Lactate enhances motility of tumor cells and inhibits monocyte migration and cytokine release

Wireless Battery-free and Fully Implantable Organ Interfaces

Advances in soft materials, miniaturized electronics, sensors, stimulators, radios, and battery-free power supplies are resulting in a new generation of fully implantable organ interfaces that leverage volumetric reduction and soft mechanics by eliminating electrochemical power storage. This device class offers the ability to provide high-fidelity readouts of physiological processes, enables stimulation, and allows control over organs to realize new therapeutic and diagnostic paradigms. Driven by seamless integration with connected infrastructure, these devices enable personalized digital medicine. Key to advances are carefully designed material, electrophysical, electrochemical, and electromagnetic systems that form implantables with mechanical properties closely matched to the target organ to deliver functionality that supports high-fidelity sensors and stimulators. The elimination of electrochemical power supplies enables control over device operation, anywhere from acute, to lifetimes matching the target subject with physical dimensions that supports imperceptible operation. This review provides a comprehensive overview of the basic building blocks of battery-free organ interfaces and related topics such as implantation, delivery, sterilization, and user acceptance. State of the art examples categorized by organ system and an outlook of interconnection and advanced strategies for computation leveraging the consistent power influx to elevate functionality of this device class over current battery-powered strategies is highlighted.

Prognostic implication of a novel lactate score correlating with immunotherapeutic responses in pan-cancer

A thorough assessment of lactate-related genes (LRGs) in different types of human cancers is currently lacking. To elucidate the molecular landscape of LRGs, we conducted a comprehensive analysis using genomic, mRNA, and microRNA expression profiles and developed a lactate score model using the least absolute shrinkage and selection operator (LASSO) algorithm. We found that our lactate score could be a prognostic marker instead of LDHA for several cancer patients who possess high-frequency variants in LRGs. The lactate score also demonstrated an association with CD8+ T cells infiltration in multiple cancer types. Furthermore, our findings indicate that the lactate score holds promise as a potential biomarker for immunotherapy in patients with bladder cancer (BLCA) and skin cutaneous melanoma (SKCM). Among the seventeen genes of the lactate score model, PDP1 showed the strongest positive correlation with lactate score and the potential as a standalone biomarker for prognosis. In general, our study has yielded crucial insights into the potential application of the lactate score as a predictive biomarker for both survival outcomes and the response to immunotherapy. By recognizing the prognostic significance of lactate metabolism, we open avenues for further investigations aimed at harnessing the therapeutic potential of lactate.

Pyruvate Kinase Differentially Alters Metabolic Signatures during Head and Neck Carcinogenesis

During glycolysis, the muscle isoform of pyruvate kinase PKM2 produces ATP in exchange for dephosphorylation of phosphoenolpyruvate (PEP) into pyruvate. PKM2 has been considered as a tumor-promoting factor in most cancers, whereas the regulatory role of PKM2 during head and neck carcinogenesis remained to be delineated. PKM2 mRNA and protein expression was examined in head and neck tumorous specimens. The role of PKM2 in controlling cellular malignancy was determined in shRNA-mediated PKM2-deficient head and neck squamous cell carcinoma (HNSC) cells. In agreement with the results in other cancers, PKM2 expression is enriched in both mouse and human HNSC tissues. Nevertheless, PKM2 mRNA expression reversely correlated with tumor stage, and greater recurrence-free survival rates are evident in the PKM2high HNSC population, arguing that PKM2 may be tumor-suppressive. Multifaceted analyses showed a greater in vivo xenografic tumor growth and an enhanced cisplatin resistance in response to PKM2 loss, whereas PKM2 silencing led to reduced cell motility. At the molecular level, metabolic shifts towards mitochondrial metabolism and activation of oncogenic Protein kinase B (PKB/Akt) and extracellular signal-regulated kinase (ERK) signals were detected in PKM2-silencing HNSC cells. In sum, our findings demonstrated that PKM2 differentially modulated head and neck tumorigenicity via metabolic reprogramming.

Knowledge mapping and current trends of Warburg effect in the field of cancer

Background

Since abnormal aerobic glycolysis was first identified in cancer cells, many studies have focused on its mechanisms. The purpose of this study was to analyze the global research status of the Warburg effect in cancer using bibliometrics.

Methods

Articles published from 01 January 2013 to 31 December 2022 (n=2,067) were retrieved from the Web of Science core collection database and analyzed using VOSviewer and CiteSpace software.

Results

Over the past decade, there was an overall increase in the number of annual publications. China was the most productive country with 790 articles, while the United States received the most citations, with 25,657 citations in total. Oncotarget was the most productive and most cited journal, with 99 articles and 4,191 citations, respectively. International cooperation was common, with the USA cooperating most with other countries. Lactate metabolism, citrate production, and non-coding RNAs related to the Warburg effect have received increasing attention in cancer research. These areas may become future research trends.

Conclusion

The study findings help summarize the research status and hotspots of the Warburg effect cancer, and will inform subsequent research.

Combined signature of N7-methylguanosine regulators with their related genes and the tumor microenvironment: a prognostic and therapeutic biomarker for breast cancer

Background

Identifying predictive markers for breast cancer (BC) prognosis and immunotherapeutic responses remains challenging. Recent findings indicate that N7-methylguanosine (m7G) modification and the tumor microenvironment (TME) are critical for BC tumorigenesis and metastasis, suggesting that integrating m7G modifications and TME cell characteristics could improve the predictive accuracy for prognosis and immunotherapeutic responses.

Methods

We utilized bulk RNA-sequencing data from The Cancer Genome Atlas Breast Cancer Cohort and the GSE42568 and GSE146558 datasets to identify BC-specific m7G-modification regulators and associated genes. We used multiple m7G databases and RNA interference to validate the relationships between BC-specific m7G-modification regulators (METTL1 and WDR4) and related genes. Single-cell RNA-sequencing data from GSE176078 confirmed the association between m7G modifications and TME cells. We constructed an m7G-TME classifier, validated the results using an independent BC cohort (GSE20685; n = 327), investigated the clinical significance of BC-specific m7G-modifying regulators by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, and performed tissue-microarray assays on 192 BC samples.

Results

Immunohistochemistry and RT-qPCR results indicated that METTL1 and WDR4 overexpression in BC correlated with poor patient prognosis. Moreover, single-cell analysis revealed relationships between m7G modification and TME cells, indicating their potential as indicators of BC prognosis and treatment responses. The m7G-TME classifier enabled patient subgrouping and revealed significantly better survival and treatment responses in the m7Glow+TMEhigh group. Significant differences in tumor biological functions and immunophenotypes occurred among the different subgroups.

Conclusions

The m7G-TME classifier offers a promising tool for predicting prognosis and immunotherapeutic responses in BC, which could support personalized therapeutic strategies.

Effect of serum lactate dehydrogenase-to-albumin ratio (LAR) on the short-term outcomes and long-term prognosis of colorectal cancer after radical surgery

BACKGROUND

Whether serum lactate dehydrogenase-to-albumin ratio (LAR) influenced the outcomes of colorectal cancer (CRC) patients after radical surgery remained unclear. Therefore, this study sought to examine how LAR influences the short-term and long-term outcomes of CRC patients who have undergone radical surgery.

METHODS

This study retrospectively included CRC patients who underwent radical resection between January 2011 and January 2020. We compared short-term outcomes, as well as overall survival (OS) and disease-free survival (DFS), among various groups. Both univariate and multivariate logistic regression analyses were utilized to pinpoint independent risk factors associated with overall complications and major complications. Moreover, Cox regression analysis were conducted for OS and DFS. Odds ratio (OR) and Hazard ratio (HR) were adjusted.

RESULTS

This study encompassed a cohort of 3868 patients. 3440 patients were in the low LAR group and 428 patients constituted the high LAR group. In the high LAR group, patients experienced significantly longer operative times (p < 0.01), larger intraoperative blood loss (p < 0.01), and extended postoperative hospital stays (p < 0.01). Additionally, the incidence of both overall complications (p < 0.01) and major complications (p < 0.01) was higher in the high LAR group compared to the low LAR group. Furthermore, LAR was emerged as an independent prognostic factor for overall complications [OR/95% CI: (1.555/1.237 to 1.954), p < 0.01] and major complications [OR/95% CI: (2.178/1.279 to 3.707), p < 0.01]. As for long-term survival, the high LAR group had worse OS in stage II (p < 0.01) and stage III (p < 0.01). In both stage II (p < 0.01) and stage III (p < 0.01), the high LAR group exhibited poorer DFS. Additionally, according to Cox regression analysis, LAR was identified as an independent predictor for both OS [HR/95% CI: (1.930/1.554 to 2.398), p < 0.01] and DFS [HR/95% CI: (1.750/1.427 to 2.146), p < 0.01].

CONCLUSION

LAR emerged as an independent predictor not only for overall complications and major complications but also for both OS and DFS, highlighting its significance and deserving the attention of surgeons.

