Regulation of glucose uptake in lymphoma cell lines by c-MYC- and PI3K-dependent signaling pathways and impact of glycolytic pathways on cell viability

PI3K-dependent reprogramming of hexokinase isoforms controls glucose metabolism and functional responses of B lymphocytes

B lymphocyte activation triggers metabolic reprogramming essential for B cell differentiation and mounting a healthy immune response. Here, we investigate the regulation and function of glucose-phosphorylating enzyme hexokinase 2 (HK2) in B cells. We report that both activation-dependent expression and mitochondrial localization of HK2 are regulated by the phosphatidylinositol 3-kinase (PI3K) signaling pathway. B cell-specific deletion of HK2 in mice caused mild perturbations in B cell development. HK2-deficient B cells show impaired functional responses in vitro and adapt to become less dependent on glucose and more dependent on glutamine. HK2 deficiency impairs glycolysis, alters metabolite profiles, and alters flux of labeled glucose carbons into downstream pathways. Upon immunization, HK2-deficient mice exhibit impaired germinal center, plasmablast, and antibody responses. HK2 expression in primary human chronic lymphocytic leukemia (CLL) cells was associated with recent proliferation and could be reduced by PI3K inhibition. Our study implicates PI3K-dependent modulation of HK2 in B cell metabolic reprogramming.

Metabolic reprogramming and immune evasion: the interplay in the tumor microenvironment

Tumor cells possess complex immune evasion mechanisms to evade immune system attacks, primarily through metabolic reprogramming, which significantly alters the tumor microenvironment (TME) to modulate immune cell functions. When a tumor is sufficiently immunogenic, it can activate cytotoxic T-cells to target and destroy it. However, tumors adapt by manipulating their metabolic pathways, particularly glucose, amino acid, and lipid metabolism, to create an immunosuppressive TME that promotes immune escape. These metabolic alterations impact the function and differentiation of non-tumor cells within the TME, such as inhibiting effector T-cell activity while expanding regulatory T-cells and myeloid-derived suppressor cells. Additionally, these changes lead to an imbalance in cytokine and chemokine secretion, further enhancing the immunosuppressive landscape. Emerging research is increasingly focusing on the regulatory roles of non-tumor cells within the TME, evaluating how their reprogrammed glucose, amino acid, and lipid metabolism influence their functional changes and ultimately aid in tumor immune evasion. Despite our incomplete understanding of the intricate metabolic interactions between tumor and non-tumor cells, the connection between these elements presents significant challenges for cancer immunotherapy. This review highlights the impact of altered glucose, amino acid, and lipid metabolism in the TME on the metabolism and function of non-tumor cells, providing new insights that could facilitate the development of novel cancer immunotherapies.

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

Quantitative PET-based biomarkers in lymphoma: getting ready for primetime

The use of functional quantitative biomarkers extracted from routine PET-CT scans to characterize clinical responses in patients with lymphoma is gaining increased attention, and these biomarkers can outperform established clinical risk factors. Total metabolic tumour volume enables individualized estimation of survival outcomes in patients with lymphoma and has shown the potential to predict response to therapy suitable for  risk-adapted treatment approaches in clinical trials. The deployment of machine learning tools in molecular imaging research can assist in recognizing complex patterns and, with image classification, in tumour identification and segmentation of data from PET-CT scans. Initial studies using fully automated approaches to calculate metabolic tumour volume and other PET-based biomarkers have demonstrated appropriate correlation with calculations from experts, warranting further testing in large-scale studies. The extraction of computer-based quantitative tumour characterization through radiomics can provide a comprehensive view of phenotypic heterogeneity that better captures the molecular and functional features of the disease. Additionally, radiomics can be integrated with genomic data to provide more accurate prognostic information. Further improvements in PET-based biomarkers are imminent, although their incorporation into clinical decision-making currently has methodological shortcomings that need to be addressed with confirmatory prospective validation in selected patient populations. In this Review, we discuss the current knowledge, challenges and opportunities in the integration of quantitative PET-based biomarkers in clinical trials and the routine management of patients with lymphoma.

Metabolic Reprogramming and Potential Therapeutic Targets in Lymphoma

Lymphoma is a heterogeneous group of diseases that often require their metabolism program to fulfill the demand of cell proliferation. Features of metabolism in lymphoma cells include high glucose uptake, deregulated expression of enzymes related to glycolysis, dual capacity for glycolytic and oxidative metabolism, elevated glutamine metabolism, and fatty acid synthesis. These aberrant metabolic changes lead to tumorigenesis, disease progression, and resistance to lymphoma chemotherapy. This metabolic reprogramming, including glucose, nucleic acid, fatty acid, and amino acid metabolism, is a dynamic process caused not only by genetic and epigenetic changes, but also by changes in the microenvironment affected by viral infections. Notably, some critical metabolic enzymes and metabolites may play vital roles in lymphomagenesis and progression. Recent studies have uncovered that metabolic pathways might have clinical impacts on the diagnosis, characterization, and treatment of lymphoma subtypes. However, determining the clinical relevance of biomarkers and therapeutic targets related to lymphoma metabolism is still challenging. In this review, we systematically summarize current studies on metabolism reprogramming in lymphoma, and we mainly focus on disorders of glucose, amino acids, and lipid metabolisms, as well as dysregulation of molecules in metabolic pathways, oncometabolites, and potential metabolic biomarkers. We then discuss strategies directly or indirectly for those potential therapeutic targets. Finally, we prospect the future directions of lymphoma treatment on metabolic reprogramming.

Gold nanoparticles inhibit tumor growth via targeting the Warburg effect in a c-Myc-dependent way

Gold nanoparticles (AuNPs) are prospective tools for nano-based medicine that can directly target cellular biological processes to influence cell fate and function. Studies have revealed the essential role of AuNPs in metabolic remodeling for macrophage polarization. Nevertheless, as a hallmark of cancer cells, metabolic changes in tumor cells in response to AuNPs have not yet been reported. In the present study, polymer- and folate-conjugated AuNPs with satisfactory biocompatibility and tumor-targeting activity were synthesized to investigate their underlying roles in tumor metabolism. Tumor cells were significantly suppressed by AuNPs in vitro and in vivo, with little cytotoxicity in non-tumor cells. Subcellular localization showed that AuNPs localized in the mitochondria of tumor cells and impaired their structure and function, leading to excessive oxidative stress and mitochondrial apoptosis. Metabolic stress, with decreased glycolysis and insufficient nutrients, was also caused by AuNPs exposure in tumor cells. Mechanistically, the key enzymes (GLUT1 and HK2) for glycolysis modulation were remarkably reduced by AuNPs in a c-Myc-dependent manner. The present study demonstrated a new mechanism for AuNPs in the inhibition of tumor growth, that is, via directly targeting glycolysis and depriving energy. These findings provide new strategies for the design of nano-based medicines and anti-glycolytic therapeutics to inhibit the development of malignant tumors. STATEMENT OF SIGNIFICANCE: Gold nanoparticles (AuNPs) have acquired ever-increasing interest for applications in cancer treatment and diagnosis due to their high biosafety and facile surface modification. Recent studies have shown that AuNPs can work as active agents to directly target the cellular processes and harbor antitumor properties, while the underlying mechanisms remain largely unknown. From the present findings, the stabilized AuNPs showed direct inhibition effects on tumor growth by glycolysis inhibition and energy deprivation. These results provide new insights of AuNPs for tumor treatments, which will further contribute to the development of promising nano-based medicines and anti-glycolytic therapies.

