Is Akt the "Warburg kinase"?-Akt-energy metabolism interactions and oncogenesis

Citrate oscillations during cell cycle are a targetable vulnerability in cancer cells

Cell cycle progression is timely interconnected with oscillations in cellular metabolism. Here, we first describe how these metabolic oscillations allow cycling cells to meet the bioenergetic needs specifically for each phase of the cell cycle. In parallel, we highlight how the cytosolic level of citrate is dynamically regulated during these different phases, being low in G1 phase, increasing in S phase, peaking in G2/M, and decreasing in mitosis. Of note, in cancer cells, a dysregulation of such citrate oscillation can support cell cycle progression by promoting a deregulated Warburg effect (aerobic glycolysis), activating oncogenic signaling pathways (such as PI3K/AKT), and promoting acetyl-CoA production via alternative routes, such as overconsumption of acetate. Then, we review how administration of sodium citrate (at high doses) arrests the cell cycle in G0/G1 or G2/M, inhibits glycolysis and PI3K/AKT, induces apoptosis, and significantly reduces tumor growth in various in vivo models. Last, we reason on the possibility to implement citrate administration to reinforce the effectiveness of cell cycle inhibitors to better cure cancer.

Deciphering the roles of neddylation modification in hepatocellular carcinoma: Molecular mechanisms and targeted therapeutics

Hepatocellular carcinoma (HCC) is the most prevalent type of malignant liver tumor with high morbidity and mortality and severely threatens human health and life quality. Thus, it is of great significance to investigate the molecular mechanism underlying the pathogenesis of HCC and seek biomarkers for early diagnosis. Neddylation, one of the most conserved post-translational modification types in eukaryotes, plays vital roles in the progression of HCC. During the process of neddylation, NEDD8 is covalently conjugated to its substrate proteins, thereby modulating multiple necessary biological processes. Currently, increasing evidence shows that the aberrant activation of neddylation is positively correlated with the occurrence and development of tumors and the poor clinical prognosis of HCC patients. Based on the current investigations, neddylation modification has been reported to target both the cullins and non-cullin substrates and subsequently affect HCC progression, including the virus infection, malignant transformation, tumor cell proliferation, migration and invasion ability, and tumor microenvironment. Therefore, inhibitors targeting the neddylation cascade have been developed and entered clinical trials, indicating satisfactory anti-HCC treatment effects. This review aims to summarize the latest progress in the molecular mechanism of pathologically aberrant neddylation in HCC, as well as the advances of neddylation-targeted inhibitors as potential drugs for HCC treatment.

Mechanisms of muscle repair after peripheral nerve injury by electrical stimulation combined with blood flow restriction training

This review elucidates the impact of electrical stimulation (ES) and blood flow restriction (BFR) training on muscle function. ES induces a transformation in muscle fibers type by rearranging myosin heavy chain isoform patterns. Additionally, it influences muscle protein synthesis and degradation through specific signaling pathways such as protein kinase B/mechanistic target of rapamycin (Akt/mTOR), as well as via autophagy and the ubiquitin-proteasome system, thereby effectively maintaining muscle mass. BFR, on the other hand, restricts muscle blood flow, leading to metabolic products accumulation and localized hypoxia, which not only promotes the recruitment of fast-twitch fibers but also activates the mTOR signaling pathway, enhancing muscle protein synthesis. The combination of ES and BFR synergistically facilitates muscle protein synthesis through the mTOR pathway, thereby accelerating the recovery of muscle function following peripheral nerve injury.

Novel Phenoxyacetic Acid (4-Aminophenoacetic Acid) Shikonin Ester Kills KRAS Mutant Colon Cancer Cells via Targeting the Akt Allosteric Site

The PI3K-Akt axis is abnormally activated in KRAS-mutated colorectal cancer and is considered to be a potential therapeutic target. A novel series of phenoxyacetic acid (4-aminophenoacetic acid) shikonin esters was designed by computer-aided drug design (CADD) and synthesized as Akt allosteric inhibitors. Most compounds exhibited greater anti-proliferative activity compared to the positive control MK2206, while also demonstrating lower cytotoxicity against normal cells than shikonin. One of the promising candidates, L8, was selected for further biological evaluation. Docking studies indicated that L8 effectively bound to the allosteric site of Akt through hydrophobic and hydrogen interactions. Enzyme activity and kinetics assessments revealed that L8 bound to Akt with a Kd of 2.07 × 10-6 M and inhibited its activity. Further intracellular assays, including western blotting, enzyme activity assay, flow cytometry, etc., verified that L8 mediated the death of two KRAS-mutant colon cancer cell lines HCT116 (KRASG13D) and HCT-8 (KRASG12A) cells by inactivating Akt, causing tumor cell apoptosis, cell cycle arrest, and interfering with tumor cell invasion and metabolism. A 3D-QSAR model was constructed to understand the relationship between the structure of the shikonin derivatives and their anti-proliferative activity. The in silico ADMET and toxicity prediction studies revealed a few undesired pharmacokinetic attributes of our compounds.

Exploring the metabolic alterations in cervical cancer induced by HPV oncoproteins: From mechanisms to therapeutic targets

The role of human Papillomavirus (HPV) in metabolic reprogramming is implicated in the development and progression of cervical cancer. During carcinogenesis, cancer cells modify various metabolic pathways to generate energy and sustain their growth and development. Cervical cancer, one of the most prevalent malignancies affecting women globally, involves metabolic alterations such as increased glycolysis, elevated lactate production, and lipid accumulation. The oncoproteins, primarily E6 and E7, which are encoded by high-risk HPVs, facilitate the accumulation of several cancer markers, promoting not only the growth and development of cancer but also metastasis, immune evasion, and therapy resistance. HPV oncoproteins interact with cellular MYC (c-MYC), retinoblastoma protein (pRB), p53, and hypoxia-inducible factor 1α (HIF-1α), leading to the induction of metabolic reprogramming and favour the Warburg effect. Metabolic reprogramming enables HPV to persist for an extended period and accelerates the progression of cervical cancer. This review summarizes the role of HPV oncoproteins in metabolic reprogramming and their contributions to the development and progression of cervical cancer. Additionally, this review provides insights into how metabolic reprogramming opens avenues for novel therapeutic strategies, including the discovery of new and repurposed drugs that could be applied to treat cervical cancer.

TMEM45A enhances palbociclib resistance and cellular glycolysis by activating AKT/mTOR signaling pathway in HR+ breast cancer

Palbociclib, a CDK4/6 inhibitor, plays a crucial role in the treatment of HR+ breast cancer. However, resistance to palbociclib is a significant concern that merits further investigation. Our investigation identifies TMEM45A as a potential driver of palbociclib resistance and its association with increased cellular glycolysis. We demonstrate that TMEM45A is highly expressed in palbociclib-resistant breast cancer (BRCA) cells, correlating with enhanced tumor progression. Silencing TMEM45A enhances sensitivity to palbociclib, promotes cell cycle arrest and apoptosis, and inhibits the proliferation of BRCA cells. Moreover, attenuation of TMEM45A expression reduces cancer aggressiveness by decreasing the expression of EMT and glycolysis-related proteins. Subsequent gene set enrichment analysis (GSEA) confirms that TMEM45A activates the AKT/mTOR signaling pathway, which is integral to cell cycle progression and glycolysis. In a cell line-derived xenograft (CDX) mouse model, TMEM45A knockdown significantly restores sensitivity to palbociclib and suppresses tumor growth. Additionally, the use of engineered exosomes loaded with siRNA targeting TMEM45A presents a promising strategy for enhancing CDK4/6 inhibitor sensitivity without observable toxic side effects in a patient-derived xenograft (PDX) model. Collectively, our findings suggest that TMEM45A may be a therapeutic target for overcoming palbociclib resistance, and exosomal siRNA delivery could be a viable strategy for precision medicine in HR+ breast cancer.

The role of lncRNAs in the interplay of signaling pathways and epigenetic mechanisms in glioma

Gliomas, highly aggressive tumors of the central nervous system, present overwhelming challenges due to their heterogeneity and therapeutic resistance. Glioblastoma multiforme (GBM), the most malignant form, underscores this clinical urgency due to dismal prognosis despite aggressive treatment regimens. Recent advances in cancer research revealed signaling pathways and epigenetic mechanisms that intricately govern glioma progression, offering multifaceted targets for therapeutic intervention. This review explores the dynamic interplay between signaling events and epigenetic regulation in the context of glioma, with a particular focus on the crucial roles played by non-coding RNAs (ncRNAs). Through direct and indirect epigenetic targeting, ncRNAs emerge as key regulators shaping the molecular landscape of glioblastoma across its various stages. By dissecting these intricate regulatory networks, novel and patient-tailored therapeutic strategies could be devised to improve patient outcomes with this devastating disease.