The crosstalking of lactate-Histone lactylation and tumor

Lactate was once considered to be a by-product of energy metabolism, but its unique biological value was only gradually explored with the advent of the Warburg effect. As an end product of glycolysis, lactate can act as a substrate for energy metabolism, a signal transduction molecule, a regulator of the tumor microenvironment and immune cells, and a regulator of the deubiquitination of specific enzymes, and is involved in various biological aspects of tumor regulation, including energy shuttling, growth and invasion, angiogenesis and immune escape. Furthermore, we describe a novel lactate-dependent epigenetic modification, namely histone lactylation modification, and review the progress of its study in tumors, mainly involving the reprogramming of tumor phenotypes, regulation of related gene expression, mediation of the glycolytic process in tumor stem cells (CSCs) and influence on the tumor immune microenvironment. The study of epigenetic regulation of tumor genes by histone modification is still in its infancy, and we expect that by summarizing the effects of lactate and histone modification on tumor and related gene regulation, we will clarify the scientific significance of future histone modification studies and the problems to be solved, and open up new fields for targeted tumor therapy.

Tumour microenvironment as a predictive factor for immunotherapy in non-muscle-invasive bladder cancer

Bladder cancer (BC) can be divided into two subgroups depending on invasion of the muscular layer: non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Its aggressiveness is associated, inter alia, with genetic aberrations like losses of 1p, 6q, 9p, 9q and 13q; gain of 5p; or alterations in the p53 and p16 pathways. Moreover, there are reported metabolic disturbances connected with poor diagnosis-for example, enhanced aerobic glycolysis, gluconeogenesis or haem catabolism.Currently, the primary way of treatment method is transurethral resection of the bladder tumour (TURBT) with adjuvant Bacillus Calmette-Guérin (BCG) therapy for NMIBC or radical cystectomy for MIBC combined with chemotherapy or immunotherapy. However, intravesical BCG immunotherapy and immune checkpoint inhibitors are not efficient in every case, so appropriate biomarkers are needed in order to select the proper treatment options. It seems that the success of immunotherapy depends mainly on the tumour microenvironment (TME), which reflects the molecular disturbances in the tumour. TME consists of specific conditions like hypoxia or local acidosis and different populations of immune cells including tumour-infiltrating lymphocytes, natural killer cells, neutrophils and B lymphocytes, which are responsible for shaping the response against tumour neoantigens and crucial pathways like the PD-L1/PD-1 axis.In this review, we summarise holistically the impact of the immune system, genetic alterations and metabolic changes that are key factors in immunotherapy success. These findings should enable better understanding of the TME complexity in case of NMIBC and causes of failures of current therapies.

Down-regulation of ALDOB during metabolic reprogramming mediates malignant behavior in hepatocellular carcinoma and insensitivity to postoperative adjuvant transarterial chemoembolization

BACKGROUND

Postoperative transarterial chemoembolization (PA-TACE) is an effective adjuvant therapy for preventing early postoperative recurrence of hepatocellular carcinoma (HCC); however, many patients are insensitive to it. Therefore, the present study aimed to explore the in-depth reasons for PA-TACE resistance and provide a reliable basis for selecting patients who will benefit the most from PA-TACE.

METHODS

The unique gene expression profiles of primary tumors from PA-TACE-sensitive or -insensitive patients were analyzed using microarray data. Combined differential expression analysis, gene set enrichment analysis (GSEA), and weighted correlation network analysis (WGCNA) were used to screen for potential drivers of PA-TACE insensitivity. The expression of ALDOB was silenced or overexpressed in hepatoma cell lines, and changes in glycolytic activity, cycle, apoptosis, and malignant biological phenotypes were observed under normoxia and hypoxia. Finally, an animal model was constructed to verify the effects of ALDOB dysregulation on the tumorigenic ability of HCC cells in vivo.

RESULTS

The inhibition of ALDOB promoted the up-regulation of Ki67 expression, and glycolytic activity was significantly enhanced. Moreover, the proliferation, invasion, and migration capabilities were increased in HCC cells and even worse in hypoxia. This advantage of malignant behavior was also validated using in vivo models.

CONCLUSION

Down-regulation of ALDOB may underlie the metabolic reprogramming observed in HCC by promoting the malignant behavior of HCC cells. Hypoxia and ALDOB down-regulation acted additively, which was closely related to PA-TACE insensitivity. The use of ALDOB and Ki67 as a combined marker has the potential to identify the 'PA-TACE beneficiary population'.

Characterization of a lactate metabolism-related signature for evaluation of immune features and prediction prognosis in glioma

Background

Glioma is one of the most typical tumors in the central nervous system with a poor prognosis, and the optimal management strategy remains controversial. Lactate in the tumor microenvironment is known to promote cancer progression, but its impact on clinical outcomes of glioma is largely unknown.

Methods

Glioma RNA-seq data were obtained from TCGA and GCGA databases. Lactate metabolism genes (LMGs) were then evaluated to construct an LMG model in glioma using Cox and LASSO regression. Immune cell infiltration, immune checkpoint gene expression, enriched pathways, genetic alteration, and drug sensitivity were compared within the risk subgroups. Based on the risk score and clinicopathological features, a nomogram was developed to predict prognosis in patients with glioma.

Results

Five genes (LDHA, LDHB, MRS2, SL16A1, and SL25A12) showed a good prognostic value and were used to construct an LMG-based risk score. This risk score was shown as an independent prognostic factor with good predictive power in both training and validation cohorts (p < 0.001). The LMG signature was found to be correlated with the expression of immune checkpoint genes and immune infiltration and could shape the tumor microenvironment. Genetic alteration, dysregulated metabolism, and tumorigenesis pathways could be the underlying contributing factors that affect LMG risk stratification. The patients with glioma in the LMG high-risk group showed high sensitivity to EGFR inhibitors. In addition, our nomogram model could effectively predict overall survival with an area under the curve value of 0.894.

Conclusion

We explored the characteristics of LMGs in glioma and proposed an LMG-based signature. This prognostic model could predict the survival of patients with glioma and help clinical oncologists plan more individualized and effective therapeutic regimens.

NF-κB mediated regulation of tumor cell proliferation in hypoxic microenvironment

Hypoxia is caused by a cancer-promoting milieu characterized by persistent inflammation. NF-κB and HIF-1α are critical participants in this transition. Tumor development and maintenance are aided by NF-κB, while cellular proliferation and adaptability to angiogenic signals are aided by HIF-1α. Prolyl hydroxylase-2 (PHD-2) has been hypothesized to be the key oxygen-dependent regulator of HIF-1α and NF-transcriptional B's activity. Without low oxygen levels, HIF-1α is degraded by the proteasome in a process dependent on oxygen and 2-oxoglutarate. As opposed to the normal NF-κB activation route, where NF-κB is deactivated by PHD-2-mediated hydroxylation of IKK, this method actually activates NF-κB. HIF-1α is protected from degradation by proteasomes in hypoxic cells, where it then activates transcription factors involved in cellular metastasis and angiogenesis. The Pasteur phenomenon causes lactate to build up inside the hypoxic cells. As part of a process known as lactate shuttle, MCT-1 and MCT-4 cells help deliver lactate from the blood to neighboring, non-hypoxic tumour cells. Non-hypoxic tumour cells use lactate, which is converted to pyruvate, as fuel for oxidative phosphorylation. OXOPHOS cancer cells are characterized by a metabolic switch from glucose-facilitated oxidative phosphorylation to lactate-facilitated oxidative phosphorylation. Although PHD-2 was found in OXOPHOS cells. There is no clear explanation for the presence of NF-kappa B activity. The accumulation of the competitive inhibitor of 2-oxo-glutarate, pyruvate, in non-hypoxic tumour cells is well established. So, we conclude that PHD-2 is inactive in non-hypoxic tumour cells due to pyruvate-mediated competitive suppression of 2-oxo-glutarate. This results in canonical activation of NF-κB. In non-hypoxic tumour cells, 2-oxoglutarate serves as a limiting factor, rendering PHD-2 inactive. However, FIH prevents HIF-1α from engaging in its transcriptional actions. Using the existing scientific literature, we conclude in this study that NF-κB is the major regulator of tumour cell growth and proliferation via pyruvate-mediated competitive inhibition of PHD-2.

Antitumor effects of lactate transport inhibition on esophageal adenocarcinoma cells

As a consequence of altered glucose metabolism, cancer cell intake is increased, producing large amounts of lactate which is pumped out the cytosol by monocarboxylate transporters (MCTs). MCT 1 and MCT4 are frequently overexpressed in tumors, and recently, MCT inhibition has been reported to exert antineoplastic effects. In the present study, MCT1 and MCT4 levels were assessed in esophageal adenocarcinoma (EAC) cells and the effects of the MCT-1 selective inhibitor AZD3965, hypoxia, and a glucose overload were evaluated in vitro. Two EAC cell lines (OE33 and OACM5.1C) were treated with AZD3965 (10-100 nM) under different conditions (normoxia/hypoxia) and also different glucose concentrations, and parameters of cytotoxicity, oxidative stress, intracellular pH (pHi), and lactate levels were evaluated. MCT1 was present in both cell lines whereas MCT4 was expressed in OE33 cells and only in a small proportion of OACM5.1C cells. Glucose addition did not have any effect on apoptosis nor cell proliferation. AZD3965 increased apoptosis and reduced proliferation of OACM5.1C cells, effects which were abrogated when cells were growing in hypoxia. MCT1 inhibition increased intracellular lactate levels in all the cells evaluated, but this increase was higher in cells expressing only MCT1 and did not affect oxidative stress. AZD3965 induced a decrease in pHi of cells displaying low levels of MCT4 and also increased the sodium/hydrogen exchanger 1 (NHE-1) expression on these cells. These data provide in vitro evidence supporting the potential of MCT inhibitors as novel antineoplastic drugs for EAC and highlight the importance of achieving a complete MCT inhibition.

