Lactate Dehydrogenases as Metabolic Links between Tumor and Stroma in the Tumor Microenvironment

Downregulated expression of lactate dehydrogenase in adult oligodendrocytes and its implication for the transfer of glycolysis products to axons

Oligodendrocytes and astrocytes are metabolically coupled to neuronal compartments. Pyruvate and lactate can shuttle between glial cells and axons via monocarboxylate transporters. However, lactate can only be synthesized or used in metabolic reactions with the help of lactate dehydrogenase (LDH), a tetramer of LDHA and LDHB subunits in varying compositions. Here we show that mice with a cell type-specific disruption of both Ldha and Ldhb genes in oligodendrocytes lack a pathological phenotype that would be indicative of oligodendroglial dysfunctions or lack of axonal metabolic support. Indeed, when combining immunohistochemical, electron microscopical, and in situ hybridization analyses in adult mice, we found that the vast majority of mature oligodendrocytes lack detectable expression of LDH. Even in neurodegenerative disease models and in mice under metabolic stress LDH was not increased. In contrast, at early development and in the remyelinating brain, LDHA was readily detectable in immature oligodendrocytes. Interestingly, by immunoelectron microscopy LDHA was particularly enriched at gap junctions formed between adjacent astrocytes and at junctions between astrocytes and oligodendrocytes. Our data suggest that oligodendrocytes metabolize lactate during development and remyelination. In contrast, for metabolic support of axons mature oligodendrocytes may export their own glycolysis products as pyruvate rather than lactate. Lacking LDH, these oligodendrocytes can also "funnel" lactate through their "myelinic" channels between gap junction-coupled astrocytes and axons without metabolizing it. We suggest a working model, in which the unequal cellular distribution of LDH in white matter tracts facilitates a rapid and efficient transport of glycolysis products among glial and axonal compartments.

Variation of peripheral blood-based biomarkers for response of anti-PD-1 immunotherapy in non-small-cell lung cancer

PURPOSE

Immune checkpoint inhibitors (ICIs) for non-small-cell lung cancer (NSCLC) are on the rise, but unfortunately, only a small percentage of patients benefit from them in the long term. Thus, it is crucial to identify biomarkers that can forecast the efficacy of immunotherapy.

METHODS

We retrospectively studied 224 patients with NSCLC who underwent anti-PD-1 therapy. The role of biomarkers and clinical characteristics were assessed in a prognostic model.

RESULTS

Only 14.3% of patients had both programmed death ligand 1 (PD-L1) and tumor mutational burden (TMB) outcomes, highlighting the need to investigate more available biomarkers. Our analysis found a correlation between histological PD-L1 TPS and hematological PD-1 expression. Analysis of hematological biomarkers revealed that elevated expression of CD4/CD8 and LYM% are positively associated with effective immunotherapy, while PD-1+ on T cells, NLR, and MLR have a negative impact. Moreover, high level of ΔCEA%, CYFRA21-1 and LDH may suggest ineffective ICIs. We also observed that disparate immunotherapy drugs didn't significantly impact prognosis. Lastly, by comparing squamous carcinoma and adenocarcinoma cohorts, ΔCEA%, CD3+PD-1+, CD4+PD-1+, and CD4/CD8 are more important in predicting the prognosis of adenocarcinoma patients, while age is more significant for squamous carcinoma patients.

CONCLUSION

Our research has yielded encouraging results in identifying a correlation between immunotherapy's response and clinical characteristics, peripheral immune cell subsets, and biochemical and immunological biomarkers. The screened hematological detection panel could be used to forecast an NSCLC patient's response to anti-PD-1 immunotherapy with an accuracy rate of 76.3%, which could help customize suitable therapeutic decision-making.

Single-cell sequencing and multiple machine learning algorithms to identify key T-cell differentiation gene for progression of NAFLD cirrhosis to hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC), which is closely associated with chronicinflammation, is the most common liver cancer and primarily involves dysregulated immune responses in the precancerous microenvironment. Currently, most studies have been limited to HCC incidence. However, the immunopathogenic mechanisms underlying precancerous lesions remain unknown. Methods: We obtained single-cell sequencing data (GSE136103) from two nonalcoholic fatty liver disease (NAFLD) cirrhosis samples and five healthy samples. Using pseudo-time analysis, we systematically identified five different T-cell differentiation states. Ten machine-learning algorithms were used in 81 combinations to integrate the frameworks and establish the best T-cell differentiation-related prognostic signature in a multi-cohort bulk transcriptome analysis. Results: LDHA was considered a core gene, and the results were validated using multiple external datasets. In addition, we validated LDHA expression using immunohistochemistry and flow cytometry. Conclusion: LDHA is a crucial marker gene in T cells for the progression of NAFLD cirrhosis to HCC.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Metabolic Rewiring in Cancer: Small Molecule Inhibitors in Colorectal Cancer Therapy

Alterations in cellular metabolism, such as dysregulation in glycolysis, lipid metabolism, and glutaminolysis in response to hypoxic and low-nutrient conditions within the tumor microenvironment, are well-recognized hallmarks of cancer. Therefore, understanding the interplay between aerobic glycolysis, lipid metabolism, and glutaminolysis is crucial for developing effective metabolism-based therapies for cancer, particularly in the context of colorectal cancer (CRC). In this regard, the present review explores the complex field of metabolic reprogramming in tumorigenesis and progression, providing insights into the current landscape of small molecule inhibitors targeting tumorigenic metabolic pathways and their implications for CRC treatment.

Back to the basics-risk factor identification of pediatric malignant lymphadenopathy proven by pathological studies

PURPOSE

Lymphadenopathy (LAP) is a common problem in the pediatric patient. History, physical examinations (PE), ultrasounds, and blood tests were often obtained while studying such lesions. Malignancy should be highly suspected in certain conditions. This study evaluates the relationship between malignant LAP and risk factors for pediatric patients.

MATERIALS AND METHODS

Medical records of matched patients are reviewed, and data are retrospectively collected. History, PE findings, laboratory data, ultrasound findings, and pathological findings were recorded and analyzed. The median values (interquartile range, IQR) were expressed for continuous variables, and the number of patients (percentage) for categorical variables. Comparisons between groups were performed using the Mann-Whitney U test and the chi-squared test. The significance was set as p value < 0.05.

RESULTS

A total of 142 pediatric patients underwent a biopsy in our department for LAP from July 2004 to August 2021. Among them, 108 (76.1 %) patients had benign lesions, and 34 (23.9 %) had malignancies. Weight loss, fixed LAP, firm consistency, and serum lactate dehydrogenase (LDH) exceeding 240 U/L were more related to malignant LAP than other risk factors. Multiple regression analysis revealed two independent risk factors. The receiver operating characteristic curve regarding LDH level predicting malignancy revealed a sensitivity of 79.31 % and specificity of 36.51 % by applying the criterion as 230 U/L.

CONCLUSIONS

For pediatric LAP, history-taking and physical examinations remained the most important approaches. Ultrasounds, serum LDH, and other laboratory studies may only provide clues. The cutoff level of LDH revealed low sensitivity and specificity for malignant LAP. With firm LAP, which is fixed, a biopsy for tissue proof should be performed.

Regulation of Hypoxia Dependent Reprogramming of Cancer Metabolism: Role of HIF-1 and Its Potential Therapeutic Implications in Leukemia

Metabolic reprogramming occurs to meet cancer cells' high energy demand. Its function is essential to the survival of malignancies. Comparing cancer cells to non-malignant cells has revealed that cancer cells have altered metabolism. Several pathways, particularly mTOR, Akt, PI3K, and HIF-1 (hypoxia-inducible factor-1) modulate the metabolism of cancer. Among other aspects of cancer biology, gene expression in metabolism, survival, invasion, proliferation, and angiogenesis of cells are controlled by HIF-1, a vital controller of cellular responsiveness to hypoxia. This article examines various cancer cell metabolisms, metabolic alterations that can take place in cancer cells, metabolic pathways, and molecular aspects of metabolic alteration in cancer cells placing special attention on the consequences of hypoxia-inducible factor and summarising some of their novel targets in the treatment of cancer including leukemia. A brief description of HIF-1α's role and target in a few common types of hematological malignancies (leukemia) is also elucidated in the present article.

Decreased LDHB expression in breast tumor cells causes NK cell activation and promotes tumor progression

OBJECTIVE

Abnormal metabolism is the underlying reason for breast cancer progression. Decreased lactate dehydrogenase B (LDHB) has been detected in breast cancer but the function of LDHB remains unknown.