Metabolomics: A New Era in the Diagnosis or Prognosis of B-Cell Non-Hodgkin's Lymphoma

A wide range of histological as well as clinical properties are exhibited by B-cell non-Hodgkin's lymphomas. These properties could make the diagnostics process complicated. The diagnosis of lymphomas at an initial stage is essential because early remedial actions taken against destructive subtypes are commonly deliberated as successful and restorative. Therefore, better protective action is needed to improve the condition of those patients who are extensively affected by cancer when diagnosed for the first time. The development of new and efficient methods for early detection of cancer has become crucial nowadays. Biomarkers are urgently needed for diagnosing B-cell non-Hodgkin's lymphoma and assessing the severity of the disease and its prognosis. New possibilities are now open for diagnosing cancer with the help of metabolomics. The study of all the metabolites synthesised in the human body is called "metabolomics." A patient's phenotype is directly linked with metabolomics, which can help in providing some clinically beneficial biomarkers and is applied in the diagnostics of B-cell non-Hodgkin's lymphoma. In cancer research, it can analyse the cancerous metabolome to identify the metabolic biomarkers. This review provides an understanding of B-cell non-Hodgkin's lymphoma metabolism and its applications in medical diagnostics. A description of the workflow based on metabolomics is also provided, along with the benefits and drawbacks of various techniques. The use of predictive metabolic biomarkers for the diagnosis and prognosis of B-cell non-Hodgkin's lymphoma is also explored. Thus, we can say that abnormalities related to metabolic processes can occur in a vast range of B-cell non-Hodgkin's lymphomas. The metabolic biomarkers could only be discovered and identified as innovative therapeutic objects if we explored and researched them. In the near future, the innovations involving metabolomics could prove fruitful for predicting outcomes and bringing out novel remedial approaches.

Altered serum lipid levels are associated with prognosis of diffuse large B cell lymphoma and influenced by utility of rituximab

Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and the prognosis of the disease varied. This research aims to investigate the impact of serum lipid level on the outcome of DLBCL patients and their interaction with rituximab (RTX). Data of newly diagnosed DLBCL in the third affiliated hospital of Soochow University were retrospectively collected. Baseline serum lipid levels, clinical data, and survival information were simultaneously recorded. Data of healthy controls were collected with age matching. Serum lipid levels significantly differed for the patients. All were transformed into categorical variables for the analysis of survival. During a median follow-up of 58 months, 32.8% patients died. Univariate analysis revealed all serum lipid indicators were associated with overall survival (OS); all except for total cholesterol (TC) and apolipoprotein B (apoB) showed significant impact on progression-free survival (PFS). Multivariable analysis confirmed the adverse effect of triglyceride (TG) on PFS (P = 0.013) and favorable impact of high-density lipoprotein (HDL) on OS (P = 0.003). For cases treated without RTX, apolipoprotein A (apoA) had independent favorable effect on both PFS (P = 0.004) and OS (P = 0.001). Comparably, for patients who received RTX, HDL showed remarkably predictive value of PFS (P = 0.011) and OS (P = 0.019). In conclusion, the abnormal serum lipids occurred throughout the course of DLBCL, and the associations of serum lipids and the prognosis of the disease were interfered by RTX. Trial registration: 2022()CL033; June 26, 2022, retrospectively registered.

Expression of fructose-1,6-bisphosphatase 1 is associated with [18F]FDG uptake and prognosis in patients with mesial temporal lobe epilepsy

OBJECTIVES

To determine whether fructose-1,6-bisphosphatase 1 (FBP1) expression is associated with [¹⁸F]FDG PET uptake and postsurgical outcomes in patients with mesial temporal lobe epilepsy (mTLE) and to investigate whether the molecular mechanism involving gamma-aminobutyric acid type A receptor (GABA_AR), glucose transporter-3 (GLUT-3), and hexokinase-II (HK-II).

METHODS

Forty-three patients with mTLE underwent [¹⁸F]FDG PET/CT. Patients were divided into Ia (Engel class Ia) and non-Ia (Engel class Ib-IV) groups according to more than 1 year of follow-up after surgery. The maximum standard uptake value (SUV_max) and asymmetry index (AI) of hippocampus were measured. The relationship among the SUV_max, AI, prognosis, and FBP1 expression was analyzed. A lithium-pilocarpine acute mTLE rat model was subjected to [¹⁸F]FDG micro-PET/CT. Hippocampal SUV_max and FBP1, GABA_AR, GLUT-3, and HK-II expression were analyzed.

RESULTS

SUV_max was higher in the Ia group than in the non-Ia group (7.31 ± 0.97 vs. 6.56 ± 0.96, p < 0.05) and FBP1 expression was lower in the Ia group (0.24 ± 0.03 vs. 0.27 ± 0.03, p < 0.01). FBP1 expression was negatively associated with SUV_max and AI (p < 0.01). In mTLE rats, the hippocampal FBP1 increased (0.26 ± 0.00 vs. 0.17 ± 0.00, p < 0.0001), and SUV_max, GLUT-3 and GABA_AR levels decreased significantly (0.73 ± 0.12 vs. 1.46 ± 0.23, 0.20 ± 0.01 vs. 0.32 ± 0.05, 0.26 ± 0.02 vs. 0.35 ± 0.02, p < 0.05); no significant difference in HK-II levels was observed. In mTLE patients and rats, FBP1 negatively correlated with SUV_max and GLUT-3 and GABA_AR levels (p < 0.05).

CONCLUSION

FBP1 expression was inversely associated with SUV_max in mTLE, which might inhibit [¹⁸F]FDG uptake by regulating GLUT-3 expression. High FBP1 expression was indicative of low GABA_AR expression and poor prognosis.

KEY POINTS

• It is of paramount importance to explore the deep pathophysiological mechanisms underlying the pathogenesis of mesial temporal lobe epilepsy and find potential therapeutic targets. • [¹⁸F]FDG PET has demonstrated low metabolism in epileptic regions during the interictal period, and hypometabolism may be associated with prognosis, but the pathomechanism of this association remains uncertain. • Our results support the possibility that FBP1 might be simultaneously involved in the regulation of glucose metabolism levels and the excitability of neurons and suggest that targeting FBP1 may be a viable strategy in the diagnosis and treatment of mesial temporal lobe epilepsy.

