Combination therapy with BPTES nanoparticles and metformin targets the metabolic heterogeneity of pancreatic cancer

Glutaminase inhibition as potential cancer therapeutics: current status and future applications

Alterations in normal metabolic processes are defining features of cancer. Glutamine, an abundant amino acid in the human blood, plays a critical role in regulating several biosynthetic and bioenergetic pathways that support tumour growth. Glutaminolysis is a metabolic pathway that converts glutamine into various metabolites involved in the tricarboxylic acid (TCA) cycle and generates antioxidants that are vital for tumour cell survival. As glutaminase catalyses the initial step of this metabolic pathway, it is of great significance in cancer metabolism and tumour progression. Inhibition of glutaminase and targeting of glutaminolysis have emerged as promising strategies for cancer therapy. This review explores the role of glutaminases in cancer metabolism and discusses various glutaminase inhibitors developed as potential therapies for tumour regression.

Biomimetic Single-Atom Nanozyme for Dual Starvation-Enhanced Breast Cancer Immunotherapy

Cold exposure (CE) therapy is an innovative and cost-efficient cancer treatment that activates brown adipose tissue to compete for glucose uptake, leading to metabolic starvation in tumors. Exploring the combined antitumor mechanisms of CE and traditional therapies (such as nanocatalysis) is exciting and promising. In this study, a platelet membrane biomimetic single-atom nanozyme (SAEs) nanodrug (PFB) carrying bis-2-(5-phenylacetamido-1, 2, 4-thiadiazol-2-yl) ethyl sulfide (BPTES) is developed for use in cancer CE therapy. Owing to the platelet membrane modification, PFB can effectively target tumors. Upon entering cancer cells, the dual starvation effect induced by CE treatment and BPTES can significantly diminish intracellular glucose and ATP levels, resulting in a substantial reduction in cellular (glutathione) GSH, which can enhance the cytotoxic efficacy of reactive oxygen species generated by SAEs. This strategy not only boosts ROS production in tumors, but also strengthens immune responses, particularly by increasing memory T-cell abundance and suppressing distant tumor growth and tumor metastasis. Compared with SAEs therapy alone, this combined approach offers superior benefits for tumor immunotherapy. This study achieves a combination of CE and nanomedicines for the first time, providing new ideas for future nanomedicine combination therapy modalities.

Synergistic Effects of Glutamine Deprivation and Metformin in Acute Myeloid Leukemia

OBJECTIVE

The metabolic reprogramming of acute myeloid leukemia (AML) cells is a compensatory adaptation to meet energy requirements for rapid proliferation. This study aimed to examine the synergistic effects of glutamine deprivation and metformin exposure on AML cells.

METHODS

SKM-1 cells (an AML cell line) were subjected to glutamine deprivation and/or treatment with metformin or bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES, a glutaminase inhibitor) or cytarabine. Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay, and cell apoptosis and reactive oxygen species (ROS) by flow cytometry. Western blotting was conducted to examine the levels of apoptotic proteins, including cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP). Moreover, the human long noncoding RNA (lncRNA) microarray was used to analyze gene expression after glutamine deprivation, and results were confirmed with quantitative RT-PCR (qRT-PCR). The expression of metallothionein 2A (MT2A) was suppressed using siRNA. Cell growth and apoptosis were further detected by CCK-8 assay and flow cytometry, respectively, in cells with MT2A knockdown.

RESULTS

Glutamine deprivation or treatment with BPTES inhibited cell growth and induced apoptosis in SKM-1 cells. The lncRNA microarray result showed that the expression of MT family genes was significantly upregulated after glutamine deprivation. MT2A knockdown increased apoptosis, while proliferation was not affected in SKM-1 cells. In addition, metformin inhibited cell growth and induced apoptosis in SKM-1 cells. Both glutamine deprivation and metformin enhanced the sensitivity of SKM-1 cells to cytarabine. Furthermore, the combination of glutamine deprivation with metformin exhibited synergistic antileukemia effects on SKM-1 cells.

CONCLUSION

Targeting glutamine metabolism in combination with metformin is a promising new therapeutic strategy for AML.

Glycosylated nanoplatforms: From glycosylation strategies to implications and opportunities for cancer theranostics

Glycosylated nanoplatforms have emerged as promising tools in the field of cancer theranostics, integrating both therapeutic and diagnostic functionalities. These nanoscale platforms are composed of different materials such as lipids, polymers, carbons, and metals that can be modified with glycosyl moieties to enhance their targeting capabilities towards cancer cells. This review provides an overview of different modification strategies employed to introduce glycosylation onto nanoplatforms, including chemical conjugation, enzymatic methods, and bio-orthogonal reactions. Furthermore, the potential applications of glycosylated nanoplatforms in cancer theranostics are discussed, focusing on their roles in drug delivery, imaging, and combination therapy. The ability of these nanoplatforms to selectively target cancer cells through specific interactions with overexpressed glycan receptors is highlighted, emphasizing their potential for enhancing efficacy and reducing the side effects compared to conventional therapies. In addition, the incorporation of diagnostic components onto the glycosylated nanoplatforms provided the capability of simultaneous imaging and therapy and facilitated the real-time monitoring of treatment response. Finally, challenges and future perspectives in the development and translation of glycosylated nanoplatforms for clinical applications are addressed, including scalability, biocompatibility, and regulatory considerations. Overall, this review underscores the significant progress made in the field of glycosylated nanoplatforms and their potential to revolutionize cancer theranostics.

Decoding mitochondria's role in immunity and cancer therapy

The functions of mitochondria, including energy production and biomolecule synthesis, have been known for a long time. Given the rising incidence of cancer, the role of mitochondria in cancer has become increasingly popular. Activated by components released by mitochondria, various pathways interact with each other to induce immune responses to protect organisms from attack. However, mitochondria play dual roles in the progression of cancer. Abnormalities in proteins, which are the elementary structures of mitochondria, are closely linked with oncogenesis. Both the aberrant accumulation of intermediates and mutations in enzymes result in the generation and progression of cancer. Therefore, targeting mitochondria to treat cancer may be a new strategy. Several drugs aimed at inhibiting mutated enzymes and accumulated intermediates have been tested clinically. Here, we discuss the current understanding of mitochondria in cancer and the interactions between mitochondrial functions, immune responses, and oncogenesis. Furthermore, we discuss mitochondria as hopeful targets for cancer therapy, providing insights into the progression of future therapeutic strategies.

Amino acid metabolic reprogramming in the tumor microenvironment and its implication for cancer therapy

Amino acids are essential building blocks for proteins, crucial energy sources for cell survival, and key signaling molecules supporting the resistant growth of tumor cells. In tumor cells, amino acid metabolic reprogramming is characterized by the enhanced uptake of amino acids as well as their aberrant synthesis, breakdown, and transport, leading to immune evasion and malignant progression of tumor cells. This article reviews the altered amino acid metabolism in tumor cells and its impact on tumor microenvironment, and also provides an overview of the current clinical applications of amino acid metabolism. Innovative drugs targeting amino acid metabolism hold great promise for precision and personalized cancer therapy.

Strategic disruption of cancer's powerhouse: precise nanomedicine targeting of mitochondrial metabolism

Mitochondria occupy a central role in the biology of most eukaryotic cells, functioning as the hub of oxidative metabolism where sugars, fats, and amino acids are ultimately oxidized to release energy. This crucial function fuels a variety of cellular activities. Disruption in mitochondrial metabolism is a common feature in many diseases, including cancer, neurodegenerative conditions and cardiovascular diseases. Targeting tumor cell mitochondrial metabolism with multifunctional nanosystems emerges as a promising strategy for enhancing therapeutic efficacy against cancer. This review comprehensively outlines the pathways of mitochondrial metabolism, emphasizing their critical roles in cellular energy production and metabolic regulation. The associations between aberrant mitochondrial metabolism and the initiation and progression of cancer are highlighted, illustrating how these metabolic disruptions contribute to oncogenesis and tumor sustainability. More importantly, innovative strategies employing nanomedicines to precisely target mitochondrial metabolic pathways in cancer therapy are fully explored. Furthermore, key challenges and future directions in this field are identified and discussed. Collectively, this review provides a comprehensive understanding of the current state and future potential of nanomedicine in targeting mitochondrial metabolism, offering insights for developing more effective cancer therapies.