Interaction between glycolysis‒cholesterol synthesis axis and tumor microenvironment reveal that gamma-glutamyl hydrolase suppresses glycolysis in colon cancer

Background

Metabolic reprogramming is a feature of cancer. However, colon cancer subtypes based on the glycolysis‒cholesterol synthesis axis have not been identified, and little is known about connections between metabolic features and the tumor microenvironment.

Methods

Data for 430 colon cancer cases were extracted from The Cancer Genome Atlas, including transcriptome data, clinical information, and survival outcomes. Glycolysis and cholesterol synthesis-related gene sets were obtained from the Molecular Signatures Database for a gene set variation analysis. The relationship between the genomic landscape and immune landscape were investigated among four metabolic subtypes. Hub genes were determined. The clinical significance of candidate hub gene was evaluated in 264 clinical samples and potential functions were validated in vitro and in vivo.

Results

Colon cancer cases were clustered into four metabolic subtypes: quiescent, glycolytic, cholesterogenic, and mixed. The metabolic subtypes differed with respect to the immune score, stromal score, and estimate score using the ESTIMATE algorithm, cancer-immunity cycle, immunomodulator signatures, and signatures of immunotherapy responses. Patients in the cholesterogenic group had better survival outcomes than those for other subtypes, especially glycolytic. The glycolytic subtype was related to unfavorable clinical characteristics, including high mutation rates in TTN, APC, and TP53, high mutation burden, vascular invasion, right colon cancer, and low-frequency microsatellite instability. GGH, CACNG4, MME, SLC30A2, CKMT2, SYN3, and SLC22A31 were identified as differentially expressed both in glycolytic-cholesterogenic subgroups as well as between colon cancers and healthy samples, and were involved in glycolysis‒cholesterol synthesis. GGH was upregulated in colon cancer; its high expression was correlated with CD4⁺ T cell infiltration and longer overall survival and it was identified as a favorable independent prognostic factor. The overexpression of GGH in colon cancer-derived cell lines (SW48 and SW480) inhibited PKM, GLUT1, and LDHA expression and decreased the extracellular lactate content and intracellular ATP level. The opposite effects were obtained by GGH silencing. The phenotype associated with GGH was also validated in a xenograft nude mouse model.

Conclusions

Our results provide insight into the connection between metabolism and the tumor microenvironment in colon cancer and provides preliminary evidence for the role of GGH, providing a basis for subsequent studies.

An Update on the Metabolic Landscape of Oncogenic Viruses

Viruses play an important role in cancer development as about 12% of cancer types are linked to viral infections. Viruses that induce cellular transformation are known as oncoviruses. Although the mechanisms of viral oncogenesis differ between viruses, all oncogenic viruses share the ability to establish persistent chronic infections with no obvious symptoms for years. During these prolonged infections, oncogenic viruses manipulate cell signaling pathways that control cell cycle progression, apoptosis, inflammation, and metabolism. Importantly, it seems that most oncoviruses depend on these changes for their persistence and amplification. Metabolic changes induced by oncoviruses share many common features with cancer metabolism. Indeed, viruses, like proliferating cancer cells, require increased biosynthetic precursors for virion production, need to balance cellular redox homeostasis, and need to ensure host cell survival in a given tissue microenvironment. Thus, like for cancer cells, viral replication and persistence of infected cells frequently depend on metabolic changes. Here, we draw parallels between metabolic changes observed in cancers or induced by oncoviruses, with a focus on pathways involved in the regulation of glucose, lipid, and amino acids. We describe whether and how oncoviruses depend on metabolic changes, with the perspective of targeting them for antiviral and onco-therapeutic approaches in the context of viral infections.

Mechanical Force Modulates Alveolar Bone Marrow Mesenchymal Cells Characteristics for Bone Remodeling during Orthodontic Tooth Movement through Lactate Production

Orthodontic tooth movement (OTM) relies on mechanical force-induced bone remodeling. As a metabolic intermediate of glycolysis, lactate has recently been discovered to participate in bone remodeling by serving as a signaling molecule. However, whether lactate could respond to mechanical stimulus during OTM, as well as whether lactate has an impact on the alveolar bone remodeling during orthodontics, remain to be further elucidated. In the current study, we observed physiologically elevated production of lactate along with increased osteogenic differentiation, proliferation, and migration of alveolar bone marrow mesenchymal cells (ABMMCs) under mechanical force. Inhibition of lactate, induced by cyclic mechanical stretch by GNE-140, remarkably suppressed the osteogenic differentiation, proliferation, and migration, yet enhanced apoptosis of ABMMCs. Mechanistically, these regulatory effects of lactate were mediated by histone lactylation. Taken together, our results suggest that force-induced lactate is involved in controlling bone remodeling-related cellular activities in ABMMCs and plays a vital role in the alveolar bone remodeling during OTM. Our findings indicate that lactate might be a critical modulator for alveolar bone remodeling during OTM, providing a novel therapeutic target for the purpose of more effectively controlling tooth movement and improving the stability of orthodontic results.

Lactate causes downregulation of Helicobacter pylori adhesin genes sabA and labA while dampening the production of proinflammatory cytokines

Chronic inflammation induced by Helicobacter pylori is strongly associated with gastric cancer development, which is influenced by both bacterial virulence and host genetics. The sialic acid-binding adhesin SabA and the MUC5AC-binding adhesin LabA are important H. pylori virulence factors that facilitate adhesion of the bacterium, which is a crucial step in colonization. Lactate utilization has been reported to play a key role in the pathogenicity of different bacterial species. However, this is poorly understood in H. pylori. In this study, we investigated the effect of lactate on H. pylori adhesin gene expression and the regulation of host inflammatory cytokines. We show that the bacterial adhesins SabA and LabA were downregulated at the transcriptional level during incubation of H. pylori with lactate. Downregulation of sabA required the involvement of the two-component system ArsRS, while labA was regulated via the CheA/CheY system, indicating differences in the regulation of these genes in response to lactate. The levels of the proinflammatory cytokines TNF and IL-6 in H. pylori-stimulated macrophages were reduced when lactate was present. Interestingly, glucose did not prevent the secretion of these cytokines. Taken together, our data suggest that lactate affects H. pylori adhesin gene expression and the host response upon infection.

Oncometabolism: A Paradigm for the Metabolic Remodeling of the Failing Heart

Heart failure is associated with profound alterations in cardiac intermediary metabolism. One of the prevailing hypotheses is that metabolic remodeling leads to a mismatch between cardiac energy (ATP) production and demand, thereby impairing cardiac function. However, even after decades of research, the relevance of metabolic remodeling in the pathogenesis of heart failure has remained elusive. Here we propose that cardiac metabolic remodeling should be looked upon from more perspectives than the mere production of ATP needed for cardiac contraction and relaxation. Recently, advances in cancer research have revealed that the metabolic rewiring of cancer cells, often coined as oncometabolism, directly impacts cellular phenotype and function. Accordingly, it is well feasible that the rewiring of cardiac cellular metabolism during the development of heart failure serves similar functions. In this review, we reflect on the influence of principal metabolic pathways on cellular phenotype as originally described in cancer cells and discuss their potential relevance for cardiac pathogenesis. We discuss current knowledge of metabolism-driven phenotypical alterations in the different cell types of the heart and evaluate their impact on cardiac pathogenesis and therapy.

The Mechanisms of Systemic Inflammatory and Immunosuppressive Acute-on-Chronic Liver Failure and Application Prospect of Single-Cell Sequencing

Acute-on-chronic liver failure (ACLF) is a complex clinical syndrome, and patients often have high short-term mortality. It occurs with intense systemic inflammation, often accompanied by a proinflammatory event (such as infection or alcoholic hepatitis), and is closely related to single or multiple organ failure. Liver inflammation begins when innate immune cells (such as Kupffer cells (KCs)) are activated by binding of pathogen-associated molecular patterns (PAMPs) from pathogenic microorganisms or damage-associated molecular patterns (DAMPs) of host origin to their pattern recognition receptors (PRRs). Activated KCs can secrete inflammatory factors as well as chemokines and recruit bone marrow-derived cells such as neutrophils and monocytes to the liver to enhance the inflammatory process. Bacterial translocation may contribute to ACLF when there are no obvious precipitating events. Immunometabolism plays an important role in the process (including mitochondrial dysfunction, amino acid metabolism, and lipid metabolism). The late stage of ACLF is mainly characterized by immunosuppression. In this process, the dysfunction of monocyte and macrophage is reflected in the downregulation of HLA-DR and upregulation of MER tyrosine kinase (MERTK), which weakens the antigen presentation function and reduces the secretion of inflammatory cytokines. We also describe the specific function of bacterial translocation and the gut-liver axis in the process of ACLF. Finally, we also describe the transcriptomics in HBV-ACLF and the recent progress of single-cell RNA sequencing as well as its potential application in the study of ACLF in the future, in order to gain a deeper understanding of ACLF in terms of single-cell gene expression.

