Mitochondrial pyruvate carrier 1 expression controls cancer epithelial-mesenchymal transition and radioresistance

MPC2 Overexpression Drives Mitochondrial Oxidative Phosphorylation and Promotes Progression in Diffuse Large B-Cell Lymphoma

Diffuse Large B-Cell Lymphoma (DLBCL) is an aggressive form of non-Hodgkin lymphoma with heterogeneous molecular characteristics. Altered metabolism, particularly mitochondrial function, has emerged as a critical factor in cancer progression. However, the role of mitochondrial metabolism in DLBCL remains poorly understood. This study aimed to identify key mitochondrial factors associated with DLBCL progression. We analyzed transcriptomic data from multiple DLBCL datasets (GSE83632, TCGA-GTEX, GSE181063, GSE4475) using differential expression analysis, weighted gene co-expression network analysis (WGCNA), and Gene Set Enrichment Analysis (GSEA). The expression and function of the identified key factor, Mitochondrial Pyruvate Carrier 2 (MPC2), were validated using clinical samples, DLBCL cell lines, and an in vivo mouse model of xenograft. Integrative bioinformatics analysis identified MPC2 as a significantly upregulated gene in DLBCL, associated with enrichment of oxidative phosphorylation (OXPHOS) and cell cycle-related genes. MPC2 overexpression was confirmed in clinical DLBCL samples and cell lines at both mRNA and protein levels. Knockdown of MPC2 in DLBCL cells impaired mitochondrial OXPHOS, increased glycolysis, and suppressed cell proliferation, invasion, and 3D spheroid formation. In vivo, MPC2 silencing significantly reduced tumor growth in a xenograft mouse model. Our findings reveal MPC2 as a key regulator of mitochondrial function in DLBCL, promoting tumor progression through enhanced OXPHOS. This study provides new insights into the metabolic reprogramming of DLBCL and suggests MPC2 as a potential therapeutic target for this aggressive lymphoma.

Integrative pan-cancer analysis and experiment validation identified GLS as a biomarker in tumor progression, prognosis, immune microenvironment, and immunotherapy

Glutaminase (GLS), a crucial gene regulating glutaminolysis, has received much attention as it was found to regulate tumor metabolism and copper-induced cell death. However, its biological roles and mechanisms in human cancers remain obscure. Consequently, the integrated pan-cancer analyses and biological experiments were conducted to elucidate its oncological functions. We found GLS was differentially expressed in human cancers and upregulated GLS predicted poor survival, clinicopathological progression, and tumor heterogeneity. Single-cell analysis found GLS was closely related to various biological functions and pathways. Spatial transcriptomic analysis found GLS expression was mainly derived from tumor cells, which implies tumor cells may have a stronger ability to utilize glutamine than antitumor immune cells in the tumor microenvironment (TME). Meanwhile, we noticed GLS expression was strongly related to the infiltration of various immune cells and stromal cells, the expression of immunomodulatory genes, the activity of some conventional antitumor agents, and the therapeutic response of immunotherapy. Moreover, enrichment analyses suggested GLS was related to various metabolic reprogramming, innate and adaptive immunity suppression, and extracellular matrix remodeling. Finally, we observed GLS was highly expressed in our gastric cancer (GC) cohort. As an independent risk factor for GC prognosis, high-GLS was closely related to pathological progression. Inhibiting GLS expression in GC cells effectively prevented proliferation, migration, and invasion and triggered apoptosis. In conclusion, GLS is an underlying biomarker for oncological progression, prognosis, TME, antitumor drug sensitivity, and immunotherapy response. Targeting GLS can facilitate the implementation of individualized and combined treatment strategies.

Pentagalloyl Glucose from Bouea macrophylla Suppresses the Epithelial-Mesenchymal Transition and Synergizes the Doxorubicin-Induced Anticancer and Anti-Migration Effects in Triple-Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) represents an aggressive form of breast cancer with few available therapeutic options. Chemotherapy, particularly with drugs like doxorubicin (DOX), remains the cornerstone of treatment for this challenging subtype. However, the clinical utility of DOX is hampered by adverse effects that escalate with higher doses and drug resistance, underscoring the need for alternative therapies. This study explored the efficacy of pentagalloyl glucose (PGG), a natural polyphenol derived from Bouea macrophylla, in enhancing DOX's anticancer effects and suppressing the epithelial-mesenchymal transition (EMT) in TNBC cells. Methods: This study employed diverse methodologies to assess the effects of PGG and DOX on TNBC cells. MDA-MB231 triple-negative breast cancer cells were used to evaluate cell viability, migration, invasion, apoptosis, mitochondrial membrane potential, and protein expression through techniques including MTT assays, wound healing assays, flow cytometry, Western blotting, and immunofluorescence. Results: Our findings demonstrate that PGG combined with DOX significantly inhibits TNBC cell proliferation, migration, and invasion. PGG enhances DOX-induced apoptosis by disrupting the mitochondrial membrane potential and activating caspase pathways; consequently, the activation of caspase-3 and the cleavage of PARP are increased. Additionally, the study shows that the combination treatment upregulates ERK signaling, further promoting apoptosis. Moreover, PGG reverses DOX-induced EMT by downregulating mesenchymal markers (vimentin and β-catenin) and upregulating epithelial markers (E-cadherin). Furthermore, it effectively inhibits STAT3 phosphorylation, associated with cell survival and migration. Conclusions: These results highlight the potential of PGG as an adjuvant therapy in TNBC treatment. PGG synergizes with DOX, which potentiates its anticancer effects while mitigating adverse reactions.

Unveiling therapeutic avenues targeting xCT in head and neck cancer

Head and neck cancer (HNC) remains a major global health burden, prompting the need for innovative therapeutic strategies. This review examines the role of the cystine/glutamate antiporter (xCT) in HNC, specifically focusing on how xCT contributes to cancer progression through mechanisms such as redox imbalance, ferroptosis, and treatment resistance. The central questions addressed include how xCT dysregulation affects tumor biology and the potential for targeting xCT to enhance treatment outcomes. We explore recent developments in xCT-targeted current and emerging therapies, including xCT inhibitors and novel treatment modalities, and their role in addressing therapeutic challenges. This review aims to provide a comprehensive analysis of xCT as a therapeutic target and to outline future directions for research and clinical application.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Exploring MPC1 as a potential ferroptosis-linked biomarker in the cervical cancer tumor microenvironment: a comprehensive analysis

BACKGROUND

The increasing problems of drug and radiotherapy resistance in cervical cancer underscores the need for novel methods for its management. Reports indicate that the expression of MPC1 may be associated with the tumor microenvironment and the occurrence of ferroptosis in cervical cancer. The objective of this study was to visually illustrate the prognostic significance and immunological characterization of MPC1 in cervical cancer.