METHODS

Western blot was used to analyze LDHB expression in breast cancer cells. The impact of LDHB on tumor cell migration and invasion was determined using Transwell assays, wound healing assays, and a mouse lung metastasis model. Subcutaneous tumor formation, a natural killer (NK) cell cytotoxicity assay, and flow cytometry evaluated NK cell activation. Immunofluorescence and quantitative real-time PCR detected NK cell activation markers. Kaplan-Meier analysis evaluated the effect of immune cell infiltration on prognosis. Single-sample gene set enrichment analysis determined NK cell activation scores. A support vector machine predicted the role of LDHB in NK cell activation.

RESULTS

In this study we showed that LDHB inhibits the breast cancer cell metastasis and orchestrates metabolic reprogramming within tumor cells. Our results revealed that LDHB-mediated lactic acid clearance in breast cancer cells triggers NK cell activation within the tumor microenvironment. Our findings, which were confirmed in a murine model, demonstrated that LDHB in tumor cells promotes NK cell activation and ultimately results in the eradication of malignant cells. Clinically, our study further validated that LDHB affects immune cell infiltration and function. Specifically, its expression has been linked to enhanced NK cell-mediated cytotoxicity and improved patient survival. Furthermore, we identified LDHB expression in tumors as an important predictor of NK cell activation, with strong predictive ability in some cancers.

CONCLUSIONS

Our results suggest that LDHB is a promising target for activating the tumor immune microenvironment in breast cancer, where LDHB-associated lactic acid clearance leads to increased NK cell activity. This study highlights the critical role of LDHB in regulating immune responses and its potential as a therapeutic target for breast cancer.

Advances in metabolic reprogramming of NK cells in the tumor microenvironment on the impact of NK therapy

Natural killer (NK) cells are unique from other immune cells in that they can rapidly kill multiple neighboring cells without the need for antigenic pre-sensitization once the cells display surface markers associated with oncogenic transformation. Given the dynamic role of NK cells in tumor surveillance, NK cell-based immunotherapy is rapidly becoming a "new force" in tumor immunotherapy. However, challenges remain in the use of NK cell immunotherapy in the treatment of solid tumors. Many metabolic features of the tumor microenvironment (TME) of solid tumors, including oxygen and nutrient (e.g., glucose, amino acids) deprivation, accumulation of specific metabolites (e.g., lactate, adenosine), and limited availability of signaling molecules that allow for metabolic reorganization, multifactorial shaping of the immune-suppressing TME impairs tumor-infiltrating NK cell function. This becomes a key barrier limiting the success of NK cell immunotherapy in solid tumors. Restoration of endogenous NK cells in the TME or overt transfer of functionally improved NK cells holds great promise in cancer therapy. In this paper, we summarize the metabolic biology of NK cells, discuss the effects of TME on NK cell metabolism and effector functions, and review emerging strategies for targeting metabolism-improved NK cell immunotherapy in the TME to circumvent these barriers to achieve superior efficacy of NK cell immunotherapy.

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.

Circ_MAPK9 promotes STAT3 and LDHA expression by silencing miR-642b-3p and affects the progression of hepatocellular carcinoma

BACKGROUND

Aberrant expression and activation of circular RNAs (circRNAs) are closely associated with various cancers. The role of circ_MAPK9 (hsa_circ_0001566) in cancer progression remains unknown. This study aims to investigate the function, mechanism and clinical significance of circ_MAPK9 in hepatocellular carcinoma (HCC).

METHODS

Circ_MAPK9 expression on the microarray of tumor from clinical HCC patients was detected by in situ hybridization (ISH). Circ_MAPK9 knockdown was achieved with siRNAs in SMMC-7721 and SK-Hep1 HCC cell lines. The biological function of circ_MAPK9 was verified in vitro by CCK8 test, colony formation assay, transwell assay, PI-Annexin V staining, and in vivo by xenograft tumor in nude mice. Fluorescent in situ hybridization (FISH), subcellular fractionation assay, a dual-luciferase reporter assay and rescue experiments were employed for further mechanistic investigation.

RESULTS

The expression of circ_MAPK9 was significantly up-regulated in HCC tissues and cells, which was found to be associated with poor prognosis. Patients with high expression of circ_MAPK9 had a shorter overall survival and disease-free survival in comparison to those with low circ_MAPK9 expression. Functional assays showed that circ_MAPK9 knockdown suppressed cellular proliferation, migration, invasion and tumor growth in vivo, and promoted apoptosis in HCC cells. Moreover, we found that circ_MAPK9 knockdown could inhibit aerobic glycolysis by decreasing the production of adenosine triphosphate (ATP) and lactic acid, which was mediated by lactate dehydrogenase (LDHA). Mechanistically, circ_MAPK9 functioned as ceRNA via sponging miR-642b-3p and alleviated the inhibitory effect of miR-642b-3p on its target signal transducer and activator of transcription 3 (STAT3) and LDHA, thereby leading to STAT3 activation and LDHA expression.

CONCLUSIONS

Circ_MAPK9, as an oncogene, promotes HCC growth and metastasis through miR-642b-3p/STAT3-LDHA axis. Circ_MAPK9 could serve as a potential biomarker for HCC poor prognosis and diagnosis.

Oncogenic Alterations of Metabolism Associated with Resistance to Chemotherapy

Metabolic reprogramming in cancer cells is a strategy to meet high proliferation rates, invasion, and metastasis. Also, several researchers indicated that the cellular metabolism changed during the resistance to chemotherapy. Since glycolytic enzymes play a prominent role in these alterations, the ability to reduce resistance to chemotherapy drugs is promising for cancer patients. Oscillating gene expression of these enzymes was involved in the proliferation, invasion, and metastasis of cancer cells. This review discussed the roles of some glycolytic enzymes associated with cancer progression and resistance to chemotherapy in the various cancer types.

Aerobic glycolysis is the predominant means of glucose metabolism in neuronal somata, which protects against oxidative damage

It is generally thought that under basal conditions, neurons produce ATP mainly through mitochondrial oxidative phosphorylation (OXPHOS), and glycolytic activity only predominates when neurons are activated and need to meet higher energy demands. However, it remains unknown whether there are differences in glucose metabolism between neuronal somata and axon terminals. Here, we demonstrated that neuronal somata perform higher levels of aerobic glycolysis and lower levels of OXPHOS than terminals, both during basal and activated states. We found that the glycolytic enzyme pyruvate kinase 2 (PKM2) is localized predominantly in the somata rather than in the terminals. Deletion of Pkm2 in mice results in a switch from aerobic glycolysis to OXPHOS in neuronal somata, leading to oxidative damage and progressive loss of dopaminergic neurons. Our findings update the conventional view that neurons uniformly use OXPHOS under basal conditions and highlight the important role of somatic aerobic glycolysis in maintaining antioxidant capacity.

A machine learning one-class logistic regression model to predict stemness for single cell transcriptomics and spatial omics

Cell annotation is a crucial methodological component to interpreting single cell and spatial omics data. These approaches were developed for single cell analysis but are often biased, manually curated and yet unproven in spatial omics. Here we apply a stemness model for assessing oncogenic states to single cell and spatial omic cancer datasets. This one-class logistic regression machine learning algorithm is used to extract transcriptomic features from non-transformed stem cells to identify dedifferentiated cell states in tumors. We found this method identifies single cell states in metastatic tumor cell populations without the requirement of cell annotation. This machine learning model identified stem-like cell populations not identified in single cell or spatial transcriptomic analysis using existing methods. For the first time, we demonstrate the application of a ML tool across five emerging spatial transcriptomic and proteomic technologies to identify oncogenic stem-like cell types in the tumor microenvironment.

Preparation of a Mesoporous Biosensor for Human Lactate Dehydrogenase for Potential Anticancer Inhibitor Screening

Cancer is the second leading cause of death worldwide, with a dramatic impact due to the acquired resistance of cancers to used chemotherapeutic drugs and treatments. The enzyme lactate dehydrogenase (LDH-A) is responsible for cancer cell proliferation. Recently the development of selective LDH-A inhibitors as drugs for cancer treatment has been reported to be an efficient strategy aiming to decrease cancer cell proliferation and increase the sensitivity to traditional chemotherapeutics. This study aims to obtain a stable and active biocatalyst that can be utilized for such drug screening purposes. It is conceived by adopting human LDH-A enzyme (hLDH-A) and investigating different immobilization techniques on porous supports to achieve a stable and reproducible biosensor for anticancer drugs. The hLDH-A enzyme is covalently immobilized on mesoporous silica (MCM-41) functionalized with amino and aldehyde groups following two different methods. The mesoporous support is characterized by complementary techniques to evaluate the surface chemistry and the porous structure. Fluorescence microscopy analysis confirms the presence of the enzyme on the support surface. The tested immobilizations achieve yields of ≥80%, and the best retained activity of the enzyme is as high as 24.2%. The optimal pH and temperature of the best immobilized hLDH-A are pH 5 and 45 °C for the reduction of pyruvate into lactate, while those for the free enzyme are pH 8 and 45 °C. The stability test carried out at 45 °C on the immobilized enzyme shows a residual activity close to 40% for an extended time. The inhibition caused by NHI-2 is similar for free and immobilized hLDH-A, 48% and 47%, respectively. These findings are significant for those interested in immobilizing enzymes through covalent attachment on inorganic porous supports and pave the way to develop stable and active biocatalyst-based sensors for drug screenings that are useful to propose drug-based cancer treatments.