Repurposing an Antiepileptic Drug for the Treatment of Glioblastoma

PURPOSE

Glioblastoma multiforme (GBM) is a grade IV, highly proliferative, and malignant form of brain tumor with a 5-year survival rate at ~ 5%. Current treatment strategies for GBM include surgery, radiation, and chemotherapy. Major challenges in GBM management include difficulties in surgical resection due to brain's vital functions and GBM metastasis, development of resistance to temozolomide (TMZ), and protection of tumor by blood brain barrier (BBB). Therefore, we aimed to discover a novel therapeutic for GBM by targeting its metabolic reprogramming.

METHOD

We screened metabolic inhibitors by their effects on GBM cell viability by MTT assay. We discovered an FDA-approved drug stiripentol (STP) in our screening of metabolic inhibitors in GBM cells. STP is used for Dravet syndrome (a rare epilepsy). We further tested efficacy of STP using proliferation assay, clonogenic assay, in vitro migration assay, cell cycle assay, apoptosis assay, and in U87 3D spheroids. We also tested the toxicity of STP, and combinations used in the study on normal human dermal fibroblasts.

RESULTS

STP was effective in decreasing GBM cell viability, proliferation, clonogenic ability, and migration. Moreover, cell cycle changes were involved but robust apoptosis was absent in STP's anticancer effects. STP was effective in 3D spheroid models, and in TMZ-resistant cells. STP showed additive or synergistic effect with TMZ in different anticancer assays on GBM cells and was considerably less toxic in normal cells.

CONCLUSION

Our results indicate that STP can be an effective GBM therapeutic that enhances the effects of TMZ on GBM cells. Importantly, STP reduced viability of TMZ-resistant cells. Our results warrant further studies in the mechanistic basis of STP's effects on GBM cells and the preclinical potential of STP in animal models.

Targeting Glucose Metabolism Enzymes in Cancer Treatment: Current and Emerging Strategies

Simple Summary

Reprogramming of glucose metabolism is a hallmark of cancer and can be targeted by therapeutic agents. Some metabolism regulators, such as ivosidenib and enasidenib, have been approved for cancer treatment. Currently, more advanced and effective glucose metabolism enzyme-targeted anticancer drugs have been developed. Furthermore, some natural products have shown efficacy in killing tumor cells by regulating glucose metabolism, offering novel therapeutic opportunities in cancer. However, most of them have failed to be translated into clinical applications due to low selectivity, high toxicity, and side effects. Recent studies suggest that combining glucose metabolism modulators with chemotherapeutic drugs, immunotherapeutic drugs, and other conventional anticancer drugs may be a future direction for cancer treatment.

Abstract

Reprogramming of glucose metabolism provides sufficient energy and raw materials for the proliferation, metastasis, and immune escape of cancer cells, which is enabled by glucose metabolism-related enzymes that are abundantly expressed in a broad range of cancers. Therefore, targeting glucose metabolism enzymes has emerged as a promising strategy for anticancer drug development. Although several glucose metabolism modulators have been approved for cancer treatment in recent years, some limitations exist, such as a short half-life, poor solubility, and numerous adverse effects. With the rapid development of medicinal chemicals, more advanced and effective glucose metabolism enzyme-targeted anticancer drugs have been developed. Additionally, several studies have found that some natural products can suppress cancer progression by regulating glucose metabolism enzymes. In this review, we summarize the mechanisms underlying the reprogramming of glucose metabolism and present enzymes that could serve as therapeutic targets. In addition, we systematically review the existing drugs targeting glucose metabolism enzymes, including small-molecule modulators and natural products. Finally, the opportunities and challenges for glucose metabolism enzyme-targeted anticancer drugs are also discussed. In conclusion, combining glucose metabolism modulators with conventional anticancer drugs may be a promising cancer treatment strategy.

Identification of novel lactate metabolism signatures and molecular subtypes for prognosis in hepatocellular carcinoma

Background: Evidence has shown that lactate, an immune signaling molecule, is associated with hepatocellular carcinoma (HCC) progression and immune suppression. Therefore, identifying lactate metabolism-related molecules is a promising therapeutic strategy to inhibit the development of HCC and overcome chemotherapy resistance. Long noncoding RNAs (lncRNAs) are related to tumorigenesis and metastasis. Hence, verifying the molecular subtypes of lncRNAs related to lactate metabolism will play a critical role in managing HCC.

Methods: Based on HCC data in The Cancer Genome Atlas (TCGA), lactate metabolic pathway-related genes were enriched by gene collection and enrichment analysis (GSEA). Lactate metabolism-related lncRNAs (LM_lncRNAs) were identified by correlation analysis, HCC molecular subtypes were determined using nonnegative matrix factorization (NMF) clustering, and the response of the three subtypes to chemotherapeutics was further evaluated using the Genomic Tumor Sensitive Cell Line (GDSC) dataset. LM_lncRNAs were examined via Lasso-Cox regression analysis to determine prognosis for patients. A Nomagram plot was used to predict patient survival time.

Results: Three molecular subtypes of HCC were identified. The survival rate of patients with C1 subtype was higher than that of those with C2 and C3. Additionally, patients with C3 subtype have higher levels of immune cell infiltration and high expression of genes related to immune checkpoints. The GDSC results indicated that patients with C3 subtypes were more sensitive to chemotherapy drugs such as sorafenib and sunitinib. The prognostic risk assessment model consisted of six risk factors (AC034229.4, AC131009.1, MYOSLID, AC008667.1, AC012073.1, AC068025.1) and two protective factors (LINC00402 and AC103858.1). Based on Kaplan-Meier analysis, low-risk HCC patients had a high survival rate, and the receiver operating characteristic curve (ROC), calibration curve, and C-index confirmed good prediction ability.

Conclusion: In this study, the molecular subtyping method and prediction model of lactate metabolism-related lncRNAs (LM_lncRNAs) were constructed for the prognosis of HCC patients. This work demonstrated the potential targets of LM_lncRNAs and provided a novel perspective and therapeutic paradigm for future clinical translation.

A Novel Metabolism-Related Gene Signature for Predicting the Prognosis of HBV-Infected Hepatocellular Carcinoma

Metabolic reprogramming is one of the crucial hallmarks of cancer. Hepatocellular carcinoma (HCC) resulting from hepatitis B has various altered metabolic features. However, the impact of such alterations on the tumor microenvironment (TME) and immunotherapy efficacy is still unclear. Here, a prognostic signature of metabolism-related gene (MRG) composition was constructed, and the immune profile of different subgroups and potential response to immunotherapy were described. Based on the HCC gene dataset, we used weighted gene coexpression network analysis for identifying MRGs linked to hepatitis B. An MRG prognostic index (MRGPI) with two genes, ATIC and KIF2C, was constructed using Cox regression analysis, an independent prognostic factor. In addition, the model was validated using the GEO dataset. The immune profile and prediction of HCC response to immunotherapy in different subgroups were analyzed using CIBERSORT and TIDE. Based on the outcomes, the distributions of memory B cells, monocytes, resting mast cells, and M0 macrophages in TME were different with a greater benefit of immunotherapy in the low MRGPI risk group. In addition, the MRGPI risk groups showed substantial differences in sensitivity to conventional drug therapy. This study concludes that MRGPI is an effective biomarker for predicting the prognoses of patients with HCC resulting from hepatitis B virus infections and determining the efficacy of immunotherapy and conventional medical therapy.

Bisphenols A and S Alter the Bioenergetics and Behaviours of Normal Urothelial and Bladder Cancer Cells

Bisphenol A (BPA) and bisphenol S (BPS) are used in the production of plastics. These endocrine disruptors can be released into the environment and food, resulting in the continuous exposure of humans to bisphenols (BPs). The bladder urothelium is chronically exposed to BPA and BPS due to their presence in human urine samples. BPA and BPS exposure has been linked to cancer progression, especially for hormone-dependent cancers. However, the bladder is not recognized as a hormone-dependent tissue. Still, the presence of hormone receptors on the urothelium and their role in bladder cancer initiation and progression suggest that BPs could impact bladder cancer development. The effects of chronic exposure to BPA and BPS for 72 h on the bioenergetics (glycolysis and mitochondrial respiration), proliferation and migration of normal urothelial cells and non-invasive and invasive bladder cancer cells were evaluated. The results demonstrate that chronic exposure to BPs decreased urothelial cells' energy metabolism and properties while increasing them for bladder cancer cells. These findings suggest that exposure to BPA and BPS could promote bladder cancer development with a potential clinical impact on bladder cancer progression. Further studies using 3D models would help to understand the clinical consequences of this exposure.

