The Warburg effect and its cancer therapeutic implications

Chaga mushroom extract suppresses oral cancer cell growth via inhibition of energy metabolism

Oral cancer stands as a prevalent maligancy worldwide; however, its therapeutic potential is limited by undesired effects and complications. As a medicinal edible fungus, Chaga mushroom (Inonotus obliquus) exhibits anticancer effects across diverse cancers. Yet, the precise mechanisms underlying its efficacy remain unclear. We explored the detailed mechanisms underlying the anticancer action of Chaga mushroom extract in oral cancer cells (HSC-4). Following treatment with Chaga mushroom extracts, we analyzed cell viability, proliferation capacity, glycolysis, mitochondrial respiration, and apoptosis. Our findings revealed that the extract reduced cell viability and proliferation of HSC-4 cells while arresting their cell cycle via suppression of STAT3 activity. Regarding energy metabolism, Chaga mushroom extract inhibited glycolysis and mitochondrial membrane potential in HSC-4 cells, thereby triggering autophagy-mediated apoptotic cell death through activation of the p38 MAPK and NF-κB signaling pathways. Our results indicate that Chaga mushroom extract impedes oral cancer cell progression, by inhibiting cell cycle and proliferation, suppressing cancer cell energy metabolism, and promoting autophagy-mediated apoptotic cell death. These findings suggest that this extract is a promising supplementary medicine for the treatment of patients with oral cancer.

Inhibition of glycolysis and SIRT1/GLUT1 signaling ameliorates the apoptotic effect of Leptosidin in prostate cancer cells

Since the silent information regulation 2 homolog-1 (sirtuin, SIRT1) and glucose transporter 1 (GLUT1) are known to modulate cancer cell metabolism and proliferation, the role of SIRT1/GLUT1 signaling was investigated in the apoptotic effect of Leptosidin from Coreopsis grandiflora in DU145 and PC3 human prostate cancer (PCa) cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle analysis, Western blotting, cBioportal correlation analysis, and co-immunoprecipitation were used in this work. Leptosidin showed cytotoxicity, augmented sub-G1 population, and abrogated the expression of pro-poly (ADP-ribose) polymerase (pro-PARP) and pro-cysteine aspartyl-specific protease (pro-caspase3) in DU145 and PC3 cells. Also, Leptosidin inhibited the expression of SIRT1, GLUT1, pyruvate kinase isozymes M2 (PKM2), Hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA) in DU145 and PC3 cells along with disrupted binding of SIRT1 and GLUT1. Consistently, Leptosidin curtailed lactate, glucose, and ATP in DU145 and PC3 cells. Furthermore, SIRT1 depletion enhanced the decrease of GLUT1, LDHA, and pro-Cas3 by Leptosidin in treated DU145 cells, while pyruvate suppressed the ability of Leptosidin in DU145 cells. These findings suggest that Leptosidin induces apoptosis via inhibition of glycolysis and SIRT1/GLUT1 signaling axis in PCa cells.

The mechanisms of action of metformin on head and neck cancer in the pre-clinical setting: a scoping review

This scoping review identifies the mechanistic pathways of metformin when used to treat head and neck cancer cells, in the pre-clinical setting. Understanding the underlying mechanisms will inform future experimental designs exploring metformin as a potential adjuvant for head and neck cancer. This scoping review was conducted according to the Joanna-Briggs Institute framework. A structured search identified 1288 studies, of which 52 studies fulfilled the eligibility screen. The studies are presented in themes addressing hallmarks of cancer. Most of the studies demonstrated encouraging anti-proliferative effects in vitro and reduced tumor weight and volume in animal models. However, a few studies have cautioned the use of metformin which supported cancer cell growth under certain conditions.

Natural Product-Based Glycolysis Inhibitors as a Therapeutic Strategy for Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide. Targeted therapy against the epidermal growth factor receptor (EGFR) is a promising treatment approach for NSCLC. However, resistance to EGFR tyrosine kinase inhibitors (TKIs) remains a major challenge in its clinical management. EGFR mutation elevates the expression of hypoxia-inducible factor-1 alpha to upregulate the production of glycolytic enzymes, increasing glycolysis and tumor resistance. The inhibition of glycolysis can be a potential strategy for overcoming EGFR-TKI resistance and enhancing the effectiveness of EGFR-TKIs. In this review, we specifically explored the effectiveness of pyruvate dehydrogenase kinase inhibitors and lactate dehydrogenase A inhibitors in combating EGFR-TKI resistance. The aim was to summarize the effects of these natural products in preclinical NSCLC models to provide a comprehensive understanding of the potential therapeutic effects. The study findings suggest that natural products can be promising inhibitors of glycolytic enzymes for the treatment of EGFR-TKI-resistant NSCLC. Further investigations through preclinical and clinical studies are required to validate the efficacy of natural product-based glycolytic inhibitors as innovative therapeutic modalities for NSCLC.

Natural compounds as lactate dehydrogenase inhibitors: potential therapeutics for lactate dehydrogenase inhibitors-related diseases

Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions encompass glycolysis, and its abnormal activity is associated with numerous diseases. Targeting LDH has emerged as a vital approach in drug discovery, leading to the identification of LDH inhibitors among natural compounds, such as polyphenols, alkaloids, and terpenoids. These compounds demonstrate therapeutic potential against LDH-related diseases, including anti-cancer effects. However, challenges concerning limited bioavailability, poor solubility, and potential toxicity must be addressed. Combining natural compounds with LDH inhibitors has led to promising outcomes in preclinical studies. This review highlights the promise of natural compounds as LDH inhibitors for treating cancer, cardiovascular, and neurodegenerative diseases.

Lactobacillus plantarum Metabolites Elicit Anticancer Effects by Inhibiting Autophagy-Related Responses

Lactobacillus plantarum (L. plantarum) is a probiotic that has emerged as novel therapeutic agents for managing various diseases, such as cancer, atopic dermatitis, inflammatory bowel disease, and infections. In this study, we investigated the potential mechanisms underlying the anticancer effect of the metabolites of L. plantarum. We cultured L. plantarum cells to obtain their metabolites, created several dilutions, and used these solutions to treat human colonic Caco-2 cells. Our results showed a 10% dilution of L. plantarum metabolites decreased cell viability and reduced the expression of autophagy-related proteins. Moreover, we found co-treatment with L. plantarum metabolites and chloroquine, a known autophagy inhibitor, had a synergistic effect on cytotoxicity and downregulation of autophagy-related protein expression. In conclusion, we showed the metabolites from the probiotic, L. plantarum, work synergistically with chloroquine in killing Caco-2 cells and downregulating the expression of autophagy-related proteins, suggesting the involvement of autophagy, rather than apoptosis, in their cytotoxic effect. Hence, this study provides new insights into new therapeutic methods via inhibiting autophagy.

Cisplatin conjugation with an exopolysaccharide extracted from Lactobacillus gasseri potentiates its efficacy and attenuates its toxicity

The development of newer cisplatin analogs is constantly being investigated owing to its low solubility, poor pharmacokinetics, and dose-related toxicity. In order to address the limitations of current cisplatin therapy, the present study was undertaken. Cisplatin conjugation with an exopolysaccharide extracted from Lactobacillus gasseri (LG-EPS) showed remarkably enhanced and selective anticancer activity by targeting tumor cells overexpressing glucose transporter 1 (GLUT1). The EPS-cisplatin complex exhibited a 600-fold increase in aqueous solubility with a better pharmacokinetic profile (longer half-life) in comparison to cisplatin. Cell viability assay and western blotting demonstrated a strong correlation between the cytotoxicity profile and GLUT1 expressions in different cell lines. The concentration of DNA-bound platinum was also found to be significantly higher in EPS-cisplatin-treated cells. Quercetin, a competitive inhibitor of GLUTs, was shown to prevent this selective uptake of EPS-cisplatin complex. Surprisingly, EPS-cisplatin complex showed an exceptionally safer profile (4 times the maximum tolerated dose of cisplatin) in the acute toxicity study and was also more efficacious against the xenograft mice model. The study suggests that this green glycoconjugation can be an effective and safer strategy to broaden the therapeutic potential of anti-cancer drugs in general and cisplatin in particular.