Antitumor Effects of PRMT5 Inhibition in Sarcomas

Patients with advanced soft-tissue sarcomas (STS) have few therapeutic options. Protein arginine methyltransferase 5 (PRMT5), an anticancer target, has been extensively investigated in recent years in epithelial tumors. To date, no data related to the biological role of PRMT5 inhibition and its potential effect as a treatment in STS have been reported.To investigate the therapeutic potential of PRMT5 targeting in STS, we first evaluated the prognostic value of PRMT5 expression in two different cohorts of patients with STS. We then used the potent and selective GSK3326595 (GSK595) compound to investigate the antitumor effect of the pharmacologic inhibition of PRMT5 in vitro via MTT, apoptosis, cell cycle, clonogenicity, and proliferation assays. In vivo studies were performed with two animal models to evaluate the effects of GSK595 on tumor growth. The mechanisms of action were investigated by RNA sequencing, metabolic pathway analysis, Western blotting, and glucose uptake/lactate production assays.High PRMT5 gene expression levels were significantly associated with worsened metastasis-free survival of patients with STS. GSK595 decreased the global symmetric dimethylarginine level, the proliferation rate and clonogenicity of STS cell lines in vitro and tumor growth in vivo. Moreover, PRMT5 inhibition regulated aerobic glycolysis through downregulation of key enzymes of glycolysis as well as glucose uptake and lactate production.The current study demonstrated that PRMT5 regulates STS cell metabolism and thus represents a potential therapeutic target for STS. Additional studies in diverse sarcoma subtypes will be essential to confirm and expand upon these findings.

SIGNIFICANCE

STSs have limited therapeutic options. We show here the poor prognostic value of high PRMT5 expression in STS. Moreover, we demonstrate that the pharmacologic inhibition of PRMT5 has significant antitumor activity through the downregulation of glycolysis. Our findings support the clinical investigation of PRMT5 inhibition in STSs.

Exploring the possibility of drug repurposing for cancer therapy targeting human lactate dehydrogenase A: a computational approach

Human lactate dehydrogenase A (LDHA) is an anaerobic glycolytic enzyme involved in the inter-conversion of pyruvate to lactate. The level of LDHA in various types of cancer cells is found to be elevated and the dependence of cancer cells on anaerobic glycolysis is viewed as the reason for this elevation. Moreover, inhibition of LDHA activity has been shown to be effective in impairing the growth of tumors, making the LDHA as a potential target for cancer therapy. In this computational study, we have performed a pharmacophore based screening of approved drugs followed by a molecular docking based screening to find a few potential LDHA inhibitors. Molecular dynamics simulations have also been performed to examine the stability of the LDHA-drug complexes as obtained from the docking study. The result of the study showed that darunavir, moxalactam and eprosartan can bind to the active site of LDHA with high affinity in comparison to two known synthetic inhibitors of LDHA. The results of the molecular dynamics simulation showed that these drugs can bind stably with the enzyme through hydrogen bond and hydrophobic interactions. Hence, it is concluded that darunavir, moxalactam and eprosartan may be considered as potential inhibitors of LDHA and can be used for cancer therapy after proper validation of their effectiveness through in vitro, in vivo and clinical trials.Communicated by Ramaswamy H. Sarma.

The role of endoplasmic reticulum stress in promoting aerobic glycolysis in cancer cells: An overview

Aerobic glycolysis, also known as the Warburg effect, is a metabolic phenomenon frequently observed in cancer cells, characterized by the preferential utilization of glucose through glycolysis, even under normal oxygen conditions. This metabolic shift provides cancer cells with a proliferative advantage and supports their survival and growth. While the Warburg effect has been extensively studied, the underlying mechanisms driving this metabolic adaptation in cancer cells remain incompletely understood. In recent years, emerging evidence has suggested a potential link between endoplasmic reticulum (ER) stress and the promotion of aerobic glycolysis in cancer cells. The ER is a vital organelle involved in protein folding, calcium homeostasis, and lipid synthesis. Various cellular stresses, such as hypoxia, nutrient deprivation, and accumulation of misfolded proteins, can lead to ER stress. In response, cells activate the unfolded protein response (UPR) to restore ER homeostasis. However, prolonged or severe ER stress can activate alternative signaling pathways that modulate cellular metabolism, including the promotion of aerobic glycolysis. This review aims to provide an overview of the current understanding regarding the influence of ER stress on aerobic glycolysis in cancer cells to shed light on the complex interplay between ER stress and metabolic alterations in cancer cells. Understanding the intricate relationship between ER stress and the promotion of aerobic glycolysis in cancer cells may provide valuable insights for developing novel therapeutic strategies targeting metabolic vulnerabilities in cancer.

IFN-γ lowers tumor growth by increasing glycolysis and lactate production in a nitric oxide-dependent manner: implications for cancer immunotherapy

Introduction

Interferon-gamma (IFN-γ), the sole member of the type-II interferon family, is well known to protect the host from infectious diseases as well as mount anti-tumor responses. The amounts of IFN-γ in the tumor microenvironment determine the host responses against tumors; however, several tumors employ evasive strategies by responding to low IFN-γ signaling.

Methods

In this study, the response of various tumor cell lines to IFN-γ was studied in vitro.

Results

IFN-γ-activation increases glycolytic flux and reduces mitochondrial function in a nitric oxide (NO)- and reactive oxygen species (ROS)-dependent manner in the H6 hepatoma tumor cell line. The higher glycolysis further fueled NO and ROS production, indicating a reciprocal regulation. These processes are accompanied by Hypoxia inducing factor (HIF)-1α stabilization and HIF-1α-dependent augmentation of the glycolytic flux. The IFN-γ enhancement of lactate production also occurred in other NO-producing cell lines: RAW 264.7 monocyte/macrophage and Renca renal adenocarcinoma. However, two other tumor cell lines, CT26 colon carcinoma and B16F10 melanoma, did not produce NO and lactate upon IFN-γ-activation. HIF-1α stabilization upon IFN-γ-activation led to lower cell growth of B16F10 but not CT26 cells. Importantly, the IFN-γ-activation of both CT26 and B16F10 cells demonstrated significant cellular growth reduction upon metabolic rewiring by exogenous administration of potassium lactate.

Discussion

Clinical studies have shown the crucial roles of IFN-γ for successful cancer immunotherapies involving checkpoint inhibitors and chimeric antigen receptor T cells. The positive implications of this study on the metabolic modulation of IFN-γ activation on heterogeneous tumor cells are discussed.

NSG1 promotes glycolytic metabolism to enhance Esophageal squamous cell carcinoma EMT process by upregulating TGF-β

As a highly enriched endosomal protein within neuronal cells, NSG1 has been discovered to facilitate the process of epithelial-mesenchymal transition (EMT) in esophageal squamous cell carcinoma (ESCC). However, the precise mechanisms behind this phenomenon have yet to be elucidated. The pivotal role of transforming growth factor-β (TGF-β) in triggering the EMT and its significant contribution towards tumor metabolic reprogramming-responsible for EMT activation-has been robustly established. Nevertheless, the extent of TGF-β involvement in the NSG1-mediated EMT within ESCC and the processes through which metabolic reprogramming participates remain ambiguous. We accessed an array of extensive public genome databases to analyze NSG1 expression in ESCC. Regulation of TGF-β by NSG1 was analyzed by transcriptome sequencing, quantitative Real-Time PCR (qRT-PCR), co-immunoprecipitation (CO-IP), and immunofluorescence (IF). Additionally, cellular functional assays and western blot analyses were conducted to elucidate the effect of NSG1 on TGF-β/Smad signaling pathway, as well as its role in ESCC cell metastasis and proliferation. We validated the influence of the NSG1/TGF-β axis on metabolic reprogramming in ESCC by measuring extracellular acidification, glucose uptake, and lactate production. Our findings identify an oncogenic role for NSG1 in ESCC and show a correlation between high NSG1 expression and poor prognosis in ESCC patients. Additional research indicated TGF-β's involvement in the NSG1-induced EMT process. From a mechanistic perspective, NSG1 upregulates TGF-β, activating the TGF-β/Smad signaling pathway and subsequently fostering the EMT process by inducing cell metabolic reprogramming-evident from elevated glycolysis levels. In conclusion, our study highlights the NSG1/TGF-β axis as a promising therapeutic target for ESCC.