METHODS

The expression profile and prognostic significance of MPC1 were analyzed using various databases, including UALCAN, TIMER2, GEPIA2, and Kaplan-Meier Plotter. TISIDB, TIMER2, and immunohistochemical analysis were used to investigate the correlation between MPC1 expression and immune infiltration. GO enrichment analysis, KEGG analysis, Reactome analysis, ConsensusPathDB, and GeneMANIA were used to visualize the functional enrichment of MPC1 and signaling pathways related to MPC1. The correlation analysis was carried out to examine the relationship between MPC1 and Ferroptosis gene in TIMER 2.0, ncFO, GEPIA Database and Kaplan-Meier Plotter.

RESULTS

We demonstrated that the expression levels of MPC1 in cervical cancer tissues were lower than those in normal cervical tissues. Kaplan-Meier survival curves showed shorter overall survival in cervical cancer patients with low levels of MPC1 expression. The expression of MPC1 was related to the infiltrating levels of tumor-infiltrating immune cells in cervical cancer. Moreover, MPC1 expression was associated with the iron-mediated cell death pathway, and several important ferroptosis genes were upregulated in cervical cancer cells. Furthermore, after knocking down MPC1 in HeLa cells, the expression of these genes decreased.

CONCLUSION

These findings indicate that MPC1 functions as a prognostic indicator and plays a role in the regulation of the ferroptosis pathway in cervical cancer.

Pancreatic cancer tumor organoids exhibit subtype-specific differences in metabolic profiles

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease characterized by complex metabolic rewiring that enables growth in changing nutrient availability and oxygen conditions. Transcriptome-based prognostic PDAC tumor subtypes, known as 'basal-like' and 'classical' subtypes are associated with differences in metabolic gene expression including genes involved in glycolysis. Tumor subtype-specific metabolism phenotypes may provide new targets for treatment development in PDAC, but their functional relevance has not been fully elucidated. We aimed to investigate differences in metabolic profiles and transcriptomes in tumor models derived from patients with basal-like and classical tumors.

METHODS

Patient-derived organoids (PDOs) were established from tumor biopsies collected from patients with metastatic PDAC, including three PDOs from basal-like and five PDOs from classical tumors. Metabolic analyses included assessment of differences in metabolic activity using Seahorse Glycolysis and Mito Stress tests and 13C-glucose metabolites tracing analysis. In order to investigate the influence of mitochondrial pyruvate transport on metabolic differences, PDOs were treated with the mitochondrial pyruvate carrier 1 (MPC1) inhibitor UK-5099. Prognostic relevance of MPC1 was determined using a tumor tissue microarray (TMA) in resectable, and proteomics profiling in metastatic PDAC datasets. Whole genome and transcriptome sequencing, differential gene expression and gene set enrichment analyses were performed in PDOs.

RESULTS

Metastatic PDAC PDOs showed subtype-specific differences in glycolysis and oxidative phosphorylation (OXPHOS). Basal-like tumor-derived PDOs had a lower baseline extracellular acidification rate, but higher glycolytic reserves and oxygen consumption rate (OCR) than classical tumor-derived PDOs. OCR difference was eliminated following treatment with UK-5099. In the 13C-glucose metabolites tracing experiment, a basal-like tumor PDO showed lower fractions of some M + 2 metabolites but higher sensitivity to UK-5099 mediated reduction in M + 2 metabolites than a classical tumor PDO. Protein level analyses revealed lower MPC1 protein levels in basal-like PDAC cases and association of low MPC1 levels with clinicopathologic parameters of tumor aggressiveness in PDAC. PDO differential gene expression analyses identified additional subtype-specific cellular pathways and potential disease outcome biomarkers.

CONCLUSIONS

Our findings point to distinct metabolic profiles in PDAC subtypes with basal-like tumor PDOs showing higher OXPHOS and sensitivity to MPC1 inhibition. Subtypes-specific metabolic vulnerabilities may be exploited for selective therapeutic targeting.

Role of Exosomes in Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is a fundamental process driving cancer metastasis, transforming non-motile cells into a motile population that migrates to distant organs and forms secondary tumors. In recent years, cancer research has revealed a strong connection between exosomes and the EMT. Exosomes, a subpopulation of extracellular vesicles, facilitate cellular communication and dynamically regulate various aspects of cancer metastasis, including immune cell suppression, extracellular matrix remodeling, metastasis initiation, EMT initiation, and organ-specific metastasis. Tumor-derived exosomes (TEXs) and their molecular cargo, comprising proteins, lipids, nucleic acids, and carbohydrates, are essential components that promote EMT in cancer. TEXs miRNAs play a crucial role in reprogramming the tumor microenvironment, while TEX surface integrins contribute to organ-specific metastasis. Exosome-based cancer metastasis research offers a deeper understanding about cancer and an effective theranostic platform development. Additionally, various therapeutic sources of exosomes are paving the way for innovative cancer treatment development. In this Review, we spotlight the role of exosomes in EMT and their theranostic impact, aiming to inspire cancer researchers worldwide to explore this fascinating field in more innovative ways.

The role and prospect of lysine-specific demethylases in cancer chemoresistance

Histone methylation plays a key function in modulating gene expression, and preserving genome integrity and epigenetic inheritance. However, aberrations of histone methylation are commonly observed in human diseases, especially cancer. Lysine methylation mediated by histone methyltransferases can be reversed by lysine demethylases (KDMs), which remove methyl marks from histone lysine residues. Currently, drug resistance is a main impediment for cancer therapy. KDMs have been found to mediate drug tolerance of many cancers via altering the metabolic profile of cancer cells, upregulating the ratio of cancer stem cells and drug-tolerant genes, and promoting the epithelial-mesenchymal transition and metastatic ability. Moreover, different cancers show distinct oncogenic addictions for KDMs. The abnormal activation or overexpression of KDMs can alter gene expression signatures to enhance cell survival and drug resistance in cancer cells. In this review, we describe the structural features and functions of KDMs, the KDMs preferences of different cancers, and the mechanisms of drug resistance resulting from KDMs. We then survey KDM inhibitors that have been used for combating drug resistance in cancer, and discuss the opportunities and challenges of KDMs as therapeutic targets for cancer drug resistance.

Impact of Positive-Margin Resection of External Auditory Canal Squamous Cell Carcinoma

BACKGROUND

Positive-margin resection of external auditory canal squamous cell carcinoma (EAC-SCC) is still a major cause of recurrence. The aim of this study is to examine the clinical impact of positive-margin resection of EAC-SCCs.