Biochemical hallmarks-targeting antineoplastic nanotherapeutics

Tumor microenvironments (TMEs) have received increasing attention in recent years as they play pivotal roles in tumorigenesis, progression, metastases, and resistance to the traditional modalities of cancer therapy like chemotherapy. With the rapid development of nanotechnology, effective antineoplastic nanotherapeutics targeting the aberrant hallmarks of TMEs have been proposed. The appropriate design and fabrication endow nanomedicines with the abilities for active targeting, TMEs-responsiveness, and optimization of physicochemical properties of tumors, thereby overcoming transport barriers and significantly improving antineoplastic therapeutic benefits. This review begins with the origins and characteristics of TMEs and discusses the latest strategies for modulating the TMEs by focusing on the regulation of biochemical microenvironments, such as tumor acidosis, hypoxia, and dysregulated metabolism. Finally, this review summarizes the challenges in the development of smart anti-cancer nanotherapeutics for TME modulation and examines the promising strategies for combination therapies with traditional treatments for further clinical translation.

Comprehensive proteogenomic characterization of rare kidney tumors

Non-clear cell renal cell carcinomas (non-ccRCCs) encompass diverse malignant and benign tumors. Refinement of differential diagnosis biomarkers, markers for early prognosis of aggressive disease, and therapeutic targets to complement immunotherapy are current clinical needs. Multi-omics analyses of 48 non-ccRCCs compared with 103 ccRCCs reveal proteogenomic, phosphorylation, glycosylation, and metabolic aberrations in RCC subtypes. RCCs with high genome instability display overexpression of IGF2BP3 and PYCR1. Integration of single-cell and bulk transcriptome data predicts diverse cell-of-origin and clarifies RCC subtype-specific proteogenomic signatures. Expression of biomarkers MAPRE3, ADGRF5, and GPNMB differentiates renal oncocytoma from chromophobe RCC, and PIGR and SOSTDC1 distinguish papillary RCC from MTSCC. This study expands our knowledge of proteogenomic signatures, biomarkers, and potential therapeutic targets in non-ccRCC.

Metabolic reprogramming and interventions in angiogenesis

BACKGROUND

Endothelial cell (EC) metabolism plays a crucial role in the process of angiogenesis. Intrinsic metabolic events such as glycolysis, fatty acid oxidation, and glutamine metabolism, support secure vascular migration and proliferation, energy and biomass production, as well as redox homeostasis maintenance during vessel formation. Nevertheless, perturbation of EC metabolism instigates vascular dysregulation-associated diseases, especially cancer.

AIM OF REVIEW

In this review, we aim to discuss the metabolic regulation of angiogenesis by EC metabolites and metabolic enzymes, as well as prospect the possible therapeutic opportunities and strategies targeting EC metabolism.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this work, we discuss various aspects of EC metabolism considering normal and diseased vasculature. Of relevance, we highlight that the implications of EC metabolism-targeted intervention (chiefly by metabolic enzymes or metabolites) could be harnessed in orchestrating a spectrum of pathological angiogenesis-associated diseases.

Cancer cells employ lipid droplets to survive toxic stress

BACKGROUND

Lipid reprogramming is a known mechanism to increase the energetic demands of proliferating cancer cells to drive and support tumorigenesis and progression. Elevated lipid droplets (LDs) are a well-known alteration of lipid reprogramming in many cancers, including prostate cancer (PCa), and are associated with high tumor aggressiveness as well as therapy resistance. The mechanism of LD accumulation and specific LD functions are still not well understood; however, it has been shown that LDs can form as a protective mechanism against lipotoxicity and lipid peroxidation in the cell.

METHODS

This study investigated the significance of LDs in PCa. This was done by staining, imaging, image quantification, and flow cytometry analysis of LDs in PCa cells. Additionally, lipidomics and metabolomics experiments were performed to assess the difference of metabolites and lipids in control and treatment surviving cancer cells. Lastly, to assess clinical significance, multiple publicly available datasets were mined for LD-related data.

RESULTS

Our study demonstrated that prostate and breast cancer cells that survive 72 h of chemotherapy treatment have elevated LDs. These LDs formed in tandem with elevated reactive oxygen species levels to sequester damaged and excess lipids created by oxidative stress, which promoted cell survival. Additionally, by inhibiting diacylglycerol O-acyltransferase 1 (DGAT1) (which catalyzes triglyceride synthesis into LDs) and treating with chemotherapy simultaneously, we were able to decrease the overall amount of LDs and increase cancer cell death compared to treating with chemotherapy alone.

CONCLUSIONS

Overall, our study proposes a potential combination therapy of DGAT1 inhibitors and chemotherapy to increase cancer cell death.

Nanomedomics

Nanomaterials have attractive physicochemical properties. A variety of nanomaterials such as inorganic, lipid, polymers, and protein nanoparticles have been widely developed for nanomedicine via chemical conjugation or physical encapsulation of bioactive molecules. Superior to traditional drugs, nanomedicines offer high biocompatibility, good water solubility, long blood circulation times, and tumor-targeting properties. Capitalizing on this, several nanoformulations have already been clinically approved and many others are currently being studied in clinical trials. Despite their undoubtful success, the molecular mechanism of action of the vast majority of nanomedicines remains poorly understood. To tackle this limitation, herein, this review critically discusses the strategy of applying multiomics analysis to study the mechanism of action of nanomedicines, named nanomedomics, including advantages, applications, and future directions. A comprehensive understanding of the molecular mechanism could provide valuable insight and therefore foster the development and clinical translation of nanomedicines.

Exploiting the Achilles' heel of cancer: disrupting glutamine metabolism for effective cancer treatment

Cancer cells have adapted to rapid tumor growth and evade immune attack by reprogramming their metabolic pathways. Glutamine is an important nitrogen resource for synthesizing amino acids and nucleotides and an important carbon source in the tricarboxylic acid (TCA) cycle and lipid biosynthesis pathway. In this review, we summarize the significant role of glutamine metabolism in tumor development and highlight the vulnerabilities of targeting glutamine metabolism for effective therapy. In particular, we review the reported drugs targeting glutaminase and glutamine uptake for efficient cancer treatment. Moreover, we discuss the current clinical test about targeting glutamine metabolism and the prospective direction of drug development.

Removal of gemcitabine-induced senescent cancer cells by targeting glutaminase1 improves the therapeutic effect in pancreatic ductal adenocarcinoma

Insufficient cancer treatment can induce senescent cancer cell formation and treatment resistance. The characteristics of induced senescent cancer (iSnCa) cells remain unclear. Pancreatic ductal adenocarcinoma (PDAC) has a low and nondurable response rate to current treatments. Our study aimed to analyze the properties of iSnCa cells and the relationship between cellular senescence and prognosis in PDAC. We evaluated the characteristics of gemcitabine-induced senescent cancer cells and the effect of senescence-associated secretory phenotype (SASP) factors released by iSnCa cells on surrounding PDAC cells. The relationship between cellular senescence and the prognosis was investigated in 50 patients with PDAC treated with gemcitabine-based neoadjuvant chemotherapy. Exposure to 5 ng/mL gemcitabine-induced senescence, decreased proliferation and increased senescence-associated β-galactosidase-cell staining without cell death in PDAC cells; the expression of glutaminase1 (GLS1) and SASP factors also increased and caused epithelial-mesenchymal transition in surrounding PDAC cells. iSnCa cells were selectively removed by the GLS1 inhibitor bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) through apoptosis induction. Cellular senescence was induced in PDAC cells via insufficient gemcitabine in subcutaneous tumor model mice. GLS1 expression was an independent prognostic factor in patients with PDAC who received gemcitabine-based neoadjuvant chemotherapy. This is the first study to identify the relationship between senescence and GLS1 in PDAC. Low-dose gemcitabine-induced senescence and increased GLS1 expression were observed in PDAC cells. Cellular senescence may contribute to treatment resistance of PDAC, hence targeting GLS1 in iSnCa cells may improve the therapeutic effect.

