SNAT7 regulates mTORC1 via macropinocytosis

Crosstalk of glutamine metabolism between cancer-associated fibroblasts and cancer cells

Glutamine (Gln), a critical metabolic substrate, fuels the uncontrolled proliferation of cancer cells. Cancer-associated fibroblasts (CAFs), essential components of the tumor microenvironment, facilitate tumor progression by supplying Gln to cancer cells and driving drug resistance through metabolic reprogramming. This review highlights the key processes of Gln uptake, transport, and catabolism and explores the metabolic crosstalk between CAFs and cancer cells. It also examines the roles of major oncogenic regulators-c-Myc, mTORC, KRAS, p53, and HIF-in controlling Gln metabolism and shaping therapeutic resistance. Current pharmacological approaches targeting Gln metabolism, including enzyme inhibitors and transporter blockers, are discussed alongside emerging therapeutic strategies and ongoing clinical trials. Lastly, we underscore the importance of integrating advanced technologies like artificial intelligence and spatial omics to refine treatment targeting and develop more effective, personalized therapeutic interventions.

Liquid crystal monomers induce placental development and progesterone release dysregulation through transplacental transportation

Embryonic and fetal development can be affected during gestation by exposure to xenobiotics that cross the placenta. Liquid crystal monomers (LCMs) are emerging contaminants commonly found in indoor environments; however, whether they can cross the placenta and affect placental development remains unexplored. Here, we develop an evaluation system that integrates human biomonitoring, uterine perfusion in pregnant rats, and placental cells. We find fourteen out of the fifty-six LCMs that are detected in maternal and cord serum samples from ninety-three healthy pregnant women, at median levels of 13.9 and 18.1 ng/mL, respectively. Subsequent explorations of in utero exposure in rats indicate that aromatic amino acid transporter 1 (SLC16A10) mediates transplacental transportation of the LCMs. Placental cells exposed to LCMs exhibit delayed placental development and reduced progesterone release. These findings show that SLC16A10-mediated transplacental transportation of LCMs inhibits placental development and progesterone release, highlighting the importance of gestational exposure to emerging contaminants.

N6-methyladenosine modification of SLC38A7 promotes cell migration, invasion, oxidative phosphorylation, and mitochondrial function in gastric cancer

Solute carrier (SLC) 38 family, responsible for trans-membrane transport of neutral amino acids, plays a role in the proliferation, invasion, and metastasis of cancer cells, but its role in gastric cancer (GC) progression remains unclear. This study aimed to explore the biological effects of SLC38A7 and its regulatory mechanisms in GC. RNA expression data, tumor tissue specimens, and GC cell lines were used for bioinformatics and experimental analyses. Cell Counting Kit-8 assay, wound healing assay, and Transwell invasion assay were used to evaluate cell viability, migration, and invasion, respectively. Oxidative phosphorylation, mitochondrial membrane potential, and expression of the critical proteins in the mitochondrial respiratory chain were assayed using extracellular flux analysis, flow cytometry, and Western blot, respectively. RNA immunoprecipitation assay was used to explore the mechanisms of N6-methyladenosine (m6A) methylation. SLC38A7 was upregulated in GC tissue and cell lines. SLC38A7 silencing suppressed cell viability, migration, invasion, oxidative phosphorylation, and mitochondrial function in cancer cells. SLC38A7 overexpression had the opposite biological effects. Interactions between SLC38A7 and methyltransferase like 3 (METTL3) or insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) were detected. SLC38A7 mRNA stability was maintained by METTL3-IGF2BP2 axis in an m6A-dependent manner. Our results suggest that SLC38A7, stabilized by METTL3 and IGF2BP2-mediated m6A methylation, enhances cell viability, migration, invasion, oxidative phosphorylation, and mitochondrial function in GC, highlighting its role as a potential therapeutic target for GC.