AHNAK Contributes to Hepatocellular Carcinoma Growth by Interacting with IGF-1R

Neuroblast differentiation-associated protein AHNAK, a large structural scaffold protein, remains mysterious in biological processes. AHNAK plays a suppressive or progressive role in different types of cancers. To investigate the role of the AHNAK in hepatocellular carcinoma (HCC), cell viability assays were performed to determine the cell proliferation of the stable AHNAK-knockdown HepG2 cell line; co-immunoprecipitation (Co-IP) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) were performed on HCC and matched paracancerous (MPC) tissues. The Metascape platform was used for enrichment analyses; the "ComplexHeatmap" package was applied for cluster analyses and visualization. Co-IP, Western botting and immunofluorescence double staining were performed to assess the interactions between AHNAK and insulin-like growth factor 1 receptor (IGF-1R). AHNAK silencing reduced the viability of HepG2 cells; the interactome in HCC and MPC tissues enriched 204 pathways and processes, which partially reflected the signature of HCC field cancerization. AHNAK could co-localize and interact with IGF-1R. These results suggested that the AHNAK complex contributes to HCC growth, potentially by interacting with IGF-1R.

Plasma metabolomics for the assessment of the progression of non-small cell lung cancer

Objectives

Non-small cell lung cancer (NSCLC) is a leading type of lung cancer with a high mortality rate worldwide. Although many procedures for the diagnosis and prognosis assessment of lung cancer exist, they are often laborious, expensive, and invasive. This study aimed to develop an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS)-based analysis method for the plasma biomarkers of NSCLC with the potential to indicate the stages and progression of this malignancy conveniently and reliably.

Methods

A total of 53 patients with NSCLC in early stages (I–III) and advanced stage (IV) were classified into the early and advanced groups based on the tumor node metastasis staging system. A comprehensive metabolomic analysis of plasma from patients with NSCLC was performed via UPLC–MS/MS. Principal component analysis and partial least squares–discriminant analysis were conducted for statistical analysis. Potential biomarkers were evaluated and screened through receiver operating characteristic analyses and correlation analysis. Main differential metabolic pathways were also identified by utilizing metaboanalyst.

Results

A total of 129 differential metabolites were detected in accordance with the criteria of VIP ≥ 1 and a P-value of ≤ 0.05. The receiver operating characteristic curves indicated that 11 of these metabolites have the potential to be promising markers of disease progression. Apparent correlated metabolites were also filtered out. Furthermore, the 11 most predominant metabolic pathways with alterations involved in NSCLC were identified.

Conclusion

Our study focused on the plasma metabolomic changes in patients with NSCLC. These changes may be used for the prediction of the stage and progression of NSCLC. Moreover, we discussed the metabolic pathways wherein the altered metabolites were mainly enriched.

Natural compounds targeting glycolysis as promising therapeutics for gastric cancer: A review

Gastric cancer, a common malignant disease, seriously endangers human health and life. The high mortality rate due to gastric cancer can be attributed to a lack of effective therapeutic drugs. Cancer cells utilize the glycolytic pathway to produce energy even under aerobic conditions, commonly referred to as the Warburg effect, which is a characteristic of gastric cancer. The identification of new targets based on the glycolytic pathway for the treatment of gastric cancer is a viable option, and accumulating evidence has shown that phytochemicals have extensive anti-glycolytic properties. We reviewed the effects and mechanisms of action of phytochemicals on aerobic glycolysis in gastric cancer cells. Phytochemicals can effectively inhibit aerobic glycolysis in gastric cancer cells, suppress cell proliferation and migration, and promote apoptosis, via the PI3K/Akt, c-Myc, p53, and other signaling pathways. These pathways affect the expressions of HIF-1α, HK2, LDH, and other glycolysis-related proteins. This review further assesses the potential of using plant-derived compounds for the treatment of gastric cancer and sheds insight into the development of new drugs.

Whole-genome CRISPR screening identifies N-glycosylation as a genetic and therapeutic vulnerability in CALR-mutant MPNs

Calreticulin (CALR) mutations are frequent, disease-initiating events in myeloproliferative neoplasms (MPNs). Although the biological mechanism by which CALR mutations cause MPNs has been elucidated, there currently are no clonally selective therapies for CALR-mutant MPNs. To identify unique genetic dependencies in CALR-mutant MPNs, we performed a whole-genome clustered regularly interspaced short palindromic repeats (CRISPR) knockout depletion screen in mutant CALR-transformed hematopoietic cells. We found that genes in the N-glycosylation pathway (among others) were differentially depleted in mutant CALR-transformed cells as compared with control cells. Using a focused pharmacological in vitro screen targeting unique vulnerabilities uncovered in the CRISPR screen, we found that chemical inhibition of N-glycosylation impaired the growth of mutant CALR-transformed cells, through a reduction in MPL cell surface expression. We treated Calr-mutant knockin mice with the N-glycosylation inhibitor 2-deoxy-glucose (2-DG) and found a preferential sensitivity of Calr-mutant cells to 2-DG as compared with wild-type cells and normalization of key MPNs disease features. To validate our findings in primary human cells, we performed megakaryocyte colony-forming unit (CFU-MK) assays. We found that N-glycosylation inhibition significantly reduced CFU-MK formation in patient-derived CALR-mutant bone marrow as compared with bone marrow derived from healthy donors. In aggregate, our findings advance the development of clonally selective treatments for CALR-mutant MPNs.

Glycosylated phospholipid-coated upconversion nanoparticles for bioimaging of non-muscle invasive bladder cancers

Detection of non-muscle invasive bladder cancer (NMIBC) is crucial to facilitate complete tumor resection, thus improving the survival rate as well as reducing the recurrence frequency and treatment expense. Fluorescence imaging cystoscopy is an effective method for the detection of NMIBC. However, its application is limited as the commonly applied fluorescent agents such as dyes and photosensitizers usually lack specific tumor accumulation and are vulnerable to photobleaching. Furthermore, the broad emission band of conventional fluorescent agents limits their imaging and detection efficacy. To overcome these limitations, upconversion nanoparticles (UCNPs) have been selected as the fluorescent agent, due to their resistance to photobleaching, less background auto-fluorescence, and narrow emission bands. In order to achieve active tumor targeting, the UCNPs are coated with a glycosylated phospholipid layer. The glycosylated phospholipid-coated UCNPs exhibited high selective accumulation in cancer cells over normal cells and enhanced the upconversion luminescence (UCL) (at 540 nm and 660 nm) from bladder cancer cells under 980 nm laser irradiation. Glycosylated phospholipid coating that promotes uptake of UCNPs by cancer cells, and UCL emitted from UCNPs under NIR (980 nm) laser irradiation for cancer cell imaging.