Dietary approaches for exploiting metabolic vulnerabilities in cancer

Renewed interest in tumor metabolism sparked an enthusiasm for dietary interventions to prevent and treat cancer. Changes in diet impact circulating nutrient levels in the plasma and the tumor microenvironment, and preclinical studies suggest that dietary approaches, including caloric and nutrient restrictions, can modulate tumor initiation, progression, and metastasis. Cancers are heterogeneous in their metabolic dependencies and preferred energy sources and can be addicted to glucose, fructose, amino acids, or lipids for survival and growth. This dependence is influenced by tumor type, anatomical location, tissue of origin, aberrant signaling, and the microenvironment. This review summarizes nutrient dependencies and the related signaling pathway activations that provide targets for nutritional interventions. We examine popular dietary approaches used as adjuvants to anticancer therapies, encompassing caloric restrictions, including time-restricted feeding, intermittent fasting, fasting-mimicking diets (FMDs), and nutrient restrictions, notably the ketogenic diet. Despite promising results, much of the knowledge on dietary restrictions comes from in vitro and animal studies, which may not accurately reflect real-life situations. Further research is needed to determine the optimal duration, timing, safety, and efficacy of dietary restrictions for different cancers and treatments. In addition, well-designed human trials are necessary to establish the link between specific metabolic vulnerabilities and targeted dietary interventions. However, low patient compliance in clinical trials remains a significant challenge.

A PD-L1-targeting Regulator for Metabolic Reprogramming to Enhance Glutamine Inhibition-Mediated Synergistic Antitumor Metabolic and Immune Therapy

Inhibition of glutamine metabolism in tumor cells can cause metabolic compensation-mediated glycolysis enhancement and PD-L1 upregulation-induced immune evasion, significantly limiting the therapeutic efficacy of glutamine inhibitors. Here, inspired by the specific binding of receptor and ligand, a PD-L1-targeting metabolism and immune regulator (PMIR) are constructed by decorating the glutaminase inhibitor (BPTES)-loading zeolitic imidazolate framework (ZIF) with PD-L1-targeting peptides for regulating the metabolism within the tumor microenvironment (TME) to improve immunotherapy. At tumor sites, PMIR inhibits glutamine metabolism of tumor cells for elevating glutamine levels within the TME to improve the function of immune cells. Ingeniously, the accompanying PD-L1 upregulation on tumor cells causes self-amplifying accumulation of PMIR through PD-L1 targeting, while also blocking PD-L1, which has the effects of converting enemies into friends. Meanwhile, PMIR exactly offsets the compensatory glycolysis, while disrupting the redox homeostasis in tumor cells via the cooperation of components of the ZIF and BPTES. These together cause immunogenic cell death of tumor cells and relieve PD-L1-mediated immune evasion, further reshaping the immunosuppressive TME and evoking robust immune responses to effectively suppress bilateral tumor progression and metastasis. This work proposes a rational strategy to surmount the obstacles in glutamine inhibition for boosting existing clinical treatments.

Enhancement of targeted therapy in combination with metformin on human breast cancer cell lines

BACKGROUND

Breast cancer remains a primary global health concern due to its limited treatment options, frequent disease recurrence, and high rates of morbidity and mortality. Thereby, there is a need for more effective treatment approaches. The proposal suggests that the combination of targeted therapy with other antitumoral agents could potentially address drug resistance. In this study, we examined the antitumoral effect of combining metformin, an antidiabetic drug, with targeted therapies, including tamoxifen for estrogen receptor-positive (MCF-7), trastuzumab for HER2-positive (SKBR-3), and antibody against ROR1 receptor for triple-negative breast cancer (MDA-MB-231).

METHODS

Once the expression of relevant receptors on each cell line was confirmed and appropriate drug concentrations were selected through cytotoxicity assays, the antitumor effects of both monotherapy and combination therapy on colony formation, migration, invasion were assessed in in vitro as well as tumor area and metastatic potential in ex ovo Chick chorioallantoic membrane (CAM) models.

RESULTS

The results exhibited the enhanced effects of tamoxifen when combined with targeted therapy. This combination effectively inhibited cell growth, colony formation, migration, and invasion in vitro. Additionally, it significantly reduced tumor size and metastatic potential in an ex ovo CAM model.

CONCLUSIONS

The findings indicate that a favorable strategy to enhance the efficacy of breast cancer treatment would be to combine metformin with targeted therapies.

Recent progress in the development of nanomaterials targeting multiple cancer metabolic pathways: a review of mechanistic approaches for cancer treatment

Cancer is a very heterogeneous disease, and uncontrolled cell division is the main characteristic of cancer. Cancerous cells need a high nutrition intake to enable aberrant growth and survival. To do so, cancer cells modify metabolic pathways to produce energy and anabolic precursors and preserve redox balance. Due to the importance of metabolic pathways in tumor growth and malignant transformation, metabolic pathways have also been given promising perspectives for cancer treatment, providing more effective treatment strategies, and target-specific with minimum side effects. Metabolism-based therapeutic nanomaterials for targeted cancer treatment are a promising option. Numerous types of nanoparticles (NPs) are employed in the research and analysis of various cancer therapies. The current review focuses on cutting-edge strategies and current cancer therapy methods based on nanomaterials that target various cancer metabolisms. Additionally, it highlighted the primacy of NPs-based cancer therapies over traditional ones, the challenges, and the future potential.

Glutamine addiction and therapeutic strategies in pancreatic cancer

Pancreatic cancer remains one of the most lethal diseases worldwide owing to its late diagnosis, early metastasis, and poor prognosis. Because current therapeutic options are limited, there is an urgent need to investigate novel targeted treatment strategies. Pancreatic cancer faces significant metabolic challenges, principally hypoxia and nutrient deprivation, due to specific microenvironmental constraints, including an extensive desmoplastic stromal reaction. Pancreatic cancer cells have been shown to rewire their metabolism and energy production networks to support rapid survival and proliferation. Increased glucose uptake and glycolytic pathway activity during this process have been extensively described. However, growing evidence suggests that pancreatic cancer cells are glutamine addicted. As a nitrogen source, glutamine directly (or indirectly via glutamate conversion) contributes to many anabolic processes in pancreatic cancer, including amino acids, nucleobases, and hexosamine biosynthesis. It also plays an important role in redox homeostasis, and when converted to α-ketoglutarate, glutamine serves as an energy and anaplerotic carbon source, replenishing the tricarboxylic acid cycle intermediates. The present study aims to provide a comprehensive overview of glutamine metabolic reprogramming in pancreatic cancer, focusing on potential therapeutic approaches targeting glutamine metabolism in pancreatic cancer.