A Phase I Study of the Pharmacokinetics and Safety of Ipatasertib, an Akt Inhibitor in Chinese Patients With Locally Advanced or Metastatic Solid Tumors

PURPOSE

Ipatasertib is a selective inhibitor of Akt, a frequently activated protein kinase that plays a critical role in human cancers. The current clinical trial aimed to assess the pharmacokinetic properties, safety, and tolerability of ipatasertib administered to Chinese patients with locally advanced or metastatic solid tumors.

METHODS

A Phase I, single-arm, open-label study was performed in Chinese patients with locally advanced or metastatic solid tumors for whom standard therapy either does not exist or has proven ineffective. Four hundred milligrams of ipatasertib was administered to patients as a single agent, starting with a single dose for 7 days and continuous daily dosing for 21 days, followed by 7 days off schedule. The pharmacokinetic properties of ipatasertib and its major metabolite M1 (GO37220) after single and multiple dose administration were assessed using a validated liquid chromatography-tandem mass spectrometry assay method. Safety was assessed throughout the study, and adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. Tumor response was assessed by the investigator using Response Evaluation Criteria in Solid Tumors version 1.1.

FINDINGS

Fourteen patients were enrolled, and all enrolled patients received at least 1 dose of the study treatment. Ipatasertib and M1 exposures were slightly higher than previously reported but comparable with exposures observed within the Asian population. Ipatasertib as a single agent demonstrated a manageable safety profile in Chinese patients, which is aligned with prior observation in global studies. Limited efficacy was observed in these patients with heavily pretreated diverse solid tumors.

IMPLICATIONS

This study of the pharmacokinetic properties, safety, and efficacy of ipatasertib in Chinese patients eventually contributed toward the development of Akt inhibitors in China.

CLINICALTRIALS

gov identifier: NCT04341259.

Why and how citrate may sensitize malignant tumors to immunotherapy

Immunotherapy, either alone or in combination with chemotherapy, has demonstrated limited efficacy in a variety of solid cancers. Several factors contribute to explaining primary or secondary resistance. Among them, cancer cells, whose metabolism frequently relies on aerobic glycolysis, promote exhaustion of cytotoxic immune cells by diverting the glucose in the tumor microenvironment (TME) to their own profit, while secreting lactic acid that sustains the oxidative metabolism of immunosuppressive cells. Here, we propose to combine current treatment based on the use of immune checkpoint inhibitors (ICIs) with high doses of sodium citrate (SCT) because citrate inhibits cancer cell metabolism (by targeting both glycolysis and oxidative metabolism) and may active anti-tumor immune response. Indeed, as showed in preclinical studies, SCT reduces cancer cell growth, promoting cell death and chemotherapy effectiveness. Furthermore, since the plasma membrane citrate carrier pmCIC is mainly expressed in cancer cells and low or not expressed in immune and non-transformed cells, we argue that the inhibition of cancer cell metabolism by SCT may increase glucose availability in the TME, thus promoting functionality of anti-tumor immune cells. Concomitantly, the decrease in the amount of lactic acid in the TME may reduce the functionality of immunosuppressive cells. Preclinical studies have shown that SCT can enhance the anti-tumor immune response through an enhancement of T cell infiltration and activation, and a repolarization of macrophages towards a TAM1-like phenotype. Therefore, this simple and cheap strategy may have a major impact to increase the efficacy of current immunotherapies in human solid tumors and we encourage testing it in clinical trials.

AKT and the Hallmarks of Cancer

Nearly a quarter century ago, Hanahan and Weinberg conceived six unifying principles explaining how normal cells transform into malignant tumors. Their provisional set of biological capabilities acquired during tumor development-cancer hallmarks-would evolve to 14 tenets as knowledge of cancer genomes, molecular mechanisms, and the tumor microenvironment expanded, most recently adding four emerging enabling characteristics: phenotypic plasticity, epigenetic reprogramming, polymorphic microbiomes, and senescent cells. AKT kinases are critical signaling molecules that regulate cellular physiology upon receptor tyrosine kinases and PI3K activation. The complex branching of the AKT signaling network involves several critical downstream nodes that significantly magnify its functional impact, such that nearly every organ system and cell in the body may be affected by AKT activity. Conversely, tumor-intrinsic dysregulation of AKT can have numerous adverse cellular and pathologic ramifications, particularly in oncogenesis, as multiple tumor suppressors and oncogenic proteins regulate AKT signaling. Herein, we review the mounting evidence implicating the AKT pathway in the aggregate of currently recognized hallmarks of cancer underlying the complexities of human malignant diseases. The challenges, recent successes, and likely areas for exciting future advances in targeting this complex pathway are also discussed.

YAP1 Overexpression Enhances the Aerobic Glycolysis Process via Suppression of EGLN2 in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases and has remarkably high mortality rates. In recent years, altered metabolism has been shown to contribute to the maintenance of pancreatic cancer malignancies. However, the molecular mechanism underlying glucose metabolism reprogramming remains elusive. The aim of this study was to elucidate the role of Yes-associated protein (YAP1), an important effector of the Hippo pathway, in the regulation of aerobic glycolysis in pancreatic cancer. Moreover, the contributions of YAP1 and its associated glycolytic enzymes to prognosis were assessed via The Cancer Genome Atlas (TCGA) dataset.

METHODS

YAP1 expression was silenced by short hairpin RNA (shRNA), and its effects on glycolytic activity and mitochondrial respiration were analysed via Agilent Seahorse XF Analysers. The effects of YAP1 on hypoxia-inducible factor-1α (HIF-1α) and its transcriptional activity on glycolytic genes were examined via shRNA-mediated silencing of YAP1. The underlying mechanism by which YAP1 controls the HIF-1α protein level was analysed by exploring the interaction between YAP1 and egg-laying-defective nine family (EGLN) members, which are well-established regulators of the HIF-1α protein level. Finally, the effects of YAP1, EGLN and glycolytic genes on prognosis were analysed via TCGA dataset.

RESULTS

We found that silencing YAP1 expression inhibited anabolic glycolysis in pancreatic cancer cells. YAP1 was demonstrated to regulate the HIF-1α protein level, transcriptional activity and the expression of HIF-1α-targeted glycolytic genes. In-depth analysis demonstrated that EGLN2, a modulator of the HIF-1α protein level, was a direct target of YAP1. Low EGLN2 expression was associated with a poor prognosis. By analysing TCGA dataset and performing immunohistochemical staining, we demonstrated that YAP1 expression was negatively correlated with EGLN2 expression at the mRNA level and protein levels.

CONCLUSIONS

The present study demonstrated that YAP1 positively regulates aerobic glycolysis by inhibiting EGLN2 expression, which results in an increased HIF-1α protein level and transcriptional activity. YAP1 was positively regulated and significantly correlated with HIF-1α-targeted glycolytic genes, including glucose transporter type 1(GLUT1), hexokinase2 (HK2) and lactate dehydrogenase A (LDHA). Elevated YAP1 expression and concomitant downregulation of EGLN2 contributed to poor survival in patients with pancreatic cancer. Our results suggest that YAP1 may be a promising predictive marker and treatment target for human pancreatic cancer.

Tripartite-motif 3 represses ovarian cancer progression by downregulating lactate dehydrogenase A and inhibiting AKT signaling

The E3 ubiquitin ligase Tripartite-motif 3 (TRIM3) is known to play a crucial role in tumor suppression in various tumors through different mechanisms. However, its function and mechanism in ovarian cancer have yet to be elucidated. Our study aims to investigate the expression of TRIM3 in ovarian cancer and evaluate its role in the development of the disease. Our findings revealed a significant decrease in TRIM3 mRNA and protein levels in ovarian cancer tissues and cells when compared to normal ovarian epithelial tissues and cells. Furthermore, we observed a negative correlation between the protein level of TRIM3 and the FIGO stage, as well as a positive correlation with the survival of ovarian cancer patients. Using gain and loss of function experiments, we demonstrated that TRIM3 can inhibit cell proliferation, migration and invasion of the ovarian cancer cells in vitro, as well as suppress tumor growth in vivo. Mechanistic studies showed that TRIM3 interacts with lactate dehydrogenase A, a key enzyme in the glycolytic pathway, through its B-box and coiled-coil domains and induces its ubiquitination and proteasomal degradation, leading to the inhibition of glycolytic ability in ovarian cancer cells. RNA-sequencing analysis revealed significant alterations in the phosphatidylinositol signaling pathways upon TRIM3 overexpression. Additionally, overexpression of TRIM3 inhibited the phosphorylation of AKT. In conclusion, our study demonstrated that TRIM3 exerts a tumor-suppressive effect in ovarian cancer, at least partially, by downregulating LDHA and inhibiting the AKT signaling pathway, and thus leading to the inhibition of glycolysis and limiting the growth of ovarian cancer cells.