METHODS

We retrospectively reviewed 40 surgical cases with en bloc temporal bone resection of EAC-SCC at a tertiary referral center from October 2016 to March 2022.

RESULTS

Two-year disease-specific, overall, and disease-free survival rates for all 40 cases reviewed were 85.2%, 88.85%, and 76.96%, respectively. En bloc resection with a negative margin significantly improved patient prognosis (p < 0.001). Positive-margin resection was observed in 9/40 cases (22.5%). Insufficient assessment of preoperative images was the cause in two of these cases. Postoperative lymph node metastasis and distant metastasis were observed in cases in which vascular, lymphatic duct or perineural invasion was found on postoperative pathological examination. In addition, three cases in which no vascular, lymphatic duct, or perineural invasion was found exhibited local recurrence during the follow-up period. Of the nine positive-margin resection cases, only two showed no postoperative recurrence.

CONCLUSIONS

Once positive-margin resections are confirmed, cases might have a high risk of tumor recurrence, even with the addition of postoperative adjuvant chemoradiotherapy.

NMR and Patch-Clamp Characterization of Yeast Mitochondrial Pyruvate Carrier Complexes

The mitochondrial pyruvate carrier (Mpc) plays an indispensable role in the transport of pyruvates across the mitochondrial inner membrane. Despite the two distinct homologous proteins, Mpc1 and Mpc2, were identified in 2012, there are still controversies on the basic functional units and oligomeric state of Mpc complexes. In this study, yeast Mpc1 and Mpc2 proteins were expressed in a prokaryotic heterologous system. Both homo- and hetero-dimers were successfully reconstituted in mixed detergents. Interactions among Mpc monomers were recorded utilizing paramagnetic relaxation enhancement (PRE) nuclear magnetic resonance (NMR) methods. By single-channel patch-clamp assays, we discovered that both the Mpc1-Mpc2 hetero-dimer and Mpc1 homo-dimer are able to transport K⁺ ions. Furthermore, the Mpc1-Mpc2 hetero-dimer demonstrated the ability to transport pyruvates, at a rate significantly higher than that of the Mpc1 homo-dimer, indicating that it could be the basic functional unit of Mpc complexes. Our findings provide valuable insights for further structural determination and the study of the transport mechanism of Mpc complexes.

Profiling of immune responses by lactate modulation in cervical cancer reveals key features driving clinical outcome

Cervical cancer is still an important problem perplexing health management in developing countries. Previous studies have shown that cervical cancer cells show markers of aerobic glycolysis, suggesting that these tumors may secrete lactic acid. Through the biological characterization of lactate gene in tumor and its relationship with immune cells in tumor microenvironment, a lactate scoring system capable of evaluating cancer prognosis was constructed to explore the molecular mechanism of lactate metabolism disorder affecting prognosis. 29 hub genes in this study were differentially expressed in cervical cancer, including 24 genes related to lactate metabolism, LDHA in Lactate dehydrogenase (LDH) group, SLC16A3 in Monocarboxylate transporters (MCT) group and three Histone lactation modification related genes (EP300, ACAT1, ACACA). More importantly, we found that from an epigenetic point of view, histone lactation plays an important role in the pathogenesis and prognosis of cervical cancer. Mainly affect the prognosis of the disease through changes in the infiltration of plasmacytoid Dendritic Cell (pDC) and Central Memory T cell (Tcm) in the tumor immune microenvironment. Lactate inhibition may be a useful tool for anticancer therapy.

Chidamide, a novel histone deacetylase inhibitor, inhibits laryngeal cancer progression in vitro and in vivo

Although surgery is an important treatment for laryngeal cancer, surgery has a significant negative impact on the quality of life of patients, and many patients have poor tolerance to surgery. Therefore, alternative chemotherapeutic drugs are an important research hotspot. Chidamide is a histone deacetylase inhibitor that selectively inhibits the expression of type I and IIb histone deacetylases (1, 2, 3 and 10). It has a significant anticancer effect on a variety of solid tumours. This study verified the inhibitory effect of chidamide on laryngeal carcinoma. We conducted a variety of cellular and animal experiments to explore how chidamide inhibits the development of laryngeal cancer. The results showed that chidamide had significant antitumour activity against laryngeal carcinoma cells and xenografts and could induce cell apoptosis, ferroptosis and pyroptosis. This study provides a potential option for the treatment of laryngeal cancer.

Role of Mitochondrial Transporters on Metabolic Rewiring of Pancreatic Adenocarcinoma: A Comprehensive Review

Pancreatic cancer is among the deadliest cancers worldwide and commonly presents as pancreatic ductal adenocarcinoma (PDAC). Metabolic reprogramming is a hallmark of PDAC. Glucose and glutamine metabolism are extensively rewired in order to fulfil both energetic and synthetic demands of this aggressive tumour and maintain favorable redox homeostasis. The mitochondrial pyruvate carrier (MPC), the glutamine carrier (SLC1A5_Var), the glutamate carrier (GC), the aspartate/glutamate carrier (AGC), and the uncoupling protein 2 (UCP2) have all been shown to influence PDAC cell growth and progression. The expression of MPC is downregulated in PDAC and its overexpression reduces cell growth rate, whereas the other four transporters are usually overexpressed and the loss of one or more of them renders PDAC cells unable to grow and proliferate by altering the levels of crucial metabolites such as aspartate. The aim of this review is to comprehensively evaluate the current experimental evidence about the function of these carriers in PDAC metabolic rewiring. Dissecting the precise role of these transporters in the context of the tumour microenvironment is necessary for targeted drug development.

Novel insight into metabolic reprogrammming in cancer radioresistance: A promising therapeutic target in radiotherapy

Currently, cancer treatment mainly consists of surgery, radiotherapy, chemotherapy, immunotherapy, and molecular targeted therapy, of which radiotherapy is one of the major pillars. However, the occurrence of radioresistance largely limits its therapeutic effect. Metabolic reprogramming is an important hallmark in cancer progression and treatment resistance. In radiotherapy, DNA breakage is the major mechanism of cell damage, and in turn, cancer cells are prone to increase the metabolic flux of glucose, glutamine, serine, arginine, fatty acids etc., thus providing sufficient substrates and energy for DNA damage repair. Therefore, studying the linkage between metabolic reprogramming and cancer radioresistance may provide new ideas for improving the efficacy of tumor therapy. This review mainly focuses on the role of metabolic alterations, including glucose, amino acid, lipid, nucleotide and other ion metabolism, in radioresistance, and proposes possible therapeutic targets to improve the efficacy of cancer radiotherapy.