Glycolysis in human cancers: Emphasis circRNA/glycolysis axis and nanoparticles in glycolysis regulation in cancer therapy

The metabolism of cancer has been an interesting hallmark and metabolic reprogramming, especially the change from oxidative phosphorylation in mitochondria to glucose metabolism known as glycolysis occurs in cancer. The molecular profile of glycolysis, related molecular pathways and enzymes involved in this mechanism such as hexokinase have been fully understood. The glycolysis inhibition can significantly decrease tumorigenesis. On the other hand, circRNAs are new emerging non-coding RNA (ncRNA) molecules with potential biological functions and aberrant expression in cancer cells which have received high attention in recent years. CircRNAs have a unique covalently closed loop structure which makes them highly stable and reliable biomarkers in cancer. CircRNAs are regulators of molecular mechanisms including glycolysis. The enzymes involved in the glycolysis mechanism such as hexokinase are regulated by circRNAs to modulate tumor progression. Induction of glycolysis by circRNAs can significantly increase proliferation rate of cancer cells given access to energy and enhance metastasis. CircRNAs regulating glycolysis can influence drug resistance in cancers because of theirimpact on malignancy of tumor cells upon glycolysis induction. TRIM44, CDCA3, SKA2 and ROCK1 are among the downstream targets of circRNAs in regulating glycolysis in cancer. Additionally, microRNAs are key regulators of glycolysis mechanism in cancer cells and can affect related molecular pathways and enzymes. CircRNAs sponge miRNAs to regulate glycolysis as a main upstream mediator. Moreover, nanoparticles have been emerged as new tools in tumorigenesis suppression and in addition to drug and gene delivery, then mediate cancer immunotherapy and can be used for vaccine development. The nanoparticles can delivery circRNAs in cancer therapy and they are promising candidates in regulation of glycolysis, its suppression and inhibition of related pathways such as HIF-1α. The stimuli-responsive nanoparticles and ligand-functionalized ones have been developed for selective targeting of glycolysis and cancer cells, and mediating carcinogenesis inhibition.

Participation of protein metabolism in cancer progression and its potential targeting for the management of cancer

Cancer malignancies may broadly be described as heterogeneous disorders manifested by uncontrolled cellular growth/division and proliferation. Tumor cells utilize metabolic reprogramming to accomplish the upregulated nutritional requirements for sustaining their uncontrolled growth, proliferation, and survival. Metabolic reprogramming also called altered or dysregulated metabolism undergoes modification in normal metabolic pathways for anabolic precursor's generation that serves to continue biomass formation that sustains the growth, proliferation, and survival of carcinogenic cells under a nutrition-deprived microenvironment. A wide range of dysregulated/altered metabolic pathways encompassing different metabolic regulators have been described; however, the current review is focused to explain deeply the metabolic pathways modifications inducing upregulation of proteins/amino acids metabolism. The essential modification of various metabolic cycles with their consequent outcomes meanwhile explored promising therapeutic targets playing a pivotal role in metabolic regulation and is successfully employed for effective target-specific cancer treatment. The current review is aimed to understand the metabolic reprogramming of different proteins/amino acids involved in tumor progression along with potential therapeutic perspective elucidating targeted cancer therapy via these targets.

Metabolic Heterogeneity, Plasticity, and Adaptation to "Glutamine Addiction" in Cancer Cells: The Role of Glutaminase and the GTωA [Glutamine Transaminase-ω-Amidase (Glutaminase II)] Pathway

Many cancers utilize l-glutamine as a major energy source. Often cited in the literature as "l-glutamine addiction", this well-characterized pathway involves hydrolysis of l-glutamine by a glutaminase to l-glutamate, followed by oxidative deamination, or transamination, to α-ketoglutarate, which enters the tricarboxylic acid cycle. However, mammalian tissues/cancers possess a rarely mentioned, alternative pathway (the glutaminase II pathway): l-glutamine is transaminated to α-ketoglutaramate (KGM), followed by ω-amidase (ωA)-catalyzed hydrolysis of KGM to α-ketoglutarate. The name glutaminase II may be confused with the glutaminase 2 (GLS2) isozyme. Thus, we recently renamed the glutaminase II pathway the "glutamine transaminase-ω-amidase (GTωA)" pathway. Herein, we summarize the metabolic importance of the GTωA pathway, including its role in closing the methionine salvage pathway, and as a source of anaplerotic α-ketoglutarate. An advantage of the GTωA pathway is that there is no net change in redox status, permitting α-ketoglutarate production during hypoxia, diminishing cellular energy demands. We suggest that the ability to coordinate control of both pathways bestows a metabolic advantage to cancer cells. Finally, we discuss possible benefits of GTωA pathway inhibitors, not only as aids to studying the normal biological roles of the pathway but also as possible useful anticancer agents.

pH-sensitive tumor-tropism hybrid membrane-coated nanoparticles for reprogramming the tumor microenvironment and boosting the antitumor immunity

Metabolic dysregulation contributes not only to cancer development but also to a tumor immune microenvironment (TIME), which poses great challenges to chemo- and immunotherapy. Targeting metabolic reprogramming has recently emerged as a promising strategy for cancer treatment, but the lethality against solid tumors appears to be fairly restricted, partially due to the poor solubility of small molecule drugs. Herein, we construct a versatile biomimetic nanoplatform (referred to as HM-BPT) employing pH-sensitive tumor-tropism hybrid membrane-coated Manganese oxide (MnO2) nanoparticles for the delivery of BPTES, a glutamine metabolism inhibitor. Basically, hybrid membranes consisting of mesenchymal stem cell membranes (MSCm) and pH-sensitive liposomes (pSL) enable the biomimetic nanoplatform to target TME and escape from endo/lysosomes after endocytosis. The results reveal that HM-BPT treatment leads to remarkable tumor inhibition, cytotoxic T lymphocyte (CTL) infiltration, as well as M1 phenotype repolarization and stimulator of IFN genes (STING) pathway activation in macrophages in a 4T1 xenograft model. Furthermore, glutathione (GSH) depletion and oxygen (O2) supply synergistically ameliorate the immunosuppressive status of the TME, boosting potent antitumor immune responses. Overall, our study explores an integrated therapeutic platform for TME reprogramming and immune activation, offering tremendous promise for cancer combination therapy. STATEMENT OF SIGNIFICANCE: Metabolic abnormalities and the tumor immune microenvironment (TIME) lead to hyporesponsiveness to conventional therapies, ultimately resulting in refractory malignancies. In the current work, a biomimetic nanoplatform (HM-BPT) was developed for TME metabolic reprogramming in favor of immunotherapy. Particularly, hybrid membrane camouflage endowed the nanoplatform with TME targeting, endo/lysosomal escape, and sensitive release properties. The impact of hybrid membrane fusion ratio on cellular uptake and cell viability was explored, yielding beneficial references for the future development of bioactive nanomaterials. Intravenous administration of HM-BPT substantially relieved tumor burden and restored innate and acquired immune activation in 4T1 xenograft models. In conclusion, the created HM-BPT system has the potential to be a promising nanoplatform for combining cancer therapies.

Metabolomics in drug research and development: The recent advances in technologies and applications

Emerging evidence has demonstrated the vital role of metabolism in various diseases or disorders. Metabolomics provides a comprehensive understanding of metabolism in biological systems. With advanced analytical techniques, metabolomics exhibits unprecedented significant value in basic drug research, including understanding disease mechanisms, identifying drug targets, and elucidating the mode of action of drugs. More importantly, metabolomics greatly accelerates the drug development process by predicting pharmacokinetics, pharmacodynamics, and drug response. In addition, metabolomics facilitates the exploration of drug repurposing and drug-drug interactions, as well as the development of personalized treatment strategies. Here, we briefly review the recent advances in technologies in metabolomics and update our knowledge of the applications of metabolomics in drug research and development.

c-Myc protects hepatocellular carcinoma cell from ferroptosis induced by glutamine deprivation via upregulating GOT1 and Nrf2

BACKGROUND

Glutamine metabolism is critical for development of hepatocellular carcinoma (HCC), which makes it a novel promising treatment target. However, clinical evidence suggested glutamine withdrawal therapy does not achieved the desired tumor suppression. Therefore, it is valuable to investigate the survival mechanisms of tumors with glutamine deprivation.