Extra-nuclear TERT counteracts oxidative stress and promotes progression in papillary thyroid carcinoma

The reactivation of TERT is associated with poor outcome in papillary thyroid cancer (PTC). Extra-telomeric functions of TERT were reported, with a protective role against oxidative stress (OS). The aim of the present study was to explore the extra-nuclear TERT localization in PTC and its role in cancer progression. TERT nuclear export under OS were analyzed in K1 PTC cell line. We investigated the role of different TERT localizations using specific TERT constructs that limit its localization to the nucleus or to the mitochondria. The effect of SRC kinase inhibitor PP2, which reduces TERT nuclear export, was investigated as well. Moreover, TERT localization was analyzed in 39 PTC tissues and correlated with the genetic profile and the level of OS, DNA damage and apoptosis in the tumors and with the clinical characteristics of the patients. We demonstrated that TERT is exported from the nucleus in response to OS induced either from H2O2 or the BRAF inhibitor PLX4720. We proved that extra-nuclear TERT reduces mitochondrial OS and induces mitochondrial fragmentation. Moreover, limiting mitochondrial TERT localization reduced proliferation, migration, AKT phosphorylation and glycolysis and increased DNA damage and p21 expression. Finally, in PTC tissues the fraction of mitochondrial/nuclear TERT resulted inversely correlated with OS and p21 expression and associated with tumor persistence. In conclusion, our data indicate that extra-nuclear TERT is involved in reducing the effect of excessive OS, thus promoting cancer cell survival. Extra-nuclear TERT may thus represent a marker of cancer progression and a possible therapeutic target in PTC.

Evaluation of the effect of GSK-3β on liver cancer based on the PI3K/AKT pathway

The PI3K/AKT/GSK-3β signaling pathway plays a pivotal role in numerous physiological and pathological processes, including cell proliferation, apoptosis, differentiation, and metabolic regulation. Aberrant activation of the PI3K/AKT pathway is intricately linked to development of tumor. GSK-3β, belonging to the serine/threonine protein kinase family, is crucial in the pathogenesis of liver cancer. As a key rate-limiting enzyme in the glucose metabolism pathway, GSK-3β significantly impacts the growth, proliferation, metastasis, and apoptosis of liver cancer cells. It is also implicated in chemotherapy resistance. Elevated expression of GSK-3β diminishes the sensitivity of liver cancer cells to chemotherapeutic agents, thereby playing a substantial role in the development of drug resistance. Consequently, targeting of GSK-3β, particularly within the PI3K/AKT signaling pathway, is regarded as a promising therapeutic strategy for liver cancer. The precise identification and subsequent modulation of this pathway represent a substantial potential for innovative clinical interventions in the management of liver cancer.

MRTO4 Enhances Glycolysis to Facilitate HCC Progression by Inhibiting ALDOB

BACKGROUND MRT4 Homolog, Ribosome Maturation Factor (MRTO4) is often upregulated in cancer cells. However, its impact in hepatocellular carcinoma (HCC) is less well understood. Herein, we explored the prognostic and energy metabolism reprogramming role of MRTO4 in HCC. MATERIAL AND METHODS Clinical data were obtained from The Cancer Genome Atlas (TCGA), and the expression of MRTO4 in clinical samples was analyzed. The association between different variables and overall survival (OS) was studied, as well as their potential as independent prognostic factors, using Cox regression analysis. We constructed a nomogram including clinical pathological variables and MRTO4 expression to provide a predictive model for prognosis. Heatmaps, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed the relationship between energy metabolism pathways and MRTO4. We used classic molecular biology research methods, including RT-qPCR, Western blotting, CCK8, TUNEL, Clone formation, Transwell assay, ELISA, and immunohistochemistry, to study the role of MRTO4 in promoting the progression of HCC through glycolysis regulation. RESULTS Our study showed that MRTO4 is an independent prognostic risk factor for HCC and that MRTO4 accelerates glycolysis of HCC cells, promotes proliferation and invasion, and suppresses apoptosis of HCC cells. The underlying mechanism involves MRTO4 promoting glycolysis and accelerating HCC by inhibiting ALDOB. CONCLUSIONS Our study revealed a novel mechanism by which MRTO4 promotes glycolysis and accelerates HCC progression, and suggests that inhibiting MRTO4 could be a potential therapeutic strategy for HCC.

Lactate and lactylation in macrophage metabolic reprogramming: current progress and outstanding issues

It is commonly known that different macrophage phenotypes play specific roles in different pathophysiological processes. In recent years, many studies have linked the phenotypes of macrophages to their characteristics in different metabolic pathways, suggesting that macrophages can perform different functions through metabolic reprogramming. It is now gradually recognized that lactate, previously overlooked as a byproduct of glycolytic metabolism, acts as a signaling molecule in regulating multiple biological processes, including immunological responses and metabolism. Recently, lactate has been found to mediate epigenetic changes in macrophages through a newfound lactylation modification, thereby regulating their phenotypic transformation. This novel finding highlights the significant role of lactate metabolism in macrophage function. In this review, we summarize the features of relevant metabolic reprogramming in macrophages and the role of lactate metabolism therein. We also review the progress of research on the regulation of macrophage metabolic reprogramming by lactylation through epigenetic mechanisms.

Pattern-Recognition Receptors and Immunometabolic Reprogramming: What We Know and What to Explore

BACKGROUND

Evolutionarily, immune response is a complex mechanism that protects the host from internal and external threats. Pattern-recognition receptors (PRRs) recognize MAMPs, PAMPs, and DAMPs to initiate a protective pro-inflammatory immune response. PRRs are expressed on the cell membranes by TLR1, 2, 4, and 6 and in the cytosolic organelles by TLR3, 7, 8, and 9, NLRs, ALRs, and cGLRs. We know their downstream signaling pathways controlling immunoregulatory and pro-inflammatory immune response. However, the impact of PRRs on metabolic control of immune cells to control their pro- and anti-inflammatory activity has not been discussed extensively.

SUMMARY

Immune cell metabolism or immunometabolism critically determines immune cells' pro-inflammatory phenotype and function. The current article discusses immunometabolic reprogramming (IR) upon activation of different PRRs, such as TLRs, NLRs, cGLRs, and RLRs. The duration and type of PRR activated, species studied, and location of immune cells to specific organ are critical factors to determine the IR-induced immune response.

KEY MESSAGE

The work herein describes IR upon TLR, NLR, cGLR, and RLR activation. Understanding IR upon activating different PRRs is critical for designing better immune cell-specific immunotherapeutics and immunomodulators targeting inflammation and inflammatory diseases.

GLUT and HK: Two primary and essential key players in tumor glycolysis

Cancer cells reprogram their metabolism to become "glycolysis-dominant," which enables them to meet their energy and macromolecule needs and enhancing their rate of survival. This glycolytic-dominancy is known as the "Warburg effect", a significant factor in the growth and invasion of malignant tumors. Many studies confirmed that members of the GLUT family, specifically HK-II from the HK family play a pivotal role in the Warburg effect, and are closely associated with glucose transportation followed by glucose metabolism in cancer cells. Overexpression of GLUTs and HK-II correlates with aggressive tumor behaviour and tumor microenvironment making them attractive therapeutic targets. Several studies have proven that the regulation of GLUTs and HK-II expression improves the treatment outcome for various tumors. Therefore, small molecule inhibitors targeting GLUT and HK-II show promise in sensitizing cancer cells to treatment, either alone or in combination with existing therapies including chemotherapy, radiotherapy, immunotherapy, and photodynamic therapy. Despite existing therapies, viable methods to target the glycolysis of cancer cells are currently lacking to increase the effectiveness of cancer treatment. This review explores the current understanding of GLUT and HK-II in cancer metabolism, recent inhibitor developments, and strategies for future drug development, offering insights into improving cancer treatment efficacy.

Metabolic Adaptations and Functional Activity of Macrophages in Homeostasis and Inflammation

In recent years, the role of cellular metabolism in immunity has come into the focus of many studies. These processes form a basis for the maintenance of tissue integrity and homeostasis, as well as represent an integral part of the immune response, in particular, inflammation. Metabolic adaptations not only ensure energy supply for immune response, but also affect the functions of immune cells by controlling transcriptional and post-transcriptional programs. Studying the immune cell metabolism facilitates the search for new treatment approaches, especially for metabolic disorders. Macrophages, innate immune cells, are characterized by a high functional plasticity and play a key role in homeostasis and inflammation. Depending on the phenotype and origin, they can either perform various regulatory functions or promote inflammation state, thus exacerbating the pathological condition. Furthermore, their adaptations to the tissue-specific microenvironment influence the intensity and type of immune response. The review examines the effect of metabolic reprogramming in macrophages on the functional activity of these cells and their polarization. The role of immunometabolic adaptations of myeloid cells in tissue homeostasis and in various pathological processes in the context of inflammatory and metabolic diseases is specifically discussed. Finally, modulation of the macrophage metabolism-related mechanisms reviewed as a potential therapeutic approach.