Metabolomics analysis and membrane damage measurement reveal the antibacterial mechanism of lipoic acid against Yersinia enterocolitica

Yersinia enterocolitica is a pathogenic microorganism that can cause food-borne diseases. Lipoic acid (LA) has been used as an antioxidant against bacteria, but its antibacterial mechanism is rarely reported. This study aims to explore the antibacterial mechanism of LA and its effect on the metabolites of Y. enterocolitica through membrane damage and metabolomics analysis. The results showed that the minimum inhibitory concentration (MIC) of LA against Y. enterocolitica was 2.5 mg mL^-1. The membrane potential was depolarized, and intracellular pH (pH_in) and ATP were significantly reduced, indicating that LA destroys the cell membrane structure. Confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM) further confirmed LA-induced cell membrane damage. The metabolic profile of Y. enterocolitica following LA treatment was analyzed by liquid chromatography-mass spectrometry (LC-MS). In the metabolome evaluation, 6209 differential metabolites were screened, including 3394 up-regulated and 2815 down-regulated metabolites. Fifteen metabolic pathways of Y. enterocolitica exhibited significant changes after LA treatment, including the pathways important for amino acid and nucleotide metabolism. The results show that LA is a bacteriostatic substance with potential application value in the food industry.

Ferroptosis and Its Multifaceted Role in Cancer: Mechanisms and Therapeutic Approach

Ferroptosis, a new type of non-apoptotic cell death modality, is different from other modes of cell death and has been primarily found in tumor cells. Previous studies have reported that ferroptosis can be triggered by specific modulators (e.g., drugs, nutrients, and iron chelators), leading to increased intracellular lipid reactive oxygen species (ROS) accumulation and iron overload. Recent reports have shown that ferroptosis at the cellular and organism levels can prevent an inflammatory storm and cancer development. Emerging evidence suggests potential mechanisms (e.g., system Xc-, glutathione peroxidase 4 (GPX4), lipid peroxidation, glutathione (GSH), and iron chelators) are involved in ferroptosis, which may mediate biological processes such as oxidative stress and iron overload to treat cancer. To date, there are at least three pathways that mediate ferroptosis in cancer cells: system Xc-/GSH/GPX4, FSP1/CoQ10/NAD(P)H, and ATG5/ATG7/NCOA4. Here, we summarize recent advances in the occurrence and development of ferroptosis in the context of cancer, the associations between ferroptosis and various modulators, and the potential mechanisms and therapeutic strategies targeting ferroptosis for the treatment of cancer.

Epithelial-Mesenchymal Transition-Mediated Tumor Therapeutic Resistance

Cancer is one of the world’s most burdensome diseases, with increasing prevalence and a high mortality rate threat. Tumor recurrence and metastasis due to treatment resistance are two of the primary reasons that cancers have been so difficult to treat. The epithelial–mesenchymal transition (EMT) is essential for tumor drug resistance. EMT causes tumor cells to produce mesenchymal stem cells and quickly adapt to various injuries, showing a treatment-resistant phenotype. In addition, multiple signaling pathways and regulatory mechanisms are involved in the EMT, resulting in resistance to treatment and hard eradication of the tumors. The purpose of this study is to review the link between EMT, therapeutic resistance, and the molecular process, and to offer a theoretical framework for EMT-based tumor-sensitization therapy.

The mitochondrial pyruvate carrier at the crossroads of intermediary metabolism

Pyruvate metabolism, a central nexus of carbon homeostasis, is an evolutionarily conserved process and aberrant pyruvate metabolism is associated with and contributes to numerous human metabolic disorders including diabetes, cancer, and heart disease. As a product of glycolysis, pyruvate is primarily generated in the cytosol before being transported into the mitochondrion for further metabolism. Pyruvate entry into the mitochondrial matrix is a critical step for efficient generation of reducing equivalents and ATP and for the biosynthesis of glucose, fatty acids, and amino acids from pyruvate. However, for many years, the identity of the carrier protein(s) that transported pyruvate into the mitochondrial matrix remained a mystery. In 2012, the molecular-genetic identification of the mitochondrial pyruvate carrier (MPC), a heterodimeric complex composed of protein subunits MPC1 and MPC2, enabled studies that shed light on the many metabolic and physiological processes regulated by pyruvate metabolism. A better understanding of the mechanisms regulating pyruvate transport and the processes affected by pyruvate metabolism may enable novel therapeutics to modulate mitochondrial pyruvate flux to treat a variety of disorders. Herein, we review our current knowledge of the MPC, discuss recent advances in the understanding of mitochondrial pyruvate metabolism in various tissue and cell types, and address some of the outstanding questions relevant to this field.

Antibacterial and Antibiofilm Activities of Chlorogenic Acid Against Yersinia enterocolitica

Nowadays, developing new and natural compounds with antibacterial activities from plants has become a promising approach to solve antibiotic resistance of pathogenic bacteria. Chlorogenic acid (CA), as a kind of phenolic acid existing in many plants, has been found to process multifunctional activities including antibacterial activity. Herein, the antibacterial and antibiofilm activities of CA against Yersinia enterocolitica (Y. enterocolitica) were tested for the first time, and its mechanism of action was investigated. It was demonstrated that CA could exert outstanding antibacterial activity against Y. enterocolitica. Biofilm susceptibility assays further indicated that CA could inhibit biofilm formation and decrease the established biofilm biomass of Y. enterocolitica. It was deduced that through binding to Y. enterocolitica, CA destroyed the cell membrane, increased the membrane permeability, and led to bacterial cell damage. In addition, the transcriptomic analysis revealed that CA could disorder many physiological pathways, mainly including the ones of antagonizing biofilms and increasing cell membrane permeability. Finally, the spiked assay showed that the growth of Y. enterocolitica in milk was significantly inhibited by CA. Taken together, CA, as an effective bactericidal effector with application potential, exerts antagonistic activity against Y. enterocolitica by mainly intervening biofilm formation and membrane permeability-related physiological pathways.

