter transcripts and DEGs. Canine MGC- and subtype-enriched gene expression allows us to better understand both human BC and canine MGC, yielding new insight into the development of biomarkers and targets for both diseases.

Forced overexpression of FBP1 inhibits proliferation and metastasis in cholangiocarcinoma cells via Wnt/β-catenin pathway

AIM

To investigate the effect of fructose-1,6-bisphosphatase 1 (FBP1) on the malignant phenotypes of cholangiocarcinoma (CCA) cells, and to explore the underlying mechanism.

MAIN METHODS

The expression of FBP1 in clinical CCA tissues was detected by real-time PCR, Western blot and immunohistochemistry staining. FBP1 was overexpressed by transfection of a forced expression plasmid. MTT, plate colony formation assay, Hoechst staining, flow cytometry, Western blot, wound healing, transwell assays and xenograft were performed to detect the growth, proliferation, cell cycle, apoptosis, migration, invasion and tumorigenesis in RBE and HCCC-9801 cells. In addition, the Wnt/β-catenin signaling was detected.

KEY FINDINGS

FBP1 was downregulated in clinical CCA specimens and cell lines, compared to paired para-carcinoma tissues or normal cholangetic epithelial cells. Gain-of-function experiments demonstrated that the forced expression of FBP1 inhibited the proliferation, colony formation, and blocked cell cycle of RBE and HCCC-9801 cells. Apoptosis of CCA cells was significantly enhanced by FBP1 overexpression, evidenced by upregulation of cleaved caspase-3, cleaved PARP and Bax levels, while downregulation of Bcl-2 level. Moreover, overexpression of FBP1 decreased the migratory and invasive ability in RBE and HCCC-9801 cells. However, FBP1-induced phenotypic changes were eliminated by overexpression of β-catenin. Finally, the forced overexpression of FBP1 inhibited tumorigenesis in vivo.

SIGNIFICANCE

Our findings demonstrate that FBP1 is downregulated in CCA tissues and cell lines, and the overexpression of FBP1 inhibits the proliferation, migration, invasion and tumorigenesis of CCA cells partly via inactivation of Wnt/β-catenin pathway. FBP1 may be a novel early diagnosis marker and therapeutic target for CCA.

Aldolase A as a prognostic factor and mediator of progression via inducing epithelial-mesenchymal transition in gastric cancer

Glycolysis is regarded as the hallmark of cancer development and progression, which involves a multistep enzymatic reaction. This study aimed to explore the clinicopathological significance and potential role of glycolytic enzyme aldolase A (ALDOA) in the carcinogenesis and progression of gastric cancer (GC). ALDOA was screened from three paired liver metastasis tissues and primary GC tissues and further explored with clinical samples and in vitro studies. The ALDOA protein level significantly correlated with a larger tumor diameter (P = .004), advanced T stage (P < .001), N stage (P < .001) and lymphovascular invasion (P = .001). Moreover, the expression of ALDOA was an independent prognostic factor for the 5‐year overall survival and disease‐free survival of patients with GC in both univariate and multivariate survival analyses (P < .05). Silencing the expression of ALDOA in GC cell lines significantly impaired cell growth, proliferation and invasion ability (P < .05). Knockdown of the expression of ALDOA reversed the epithelial–mesenchymal transition process. Mechanically, ALDOA could affect the hypoxia‐inducible factor (HIF)‐1α activity as demonstrated by the HIF‐1α response element–luciferase activity in GC cells. Collectively, this study revealed that ALDOA was a potential biomarker of GC prognosis and was important in the carcinogenesis and progression of human GC.

Significance of Methylation of FBP1 Gene in Non-Small Cell Lung Cancer

Because NSCLC has poor overall prognosis and is frequently diagnosed at later stage, we aimed to seek novel diagnosis biomarkers or therapy target of the disease in this study. Fructose-1,6-bisphosphatase 1 (FBP1) is a rate-limiting enzyme in gluconeogenesis, which was usually lost in NSCLC due to abnormal methylation in promoter DNA sequence. The clinical data indicated that the methylation rate in FBP1 gene promoter was negatively related to the overall survival of the NSCLC patients. DNA methylation transferase inhibitor 5-aza treatment could significantly increase both expression levels of mRNA and protein in A549 cell line. On the other hand, silence of FBP1 in H460 cell line by using specific siRNA against FBP1 dramatically improved the cell proliferation and cell migration according to the date of FACS and transwell assays. All these findings implied the important roles of FBP1 expression in lung cancer development and progression and the potential use of the methylation status detected in FBP1 promoter region as a novel predictor for prognosis and therapeutic target for NSCLC patients.

CBX3 promotes proliferation and regulates glycolysis via suppressing FBP1 in pancreatic cancer

More and more evidence has demonstrated that Chromobox protein homolog 3(CBX3) has an important role in carcinogenesis by regulating several mechanisms, such as heterochromatin formation, gene silencing, DNA replication and repair. However, its role in pancreatic cancer has seldom been discussed. In the present study, we silenced CBX3 expression in pancreatic cancer cell lines and identified the positive roles of CBX3 in cancer cell proliferation. Furthermore, we demonstrated that silencing CBX3 in pancreatic cancer cells inhibited aerobic glycolysis, the basis for providing cancer cells with building blocks for macromolecule synthesis and ATP that required. To search for the underlying molecular mechanism, we turned to examine the impact of CBX3 on the expression of FBP1, a negative regulator of aerobic glycolysis in pancreatic cancer and indicated that CBX3 negatively regulated FBP1 expression. Silencing FBP1 expression attenuated the decrease in glycolytic capacity that caused by CBX3 knockdown in pancreatic cancer cells. Taken together, these data reveal that CBX3 serves as a positive regulator of aerobic glycolysis via suppressing of the FBP1 in pancreatic cancer cells. Disrupting the CBX3-FBP1 signaling axis would be effective to treat pancreatic cancer and prevent aerobic glycolysis.