Related mechanisms, current treatments, and new perspectives in meningioma

Meningiomas are non-glial tumors that are the most common primary brain tumors in adults. Although meningioma can possibly be cured with surgical excision, variations in atypical/anaplastic meningioma have a high recurrence rate and a poor prognosis. As a result, it is critical to develop novel therapeutic options for high-grade meningiomas. This review highlights the current histology of meningiomas, prevalent genetic and molecular changes, and the most extensively researched signaling pathways and therapies in meningiomas. It also reviews current clinical studies and novel meningioma treatments, including immunotherapy, microRNAs, cancer stem cell methods, and targeted interventions within the glycolysis pathway. Through the examination of the complex landscape of meningioma biology and the highlighting of promising therapeutic pathways, this review opens the way for future research efforts aimed at improving patient outcomes in this prevalent intracranial tumor entity.

Cell metabolism: Functional and phenotypic single cell approaches

Several metabolic pathways are essential for the physiological regulation of immune cells, but their dysregulation can cause immune dysfunction. Hypermetabolic and hypometabolic states represent deviations in the magnitude and flexibility of effector cells in different contexts, for example in autoimmunity, infections or cancer. To study immunometabolism, most methods focus on bulk populations and rely on in vitro activation assays. Nowadays, thanks to the development of single-cell technologies, including multiparameter flow cytometry, mass cytometry, RNA cytometry, among others, the metabolic state of individual immune cells can be measured in a variety of samples obtained in basic, translational and clinical studies. Here, we provide an overview of different single-cell approaches that are employed to investigate both mitochondrial functions and cell dependence from mitochondria metabolism. Moreover, besides the description of the appropriate experimental settings, we discuss the strengths and weaknesses of different approaches with the aim to suggest how to study cell metabolism in the settings of interest.

All Three AKT Isoforms Can Upregulate Oxygen Metabolism and Lactate Production in Human Hepatocellular Carcinoma Cell Lines

Hepatocellular carcinoma (HCC), the main pathological type of liver cancer, is related to risk factors such as viral hepatitis, alcohol intake, and non-alcoholic fatty liver disease (NAFLD). The constitutive activation of the PI3K/AKT signaling pathway is common in HCC and has essential involvement in tumor progression. The serine/threonine kinase AKT has several downstream substrates, which have been implicated in the regulation of cellular metabolism. However, the contribution of each of the three AKT isoforms, i.e., AKT1, AKT2 and AKT3, to HCC metabolism has not been comprehensively investigated. In this study, we analyzed the functional role of AKT1, AKT2 and AKT3 in HCC metabolism. The overexpression of activated AKT1, AKT2 and AKT3 isoforms in the human HCC cell lines Hep3B and Huh7 resulted in higher oxygen consumption rate (OCR), ATP production, maximal respiration and spare respiratory capacity in comparison to vector-transduced cells. Vice versa, lentiviral vector-mediated knockdowns of each AKT isoform reduced OCR in both cell lines. Reduced OCR rates observed in the three AKT isoform knockdowns were associated with reduced extracellular acidification rates (ECAR) and reduced lactate production in both analyzed cell lines. Mechanistically, the downregulation of OCR by AKT isoform knockdowns correlated with an increased phosphorylation of the pyruvate dehydrogenase on Ser232, which negatively regulates the activity of this crucial gatekeeper of mitochondrial respiration. In summary, our data indicate that each of the three AKT isoforms is able to upregulate OCR, ECAR and lactate production independently of each other in human HCC cells through the regulation of the pyruvate dehydrogenase.

The Perfect Cup? Coffee-Derived Polyphenols and Their Roles in Mitigating Factors Affecting Type 2 Diabetes Pathogenesis

Type 2 diabetes (T2D) is a growing health concern with an estimated 462 million people having been diagnosed worldwide. T2D is characterized by chronically elevated blood glucose and insulin resistance, which culminate in a diminished function of the β-cell mass in its later stages. This can be perpetuated by and result in inflammation, excess reactive oxygen species production, obesity, and the dysregulation of multiple cellular pathways. Many naturally occurring small molecules have been investigated in terms of their roles in modulating glucose homeostasis and β-cell function. Many of these compounds can be found in commonly used sources of food and drink. Interestingly, a correlation has been observed between coffee consumption and T2D incidence. However, the specific compounds responsible for this correlation and their mechanisms are still somewhat undetermined. This paper reviews recent research findings on the effects of several polyphenols that are either found in coffee or are metabolites of compounds found in coffee (enterodiol, enterolactone, matairesinol, secoisolariciresinol, kaempferol, quercetin, and chlorogenic acid) on glucose homeostasis and health complications associated with glucose dysregulation, with a special emphasis on their potential anti-diabetic effects. The factors that affect polyphenol content in coffee are also addressed.

The mTORC2 signaling network: targets and cross-talks

The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.

Everolimus prevents doxorubicin-induced apoptosis in H9c2 cardiomyocytes but not in MCF-7 cancer cells: Cardioprotective roles of autophagy, mitophagy, and AKT

Cardiotoxicity is a severe side effect of the chemotherapeutic agent doxorubicin (DOX). We recently showed that DOX-induced cardiomyocyte apoptosis and death were attenuated through autophagy pre-induction. Herein, we assessed how the autophagy/mitophagy-inducing antitumor drug everolimus (EVL) affected DOX-induced cytotoxicity in the rat cardiomyocyte cell line H9c2 and human breast cancer cell line MCF-7. Apoptosis was assessed using annexin V assay. Autophagy and mitophagy were assessed using fluorescence assays. Cellular protein levels were determined using western blotting. Pretreatment with EVL (1 nM) before DOX exposure inhibited mammalian target of rapamycin (mTOR) activity, induced autophagy and mitophagy, and activated protein kinase B (AKT) in H9c2 cells. In mitochondria, DOX (1 μM) induced structural damage (decreased membrane potential and release of cytochrome c), increased superoxide levels, decreased apoptosis inhibitor Bcl-2, and increased apoptosis inducer Bax, leading to apoptosis and reduced viability in H9c2 cells. EVL pretreatment suppressed DOX-induced changes. EVL anti-apoptotic effects were inhibited by treatment with MK-2206, a selective AKT inhibitor. Furthermore, EVL suppressed DOX-induced cardiotoxicity through autophagy/mitophagy and AKT activation but did not attenuate DOX-induced apoptosis or reduction in viability in MCF-7 cells. Altogether, EVL can protect cardiomyocytes from DOX-induced apoptosis and toxicity without reducing DOX antitumor effects, allowing safer chemotherapy.

PTPRH promotes the progression of non-small cell lung cancer via glycolysis mediated by the PI3K/AKT/mTOR signaling pathway

BACKGROUND

The protein tyrosine phosphatase H receptor (PTPRH) is known to regulate the occurrence and development of pancreatic and colorectal cancer. However, its association with glycolysis in non-small cell lung cancer (NSCLC) is still unclear. In this study, we aimed to investigate the relationship between PTPRH expression and glucose metabolism and the underlying mechanism of action.

METHODS

The expression of PTPRH in NSCLC cells was evaluated by IHC staining, qRT‒PCR and Western blotting. The effect of PTPRH on cell biological behavior was evaluated by colony assays, EdU experiments, Transwell assays, wound healing assays and flow cytometry. Changes in F-18-fluorodeoxyglucose (18F-FDG) uptake and glucose metabolite levels after altering PTPRH expression were detected via a gamma counter and lactic acid tests. The expression of glycolysis-related proteins in NSCLC cells was detected by Western blotting after altering PTPRH expression.

RESULTS

The results showed that PTPRH was highly expressed in clinical patient tissue samples and closely related to tumor diameter and clinical stage. In addition, PTPRH expression was associated with glycometabolism indexes on 18F-FDG positron emission tomography/computed tomography (PET/CT) imaging, the expression level of Ki67 and the expression levels of glycolysis-related proteins. PTPRH altered cell behavior, inhibited apoptosis, and promoted 18F-FDG uptake, lactate production, and the expression of glycolysis-related proteins. In addition, PTPRH modulated the glycometabolism of NSCLC cells via the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, as assessed using LY294002 and 740Y-P (an inhibitor and agonist of PI3K, respectively). The same results were validated in vivo using a xenograft tumor model in nude mice. Protein expression levels of PTPRH, glycolysis-related proteins, p-PI3K/PI3K and p-AKT/AKT were measured by IHC staining using a subcutaneous xenograft model in nude mice.