MicroRNA-200b-3p restrains gastric cancer cell proliferation, migration, and invasion via C-X-C motif chemokine ligand 12/CXC chemokine receptor 7 axis

This study was conducted to investigate the impact of microRNA (miR)-200b-3p on viability, migration, and invasion of gastric cancer (GC) cells and its mechanism. Quantitative real-time PCR (qRT-PCR) was conducted to measure miR-200b-3p expression in GC tissues and cells; besides, the relationship between miR-200b-3p expression and overall survival time (OS) was analyzed with OncomiR database; cell counting kit-8 (CCK-8), colony formation assay, flow cytometry, scratch healing assay, and Transwell assay were performed to detect the proliferation, cell cycle progression, migration, and invasion of GC cells; a lung metastasis model in nude mice was used to examine the effect of miR-200b-3p on the metastasis of GC cells in vivo; the interplay between miR-200b-3p and C-X-C motif chemokine ligand 12 (CXCL12) mRNA 3’ UTR was predicted by bioinformatics and verified with a dual-luciferase reporter gene assay; besides, the expression of CXCL12 and CXC chemokine receptor 7 (CXCR7) was probed by Western blot. It was found that miR-200b-3p expression was down-regulated in GC tissues, which was remarkably associated with the lymph node metastasis and decrease of differentiation of GC; transfection with miR-200b-3p mimics restrained the growth, migration, and invasion of GC cells in vitro, induced cell cycle arrest, and inhibited CXCL12 and CXCR7 expression levels; transfection of miR-200b-3p inhibitors worked oppositely in vitro and promoted lung metastasis in vivo. CXCL12 was confirmed as the downstream target of miR-200b-3p and was negatively modulated by miR-200b-3p. In conclusion, miR-200b-3p inhibited GC progression via regulating CXCL12/CXCR7 axis.

Factors and molecular mechanisms of radiation resistance in cancer cells

PURPOSE

The aim of this work is to review the published studies on radiation resistance mechanisms and molecular markers involved in different tumors. The revision has been focused in the last 5 years (2016-2021).

CONCLUSIONS

Radioresistance is a cause of concern as it causes failure of radiation therapy and subsequent tumor relapse. Combination chemotherapy and radiation therapy are clinically successful in treating many types of tumors. Despite continued improvements in cancer treatment, locoregional recurrence or metastatic spread continues to occur in a high proportion of patients after being treated with radiation therapy or combination treatments. There is strong evidence that cancer stem cells contribute to radiation resistance, contributing to treatment failure. The mechanisms of radiation resistance in different tumors are not fully understood. A better understanding of cancer stem cells and the associated signaling pathways that regulate radiation resistance will open up new strategies for treating cancer by radiation therapy. Radiation can damage malignant cells mainly by the induction of DNA double strand breaks. However, in some tumors appear resistant cells that repopulate the tumor following therapy leading over time to the failure of the treatment. Native mechanisms and induced pathways, are the cause of radiation resistance. It has been described that numerous molecular markers acting through numerous mechanisms of action involved in radiation resistance, such as apoptosis resistance, alterations of cell growth, proliferation and DNA repair, hypoxia, increase in invasiveness and migration capacity, cell cycle alterations and expression of heat shock proteins, among others. Therefore, resistance to radiation is a multifactorial phenomenon that, in different cell types, it occurs through different regulatory mechanisms in which different molecules intervene. Resistance can be acquired by altering different regulatory pathways in different tumors. The knowledge of radiation resistance markers could help in the classification and treatment of patients with more aggressive tumors.

Research Progress of Epithelial-mesenchymal Transition Treatment and Drug Resistance in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancies in the world that seriously affects human health. Activation of epithelial-mesenchymal transition (EMT) is a physiological phenomenon during embryonic development that is essential for cell metastasis. EMT participates in various biological processes associated with trauma repair, organ fibrosis, migration, metastasis, and infiltration of tumor cells. EMT is a new therapeutic target for CRC; however, some patients with CRC develop resistance to some drugs due to EMT. This review focuses specifically on the status of treatments that target the EMT process and its role in the therapeutic resistance observed in patients with CRC.

Impact of cancer metabolism on therapy resistance - Clinical implications

Despite an increasing arsenal of anticancer therapies, many patients continue to have poor outcomes due to the therapeutic failures and tumor relapses. Indeed, the clinical efficacy of anticancer therapies is markedly limited by intrinsic and/or acquired resistance mechanisms that can occur in any tumor type and with any treatment. Thus, there is an urgent clinical need to implement fundamental changes in the tumor treatment paradigm by the development of new experimental strategies that can help to predict the occurrence of clinical drug resistance and to identify alternative therapeutic options. Apart from mutation-driven resistance mechanisms, tumor microenvironment (TME) conditions generate an intratumoral phenotypic heterogeneity that supports disease progression and dismal outcomes. Tumor cell metabolism is a prototypical example of dynamic, heterogeneous, and adaptive phenotypic trait, resulting from the combination of intrinsic [(epi)genetic changes, tissue of origin and differentiation dependency] and extrinsic (oxygen and nutrient availability, metabolic interactions within the TME) factors, enabling cancer cells to survive, metastasize and develop resistance to anticancer therapies. In this review, we summarize the current knowledge regarding metabolism-based mechanisms conferring adaptive resistance to chemo-, radio-and immunotherapies as well as targeted therapies. Furthermore, we report the role of TME-mediated intratumoral metabolic heterogeneity in therapy resistance and how adaptations in amino acid, glucose, and lipid metabolism support the growth of therapy-resistant cancers and/or cellular subpopulations. We also report the intricate interplay between tumor signaling and metabolic pathways in cancer cells and discuss how manipulating key metabolic enzymes and/or providing dietary changes may help to eradicate relapse-sustaining cancer cells. Finally, in the current era of personalized medicine, we describe the strategies that may be applied to implement metabolic profiling for tumor imaging, biomarker identification, selection of tailored treatments and monitoring therapy response during the clinical management of cancer patients.

Biological Adaptations of Tumor Cells to Radiation Therapy

Radiation therapy has been used worldwide for many decades as a therapeutic regimen for the treatment of different types of cancer. Just over 50% of cancer patients are treated with radiotherapy alone or with other types of antitumor therapy. Radiation can induce different types of cell damage: directly, it can induce DNA single- and double-strand breaks; indirectly, it can induce the formation of free radicals, which can interact with different components of cells, including the genome, promoting structural alterations. During treatment, radiosensitive tumor cells decrease their rate of cell proliferation through cell cycle arrest stimulated by DNA damage. Then, DNA repair mechanisms are turned on to alleviate the damage, but cell death mechanisms are activated if damage persists and cannot be repaired. Interestingly, some cells can evade apoptosis because genome damage triggers the cellular overactivation of some DNA repair pathways. Additionally, some surviving cells exposed to radiation may have alterations in the expression of tumor suppressor genes and oncogenes, enhancing different hallmarks of cancer, such as migration, invasion, and metastasis. The activation of these genetic pathways and other epigenetic and structural cellular changes in the irradiated cells and extracellular factors, such as the tumor microenvironment, is crucial in developing tumor radioresistance. The tumor microenvironment is largely responsible for the poor efficacy of antitumor therapy, tumor relapse, and poor prognosis observed in some patients. In this review, we describe strategies that tumor cells use to respond to radiation stress, adapt, and proliferate after radiotherapy, promoting the appearance of tumor radioresistance. Also, we discuss the clinical impact of radioresistance in patient outcomes. Knowledge of such cellular strategies could help the development of new clinical interventions, increasing the radiosensitization of tumor cells, improving the effectiveness of these therapies, and increasing the survival of patients.