Formation of Water-Soluble Complexes from Fullerene with Biocompatible Block Copolymers Bearing Pendant Glucose and Phosphorylcholine

Double-hydrophilic diblock copolymers, PMPC₁₀₀-block-PGEMA_n (M₁₀₀G_n), were synthesized via reversible addition-fragmentation chain transfer radical polymerization using glycosyloxyethyl methacrylate and 2-(methacryloyloxy)ethyl phosphorylcholine. The degree of polymerization (DP) of the poly(2-(methacryloyloxy) ethylphosphorylcholine) (PMPC) block was 100, whereas the DPs (n) of the poly(glycosyloxyethyl methacrylate) PGEMA block were 18, 48, and 90. Water-soluble complexes of C₇₀/M₁₀₀G_n and fullerene (C₇₀) were prepared by grinding M₁₀₀G_n and C₇₀ powders in a mortar and adding phosphate-buffered saline (PBS) solution. PMPC can form a water-soluble complex with hydrophobic C₇₀ using the same method. Therefore, the C₇₀/M₁₀₀G_n complexes have a core-shell micelle-like particle structure possessing a C₇₀/PMPC core and PGEMA shells. The maximum amounts of solubilization of C₇₀ in PBS solutions using 2 g/L each of M₁₀₀G₁₈, M₁₀₀G₄₈, and M₁₀₀G₉₀ were 0.518, 0.358, and 0.257 g/L, respectively. The hydrodynamic radius (R_h) of C₇₀/M₁₀₀G_n in PBS solutions was 55-75 nm. Spherical aggregates with a similar size to the R_h were observed by transmission electron microscopy. When the C₇₀/M₁₀₀G_n PBS solutions were irradiated with visible light, singlet oxygen was generated from C₇₀ in the core. It is expected that the C₇₀/M₁₀₀G_n complexes can be applied to photosensitizers for photodynamic therapy treatments.

PI3K-AKT Pathway Modulation by Thymoquinone Limits Tumor Growth and Glycolytic Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of death in men and the fourth in women worldwide and is characterized by deranged cellular energetics. Thymoquinone, an active component from Nigella sativa, has been extensively studied against cancer, however, its role in affecting deregulated cancer metabolism is largely unknown. Further, the phosphoinositide 3-kinase (PI3K) pathway is one of the most activated pathways in cancer and its activation is central to most deregulated metabolic pathways for supporting the anabolic needs of growing cancer cells. Herein, we provide evidence that thymoquinone inhibits glycolytic metabolism (Warburg effect) in colorectal cancer cell lines. Further, we show that such an abrogation of deranged cell metabolism was due, at least in part, to the inhibition of the rate-limiting glycolytic enzyme, Hexokinase 2 (HK2), via modulating the PI3/AKT axis. While overexpression of HK2 showed that it is essential for fueling glycolytic metabolism as well as sustaining tumorigenicity, its pharmacologic and/or genetic inhibition led to a reduction in the observed effects. The results decipher HK2 mediated inhibitory effects of thymoquinone in modulating its glycolytic metabolism and antitumor effects. In conclusion, we provide evidence of metabolic perturbation by thymoquinone in CRC cells, highlighting its potential to be used/repurposed as an antimetabolite drug, though the latter needs further validation utilizing other suitable cell and/or preclinical animal models.

Serum Metabolic Disturbances in Lung Cancer Investigated through an Elaborative NMR-Based Serum Metabolomics Approach

Detection of metabolic disturbances in lung cancer (LC) has the potential to aid early diagnosis/prognosis and hence improve disease management strategies through reliable grading, staging, and determination of neoadjuvant status in LC. However, a majority of previous metabolomics studies compare the normalized spectral features which not only provide ambiguous information but further limit the clinical translation of this information. Various such issues can be resolved by performing the concentration profiling of various metabolites with respect to formate as an internal reference using commercial software Chenomx. Continuing our efforts in this direction, the serum metabolic profiles were measured on 39 LC patients and 42 normal controls (NCs, comparable in age/sex) using high-field 800 MHz NMR spectroscopy and compared using multivariate statistical analysis tools to identify metabolic disturbances and metabolites of diagnostic potential. Partial least-squares discriminant analysis (PLS-DA) model revealed a distinct separation between LC and NC groups and resulted in excellent discriminatory ability with the area under the receiver-operating characteristic (AUROC) = 0.97 [95% CI = 0.89-1.00]. The metabolic features contributing to the differentiation of LC from NC samples were identified first using variable importance in projection (VIP) score analysis and then checked for their statistical significance (with p-value < 0.05) and diagnostic potential using the ROC curve analysis. The analysis revealed relevant metabolic disturbances associated with LC. Among various circulatory metabolites, six metabolites, including histidine, glutamine, glycine, threonine, alanine, and valine, were found to be of apposite diagnostic potential for clinical implications. These metabolic alterations indicated altered glucose metabolism, aberrant fatty acid synthesis, and augmented utilization of various amino acids including active glutaminolysis in LC.

A mathematical model for imaging and killing cancer cells by using concepts of the Warburg effect in designing a Graphene system

According to the Warburg effect, there are some significant differences between metabolisms, products and process of respirations of cancer cells and normal cells. For example, normal cells absorb oxygen and glucose and give water molecules, carbon dioxide, ATP molecules and some number of spinors; while cancer cells take glucose and give lactate, less number of ATP molecules and different number of spinors. Using this property, we can design a system from two graphene sheets that are connected by pairing the fourth free electrons of carbons. Then, we can break some pairs and produce some holes. The number of these holes should be equal to the number of radiated spinors by normal cells. Near a normal cell, all holes are filled and the graphene system doesn't emit any electrical current or wave. However, near a cancer cell, some extra holes or spinors remain that their motions produce some electrical currents. These currents force on cancer cell membranes and destroy them and consequently, cause the cell death. Also, these currents emit some electromagnetic waves which detectors could take them out of the human's body and consequently, they could play the main role in imaging.

Identification of Rare Cell Populations in Autofluorescence Lifetime Image Data

Drug‐resistant cells and anti‐inflammatory immune cells within tumor masses contribute to tumor aggression, invasion, and worse patient outcomes. These cells can be a small proportion (<10%) of the total cell population of the tumor. Due to their small quantity, the identification of rare cells is challenging with traditional assays. Single cell analysis of autofluorescence images provides a live‐cell assay to quantify cellular heterogeneity. Fluorescence intensities and lifetimes of the metabolic coenzymes reduced nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide allow quantification of cellular metabolism and provide features for classification of cells with different metabolic phenotypes. In this study, Gaussian distribution modeling and machine learning classification algorithms are used for the identification of rare cells within simulated autofluorescence lifetime image data of a large tumor comprised of tumor cells and T cells. A Random Forest machine learning algorithm achieved an overall accuracy of 95% for the identification of cell type from the simulated optical metabolic imaging data of a heterogeneous tumor of 20,000 cells consisting of 70% drug responsive breast cancer cells, 5% drug resistant breast cancer cells, 20% quiescent T cells and 5% activated T cells. High resolution imaging methods combined with single‐cell quantitative analyses allows identification and quantification of rare populations of cells within heterogeneous cultures

Targeting glucose metabolism to develop anticancer treatments and therapeutic patents

INTRODUCTION

One of the most distinctive hallmarks of cancer cells is increased glucose consumption for aerobic glycolysis which is named the Warburg effect. In recent decades, extensive research has been carried out to exploit this famous phenomenon, trying to detect promising targetable vulnerabilities in altered metabolism to fight cancer. Targeting aberrant glucose metabolism can perturb cancer malignant proliferation and even induce programmed cell death.

AREAS COVERED

This review covered the recent patents which focused on targeting key glycolytic enzymes including hexokinase, pyruvate dehydrogenase kinases and lactate dehydrogenase for cancer treatment.

EXPERT OPINION

Compared with the conventional cancer treatment, specifically targeting the well-known Achilles heel Warburg effect has attracted considerable attention. Although there is still no single glycolytic agent for clinical cancer treatment, the combination of glycolytic inhibitor with conventional anticancer drug or the combined use of multiple glycolytic inhibitors are being investigated extensively in recent years, which could emerge as attractive anticancer strategies.