Loss of MiR-155 Sensitizes FLT3-ITD+AML to Chemotherapy and FLT3 Inhibitors via Glycolysis Blocking by Targeting PIK3R1

FLT3 tyrosine kinase inhibitors in combination with chemotherapy have shown some success in patients with FLT3 mutations. But a variety of mechanisms have led to the rapid resistance to the treatment. One of the most prominent is the metabolic alteration on aerobic glycolysis. We aim to explore the role of a high expressing microRNA, miR-155, in mediating resistance to chemotherapy and FLT3 inhibitor treatment. The deep sequencing data mining revealed the connection between glycolysis and drug resistance. MV411 cells with miR-155 knockout (KO) not only had increased sensitivity to FLT3 inhibitors but also Adriamycin (ADM) treatment. When combined with glycolysis inhibition the treatment response in MV411 cells further increased. Whereas in miR-155 KO cells, a lower glucose consumption level and lactic acid level were observed, and western blotting showed a decreased expression of key enzymes in glycolysis pathways. A negative correlation between PIK3R1 and miR-155 level can be observed in the sequencing data from FLT3-ITD⁺ AML patients. Moreover, luciferase reporter assay revealed that the 3'UTR of PIK3R1 mRNA can interact with the seed sequence of miR-155-5p. In conclusion, the loss of miR-155 increased treatment sensitivity to both chemotherapy and FLT3 inhibitors in FLT3-ITD⁺ AML cells via glycolysis blocking by targeting PIK3R1.

Metabolism in Hematopoiesis and Its Malignancy

Hematopoietic stem cells (HSCs) are multipotent stem cells that can self-renew and generate all blood cells of different lineages. The system is under tight control in order to maintain a precise equilibrium of the HSC pool and the effective production of mature blood cells to support various biological activities. Cell metabolism can regulate different molecular activities, such as epigenetic modification and cell cycle regulation, and subsequently affects the function and maintenance of HSC. Upon malignant transformation, oncogenic drivers in malignant hematopoietic cells can remodel the metabolic pathways for supporting the oncogenic growth. The dysregulation of metabolism results in oncogene addiction, implying the development of malignancy-specific metabolism-targeted therapy. In this chapter, we will discuss the significance of different metabolic pathways in hematopoiesis, specifically, the distinctive metabolic dependency in hematopoietic malignancies and potential metabolic therapy.

Expression of glucose transporter-1 in follicular lymphoma affected tumor-infiltrating immunocytes and was related to progression of disease within 24 months

OBJECTIVE

Follicular lymphoma (FL) occurring progression within 24 months (POD24) after initial immunochemotherapy has poor prognosis. GLUT1 affects glycolysis within tumor microenvironment (TME) and promotes tumor progression. However, its specific mediated mechanism remains unclear in FL.

METHODS

Baseline GLUT1 expression, infiltrations of M2 macrophage, and CD8+ T-cells were assessed by immunohistochemistry in FL with POD24 and long-term remission respectively. The spatial features of TME were assessed by MIBI-TOF and proteomics. Predictive immunophenotypes for POD24 occurrence was analyzed by random forest algorithm. The lactate production and the induction of M2 macrophages were detected when GLUT1 was transfected or knocked down in DOHH2. The activation of PI3K/Akt/mTOR signaling in DOHH2 and WSU-FSCCL cells co-cultured with induced inhibitory immunocytes was tracked by western blotting.

RESULTS

The FL with POD24 exhibited higher baseline GLUT1 expression and increased infiltration of various inhibitory immunocytes. Spatial signatures of 69 immunophenotypes could predict POD24 occurrence. The activation of PI3K/ Akt /mTOR signaling pathway was not significant in both groups. The supernatant of DOHH2-GLUT1 cells which had more lactate content could induce more M2-type macrophages than that of DOHH2/siRNA GLUT1 cells. When co-cultured with exhausted CD8+ T cells, M2-type macrophages and Tregs, compared with WSU-FSCCL cells, DOHH2 cells with high GLUT1 expression induced more M2-type macrophages and was triggered activation of PI3K/ Akt /mTOR signaling pathway.

CONCLUSION

Tumor cells overexpressing GLUT1 could domesticate immunocytes to form an immunosuppressive TME, which promotes occurrence of POD24 and gradually activates PI3K/ Akt /mTOR pathway of tumor cells in FL.

SIGNIFICANCE

Tumor cells overexpressing GLUT1 could domesticate immunocytes to form an immunosuppressive microenvironment, which in turn promoted the growth of tumor cells and was related to the progression of disease within 24 months in FL. Suppressive immunocytes gradually activated PI3K/ Akt /mTOR pathway of tumor cells in later stage. Distinguishing spatial features of immunocytes could well predict POD24 occurrence, hoping to benefit these patients from early anti-metabolism therapy based on GLUT1 in the future.

Identification of oncogenic signaling pathways associated with the dimorphic metabolic dysregulations in gastric cancer subtypes

Metabolic dysregulations have been identified as intrinsic hallmarks of cancer cells. Investigations of altered metabolic processes, in the context of the associated oncogenic signaling pathways are expected to pave way for the development of targeted cancer therapeutics. We have recently identified the enrichment of glucose and glutamine metabolism in a subset of intestinal subtype gastric tumors at the level of expression of genes, gene sets and the occurrence of metabolites. On the other hand, glucose transport, glucan and fatty acid metabolism were enriched in a subset of diffuse subtype gastric tumors. In the current study, along with glucose metabolism, mTOR, HSP90, MYC, E2F, P53 and proteasome pathways were found enriched in a subset of intestinal subtype and a part of MSI subtype gastric tumors. On the other hand, along with fatty acid metabolism, the oncogenic pathway KRAS was found to be enriched in a subset of GS tumors among diffuse subtype gastric tumors. Thus, oncogenic signaling pathways associated with two distinct metabolic rewiring which differentially occurs between major gastric cancer subtypes were identified. These pathways seem the potential targets to differentially target these gastric cancer subtypes. Exploratory integrative genomic analyses reveal HSP90 inhibitors, AKT/mTOR inhibitors, and cell cycle inhibitors as potential agents to target the gastric tumors with the rewired glucose metabolism and MEK/MAPK inhibitors as suitable drug candidates to target the diffuse subtype tumors with the dysregulated fatty acid metabolism. This observation would pave way for the selective and targeted use of signaling pathway modulators for targeted and stratified gastric cancer therapeutics.

SIGNALING PATHWAYS THAT DRIVE 18F-FDG ACCUMULATION IN CANCER

2-¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) measures glucose consumption and is an integral part of cancer management. Most cancer types upregulate their glucose consumption, yielding elevated ¹⁸F-FDG PET accumulation in those cancer cells. The biochemical pathway through which ¹⁸F-FDG accumulates in cancer cells is well-established. However, beyond well-known regulators such as c-Myc, PI3K/Akt, and HIF1α, the proteins and signaling pathways that cancer cells modulate to activate the facilitated glucose transporters (GLUTs) and hexokinase enzymes that drive elevated ¹⁸F-FDG accumulation are less well-understood. Understanding these signaling pathways could yield additional biological insights from ¹⁸F-FDG PET scans and could suggest new uses of ¹⁸F-FDG PET in the management of cancer. Work over the past five years, building on studies from years prior, has identified new proteins and signaling pathways that drive glucose consumption in cancer. Here we review these recent studies and discuss current limitations to our understanding of glucose consumption in cancer.