METHODS

The HCC cells were cultured in glutamine-free medium or supplemented with glutamine metabolites or ferroptosis inhibitors. The parameters related to ferroptosis and the activity of GSH synthesis-related enzymes of the HCC cells were detected by corresponding kits. The expressions of glutamate oxaloacetate transaminase 1 (GOT1), c-Myc and Nrf2 were detected by western blot and qRT-PCR. The chromatin immunoprecipitation and luciferase reporter assays were performed to investigate the correlation between c-Myc and GOT1. The siRNAs of c-Myc and GOT1 were used to explore their roles in GSH (GSH) synthesis and ferroptosis in vitro and in vivo.

RESULTS

Glutamine deprivation-induced ferroptosis did not completely inhibit HCC cells proliferation. Glutamine deprivation activated the expression of c-Myc, which promoted the transcription of GOT1 and Nrf2, consequently maintaining the GSH synthesis and inhibiting ferroptosis. In addition, combined inhibition of GOT1 with glutamine deprivation could result in better inhibition of HCC in vitro and in vivo.

CONCLUSIONS

In our work, the results indicate that GOT1 induced by c-Myc may play an important role in combating ferroptosis due to glutamine deprivation, making it a significant target in glutamine withdrawal therapy. This study provides a theoretical foundation for the clinical targeted therapy for HCC.

Unveiling the veil of lactate in tumor-associated macrophages: a successful strategy for immunometabolic therapy

Lactate, traditionally regarded as a metabolic waste product at the terminal of the glycolysis process, has recently been found to have multifaceted functional roles in metabolism and beyond. A metabolic reprogramming phenomenon commonly seen in tumor cells, known as the "Warburg effect," sees high levels of aerobic glycolysis result in an excessive production of lactate. This lactate serves as a substrate that sustains not only the survival of cancer cells but also immune cells. However, it also inhibits the function of tumor-associated macrophages (TAMs), a group of innate immune cells ubiquitously present in solid tumors, thereby facilitating the immune evasion of malignant tumor cells. Characterized by their high plasticity, TAMs are generally divided into the pro-inflammatory M1 phenotype and the pro-tumour M2 phenotype. Through a process of 'education' by lactate, TAMs tend to adopt an immunosuppressive phenotype and collaborate with tumor cells to promote angiogenesis. Additionally, there is growing evidence linking metabolic reprogramming with epigenetic modifications, suggesting the participation of histone modification in diverse cellular events within the tumor microenvironment (TME). In this review, we delve into recent discoveries concerning lactate metabolism in tumors, with a particular focus on the impact of lactate on the function of TAMs. We aim to consolidate the molecular mechanisms underlying lactate-induced TAM polarization and angiogenesis and explore the lactate-mediated crosstalk between TAMs and tumor cells. Finally, we also touch upon the latest progress in immunometabolic therapies and drug delivery strategies targeting glycolysis and lactate production, offering new perspectives for future therapeutic approaches.

Activation of Piezo1 promotes osteogenic differentiation of aortic valve interstitial cell through YAP-dependent glutaminolysis

Hemodynamic overload and dysregulation of cellular metabolism are involved in development of calcific aortic valve disease (CAVD). However, how mechanical stress relates to metabolic changes in CAVD remains unclear. Here, we show that Piezo1, a mechanosensitive ion channel, regulated glutaminase 1 (GLS1)-mediated glutaminolysis to promote osteogenic differentiation of valve interstitial cells (VICs). In vivo, two models of aortic valve stenosis were constructed by ascending aortic constriction (AAC) and direct wire injury (DWI). Inhibition of Piezo1 and GLS1 in these models respectively mitigated aortic valve lesion. In vitro, Piezo1 activation induced by Yoda1 and oscillatory stress triggered osteogenic responses in VICs, which were prevented by Piezo1 inhibition or knockdown. Mechanistically, Piezo1 activation promoted calcium-dependent Yes-associated protein (YAP) activation. YAP modulated GLS1-mediated glutaminolysis, which enhanced osteogenic differentiation through histone acetylation of runt-related transcription factor 2 (RUNX2) promoters. Together, our work provided a cross-talk between mechanotransduction and metabolism in the context of CAVD.

Genetic Ablation of LAT1 Inhibits Growth of Liver Cancer Cells and Downregulates mTORC1 Signaling

Through a comprehensive analysis of the gene expression and dependency in HCC patients and cell lines, LAT1 was identified as the top amino acid transporter candidate supporting HCC tumorigenesis. To assess the suitability of LAT1 as a HCC therapeutic target, we used CRISPR/Cas9 to knockout (KO) LAT1 in the epithelial HCC cell line, Huh7. Knockout of LAT1 diminished its branched chain amino acid (BCAA) transport activity and significantly reduced cell proliferation in Huh7. Consistent with in vitro studies, LAT1 ablation led to suppression of tumor growth in a xenograft model. To elucidate the mechanism underlying the observed inhibition of cell proliferation upon LAT1 KO, we performed RNA-sequencing analysis and investigated the changes in the mTORC1 signaling pathway. LAT1 ablation resulted in a notable reduction in phosphorylation of p70S6K, a downstream target of mTORC1, as well as its substrate S6RP. This reduced cell proliferation and mTORC1 activity were rescued when LAT1 was overexpressed. These findings imply an essential role of LAT1 for maintenance of tumor cell growth and additional therapeutic angles against liver cancer.

Genetically Programmable Vesicles for Enhancing CAR-T Therapy against Solid Tumors

Chimeric antigen receptor-T (CAR-T) cell therapy has shown remarkable success in eradicating hematologic malignancies; however, its efficacy in treating solid tumors has always been limited due to the presence of an immune-suppressive tumor microenvironment (TME). Here, genetically programmable cellular vesicles expressing high-affinity anti-programmed death-ligand 1 single chain variable fragment (anti-PD-L1 scFv) loaded with glutamine antagonist (D@aPD-L1 NVs) are developed to metabolically dismantle the immunosuppressive TME and enhance the efficiency of anti-mesothelin CAR-T cells in orthotopic lung cancer. As anti-PD-L1 scFv can specifically bind to the programmed death-ligand 1 (PD-L1) on tumor cells, D@aPD-L1 NVs enable the targeted delivery of glutamine antagonists to the tumor site and address the upregulation of PD-L1 on tumor cells, which prevents the premature exhaustion of CAR-T cells. More importantly, D@aPD-L1 NVs effectively reduce the number of immunosuppressive cells and promote the recruitment of inflammatory cells and the secretion of inflammatory cytokines in tumor tissues. These unique features of D@aPD-L1 NVs improve the infiltration and effector functions of CAR-T cells, which ultimately enhance the anti-tumor ability and long-term memory immunity of CAR-T cells. The findings support that D@aPD-L1 NVs act as a promising drug to strengthen the effectiveness of CAR-T cells against solid tumors.

Pancreatic cancer: Advances and challenges

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers. Significant efforts have largely defined major genetic factors driving PDAC pathogenesis and progression. Pancreatic tumors are characterized by a complex microenvironment that orchestrates metabolic alterations and supports a milieu of interactions among various cell types within this niche. In this review, we highlight the foundational studies that have driven our understanding of these processes. We further discuss the recent technological advances that continue to expand our understanding of PDAC complexity. We posit that the clinical translation of these research endeavors will enhance the currently dismal survival rate of this recalcitrant disease.

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.

Regulation of metabolism in pancreatic ductal adenocarcinoma via nanotechnology-enabled strategies

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal malignancy with insidious onset and early distal metastasis. Metabolic reprogramming, the autonomous changes in cellular bioenergetics driven by aberrant genetic events and crosstalk between cancer and non-cancer cells in the desmoplastic microenvironment, is pivotal for the rapid progression of PDAC. As an attractive therapeutic target, nucleoside metabolism is regulated by various anti-metabolic drugs for the clinical treatment of PDAC. Despite various challenges, such as poor drug delivery efficiency and off-target side effects, metabolic modification and intervention are emerging as promising strategies for PDAC therapy, enabled by the rapid development of nanotechnology-based drug delivery strategies. In this review, we discuss the metabolic characteristics of PDAC and highlight how the development of nanomedicine has boosted the development of new therapeutics for PDAC by modulating critical targets in metabolic reprogramming.