Targeting the Interplay between Cancer Metabolic Reprogramming and Cell Death Pathways as a Viable Therapeutic Path

In cancer cells, metabolic adaptations are often observed in terms of nutrient absorption, biosynthesis of macromolecules, and production of energy necessary to meet the needs of the tumor cell such as uncontrolled proliferation, dissemination, and acquisition of resistance to death processes induced by both unfavorable environmental conditions and therapeutic drugs. Many oncogenes and tumor suppressor genes have a significant effect on cellular metabolism, as there is a close relationship between the pathways activated by these genes and the various metabolic options. The metabolic adaptations observed in cancer cells not only promote their proliferation and invasion, but also their survival by inducing intrinsic and acquired resistance to various anticancer agents and to various forms of cell death, such as apoptosis, necroptosis, autophagy, and ferroptosis. In this review we analyze the main metabolic differences between cancer and non-cancer cells and how these can affect the various cell death pathways, effectively determining the susceptibility of cancer cells to therapy-induced death. Targeting the metabolic peculiarities of cancer could represent in the near future an innovative therapeutic strategy for the treatment of those tumors whose metabolic characteristics are known.

The Key Role of the WNT/β-Catenin Pathway in Metabolic Reprogramming in Cancers under Normoxic Conditions

Simple Summary

The canonical WNT/β-catenin pathway is upregulated in cancers and plays a major role in proliferation, invasion, apoptosis and angiogenesis. Recent studies have shown that cancer processes are involved under normoxic conditions. These findings completely change the way of approaching the study of the cancer process. In this review, we focus on the fact that, under normoxic conditions, the overstimulation of the WNT/β-catenin pathway leads to modifications in the tumor micro-environment and the activation of the Warburg effect, i.e., aerobic glycolysis, autophagy and glutaminolysis, which in turn participate in tumor growth.

Abstract

The canonical WNT/β-catenin pathway is upregulated in cancers and plays a major role in proliferation, invasion, apoptosis and angiogenesis. Nuclear β-catenin accumulation is associated with cancer. Hypoxic mechanisms lead to the activation of the hypoxia-inducible factor (HIF)-1α, promoting glycolytic and energetic metabolism and angiogenesis. However, HIF-1α is degraded by the HIF prolyl hydroxylase under normoxia, conditions under which the WNT/β-catenin pathway can activate HIF-1α. This review is therefore focused on the interaction between the upregulated WNT/β-catenin pathway and the metabolic processes underlying cancer mechanisms under normoxic conditions. The WNT pathway stimulates the PI3K/Akt pathway, the STAT3 pathway and the transduction of WNT/β-catenin target genes (such as c-Myc) to activate HIF-1α activity in a hypoxia-independent manner. In cancers, stimulation of the WNT/β-catenin pathway induces many glycolytic enzymes, which in turn induce metabolic reprogramming, known as the Warburg effect or aerobic glycolysis, leading to lactate overproduction. The activation of the Wnt/β-catenin pathway induces gene transactivation via WNT target genes, c-Myc and cyclin D1, or via HIF-1α. This in turn encodes aerobic glycolysis enzymes, including glucose transporter, hexokinase 2, pyruvate kinase M2, pyruvate dehydrogenase kinase 1 and lactate dehydrogenase-A, leading to lactate production. The increase in lactate production is associated with modifications to the tumor microenvironment and tumor growth under normoxic conditions. Moreover, increased lactate production is associated with overexpression of VEGF, a key inducer of angiogenesis. Thus, under normoxic conditions, overstimulation of the WNT/β-catenin pathway leads to modifications of the tumor microenvironment and activation of the Warburg effect, autophagy and glutaminolysis, which in turn participate in tumor growth.

3-Bromopyruvate-induced glycolysis inhibition impacts larval growth and development and carbohydrate homeostasis in fall webworm, Hyphantria cunea Drury

As a typical glycolytic inhibitor, 3-bromopyruvate (3-BrPA) has been extensively studied in cancer therapy in recent decades. However, few studies focused on 3-BrPA in regulating the growth and development of insects, and the relationship and regulatory mechanism between glycolysis and chitin biosynthesis remain largely unknown. The Hyphantria cunea, named fall webworm, is a notorious defoliator, which caused a huge economic loss to agriculture and forestry. Here, we investigated the effects of 3-BrPA on the growth and development, glycolysis, carbohydrate homeostasis, as well as chitin synthesis in H. cunea larvae. To elucidate the action mechanism of 3-BrPA on H. cunea will provide a new insight for the control of this pest. The results showed that 3-BrPA dramatically restrained the growth and development of H. cunea larvae and resulted in larval lethality. Meanwhile, we confirmed that 3-BrPA caused a significant decrease in carbohydrate, adenosine triphosphate (ATP), pyruvic acid (PA), and triglyceride (TG) levels by inhibiting glycolysis in H. cunea larvae. Further studies indicated that 3-BrPA significantly affected the activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and trehalase, as well as expressions of the genes related to glycolysis, resulting in carbohydrate homeostasis disorder. Moreover, it was found that 3-BrPA enhanced 20-hydroxyecdysone (20E) signaling by upregulating HcCYP306A1 and HcCYP314A1, two critical genes in 20E synthesis pathway, and accelerated chitin synthesis by upregulating transcriptional levels of genes in the chitin synthesis pathway in H. cunea larvae. Taken together, our findings provide a novel insight into the mechanism of glycolytic inhibitor in regulating the growth and development of insects, and lay a foundation for the potential application of glycolytic inhibitors in pest control as well.

Role of Mitochondria in Radiation Responses: Epigenetic, Metabolic, and Signaling Impacts

Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.

Clinical Implications of Malnutrition in the Management of Patients with Pancreatic Cancer: Introducing the Concept of the Nutritional Oncology Board

Pancreatic cancer represents a very challenging disease, with an increasing incidence and an extremely poor prognosis. Peculiar features of this tumor entity are represented by pancreatic exocrine insufficiency and an early and intense nutritional imbalance, leading to the highly prevalent and multifactorial syndrome known as cancer cachexia. Recently, also the concept of sarcopenic obesity has emerged, making the concept of pancreatic cancer malnutrition even more multifaceted and complex. Overall, these nutritional derangements play a pivotal role in contributing to the dismal course of this malignancy. However, their relevance is often underrated and their assessment is rarely applied in clinical daily practice with relevant negative impact for patients' outcome in neoadjuvant, surgical, and metastatic settings. The proper detection and management of pancreatic cancer-related malnutrition syndromes are of primary importance and deserve a specific and multidisciplinary (clinical nutrition, oncology, etc.) approach to improve survival, but also the quality of life. In this context, the introduction of a "Nutritional Oncology Board" in routine daily practice, aimed at assessing an early systematic screening of patients and at implementing nutritional support from the time of disease diagnosis onward seems to be the right path to take.

LncRNA OIP5-AS1 Regulates the Warburg Effect Through miR-124-5p/IDH2/HIF-1α Pathway in Cervical Cancer

Hypoxia reprogrammed glucose metabolism affects the Warburg effect of tumor cells, but the mechanism is still unclear. Long-chain non-coding RNA (lncRNA) has been found by many studies to be involved in the Warburg effect of tumor cells under hypoxic condition. Herein, we find that lncRNA OIP5-AS1 is up-regulated in cervical cancer tissues and predicts poor 5-years overall survival in cervical cancer patients, and it promotes cell proliferation of cervical cancer cells in vitro and in vivo. Moreover, OIP5-AS1 is a hypoxia-responsive lncRNA and is essential for hypoxia-enhanced glycolysis which is IDH2 or hypoxia inducible factor-1α (HIF-1α) dependent. In cervical cancer cells, OIP5-AS1 promotes IDH2 expression by inhibiting miR-124-5p, and IDH2 promotes the Warburg effect of cervical under hypoxic condition through regulating HIF-1α expression. In conclusion, hypoxia induced OIP5-AS1 promotes the Warburg effect through miR-124-5p/IDH2/HIF-1α pathway in cervical cancer.