The Wnt Signaling Pathway Inhibitors Improve the Therapeutic Activity of Glycolysis Modulators against Tongue Cancer Cells

Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the effects of the combinatorial use of glycolysis and Wnt signaling inhibitors on viability, cytotoxicity, apoptosis induction, cell cycle distribution and the glycolytic activity of tongue carcinoma cells. CAL 27, SCC-25 and BICR 22 tongue cancer cell lines were used. Cells were treated with inhibitors of glycolysis (2-deoxyglucose and lonidamine) and of Wnt signaling (PRI-724 and IWP-O1). The effects of the compounds on cell viability and cytotoxicity were evaluated with MTS and CellTox Green tests, respectively. Apoptosis was evaluated by MitoPotential Dye staining and cell cycle distribution by staining with propidium iodide, followed by flow cytometric cell analysis. Glucose and lactate concentrations in a culture medium were evaluated luminometrically. Combinations of 2-deoxyglucose and lonidamine with Wnt pathway inhibitors were similarly effective in the impairment of oral cancer cells’ survival. However, the inhibition of the canonical Wnt pathway by PRI-724 was more beneficial, based on the glycolytic activity of the cells. The results point to the therapeutic potential of the combination of low concentrations of glycolytic modulators with Wnt pathway inhibitors in oral cancer cells.

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.

2-Deoxy-D-glucose impedes T cell-induced apoptosis of keratinocytes in oral lichen planus

Oral lichen planus (OLP) is a T cell–mediated immunoinflammatory disease. Glycolysis plays an essential role in T‐cell immune responses. Blocking glycolytic pathway in activated T cells represents a therapeutic strategy for restraint of immunologic process in autoimmune disorders. 2‐Deoxy‐D‐glucose (2‐DG) has been widely used to probe into glycolysis in immune cells. This study was aimed to explore the role of glycolysis inhibition by 2‐DG on regulating immune responses of OLP‐derived T cells. We observed that lactic dehydrogenase A (LDHA) expression was elevated in OLP lesions and local T cells. 2‐DG inhibited the expression of LDHA, p‐mTOR, Hif1α and PLD2 in T cells; meanwhile, it decreased proliferation and increased apoptosis of T cells. T cells treated by 2‐DG showed lower LDHA expression and elevated apoptosis, resulting in a reduced apoptotic population of keratinocytes that were co‐cultured with them, which was related to the decreased levels of IFN‐γ in co‐culture system. Rapamycin enhanced the effects of 2‐DG on immune responses between T cells and keratinocytes. Thus, these findings indicated that OLP‐derived T cells might be highly dependent upon high glycolysis for proliferation, and 2‐DG treatment combined with rapamycin might be an option to alleviate T‐cell responses, contributing to reducing apoptosis of keratinocytes.

The combinatorial inhibition of Wnt signaling and Akt kinase is beneficial for reducing the survival and glycolytic activity of tongue cancer cells

BACKGROUND

Wnt signaling is important in the development of head and neck squamous cell carcinomas (HNSCC); however, Wnt pathway inhibitors lack satisfactory potency when used in monotherapy. The aim of this study was to assess the effects of the combinations of Wnt-signaling inhibitors and the inhibitor of Akt kinase on the survival and glycolytic activity of tongue carcinoma cells.

METHODS

CAL27, SCC-25, and BICR22 tongue cancer cell lines were used. Cells were treated with Wnt signaling (PRI-724 and IWP-O1) and Akt-kinase inhibitors. The effect of the chemicals on cell viability and cytotoxicity were evaluated by MTS and CellTox Green assays, respectively. Cell cycle distribution was analyzed cytometrically after propidium iodide staining. Annexin V binding to externalized phosphatidylserine and analysis of mitochondrial potential allowed the assessment of apoptosis. Glucose uptake and lactate release were evaluated luminometrically. Additionally, the viability of cells in spheroids was analyzed based on ATP content.

RESULTS

The Akt-kinase inhibitor showed significant cytotoxicity toward primary cancer cells. Moreover, its pro-apoptotic effects were enhanced by Wnt-pathway inhibitors. The activity of Akt inhibitor was even higher (by twofold) in 3D spheroids in comparison to cells grown in monolayer. The synergistic reduction in the growth of spheroids was observed between Akt inhibitor and IWP-O1. Reduced glucose consumption may play a part in the combinatorial effects of these chemicals.

CONCLUSION

The results point to the therapeutic potential of the combinatorial use of Wnt inhibitors together with Akt inhibitors in HNSCC.

Identification of a prognostic metabolic gene signature in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a clinically diverse disease. Given the numerous genetic mutations and variations associated with it, a prognostic gene signature that can be related to the overall survival (OS) is a clinical implication. We used the mRNA expression profiles and clinicopathological data of patients with DLBCL from the Gene Expression Omnibus (GEO) database to identify a metabolism-related gene signature. Using LASSO regression analysis, a novel 13-metabolic gene signature was identified to evaluate prognosis. The information gathered was used to construct the nomogram model to improve risk stratification and quantify risk factors for individual patients. We performed gene set enrichment analysis to identify the enriched signalling axes to further understand the underlying biological pathways. The receiver operating characteristic (ROC) curve revealed a satisfactory performance in the training cohorts. The model also showed clinical benefit when compared to the standard prognostic factors (P < .05) in validation cohorts. This study aimed to combine metabolic dysregulation with clinical features of patients with DLBCL to generate a prognostic model that might not only indicate the value of the metabolic microenvironment for prognostic stratification but also improve the decision-making during individual therapy.

mTOR Overcomes Multiple Metabolic Restrictions to Enable HIV-1 Reverse Transcription and Intracellular Transport

Cellular metabolism governs the susceptibility of CD4 T cells to HIV-1 infection. Multiple early post-fusion steps of HIV-1 replication are restricted in resting peripheral blood CD4 T cells; however, molecular mechanisms that underlie metabolic control of these steps remain undefined. Here, we show that mTOR activity following T cell stimulatory signals overcomes metabolic restrictions in these cells by enabling the expansion of dNTPs to fuel HIV-1 reverse transcription (RT), as well as increasing acetyl-CoA to stabilize microtubules that transport RT products. We find that catalytic mTOR inhibition diminishes the expansion of pools of both of these metabolites by limiting glucose and glutamine utilization in several pathways, thereby suppressing HIV-1 infection. We demonstrate how mTOR-coordinated biosyntheses enable the early steps of HIV-1 replication, add metabolic mechanisms by which mTOR inhibitors block HIV-1, and identify some metabolic modules downstream of mTOR as druggable targets for HIV-1 inhibition.

Mitochondrial Bioenergetics at the Onset of Drug Resistance in Hematological Malignancies: An Overview

The combined derangements in mitochondria network, function and dynamics can affect metabolism and ATP production, redox homeostasis and apoptosis triggering, contributing to cancer development in many different complex ways. In hematological malignancies, there is a strong relationship between cellular metabolism, mitochondrial bioenergetics, interconnections with supportive microenvironment and drug resistance. Lymphoma and chronic lymphocytic leukemia cells, e.g., adapt to intrinsic oxidative stress by increasing mitochondrial biogenesis. In other hematological disorders such as myeloma, on the contrary, bioenergetics changes, associated to increased mitochondrial fitness, derive from the adaptive response to drug-induced stress. In the bone marrow niche, a reverse Warburg effect has been recently described, consisting in metabolic changes occurring in stromal cells in the attempt to metabolically support adjacent cancer cells. Moreover, a physiological dynamic, based on mitochondria transfer, between tumor cells and their supporting stromal microenvironment has been described to sustain oxidative stress associated to proteostasis maintenance in multiple myeloma and leukemia. Increased mitochondrial biogenesis of tumor cells associated to acquisition of new mitochondria transferred by mesenchymal stromal cells results in augmented ATP production through increased oxidative phosphorylation (OX-PHOS), higher drug resistance, and resurgence after treatment. Accordingly, targeting mitochondrial biogenesis, electron transfer, mitochondrial DNA replication, or mitochondrial fatty acid transport increases therapy efficacy. In this review, we summarize selected examples of the mitochondrial derangements in hematological malignancies, which provide metabolic adaptation and apoptosis resistance, also supported by the crosstalk with tumor microenvironment. This field promises a rational design to improve target-therapy including the metabolic phenotype.