CONCLUSIONS

In summary, we report that PTPRH promotes glycolysis, proliferation, migration, and invasion via the PI3K/AKT/mTOR signaling pathway in NSCLC and ultimately promotes tumor progression, which can be regulated by LY294002 and 740Y-P. These results suggest that PTPRH is a potential therapeutic target for NSCLC.

Sodium Butyrate Ameliorates Fluorosis-Induced Neurotoxicity by Regulating Hippocampal Glycolysis In Vivo

Fluorosis can induce neurotoxicity. Sodium butyrate (SB), a histone deacetylase inhibitor, has important research potential in correcting glucose metabolism disorders and is widely used in a variety of neurological diseases and metabolic diseases, but it is not yet known whether it plays a role in combating fluoride-induced neurotoxicity. This study aims to evaluate the effect of SB on fluoride neurotoxicity and the possible associated mechanisms. The results of HE staining and Morris water maze showed that, in mice exposed to 100 mg/L fluoride for 3 months, the hippocampal cells arranged in loosely with large cell gaps and diminished in number. One thousand milligram per kilogram per day SB treatment improved fluoride-induced neuronal cell damage and spatial learning memory impairment. Western blot results showed that the abundance of malate dehydrogenase 2 (MDH2) and pyruvate dehydrogenase (PDH) in the hippocampus of fluorosis mice was increased, the abundance of pyruvate kinase M (PKM), lactate dehydrogenase (LDH), hexokinase (HK), phosphatidylinositol 3-kinase (PI3K), phosphorylated Akt (P-AKT), and hypoxia-inducible factor 1α (HIF-1α) was inhibited, and the content of lactate and ATP was decreased. SB treatment reversed the decreased glycolysis in the hippocampus of fluorosis mice. These results suggested that SB could ameliorate fluorosis-induced neurotoxicity, which might be linked with its function in regulating glycolysis as well as inhibition of the PI3K/AKT/HIF-1α pathway. Sodium butyrate ameliorates fluorosis-induced neurotoxicity by regulating hippocampal glycolysis in vivo (created with MedPeer (www.medpeer.cn)).

The dual role of citrate in cancer

Citrate is a key metabolite of the Krebs cycle that can also be exported in the cytosol, where it performs several functions. In normal cells, citrate sustains protein acetylation, lipid synthesis, gluconeogenesis, insulin secretion, bone tissues formation, spermatozoid mobility, and immune response. Dysregulation of citrate metabolism is implicated in several pathologies, including cancer. Here we discuss how cancer cells use citrate to sustain their proliferation, survival, and metastatic progression. Also, we propose two paradoxically opposite strategies to reduce tumour growth by targeting citrate metabolism in preclinical models. In the first strategy, we propose to administer in the tumor microenvironment a high amount of citrate, which can then act as a glycolysis inhibitor and apoptosis inducer, whereas the other strategy targets citrate transporters to starve cancer cells from citrate. These strategies, effective in several preclinical in vitro and in vivo cancer models, could be exploited in clinics, particularly to increase sensibility to current anti-cancer agents.

Retinoic acid and evernyl-based menadione-triazole hybrid cooperate to induce differentiation of neuroblastoma cells

Neuroblastoma arises when immature neural precursor cells do not mature into specialized cells. Although retinoic acid (RA), a pro-differentiation agent, improves the survival of low-grade neuroblastoma, resistance to retinoic acid is found in high-grade neuroblastoma patients. Histone deacetylases (HDAC) inhibitors induce differentiation and arrest the growth of cancer cells; however, HDAC inhibitors are FDA-approved mostly for liquid tumors. Therefore, combining histone deacetylase (HDAC) inhibitors and retinoic acid can be explored as a strategy to trigger the differentiation of neuroblastoma cells and to overcome resistance to retinoic acid. Based on this rationale, in this study, we linked evernyl group and menadione-triazole motifs to synthesize evernyl-based menadione-triazole hybrids and asked if the hybrids cooperate with retinoic acid to trigger the differentiation of neuroblastoma cells. To answer this question, we treated neuroblastoma cells using evernyl-based menadione-triazole hybrids (6a-6i) or RA or both and examined the differentiation of neuroblastoma cells. Among the hybrids, we found that compound 6b inhibits class-I HDAC activity, induces differentiation, and RA co-treatments increase 6b-induced differentiation of neuroblastoma cells. In addition, 6b reduces cell proliferation, induces expression of differentiation-specific microRNAs leading to N-Myc downregulation, and RA co-treatments enhance the 6b-induced effects. We observed that 6b and RA trigger a switch from glycolysis to oxidative phosphorylation, maintain mitochondrial polarization, and increase oxygen consumption rate. We conclude that in evernyl-based menadione-triazole hybrid, 6b cooperates with RA to induce differentiation of neuroblastoma cells. Based on our results, we suggest that combining RA and 6b can be pursued as therapy for neuroblastoma. Schematic representation of RA and 6b in inducing differentiation of neuroblastoma cells.

A Novel Dual PI3K/mTOR Inhibitor, XIN-10, for the Treatment of Cancer

An imbalance in PI3K/AKT/mTOR pathway signaling in humans often leads to cancer. Therefore, the investigation of anti-cancer medications that inhibit PI3K and mTOR has emerged as a significant area of research. The aim of this study was to explore the effect of XIN-10, a dual PI3K/mTOR inhibitor, on the growth as well as antiproliferation of tumor cells and to investigate the anti-tumor mechanism of XIN-10 by further exploration. We screened three cell lines for more in-depth exploration by MTT experiments. From the AO staining, cell cycle and apoptosis, we found that XIN-10 had a more obvious inhibitory effect on the MCF-7 breast cancer cell line and used this as a selection for more in-depth experiments. A series of in vitro and in vivo experiments showed that XIN-10 has superior antiproliferative activity compared with the positive drug GDC-0941. Meanwhile, through the results of protein blotting and PCR experiments, we concluded that XIN-10 can block the activation of the downstream pathway of mTOR by inhibiting the phosphorylation of AKT(S473) as well as having significant inhibitory effects on the gene exons of PI3K and mTOR. These results indicate that XIN-10 is a highly potent inhibitor with low toxicity and has a strong potential to be developed as a novel PI3Kα/mTOR dual inhibitor candidate for the treatment of positive breast cancer.

Phytochemicals targeting glycolysis in colorectal cancer therapy: effects and mechanisms of action

Colorectal cancer (CRC) is the third most common malignant tumor in the world, and it is prone to recurrence and metastasis during treatment. Aerobic glycolysis is one of the main characteristics of tumor cell metabolism in CRC. Tumor cells rely on glycolysis to rapidly consume glucose and to obtain more lactate and intermediate macromolecular products so as to maintain growth and proliferation. The regulation of the CRC glycolysis pathway is closely associated with several signal transduction pathways and transcription factors including phosphatidylinositol 3-kinases/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), hypoxia-inducible factor-1 (HIF-1), myc, and p53. Targeting the glycolytic pathway has become one of the key research aspects in CRC therapy. Many phytochemicals were shown to exert anti-CRC activity by targeting the glycolytic pathway. Here, we review the effects and mechanisms of phytochemicals on CRC glycolytic pathways, providing a new method of drug development.

Thermo-Chemical Resistance to Combination Therapy of Glioma Depends on Cellular Energy Level

Thermal therapy has been widely used in clinical tumor treatment and more recently in combination with chemotherapy, where the key challenge is the treatment resistance. The mechanism at the cellular level underlying the resistance to thermo-chemical combination therapy remains elusive. In this study, we constructed 3D culture models for glioma cells (i.e., 3D glioma spheres) as the model system to recapitulate the native tumor microenvironment and systematically investigated the thermal response of 3D glioma spheres at different hyperthermic temperatures. We found that 3D glioma spheres show high viability under hyperthermia, especially under high hyperthermic temperatures (42 °C). Further study revealed that the main mechanism lies in the high energy level of cells in 3D glioma spheres under hyperthermia, which enables the cells to respond promptly to thermal stimulation and maintain cellular viability by upregulating the chaperon protein Hsp70 and the anti-apoptotic pathway AKT. Besides, we also demonstrated that 3D glioma spheres show strong drug resistance to the thermo-chemical combination therapy. This study provides a new perspective on understanding the thermal response of combination therapy for tumor treatment.

Metabolic reprogramming in cancer: Mechanisms and therapeutics

Cancer cells characterized by uncontrolled growth and proliferation require altered metabolic processes to maintain this characteristic. Metabolic reprogramming is a process mediated by various factors, including oncogenes, tumor suppressor genes, changes in growth factors, and tumor-host cell interactions, which help to meet the needs of cancer cell anabolism and promote tumor development. Metabolic reprogramming in tumor cells is dynamically variable, depending on the tumor type and microenvironment, and reprogramming involves multiple metabolic pathways. These metabolic pathways have complex mechanisms and involve the coordination of various signaling molecules, proteins, and enzymes, which increases the resistance of tumor cells to traditional antitumor therapies. With the development of cancer therapies, metabolic reprogramming has been recognized as a new therapeutic target for metabolic changes in tumor cells. Therefore, understanding how multiple metabolic pathways in cancer cells change can provide a reference for the development of new therapies for tumor treatment. Here, we systemically reviewed the metabolic changes and their alteration factors, together with the current tumor regulation treatments and other possible treatments that are still under investigation. Continuous efforts are needed to further explore the mechanism of cancer metabolism reprogramming and corresponding metabolic treatments.