Role of PKM2-Mediated Immunometabolic Reprogramming on Development of Cytokine Storm

The cytokine storm is a marker of severity of various diseases and increased mortality. The altered metabolic profile and energy generation of immune cells affects their activation, exacerbating the cytokine storm. Currently, the emerging field of immunometabolism has highlighted the importance of specific metabolic pathways in immune regulation. The glycolytic enzyme pyruvate kinase M2 (PKM2) is a key regulator of immunometabolism and bridges metabolic and inflammatory dysfunction. This enzyme changes its conformation thus walks in different fields including metabolism and inflammation and associates with various transcription factors. This review summarizes the vital role of PKM2 in mediating immunometabolic reprogramming and its role in inducing cytokine storm, with a focus on providing references for further understanding of its pathological functions and for proposing new targets for the treatment of related diseases.

Oxygen and metabolic reprogramming in the tumor microenvironment influences metastasis homing

Tumor metastasis is the leading cause of cancer mortality, often characterized by abnormal cell growth and invasion to distant organs. The cancer invasion due to epithelial to mesenchymal transition is affected by metabolic and oxygen availability in the tumor-associated micro-environment. A precise alteration in oxygen and metabolic signaling between healthy and metastatic cells is a substantial probe for understanding tumor progression and metastasis. Molecular heterogeneity in the tumor microenvironment help to sustain the metastatic cell growth during their survival shift from low to high metabolic-oxygen-rich sites and reinforces the metastatic events. This review highlighted the crucial role of oxygen and metabolites in metastatic progression and exemplified the role of metabolic rewiring and oxygen availability in cancer cell adaptation. Furthermore, we have also addressed potential applications of altered oxygen and metabolic networking with tumor type that could be a signature pattern to assess tumor growth and chemotherapeutics efficacy in managing cancer metastasis.

Genetic Mutations and Non-Coding RNA-Based Epigenetic Alterations Mediating the Warburg Effect in Colorectal Carcinogenesis

Colorectal cancer (CRC) development is a gradual process defined by the accumulation of numerous genetic mutations and epigenetic alterations leading to the adenoma-carcinoma sequence. Despite significant advances in the diagnosis and treatment of CRC, it continues to be a leading cause of cancer-related deaths worldwide. Even in the presence of oxygen, CRC cells bypass oxidative phosphorylation to produce metabolites that enable them to proliferate and survive-a phenomenon known as the "Warburg effect". Understanding the complex glucose metabolism in CRC cells may support the development of new diagnostic and therapeutic approaches. Here we discuss the most recent findings on genetic mutations and epigenetic modulations that may positively or negatively regulate the Warburg effect in CRC cells. We focus on the non-coding RNA (ncRNA)-based epigenetics, and we present a perspective on the therapeutic relevance of critical molecules and ncRNAs mediating the Warburg effect in CRC cells. All the relevant studies were identified and assessed according to the genes and enzymes mediating the Warburg effect. The findings summarized in this review should provide a better understanding of the relevance of genetic mutations and the ncRNA-based epigenetic alterations to CRC pathogenesis to help overcome chemoresistance.

Mitochondrial pyruvate carrier 1 regulates ferroptosis in drug-tolerant persister head and neck cancer cells via epithelial-mesenchymal transition

Cancer cells evolve to survive as 'persister cells' resistant to various chemotherapeutic agents. Persister cancer cells retain mesenchymal traits that are vulnerable to ferroptosis by iron-dependent accumulation of lethal lipid peroxidation. Regulation of the KDM5A-MPC1 axis might shift cancer cells to have mesenchymal traits via epithelial-mesenchymal transition process. Therefore, we examined the therapeutic potentiality of KDM5A-MPC1 axis regulation in promoting ferroptosis in erlotinib-tolerant persister head and neck cancer cells (erPCC). ErPCC acquired mesenchymal traits and disabled antioxidant program that were more vulnerable to ferroptosis inducers of RSL3, ML210, sulfasalazine, and erastin. GPX4 and xCT suppression caused increased sensitivity to ferroptosis in vivo models of GPX4 genetic silencing. KDM5A expression increased and MPC1 expression decreased in erPCC. KDM5A inhibition increased MPC1 expression and decreased sensitivity to ferroptosis inducers in erPCC. MPC1 suppression increased vulnerability to ferroptosis in vitro and in vivo by retaining mesenchymal traits and glutaminolysis. Low expression of MPC1 was associated with low overall survival from the TCGA data. Our data suggest that regulation of the KDM5A-MPC1 axis contributes to promoting cancer ferroptosis susceptibility.

Fraxetin Inhibits the Proliferation and Metastasis of Glioma Cells by Inactivating JAK2/STAT3 Signaling

Glioma is the most common brain tumor and is characterized by high mortality rates, high recurrence rates, and short survival time. Migration and invasion are the basic features of gliomas. Thus, inhibition of migration and invasion may be beneficial for the treatment of patients with glioma. Due to its antitumor activity and chemical reactivity, fraxetin has attracted extensive interest and has been proven to be an effective antitumor agent in various cancer types. However, currently, the potential effects of fraxetin on glioma have not been investigated. Here, we demonstrate that fraxetin can inhibit the proliferation, invasion, and migration of glioma and induce apoptosis of glioma cells in vitro and in vivo. Therefore, these findings establish fraxetin as a drug candidate for glioma treatment. Furthermore, fraxetin was able to effectively inhibit the JAK2/STAT3 signaling in glioma. In summary, our results show that fraxetin inhibits proliferation, invasion, and migration of glioma by inhibiting JAK2/STAT3 signaling and inducing apoptosis of glioma cells. The present study provides a solid basis for the development of new glioma therapies.

The Importance of Mitochondrial Pyruvate Carrier in Cancer Cell Metabolism and Tumorigenesis

Simple Summary

The characteristic metabolic hallmark of cancer cells is the massive catabolism of glucose by glycolysis, even under aerobic conditions—the so-called Warburg effect. Although energetically unfavorable, glycolysis provides “building blocks” to sustain the unlimited growth of malignant cells. Aberrant glycolysis is also responsible for lactate accumulation and acidosis in the tumor milieu, which fosters hypoxia and immunosuppression. One of the mechanisms used by cancer cells to increase glycolytic flow is the negative regulation of the proteins that conform the mitochondrial pyruvate carrier (MPC) complex, which transports pyruvate into the mitochondrial matrix to be metabolized in the tricarboxylic acid (TCA) cycle. Evidence suggests that MPC downregulation in tumor cells impacts many aspects of tumorigenesis, including cancer cell-intrinsic (proliferation, invasiveness, stemness, resistance to therapy) and -extrinsic (angiogenesis, anti-tumor immune activity) properties. In many cancers, but not in all, MPC downregulation is associated with poor survival. MPC regulation is therefore central to tackling glycolysis in tumors.