Alone and together: current approaches to targeting glutaminase enzymes as part of anti-cancer therapies

Metabolic reprogramming is a major hallmark of malignant transformation in cancer, and part of the so-called Warburg effect, in which the upregulation of glutamine catabolism plays a major role. The glutaminase enzymes convert glutamine to glutamate, which initiates this pathway. Inhibition of different forms of glutaminase (KGA, GAC, or LGA) demonstrated potential as an emerging anti-cancer therapeutic strategy. The regulation of these enzymes, and the molecular basis for their inhibition, have been the focus of much recent research. This review will explore the recent progress in understanding the molecular basis for activation and inhibition of different forms of glutaminase, as well as the recent focus on combination therapies of glutaminase inhibitors with other anti-cancer drugs.

Metabolic Recycling Enhances Proliferation in MYC-Transformed Lymphoma B Cells

Relapses negatively impact cancer patient survival due to the tumorigenesis ability of surviving cancer cells post-therapy. Efforts are needed to better understand and combat this problem. This study hypothesized that dead cell debris post-radiation therapy creates an advantageous microenvironment rich in metabolic materials promoting the growth of remaining live cancer cells. In this study, live cancer cells are co-cultured with dead cancer cells eradicated by UV radiation to mimic a post-therapy environment. Isotopic labeling metabolomics is used to investigate the metabolic behavior of cancer cells grown in a post-radiation-therapy environment. It is found that post-UV-eradicated dead cancer cells serve as nutritional sources of "off-the-shelf" and precursor metabolites for surviving cancer cells. The surviving cancer cells then take up these metabolites, integrate and upregulate multiple vital metabolic processes, thereby significantly increasing growth in vitro and probably in vivo beyond their intrinsic fast-growing characteristics. Importantly, this active metabolite uptake behavior is only observed in oncogenic but not in non-oncogenic cells, presenting opportunities for therapeutic approaches to interrupt the active uptake process of oncogenic cells without affecting normal cells. The process by which living cancer cells re-use vital metabolites released by dead cancer cells post-therapy is coined in this study as "metabolic recycling" of oncogenic cells.

Anticancer Properties of Hexosamine Analogs Designed to Attenuate Metabolic Flux through the Hexosamine Biosynthetic Pathway

Altered cellular metabolism is a hallmark of cancer pathogenesis and progression; for example, a near-universal feature of cancer is increased metabolic flux through the hexosamine biosynthetic pathway (HBP). This pathway produces uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), a potent oncometabolite that drives multiple facets of cancer progression. In this study, we synthesized and evaluated peracetylated hexosamine analogs designed to reduce flux through the HBP. By screening a panel of analogs in pancreatic cancer and glioblastoma multiform (GBM) cells, we identified Ac₄Glc2Bz─a benzyl-modified GlcNAc mimetic─as an antiproliferative cancer drug candidate that down-regulated oncogenic metabolites and reduced GBM cell motility at concentrations non-toxic to non-neoplastic cells. More specifically, the growth inhibitory effects of Ac₄Glc2Bz were linked to reduced levels of UDP-GlcNAc and concomitant decreases in protein O-GlcNAc modification in both pancreatic cancer and GBM cells. Targeted metabolomics analysis in GBM cells showed that Ac₄Glc2Bz disturbed glucose metabolism, amino acid pools, and nucleotide precursor biosynthesis, consistent with reduced proliferation and other anti-oncogenic properties of this analog. Furthermore, Ac₄Glc2Bz reduced the invasion, migration, and stemness of GBM cells. Importantly, normal metabolic functions mediated by UDP-GlcNAc were not disrupted in non-neoplastic cells, including maintenance of endogenous levels of O-GlcNAcylation with no global disruption of N-glycan production. Finally, a pilot in vivo study showed that a potential therapeutic window exists where animals tolerated 5- to 10-fold higher levels of Ac₄Glc2Bz than projected for in vivo efficacy. Together, these results establish GlcNAc analogs targeting the HBP through salvage mechanisms as a new therapeutic approach to safely normalize an important facet of aberrant glucose metabolism associated with cancer.

Histopathologic and proteogenomic heterogeneity reveals features of clear cell renal cell carcinoma aggressiveness

Clear cell renal cell carcinomas (ccRCCs) represent ∼75% of RCC cases and account for most RCC-associated deaths. Inter- and intratumoral heterogeneity (ITH) results in varying prognosis and treatment outcomes. To obtain the most comprehensive profile of ccRCC, we perform integrative histopathologic, proteogenomic, and metabolomic analyses on 305 ccRCC tumor segments and 166 paired adjacent normal tissues from 213 cases. Combining histologic and molecular profiles reveals ITH in 90% of ccRCCs, with 50% demonstrating immune signature heterogeneity. High tumor grade, along with BAP1 mutation, genome instability, increased hypermethylation, and a specific protein glycosylation signature define a high-risk disease subset, where UCHL1 expression displays prognostic value. Single-nuclei RNA sequencing of the adverse sarcomatoid and rhabdoid phenotypes uncover gene signatures and potential insights into tumor evolution. In vitro cell line studies confirm the potential of inhibiting identified phosphoproteome targets. This study molecularly stratifies aggressive histopathologic subtypes that may inform more effective treatment strategies.

Tumor microenvironment-regulating nanomedicine design to fight multi-drug resistant tumors

The tumor microenvironment (TME) is a very cunning system that enables tumor cells to escape death post-traditional antitumor treatments through the comprehensive effect of different factors, thereby leading to drug resistance. Deep insights into TME characteristics and tumor resistance encourage the construction of nanomedicines that can remodel the TME against drug resistance. Tremendous interest in combining TME-regulation measurement with traditional tumor treatment to fight multidrug-resistant tumors has been inspired by the increasing understanding of the role of TME reconstruction in improving the antitumor efficiency of drug-resistant tumor therapy. This review focuses on the underlying relationships between specific TME characteristics (such as hypoxia, acidity, immunity, microorganisms, and metabolism) and drug resistance in tumor treatments. The exciting antitumor activities strengthened by TME regulation are also discussed in-depth, providing solutions from the perspective of nanomedicine design. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Targeting glycolysis for cancer therapy using drug delivery systems

There is close crosstalk between cancer metabolism and immunity. Cancer metabolism regulation is a promising therapeutic target for cancer immunotherapy. Warburg effect is characterized by abnormal glucose metabolism that includes common features of increased glucose uptake and lactate production. The aerobic glycolysis can reprogram the cancer cells and promote the formation of a suppressive immune microenvironment. As a case in point, lactate plays an essential role in tumorigenesis, which is the end product of glycolysis as well as serves as a fuel supporting cancer cell survival. Meanwhile, it is also an important immune regulator that drives immunosuppression in tumors. Immunometabolic therapy is to intervene tumor metabolism and regulate the related metabolites that participate in the innate and acquired immunity, thereby reinstalling the immune balance and eliciting anticancer immune responses. In this contribution to the Orations - New Horizons of the Journal of controlled Release I will provide an overview of glucose metabolism in tumors and its effects on drug resistance and tumor metastasis, and present the advance of glycolysis-targeting therapy strategies with drug delivery techniques, as well as discuss the challenges in glycolysis-targeting immunometabolic therapy.