Melatonin increases susceptibility to atrial fibrillation in obesity via Akt signaling impairment in response to lipid overload

Melatonin has been proven to have antiarrhythmic potential; however, several studies have recently challenged this view. Herein, using a mouse model of obesity-induced atrial fibrillation (AF), we tentatively explored whether exogenous melatonin supplementation could increase AF susceptibility in the context of obesity. We observed that an 8-week drinking administration of melatonin (60 µg/ml in water) induced a greater susceptibility to AF in obese mice, although obesity-induced structural remodeling was alleviated. An investigation of systemic insulin sensitivity showed that melatonin treatment improved insulin sensitivity in obese mice, whereas it inhibited glucose-stimulated insulin secretion. Notably, melatonin treatment inhibited protein kinase B (Akt) signaling in the atria of obese mice and palmitate-treated neonatal rat cardiomyocytes, thereby providing an AF substrate. Melatonin increased lipid stress in obesity, as evidenced by elevated lipid accumulation and lipolysis-related gene expression, thus contributing to the impairment in atrial Akt signaling. Taken together, our results demonstrated that melatonin could increase AF susceptibility in obesity, probably due to increased lipid stress and resultant impairment of atrial Akt signaling. Our findings suggest that special precautions should be taken when administering melatonin to obese subjects.

Establishment and characterization of a multi-drug resistant cell line for canine mammary tumors

Background and purpose

Canine mammary tumors are the most common tumor disease of female dogs, and adjuvant chemotherapy often results in multi-drug resistance. Currently, the mechanisms underlying the development of tumor multi-drug resistance are unclear. The translation of research applications that can be used to effectively overcome tumor resistance is similarly hampered. Therefore, it is urgent to construct multi-drug resistance models of canine mammary tumors that can be used for research, to explore the mechanisms and means of overcoming resistance.

Materials and methods

In this study, the canine triple negative breast cancer cell line CMT-7364 was induced to develop multidrug resistance using doxorubicin by high-dose drug pulse method. The drug resistance and the expression of drug transport pumps of the cells was verified by CCK8 assay, immunoblotting, qPCR and immunofluorescence. Next, we used scratch assay and Transwell invasion assay to compare the migration and invasion abilities of the two cell lines and examined the expression of EMT-related proteins in both using immunoblotting. The differences of transcriptome between parental and drug-resistant cell lines were detected by RNA-seq sequencing. Finally, mouse xenograft models of drug-resistant and parental cell lines were constructed to evaluate the tumorigenic ability.

Results

After more than 50 generations of continuous passages stimulated by high-dose drug pulse method, the morphology of drug-resistant cell line CMT-7364/R tended to be mesenchymal-like and heterogeneous under light microscopy compared with the parental cell line CMT-7364/S, and developed resistance to doxorubicin and other commonly used chemotherapeutic drugs. In CMT-7364/R, BCRP was expressed at higher levels at both transcriptional and protein levels, while P-glycoprotein was not significantly different. Secondly, the migration and invasion ability of CMT-7364/R was significantly enhanced, with decreased expression of E-cadherin and increased expression of vimentin and mucin 1-N terminus. Finally, mouse xenograft models were constructed, while there was no significant difference in the volume of masses formed at 21 days.

Conclusion

In summary, by using the canine mammary tumor cell line CMT-7364/S as the parental cell line, we successfully constructed a multidrug-resistant CMT-7364/R with high-dose drug pulse methods. Compared to its parental cell line, CMT-7364/R has decreased growth rate, overexpression of BCRP and increased migration and invasion ability due to EMT. The results of this study showed that CMT-7364/R might serve as a model for future studies on tumor drug resistance.

Metabolic Reprogramming and Potential Therapeutic Targets in Lymphoma

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

Intracellular glucose starvation inhibits osteogenic differentiation in human periodontal ligament cells

BACKGROUND

Periodontal ligament cells (PDLCs), as mesenchymal cells in the oral cavity, are closely linked to periodontal tissue regeneration. However, the effect of local glucose deficiency on periodontal tissue regeneration, such as immediately post-surgery, remains unknown.

OBJECTIVE

In the present study, we investigated the effect of a low-glucose environment on the proliferation and osteogenic differentiation of PDLCs.

MATERIALS AND METHODS

We used media with five glucose concentrations (100, 75, 50, 25, and 0 mg/dL) and focused on the effects of a low-glucose environment on the proliferation, osteogenic differentiation, and autophagy of PDLCs. Additionally, we focused on changes in lactate production in a low-glucose environment and investigated the involvement of lactate with AZD3965, a monocarboxylate transporter-1 (MCT-1) inhibitor.

RESULTS

The low-glucose environment inhibited PDLCs proliferation, migration, and osteogenic differentiation, and induced the expression of the autophagy-related factors LC3 and p62. Lactate and ATP production were decreased under low-glucose conditions. The addition of AZD3965 (MCT-1 inhibitor) in normal glucose conditions caused a similar trend as in low-glucose conditions on PDLCs.

CONCLUSION

Our results suggest lactate production through glucose metabolism in the osteogenic differentiation of PDLCs. A low-glucose environment decreased lactate production, inhibiting cell proliferation, migration, and osteogenic differentiation and inducing autophagy in PDLCs.

The PIK3CA-E545K-SIRT4 signaling axis reduces radiosensitivity by promoting glutamine metabolism in cervical cancer

The mutation of glutamic acid 545 to lysine (E545K) in PIK3CA, as the most common missense mutation of this gene in various cancer types, is frequently observed in cervical cancer and has been shown to reduce cervical cancer radiosensitivity. However, the underlying mechanisms remain unclear. Here, we implicate the alterations of glutamine metabolism in PIK3CA-E545K-mediated radioresistance of cervical cancer. Specifically, PIK3CA mutation negatively regulated the expression of SIRT4 via the epigenetic regulator EP300 independently of the canonical mTORC1 pathway. PIK3CA-E545K-induced SIRT4 downregulation promoted cell proliferation, migration, and radiation-induced DNA repair and apoptosis, while SIRT4 overexpression reversed the radioresistance phenotype mediated by PIK3CA mutation. Mechanistically, SIRT4 modulated glutamine metabolism and thus cellular apoptosis by negatively regulating a glutamate pyruvate transaminase GPT1. Moreover, the PI3K inhibitor BYL719, but not mTOR inhibitors, exerted remarkable synergistic effects with radiotherapy by inhibiting glutamine metabolism in vitro and in vivo. Collectively, this study reveals the role of PIK3CA-E545K-SIRT4 axis in regulating glutamine metabolism and the radioresistance in cervical cancer, which provides a necessary preliminary basis for clinical research of PI3K inhibitors as radiosensitizing agents.

The Role of Reprogrammed Glucose Metabolism in Cancer

Cancer cells reprogram their metabolism to meet biosynthetic needs and to adapt to various microenvironments. Accelerated glycolysis offers proliferative benefits for malignant cells by generating glycolytic products that move into branched pathways to synthesize proteins, fatty acids, nucleotides, and lipids. Notably, reprogrammed glucose metabolism and its associated events support the hallmark features of cancer such as sustained cell proliferation, hijacked apoptosis, invasion, metastasis, and angiogenesis. Overproduced enzymes involved in the committed steps of glycolysis (hexokinase, phosphofructokinase-1, and pyruvate kinase) are promising pharmacological targets for cancer therapeutics. In this review, we summarize the role of reprogrammed glucose metabolism in cancer cells and how it can be manipulated for anti-cancer strategies.

Genomic, transcriptomic, and metabolomic analysis of Oldenlandia corymbosa reveals the biosynthesis and mode of action of anti-cancer metabolites

Plants accumulate a vast array of secondary metabolites, which constitute a natural resource for pharmaceuticals. Oldenlandia corymbosa belongs to the Rubiaceae family, and has been used in traditional medicine to treat different diseases, including cancer. However, the active metabolites of the plant, their biosynthetic pathway and mode of action in cancer are unknown. To fill these gaps, we exposed this plant to eight different stress conditions and combined different omics data capturing gene expression, metabolic profiles, and anti-cancer activity. Our results show that O. corymbosa extracts are active against breast cancer cell lines and that ursolic acid is responsible for this activity. Moreover, we assembled a high-quality genome and uncovered two genes involved in the biosynthesis of ursolic acid. Finally, we also revealed that ursolic acid causes mitotic catastrophe in cancer cells and identified three high-confidence protein binding targets by Cellular Thermal Shift Assay (CETSA) and reverse docking. Altogether, these results constitute a valuable resource to further characterize the biosynthesis of active metabolites in the Oldenlandia group, while the mode of action of ursolic acid will allow us to further develop this valuable compound.