Power of two: combination of therapeutic approaches involving glucose transporter (GLUT) inhibitors to combat cancer

Cancer research of the Warburg effect, a hallmark metabolic alteration in tumors, focused attention on glucose metabolism whose targeting uncovered several agents with promising anticancer effects at the preclinical level. These agents' monotherapy points to their potential as adjuvant combination therapy to existing standard chemotherapy in human trials. Accordingly, several studies on combining glucose transporter (GLUT) inhibitors with chemotherapeutic agents, such as doxorubicin, paclitaxel, and cytarabine, showed synergistic or additive anticancer effects, reduced chemo-, radio-, and immuno-resistance, and reduced toxicity due to lowering the therapeutic doses required for desired chemotherapeutic effects, as compared with monotherapy. The combinations have been specifically effective in treating cancer glycolytic phenotypes, such as pancreatic and breast cancers. Even combining GLUT inhibitors with other glycolytic inhibitors and energy restriction mimetics seems worthwhile. Though combination clinical trials are in the early phase, initial results are intriguing. The various types of GLUTs, their role in cancer progression, GLUT inhibitors, and their anticancer mechanism of action have been reviewed several times. However, utilizing GLUT inhibitors as combination therapeutics has received little attention. We consider GLUT inhibitors agents that directly affect glucose transporters by binding to them or indirectly alter glucose transport by changing the transporters' expression level. This review mainly focuses on summarizing the effects of various combinations of GLUT inhibitors with other anticancer agents and providing a perspective on the current status.

Flavonoids against the Warburg phenotype-concepts of predictive, preventive and personalised medicine to cut the Gordian knot of cancer cell metabolism

The Warburg effect is characterised by increased glucose uptake and lactate secretion in cancer cells resulting from metabolic transformation in tumour tissue. The corresponding molecular pathways switch from oxidative phosphorylation to aerobic glycolysis, due to changes in glucose degradation mechanisms known as the 'Warburg reprogramming' of cancer cells. Key glycolytic enzymes, glucose transporters and transcription factors involved in the Warburg transformation are frequently dysregulated during carcinogenesis considered as promising diagnostic and prognostic markers as well as treatment targets. Flavonoids are molecules with pleiotropic activities. The metabolism-regulating anticancer effects of flavonoids are broadly demonstrated in preclinical studies. Flavonoids modulate key pathways involved in the Warburg phenotype including but not limited to PKM2, HK2, GLUT1 and HIF-1. The corresponding molecular mechanisms and clinical relevance of 'anti-Warburg' effects of flavonoids are discussed in this review article. The most prominent examples are provided for the potential application of targeted 'anti-Warburg' measures in cancer management. Individualised profiling and patient stratification are presented as powerful tools for implementing targeted 'anti-Warburg' measures in the context of predictive, preventive and personalised medicine.

Targeting lactate dehydrogenase A (LDHA) exerts antileukemic effects on T-cell acute lymphoblastic leukemia

Background

T‐cell acute lymphoblastic leukemia (T‐ALL) is an uncommon and aggressive subtype of acute lymphoblastic leukemia (ALL). In the serum of T‐ALL patients, the activity of lactate dehydrogenase A (LDHA) is increased. We proposed that targeting LDHA may be a potential strategy to improve T‐ALL outcomes. The current study was conducted to investigate the antileukemic effect of LDHA gene‐targeting treatment on T‐ALL and the underlying molecular mechanism.

Methods

Primary T‐ALL cell lines Jurkat and DU528 were treated with the LDH inhibitor oxamate. MTT, colony formation, apoptosis, and cell cycle assays were performed to investigate the effects of oxamate on T‐ALL cells. Quantitative real‐time PCR (qPCR) and Western blotting analyses were applied to determine the related signaling pathways. A mitochondrial reactive oxygen species (ROS) assay was performed to evaluate ROS production after T‐ALL cells were treated with oxamate. A T‐ALL transgenic zebrafish model with LDHA gene knockdown was established using CRISPR/Cas9 gene‐editing technology, and then TUNEL, Western blotting, and T‐ALL tumor progression analyses were conducted to investigate the effects of LDHA gene knockdown on T‐ALL transgenic zebrafish.

Results

Oxamate significantly inhibited proliferation and induced apoptosis of Jurkat and DU528 cells. It also arrested Jurkat and DU528 cells in G0/G1 phase and stimulated ROS production (all P < 0.001). Blocking LDHA significantly decreased the gene and protein expression of c‐Myc, as well as the levels of phosphorylated serine/threonine kinase (AKT) and glycogen synthase kinase 3 beta (GSK‐3β) in the phosphatidylinositol 3′‐kinase (PI3K) signaling pathway. LDHA gene knockdown delayed disease progression and down‐regulated c‐Myc mRNA and protein expression in T‐ALL transgenic zebrafish.

Conclusion

Targeting LDHA exerted an antileukemic effect on T‐ALL, representing a potential strategy for T‐ALL treatment.

[Recombinant methioninase regulates PI3K/Akt/Glut-1 pathway and inhibits aerobic glycolysis to promote apoptosis of gastric cancer cells]

OBJECTIVE

To investigate the molecular mechanism of recombinant methioninase (rMETase) in promoting apoptosis of gastric cancer cells.

METHODS

Gastric cancer SGC-7901 cells were treated with rMETase (final concentration of 1.25 and 2.50 mmmol/L) for 72 h, and the changes in the cell viability were detected using CCK-8 method and the cell morphology changes were observed under an inverted microscope. Plate colony formation assay was used to evaluate colony formation ability of the cells, and flow cytometry was performed to analyze the changes in cell apoptosis and cell cycles. Glucose and lactate levels in the culture medium were determined using a colorimetric method and ATP concentration was detected using a fluorescence microplate reader; Western blotting was used to assess the effect of rMETase on PI3K/Akt pathway, glucose transporter-1 (GLUT-1), glycolysis- related proteins and apoptotic proteins in SGC-7901 cells.

RESULTS

rMETase significantly inhibited the proliferation and clonal formation, promoted cell apoptosis, and induced cell cycle arrest in S phase in SGC-7901 cells (P < 0.05). With the increase of rMETase concentration, the cells showed obviously decreased glucose intake accompanied by decreased glycolysis and ATP concentration (P < 0.001). The results of Western blotting showed that the expressions of PI3K, p-Akt/t-Akt, GLUT-1, and the key glycolytic enzymes HK2, PFKM, LDHA, antiapoptosis protein Bcl-2 were all downregulated and the pro-apoptotic proteins Bax and caspase-3 were up-regulated in response to rMETase treatment in SGC-7901 cells (P < 0.01).