Effects of metabolic cancer therapy on tumor microenvironment

Targeting tumor metabolism for cancer therapy is an old strategy. In fact, historically the first effective cancer therapeutics were directed at nucleotide metabolism. The spectrum of metabolic drugs considered in cancer increases rapidly - clinical trials are in progress for agents directed at glycolysis, oxidative phosphorylation, glutaminolysis and several others. These pathways are essential for cancer cell proliferation and redox homeostasis, but are also required, to various degrees, in other cell types present in the tumor microenvironment, including immune cells, endothelial cells and fibroblasts. How metabolism-targeted treatments impact these tumor-associated cell types is not fully understood, even though their response may co-determine the overall effectivity of therapy. Indeed, the metabolic dependencies of stromal cells have been overlooked for a long time. Therefore, it is important that metabolic therapy is considered in the context of tumor microenvironment, as understanding the metabolic vulnerabilities of both cancer and stromal cells can guide new treatment concepts and help better understand treatment resistance. In this review we discuss recent findings covering the impact of metabolic interventions on cellular components of the tumor microenvironment and their implications for metabolic cancer therapy.

Therapeutic Targeting of Glutaminolysis as a Novel Strategy to Combat Cancer Stem Cells

Rare subpopulations of cancer stem cells (CSCs) have the ability to self-renew and are the primary driving force behind cancer metastatic dissemination and the preeminent hurdle to cancer treatment. As opposed to differentiated, non-malignant tumor offspring, CSCs have sophisticated metabolic patterns that, depending on the kind of cancer, rely mostly on the oxidation of major fuel substrates such as glucose, glutamine, and fatty acids for survival. Glutaminolysis is a series of metabolic reactions that convert glutamine to glutamate and, eventually, α-ketoglutarate, an intermediate in the tricarboxylic acid (TCA) cycle that provides biosynthetic building blocks. These building blocks are mostly utilized in the synthesis of macromolecules and antioxidants for redox homeostasis. A recent study revealed the cellular and molecular interconnections between glutamine and cancer stemness in the cell. Researchers have increasingly focused on glutamine catabolism in their attempt to discover an effective therapy for cancer stem cells. Targeting catalytic enzymes in glutaminolysis, such as glutaminase (GLS), is achievable with small molecule inhibitors, some of which are in early-phase clinical trials and have promising safety profiles. This review summarizes the current findings in glutaminolysis of CSCs and focuses on novel cancer therapies that target glutaminolysis in CSCs.

Design of Nanoparticles in Cancer Therapy Based on Tumor Microenvironment Properties

Cancer is one of the leading causes of death worldwide, and battling cancer has always been a challenging subject in medical sciences. All over the world, scientists from different fields of study try to gain a deeper knowledge about the biology and roots of cancer and, consequently, provide better strategies to fight against it. During the past few decades, nanoparticles (NPs) have attracted much attention for the delivery of therapeutic and diagnostic agents with high efficiency and reduced side effects in cancer treatment. Targeted and stimuli-sensitive nanoparticles have been widely studied for cancer therapy in recent years, and many more studies are ongoing. This review aims to provide a broad view of different nanoparticle systems with characteristics that allow them to target diverse properties of the tumor microenvironment (TME) from nanoparticles that can be activated and release their cargo due to the specific characteristics of the TME (such as low pH, redox, and hypoxia) to nanoparticles that can target different cellular and molecular targets of the present cell and molecules in the TME.

3-Bromopyruvate inhibits pancreatic tumor growth by stalling glycolysis, and dismantling mitochondria in a syngeneic mouse model

Pancreatic cancer (PC) is the fourth-most-deadly cancer in the United States with a 5-year survival rate of only 8%. The majority of patients with locally advanced pancreatic cancer undergo chemotherapy and/or radiation therapy (RT). However, current treatments are inadequate and novel strategies are desperately required. 3-Bromopyruvate (3-BP) is a promising anticancer drug against pancreatic cancer. It exerts potent anticancer effects by inhibiting hexokinase II enzyme (HK2) of the glycolytic pathway in cancer cells while not affecting the normal cells. 3-BP killed 95% of Panc-2 cells at 15 μM concentration and severely inhibited ATP production by disrupting the interaction between HK2 and mitochondrial Voltage Dependent Anion Channel-1 (VDAC1) protein. Electron microscopy data revealed that 3-BP severely damaged mitochondrial membrane in cancer cells. We further examined therapeutic effect of 3-BP in syngeneic mouse pancreatic cancer model by treating animals with 10, 15 and 20 mg/kg dose. 3-BP at 15 & 20 mg/kg dose level significantly reduced tumor growth by approximately 75-80% in C57BL/6 female mice. Immunohistochemistry data showed complete inhibition of hexokinase II (HK2) and TGFβ, in animals treated with 3-BP drug. We also observed enhanced expression of active caspase-3 in tumor tissues exhibited apoptotic death. Flow Cytometry analysis showed significant inhibition in MDSC (CD11b) population in treated tumor which may have allowed infiltration of CD8+ T cells and inhibited tumor growth. Notably, metabolomic data also revealed severe inhibition in glycolysis, NADP, ATP and lactic acid production in cancer cells treated with 40 μM 3-BP. Importantly, we also observed inhibition in lactic acid production responsible for tumor aggression. These results provide new evidence that 3-BP severely inhibit glucose metabolism in cancer cells by blocking hexokinase II, and disrupting mitochondria by suppressing BCL2L1 in pancreatic cancer.

Differential integrated stress response and asparagine production drive symbiosis and therapy resistance of pancreatic adenocarcinoma cells

The pancreatic tumor microenvironment drives deregulated nutrient availability. Accordingly, pancreatic cancer cells require metabolic adaptations to survive and proliferate. Pancreatic cancer subtypes have been characterized by transcriptional and functional differences, with subtypes reported to exist within the same tumor. However, it remains unclear if this diversity extends to metabolic programming. Here, using metabolomic profiling and functional interrogation of metabolic dependencies, we identify two distinct metabolic subclasses among neoplastic populations within individual human and mouse tumors. Furthermore, these populations are poised for metabolic cross-talk, and in examining this, we find an unexpected role for asparagine supporting proliferation during limited respiration. Constitutive GCN2 activation permits ATF4 signaling in one subtype, driving excess asparagine production. Asparagine release provides resistance during impaired respiration, enabling symbiosis. Functionally, availability of exogenous asparagine during limited respiration indirectly supports maintenance of aspartate pools, a rate-limiting biosynthetic precursor. Conversely, depletion of extracellular asparagine with PEG-asparaginase sensitizes tumors to mitochondrial targeting with phenformin.

Tumor-targeted dual-starvation therapy based on redox-responsive micelle nanosystem with co-loaded LND and BPTES

The starvation therapy mediated by the lonidamine (LND) was limited by the low drug delivery efficiency, off-target effect and compensative glutamine metabolism. Herein, a hyaluronic acid (HA)-modified reduction-responsive micellar nanosystem co-loaded with glycolysis and glutamine metabolism inhibitor (LND and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl)ethyl sulfide, BPTES) was constructed for tumor-targeted dual-starvation therapy. The in vitro and in vivo results collectively suggested that the fabricated nanosystem could effectively endocytosed by tumor cells via HA receptor-ligand recognition, and rapidly release starvation-inducers LND and BPTES in response to the GSH-rich intratumoral cytoplasm. Furthermore, the released LND and BPTES were capable of inducing glycolysis and glutamine metabolism suppression, and accompanied by significant mitochondrial damage, cell cycle arrest and tumor cells apoptosis, eventually devoting to the blockade of the energy and substance supply and tumor killing with high efficiency. In summary, HPPPH@L@B nanosystem significantly inhibited the compensatory glycolysis and glutamine metabolism via the dual-starvation therapy strategy, blocked the indispensable energy and substance supply of tumors, consequently leading to the desired tumor starvation and effective tumor killing with reliable biosafety.