The potential role of reprogrammed glucose metabolism: an emerging actionable codependent target in thyroid cancer

Although the incidence of thyroid cancer is increasing year by year, most patients, especially those with differentiated thyroid cancer, can usually be cured with surgery, radioactive iodine, and thyroid-stimulating hormone suppression. However, treatment options for patients with poorly differentiated thyroid cancers or radioiodine-refractory thyroid cancer have historically been limited. Altered energy metabolism is one of the hallmarks of cancer and a well-documented feature in thyroid cancer. In a hypoxic environment with extreme nutrient deficiencies resulting from uncontrolled growth, thyroid cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. This review summarizes past and recent advances in our understanding of the reprogramming of glucose metabolism in thyroid cancer cells, which we expect will yield new therapeutic approaches for patients with special pathological types of thyroid cancer by targeting reprogrammed glucose metabolism.

The Ratio of Key Metabolic Transcripts Is a Predictive Biomarker of Breast Cancer Metastasis to the Lung

Understanding the rewired metabolism underlying organ-specific metastasis in breast cancer could help identify strategies to improve the treatment and prevention of metastatic disease. Here, we used a systems biology approach to compare metabolic fluxes used by parental breast cancer cells and their brain- and lung-homing derivatives. Divergent lineages had distinct, heritable metabolic fluxes. Lung-homing cells maintained high glycolytic flux despite low levels of glycolytic intermediates, constitutively activating a pathway sink into lactate. This strong Warburg effect was associated with a high ratio of lactate dehydrogenase (LDH) to pyruvate dehydrogenase (PDH) expression, which correlated with lung metastasis in patients with breast cancer. Although feature classification models trained on clinical characteristics alone were unable to predict tropism, the LDH/PDH ratio was a significant predictor of metastasis to the lung but not to other organs, independent of other transcriptomic signatures. High lactate efflux was also a trait in lung-homing metastatic pancreatic cancer cells, suggesting that lactate production may be a convergent phenotype in lung metastasis. Together, these analyses highlight the essential role that metabolism plays in organ-specific cancer metastasis and identify a putative biomarker for predicting lung metastasis in patients with breast cancer.

SIGNIFICANCE

Lung-homing metastatic breast cancer cells express an elevated ratio of lactate dehydrogenase to pyruvate dehydrogenase, indicating that ratios of specific metabolic gene transcripts have potential as metabolic biomarkers for predicting organ-specific metastasis.

Role of exosomes in transferring chemoresistance through modulation of cancer glycolytic cell metabolism

Chemoresistance constitute a major obstacle in cancer treatment, leading to limited options and decreased patient survival. Recent studies have revealed a novel mechanism of chemoresistance acquisition: the transfer of information via exosomes, small vesicles secreted by various cells. Exosomes play a crucial role in intercellular communication by carrying proteins, nucleic acids, and metabolites, influencing cancer cell behavior and response to treatment. One crucial mechanism of resistance is cancer metabolic reprogramming, which involves alterations in the cellular metabolic pathways to support the survival and proliferation of drug-resistant cancer cells. This metabolic reprogramming often includes increased glycolysis, providing cancer cells with the necessary energy and building blocks to evade the effects of chemotherapy. Notably, exosomes have been found to transport glycolytic enzymes, as identified in proteomic profiling, leading to the reprogramming of metabolic pathways, facilitating altered glucose metabolism and increased lactate production. As a result, they profoundly impact the tumor microenvironment, promoting tumor progression, survival, immune evasion, and drug resistance.Understanding the complexities of such exosome-mediated cell-to-cell communication might open new therapeutic avenues and facilitate biomarker development in managing cancers characterized by aggressive glycolytic features. Moreover, given the intricate nature of metabolic abnormalities combining future exosome-based-targeted therapies with existing treatments like chemotherapy, immunotherapy, and targeted therapies holds promise for achieving synergistic effects to overcome resistance and improve cancer treatment outcomes.

Targeting Lactate Dehydrogenase-B as a Strategy to Fight Cancer: Identification of Potential Inhibitors by In Silico Analysis and In Vitro Screening

Lactate dehydrogenase (LDH) is an enzyme that catalyzes the reversible conversion of lactate to pyruvate while reducing NAD+ to NADH (or oxidizing NADH to NAD+). Due to its central role in the Warburg effect, LDH-A isoform has been considered a promising target for treating several types of cancer. However, research on inhibitors targeting LDH-B isoform is still limited, despite the enzyme's implication in the development of specific cancer types such as breast and lung cancer. This study aimed to identify small-molecule compounds that specifically inhibit LDH-B. Our in silico analysis identified eight commercially available compounds that may affect LDH-B activity. The best five candidates, namely tucatinib, capmatinib, moxidectin, rifampicin, and acetyldigoxin, were evaluated further in vitro. Our results revealed that two compounds, viz., tucatinib and capmatinib, currently used for treating breast and lung cancer, respectively, could also act as inhibitors of LDH-B. Both compounds inhibited LDH-B activity through an uncompetitive mechanism, as observed in in vitro experiments. Molecular dynamics studies further support these findings. Together, our results suggest that two known drugs currently being used to treat specific cancer types may have a dual effect and target more than one enzyme that facilitates the development of these types of cancers. Furthermore, the results of this study could be used as a new starting point for identifying more potent and specific LDH-B inhibitors.

Salvianolic acid A diminishes LDHA-driven aerobic glycolysis to restrain myofibroblasts activation and cardiac fibrosis via blocking Akt/GSK-3β/HIF-1α axis

Myofibroblasts activation intensively contributes to cardiac fibrosis with undefined mechanism. Salvianolic acid A (SAA) is a phenolic component derived from Salvia miltiorrhiza with antifibrotic potency. This study aimed to interrogate the inhibitory effects and underlying mechanism of SAA on myofibroblasts activation and cardiac fibrosis. Antifibrotic effects of SAA were evaluated in mouse myocardial infarction (MI) model and in vitro myofibroblasts activation model. Metabolic regulatory effects and mechanism of SAA were determined using bioenergetic analysis and cross-validated by multiple metabolic inhibitors and siRNA or plasmid targeting Ldha. Finally, Akt/GSK-3β-related upstream regulatory mechanisms were investigated by immunoblot, q-PCR, and cross-validated by specific inhibitors. SAA inhibited cardiac fibroblasts-to-myofibroblasts transition, suppressed collage matrix proteins expression, and effectively attenuated MI-induced collagen deposition and cardiac fibrosis. SAA attenuated myofibroblasts activation and cardiac fibrosis by inhibiting LDHA-driven abnormal aerobic glycolysis. Mechanistically, SAA inhibited Akt/GSK-3β axis and downregulated HIF-1α expression by promoting its degradation via a noncanonical route, and therefore restrained HIF-1α-triggered Ldha gene expression. SAA is an effective component for treating cardiac fibrosis by diminishing LDHA-driven glycolysis during myofibroblasts activation. Targeting metabolism of myofibroblasts might occupy a potential therapeutic strategy for cardiac fibrosis.

DISTINCT METABOLIC STATES DIRECT RETINAL PIGMENT EPITHELIUM CELL FATE DECISIONS

During tissue regeneration, proliferation, dedifferentiation, and reprogramming are necessary to restore lost structures. However, it is not fully understood how metabolism intersects with these processes. Chicken embryos can regenerate their retina through retinal pigment epithelium (RPE) reprogramming when treated with fibroblast factor 2 (FGF2). Using transcriptome profiling, we uncovered extensive regulation of gene sets pertaining to proliferation, neurogenesis, and glycolysis throughout RPE-to-neural retina reprogramming. By manipulating cell media composition, we determined that glucose, glutamine, or pyruvate are sufficient to support RPE reprogramming identifying glycolysis as a requisite. Conversely, the induction of oxidative metabolism by activation of pyruvate dehydrogenase induces Epithelial-to-mesenchymal transition (EMT), while simultaneously blocking the activation of neural retina fate. We also identify that EMT is partially driven by an oxidative environment. Our findings provide evidence that metabolism controls RPE cell fate decisions and provide insights into the metabolic state of RPE cells, which are prone to fate changes in regeneration and pathologies, such as proliferative vitreoretinopathy.

