The creatine-phosphagen system is mechanoresponsive in pancreatic adenocarcinoma and fuels invasion and metastasis

Extracellular matrix stiffness: mechanisms in tumor progression and therapeutic potential in cancer

Tumor microenvironment (TME) is a complex ecosystem composed of both cellular and non-cellular components that surround tumor tissue. The extracellular matrix (ECM) is a key component of the TME, performing multiple essential functions by providing mechanical support, shaping the TME, regulating metabolism and signaling, and modulating immune responses, all of which profoundly influence cell behavior. The quantity and cross-linking status of stromal components are primary determinants of tissue stiffness. During tumor development, ECM stiffness not only serves as a barrier to hinder drug delivery but also promotes cancer progression by inducing mechanical stimulation that activates cell membrane receptors and mechanical sensors. Thus, a comprehensive understanding of how ECM stiffness regulates tumor progression is crucial for identifying potential therapeutic targets for cancer. This review examines the effects of ECM stiffness on tumor progression, encompassing proliferation, migration, metastasis, drug resistance, angiogenesis, epithelial-mesenchymal transition (EMT), immune evasion, stemness, metabolic reprogramming, and genomic stability. Finally, we explore therapeutic strategies that target ECM stiffness and their implications for tumor progression.

The (un)known crosstalk between metabolism and mechanotransduction: Implications for metabolic syndrome (MetS)-associated neurological complications

Metabolic syndrome (MetS) has been associated with disruptions in tissue mechanical homeostasis and inflammatory and metabolic derangements. However, the direct correlation between metabolic alterations and changes in tissue stiffness, and whether they could play a role as upstream initiators of disease pathology remains to be investigated. This emerging concept has yet to be put into clinical practice as many questions concerning the interplay between extracellular matrix mechanical properties and regulation of metabolic pathways remain unsolved. This review will highlight key foundational studies examining mutual regulation of cell metabolism and mechanotransduction, and opening questions lying ahead for better understanding MetS pathophysiology.

Arginine: at the crossroads of nitrogen metabolism

L-arginine is the most nitrogen-rich amino acid, acting as a key precursor for the synthesis of nitrogen-containing metabolites and an essential intermediate in the clearance of excess nitrogen. Arginine's side chain possesses a guanidino group which has unique biochemical properties, and plays a primary role in nitrogen excretion (urea), cellular signaling (nitric oxide) and energy buffering (phosphocreatine). The post-translational modification of protein-incorporated arginine by guanidino-group methylation also contributes to epigenetic gene control. Most human cells do not synthesize sufficient arginine to meet demand and are dependent on exogenous arginine. Thus, dietary arginine plays an important role in maintaining health, particularly upon physiologic stress. How cells adapt to changes in extracellular arginine availability is unclear, mostly because nearly all tissue culture media are supplemented with supraphysiologic levels of arginine. Evidence is emerging that arginine-deficiency can influence disease progression. Here, we review new insights into the importance of arginine as a metabolite, emphasizing the central role of mitochondria in arginine synthesis/catabolism and the recent discovery that arginine can act as a signaling molecule regulating gene expression and organelle dynamics.

A glucose-enriched lung pre-metastatic niche triggered by matrix stiffness-tuned exosomal miRNAs in hepatocellular carcinoma

Apart from the classic features, it is almost unknown whether there exist other new pathological features during pre-metastatic niche formation in hepatocellular carcinoma (HCC). Our previous works have highlighted the contribution of increased matrix stiffness to lung pre-metastatic niche formation and metastasis in HCC. However, whether increased matrix stiffness influences glucose metabolism and supply of lung pre-metastatic niche remains largely unclear. Here we uncover the underlying mechanism by which matrix stiffness-tuned exosomal miRNAs as the major contributor modulate glucose enrichment during lung pre-metastatic niche formation through decreasing the glucose uptake and consumption of lung fibroblasts and increasing angiogenesis and vascular permeability. Our findings suggest that glucose enrichment, a new characteristic of the lung pre-metastatic niche triggered by matrix stiffness-tuned exosomal miRNAs, is essential for the colonization and survival of metastatic tumor cells, as well as subsequent metastatic foci growth.

The hidden potential of solasonine: Targeting non-small cell lung cancer (NSCLC) metastasis through GATM and Smad2 pathways

PURPOSE

To study the pharmacological effects of solasonine (Sol) in inhibiting non-small cell lung cancer (NSCLC) metastasis.