CONCLUSIONS

rMETase can inhibit aerobic glycolysis, induce apoptosis and inhibit the proliferation of SGC-7901 cells by inhibiting the activity of PI3K/Akt/GLUT-1 pathway, suggesting its potential as a therapeutic agent for gastric cancer.

Targeting ERK-Hippo Interplay in Cancer Therapy

Extracellular signal-regulated kinase (ERK) is a part of the mitogen-activated protein kinase (MAPK) signaling pathway which allows the transduction of various cellular signals to final effectors and regulation of elementary cellular processes. Deregulation of the MAPK signaling occurs under many pathological conditions including neurodegenerative disorders, metabolic syndromes and cancers. Targeted inhibition of individual kinases of the MAPK signaling pathway using synthetic compounds represents a promising way to effective anti-cancer therapy. Cross-talk of the MAPK signaling pathway with other proteins and signaling pathways have a crucial impact on clinical outcomes of targeted therapies and plays important role during development of drug resistance in cancers. We discuss cross-talk of the MAPK/ERK signaling pathway with other signaling pathways, in particular interplay with the Hippo/MST pathway. We demonstrate the mechanism of cell death induction shared between MAPK/ERK and Hippo/MST signaling pathways and discuss the potential of combination targeting of these pathways in the development of more effective anti-cancer therapies.

AKT but not MYC promotes reactive oxygen species-mediated cell death in oxidative culture

Oncogenes can create metabolic vulnerabilities in cancer cells. We tested how AKT (herein referring to AKT1) and MYC affect the ability of cells to shift between respiration and glycolysis. Using immortalized mammary epithelial cells, we discovered that constitutively active AKT, but not MYC, induced cell death in galactose culture, where cells rely on oxidative phosphorylation for energy generation. However, the negative effects of AKT were temporary, and AKT-expressing cells recommenced growth after ∼15 days in galactose. To identify the mechanisms regulating AKT-mediated cell death, we used metabolomics and found that AKT-expressing cells that were dying in galactose culture had upregulated glutathione metabolism. Proteomic profiling revealed that AKT-expressing cells dying in galactose also upregulated nonsense-mediated mRNA decay, a marker of sensitivity to oxidative stress. We therefore measured levels of reactive oxygen species (ROS) and discovered that galactose-induced ROS exclusively in cells expressing AKT. Furthermore, ROS were required for galactose-induced death of AKT-expressing cells. We then confirmed that galactose-induced ROS-mediated cell death in breast cancer cells with upregulated AKT signaling. These results demonstrate that AKT but not MYC restricts the flexibility of cancer cells to use oxidative phosphorylation.This article has an associated First Person interview with the first author of the paper.

Influence of Hydrophobic Chains in Nanocarriers on Antitumor Efficacy of Docetaxel Nanoparticles

The composition of amphiphilic nanocarriers can affect the antitumor efficacy of drug-loaded nanoparticles and should be researched systematically. In this paper, to study the influence of hydrophobic chains, an amphiphilic copolymer (PEG₄₅PCL₁₇) and hydrophilic PEG (PEG₄₅) were utilized as nanocarriers to prepare docetaxel-loaded nanoparticles (DTX/PEG₄₅PCL₁₇ nanoparticles and DTX/PEG₄₅ nanoparticles) through an antisolvent precipitation method. The two DTX nanoparticles presented a similar drug loading content of approximately 60% and a sheet-like morphology. During the preparation procedure, the drug loading content affected the morphology of DTX nanoparticles, and the nanocarrier composition influenced the particle size. Compared with DTX/PEG₄₅ nanoparticles, DTX/PEG₄₅PCL₁₇ nanoparticles showed a smaller mean diameter and better in vitro and in vivo antitumor activity. The cytotoxicity of DTX/PEG₄₅PCL₁₇ nanoparticles against 4T1 cells was 1.31 μg mL^-1, 3.4-fold lower than that of DTX/PEG₄₅ nanoparticles. More importantly, DTX/PEG₄₅PCL₁₇ nanoparticles showed significantly higher antitumor activity in vivo, with an inhibition rate over 80%, 1.5-fold higher than that of DTX/PEG₄₅ nanoparticles. Based on these results, antitumor activity appears to be significantly affected by the particle size, which was determined by the composition of the nanocarrier. In summary, to improve antitumor efficacy, the amphiphilic structure should be considered and optimized in the design of nanocarriers.

Phosphoenolpyruvate from Glycolysis and PEPCK Regulate Cancer Cell Fate by Altering Cytosolic Ca2

Changes in phosphoenolpyruvate (PEP) concentrations secondary to variations in glucose availability can regulate calcium signaling in T cells as this metabolite potently inhibits the sarcoplasmic reticulum Ca2+/ATPase pump (SERCA). This regulation is critical to assert immune activation in the tumor as T cells and cancer cells compete for available nutrients. We examined here whether cytosolic calcium and the activation of downstream effector pathways important for tumor biology are influenced by the presence of glucose and/or cataplerosis through the phosphoenolpyruvate carboxykinase (PEPCK) pathway, as both are hypothesized to feed the PEP pool. Our data demonstrate that cellular PEP parallels extracellular glucose in two human colon carcinoma cell lines, HCT-116 and SW480. PEP correlated with cytosolic calcium and NFAT activity, together with transcriptional up-regulation of canonical targets PTGS2 and IL6 that was fully prevented by CsA pre-treatment. Similarly, loading the metabolite directly into the cell increased cytosolic calcium and NFAT activity. PEP-stirred cytosolic calcium was also responsible for the calmodulin (CaM) dependent phosphorylation of c-Myc at Ser62, resulting in increased activity, probably through enhanced stabilization of the protein. Protein expression of several c-Myc targets also correlated with PEP levels. Finally, the participation of PEPCK in this axis was interrogated as it should directly contribute to PEP through cataplerosis from TCA cycle intermediates, especially in glucose starvation conditions. Inhibition of PEPCK activity showed the expected regulation of PEP and calcium levels and consequential downstream modulation of NFAT and c-Myc activities. Collectively, these results suggest that glucose and PEPCK can regulate NFAT and c-Myc activities through their influence on the PEP/Ca2+ axis, advancing a role for PEP as a second messenger communicating metabolism, calcium cell signaling, and tumor biology.

Targeting mTOR and Metabolism in Cancer: Lessons and Innovations

Cancer cells support their growth and proliferation by reprogramming their metabolism in order to gain access to nutrients. Despite the heterogeneity in genetic mutations that lead to tumorigenesis, a common alteration in tumors occurs in pathways that upregulate nutrient acquisition. A central signaling pathway that controls metabolic processes is the mTOR pathway. The elucidation of the regulation and functions of mTOR can be traced to the discovery of the natural compound, rapamycin. Studies using rapamycin have unraveled the role of mTOR in the control of cell growth and metabolism. By sensing the intracellular nutrient status, mTOR orchestrates metabolic reprogramming by controlling nutrient uptake and flux through various metabolic pathways. The central role of mTOR in metabolic rewiring makes it a promising target for cancer therapy. Numerous clinical trials are ongoing to evaluate the efficacy of mTOR inhibition for cancer treatment. Rapamycin analogs have been approved to treat specific types of cancer. Since rapamycin does not fully inhibit mTOR activity, new compounds have been engineered to inhibit the catalytic activity of mTOR to more potently block its functions. Despite highly promising pre-clinical studies, early clinical trial results of these second generation mTOR inhibitors revealed increased toxicity and modest antitumor activity. The plasticity of metabolic processes and seemingly enormous capacity of malignant cells to salvage nutrients through various mechanisms make cancer therapy extremely challenging. Therefore, identifying metabolic vulnerabilities in different types of tumors would present opportunities for rational therapeutic strategies. Understanding how the different sources of nutrients are metabolized not just by the growing tumor but also by other cells from the microenvironment, in particular, immune cells, will also facilitate the design of more sophisticated and effective therapeutic regimen. In this review, we discuss the functions of mTOR in cancer metabolism that have been illuminated from pre-clinical studies. We then review key findings from clinical trials that target mTOR and the lessons we have learned from both pre-clinical and clinical studies that could provide insights on innovative therapeutic strategies, including immunotherapy to target mTOR signaling and the metabolic network in cancer.