Targeting Glutamine Metabolism to Enhance Immunoprevention of EGFR-Driven Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. Vaccination against EGFR can be one of the venues to prevent lung cancer. Blocking glutamine metabolism has been shown to improve anticancer immunity. Here, the authors report that JHU083, an orally active glutamine antagonist prodrug designed to be preferentially activated in the tumor microenvironment, has potent anticancer effects on EGFR-driven mouse lung tumorigenesis. Lung tumor development is significantly suppressed when treatment with JHU083 is combined with an EGFR peptide vaccine (EVax) than either single treatment. Flow cytometry and single-cell RNA sequencing of the lung tumors reveal that JHU083 increases CD8+ T cell and CD4+ Th1 cell infiltration, while EVax elicits robust Th1 cell-mediated immune responses and protects mice against EGFRL858R mutation-driven lung tumorigenesis. JHU083 treatment decreases immune suppressive cells, including both monocytic- and granulocytic-myeloid-derived suppressor cells, regulatory T cells, and pro-tumor CD4+ Th17 cells in mouse models. Interestingly, Th1 cells are found to robustly upregulate oxidative metabolism and adopt a highly activated and memory-like phenotype upon glutamine inhibition. These results suggest that JHU083 is highly effective against EGFR-driven lung tumorigenesis and promotes an adaptive T cell-mediated tumor-specific immune response that enhances the efficacy of EVax.

Recent nanotechnology advancements to treat multidrug-resistance pancreatic cancer: Pre-clinical and clinical overview

Pancreatic cancer (PC) remains one of the most lethal and incurable forms of cancer and has a poor prognosis. One of the significant therapeutic challenges in PC is multidrug resistance (MDR), a phenomenon in which cancer cells develop resistance toward administered therapy. Development of novel therapeutic platforms that could overcome MDR in PC is crucial for improving therapeutic outcomes. Nanotechnology is emerging as a promising tool to enhance drug efficacy and minimize off-target responses via passive and/or active targeting mechanisms. Over the past decade, tremendous efforts have been made to utilize nanocarriers capable of targeting PC cells while minimizing off-target effects. In this review article, we first give an overview of PC and the major molecular mechanisms of MDR, and then we discuss recent advancements in the development of nanocarriers used to overcome PC drug resistance. In doing so, we explore the developmental stages of this research in both pre-clinical and clinical settings. Lastly, we discuss current challenges and gaps in the literature as well as potential future directions in the field.

Targeting mitochondrial metabolism for precision medicine in cancer

During decades, the research field of cancer metabolism was based on the Warburg effect, described almost one century ago. Lately, the key role of mitochondria in cancer development has been demonstrated. Many mitochondrial pathways including oxidative phosphorylation, fatty acid, glutamine, and one carbon metabolism are altered in tumors, due to mutations in oncogenes and tumor suppressor genes, as well as in metabolic enzymes. This results in metabolic reprogramming that sustains rapid cell proliferation and can lead to an increase in reactive oxygen species used by cancer cells to maintain pro-tumorigenic signaling pathways while avoiding cellular death. The knowledge acquired on the importance of mitochondrial cancer metabolism is now being translated into clinical practice. Detailed genomic, transcriptomic, and metabolomic analysis of tumors are necessary to develop more precise treatments. The successful use of drugs targeting metabolic mitochondrial enzymes has highlighted the potential for their use in precision medicine and many therapeutic candidates are in clinical trials. However, development of efficient personalized drugs has proved challenging and the combination with other strategies such as chemocytotoxic drugs, immunotherapy, and ketogenic or calorie restriction diets is likely necessary to boost their potential. In this review, we summarize the main mitochondrial features, metabolic pathways, and their alterations in different cancer types. We also present an overview of current inhibitors, highlight enzymes that are attractive targets, and discuss challenges with translation of these approaches into clinical practice. The role of mitochondria in cancer is indisputable and presents several attractive targets for both tailored and personalized cancer therapy.

Glutamine Is Required for M1-like Polarization of Macrophages in Response to Mycobacterium tuberculosis Infection

In response to Mycobacterium tuberculosis infection, macrophages mount proinflammatory and antimicrobial responses similar to those observed in M1 macrophages activated by lipopolysaccharide (LPS) and interferon gamma (IFN-γ). A metabolic reprogramming to hypoxia-inducible-factor 1 (HIF-1)-mediated uptake of glucose and its metabolism by glycolysis is required for M1-like polarization, but little is known about other metabolic programs driving the M1-like polarization during infection. We report that glutamine serves as a carbon and nitrogen source for the metabolic reprogramming to M1-like macrophages. Widely targeted metabolite screening identified an association of glutamine and/or glutamate with highly affected metabolic pathways of M1-like macrophages. Moreover, stable isotope-assisted metabolomics of U¹³C glutamine and U¹³C glucose revealed that glutamine, rather than glucose, is catabolized in both the oxidative and reductive tricarboxylic acid (TCA) cycles of M1-like macrophages, thereby generating signaling molecules that include succinate, biosynthetic precursors such as aspartate, and itaconate. U¹⁵N glutamine-tracing metabolomics further revealed participation of glutamine nitrogen in synthesis of intermediates of purine and pyrimidine metabolism plus amino acids, including aspartate. These findings were corroborated by diminished M1 polarization from chemical inhibition of glutaminase (GLS), the key enzyme in the glutaminolysis pathway, and by genetic deletion of GLS in infected macrophages. Thus, the catabolism of glutamine is an integral component of metabolic reprogramming in activating macrophages and it coordinates with elevated cytosolic glycolysis to satisfy the cellular demand for bioenergetic and biosynthetic precursors of M1-like macrophages. Knowledge of these new immunometabolic features of M1-like macrophages should advance the development of host-directed therapies for tuberculosis.

Nanoparticle-based therapeutic strategies targeting major clinical challenges in pancreatic cancer treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers due to its aggressiveness and the challenges for early diagnosis and treatment. Recently, nanotechnology has demonstrated relevant strategies to overcome some of the major clinical issues in the treatment of PDAC. This review is focused on the pathological hallmarks of PDAC and the impact of nanotechnology to find solutions. It describes the use of nanoparticle-based systems designed for the delivery of chemotherapeutic agents and combinatorial alternatives that address the chemoresistance associated with PDAC, the development of combination therapies targeting the molecular heterogeneity in PDAC, the investigation of novel therapies dealing with the improvement of immunotherapy and handling the desmoplastic stroma in PDAC by remodeling the tumor microenvironment. A special section is dedicated to the design of nanoparticles for unique non-traditional modalities that could be promising in the future for the improvement in the dismal prognosis of PDAC.

Emerging Nanotherapeutic Approaches to Overcome Drug Resistance in Cancers with Update on Clinical Trials

A key issue with modern cancer treatments is the emergence of resistance to conventional chemotherapy and molecularly targeted medicines. Cancer nanotherapeutics were created in order to overcome the inherent limitations of traditional chemotherapeutics. Over the last few decades, cancer nanotherapeutics provided unparalleled opportunities to understand and overcome drug resistance through clinical assessment of rationally designed nanoparticulate delivery systems. In this context, various design strategies such as passive targeting, active targeting, nano-drug, and multimodal nano-drug combination therapy provided effective cancer treatment. Even though cancer nanotherapy has made great technological progress, tumor biology complexity and heterogeneity and a lack of comprehensive knowledge of nano-bio interactions remain important roadblocks to future clinical translation and commercialization. The current developments and advancements in cancer nanotherapeutics employing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are discussed in this article. There is also a review of various nanotherapeutics-based approaches to cancer therapy, including targeting strategies for the tumor microenvironment and its components, advanced delivery systems for specific targeting of cancer stem cells (CSC), as well as exosomes for delivery strategies, and an update on clinical trials. Finally, challenges and the future perspective of the cancer nanotherapeutics to reverse cancer drug resistance are discussed.