The Illustration of Altered Glucose Dependency in Drug-Resistant Cancer Cells

A chemotherapeutic approach is crucial in malignancy management, which is often challenging due to the development of chemoresistance. Over time, chemo-resistant cancer cells rapidly repopulate and metastasize, increasing the recurrence rate in cancer patients. Targeting these destined cancer cells is more troublesome for clinicians, as they share biology and molecular cross-talks with normal cells. However, the recent insights into the metabolic profiles of chemo-resistant cancer cells surprisingly illustrated the activation of distinct pathways compared with chemo-sensitive or primary cancer cells. These distinct metabolic dynamics are vital and contribute to the shift from chemo-sensitivity to chemo-resistance in cancer. This review will discuss the important metabolic alterations in cancer cells that lead to drug resistance.

Role of Lactate in the Regulation of Transcriptional Activity of Breast Cancer-Related Genes and Epithelial-to-Mesenchymal Transition Proteins: A Compassion of MCF7 and MDA-MB-231 Cancer Cell Lines

The Warburg Effect is characterized by accelerated glycolytic metabolism and lactate production and under fully aerobic conditions is a hallmark of cancer cells. Recently, we have demonstrated the role of endogenous, glucose-derived lactate as an oncometabolite which regulates gene expression in the estrogen receptor positive (ER+) MCF7 cell line cultivated in glucose media. Presently, with the addition of a triple negative breast cancer (TNBC) cell line, MDA-MB-231, we further confirm the effect of lactate on gene expression patterns and extend results to include lactate effects on protein expression. As well, we report effects of lactate on the expression of E-cadherin and vimentin, proteins associated with epithelial-to-mesenchymal transition (EMT). Endogenous lactate regulates the expression of multiple genes involved in carcinogenesis. In MCF7 cells, lactate increased the expression of EGFR, VEGF, HIF-1a, KRAS, MIF, mTOR, PIK3CA, TP53, and CDK4 as well as decreased the expression of ATM, BRCA1, BRCA2, E2F1, MET, MYC, and RAF mainly after 48h of exposure. On the other hand, in the MDA-MB-231 cell line, lactate increased the expressions of PIK3CA, VEGF, EGFR, mTOR, HIF-1α, ATM, E2F1, TP53 and decreased the expressions of BRCA1, BRCA2, CDK4, CDK6, MET, MIF, MYC, and RAF after 48h of exposure. In response to endogenous lactate, changes in protein expression of representative genes corroborated changes in mRNA expressions. Finally, lactate exposure decreased E-cadherin protein expression in MCF7 cells and increased vimentin expression in MDA-MB-231 cells. Furthermore, by genetically silencing LDHA in MCF7 cells, we show suppression of protein expression of EGFR and HIF-1α, while full protein expression occurred under glucose and glucose + exogenous lactate exposure. Hence, endogenous, glucose-derived lactate, and not glucose, elicited changes in gene and protein expression levels. In this study, we demonstrate that endogenous lactate produced under aerobic conditions (Warburg Effect) elicits important changes in gene and protein expression in both ER+ and TNBC cell lines. The widespread regulation of multiple genes by lactate and involves those involved in carcinogenesis including DNA repair, cell growth, proliferation, angiogenesis, and metastasis. Furthermore, lactate affected the expression of two relevant EMT biomarkers, E-cadherin and vimentin, which could contribute to the complex process of EMT and a shift towards a more mesenchymal phenotype in the two cancer cell lines studied.

Knockdown of PGC1α suppresses dysplastic oral keratinocytes proliferation through reprogramming energy metabolism

Oral potentially malignant disorders (OPMDs) are precursors of oral squamous cell carcinoma (OSCC). Deregulated cellular energy metabolism is a critical hallmark of cancer cells. Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α) plays vital role in mitochondrial energy metabolism. However, the molecular mechanism of PGC1α on OPMDs progression is less unclear. Therefore, we investigated the effects of knockdown PGC1α on human dysplastic oral keratinocytes (DOKs) comprehensively, including cell proliferation, cell cycle, apoptosis, xenograft tumor, mitochondrial DNA (mtDNA), mitochondrial electron transport chain complexes (ETC), reactive oxygen species (ROS), oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and glucose uptake. We found that knockdown PGC1α significantly inhibited the proliferation of DOKs in vitro and tumor growth in vivo, induced S-phase arrest, and suppressed PI3K/Akt signaling pathway without affecting cell apoptosis. Mechanistically, downregulated of PGC1α decreased mtDNA, ETC, and OCR, while enhancing ROS, glucose uptake, ECAR, and glycolysis by regulating lactate dehydrogenase A (LDHA). Moreover, SR18292 (an inhibitor of PGC1α) induced oxidative phosphorylation dysfunction of DOKs and declined DOK xenograft tumor progression. Thus, our work suggests that PGC1α plays a crucial role in cell proliferation by reprograming energy metabolism and interfering with energy metabolism, acting as a potential therapeutic target for OPMDs.

DDQN-based optimal targeted therapy with reversible inhibitors to combat the Warburg effect

We cover the Warburg effect with a three-component evolutionary model, where each component represents a different metabolic strategy. In this context, a scenario involving cells expressing three different phenotypes is presented. One tumour phenotype exhibits glycolytic metabolism through glucose uptake and lactate secretion. Lactate is used by a second malignant phenotype to proliferate. The third phenotype represents healthy cells, which performs oxidative phosphorylation. The purpose of this model is to gain a better understanding of the metabolic alterations associated with the Warburg effect. It is suitable to reproduce some of the clinical trials obtained in colorectal cancer and other even more aggressive tumours. It shows that lactate is an indicator of poor prognosis, since it favours the setting of polymorphic tumour equilibria that complicates its treatment. This model is also used to train a reinforcement learning algorithm, known as Double Deep Q-networks, in order to provide the first optimal targeted therapy based on experimental tumour growth inhibitors as genistein and AR-C155858. Our in silico solution includes the optimal therapy for all the tumour state space and also ensures the best possible quality of life for the patients, by considering the duration of treatment, the use of low-dose medications and the existence of possible contraindications. Optimal therapies obtained with Double Deep Q-networks are validated with the solutions of the Hamilton-Jacobi-Bellman equation.

Prognostic significance of lactate dehydrogenase and its impact on the outcomes of gastric cancer: a systematic review and meta-analysis

Background

The prognostic significance of lactate dehydrogenase (LDH) and its impact on the outcomes of gastric cancer (GC) is still unclear. We assessed the link between the levels of LDH and the overall survival (OS) and disease-free survival (DFS) in GC patients.

Methods

A comprehensive search (both electronic and manual) was carried out in PubMed via MEDLINE, Web of Science (WoS), Experta Medical Database (Embase), and CENTRAL (Cochrane Library) databases for citations that evaluated the strength of association between LDH cut-off levels and OS and/or DFS in GC. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and heterogeneity was assessed.

Results

Eighteen studies with 5328 patients were included in our review. The overall pooled HR for OS was 1.48 (95% CI: 1.22-1.80) with high heterogeneity (I2 = 86%). Subgroup analyses showed that the link between LDH and OS was more prominent in Caucasian (HR 1.50 95% CI [0.80, 2.81], p=0.21) than in Asian cohorts (HR, 1.51 95% CI [1.21, 1.87], p=0.002). No significant overall association between LDH and OS (HR = 1.12, 95% CI: 0.76-1.65, p = 0.58) was found. Similar subgroup analyses results were reported for the association between LDH and DFS.

Conclusion

In patients with GC, elevated LDH levels may correlate with worse OS and DFS, but the association is not significant. LDH is a significant predictor of OS but not of DFS. Further studies with larger sample sizes and more standardized criteria for defining elevated LDH levels are needed to confirm our findings.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023412449.

Associations of lactate dehydrogenase with risk of renal outcomes and cardiovascular mortality in individuals with diabetic kidney disease

OBJECTIVE

This study aimed to investigate the role of the lactate dehydrogenase (LDH) in the development of end-stage renal disease (ESRD) and the cardiovascular mortality in individuals with diabetic kidney disease (DKD).

METHODS

Two cohorts were recruited in this study. We explored the correlation between LDH and renal injury in individuals with DKD in using a Cohort 1. Additionally, we validated this correlation in the NHANES database and further investigated its association with the risk of cardiovascular mortality in Cohort 2 which also comprised individuals with DKD.