Microenvironment in Oral Potentially Malignant Disorders: Multi-Dimensional Characteristics and Mechanisms of Carcinogenesis

Oral potentially malignant disorders (OPMDs) are a group of diseases involving the oral mucosa and that have a risk of carcinogenesis. The microenvironment is closely related to carcinogenesis and cancer progression by regulating the immune response, cell metabolic activities, and mechanical characteristics. Meanwhile, there are extensive interactions between the microenvironments that remodel and provide favorable conditions for cancer initiation. However, the changes, exact roles, and interactions of microenvironments during the carcinogenesis of OPMDs have not been fully elucidated. Here, we present an updated landscape of the microenvironments in OPMDs, emphasizing the changes in the immune microenvironment, metabolic microenvironment, mechanical microenvironment, and neural microenvironment during carcinogenesis and their carcinogenic mechanisms. We then propose an immuno–metabolic–mechanical–neural interaction network to describe their close relationships. Lastly, we summarize the therapeutic strategies for targeting microenvironments, and provide an outlook on future research directions and clinical applications. This review depicts a vivid microenvironment landscape and sheds light on new strategies to prevent the carcinogenesis of OPMDs.

Glucometabolic reprogramming: From trigger to therapeutic target in hepatocellular carcinoma

Glucose, the central macronutrient, releases energy as ATP through carbon bond oxidation and supports various physiological functions of living organisms. Hepatocarcinogenesis relies on the bioenergetic advantage conferred by glucometabolic reprogramming. The exploitation of reformed metabolism induces a uniquely inert environment conducive to survival and renders the hepatocellular carcinoma (HCC) cells the extraordinary ability to thrive even in the nutrient-poor tumor microenvironment. The rewired metabolism also confers a defensive barrier which protects the HCC cells from environmental stress and immune surveillance. Additionally, targeted interventions against key players of HCC metabolic and signaling pathways provide promising prospects for tumor therapy. The active search for novel drugs based on innovative mutation targets is warranted in the future for effectively treating advanced HCC and the preoperative downstage. This article aims to review the regulatory mechanisms and therapeutic value of glucometabolic reprogramming on the disease progression of HCC, to gain insights into basic and clinical research.

The Significance of MicroRNAs in the Molecular Pathology of Brain Metastases

Brain metastases are the most frequent intracranial tumors in adults and the cause of death in almost one-fourth of cases. The incidence of brain metastases is steadily increasing. The main reason for this increase could be the introduction of new and more efficient therapeutic strategies that lead to longer survival but, at the same time, cause a higher risk of brain parenchyma infiltration. In addition, the advances in imaging methodology, which provide earlier identification of brain metastases, may also be a reason for the higher recorded number of patients with these tumors. Metastasis is a complex biological process that is still largely unexplored, influenced by many factors and involving many molecules. A deeper understanding of the process will allow the discovery of more effective diagnostic and therapeutic approaches that could improve the quality and length of patient survival. Recent studies have shown that microRNAs (miRNAs) are essential molecules that are involved in specific steps of the metastatic cascade. MiRNAs are endogenously expressed small non-coding RNAs that act as post-transcriptional regulators of gene expression and thus regulate most cellular processes. The dysregulation of these molecules has been implicated in many cancers, including brain metastases. Therefore, miRNAs represent promising diagnostic molecules and therapeutic targets in brain metastases. This review summarizes the current knowledge on the importance of miRNAs in brain metastasis, focusing on their involvement in the metastatic cascade and their potential clinical implications.

Metabolic Reprogramming Induces Macrophage Polarization in the Tumor Microenvironment

Macrophages are one of the most important cells in the innate immune system, they are converted into two distinct subtypes with completely different molecular phenotypes and functional features under different stimuli of the microenvironment: M1 macrophages induced by IFN-γ/lipopolysaccharides(LPS) and M2 macrophages induced by IL-4/IL-10/IL-13. Tumor-associated macrophages (TAMs) differentiate from macrophages through various factors in the tumor microenvironment (TME). TAMs have the phenotype and function of M2 macrophages and are capable of secreting multiple cytokines to promote tumor progression. Both tumor cells and macrophages can meet the energy needs for rapid cell growth and proliferation through metabolic reprogramming, so a comprehensive understanding of pro-tumor and antitumor metabolic switches in TAM is essential to understanding immune escape mechanisms. This paper focuses on the functions of relevant signaling pathways and cytokines during macrophage polarization and metabolic reprogramming, and briefly discusses the effects of different microenvironments and macrophage pathogenicity, in addition to describing the research progress of inhibitory drugs for certain metabolic and polarized signaling pathways.

Crosstalk among m6A RNA methylation, hypoxia and metabolic reprogramming in TME: from immunosuppressive microenvironment to clinical application

The tumor microenvironment (TME), which is regulated by intrinsic oncogenic mechanisms and epigenetic modifications, has become a research hotspot in recent years. Characteristic features of TME include hypoxia, metabolic dysregulation, and immunosuppression. One of the most common RNA modifications, N6-methyladenosine (m⁶A) methylation, is widely involved in the regulation of physiological and pathological processes, including tumor development. Compelling evidence indicates that m⁶A methylation regulates transcription and protein expression through shearing, export, translation, and processing, thereby participating in the dynamic evolution of TME. Specifically, m⁶A methylation-mediated adaptation to hypoxia, metabolic dysregulation, and phenotypic shift of immune cells synergistically promote the formation of an immunosuppressive TME that supports tumor proliferation and metastasis. In this review, we have focused on the involvement of m⁶A methylation in the dynamic evolution of tumor-adaptive TME and described the detailed mechanisms linking m⁶A methylation to change in tumor cell biological functions. In view of the collective data, we advocate treating TME as a complete ecosystem in which components crosstalk with each other to synergistically achieve tumor adaptive changes. Finally, we describe the potential utility of m⁶A methylation-targeted therapies and tumor immunotherapy in clinical applications and the challenges faced, with the aim of advancing m⁶A methylation research.

EBV Infection and Its Regulated Metabolic Reprogramming in Nasopharyngeal Tumorigenesis

Viral oncogenes may drive cellular metabolic reprogramming to modulate the normal epithelia cell malignant transformation. Understanding the viral oncogene–mediated signaling transduction dysregulation that involves in metabolic reprogramming may provide new therapeutic targets for virus-associated cancer treatment. Latent EBV infection and expression of viral oncogenes, including latent membrane proteins 1 and 2 (LMP1/2), and EBV-encoded BamH I-A rightward transcripts (BART) microRNAs (miR-BARTs), have been demonstrated to play fundamental roles in altering host cell metabolism to support nasopharyngeal carcinoma (NPC) pathogenesis. Yet, how do EBV infection and its encoded oncogenes facilitated the metabolic shifting and their roles in NPC carcinogenesis remains unclear. In this review, we will focus on delineating how EBV infection and its encoded oncoproteins altered the metabolic reprograming of infected cells to support their malignances. Furthermore, based on the understanding of the host’s metabolic signaling alterations induced by EBV, we will provide a new perspective on the interplay between EBV infection and these metabolic pathways and offering a potential therapeutic intervention strategy in the treatment of EBV-associated malignant diseases.

Tumor Microenvironment: Lactic Acid Promotes Tumor Development

Lactic acid is a "metabolic waste" product of glycolysis that is produced in the body. However, the role of lactic acid in the development of human malignancies has gained increasing interest lately as a multifunctional small molecule chemical. There is evidence that tumor cells may create a large amount of lactic acid through glycolysis even when they have abundant oxygen. Tumor tissues have a higher quantity of lactic acid than normal tissues. Lactic acid is required for tumor development. Lactate is an immunomodulatory chemical that affects both innate and adaptive immune cells' effector functions. In immune cells, the lactate signaling pathway may potentially serve as a link between metabolism and immunity. Lactate homeostasis is significantly disrupted in the TME. Lactate accumulation results in acidosis, angiogenesis, immunosuppression, and tumor cell proliferation and survival, all of which are deleterious to health. Thus, augmenting anticancer immune responses by lactate metabolism inhibition may modify lactate levels in the tumor microenvironment. This review will evaluate the role of lactic acid in tumor formation, metastasis, prognosis, treatment, and histone modification. Our findings will be of considerable interest to readers, particularly those engaged in the therapeutic treatment of cancer patients. Treatments targeting the inhibition of lactate synthesis and blocking the source of lactate have emerged as a potential new therapeutic option for oncology patients. Additionally, lactic acid levels in the plasma may serve as biomarkers for disease stage and may be beneficial for evaluating therapy effectiveness in individuals with tumors.