Molecular docking analysis of pyruvate kinase M2 with a potential inhibitor from the ZINC database

The pyruvate kinase M2 isoform (PKM2) is linked with cancer. Therefore, it is of interest to document the molecular docking analysis of Pyruvate Kinase M2 (PDB ID: 4G1N) with potential activators from the ZINC database. Thus, we document the optimal molecular docking features of a compound having ID ZINC000034285235 with PKM2 for further consideration.

Gas generating microspheres for immediate release of Hsp90 inhibitor aiming at postembolization hypoxia in transarterial chemoembolization therapy of hepatocellular carcinoma

CO₂ gas generating poly(lactic-co-glycolic acid) (PLGA) microsphere (MS) was designed for rapid release of tanespimycin (17-AAG) in transarterial chemoembolization (TACE) treatment of hepatocellular carcinoma (HCC). As poorly water-soluble drug is generally released from PLGA MS in a sustained manner, the drug release profile should be controlled according to its clinical indications. In current study, responding to immediate increase in hypoxia inducible factor-1α (HIF-1α) level under hypoxia state followed by embolization of tumor feeding arteries, sodium bicarbonate (NaHCO₃) was added to PLGA/17-AAG MS for fast drug release by CO₂ gas generation in slightly acidic tumor microenvironment. With the aid of NaHCO₃, initial burst release of 17-AAG was available without losing the micron-size and spherical shape of designed MS for embolization of artery. Acid-responsive CO₂ gas generation and subsequent immediate release of 17-AAG from MS were successfully verified. PLGA/17-AAG/NaHCO₃ MS-treated group exhibited higher antiproliferation and apoptosis induction efficacies in McA-RH7777 and SNU-761 cells. McA-RH7777 tumor-implanted rats treated by TACE using PLGA/17-AAG/NaHCO₃ MS presented a complete therapeutic response. All these findings suggest that developed tumor microenvironment-responsive gas-generating MS can be efficiently applied to TACE therapy of HCC.

Inhibition of ribosomal RNA processing 15 Homolog (RRP15), which is overexpressed in hepatocellular carcinoma, suppresses tumour growth via induction of senescence and apoptosis

Recent studies suggest that RRP15 (Ribosomal RNA Processing 15 Homolog) might be a potential target for cancer therapy. However, the role of RRP15 in hepatocarcinogenesis remains poorly delineated. In this study, we aimed to evaluate the expression and biological function of RRP15 in human hepatocellular carcinoma (HCC). We show that RRP15 was up regulated in HCC cell lines and tumours. Up-regulation of RRP15 in HCC tumours was also correlated with unfavorable prognosis. We further show that the frequent up-regulation of RRP15 in HCCs is at least partly driven by recurrent gene copy gain at chromosome 1q41. Functional studies indicated that RRP15 knockdown suppresses HCC proliferation and growth both in vitro and in vivo. Mechanistically, RRP15 depletion in p53-wild-type HepG2 cells induced senescence via activation of the p53-p21 signalling pathway through enhanced interaction of RPL11 with MDM2, as well as inhibition of SIRT1-mediated p53 deacetylation. Moreover, RRP15 depletion in p53-mutant PLC5 and p53-deleted Hep3B cells induced metabolic shift from the glycolytic pentose-phosphate to mitochondrial oxidative phosphorylation via regulating a series of key genes such as HK2 and TIGAR, and thus, promoted the generation of ROS and apoptosis. Taken together, our findings provide evidence for an important role of the RRP15 gene in hepatocarcinogenesis through regulation of HCC proliferation and growth, raising the possibility that targeting RRP15 may represent a potential therapeutic strategy for HCC treatment.

Taurine Upregulates miRNA-122-5p Expression and Suppresses the Metabolizing Enzymes of Glycolytic Pathway in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a complicated disease with a poor prognosis and high mortality rates. The prevention, control, diagnosis, and treatment of liver cancer have become vital focuses in healthcare research.

AIM

This study aimed to evaluate the in vitro effect of taurine (Tau) on the expression of miR-122-5p that targets some limiting glycolytic enzymes and affects the overall glycolytic pathway in HepG2 cells.

METHOD

IC₅₀ and the inhibitory effect of Tau on cell proliferation were measured after 48 h by MTT assay. Then, the mRNA expressions of some apoptosis-related genes P53, BAX, Caspase-3, and Bcl-2 were measured using quantitative real-time (qRT-PCR) and the protein levels were confirmed by enzyme-linked immunosorbent assay (ELISA). The activities of some antioxidant's biomarkers were assessed. The gene expression of miR-122-5p that targets some limiting glycolytic enzymes; Aldolase and Lactate dehydrogenase (LDH), were evaluated after treatment with Tau for 48 h.

RESULTS

A Significant inhibition in the proliferation of HepG2 was encountered after treatment with Tau in a dose-dependent manner. Moreover, the expression of apoptotic genes p53, Bax, and Caspase-3 exhibited a significant upregulation, while Bcl-2 showed a significant downregulation. These alterations in the expression levels were also confirmed on the protein level. The antioxidant activities of GPx, CAT, and NO were significantly elevated versus untreated control. Also, a significant increase in the expression level of miR-122-5p was observed after treatment with Tau affecting the metabolic activity of HCC cells. Concomitantly, a significant inhibition in ALDOA protein and the hallmark of glycolytic enzymes LDH and Aldolase were observed.

CONCLUSIONS

These observations showed that taurine inhibits HepG2 cell proliferation and restores the expression of miR-122-5p which inhibits the hallmark glycolytic enzymes and ultimately the metabolic activity of HCC cells. Tau is assumed to be a promising and effective antitumor therapy of HCC.

Increased Expression of PDK4 Was Displayed in Gastric Cancer and Exhibited an Association With Glucose Metabolism

Previous studies reported that pyruvate dehydrogenase kinase 4 (PDK4) is closely related to diabetes, heart disease, and carcinomas. Nevertheless, the role of PDK4 in gastric cancer (GC) occurrence and development is yet poorly understood. Our experiments were taken to evaluate PDK4's function in GC. The Cancer Genome Atlas tumor genome map database was employed to validate the levels of PDK family in different grades and stages of GC. The survival ratio of PDK families in GC was detected by the Kaplan-Meier plotter database. The links existing in the expression of PDK family and the level of tumor-infiltrating immune cells were investigated by tumor immunity assessment resource (TIMER). PDK4-associated signal pathways in GC were analyzed by the Kyoto Encyclopedia of Genes and Genomes pathway analysis. PDK4 mRNA level in the GC cells was measured by qRT-PCR. Cell counting kit-8 and Transwell assays were separately carried out to evaluate PDK4-induced influence on GC cell proliferation, migration, and invasion. Our data suggested that GC cells highly expressed PDK4, and PDK4 expression presented a significant relation with the staging, grade, and survival rate of GC. PDK4 expression presented a positive correlation with the types of different infiltrating immune cells, comprising B cells, CD4+ T cells, and dendritic cells. Meanwhile, PDK4 expression exhibited a strong association with macrophages. Survival analysis revealed that the expression of PDK4 displayed a relationship with the prognosis of patients. Therefore, PDK4 was liable to be a biomarker for prognosis. Our results further displayed that PDK4 might modulate the glycolysis level in GC cells, and its expression was associated with GC cell proliferation, migration, and invasion. These data may provide insights into designing a new treatment strategy for GC.