Energy stress-induced lncRNA HAND2-AS1 represses HIF1α-mediated energy metabolism and inhibits osteosarcoma progression

During recent years, long noncoding RNAs (lncRNAs) have been recognized as key regulators in the development and progression of human cancers, however, their roles in osteosarcoma metabolism are still not well understood. The present study aims to investigate the expression profiles and potential modulation of specific lncRNA(s) in osteosarcoma metabolism. The high-throughput Hiseq sequencing was performed to screen for abnormally expressed lncRNAs in osteosarcoma cells cultured under glucose starvation condition, and lncRNA HAND2-AS1 was eventually identified as one that was significantly up-regulated when compared with normal cultured cells. Mechanistic investigations indicated that knockdown of HAND2-AS1 abrogated the energy stress-induced effect on cell apoptosis and proliferation, and promoted osteosarcoma progression. Moreover, knockdown of HAND2-AS1 promoted glucose uptake, lactate production, and the expression level of a serious of enzymes that involved in energy metabolism. Subsequently, RNA pull-down and RNA immuneprecipitation revealed that, upon energy stress, HAND2-AS1 regulated osteosarcoma metabolism through sequestering FBP1 from binding to HIF1α, thereby releasing HIF1α expression and promoting the protein level. Taken together, our integrated approach reveals a regulatory mechanism by lncRNA HAND2-AS1 to control energy metabolism and tumor development in osteosarcoma. Thus, HAND2-AS1 may be a potential biomarker and therapeutic target for the repression of osteosarcoma metabolism.

Increased miR-21a provides metabolic advantages through suppression of FBP1 expression in non-small cell lung cancer cells

Lung cancer is the most common solid tumor and the leading cause of cancer-related mortality worldwide. miR-21 is one of the most commonly observed aberrant miRNAs in human cancers. However, the biological roles of miR-21 in glucose metabolism of non-small cell lung cancer (NSCLC) cells remain unknown. In the present study, our findings demonstrated that miR-21 promoted glucose uptake and increased TXNIP expression. miR-21 increased lactate generation and decreased oxygen consumption in NSCLC cells. Moreover, we found that miR-21 promoted glycolysis and decreased OXPHOS. Mechanistically, fructose-1,6-biphosphatase (FBP1) was a direct target of miR-21 and observed a negative correlation between miR-21 and FBP1 in NSCLC samples. Restoring FBP1 expression reversed the effects induced by miR-21 overexpression in NSCLC cells. Together, our findings suggest the critical role of miR-21 in glucose metabolism through suppression of FBP1 in NSCLC cells. miR-21 may be a potential target of NSCLC treatment.

The anticipating value of PLK1 for diagnosis, progress and prognosis and its prospective mechanism in gastric cancer: a comprehensive investigation based on high-throughput data and immunohistochemical validation

Polo-like kinase 1 (PLK1) is a multi-functional protein and its aberrant expression is a driver of cancerous transformation and progression. To increase our understanding of the clinical value and potential molecular mechanism of PLK1 in gastric cancer (GC), we performed this comprehensive investigation. A total of 25 datasets and 12 publications were finally incorporated. Additional immunohistochemistry was conducted to validate the expression pattern of PLK1 in GC. The pooled standard mean deviation (SMD) indicated that PLK1 mRNA was up-regulated in GC (SMD=1.21, 95% CI: 0.65-1.77, P< 0.001). Similarly, the pooled odds ratio (OR) revealed that PLK1 protein was overexpressed in GC compared with normal gastric tissue (OR=12.12, 95% CI: 5.41-27.16, P<0.001). The area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve was 0.86. Furthermore, our results demonstrated that GC patients with PLK1 overexpression were significantly associated with unfavorable overall survival (HR =1.54, 95% CI: 1.30–1.83, P<0.001), lymph node metastasis (OR = 1.78, 95% CI: 1.13–2.80, P=0.013) and advanced TNM stage (OR=1.48, 95% CI: 1.02-2.15, P=0.038). Altogether, 100 similar genes were identified by Gene Expression Profiling Interactive Analysis (GEPIA) and further with gene-set enrichment analysis. These genes were related to gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways relevant to the cell cycle. Gene set enrichment analysis (GSEA) indicated that PLK1 is associated with various cancer-related pathways. Collectively, this study suggests that PLK1 overexpression could play vital roles in the carcinogenesis and deterioration of GC via regulating tumor-related pathways.

Metabolic reprogramming and epithelial-to-mesenchymal transition in cancer

Several lines of evidence indicate that during transformation epithelial cancer cells can acquire mesenchymal features via a process called epithelial-to-mesenchymal transition (EMT). This process endows cancer cells with increased invasive and migratory capacity, enabling tumour dissemination and metastasis. EMT is associated with a complex metabolic reprogramming, orchestrated by EMT transcription factors, which support the energy requirements of increased motility and growth in harsh environmental conditions. The discovery that mutations in metabolic genes such as FH, SDH and IDH activate EMT provided further evidence that EMT and metabolism are intertwined. In this review, we discuss the role of EMT in cancer and the underpinning metabolic reprogramming. We also put forward the hypothesis that, by altering chromatin structure and function, metabolic pathways engaged by EMT are necessary for its full activation.