Dysregulated Immune and Metabolic Microenvironment Is Associated with the Post-Operative Relapse in Stage I Non-Small Cell Lung Cancer

Simple Summary

The underlying mechanism of post-operative relapse of non-small cell lung cancer (NSCLC) remained poorly understood. This study highlights that both tumors and adjacent tissues from stage I NSCLC with relapse show a dysregulated immune and metabolic environment. Immune response shifts from an active state in primary tumors to a suppressive state in recurrent tumors. A model based on the enriched biological features in the primary tumors with relapse could effectively predict recurrence for stage I NSCLC. These results provide insights into the underpinning of the post-operative relapse and suggest that identifying NSCLC patients with a high risk of relapse could help the clinical decision of applying appropriate therapeutic interventions.

Abstract

The underlying mechanism of post-operative relapse of non-small cell lung cancer (NSCLC) remains poorly understood. We enrolled 57 stage I NSCLC patients with or without relapse and performed whole-exome sequencing (WES) and RNA sequencing (RNA-seq) on available primary and recurrent tumors, as well as on matched tumor-adjacent tissues (TATs). The WES analysis revealed that primary tumors from patients with relapse were enriched with USH2A mutation and 2q31.1 amplification. RNA-seq data showed that the relapse risk was associated with aberrant immune response and metabolism in the microenvironment of primary lesions. TATs from the patients with relapse showed an immunosuppression state. Moreover, recurrent lesions exhibited downregulated immune response compared with their paired primary tumors. Genomic and transcriptomic features were further subjected to build a prediction model classifying patients into groups with different relapse risks. We show that the recurrence risk of stage I NSCLC could be ascribed to the altered immune and metabolic microenvironment. TATs might be affected by cancer cells and facilitate the invasion of tumors. The immune microenvironment in the recurrent lesions is suppressed. Patients with a high risk of relapse need active post-operative intervention.

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

Comparison of metabolic and immunologic responses to transarterial chemoembolization with different chemoembolic regimens in a rabbit VX2 liver tumor model

OBJECTIVES

The goal of this study was to investigate the effects of TACE using Lipiodol, Oncozene™ drug-eluting embolics (DEEs), or LUMI™-DEEs alone, or combined with bicarbonate on the metabolic and immunological tumor microenvironment in a rabbit VX2 tumor model.

METHODS

VX2 liver tumor-bearing rabbits were assigned to five groups. MRI and extracellular pH (pHe) mapping using Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) were performed before and after intra-arterial therapy with conventional TACE (cTACE), DEE-TACE with Idarubicin-eluting Oncozene™-DEEs, or Doxorubicin-eluting LUMI™-DEEs, each with or without prior bicarbonate infusion, and in untreated rabbits or treated with intra-arterial bicarbonate only. Imaging results were validated with immunohistochemistry (IHC) staining of cell viability (PCNA, TUNEL) and immune response (HLA-DR, CD3). Statistical analysis was performed using Mann-Whitney U test.

RESULTS

pHe mapping revealed that combining cTACE with prior bicarbonate infusion significantly increased tumor pHe compared to control (p = 0.0175) and cTACE alone (p = 0.0025). IHC staining revealed peritumoral accumulation of HLA-DR+ antigen-presenting cells and CD3 + T-lymphocytes in controls. cTACE-treated tumors showed reduced immune infiltration, which was restored through combination with bicarbonate. DEE-TACE with Oncozene™-DEEs induced moderate intratumoral and marked peritumoral infiltration, which was slightly reduced with bicarbonate. Addition of bicarbonate prior to LUMI™-beads enhanced peritumoral immune cell infiltration compared to LUMI™-beads alone and resulted in the strongest intratumoral immune cell infiltration across all treated groups.

CONCLUSIONS

The choice of chemoembolic regimen for TACE strongly affects post-treatment TME pHe and the ability of immune cells to accumulate and infiltrate the tumor tissue.

KEY POINTS

• Combining conventional transarterial chemotherapy with prior bicarbonate infusion increases the pHe towards a more physiological value (p = 0.0025). • Peritumoral infiltration and intratumoral accumulation patterns of antigen-presenting cells and T-lymphocytes after transarterial chemotherapy were dependent on the choice of the chemoembolic regimen. • Combination of intra-arterial treatment with Doxorubicin-eluting LUMI™-beads and bicarbonate infusion resulted in the strongest intratumoral presence of immune cells (positivity index of 0.47 for HLADR+-cells and 0.62 for CD3+-cells).

1H-NMR Based Metabolomics Technology Identifies Potential Serum Biomarkers of Colorectal Cancer Lung Metastasis in a Mouse Model

Background

Lung metastasis is a common metastasis site of colorectal cancer which largely reduces the quality of life and survival rates of patients. The discovery of potential novel diagnostic biomarkers is very meaningful for the early diagnosis of colorectal cancer with lung metastasis.

Methods

In the present study, the metabonomic profiling of serum samples of lung metastasis mice was analyzed by ¹H-nuclear magnetic resonance (¹H-NMR). Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to elucidate the distinguishing metabolites between different groups, and all achieved excellent separations, which indicated that metastatic mice could be differentiated from control mice based on the metabolic profiles at serum levels. Furthermore, during lung metastasis of colorectal cancer, metabolic phenotypes changed significantly, and some of metabolites were identified.

Results

Among these metabolites, approximately 15 were closely associated with the lung metastasis process. Pathway enrichment analysis results showed deregulation of metabolic pathways participating in the process of lung metastasis, such as synthesis and degradation of ketone bodies pathway, amino acid metabolism pathway and pyruvate metabolism pathway.

Conclusion

The present study demonstrated the metabolic disturbances of serum samples of mice during the lung metastasis process of colorectal cancer and provides potential diagnostic biomarkers for the disease.

Extracellular matrix in cancer progression and therapy

The tumor ecosystem with heterogeneous cellular compositions and the tumor microenvironment has increasingly become the focus of cancer research in recent years. The extracellular matrix (ECM), the major component of the tumor microenvironment, and its interactions with the tumor cells and stromal cells have also enjoyed tremendously increased attention. Like the other components of the tumor microenvironment, the ECM in solid tumors differs significantly from that in normal organs and tissues. We review recent studies of the complex roles the tumor ECM plays in cancer progression, from tumor initiation, growth to angiogenesis and invasion. We highlight that the biomolecular, biophysical, and mechanochemical interactions between the ECM and cells not only regulate the steps of cancer progression, but also affect the efficacy of systemic cancer treatment. We further discuss the strategies to target and modify the tumor ECM to improve cancer therapy.

Hallmarks of Metabolic Reprogramming and Their Role in Viral Pathogenesis

Metabolic reprogramming is a hallmark of cancer and has proven to be critical in viral infections. Metabolic reprogramming provides the cell with energy and biomass for large-scale biosynthesis. Based on studies of the cellular changes that contribute to metabolic reprogramming, seven main hallmarks can be identified: (1) increased glycolysis and lactic acid, (2) increased glutaminolysis, (3) increased pentose phosphate pathway, (4) mitochondrial changes, (5) increased lipid metabolism, (6) changes in amino acid metabolism, and (7) changes in other biosynthetic and bioenergetic pathways. Viruses depend on metabolic reprogramming to increase biomass to fuel viral genome replication and production of new virions. Viruses take advantage of the non-metabolic effects of metabolic reprogramming, creating an anti-apoptotic environment and evading the immune system. Other non-metabolic effects can negatively affect cellular function. Understanding the role metabolic reprogramming plays in viral pathogenesis may provide better therapeutic targets for antivirals.

Pathophysiological Integration of Metabolic Reprogramming in Breast Cancer

Simple Summary

Tumors exhibit metabolic changes that differentiate them from the normal tissues from which they derive. These metabolic changes favor tumor growth, are primarily induced by cancer cells, and produce metabolic and functional changes in the surrounding stromal cells. There is a close functional connection between the metabolic changes in tumor cells and those that appear in the surrounding stroma. A better understanding of intratumoral metabolic interactions may help identify new vulnerabilities that will facilitate new, more individualized treatment strategies against cancer. We review the metabolic changes described in tumor and stromal cells and their functional changes and then consider, in depth, the metabolic interactions between the cells of the two compartments. Although these changes are generic, we illustrate them mainly with reference to examples in breast cancer.

Abstract

Metabolic changes that facilitate tumor growth are one of the hallmarks of cancer. The triggers of these metabolic changes are located in the tumor parenchymal cells, where oncogenic mutations induce an imperative need to proliferate and cause tumor initiation and progression. Cancer cells undergo significant metabolic reorganization during disease progression that is tailored to their energy demands and fluctuating environmental conditions. Oxidative stress plays an essential role as a trigger under such conditions. These metabolic changes are the consequence of the interaction between tumor cells and stromal myofibroblasts. The metabolic changes in tumor cells include protein anabolism and the synthesis of cell membranes and nucleic acids, which all facilitate cell proliferation. They are linked to catabolism and autophagy in stromal myofibroblasts, causing the release of nutrients for the cells of the tumor parenchyma. Metabolic changes lead to an interstitium deficient in nutrients, such as glucose and amino acids, and acidification by lactic acid. Together with hypoxia, they produce functional changes in other cells of the tumor stroma, such as many immune subpopulations and endothelial cells, which lead to tumor growth. Thus, immune cells favor tissue growth through changes in immunosuppression. This review considers some of the metabolic changes described in breast cancer.