Glycolytic enzyme hexokinase II is a putative therapeutic target in B-cell malignant lymphoma

Hexokinase II (HXKII) is a key regulator of glucose metabolism that converts glucose to glucose 6-phosphate. Furthermore, HXKII blocks mitochondria-dependent apoptosis by inhibiting the release of cytochrome c. HXKII overexpression is frequently observed in several types of cancer and confers chemoresistance to cancer cells. In the present study, we found that compared with cell lines generated from diffuse large-B-cell lymphoma (DLBCL) patients, cell lines with features of Burkitt lymphoma have higher levels of HXKII because of the activation of both c-MYC and HIF-1. Under normoxia, HXKII levels were correlated with the growth ability of each B-cell lymphoma cell line. HXKII levels were further enhanced when the B-cell lymphoma cells were cultured under hypoxia. The high levels of HXKII induced by hypoxia conferred cisplatin resistance in all tested B-cell lymphoma cell lines. The HDAC inhibitor panobinostat significantly suppressed HXKII expression under both normoxic and hypoxic conditions. Importantly, panobinostat reversed the anti-lymphoma action of cisplatin, and this effect was diminished by hypoxia. These data suggest that HXKII plays different roles, including in the regulation of glycolysis and inhibition of apoptosis, depending on its expression levels. Furthermore, inhibition of HXKII expression by panobinostat may represent a new and attractive strategy to overcome cisplatin resistance.

Tumor Metabolism as a Regulator of Tumor-Host Interactions in the B-Cell Lymphoma Microenvironment-Fueling Progression and Novel Brakes for Therapy

Tumor metabolism and its specific alterations have become an integral part of understanding functional alterations leading to malignant transformation and maintaining cancer progression. Here, we review the metabolic changes in B-cell neoplasia, focusing on the effects of tumor metabolism on the tumor microenvironment (TME). Particularly, innate and adaptive immune responses are regulated by metabolites in the TME such as lactate. With steadily increasing therapeutic options implicating or utilizing the TME, it has become essential to address the metabolic alterations in B-cell malignancy for therapeutic approaches. In this review, we discuss metabolic alterations of B-cell lymphoma, consequences for currently used therapy regimens, and novel approaches specifically targeting metabolism in the TME.

[Regulation of tumor cell glycometabolism and tumor therapy]

Tumor cells have unique energy metabolism phenomena, namely high glucose absorption, aerobic glycolysis and high lactic acid production, which are characterized by down-regulation of related proteins involved in oxidative metabolism in tumor cells, and up-regulation of glucose transporters and monocarboxylate transporters. Studies have shown that drugs that target tumor cell glucose metabolism have the ability to selectively kill tumor cells, bringing new hope for tumor treatment. Tumor stem cells are considered to be the root cause of tumor recurrence, metastasis and poor prognosis, and their energy metabolism characteristics have not yet been agreed. Studies have shown that reversing the energy metabolism of tumor stem cells can increase their chemosensitivity. This article reviews recent studies on tumor and tumor stem cell glucose metabolism and the opportunities and challenges of tumor treatment through targeting glucose metabolism, which might provide new ideas and opportunities for clinical tumor therapy.

Disturbances in H+ dynamics during environmental carcinogenesis

Despite the improvement of diagnostic methods and anticancer therapeutics, the human population is still facing an increasing incidence of several types of cancers. According to the World Health Organization, this growing trend would be partly linked to our environment, with around 20% of cancers stemming from exposure to environmental contaminants, notably chemicals like polycyclic aromatic hydrocarbons (PAHs). PAHs are widespread pollutants in our environment resulting from incomplete combustion or pyrolysis of organic material, and thus produced by both natural and anthropic sources; notably benzo[a]pyrene (B[a]P), i.e. the prototypical molecule of this family, that can be detected in cigarette smoke, diesel exhaust particles, occupational-related fumes, and grilled food. This molecule is a well-recognized carcinogen belonging to group 1 carcinogens. Indeed, it can target the different steps of the carcinogenic process and all cancer hallmarks. Interestingly, H⁺ dynamics have been described as key parameters for the occurrence of several, if not all, of these hallmarks. However, information regarding the role of such parameters during environmental carcinogenesis is still very scarce. The present review will thus mainly give an overview of the impact of B[a]P on H⁺ dynamics in liver cells, and will show how such alterations might impact different aspects related to the finely-tuned balance between cell death and survival processes, thereby likely favoring environmental carcinogenesis. In total, the main objective of this review is to encourage further research in this poorly explored field of environmental molecular toxicology.

mTOR signalling and cellular metabolism are mutual determinants in cancer

Oncogenic signalling and metabolic alterations are interrelated in cancer cells. mTOR, which is frequently activated in cancer, controls cell growth and metabolism. mTOR signalling regulates amino acid, glucose, nucleotide, fatty acid and lipid metabolism. Conversely, metabolic inputs, such as amino acids, activate mTOR. In this Review, we discuss how mTOR signalling rewires cancer cell metabolism and delineate how changes in metabolism, in turn, sustain mTOR signalling and tumorigenicity. Several drugs are being developed to perturb cancer cell metabolism. However, their efficacy as stand-alone therapies, similar to mTOR inhibitors, is limited. Here, we discuss how the interdependence of mTOR signalling and metabolism can be exploited for cancer therapy.

Proteomics analysis demonstrating rosmarinic acid suppresses cell growth by blocking the glycolytic pathway in human HepG2 cells

Rosmarinic acid (RA), isolated from herbal balm mint plants, has demonstrated potent anti-tumor properties against liver cancer. However, the precise underlying mechanisms remain unclear. This study aimed to investigate the molecular mechanisms of RA in HepG2 cells. RA anti-tumor activity was assessed using 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, and Hoechst 33258 staining. Apoptosis and the cell cycle distribution were evaluated by flow cytometry. A proteomics approach was used to identify differentially expressed proteins following RA treatment in HepG2 cells, and quantitative reverse transcription-quantitative polymerase chain reaction was used to validate the results. Bioinformatics analysis was also implemented to further understand the identified proteins, and western blotting was used to analyze the associated proteins. Our results suggested that RA treatment significantly inhibits the viability of HepG2 cells. The MTT and LDH assays indicated dose-dependent decreases in cell proliferation following RA treatment. Hoechst 33258 staining and flow cytometry analysis showed that RA exhibits an apoptosis-inducing effect and induces cell cycle arrest in G1. The proteomics analysis successfully identified 16 differentially expressed proteins. Bioinformatics analysis indicated that the identified proteins participated in several biological processes and exhibited various molecular functions, mainly related to inactivation of the glycolytic pathway. Further western blotting analysis showed that RA could downregulate the expression of glucose transporter-1 and hexokinase-2, leading to the suppression of glucose consumption and generation of lactate and ATP. Taken together, our study found that RA exhibits significant cytotoxic effects by inhibiting cell proliferation and inducing apoptosis and cell cycle arrest, possibly by blocking the glycolytic pathway in human HepG2 cells.