Abstract

Pyruvate is a key molecule in the metabolic fate of mammalian cells; it is the crossroads from where metabolism proceeds either oxidatively or ends with the production of lactic acid. Pyruvate metabolism is regulated by many enzymes that together control carbon flux. Mitochondrial pyruvate carrier (MPC) is responsible for importing pyruvate from the cytosol to the mitochondrial matrix, where it is oxidatively phosphorylated to produce adenosine triphosphate (ATP) and to generate intermediates used in multiple biosynthetic pathways. MPC activity has an important role in glucose homeostasis, and its alteration is associated with diabetes, heart failure, and neurodegeneration. In cancer, however, controversy surrounds MPC function. In some cancers, MPC upregulation appears to be associated with a poor prognosis. However, most transformed cells undergo a switch from oxidative to glycolytic metabolism, the so-called Warburg effect, which, amongst other possibilities, is induced by MPC malfunction or downregulation. Consequently, impaired MPC function might induce tumors with strong proliferative, migratory, and invasive capabilities. Moreover, glycolytic cancer cells secrete lactate, acidifying the microenvironment, which in turn induces angiogenesis, immunosuppression, and the expansion of stromal cell populations supporting tumor growth. This review examines the latest findings regarding the tumorigenic processes affected by MPC.

Taurine rescues mitochondria-related metabolic impairments in the patient-derived induced pluripotent stem cells and epithelial-mesenchymal transition in the retinal pigment epithelium

Mitochondria participate in various metabolic pathways, and their dysregulation results in multiple disorders, including aging-related diseases. However, the metabolic changes and mechanisms of mitochondrial disorders are not fully understood. Here, we found that induced pluripotent stem cells (iPSCs) from a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) showed attenuated proliferation and survival when glycolysis was inhibited. These deficits were rescued by taurine administration. Metabolomic analyses showed that the ratio of the reduced (GSH) to oxidized glutathione (GSSG) was decreased; whereas the levels of cysteine, a substrate of GSH, and oxidative stress markers were upregulated in MELAS iPSCs. Taurine normalized these changes, suggesting that MELAS iPSCs were affected by the oxidative stress and taurine reduced its influence. We also analyzed the retinal pigment epithelium (RPE) differentiated from MELAS iPSCs by using a three-dimensional culture system and found that it showed epithelial mesenchymal transition (EMT), which was suppressed by taurine. Therefore, mitochondrial dysfunction caused metabolic changes, accumulation of oxidative stress that depleted GSH, and EMT in the RPE that could be involved in retinal pathogenesis. Because all these phenomena were sensitive to taurine treatment, we conclude that administration of taurine may be a potential new therapeutic approach for mitochondria-related retinal diseases.

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iPS cell lines were derived from a MELAS patient with the mtDNA A3243G mutation.

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Decreased proliferation and survival of MELAS iPSCs were rescued by taurine.

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Reduction in GSH/GSSG ratio in MELAS iPSCs was suppressed by taurine.

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EMT in MELAS iPSC-derived retinal pigment epithelium was suppressed by taurine.

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Oxidative stress markers in MELAS iPSCs and RPE were suppressed by taurine.

Targeting Glutaminolysis: New Perspectives to Understand Cancer Development and Novel Strategies for Potential Target Therapies

Metabolism rewiring is an important hallmark of cancers. Being one of the most abundant free amino acids in the human blood, glutamine supports bioenergetics and biosynthesis, tumor growth, and the production of antioxidants through glutaminolysis in cancers. In glutamine dependent cancer cells, more than half of the tricarboxylic/critic acid (TCA) metabolites are derived from glutamine. Glutaminolysis controls the process of converting glutamine into TCA cycle metabolites through the regulation of multiple enzymes, among which the glutaminase shows the importance as the very first step in this process. Targeting glutaminolysis via glutaminase inhibition emerges as a promising strategy to disrupt cancer metabolism and tumor progression. Here, we review the regulation of glutaminase and the role of glutaminase in cancer metabolism and metastasis. Furthermore, we highlight the glutaminase inhibitor based metabolic therapy strategy and their potential applications in clinical scenarios.

Mitochondrial Pyruvate Carrier Function in Health and Disease across the Lifespan

As a nodal mediator of pyruvate metabolism, the mitochondrial pyruvate carrier (MPC) plays a pivotal role in many physiological and pathological processes across the human lifespan, from embryonic development to aging-associated neurodegeneration. Emerging research highlights the importance of the MPC in diverse conditions, such as immune cell activation, cancer cell stemness, and dopamine production in Parkinson’s disease models. Whether MPC function ameliorates or contributes to disease is highly specific to tissue and cell type. Cell- and tissue-specific differences in MPC content and activity suggest that MPC function is tightly regulated as a mechanism of metabolic, cellular, and organismal control. Accordingly, recent studies on cancer and diabetes have identified protein–protein interactions, post-translational processes, and transcriptional factors that modulate MPC function. This growing body of literature demonstrates that the MPC and other mitochondrial carriers comprise a versatile and dynamic network undergirding the metabolism of health and disease.

Membrane Transporters and Channels in Melanoma

Recent research has revealed that ion channels and transporters can be important players in tumor development, progression, and therapy resistance in melanoma. For example, members of the ABC family were shown to support cancer stemness-like features in melanoma cells, while several members of the TRP channel family were reported to act as tumor suppressors.Also, many transporter proteins support tumor cell viability and thus suppress apoptosis induction by anticancer therapy. Due to the high number of ion channels and transporters and the resulting high complexity of the field, progress in understanding is often focused on single molecules and is in total rather slow. In this review, we aim at giving an overview about a broad subset of ion transporters, also illustrating some aspects of the field, which have not been addressed in detail in melanoma. In context with the other chapters in this special issue on "Transportome Malfunctions in the Cancer Spectrum," a comparison between melanoma and these tumors will be possible.

The Multifaceted Pyruvate Metabolism: Role of the Mitochondrial Pyruvate Carrier

Pyruvate, the end product of glycolysis, plays a major role in cell metabolism. Produced in the cytosol, it is oxidized in the mitochondria where it fuels the citric acid cycle and boosts oxidative phosphorylation. Its sole entry point into mitochondria is through the recently identified mitochondrial pyruvate carrier (MPC). In this review, we report the latest findings on the physiology of the MPC and we discuss how a dysfunctional MPC can lead to diverse pathologies, including neurodegenerative diseases, metabolic disorders, and cancer.