Radiation Resistance: A Matter of Transcription Factors

Currently, radiation therapy is one of the standard therapies for cancer treatment. Since the first applications, the field of radiotherapy has constantly improved, both in imaging technologies and from a dose-painting point of view. Despite this, the mechanisms of resistance are still a great problem to overcome. Therefore, a more detailed understanding of these molecular mechanisms will allow researchers to develop new therapeutic strategies to eradicate cancer effectively. This review focuses on different transcription factors activated in response to radiotherapy and, unfortunately, involved in cancer cells’ survival. In particular, ionizing radiations trigger the activation of the immune modulators STAT3 and NF-κB, which contribute to the development of radiation resistance through the up-regulation of anti-apoptotic genes, the promotion of proliferation, the alteration of the cell cycle, and the induction of genes responsible for the Epithelial to Mesenchymal Transition (EMT). Moreover, the ROS-dependent damaging effects of radiation therapy are hampered by the induction of antioxidant enzymes by NF-κB, NRF2, and HIF-1. This protective process results in a reduced effectiveness of the treatment, whose mechanism of action relies mainly on the generation of free oxygen radicals. Furthermore, the previously mentioned transcription factors are also involved in the maintenance of stemness in Cancer Stem Cells (CSCs), a subset of tumor cells that are intrinsically resistant to anti-cancer therapies. Therefore, combining standard treatments with new therapeutic strategies targeted against these transcription factors may be a promising opportunity to avoid resistance and thus tumor relapse.

Autophagy and glycolysis independently attenuate silibinin-induced apoptosis in human hepatocarcinoma HepG2 and Hep3B cells

PURPOSE

The mechanism of cytotoxicity of silibinin on two human hepatocellular carcinoma (HCC) cell lines, HepG2 (p53 wild-type) and Hep3B cells (p53 null), is examined in relation with the induction of autophagy and phosphorylation of AMP-activated protein kinase (p-AMPK).

MATERIALS AND METHODS

Levels of apoptosis in relation to the levels of autophagy and those of glycolysis-related proteins, glucose transporter 1/4 (Glut1/4) and hexokinase-II (HK2), in HepG2 and Hep3B cells were examined.

RESULTS

Silibinin-induced apoptosis was incomplete for HCC cell death in that up-regulated autophagy and/or reduced level of glycolysis, which are induced by silibinin treatment, antagonized silibinin-induced apoptosis. Inhibition of autophagy with 3-methyl adenine (3MA) or blocking of AMP-activated protein kinase (AMPK) activation with Compound C (CC) enhanced silibinin-induced apoptosis. The results confirm that AMPK involved in autophagy as well as in glycolysis remaining with silibinin is responsible for attenuation of silibinin-induced apoptosis. Blocking of AMPK or autophagy contributes to the enhancement of silibinin's cytotoxicity to HepG2 and Hep3B cells.

CONCLUSION

This study shows that incomplete apoptosis of HCC by silibinin treatment becomes complete by repression of autophagy and/or glycolysis.

Knockdown of ZNF479 inhibits proliferation and glycolysis of gastric cancer cells through regulating β-catenin/c-Myc signaling pathway

Gastric cancer is the fifth most common malignancy and the third most deadly tumor in the world. Zinc finger protein 479 (ZNF479) has been demonstrated to play crucial roles in hepatocellular carcinoma. However, the function of ZNF479 in gastric cancer remains to be clarified. The current study aimed to investigate the role of ZNF479 in gastric cancer progression and elucidate the potential molecular mechanism. In this study, Cell Count Kit-8 and colony formation assays demonstrated that knockdown of ZNF479 inhibited cell proliferation in AGS and SGC-7901 cells. Of note, knockdown of ZNF479 hinders tumor growth of xenograft tumor mice. What is more, knockdown of ZNF479 inhibited glucose uptake, lactate production, adenosine triphosphate level, and extracellular acidification ratio; increased oxygen consumption ratio in gastric cancer cells; and decreased the expression of glycolytic proteins both in vitro and in vivo. Furthermore, analysis mechanism suggests that ZNF479 participated in the regulation of gastric cancer progression through affecting the β-catenin/c-Myc signaling pathway. Collectively, ZNF479 plays a role as an oncogene through modulating β-catenin/c-Myc signaling pathway in the development of gastric cancer, which provides a new research target for future studies.

Unraveling the origin of glucose mediated disparate proliferation dynamics of cancer stem cells

Cancer stem cells (CSCs) often switch on their self-renewal programming aggressively to cause a relapse of cancer. Intriguingly, glucose triggers the proliferation propensities in CSCs by controlling the expression of the key transcription factor-like Nanog. However, the factors that critically govern this glucose-stimulated proliferation dynamics of CSCs remain elusive. Herein, by proposing a mathematical model of glucose-mediated Nanog regulation, we showed that the differential proliferation behavior of CSCs and cell-type similar to CSCs can be explained by considering the experimentally observed varied expression levels of key positive (STAT3) and negative (p53) regulators of Nanog. Our model reconciles various experimental observations and predicts ways to fine-tune the proliferation dynamics of these cell types in a context-dependent manner. In future, these modeling insights will be useful in developing improved therapeutic strategies to get rid of harmful CSCs.

MicroRNAs as Modulators of Tumor Metabolism, Microenvironment, and Immune Response in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality. Molecular heterogeneity and absence of biomarkers helping patient allocation to the best therapeutic option contribute to poor prognosis in advanced stages. MicroRNAs’ (miRNAs) deregulated expression contributes to tumor development and progression and influences drug resistance in HCC. Accordingly, miRNAs have been extensively investigated as both biomarkers and therapeutic targets. The diagnostic and prognostic roles of circulating miRNAs have been ascertained, though with some inconsistencies across studies. From a therapeutic perspective, miRNA-based approaches demonstrated safety profiles and antitumor efficacy in HCC animal models. Nevertheless, caution should be used when transferring preclinical findings to the clinic, due to possible molecular inconsistency between animal models and the heterogeneous patterns of human diseases. A wealth of information is offered by preclinical studies exploring the mechanisms driving miRNAs’ aberrant expression, the molecular cascades triggered by miRNAs and the corresponding phenotypic changes. Ex-vivo analyses confirmed these results, further shedding light on the intricacy of the human disease often overcoming pre-clinical models. This complexity seems to be ascribed to the intrinsic heterogeneity of HCC, to different risk factors driving its development, as well as to changes across stages and previous treatments. Preliminary findings suggest that miRNAs associated with specific risk factors might be more informative in defined patients’ subgroups. The first issue to be considered when trying to envisage a possible translational perspective is the molecular context that often drives different miRNA functions, as clearly evidenced by “dual” miRNAs. Concerning the possible roles of miRNAs as biomarkers and therapeutic targets, we will focus on miRNAs’ involvement in metabolic pathways and in the modulation of tumor microenvironment, to support their exploitation in defined contexts.

Metabolic and Amino Acid Alterations of the Tumor Microenvironment

Metabolic changes driven by the hostile tumor microenvironment surrounding cancer cells and the effect of these changes on tumorigenesis and metastatic potential have been known for a long time. The usual point of interest is glucose and changes in its utilization by cancer cells, mainly in the form of the Warburg effect. However, amino acids, both intra- and extracellular, also represent an important aspect of tumour microenvironment, which can have a significant effect on cancer cell metabolism and overall development of the tumor. Namely, alterations in the metabolism of amino acids glutamine, sarcosine, aspartate, methionine and cysteine have been previously connected to the tumor progression and aggressivity of cancer. The aim of this review is to pinpoint current gaps in our knowledge of the role of amino acids as a part of the tumor microenvironment and to show the effect of various amino acids on cancer cell metabolism and metastatic potential. This review shows limitations and exceptions from the traditionally accepted model of Warburg effect in some cancer tissues, with the emphasis on prostate cancer, because the traditional definition of Warburg effect as a metabolic switch to aerobic glycolysis does not always apply. Prostatic tissue both in a healthy and transformed state significantly differs in many metabolic aspects, including the metabolisms of glucose and amino acids, from the metabolism of other tissues. Findings from different tissues are, therefore, not always interchangeable and have to be taken into account during experimentation modifying the environment of tumor tissue by amino acid supplementation or depletion, which could potentially serve as a new therapeutic approach.