Identification of HCC Subtypes With Different Prognosis and Metabolic Patterns Based on Mitophagy

Background: Mitophagy is correlated with tumor initiation and development of malignancy. However, HCC heterogeneity with reference to mitophagy has yet not been systematically explored.

Materials and Methods: Mitophagy-related, glycolysis-related, and cholesterol biosynthesis-related gene sets were obtained from the Reactome database. Mitophagy-related and metabolism-related subtypes were identified using the ConsensusClusterPlus algorithm. Univariate Cox regression was analysis was performed to identify prognosis-related mitophagy regulators. Principal component analysis (PCA) was used to create composite measures of the prognosis-related mitophagy regulators (mitophagyscore). Individuals with a mitophagyscore higher or lower than the median value were classified in high- or low-risk groups. Kaplan-Meier survival and ROC curve analyses were utilized to evaluate the prognostic value of the mitophagyscore. The nomogram and calibration curves were plotted using the“rms” R package. The package “limma” was used for differential gene expression analysis. Differentially expressed genes (DEGs) between high- and low-risk groups were used as queries in the CMap database. R package “pRRophetic” and Genomics of Drug Sensitivity in Cancer (GDSC) database were used to determine the sensitivity of 21 previously reported anti-HCC drugs.

Results: Three distinct HCC subtypes with different mitophagic accumulation (low, high, and intermediate mitophagy subtypes) were identified. High mitophagy subtype had the worst outcome and highest glycolysis level. The lowest degree of hypoxia and highest cholesterol biosynthesis was observed in the low mitophagy subtype; oncogenic dedifferentiation level in the intermediate mitophagy subtype was the lowest. Mitophagyscore could serve as a novel prognostic indicator for HCC.High-risk patients had a poorer prognosis (log-rank test, p < 0.001). The area under the ROC curve for mitophagyscore in 1-year survival was 0.77 in the TCGA cohort and 0.75 in the ICGC cohort. Nine candidate small molecules which were potential drugs for HCC treatment were identified from the CMap database. A decline in the sensitivity towards 21 anti-HCC drugs was observed in low-risk patients by GDSC database. We also identified a novel key gene, SPP1, which was highly associated with different mitophagic subtypes.

Conclusion: Based on bioinformatic analyses, we systematically examined the HCC heterogeneity with reference to mitophagy and observed three distinct HCC subtypes having different prognoses and metabolic patterns.

Heat shock protein A12A activates migration of hepatocellular carcinoma cells in a monocarboxylate transporter 4-dependent manner

Metastasis is responsible for most of the hepatocellular carcinoma (HCC)-associated death. However, its underlying mechanism has yet to be fully elucidated. Glycolysis-derived lactate has been shown to be a powerful regulator of cancer metastasis. Heat shock protein A12A (HSPA12A) encodes a novel member of HSP70 family. We have recently demonstrated that heat shock protein A12A (HSPA12A) inhibited renal cancer cell migration by suppressing lactate output and glycolytic activity, which were mediated by unstabilizing CD147 and promoting its degradation. By striking contrast, here we demonstrated that HSPA12A promoted migration of human HCC cells. Extracellular acidification, lactate export, and glycolytic activity in HCC cells were also promoted following HSPA12A overexpression. Further analysis revealed that HSPA12A interacted with MCT4 and increased its membrane localization, thereby promoting export of lactate generated from glycolysis; this led, ultimately, to HCC cell migration. Our results revealed the opposite effect of HSPA12A on migration of renal cancer cells and that of HCC cells. Of note, in contrast to the inhibitory effect on CD147 expression in renal cancer cells, we found that HSPA12A increased CD147 expression in HCC cells, indicating that the expression of CD147 might exist heterogeneity in different cancer cell types. Taken together, we identified HSPA12A as an activator of HCC migration, a role opposite to that of renal cancer cells. Inhibiting HSPA12A might be a potential therapeutic intervention for HCC metastasis.

In Vivo Anticancer Activity of AZD3965: A Systematic Review

Proliferating cancer cells have high energy demands, which is mainly obtained through glycolysis. The transmembrane trafficking of lactate, a major metabolite produced by glycolytic cancer cells, relies on monocarboxylate transporters (MCTs). MCT1 optimally imports lactate, although it can work bidirectionally, and its activity has been linked to cancer aggressiveness and poor outcomes. AZD3965, a specific MCT1 inhibitor, was tested both in vitro and in vivo, with encouraging results; a phase I clinical trial has already been undertaken. Thus, analysis of the experimental evidence using AZD3965 in different cancer types could give valuable information for its clinical use. This systematic review aimed to assess the in vivo anticancer activity of AZD3965 either alone (monotherapy) or with other interventions (combination therapy). Study search was performed in nine different databases using the keywords “AZD3965 in vivo” as search terms. The results show that AZD3965 successfully decreased tumor growth and promoted intracellular lactate accumulation, which confirmed its effectiveness, especially in combined therapy. These results support the setup of clinical trials, but other important findings, namely AZD3965 enhanced activity when given in combination with other therapies, or MCT4-induced treatment resistance, should be further considered in the clinical trial design to improve therapy response.

Identification and Development of Subtypes with Poor Prognosis in Gastric Cancer Based on Both Hypoxia and Immune Cell Infiltration

Purpose

Hypoxia and immune cell infiltration play an important role in the progression and metastasis of gastric cancer. However, the molecular classification of gastric cancer combined with hypoxia and immune cell infiltration remains unknown.

Materials and Methods

ssGSEA was used to evaluate the hypoxic state and immune cell infiltration of 1059 gastric cancer samples collected from the GEO and TCGA database. Based on the results, unsupervised clustering was performed to obtain different gastric cancer subtypes. The differentially expressed genes related to OS between these subtypes were utilized for LASSO analysis to construct a prognostic signature (HIscore). Subsequently, small-molecule drugs were predicted using the Connectivity Map (CMAP) database.

Results

We obtained three hypoxic-immune infiltration patterns (HIcluster A-C) with different prognoses and classified them as low hypoxic/low immune, high hypoxic/high immune, and low hypoxic/high immune subtypes. Based on the differential genes between HIclusters, we have also obtained other three gastric cancer subtypes (genecluster A-C) and a 13-gene signature (HIscore). At the same time, we extensively explored the clinical and transcriptome traits in different clusters and groups with high or low HIscore. We proved that HIscore is an independent prognostic biomarker and an indicator of genome stability and EMT. Using the CMAP database, we found 96 small-molecule drugs that could reverse the poor prognosis and could serve as therapeutic drugs, especially for gastric cancer patients with high HIscore.

Conclusion

Our study evaluated the hypoxic state and immune cell infiltration in gastric tumors, and identified different gastric cancer subtypes. In addition, we established a hypoxia-immune signature to predict prognosis which is tightly linked to tumor EMT and genomic stability. Based on HIscore, we used the CMAP database to explore small-molecule drugs that may have the potential in serving as therapeutic drugs.

Tumor Lymphatic Interactions Induce CXCR2-CXCL5 Axis and Alter Cellular Metabolism and Lymphangiogenic Pathways to Promote Cholangiocarcinoma

Cholangiocarcinoma (CCA), or cancer of bile duct epithelial cells, is a very aggressive malignancy characterized by early lymphangiogenesis in the tumor microenvironment (TME) and lymph node (LN) metastasis which correlate with adverse patient outcome. However, the specific roles of lymphatic endothelial cells (LECs) that promote LN metastasis remains unexplored. Here we aimed to identify the dynamic molecular crosstalk between LECs and CCA cells that activate tumor-promoting pathways and enhances lymphangiogenic mechanisms. Our studies show that inflamed LECs produced high levels of chemokine CXCL5 that signals through its receptor CXCR2 on CCA cells. The CXCR2-CXCL5 signaling axis in turn activates EMT (epithelial-mesenchymal transition) inducing MMP (matrix metalloproteinase) genes such as GLI, PTCHD, and MMP2 in CCA cells that promote CCA migration and invasion. Further, rate of mitochondrial respiration and glycolysis of CCA cells was significantly upregulated by inflamed LECs and CXCL5 activation, indicating metabolic reprogramming. CXCL5 also induced lactate production, glucose uptake, and mitoROS. CXCL5 also induced LEC tube formation and increased metabolic gene expression in LECs. In vivo studies using CCA orthotopic models confirmed several of these mechanisms. Our data points to a key finding that LECs upregulate critical tumor-promoting pathways in CCA via CXCR2-CXCL5 axis, which further augments CCA metastasis.