RESULTS

In cohort 1, multivariate Cox regression analysis demonstrated that individuals in DKD with higher LDH were independently associated with an increased risk of ESRD compared to those with lower LDH (HR = 2.11; 95 % CI, 1.07-4.16). In cohort 2, linear regression models showed that LDH affects the level of albumin-creatinine ratio (ACR) (β = 2.95, P = 0.001). Additionally, multivariate Cox regression analysis results showed that an increase in LDH per 1-standard deviation (SD) was associated with a 27 % increased risk of cardiovascular mortality (HR = 1.27; 95 % CI, 1.09-1.48).

CONCLUSIONS

LDH levels are associated with renal injury and progression to ESRD, as well as being an independent risk factor for cardiovascular in individuals with DKD.

Bioenergetic alteration in gastrointestinal cancers: The good, the bad and the ugly

Cancer cells exhibit metabolic reprogramming and bioenergetic alteration, utilizing glucose fermentation for energy production, known as the Warburg effect. However, there are a lack of comprehensive reviews summarizing the metabolic reprogramming, bioenergetic alteration, and their oncogenetic links in gastrointestinal (GI) cancers. Furthermore, the efficacy and treatment potential of emerging anticancer drugs targeting these alterations in GI cancers require further evaluation. This review highlights the interplay between aerobic glycolysis, the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (OXPHOS) in cancer cells, as well as hypotheses on the molecular mechanisms that trigger this alteration. The role of hypoxia-inducible transcription factors, tumor suppressors, and the oncogenetic link between hypoxia-related enzymes, bioenergetic changes, and GI cancer are also discussed. This review emphasizes the potential of targeting bioenergetic regulators for anti-cancer therapy, particularly for GI cancers. Emphasizing the potential of targeting bioenergetic regulators for GI cancer therapy, the review categorizes these regulators into aerobic glycolysis/ lactate biosynthesis/transportation and TCA cycle/coupled OXPHOS. We also detail various anti-cancer drugs and strategies that have produced pre-clinical and/or clinical evidence in treating GI cancers, as well as the challenges posed by these drugs. Here we highlight that understanding dysregulated cancer cell bioenergetics is critical for effective treatments, although the diverse metabolic patterns present challenges for targeted therapies. Further research is needed to comprehend the specific mechanisms of inhibiting bioenergetic enzymes, address side effects, and leverage high-throughput multi-omics and spatial omics to gain insights into cancer cell heterogeneity for targeted bioenergetic therapies.

Phospho-DIGE Identified Phosphoproteins Involved in Pathways Related to Tumour Growth in Endometrial Cancer

Endometrial cancer (EC) is the most common gynecologic malignancy of the endometrium. This study focuses on EC and normal endometrium phosphoproteome to identify differentially phosphorylated proteins involved in tumorigenic signalling pathways which induce cancer growth. We obtained tissue samples from 8 types I EC at tumour stage 1 and 8 normal endometria. We analyzed the phosphoproteome by two-dimensional differential gel electrophoresis (2D-DIGE), combined with immobilized metal affinity chromatography (IMAC) and mass spectrometry for protein and phosphopeptide identification. Quantities of 34 phosphoproteins enriched by the IMAC approach were significantly different in the EC compared to the endometrium. Validation using Western blotting analysis on 13 patients with type I EC at tumour stage 1 and 13 endometria samples confirmed the altered abundance of HBB, CKB, LDHB, and HSPB1. Three EC samples were used for in-depth identification of phosphoproteins by LC-MS/MS analysis. Bioinformatic analysis revealed several tumorigenic signalling pathways. Our study highlights the involvement of the phosphoproteome in EC tumour growth. Further studies are needed to understand the role of phosphorylation in EC. Our data shed light on mechanisms that still need to be ascertained but could open the path to a new class of drugs that could hinder EC growth.

The Warburg effect: a score for many instruments in the concert of cancer and cancer niche cells

Although Warburg's discovery of intensive glucose uptake by tumors, followed by lactate fermentation in oxygen presence of oxygen was made a century ago, it is still an area of intense research and development of new hypotheses that, layer by layer, unravel the complexities of neoplastic transformation. This seemingly simple metabolic reprogramming of cancer cells reveals an intriguing, multi-faceted nature that may link various phenomena including cell signaling, cell proliferation, ROS generation, energy supply, macromolecules synthesis/biosynthetic precursor supply, immunosuppression, or cooperation of cancerous cells with cancer-associated fibroblasts (CAFs), known as reversed Warburg effect. According to the current perception of the causes and consequences of the Warburg effect, PI3K/Akt/mTOR are the main signaling pathways that, in concert with the transcription factors HIF-1, p53, and c-Myc, modulate the activity/expression of key regulatory enzymes, including PKM2, and PDK1 to tune in the most optimal metabolic setting for the cancer cell. This in turn secures adequate levels of biosynthetic precursors, NADPH, NAD⁺, and rapid ATP production to meet the increased demands of intensively proliferating tumor cells. The end-product of "aerobic glycolysis", lactate, an oncometabolite, may provide fuel to neighboring cancer cells, and facilitate metastasis and immunosuppression together enabling cancer progression. The importance and possible applicability of the presented issue are best illustrated by numerous trials with various agents targeting the Warburg effect, constituting a promising strategy in future anti-cancer regimens. In this review, we present the key aspects of this multifactorial phenomenon, depicting the mechanisms and benefits behind the Warburg effect, and also pointing to selected aspects in the field of anticancer therapy.

Melatonin blunted the angiogenic activity in 3D colon cancer tumoroids by the reduction of endocan

BACKGROUND

Complexity and heterogeneity of the tumor niche are closely associated with the failure of therapeutic protocols. Unfortunately, most data have been obtained from conventional 2D culture systems which are not completely comparable to in vivo microenvironments. Reconstructed 3D cultures composed of multiple cells are valid cell-based tumor models to recapitulate in vivo-like interaction between the cancer cells and stromal cells and the oncostatic properties of therapeutics. Here, we aimed to assess the tumoricidal properties of melatonin on close-to-real colon cancer tumoroids in in vitro conditions.

METHODS

Using the hanging drop method, colon cancer tumoroids composed of three cell lines, including adenocarcinoma HT-29 cells, fibroblasts (HFFF2), and endothelial cells (HUVECs) at a ratio of 2: 1: 1, respectively were developed using 2.5% methylcellulose. Tumoroids were exposed to different concentrations of melatonin, from 0.005 to 0.8 mM and 4 to 10 mM, for 48 h. The survival rate was measured by MTT and LDH leakage assays. Protein levels of endocan and VEGF were assessed using western blotting. Using histological examination (H & E) staining, the integrity of cells within the tumoroid parenchyma was monitored.

RESULTS

Despite the reduction of viability rate in lower doses, the structure of tumoroids remained unchanged. In contrast, treatment of tumoroids with higher doses of melatonin, 4 and 10 mM, led to disaggregation of cells and reduction of tumoroid diameter compared to the non-treated control tumoroids (p < 0.05). By increasing melatonin concentration from 4 to 10 mM, the number of necrotic cells increased. Data showed the significant suppression of endocan in melatonin-treated tumoroids related to the non-treated controls (p < 0.05). According to our data, melatonin in higher doses did not alter protein levels of VEGF (p > 0.05).

CONCLUSIONS

Melatonin can exert its tumoricidal properties on colon cancer tumoroids via the reduction of tumor cell viability and inhibition of the specific pro-angiogenesis factor.

Identification of co-regulated genes associated with doxorubicin resistance in the MCF-7/ADR cancer cell line

Introduction

The molecular mechanism of chemotherapy resistance in breast cancer is not well understood. The identification of genes associated with chemoresistance is critical for a better understanding of the molecular processes driving resistance.

Methods

This study used a co-expression network analysis of Adriamycin (or doxorubicin)-resistant MCF-7 (MCF-7/ADR) and its parent MCF-7 cell lines to explore the mechanisms of drug resistance in breast cancer. Genes associated with doxorubicin resistance were extracted from two microarray datasets (GSE24460 and GSE76540) obtained from the Gene Expression Omnibus (GEO) database using the GEO2R web tool. The candidate differentially expressed genes (DEGs) with the highest degree and/or betweenness in the co-expression network were selected for further analysis. The expression of major DEGs was validated experimentally using qRT-PCR.

Results

We identified twelve DEGs in MCF-7/ADR compared with its parent MCF-7 cell line, including 10 upregulated and 2 downregulated DEGs. Functional enrichment suggests a key role for RNA binding by IGF2BPs and epithelial-to-mesenchymal transition pathways in drug resistance in breast cancer.

Discussion

Our findings suggested that MMP1, VIM, CNN3, LDHB, NEFH, PLS3, AKAP12, TCEAL2, and ABCB1 genes play an important role in doxorubicin resistance and could be targeted for developing novel therapies by chemical synthesis approaches.