Dichloroacetate and PX-478 exhibit strong synergistic effects in a various number of cancer cell lines

Background

One key approach for anticancer therapy is drug combination. Drug combinations can help reduce doses and thereby decrease side effects. Furthermore, the likelihood of drug resistance is reduced. Distinct alterations in tumor metabolism have been described in past decades, but metabolism has yet to be targeted in clinical cancer therapy. Recently, we found evidence for synergism between dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor, and the HIF-1α inhibitor PX-478. In this study, we aimed to analyse this synergism in cell lines of different cancer types and to identify the underlying biochemical mechanisms.

Methods

The dose-dependent antiproliferative effects of the single drugs and their combination were assessed using SRB assays. FACS, Western blot and HPLC analyses were performed to investigate changes in reactive oxygen species levels, apoptosis and the cell cycle. Additionally, real-time metabolic analyses (Seahorse) were performed with DCA-treated MCF-7 cells.

Results

The combination of DCA and PX-478 produced synergistic effects in all eight cancer cell lines tested, including colorectal, lung, breast, cervical, liver and brain cancer. Reactive oxygen species generation and apoptosis played important roles in this synergism. Furthermore, cell proliferation was inhibited by the combination treatment.

Conclusions

Here, we found that these tumor metabolism-targeting compounds exhibited a potent synergism across all tested cancer cell lines. Thus, we highly recommend the combination of these two compounds for progression to in vivo translational and clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08186-9.

Abnormal saccharides affecting cancer multi-drug resistance (MDR) and the reversal strategies

Clinically, chemotherapy is the mainstay in the treatment of multiple cancers. However, highly adaptable and activated survival signaling pathways of cancer cells readily emerge after long exposure to chemotherapeutics drugs, resulting in multi-drug resistance (MDR) and treatment failure. Recently, growing evidences indicate that the molecular action mechanisms of cancer MDR are closely associated with abnormalities in saccharides. In this review, saccharides affecting cancer MDR development are elaborated and analyzed in terms of aberrant aerobic glycolysis and its related enzymes, abnormal glycan structures and their associated enzymes, and glycoproteins. The reversal strategies including depletion of ATP, circumventing the original MDR pathway, activation by or inhibition of sugar-related enzymes, combination therapy with traditional cytotoxic agents, and direct modification on the sugar moiety, are ultimately proposed. It follows that abnormal saccharides have a significant effect on cancer MDR development, providing a new perspective for overcoming MDR and improving the outcome of chemotherapy.

Pyruvate kinase M2 in chronic inflammations: a potpourri of crucial protein-protein interactions

Chronic inflammation (CI) is a primary contributing factor involved in multiple diseases like cancer, stroke, diabetes, Alzheimer's disease, allergy, asthma, autoimmune diseases, coeliac disease, glomerulonephritis, sepsis, hepatitis, inflammatory bowel disease, reperfusion injury, and transplant rejections. Despite several expansions in our understanding of inflammatory disorders and their mediators, it seems clear that numerous proteins participate in the onset of CI. One crucial protein pyruvate kinase M2 (PKM2) much studied in cancer is also found to be inextricably woven in the onset of several CI's. It has been found that PKM2 plays a significant role in several disorders using a network of proteins that interact in multiple ways. For instance, PKM2 forms a close association with epidermal growth factor receptors (EGFRs) for uncontrolled growth and proliferation of tumor cells. In neurodegeneration, PKM2 interacts with apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) to onset Alzheimer's disease pathogenesis. The cross-talk of protein tyrosine phosphatase 1B (PTP1B) and PKM2 acts as stepping stones for the commencement of diabetes. Perhaps PKM2 stores the potential to unlock the pathophysiology of several diseases. Here we provide an overview of the notoriously convoluted biology of CI's and PKM2. The cross-talk of PKM2 with several proteins involved in stroke, Alzheimer's, cancer, and other diseases has also been discussed. We believe that considering the importance of PKM2 in inflammation-related diseases, new options for treating various disorders with the development of more selective agents targeting PKM2 may appear.

Metabolomics of Gastric Cancer

Gastric cancer is the fourth most common malignancy worldwide and the third leading cause of cancer deaths. Recent metabolomics research has advanced our understanding of the relationship between metabolic reprogramming and gastric cancer progression and led to the discovery of metabolic targets for potential clinical applications and therapeutic interventions. As a powerful tool for metabolite and flux measurement, metabolomics not only allows a comprehensive analysis of metabolites and related metabolic pathways but also can investigate the interactions between gastric cancer cells and tumour microenvironment as well as between the cancer cells and gastric microbiome. In this chapter, we aim to summarize the recent advances in gastric cancer metabolism and discuss the applications of metabolomics for target discovery in gastric cancer.

Altered glycolysis results in drug-resistant in clinical tumor therapy

Cancer cells undergo metabolic reprogramming, including increased glucose metabolism, fatty acid synthesis and glutamine metabolic rates. These enhancements to three major metabolic pathways are closely associated with glycolysis, which is considered the central component of cancer cell metabolism. Increasing evidence suggests that dysfunctional glycolysis is commonly associated with drug resistance in cancer treatment, and aberrant glycolysis plays a significant role in drug-resistant cancer cells. Studies on the development of drugs targeting these abnormalities have led to improvements in the efficacy of tumor treatment. The present review discusses the changes in glycolysis targets that cause drug resistance in cancer cells, including hexokinase, pyruvate kinase, pyruvate dehydrogenase complex, glucose transporters, and lactate, as well the underlying molecular mechanisms and corresponding novel therapeutic strategies. In addition, the association between increased oxidative phosphorylation and drug resistance is introduced, which is caused by metabolic plasticity. Given that aberrant glycolysis has been identified as a common metabolic feature of drug-resistant tumor cells, targeting glycolysis may be a novel strategy to develop new drugs to benefit patients with drug-resistance.

Investigation into the role of anti-diabetic agents in cachexia associated with metastatic cancer

Cancer cachexia (CC) is a syndrome associated with cancer, and the global burden is increasing rapidly. Alteration in carbohydrate, lipid and protein metabolism along with systemic inflammation are characteristics of CC. Until now the available treatment for CC is limited to controlling inflammation and nutrition. Anti-diabetics are widely used agents to treat diabetics, this agent's act by regulating the carbohydrate metabolism, also they are known to have beneficial effects in maintaining protein and lipid balance. Role of anti-diabetics in cancer is being evaluated continuously and biguanides, dipeptidyl peptidase 4 (DPP4) inhibitors and Sodium glucose co-transporter 2 (SGLT2) inhibitors have proven anti-cancer potential. In this study, metastatic B16-F1 cell line induced cancer cachexia model used to evaluate potential of biguanides (metformin), DPP-4 inhibitors (teneligliptin and vildagliptin) and SGLT2 inhibitors (empagliflozin and dapagliflozin) in cancer cachexia. Our results suggest that anti-diabetic agents have potential to decrease rate of proliferation of tumor, restrict body mass markers, decrease inflammation, regulate carbohydrate mechanism and induce skeletal muscle hypertrophy. These findings may be helpful in management of cancer cachexia and increase the quality of life and survival chances of cancer cachexia patient.

In silico identification and in vitro activity of natural products as ADP-ribosyl transferase member 8 inhibitors

Aim: ADP-ribosyl transferase member 8 (ARTD8) of the ARTD superfamily has been identified as a possible anti-cancer, antiviral and anti-inflammatory target. Method: Pure actives from natural products with a documented anti-cancer activity were docked into the catalytic site of 3SMI.pdb using PyRx and AutoDock Vina. Results: Epigallocatechin gallate (EGCG), trans-resveratrol, indol-3-carbinol, curcumin, quercetin and naringenin were investigated, in vitro, against ARTD8, revealing EGCG and quercetin as lead compounds, with EGCG displaying complete inhibition at 10 μM. Both EGCG and quercetins docked poses spanned across both the nicotinamide and adenine subsites of the catalytic domain, interacting with conserved residues Ser1641 and/or Ser1607 and Tyr1646. Thereby, suggesting that the meta-hydroxy group on the catechin ring B backbone may be responsible for these inhibition effects.