METHODS

The pharmacological effects of solasonine were examined in vitro by continuous induction of NSCLC cells by no treatment, or TGF-β, or creatine. Cell migration and invasion were assessed via wound healing and transwell assays, and the levels of epithelial-mesenchymal transition (EMT) markers were determined using immunofluorescence and Western Blot. Solasonine's ability to bind to TGF-β and creatine transferases and isoenzymes was assessed by TCGA, KMPLOT database, cellular thermal shift assay (CETSA), and molecular docking assay. In vivo, two types of NSCLC cells were injected into mice using the tail vein. Solasonine's effect on tumor metastasis was determined using in vivo fluorescent probes, hematoxylin-eosin staining assay, and immunofluorescence.

RESULTS

Unlike traditional therapies targeting TGF-β receptors, Sol was shown to inhibit NSCLC metastasis through a novel mechanism independent of TGF-β signaling. Creatine was found to promote NSCLC metastasis in vitro by enhancing cell migration, invasion, and EMT-related protein expression, and in vivo by increasing metastasis to the liver. These effects were mediated by the activation of Smad2 phosphorylation and EMT independently of TGF-β. Sol effectively counteracted these effects by targeting guanidinoacetate methyltransferase (GATM) with high binding affinity, thereby suppressing the TTK-mediated Smad2 pathway and significantly reducing metastasis to the lungs and liver, as confirmed by HE staining and fluorescence imaging.

CONCLUSIONS

This study identifies solasonine as a novel inhibitor of NSCLC metastasis, acting through the GATM and Smad2 pathways to counter creatine-induced metastasis. These findings underscore the potential of Sol as a therapeutic candidate for metastatic NSCLC.

Mechano-dependent sorbitol accumulation supports biomolecular condensate

Condensed droplets of protein regulate many cellular functions, yet the physiological conditions regulating their formation remain largely unexplored. Increasing our understanding of these mechanisms is paramount, as failure to control condensate formation and dynamics can lead to many diseases. Here, we provide evidence that matrix stiffening promotes biomolecular condensation in vivo. We demonstrate that the extracellular matrix links mechanical cues with the control of glucose metabolism to sorbitol. In turn, sorbitol acts as a natural crowding agent to promote biomolecular condensation. Using in silico simulations and in vitro assays, we establish that variations in the physiological range of sorbitol concentrations, but not glucose concentrations, are sufficient to regulate biomolecular condensates. Accordingly, pharmacological and genetic manipulation of intracellular sorbitol concentration modulates biomolecular condensates in breast cancer-a mechano-dependent disease. We propose that sorbitol is a mechanosensitive metabolite enabling protein condensation to control mechano-regulated cellular functions.

Insights into the mechanisms, regulation, and therapeutic implications of extracellular matrix stiffness in cancer

The tumor microenvironment (TME) is critical for cancer initiation, growth, metastasis, and therapeutic resistance. The extracellular matrix (ECM) is a significant tumor component that serves various functions, including mechanical support, TME regulation, and signal molecule generation. The quantity and cross-linking status of ECM components are crucial factors in tumor development, as they determine tissue stiffness and the interaction between stiff TME and cancer cells, resulting in aberrant mechanotransduction, proliferation, migration, invasion, angiogenesis, immune evasion, and treatment resistance. Therefore, broad knowledge of ECM dysregulation in the TME might aid in developing innovative cancer therapies. This review summarized the available information on major ECM components, their functions, factors that increase and decrease matrix stiffness, and related signaling pathways that interplay between cancer cells and the ECM in TME. Moreover, mechanotransduction alters during tumorogenesis, and current drug therapy based on ECM as targets, as well as future efforts in ECM and cancer, are also discussed.

It Is Not Just About Storing Energy: The Multifaceted Role of Creatine Metabolism on Cancer Biology and Immunology

Creatine, a naturally occurring compound in mammals, is crucial in energy metabolism, particularly within muscle and brain tissues. While creatine metabolism in cancer has been studied for several decades, emerging studies are beginning to clarify the sometimes-contradictory role creatine has in either the promotion or inhibition of cancer. On one hand, creatine can directly enhance anti-tumor CD8+ T-cell activity and induce tumor apoptosis, contributing to antitumor immunity. Conversely, other studies have shown that creatine can facilitate cancer cell growth and migration by providing an energy source and activating several signaling pathways. This review will examine what is known about creatine in cancer biology, with a focus on understanding its roles across different cellular compartments. Lastly, we discuss the emerging roles of creatine metabolism, providing exciting new insights into this often-overlooked pathway. This review highlights the complex role of creatine in cancer development and treatment, offering insights into its potential as both a therapeutic target and a risk factor in oncogenesis.