A retrospect study based on real-world data to observe metabolic function in cancer patients using albumin-bound paclitaxel

There is substantial evidence that albumin-bound paclitaxel (nab-paclitaxel) is effective and safe for the treatment of breast, lung and pancreatic cancers. However, it can still cause adverse effects by affecting cardiac enzymes, hepatic enzyme metabolism and blood routine related indicators, which affects the use of chemotherapy for a full course of treatment. However, there are no relevant clinical studies to systematically observe the effects and dynamics of albumin-bound paclitaxel on cardiac enzymes, liver enzyme metabolism, and routine blood-related indices. The purpose of our study was to determine the levels of serum creatinine (Cre), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase isoenzyme (CK-MB), white blood cells (WBC) and hemoglobin (HGB) in cancer patients treated with albumin-conjugated paclitaxel. This study retrospectively analyzed 113 patients with cancer. Patients who had received two cycles of nab-paclitaxel 260 mg/m² (administered intravenously on days 1, 8, and 15 of each 28-day cycle) were selected. Serum Cre, AST, ALT, LDH, CK, and CK-MB activities, WBC counts, and HGB levels were measured before and after treatment with two cycles. Fourteen cancer types were analyzed. The distribution of cancer types in patients was mainly concentrated in lung, ovarian, and breast cancer. Nab-paclitaxel treatment markedly decreased Cre, AST, LDH, and CK activities in the serum and WBC counts and HGB levels, respectively. Serum Cre and CK activities and HGB levels were remarkably downregulated at baseline compared to healthy controls. Patients receiving nab-paclitaxel treatment cause metabolic disorders in tumor patients by reducing the decrease of Cre, AST, LDH, CK, CK-MB, WBC and HGB indexes, thus inducing the occurrence of cardiovascular events, hepatotoxic events and fatigue and other symptoms. Therefore, for tumor patients, although receiving nab-paclitaxel improves the anti-tumor effect, it is still necessary to closely monitor the changes of related enzymatic and routine blood indicators, so as to detect and intervene at an early stage.

Early detection of plasma d-lactate: Toward a new highly-specific biomarker of bacteraemia?

Background

Bloodstream infections are a leading cause of mortality. Their detection relies on blood cultures (BCs) but time to positivity is often between tens of hours and days. d-lactate is a metabolite widely produced by bacteria but very few in human. We aimed to evaluate d-lactate, d-lactate/l-lactate ratio and d-lactate/total lactate ratio in plasma as potential early biomarkers of bacteraemia on a strictly biological standpoint.

Methods

A total of 228 plasma specimens were collected from patients who had confirmed bacteraemia (n = 131) and healthy outpatients (n = 97). Specific l-lactate and d-lactate analyses were performed using enzymatic assays and analytical performances of d-lactate, d-lactate/total lactate and d-lactate/l-lactate ratios for the diagnosis of bacteraemia were assessed.

Results

A preliminary in vitro study confirmed that all strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were able to produce d-lactate at significant levels. In patients, plasma d-lactate level was the most specific biomarker predicting a bacteraemia profile with a specificity and predictive positive value of 100% using a cut-off of 131 μmol.L^-1. However, sensitivity and negative predictive value were rather low, estimated at 31% and 52%, respectively. d-lactate displayed an Area Under Receiver Operating Characteristic (AUROC) curve of 0.696 with a P value < 0.0001. There was no difference of d-lactate levels between BCs bottles positive for Gram-positive or Gram-negative bacteria (p = 0.55).

Conclusion

d-lactate shows promise as a specific early biomarker of bacterial metabolism. The development of rapid automated assays could raise clinical applications for infectious diseases diagnosis including early bacteraemia prediction.

Shape and Shear Stress Impact on the Toxicity of Mesoporous Silica Nanoparticles: In Vitro and In Vivo Evidence

Mesoporous silica nanoparticles (MSNs) are widely used in the biomedical field because of their unique and excellent properties. However, the potential toxicity of different shaped MSNs via injection has not been fully studied. This study aims to systematically explore the impact of shape and shear stress on the toxicity of MSNs after injection. An in vitro blood flow model was developed to investigate the cytotoxicity and the underlying mechanisms of spherical MSNs (S-MSN) and rodlike MSNs (R-MSN) in human umbilical vein endothelial cells (HUVECs). The results suggested that the interactions between MSNs and HUVECs under the physiological flow conditions were significantly different from that under static conditions. Whether under static or flow conditions, R-MSN showed better cellular uptake and less oxidative damage than S-MSN. The main mechanism of cytotoxicity induced by R-MSN was due to shear stress-dependent mechanical damage of the cell membrane, while the toxicity of S-MSN was attributed to mechanical damage and oxidative damage. The addition of fetal bovine serum (FBS) alleviated the toxicity of S-MSN by reducing cellular uptake and oxidative stress under static and flow conditions. Moreover, the in vivo results showed that both S-MSN and R-MSN caused cardiovascular toxicity in zebrafish and mouse models due to the high shear stress, especially in the heart. S-MSN led to severe oxidative damage at the accumulation site, such as liver, spleen, and lung in mice, while R-MSN did not cause significant oxidative stress. The results of in vitro blood flow and in vivo models indicated that particle shape and shear stress are crucial to the biosafety of MSNs, providing new evidence for the toxicity mechanisms of the injected MSNs.

Metabolic Effects of New Glucose Transporter (GLUT-1) and Lactate Dehydrogenase-A (LDH-A) Inhibitors against Chemoresistant Malignant Mesothelioma

Malignant mesothelioma (MM) is a highly aggressive and resistant tumor. The prognostic role of key effectors of glycolytic metabolism in MM prompted our studies on the cytotoxicity of new inhibitors of glucose transporter type 1 (GLUT-1) and lactate dehydrogenase-A (LDH-A) in relation to ATP/NAD⁺ metabolism, glycolysis and mitochondrial respiration. The antiproliferative activity of GLUT-1 (PGL13, PGL14) and LDH-A (NHI-1, NHI-2) inhibitors, alone and in combination, were tested with the sulforhodamine-B assay in peritoneal (MESO-II, STO) and pleural (NCI-H2052 and NCI-H28) MM and non-cancerous (HMEC-1) cells. Effects on energy metabolism were measured by both analysis of nucleotides using RP-HPLC and evaluation of glycolysis and respiration parameters using a Seahorse Analyzer system. All compounds reduced the growth of MM cells in the µmolar range. Interestingly, in H2052 cells, PGL14 decreased ATP concentration from 37 to 23 and NAD⁺ from 6.5 to 2.3 nmol/mg protein. NHI-2 reduced the ATP/ADP ratio by 76%. The metabolic effects of the inhibitors were stronger in pleural MM and in combination, while in HMEC-1 ATP reduction was 10% lower compared to that of the H2052 cells, and we observed a minor influence on mitochondrial respiration. To conclude, both inhibitors showed cytotoxicity in MM cells, associated with a decrease in ATP and NAD⁺, and were synergistic in the cells with the highest metabolic modulation. This underlines cellular energy metabolism as a potential target for combined treatments in selected cases of MM.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

Targeted lactate dehydrogenase genes silencing in probiotic lactic acid bacteria: A possible paradigm shift in colorectal cancer treatment?

Even though the pathophysiology of colorectal cancer (CRC) is complicated and poorly understood, interactions between risk factors appear to be key in the development and progression of the malignancy. The popularity of using lactic acid bacteria (LAB) prebiotics and probiotics to modulate the tumor microenvironment (TME) has grown widely over the past decade. The objective of this study was therefore to determine the detrimental effects of LAB-derived lactic acid in the colonic mucosa in colorectal cancer management. Six library databases and a web search engine were used to execute a structured systematic search of the existing literature, considering all publications published up until August 2022. A total of 7817 papers were screened, all of which were published between 1995 and August 2022. However, only 118 articles met the inclusion criterion. Lactic acid has been directly linked to the massive proliferation of cancerous cells since the glycolytic pathway provides cancerous cells with not only ATP, but also biosynthetic intermediates for rapid growth and proliferation. Our research suggests that targeting LAB metabolic pathways is capable of suppressing tumor growth and that the LDH gene is critical for tumorigenesis. Silencing of Lactate dehydrogenase, A (LDHA), B (LDHB), (LDHL), and hicD genes should be explored to inhibit fermentative glycolysis yielding lactic acid as the by-product. More studies are necessary for a solid understanding of this topic so that LAB and their corresponding lactic acid by-products do not have more adverse effects than their widely touted positive outcomes in CRC management.