The Ketogenic Diet in Colorectal Cancer: A Means to an End

Some diets, such as high lipid and high glucose diets, are known to increase the risk of colorectal cancer. On the other hand, little is known about diets that prevent colonic carcinogenesis. The ketogenic diet, which is characterized by high fat and very low carbohydrate content, is one such diet. The ketogenic diet decreases the amount of available glucose for tumors and shifts to the production of ketone bodies as an alternative energy source for healthy cells. Cancer cells are unable to use the ketone bodies for energy thus depriving them of the energy needed for progression and survival. Many studies reported the beneficial effects of the ketogenic diet in several types of cancers. Recently, the ketone body β-hydroxybutyrate has been found to possess anti-tumor potential in colorectal cancer. Despite its beneficial effects, the ketogenic diet also has some drawbacks, some of which are related to gastrointestinal disorders and weight loss. Thus, studies are being directed at this time towards finding alternatives to following a strict ketogenic diet and supplementing patients with the ketone bodies responsible for its beneficial effects in the hope of overcoming some potential setbacks. This article discusses the mechanism by which a ketogenic diet influences growth and proliferation of tumor cells, it sheds the light on the most recent trials regarding its use as an adjunctive measure to chemotherapy in patients with metastatic colorectal cancer, and it explains the limitations of its usage in metastatic patients and the promising role of exogenous ketone supplementation in this setting.

Cannabinoids Transmogrify Cancer Metabolic Phenotype via Epigenetic Reprogramming and a Novel CBD Biased G Protein-Coupled Receptor Signaling Platform

The concept of epigenetic reprogramming predicts long-term functional health effects. This reprogramming can be activated by exogenous or endogenous insults, leading to altered healthy and different disease states. The exogenous or endogenous changes that involve developing a roadmap of epigenetic networking, such as drug components on epigenetic imprinting and restoring epigenome patterns laid down during embryonic development, are paramount to establishing youthful cell type and health. This epigenetic landscape is considered one of the hallmarks of cancer. The initiation and progression of cancer are considered to involve epigenetic abnormalities and genetic alterations. Cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer development, including DNA methylation, histone modifications, nucleosome positioning, non-coding RNAs, and microRNA expression. Endocannabinoids are natural lipid molecules whose levels are regulated by specific biosynthetic and degradative enzymes. They bind to and activate two primary cannabinoid receptors, type 1 (CB1) and type 2 (CB2), and together with their metabolizing enzymes, form the endocannabinoid system. This review focuses on the role of cannabinoid receptors CB1 and CB2 signaling in activating numerous receptor tyrosine kinases and Toll-like receptors in the induction of epigenetic landscape alterations in cancer cells, which might transmogrify cancer metabolism and epigenetic reprogramming to a metastatic phenotype. Strategies applied from conception could represent an innovative epigenetic target for preventing and treating human cancer. Here, we describe novel cannabinoid-biased G protein-coupled receptor signaling platforms (GPCR), highlighting putative future perspectives in this field.

The Role of Ketogenic Diet in the Treatment of Neuroblastoma

The ketogenic diet (KD) was initially used in 1920 for drug-resistant epileptic patients. From this point onward, ketogenic diets became a pivotal part of nutritional therapy research. To date, KD has shown therapeutic potential in many pathologies such as Alzheimer's disease, Parkinson's disease, autism, brain cancers, and multiple sclerosis. Although KD is now an adjuvant therapy for certain diseases, its effectiveness as an antitumor nutritional therapy is still an ongoing debate, especially in Neuroblastoma. Neuroblastoma is the most common extra-cranial solid tumor in children and is metastatic at initial presentation in more than half of the cases. Although Neuroblastoma can be managed by surgery, chemotherapy, immunotherapy, and radiotherapy, its 5-year survival rate in children remains below 40%. Earlier studies have proposed the ketogenic diet as a possible adjuvant therapy for patients undergoing treatment for Neuroblastoma. In this study, we seek to review the possible roles of KD in the treatment of Neuroblastoma.

Sirtuin 1 aggravates hypertrophic heart failure caused by pressure overload via shifting energy metabolism

Sirtuin1 (SIRT1) is involved in regulating substrate metabolism in the cardiovascular system. Metabolic homeostasis plays a critical role in hypertrophic heart failure. We hypothesize that cardiac SIRT1 can modulate substrate metabolism during pressure overload-induced heart failure. The inducible cardiomyocyte Sirt1 knockout (icSirt1-/-) and its wild type littermates (Sirt1f/f) C57BL/6J mice were subjected to transverse aortic constriction (TAC) surgery to induce pressure overload. The pressure overload induces upregulation of cardiac SIRT1 in Sirt1f/f but not icSirt1-/- mice. The cardiac contractile dysfunctions caused by TAC-induced pressure overload occurred in Sirt1f/f but not in icSirt1-/- mice. Intriguingly, Sirt1f/f heart showed a drastic reduction in systolic contractility and electric signals during post-TAC surgery, whereas icSirt1-/- heart demonstrated significant resistance to pathological stress by TAC-induced pressure overload as evidenced by no significant changes in systolic contractile functions and electric properties. The targeted proteomics showed that the pressure overload triggered downregulation of the SIRT1-associated IDH2 (isocitrate dehydrogenase 2) that resulted in increased oxidative stress in mitochondria. Moreover, metabolic alterations were observed in Sirt1f/f but not in icSirt1-/- heart in response to TAC-induced pressure overload. Thus, SIRT1 interferes with metabolic homeostasis through mitochondrial IDH2 during pressure overload. Inhibition of SIRT1 activity benefits cardiac functions under pressure overload-related pathological conditions.

Age-Related Oxidative Redox and Metabolic Changes Precede Intraneuronal Amyloid-β Accumulation and Plaque Deposition in a Transgenic Alzheimer's Disease Mouse Model

BACKGROUND

Many identified mechanisms could be upstream of the prominent amyloid-β (Aβ) plaques in Alzheimer's disease (AD).

OBJECTIVE

To profile the progression of pathology in AD.

METHODS

We monitored metabolic signaling, redox stress, intraneuronal amyloid-β (iAβ) accumulation, and extracellular plaque deposition in the brains of 3xTg-AD mice across the lifespan.

RESULTS

Intracellular accumulation of aggregated Aβ in the CA1 pyramidal cells at 9 months preceded extracellular plaques that first presented in the CA1 at 16 months of age. In biochemical assays, brain glutathione (GSH) declined with age in both 3xTg-AD and non-transgenic controls, but the decline was accelerated in 3xTg-AD brains from 2 to 4 months. The decline in GSH correlated exponentially with the rise in iAβ. Integrated metabolic signaling as the ratio of phospho-Akt (pAkt) to total Akt (tAkt) in the PI3kinase and mTOR pathway declined at 6, 9, and 12 months, before rising at 16 and 20 months. These pAkt/tAkt ratios correlated with both iAβ and GSH levels in a U-shaped relationship. Selective vulnerability of age-related AD-genotype-specific pAkt changes was greatest in the CA1 pyramidal cell layer. To demonstrate redox causation, iAβ accumulation was lowered in cultured middle-age adult 3xTg-AD neurons by treatment of the oxidized redox state in the neurons with exogenous cysteine.

CONCLUSION

The order of pathologic progression in the 3xTg-AD mouse was loss of GSH (oxidative redox shift) followed by a pAkt/tAkt metabolic shift in CA1, iAβ accumulation in CA1, and extracellular Aβ deposition. Upstream targets may prove strategically more effective for therapy before irreversible changes.