Characteristic Analysis of Homo- and Heterodimeric Complexes of Human Mitochondrial Pyruvate Carrier Related to Metabolic Diseases

Human mitochondrial pyruvate carriers (hMPCs), which are required for the uptake of pyruvate into mitochondria, are associated with several metabolic diseases, including type 2 diabetes and various cancers. Yeast MPC was recently demonstrated to form a functional unit of heterodimers. However, human MPC-1 (hMPC-1) and MPC-2 (hMPC-2) have not yet been individually isolated for their detailed characterization, in particular in terms of their structural and functional properties, namely, whether they exist as homo- or heterodimers. In this study, hMPC-1 and hMPC-2 were successfully isolated in micelles and they formed stable homodimers. However, the heterodimer state was found to be dominant when both hMPC-1 and hMPC-2 were present. In addition, as heterodimers, the molecules exhibited a higher binding capacity to both substrates and inhibitors, together with a larger structural stability than when they existed as homodimers. Taken together, our results demonstrated that the hetero-dimerization of hMPCs is the main functional unit of the pyruvate metabolism, providing a structural insight into the transport mechanisms of hMPCs.

A comparative pharmaco-metabolomic study of glutaminase inhibitors in glioma stem-like cells confirms biological effectiveness but reveals differences in target-specificity

Cancer cells upregulate anabolic processes to maintain high rates of cellular turnover. Limiting the supply of macromolecular precursors by targeting enzymes involved in biosynthesis is a promising strategy in cancer therapy. Several tumors excessively metabolize glutamine to generate precursors for nonessential amino acids, nucleotides, and lipids, in a process called glutaminolysis. Here we show that pharmacological inhibition of glutaminase (GLS) eradicates glioblastoma stem-like cells (GSCs), a small cell subpopulation in glioblastoma (GBM) responsible for therapy resistance and tumor recurrence. Treatment with small molecule inhibitors compound 968 and CB839 effectively diminished cell growth and in vitro clonogenicity of GSC neurosphere cultures. However, our pharmaco-metabolic studies revealed that only CB839 inhibited GLS enzymatic activity thereby limiting the influx of glutamine derivates into the TCA cycle. Nevertheless, the effects of both inhibitors were highly GLS specific, since treatment sensitivity markedly correlated with GLS protein expression. Strikingly, we found GLS overexpressed in in vitro GSC models as compared with neural stem cells (NSC). Moreover, our study demonstrates the usefulness of in vitro pharmaco-metabolomics to score target specificity of compounds thereby refining drug development and risk assessment.

A novel KDM5A/MPC-1 signaling pathway promotes pancreatic cancer progression via redirecting mitochondrial pyruvate metabolism

Mitochondrial pyruvate carrier 1 (MPC-1) appears to be a tumor suppressor. In this study, we determined the regulation of MPC-1 expression by Lysine demethylase 5A (KDM5A) and critical impact of this novel KDM5A/MPC-1 signaling on PDA progression. TCGA database, paired PDA and adjacent normal pancreatic tissues, PDA tissue array and cell lines were used to determine the levels of MPC-1 and KDM5A expression, and their relationship with the clinicopathologic characteristics and overall survival (OS) of PDA patients. Both in vitro and in vivo models were used to determine biologic impacts of MPC-1 and KDM5A on PDA and mitochondrial pyruvate metabolism, and the mechanism underling reduced MPC-1 expression in PDA. The expression of MPC-1 was decreased in PDA cell lines and tissues, and negatively associated with tumor poorer differentiation, lymph nodes metastasis, higher TNM stages, and patients' overall survival (OS). Functional analysis revealed that restored expression of MPC-1 suppressed the growth, invasion, migration, stemness and tumorigenicity. Re-expression of MPC-1 stimulated the mitochondrial pyruvate metabolism and inhibited glycolysis, while MPC-1-specific inhibitor UK5099 attenuated these effects. Furthermore, KDM5A bound directly to MPC-1 promoter region and transcriptionally suppressed the expression of MPC-1 via demethylation H3K4. Consistently, KDM5A expression was elevated in PDA and promoted PDA cell proliferation in vitro and tumor growth in vivo via suppressing the expression of MPC-1. The expression of KDM5A was inversely correlated with that of MPC-1 in PDA. KDM5A/MPC-1 signaling promoted PDA growth, invasion, migration, and stemness via inhibiting mitochondrial pyruvate metabolism. Targeting KDM5A/MPC-1 signaling may be an effective therapeutic strategy for PDA.

Targeting the Mitochondrial Pyruvate Carrier for Neuroprotection

The mitochondrial pyruvate carriers mediate pyruvate import into the mitochondria, which is key to the sustenance of the tricarboxylic cycle and oxidative phosphorylation. However, inhibition of mitochondria pyruvate carrier-mediated pyruvate transport was recently shown to be beneficial in experimental models of neurotoxicity pertaining to the context of Parkinson's disease, and is also protective against excitotoxic neuronal death. These findings attested to the metabolic adaptability of neurons resulting from MPC inhibition, a phenomenon that has also been shown in other tissue types. In this short review, I discuss the mechanism and potential feasibility of mitochondrial pyruvate carrier inhibition as a neuroprotective strategy in neuronal injury and neurodegenerative diseases.

Mitochondrial pyruvate carrier 1 expression controls cancer epithelial-mesenchymal transition and radioresistance

Mitochondrial pyruvate carrier (MPC) is known to cause different expressions in normal and cancer cells. We observed a change in phenotype with the suppression of MPC expression. We knocked down MPC1 and/or MPC2 using siRNA or shRNA. We observed its cell morphology and accompanying molecular marker. Furthermore, the radioresistance of the MPC knockdown cell line was examined using a colony formation assay. MPC1‐suppressed cells changed their morphology to a spindle shape. Epithelial‐mesenchymal transition (EMT) was suspected, and examination of the EMT marker by PCR showed a decrease in E‐cadherin and an increase in fibronectin. Focusing on glutamine metabolism as the mechanism of this phenomenon, we knocked down the glutamine‐metabolizing enzyme glutaminase (GLS). EMT was also observed in GLS‐suppressed cells. Furthermore, when MPC1‐suppressed cells were cultured in a glutamine‐deficient medium, changes in EMT markers were suppressed. In addition, MPC1‐suppressed cells also increased with a significant difference in radioresistance. Decreased MPC1 expression favorably affects EMT and radioresistance of cancer.