Metabolic Reprogramming is a Hallmark of Metabolism Itself

The reprogramming of metabolism has been identified as one of the hallmarks of cancer. It is becoming more and more frequent to connect other diseases with metabolic reprogramming. This article aims to argue that metabolic reprogramming is not driven by disease but instead is the main hallmark of metabolism, based on its dynamic behavior that allows it to continuously adapt to changes in the internal and external conditions.

Synergisms of genome and metabolism stabilizing antitumor therapy (GMSAT) in human breast and colon cancer cell lines: a novel approach to screen for synergism

BACKGROUND

Despite an improvement of prognosis in breast and colon cancer, the outcome of the metastatic disease is still severe. Microevolution of cancer cells often leads to drug resistance and tumor-recurrence. To target the driving forces of the tumor microevolution, we focused on synergistic drug combinations of selected compounds. The aim is to prevent the tumor from evolving in order to stabilize disease remission. To identify synergisms in a high number of compounds, we propose here a three-step concept that is cost efficient, independent of high-throughput machines and reliable in its predictions.

METHODS

We created dose response curves using MTT- and SRB-assays with 14 different compounds in MCF-7, HT-29 and MDA-MB-231 cells. In order to efficiently screen for synergies, we developed a screening tool in which 14 drugs were combined (91 combinations) in MCF-7 and HT-29 using EC25 or less. The most promising combinations were verified by the method of Chou and Talalay.

RESULTS

All 14 compounds exhibit antitumor effects on each of the three cell lines. The screening tool resulted in 19 potential synergisms detected in HT-29 (20.9%) and 27 in MCF-7 (29.7%). Seven of the top combinations were further verified over the whole dose response curve, and for five combinations a significant synergy could be confirmed. The combination Nutlin-3 (inhibition of MDM2) and PX-478 (inhibition of HIF-1α) could be confirmed for all three cell lines. The same accounts for the combination of Dichloroacetate (PDH activation) and NHI-2 (LDH-A inhibition). Our screening method proved to be an efficient tool that is reliable in its projections.

CONCLUSIONS

The presented three-step concept proved to be cost- and time-efficient with respect to the resulting data. The newly found combinations show promising results in MCF-7, HT-29 and MDA-MB231 cancer cells.

Vitamin D receptor exhibits different pharmacodynamic features in tumoral and normal microenvironments: A molecular modeling study

The vitamin D receptor (VDR) constitutes a promising therapeutic target for the treatment of cancer. Unfortunately, its natural agonist calcitriol does not have clinical utility due to its potential to induce hypercalcemic effects at the concentrations required to display antitumoral activity. For this reason, the search for new calcitriol analogues with adequate therapeutic profiles has been actively pursued by the scientific community. We have previously reported the obtaining and the biological activity evaluation of new calcitriol analogues by modification of its sidechain, which exhibited relevant antiproliferative and selectivity profiles against tumoral and normal cells. In this work we conducted molecular modeling studies (i.e. molecular docking, molecular dynamics, constant pH molecular dynamics (CpHMD) and free energy of binding analysis) to elucidate at an atomistic level the molecular basis related to the potential of the new calcitriol analogues to achieve selectivity between tumoral and normal cells. Two histidine residues (His305 and His397) were found to exhibit a particular tautomeric configuration that produces the observed bioactivity. Also, different acid-based properties were observed for His305 and His307 with His305 showing an increased acidity (pKa 5.2) compared to His397 (pKa 6.8) and to the typical histidine residue. This behavior favored the pharmacodynamic interaction of the calcitriol analogues exhibiting selectivity for tumoral cells when VDR was modeled at the more acidic tumoral environment (pH ≅ 6) compared to the case when VDR was modeled at pH 7.4 (normal cell environment). On the other hand, non-selective compounds, including calcitriol, exhibited a similar interaction pattern with VDR when the receptor was modeled at both pH conditions. The results presented constitute the first evidence on the properties of the VDR receptor in different physicochemical environments and thus represent a significant contribution to the in silico screening and design of new calcitriol analogues.

Protein-Based Artificial Nanosystems in Cancer Therapy

Proteins, like actors, play different roles in specific applications. In the past decade, significant achievements have been made in protein-engineered biomedicine for cancer therapy. Certain proteins such as human serum albumin, working as carriers for drug/photosensitizer delivery, have entered clinical use due to their long half-life, biocompatibility, biodegradability, and inherent nonimmunogenicity. Proteins with catalytic abilities are promising as adjuvant agents for other therapeutic modalities or as anticancer drugs themselves. These catalytic proteins are usually defined as enzymes with high biological activity and substrate specificity. However, clinical applications of these kinds of proteins remain rare due to protease-induced denaturation and weak cellular permeability. Based on the characteristics of different proteins, tailor-made protein-based nanosystems could make up for their individual deficiencies. Therefore, elaborately designed protein-based nanosystems, where proteins serve as drug carriers, adjuvant agents, or therapeutic drugs to make full use of their intrinsic advantages in cancer therapy, are reviewed. Up-to-date progress on research in the field of protein-based nanomedicine is provided.

Pancreatic Cancer and Cachexia-Metabolic Mechanisms and Novel Insights

Cachexia is a major characteristic of multiple non-malignant diseases, advanced and metastatic cancers and it is highly prevalent in pancreatic cancer, affecting almost 70-80% of the patients. Cancer cachexia is a multifactorial condition accompanied by compromised appetite and changes in body composition, i.e., loss of fat. It is associated with lower effectiveness of treatment, compromised quality of life, and higher mortality. Understanding the complex pathways underlying the pathophysiology of cancer cachexia, new therapeutic targets will be unraveled. The interplay between tumor and host factors, such as cytokines, holds a central role in cachexia pathophysiology. Cytokines are possibly responsible for anorexia, hypermetabolism, muscle proteolysis, and apoptosis. In particular, cachexia in pancreatic cancer might be the result of the surgical removal of pancreas parts. In recent years, many studies have been carried out to identify an effective treatment algorithm for cachexia. Choosing the most appropriate treatment, the clinical effect and the risk of adverse effects should be taken under consideration. The purpose of this review is to highlight the pathophysiological mechanisms as well as the current ways of cachexia treatment in the pharmaceutical and the nutrition field.

Effect of pH on the structure and function of pyruvate dehydrogenase kinase 3: Combined spectroscopic and MD simulation studies

Pyruvate dehydrogenase kinase-3 (PDK3) plays important role in the glucose metabolism and is associated with cancer progression, and thus being considered as an attractive target for cancer therapy. In this study, we employed spectroscopic techniques to study the structural and conformational changes in the PDK3 at varying pH conditions ranging from pH 2.0 to 12.0. UV/Vis, fluorescence and circular dichroism spectroscopic measurements revealed that PDK3 maintains its native-like structure (both secondary and tertiary) in the alkaline conditions (pH 7.0-12.0). However, a significant loss in the structure was observed under acidic conditions (pH 2.0-6.0). The propensity of aggregate formation at pH 4.0 was estimated by thioflavin T fluorescence measurements. To further complement structural data, kinase activity assay was performed, and maximum activity of PDK3 was observed at pH 7.0-8.0 range; whereas, its activity was lost under acidic pH. To further see conformational changes at atomistic level we have performed all-atom molecular dynamics at different pH conditions for 150 ns. A well defined correlation was observed between experimental and computational studies. This work highlights the significance of structural dependence of pH for wide implications in protein-protein interaction, biological function and drug design procedures.