Glutamine transporters as effective targets in digestive system malignant tumor treatment

Glutamine is one of the most abundant non-essential amino acids in human plasma and plays a crucial role in many biological processes of the human body. Tumor cells take up a large amount of glutamine to meet their rapid proliferation requirements, which is supported by the upregulation of glutamine transporters. Targeted inhibition of glutamine transporters effectively inhibits cell growth and proliferation in tumors. Among all cancers, digestive system malignant tumors (DSMTs) have the highest incidence and mortality rates, and the current therapeutic strategies for DSMTs are mainly surgical resection and chemotherapy. Due to the relatively low survival rate and severe side effects associated with DSMTs treatment, new treatment strategies are urgently required. This article summarizes the glutamine transporters involved in DSMTs and describes their role in DSMTs. Additionally, glutamine transporter-target drugs are discussed, providing theoretical guidance for the further development of drugs DSMTs treatment.

The role of lysosomal membrane proteins in autophagy and related diseases

As a self-degrading and highly conserved survival mechanism, autophagy plays an important role in maintaining cell survival and recycling. The discovery of autophagy-related (ATG) genes has revolutionized our understanding of autophagy. Lysosomal membrane proteins (LMPs) are important executors of lysosomal function, and increasing evidence has demonstrated their role in the induction and regulation of autophagy. In addition, the functional dysregulation of the process mediated by LMPs at all stages of autophagy is closely related to neurodegenerative diseases and cancer. Here, we review the role of LMPs in autophagy, focusing on their roles in vesicle nucleation, vesicle elongation and completion, the fusion of autophagosomes and lysosomes, and degradation, as well as their broad association with related diseases.

Asparagine: A key metabolic junction in targeted tumor therapy

Nutrient bioavailability in the tumor microenvironment plays a pivotal role in tumor proliferation and metastasis. Among these nutrients, glutamine is a key substance that promotes tumor growth and proliferation, and its downstream metabolite asparagine is also crucial in tumors. Studies have shown that when glutamine is exhausted, tumor cells can rely on asparagine to sustain their growth. Given the reliance of tumor cell proliferation on asparagine, restricting its bioavailability has emerged as promising strategy in cancer treatment. For instance, the use of asparaginase, an enzyme that depletes asparagine, has been one of the key chemotherapies for acute lymphoblastic leukemia (ALL). However, tumor cells can adapt to asparagine restriction, leading to reduced chemotherapy efficacy, and the mechanisms by which different genetically altered tumors are sensitized or adapted to asparagine restriction vary. We review the sources of asparagine and explore how limiting its bioavailability impacts the progression of specific genetically altered tumors. It is hoped that by targeting the signaling pathways involved in tumor adaptation to asparagine restriction and certain factors within these pathways, the issue of drug resistance can be addressed. Importantly, these strategies offer precise therapeutic approaches for genetically altered cancers.

Chlorogenic acid enhances PPARγ-mediated lipogenesis through preventing Lipin 1 nuclear translocation in Staphylococcus aureus-exposed bovine mammary epithelial cells

Chlorogenic acid (CGA) as one of the most ubiquitously dietary polyphenolic compounds, has been reported to have various antimicrobial effects and exhibit strong anti-inflammatory ability. Staphylococcus aureus is a gram-positive bacterium that can induce mastitis. However, the mechanism through which S. aureus infection affects lipid synthesis and whether CGA have protective effect on S. aureus reduced lipid synthesis is not fully understood. In this study, the internalization of S. aureus reduced intracellular lipid droplet formation, decreased the levels of intracellular triacylglycerol, total cholesterol and 7 types of fatty acid and downregulated the expression of lipogenic genes FAS, ACC, and DGAT1 in bovine mammary epithelial cells (BMECs). In addition, we found that S. aureus intracellular infection attenuated mTORC1 activation resulting in Lipin 1 nuclear localization. Remarkablely, S. aureus infection-mediated repression of lipid synthesis related to the mTORC1 signaling and Lipin 1 nuclear localization can be alleviated by CGA. Thus, our findings provide a novel mechanism by which lipid synthesis is regulated under S. aureus infection and the protective effects of CGA on lipid synthesis in BMECs.

The role of amino acid metabolism alterations in pancreatic cancer: From mechanism to application

The incidence of pancreatic cancer is increasing in both developed and developing Nations. In recent years, various research evidence suggested that reprogrammed metabolism may play a key role in pancreatic cancer tumorigenesis and development. Therefore, it has great potential as a diagnostic, prognostic and therapeutic target. Amino acid metabolism is deregulated in pancreatic cancer, and changes in amino acid metabolism can affect cancer cell status, systemic metabolism in malignant tumor patients and mistakenly involved in different biological processes including stemness, proliferation and growth, invasion and migration, redox state maintenance, autophagy, apoptosis and even tumor microenvironment interaction. Generally, the above effects are achieved through two pathways, energy metabolism and signal transduction. This review aims to highlight the current research progress on the abnormal alterations of amino acids metabolism in pancreatic cancer, how they affect tumorigenesis and development of pancreatic cancer and the application prospects of them as diagnostic, prognostic and therapeutic targets.