Lactate Is a Metabolic Mediator That Shapes Immune Cell Fate and Function

Lactate and the associated H⁺ ions are still introduced in many biochemistry and general biology textbooks and courses as a metabolic by-product within fast or oxygen-independent glycolysis. However, the role of lactate as a fuel source has been well-appreciated in the field of physiology, and the role of lactate as a metabolic feedback regulator and distinct signaling molecule is beginning to gain traction in the field of immunology. We now know that while lactate and the associated H⁺ ions are generally immunosuppressive negative regulators, there are cell, receptor, mediator, and microenvironment-specific effects that augment T helper (Th)17, macrophage (M)2, tumor-associated macrophage, and neutrophil functions. Moreover, we are beginning to uncover how lactate and H⁺ utilize different transporters and signaling cascades in various immune cell types. These immunomodulatory effects may have a substantial impact in cancer, sepsis, autoimmunity, wound healing, and other immunomodulatory conditions with elevated lactate levels. In this article, we summarize the known effects of lactate and H⁺ on immune cells to hypothesize potential explanations for the divergent inflammatory vs. anti-inflammatory effects.

Bisphenol A Alters the Energy Metabolism of Stromal Cells and Could Promote Bladder Cancer Progression

Simple Summary

Our research brings new insight on the potential impact of bisphenol A on bladder cancer progression. By evaluating the effects of bisphenol A on the stromal environment of bladder cancer, we aimed to demonstrate that this endocrine disruptor could promote bladder cancer invasion through alteration of the energy metabolism of stromal cells, specifically on bladder fibroblasts and cancer-associated fibroblasts. These findings could modify the understanding of bladder cancer since bladder tissue is not recognized as a hormone-sensitive tissue. Consequently, our study suggests that endocrine disruptors, such as bisphenol A, could impact bladder cancer progression.

Abstract

Bisphenol A (BPA) is an endocrine-disrupting molecule used in plastics. Through its release in food and the environment, BPA can be found in humans and is mostly excreted in urine. The bladder is therefore continuously exposed to this compound. BPA can bind to multiple cell receptors involved in proliferation, migration and invasion pathways, and exposure to BPA is associated with cancer progression. Considering the physiological concentrations of BPA in urine, we tested the effect of nanomolar concentrations of BPA on the metabolism of bladder fibroblasts and cancer-associated fibroblasts (CAFs). Our results show that BPA led to a decreased metabolism in fibroblasts, which could alter the extracellular matrix. Furthermore, CAF induction triggered a metabolic switch, similar to the Warburg effect described in cancer cells. Additionally, we demonstrated that nanomolar concentrations of BPA could exacerbate this metabolic switch observed in CAFs via an increased glycolytic metabolism, leading to greater acidification of the extracellular environment. These findings suggest that chronic exposure to BPA could promote cancer progression through an alteration of the metabolism of stromal cells.

The Dog as a Model to Study the Tumor Microenvironment

Cancer is a complex and dynamic disease with an outcome that depends on a strict crosstalk between tumor cells and other components in tumor microenvironment, namely, tumor-infiltrating immune cells, fibroblasts, cancer stem cells, adipocytes, and endothelial cells. Within the tumor microenvironment, macrophages and T-lymphocytes appear to be key effectors during the several steps of tumor initiation and progression. Tumor cells, through the release of a plethora of signaling molecules, can induce immune tolerance, by avoiding immune surveillance, and inhibit immune cells cytotoxic functions. Furthermore, as the tumor grows, tumor microenvironment reveals a series of dysfunctional conditions that potentiate a polarization of harmful humoral Th2 and Th17, an upregulation of Treg cells, and a differentiation of macrophages into the M2 subtype, which contribute to the activation of several signaling pathways involving important tissue biomarkers (COX-2, EGFR, VEGF) implicated in cancer aggressiveness and poor clinical outcomes. In order to maintain the tumor growth, cancer cells acquire several adaptations such as neovascularization and metabolic reprogramming. An extensive intracellular production of lactate and protons is observed in tumor cells as a result of their high glycolytic metabolism. This contributes not only for the microenvironment pH alteration but also to shape the immune response that ultimately impairs immune cells capabilities and effector functions.In this chapter, the complexity of tumor microenvironment, with special focus on macrophages, T-lymphocytes, and the impact of lactate efflux, was reviewed, always trying to demonstrate the strong similarities between data from studies of humans and dogs, a widely proposed model for comparative oncology studies.

Metabolic Reprogramming and Immune Evasion in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumor of the nasopharynx mainly characterized by geographic distribution and EBV infection. Metabolic reprogramming, one of the cancer hallmarks, has been frequently reported in NPCs to adapt to internal energy demands and external environmental pressures. Inevitably, the metabolic reprogramming within the tumor cell will lead to a decreased pH value and diverse nutritional supplements in the tumor-infiltrating micro-environment incorporating immune cells, fibroblasts, and endothelial cells. Accumulated evidence indicates that metabolic reprogramming derived from NPC cells may facilitate cancer progression and immunosuppression by cell-cell communications with their surrounding immune cells. This review presents the dysregulated metabolism processes, including glucose, fatty acid, amino acid, nucleotide metabolism, and their mutual interactions in NPC. Moreover, the potential connections between reprogrammed metabolism, tumor immunity, and associated therapy would be discussed in this review. Accordingly, the development of targets on the interactions between metabolic reprogramming and immune cells may provide assistances to overcome the current treatment resistance in NPC patients.

Harnessing Metabolic Reprogramming to Improve Cancer Immunotherapy

Immune escape is one of the hallmarks of cancer. While metabolic reprogramming provides survival advantage to tumor cancer cells, accumulating data also suggest such metabolic rewiring directly affects the activation, differentiation and function of immune cells, particularly in the tumor microenvironment. Understanding how metabolic reprogramming affects both tumor and immune cells, as well as their interplay, is therefore critical to better modulate tumor immune microenvironment in the era of cancer immunotherapy. In this review, we discuss alterations in several essential metabolic pathways in both tumor and key immune cells, provide evidence on their dynamic interaction, and propose innovative strategies to improve cancer immunotherapy via the modulation of metabolic pathways.

Lactate cross-talk in host-pathogen interactions

Lactate is the main product generated at the end of anaerobic glycolysis or during the Warburg effect and its role as an active signalling molecule is increasingly recognised. Lactate can be released and used by host cells, by pathogens and commensal organisms, thus being essential for the homeostasis of host-microbe interactions. Infection can alter this intricate balance, and the presence of lactate transporters in most human cells including immune cells, as well as in a variety of pathogens (including bacteria, fungi and complex parasites) demonstrates the importance of this metabolite in regulating host-pathogen interactions. This review will cover lactate secretion and sensing in humans and microbes, and will discuss the existing evidence supporting a role for lactate in pathogen growth and persistence, together with lactate's ability to impact the orchestration of effective immune responses. The ubiquitous presence of lactate in the context of infection and the ability of both host cells and pathogens to sense and respond to it, makes manipulation of lactate a potential novel therapeutic strategy. Here, we will discuss the preliminary research that has been carried out in the context of cancer, autoimmunity and inflammation.

3D Cancer Models: Depicting Cellular Crosstalk within the Tumour Microenvironment

The tumour microenvironment plays a critical role in tumour progression and drug resistance processes. Non-malignant cell players, such as fibroblasts, endothelial cells, immune cells and others, interact with each other and with the tumour cells, shaping the disease. Though the role of each cell type and cell communication mechanisms have been progressively studied, the complexity of this cellular network and its role in disease mechanism and therapeutic response are still being unveiled. Animal models have been mainly used, as they can represent systemic interactions and conditions, though they face recognized limitations in translational potential due to interspecies differences. In vitro 3D cancer models can surpass these limitations, by incorporating human cells, including patient-derived ones, and allowing a range of experimental designs with precise control of each tumour microenvironment element. We summarize the role of each tumour microenvironment component and review studies proposing 3D co-culture strategies of tumour cells and non-malignant cell components. Moreover, we discuss the potential of these modelling approaches to uncover potential therapeutic targets in the tumour microenvironment and assess therapeutic efficacy, current bottlenecks and perspectives.

More Than Meets the Eye Regarding Cancer Metabolism

In spite of the continuous improvement in our knowledge of the nature of cancer, the causes of its formation and the development of new treatment methods, our knowledge is still incomplete. A key issue is the difference in metabolism between normal and cancer cells. The features that distinguish cancer cells from normal cells are the increased proliferation and abnormal differentiation and maturation of these cells, which are due to regulatory changes in the emerging tumour. Normal cells use oxidative phosphorylation (OXPHOS) in the mitochondrion as a major source of energy during division. During OXPHOS, there are 36 ATP molecules produced from one molecule of glucose, in contrast to glycolysis which provides an ATP supply of only two molecules. Although aerobic glucose metabolism is more efficient, metabolism based on intensive glycolysis provides intermediate metabolites necessary for the synthesis of nucleic acids, proteins and lipids, which are in constant high demand due to the intense cell division in cancer. This is the main reason why the cancer cell does not "give up" on glycolysis despite the high demand for energy in the form of ATP. One of the evolving trends in the development of anti-cancer therapies is to exploit differences in the metabolism of normal cells and cancer cells. Currently constructed therapies, based on cell metabolism, focus on the attempt to reprogram the metabolic pathways of the cell in such a manner that it becomes possible to stop unrestrained proliferation.