Iodine-125 interstitial brachytherapy reduces tumor growth via Warburg effect inhibition in non-small cell lung cancer A549 ×enografts

Iodine-125 interstitial brachytherapy (125I-IBT) is an alternative and effective treatment option for unresectable non-small cell lung cancer (NSCLC), and the Warburg effect is a determinant of tumor growth. The present study aimed to explore the influence of 125I-IBT on tumor growth and the Warburg effect, and the potential mechanisms underlying NSCLC progression. Mice with A549 cell xenografts were evenly divided into a control group without 125I-IBT, and three treatment groups receiving 125I-IBT with 20, 40 and 60 Gy. Tumor volume (TV), maximum standardized uptake value (SUVmax) determined by 18F-fluorodeoxyglucose (18F-FDG) micro-positron emission tomography/computed tomography and mean optical density (MOD) of mammalian target of rapamycin (mTOR), c-Myc, hypoxia inducible factor-1α (HIF-1α) and glucose transporter 1 (GLUT1) staining were compared among groups. Tumor inhibition rate (TIR), 18F-FDG uptake attenuation rate (FUAR) and expression suppression rate (ESR) were also calculated on day 14 and 28. The results demonstrated that the mean TV in the 60 and 40 Gy groups was smaller compared with the control TVs since days 14 and 16, respectively. The mean SUVmax value of the 60 Gy group at day 14, and all treatment group SUVmax values at day 28 were lower compared with the controls. In addition, the MOD of mTOR and GLUT1 was lower in the 60 Gy group, compared with the other groups, and c-Myc and HIF-1α values were lower in the 40 and 60 Gy groups, compared with the control and 20 Gy group (P<0.05). SUVmax positively correlated to TV (day 14, r=0.711; day 28, r=0.586) and the MOD of c-Myc and GLUT1 (r=0.621 and 0.546, respectively; P<0.01). Furthermore, dose dependent increases were observed for TIR, FUAR and ESR. In conclusion, 125I-IBT reduced tumor growth by inhibiting the Warburg effect, which may have resulted from downregulation of mTOR, c-Myc, HIF-1α and GLUT1 expression, particularly c-Myc and GLUT1, in NSCLC A549 ×enografts.

Effects of β-caryophyllene on arginine ADP-ribosyltransferase 1-mediated regulation of glycolysis in colorectal cancer under high-glucose conditions

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of the development of colorectal cancer (CRC). A previous study revealed that the levels of arginine-specific mono-ADP-ribosyltransferase 1 (ART1) in CRC tissues from patients with T2DM were higher than in non-diabetic patients. Hyperglycemia, which is a risk factor of cancer, is a common feature of T2DM; however, the effects of ART1 on glycolysis and energy metabolism in CRC cells under high-glucose conditions remains to be elucidated. β-caryophyllene (BCP) has been reported to exert anticancer and hypoglycemic effects. In the present study, CT26 cells were cultured under a high-glucose conditions and the expression levels of relevant factors were detected by western blotting. Cell Counting Kit-8 assay, flow cytometry, Hoechst 33258 staining, ATP assay and lactic acid assay were used to detect the proliferation, apoptosis and energy metabolism of CT26 cells. To observe the effects of ART1 and BCP on tumor growth in vivo, CT26 cell tumors were successfully transplanted into BALB/c mice with T2DM. The results demonstrated that overexpression of ART1 may increase glycolysis and energy metabolism in CT26 CRC cells under high glucose conditions by regulating the protein kinase B/mammalian target of rapamycin/c‑Myc signaling pathway and the expression of glycolytic enzymes. BCP inhibited the effects induced by ART1, which may be due to a BCP-induced reduction in the expression levels of ART1 via nuclear factor-κB. Therefore, ART1 may be considered a therapeutic target for the treatment of diabetic patients with CRC.

Angelica gigas Nakai and Decursin Downregulate Myc Expression to Promote Cell Death in B-cell Lymphoma

Angelica gigas Nakai (AGN) is an oriental traditional medicine to treat anemia, dysmenorrhea, and migraine. However, its anti-lymphoma effect is yet to be tested. Here, we demonstrated that AGN and its major component decursin target Myc to suppress lymphomagenesis in vitro and in vivo. AGN inhibited cell viability in multiple B lymphoma cells, while sparing normal splenocytes and bone marrow cells. Increased cleaved PARP level and caspase 3/7 activity and the repression of survival-promoting AKT/mTOR and MAPK pathways downstream of BCR, were responsible for the pro-apoptotic effects of AGN. We found that Myc, a prominent downstream target of these signaling pathways, contributes to AGN-induced cell death. Moreover, co-treatment with AGN and a Myc inhibitor, JQ1 or 10058-F4 yielded synergistic cytotoxic activities against cancer cells with markedly reduced Myc expression. AGN downregulated Myc expression and suppressed tumorigenesis in Eμ-myc transgenic mice. The proapoptotic activities of AGN were recapitulated by decursin, indicating that the anti-tumor effect of AGN was mainly caused by decursin. These findings suggest that AGN and decursin possess potent anti-lymphoma activity, and combination therapies with AGN/decursin and a Myc inhibitor to target Myc more efficiently could be a valuable avenue to explore in the treatment of B-cell lymphoma.

Biological and metabolic effects of IACS-010759, an OxPhos inhibitor, on chronic lymphocytic leukemia cells

Blood cells from patients with chronic lymphocytic leukemia (CLL) are replicationally quiescent but transcriptionally, translationally, and metabolically active. Recently, we demonstrated that oxidative phosphorylation (OxPhos) is a predominant pathway in CLL for energy production and is further augmented in the presence of the stromal microenvironment. Importantly, CLL cells from patients with poor prognostic markers showed increased OxPhos. From these data, we theorized that OxPhos can be targeted to treat CLL. IACS-010759, currently in clinical development, is a small-molecule, orally bioavailable OxPhos inhibitor that targets mitochondrial complex I. Treatment of primary CLL cells with IACS-010759 greatly inhibited OxPhos but caused only minor cell death at 24 and 48 h. In the presence of stroma, the drug successfully inhibited OxPhos and diminished intracellular ribonucleotide pools. However, glycolysis and glucose uptake were induced as compensatory mechanisms. To mitigate the upregulated glycolytic flux, we used 2-deoxy-D-glucose in combination with IACS-010759. This combination reduced both OxPhos and glycolysis and induced cell death. Consistent with these data, low-glucose culture conditions sensitized CLL cells to IACS-010759. Collectively, these data suggest that CLL cells adapt to use a different metabolic pathway when OxPhos is inhibited and that targeting both OxPhos and glycolysis pathways is necessary for biological effect.