PTEN-knockout regulates metabolic rewiring and epigenetic reprogramming in prostate cancer and chemoprevention by triterpenoid ursolic acid

PTEN (phosphatase and tensin homolog deleted on chromosome 10) is one of the most frequently mutated/deleted tumor suppressor genes in many human cancers. Ursolic acid (UA) is a natural triterpenoid possessing antioxidant, anti-inflammatory, and anticancer effects. However, how PTEN impacts metabolic rewiring and how UA modifies PTEN-driven metabolic and epigenetic reprogramming in prostate cancer (PCa) remains unknown. In the current study, we found that UA protects against PTEN knockout (KO)-induced tumorigenesis at different stages of PCa. Epigenomic CpG methyl-seq revealed UA attenuated PTEN KO-induced differentially methylated regions (DMRs) profiles. Transcriptomic RNA-seq showed UA abrogated PTEN KO-induced differentially expressed genes (DEGs) of PCa-related oncogenes' Has3, Cfh, and Msx1 overexpression, indicating UA plays a crucial role in PTEN KO-mediated gene regulation and its potential consequences on cancer interception. Association analysis of DEGs and DMRs identified that the mRNA expression of tumor suppressor gene BDH2, and oncogenes Ephas, Isg15, and Nos2 were correlated with the promoter CpG methylation status in the early-stage comparison groups indicating UA could regulate the oncogenes or tumor suppressor genes by modulating their promoter methylation at an early stage of prostate tumorigenesis. The metabolomic study showed UA attenuated PTEN KO-regulated cancer-associated metabolisms like purine metabolism/metabolites correlating with RNAseq findings, glycolysis/gluconeogenesis metabolism, as well as epigenetic-related metabolites pyruvate and lactate indicating UA plays a critical role in PTEN KO-mediated metabolic and epigenetic reprogramming and its consequences on cancer development. In this context, UA impacts metabolic rewiring causing epigenetic and transcriptomic reprogramming potentially contributing to the overall protection against prostate-specific PTEN KO-mediated PCa.

BRCA1 overexpression attenuates breast cancer cell growth and migration by regulating the pyruvate kinase M2-mediated Warburg effect via the PI3K/AKT signaling pathway

This work explored the mechanism of the effect of breast-cancer susceptibility gene 1 (BRCA1) on the metabolic characteristics of breast cancer cells, including the Warburg effect and its specific signaling. We transfected MCF-7 cells with a BRCA1-encoding LXSN plasmid or PKM2 siRNA and examined cancer cell metabolism using annexin V staining, inhibitory concentration determination, Western blotting, glucose uptake and lactic acid content measurements, and Transwell assays to assess glycolytic activity, cell apoptosis, and migration, and sensitivity to anti-cancer treatment. The BRCA1-expressing MCF-7 cells demonstrated low PKM2 expression and decreased glycolytic activity (downregulated hexokinase 2 (HK2) expression, upregulated isocitrate dehydrogenase 1 (IDH1) expression, and reduced O₂ and glucose consumption and lactate production) via regulation of PI3K/AKT pathway compared with the empty LXSN group. BRCA1 transfection slightly increased apoptotic activity, decreased cell migration, and increased the IC₅₀ index for doxorubicin, paclitaxel, and cisplatin. Inhibiting PKM2 using siRNA attenuated the IC₅₀ index for doxorubicin, paclitaxel, and cisplatin compared with the control. Inhibiting PKM2 activated PI3K/AKT signaling, increased apoptosis, and decreased MCF-7 cell migration. Our data suggest that BRCA1 overexpression reverses the Warburg effect, inhibits cancer cell growth and migration, and enhances the sensitivity to anti-cancer treatment by decreasing PKM2 expression regulated by PI3K/AKT signaling. These novel metabolic findings represent a potential mechanism by which BRCA1 exerts its inhibitory effect on breast cancer.

Effects of Pgam1-mediated glycolysis pathway in Sertoli cells on Spermatogonial stem cells based on transcriptomics and energy metabolomics

Spermatogenesis is a complex process involving a variety of intercellular interactions and precise regulation of gene expression. Spermatogenesis is sustained by a foundational Spermatogonial stem cells (SSCs) and in mammalian testis. Sertoli cells (SCs) are the major component of SSC niche. Sertoli cells provide structural support and supply energy substrate for developing germ cells. Phosphoglycerate mutase 1 (Pgam1) is a key enzyme in the glycolytic metabolism and our previous work showed that Pgam1 is expressed in SCs. In the present study, hypothesized that Pgam1-depedent glycolysis in SCs plays a functional role in regulating SSCs fate decisions. A co-culture system of murine SCs and primary spermatogonia was constructed to investigate the effects of Pgam1 knockdown or overexpression on SSCs proliferation and differentiation. Transcriptome results indicated that overexpression and knockdown of Pgam1 in SCs resulted in up-regulation of 458 genes (117 down-regulated, 341 up-regulated) and down-regulation of 409 genes (110 down-regulated, 299 up-regulated), respectively. Further analysis of these DEGs revealed that GDNF, FGF2 and other genes that serve key roles in SSCs niche maintenance were regulated by Pgam1. The metabolome results showed that a total of 11 and 16 differential metabolites were identified in the Pgam1 gene overexpression and knockdown respectively. Further screening of these metabolites indicated that Sertoli cell derived glutamate, glutamine, threonine, leucine, alanine, lysine, serine, succinate, fumarate, phosphoenolpyruvate, ATP, ADP, and AMP have potential roles in regulating SSCs proliferation and differentiation. In summary, this study established a SCs-SSCs co-culture system and identified a list of genes and small metabolic molecules that affect the proliferation and differentiation of SSCs. This study provides additional insights into the regulatory mechanisms underlying interactions between SCs and SSCs during mammalian spermatogenesis.

Arsenic exposure elevated ROS promotes energy metabolic reprogramming with enhanced AKT-dependent HK2 expression

Exposure to inorganic or organic arsenic compounds continues to pose substantial public health concerns for hundreds of millions of people around the globe. Highly exposed individuals are susceptible to various illnesses, including impairments and cancers of the lung, liver, skin and bladder. Long-term exposure to low-dose arsenic has been identified to induce aerobic glycolysis, which contributes to cells aberrant proliferation. However, the mechanism underlying arsenic-induced aerobic glycolysis is still unclear. Here, mtDNA copy number is enhanced in arsenic-exposed populations and a positive correlation between serum HK2 and urinary total arsenic was observed in the individuals with high urine arsenic (≥ 0.032 mg/L). In a rat model of trivalent arsenic (iAs³⁺) exposure, the levels of HK2, NDUFA9 and NDUFB8 were increased in the rats treated with iAs³⁺ daily by gavage for 12 weeks than those in the control rats. Subsequently, in a low-dose arsenic exposure cell model we found that 0.2 μmol/L iAs³⁺ induced aerobic glycolysis to promote L-02 cells proliferation and inhibit apoptosis, in which HK2 played an important role. Further studies showed accumulated ROS determined the metabolic reprogramming via activating AKT and then increasing HK2 expression. On the one hand, activated AKT induced aerobic glycolysis by increasing HK2 to promote L-02 cells viability and DNA synthesis; on the other hand, phosphorylated AKT induced HK2 mitochondrial outer-membrane location with VDAC1 to inhibit apoptosis. Taken together, our results indicated that ROS induced by low-dose arsenic exposure determined energy metabolic reprogramming and acted a critical regulator for AKT-dependent HK2 expression and aerobic glycolysis.

Metabolic Switch Under Glucose Deprivation Leading to Discovery of NR2F1 as a Stimulus of Osteoblast Differentiation

Poor survival of grafted cells is the major impediment of successful cell-based therapies for bone regeneration. Implanted cells undergo rapid death in an ischemic environment largely because of hypoxia and metabolic stress from glucose deficiency. Understanding the intracellular metabolic processes and finding genes that can improve cell survival in these inhospitable conditions are necessary to enhance the success of cell therapies. Thus, the purpose of this study was to investigate changes of metabolic profile in glucose-deprived human bone marrow stromal/stem cells (hBMSCs) through metabolomics analysis and discover genes that could promote cell survival and osteogenic differentiation in a glucose-deprived microenvironment. Metabolomics analysis was performed to determine metabolic changes in a glucose stress metabolic model. In the absence of glucose, expression levels of all metabolites involved in glycolysis were significantly decreased than those in a glucose-supplemented state. In glucose-deprived osteogenic differentiation, reliance on tricarboxylic acid cycle (TCA)-predicted oxidative phosphorylation instead of glycolysis as the main mechanism for energy production in osteogenic induction. By comparing differentially expressed genes between glucose-deprived and glucose-supplemented hBMSCs, NR2F1 (Nuclear Receptor Subfamily 2 Group F Member 1) gene was discovered to be associated with enhanced survival and osteogenic differentiation in cells under metabolic stress. Small, interfering RNA (siRNA) for NR2F1 reduced cell viability and osteogenic differentiation of hBMSCs under glucose-supplemented conditions whereas NR2F1 overexpression enhanced osteogenic differentiation and cell survival of hBMSCs in glucose-deprived osteogenic conditions via the protein kinase B (AKT)/extracellular signal-regulated kinase (ERK) pathway. NR2F1-transfected hBMSCs significantly enhanced new bone formation in a critical size long-bone defect of rats compared with control vector-transfected hBMSCs. In conclusion, the results of this study provide an understanding of the metabolic profile of implanted cells in an ischemic microenvironment and demonstrate that NR2F1 treatment may overcome this deprivation by enhancing AKT and ERK regulation. These findings can be utilized in regenerative medicine for bone regeneration. © 2022 American Society for Bone and Mineral Research (ASBMR).