Regulation of mTORC1 by the Rag GTPases

The Rag GTPases are an evolutionarily conserved family that play a crucial role in amino acid sensing by the mammalian target of rapamycin complex 1 (mTORC1). mTORC1 is often referred to as the master regulator of cell growth. mTORC1 hyperactivation is observed in multiple diseases such as cancer, obesity, metabolic disorders, and neurodegeneration. The Rag GTPases sense amino acid levels and form heterodimers, where RagA or RagB binds to RagC or RagD, to recruit mTORC1 to the lysosome where it becomes activated. Here, we review amino acid signaling to mTORC1 through the Rag GTPases.

Insights of Endocytosis Signaling in Health and Disease

Endocytosis in mammalian cells is a fundamental cellular machinery that regulates vital physiological processes, such as the absorption of metabolites, release of neurotransmitters, uptake of hormone cellular defense, and delivery of biomolecules across the plasma membrane. A remarkable characteristic of the endocytic machinery is the sequential assembly of the complex proteins at the plasma membrane, followed by internalization and fusion of various biomolecules to different cellular compartments. In all eukaryotic cells, functional characterization of endocytic pathways is based on dynamics of the protein complex and signal transduction modules. To coordinate the assembly and functions of the numerous parts of the endocytic machinery, the endocytic proteins interact significantly within and between the modules. Clathrin-dependent and -independent endocytosis, caveolar pathway, and receptor mediated endocytosis have been attributed to a greater variety of physiological and pathophysiological roles such as, autophagy, metabolism, cell division, apoptosis, cellular defense, and intestinal permeabilization. Notably, any defect or alteration in the endocytic machinery results in the development of pathological consequences associated with human diseases such as cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. In this review, an in-depth endeavor has been made to illustrate the process of endocytosis, and associated mechanisms describing pathological manifestation associated with dysregulated endocytosis machinery.

Control of tumor-associated macrophage responses by nutrient acquisition and metabolism

Metazoan tissue specification is associated with integration of macrophage lineage cells in sub-tissular niches to promote tissue development and homeostasis. Oncogenic transformation, most prevalently of epithelial cell lineages, results in maladaptation of resident tissue macrophage differentiation pathways to generate parenchymal and interstitial tumor-associated macrophages that largely foster cancer progression. In addition to growth factors, nutrients that can be consumed, stored, recycled, or converted to signaling molecules have emerged as crucial regulators of macrophage responses in tumor. Here, we review how nutrient acquisition through plasma membrane transporters and engulfment pathways control tumor-associated macrophage differentiation and function. We also discuss how nutrient metabolism regulates tumor-associated macrophages and how these processes may be targeted for cancer therapy.

ATM inhibition drives metabolic adaptation via induction of macropinocytosis

Macropinocytosis is a nonspecific endocytic process that may enhance cancer cell survival under nutrient-poor conditions. Ataxia-Telangiectasia mutated (ATM) is a tumor suppressor that has been previously shown to play a role in cellular metabolic reprogramming. We report that the suppression of ATM increases macropinocytosis to promote cancer cell survival in nutrient-poor conditions. Combined inhibition of ATM and macropinocytosis suppressed proliferation and induced cell death both in vitro and in vivo. Supplementation of ATM-inhibited cells with amino acids, branched-chain amino acids (BCAAs) in particular, abrogated macropinocytosis. Analysis of ATM-inhibited cells in vitro demonstrated increased BCAA uptake, and metabolomics of ascites and interstitial fluid from tumors indicated decreased BCAAs in the microenvironment of ATM-inhibited tumors. These data reveal a novel basis of ATM-mediated tumor suppression whereby loss of ATM stimulates protumorigenic uptake of nutrients in part via macropinocytosis to promote cancer cell survival and reveal a potential metabolic vulnerability of ATM-inhibited cells.