RNA Sequencing in Hypoxia-Adapted T98G Glioblastoma Cells Provides Supportive Evidence for IRE1 as a Potential Therapeutic Target

Glioblastoma (GBM) is an aggressive brain cancer with a median survival time of 14.6 months after diagnosis. GBM cells have altered metabolism and exhibit the Warburg effect, preferentially producing lactate under aerobic conditions. After standard-of-care treatment for GBM, there is an almost 100% recurrence rate. Hypoxia-adapted, treatment-resistant GBM stem-like cells are thought to drive this high recurrence rate. We used human T98G GBM cells as a model to identify differential gene expression induced by hypoxia and to search for potential therapeutic targets of hypoxia adapted GBM cells. RNA sequencing (RNAseq) and bioinformatics were used to identify differentially expressed genes (DEGs) and cellular pathways affected by hypoxia. We also examined expression of lactate dehydrogenase (LDH) genes using qRT-PCR and zymography as LDH dysregulation is a feature of many cancers. We found 2630 DEGs significantly altered by hypoxia (p < 0.05), 1241 upregulated in hypoxia and 1389 upregulated in normoxia. Hypoxia DEGs were highest in pathways related to glycolysis, hypoxia response, cell adhesion and notably the endoplasmic reticulum, including the inositol-requiring enzyme 1 (IRE1)-mediated unfolded protein response (UPR). These results, paired with numerous published preclinical data, provide additional evidence that inhibition of the IRE1-mediated UPR may have therapeutic potential in treating GBM. We propose a possible drug repurposing strategy to simultaneously target IRE1 and the spleen tyrosine kinase (SYK) in patients with GBM.

ALDOC- and ENO2- driven glucose metabolism sustains 3D tumor spheroids growth regardless of nutrient environmental conditions: a multi-omics analysis

BACKGROUND

Metastases are the major cause of cancer-related morbidity and mortality. By the time cancer cells detach from their primary site to eventually spread to distant sites, they need to acquire the ability to survive in non-adherent conditions and to proliferate within a new microenvironment in spite of stressing conditions that may severely constrain the metastatic process. In this study, we gained insight into the molecular mechanisms allowing cancer cells to survive and proliferate in an anchorage-independent manner, regardless of both tumor-intrinsic variables and nutrient culture conditions.

METHODS

3D spheroids derived from lung adenocarcinoma (LUAD) and breast cancer cells were cultured in either nutrient-rich or -restricted culture conditions. A multi-omics approach, including transcriptomics, proteomics, and metabolomics, was used to explore the molecular changes underlying the transition from 2 to 3D cultures. Small interfering RNA-mediated loss of function assays were used to validate the role of the identified differentially expressed genes and proteins in H460 and HCC827 LUAD as well as in MCF7 and T47D breast cancer cell lines.

RESULTS

We found that the transition from 2 to 3D cultures of H460 and MCF7 cells is associated with significant changes in the expression of genes and proteins involved in metabolic reprogramming. In particular, we observed that 3D tumor spheroid growth implies the overexpression of ALDOC and ENO2 glycolytic enzymes concomitant with the enhanced consumption of glucose and fructose and the enhanced production of lactate. Transfection with siRNA against both ALDOC and ENO2 determined a significant reduction in lactate production, viability and size of 3D tumor spheroids produced by H460, HCC827, MCF7, and T47D cell lines.

CONCLUSIONS

Our results show that anchorage-independent survival and growth of cancer cells are supported by changes in genes and proteins that drive glucose metabolism towards an enhanced lactate production. Notably, this finding is valid for all lung and breast cancer cell lines we have analyzed in different nutrient environmental conditions. broader Validation of this mechanism in other cancer cells of different origin will be necessary to broaden the role of ALDOC and ENO2 to other tumor types. Future in vivo studies will be necessary to assess the role of ALDOC and ENO2 in cancer metastasis.

A review on the roles and molecular mechanisms of MAFG-AS1 in oncogenesis

Long non-coding RNAs (lncRNAs) have more than 200 nucleotides and do not encode proteins. At the same time, they can regulate various biological functions and therefore play an essential role as oncogenes or tumor suppressors in human cancers. MAFG-AS1 is an antisense RNA of MAF BZIP Transcription Factor G (MAFG) located at chromosome 17q25.3 head-to-head with the MAFG encoding gene containing a transcript size of 1895 bp. Accumulating evidence shows that MAFG-AS1 is overexpressed in many cancers, functions as an oncogene, and is significantly associated with poor clinical characteristics and prognosis. In this review, we first discuss the recent literature regarding the role of MAFG-AS1 in different cancers as well as its diagnostic and prognostic values. Then we will provide insights into its biological functions, such as its role in cancer progression, competing endogenous RNA (ceRNA) activity, regulation of EMT, glycolysis, energy metabolism, transcription factors, proteasomal degradation, and signaling pathways.

Secretome of Stromal Cancer-Associated Fibroblasts (CAFs): Relevance in Cancer

The cancer secretome reflects the assortment of proteins released by cancer cells. Investigating cell secretomes not only provides a deeper knowledge of the healthy and transformed state but also helps in the discovery of novel biomarkers. Secretomes of cancer cells have been studied in the past, however, the secretome contribution of stromal cells needs to be studied. Cancer-associated fibroblasts (CAFs) are one of the predominantly present cell populations in the tumor microenvironment (TME). CAFs play key role in functions associated with matrix deposition and remodeling, reciprocal exchange of nutrients, and molecular interactions and signaling with neighboring cells in the TME. Investigating CAFs secretomes or CAFs-secreted factors would help in identifying novel CAF-specific biomarkers, unique druggable targets, and an improved understanding for personalized cancer diagnosis and prognosis. In this review, we have tried to include all studies available in PubMed with the keywords "CAFs Secretome". We aim to provide a comprehensive summary of the studies investigating role of the CAF secretome on cancer development, progression, and therapeutic outcome. However, challenges associated with this process have also been addressed in the later sections. We have highlighted the functions and clinical relevance of secretome analysis in stromal CAF-rich cancer types. This review specifically discusses the secretome of stromal CAFs in cancers. A deeper understanding of the components of the CAF secretome and their interactions with cancer cells will help in the identification of personalized biomarkers and a more precise treatment plan.

Prognostic Significance of Preoperative Lactate Dehydrogenase to Albumin Ratio in Breast Cancer: A Retrospective Study

Purpose

We explored the relationship between platelet count to lymphocyte count ratio (PLR), monocyte count to lymphocyte count ratio (MLR), lactate dehydrogenase to albumin ratio (LAR), and long-term survival in patients with breast cancer.

Patients and Methods

We retrospectively analyzed the clinical and follow-up data of 134 patients with breast cancer. The receiver operating characteristic curve (ROC curve) was used to distinguish between the low and high ratio groups. The chi-square test or Fisher's exact test was used to calculate the differences among the investigation factors. The Kaplan-Meier method was used to draw the survival curves. Log rank test was used for univariate analysis, and Cox proportional hazards regression model was used for multivariate analysis. A P value of <0.05 was considered statistically significant.

Results

The median follow-up time was 45 months. The PFS rates in the low group (LAR≤3.4066) at 18 months, 24 months, and 36 months were 100%, 100%, and 97.6%, and those in the high group (LAR > 3.4066) were 97.7%, 94.3%, and 87.3%, respectively. LAR was associated with Age (P=0.002) and BMI (body mass index) (P=0.002). Univariate analysis showed that Tumor size (P=0.027), Node positivity (P<0.001), TNM (tumor-node-metastasis) stage (P<0.001), PLR (P=0.034), MLR (P=0.038), and LAR (P=0.035) were significantly associated with PFS (progression-free survival) in breast cancer patients. Multivariate analysis showed that Node positivity (P<0.001) and LAR (P=0.035) were associated with PFS, while PLR and MLR were not independent prognostic indicators.

Conclusion

Preoperative high LAR will be an independent predictor of prognosis in patients with breast cancer.

Long noncoding RNAs: glycolysis regulators in gynaecologic cancers

The three most common gynaecologic cancers that seriously threaten female lives and health are ovarian cancer, cervical cancer, and endometrial cancer. Glycolysis plays a vital role in gynaecologic cancers. Several long noncoding RNAs (lncRNAs) are known to function as oncogenic molecules. LncRNAs impact downstream target genes by acting as ceRNAs, guides, scaffolds, decoys, or signalling molecules. However, the role of glycolysis-related lncRNAs in regulating gynaecologic cancers remains poorly understood. In this review, we emphasize the functional roles of many lncRNAs that have been found to promote glycolysis in gynaecologic cancers and discuss reasonable strategies for future research.