Tension directs cancer cell migration over fiber alignment through energy minimization

Cell migration during many fundamental biological processes including metastasis requires cells to traverse tissue with heterogeneous mechanical cues that direct migration as well as determine force and energy requirements for motility. However, the influence of discrete structural and mechanical cues on migration remains challenging to determine as they are often coupled. Here, we decouple the pro-invasive cues of collagen fiber alignment and tension to study their individual impact on migration. When presented with both cues, cells preferentially travel in the axis of tension against fiber alignment. Computational and experimental data show applying tension perpendicular to alignment increases potential energy stored within collagen fibers, lowering requirements for cell-induced matrix deformation and energy usage during migration compared to motility in the direction of fiber alignment. Energy minimization directs migration trajectory, and tension can facilitate migration against fiber alignment. These findings provide a conceptual understanding of bioenergetics during migration through a fibrous matrix.

Mitochondrial mechanotransduction through MIEF1 coordinates the nuclear response to forces

Tissue-scale architecture and mechanical properties instruct cell behaviour under physiological and diseased conditions, but our understanding of the underlying mechanisms remains fragmentary. Here we show that extracellular matrix stiffness, spatial confinements and applied forces, including stretching of mouse skin, regulate mitochondrial dynamics. Actomyosin tension promotes the phosphorylation of mitochondrial elongation factor 1 (MIEF1), limiting the recruitment of dynamin-related protein 1 (DRP1) at mitochondria, as well as peri-mitochondrial F-actin formation and mitochondrial fission. Strikingly, mitochondrial fission is also a general mechanotransduction mechanism. Indeed, we found that DRP1- and MIEF1/2-dependent fission is required and sufficient to regulate three transcription factors of broad relevance-YAP/TAZ, SREBP1/2 and NRF2-to control cell proliferation, lipogenesis, antioxidant metabolism, chemotherapy resistance and adipocyte differentiation in response to mechanical cues. This extends to the mouse liver, where DRP1 regulates hepatocyte proliferation and identity-hallmark YAP-dependent phenotypes. We propose that mitochondria fulfil a unifying signalling function by which the mechanical tissue microenvironment coordinates complementary cell functions.

Hydrogel models of pancreatic adenocarcinoma to study cell mechanosensing

Pancreatic adenocarcinoma (PDAC) is the predominant form of pancreatic cancer and one of the leading causes of cancer-related death worldwide, with an extremely poor prognosis after diagnosis. High mortality from PDAC arises partly due to late diagnosis resulting from a lack of early-stage biomarkers and due to chemotherapeutic drug resistance, which arises from a highly fibrotic stromal response known as desmoplasia. Desmoplasia alters tissue mechanics, which triggers changes in cell mechanosensing and leads to dysregulated transcriptional activity and disease phenotypes. Hydrogels are effective in vitro models to mimic mechanical changes in tissue mechanics during PDAC progression and to study the influence of these changes on mechanosensitive cell responses. Despite the complex biophysical changes that occur within the PDAC microenvironment, carefully designed hydrogels can very closely recapitulate these properties during PDAC progression. Hydrogels are relatively inexpensive, highly reproducible and can be designed in a humanised manner to increase their relevance for human PDAC studies. In vivo models have some limitations, including species-species differences, high variability, expense and legal/ethical considerations, which make hydrogel models a promising alternative. Here, we comprehensively review recent advancements in hydrogel bioengineering for developing our fundamental understanding of mechanobiology in PDAC, which is critical for informing advanced therapeutics.

Selective metabolic regulations by p53 mutant variants in pancreatic cancer

BACKGROUND

Approximately half of all human cancers harbour mutations in the p53 gene, leading to the generation of neomorphic p53 mutant proteins. These mutants can exert gain-of-function (GOF) effects, potentially promoting tumour progression. However, the clinical significance of p53 GOF mutations, as well as the selectivity of individual variants, remains controversial and unclear.

METHODS

To elucidate the metabolic regulations and molecular underpinnings associated with the specific p53R270H and p53R172H mutant variants (the mouse equivalents of human p53R273H and p53R175H, respectively), we employed a comprehensive approach. This included integrating global metabolomic analysis with epigenomic and transcriptomic profiling in mouse pancreatic cancer cells. Additionally, we assessed metabolic parameters such as oxygen consumption rate and conducted analyses of proliferation and cell-cell competition to validate the biological impact of metabolic changes on pancreatic ductal adenocarcinoma (PDAC) phenotype. Our findings were further corroborated through analysis of clinical datasets from human cancer cohorts.

RESULTS

Our investigation revealed that the p53R270H variant, but not p53R172H, sustains mitochondrial function and energy production while also influencing cellular antioxidant capacity. Conversely, p53R172H, while not affecting mitochondrial metabolism, attenuates the activation of pro-tumorigenic metabolic pathways such as the urea cycle. Thus, the two variants selectively control different metabolic pathways in pancreatic cancer cells. Mechanistically, p53R270H induces alterations in the expression of genes associated with oxidative stress and reduction in mitochondrial respiration. In contrast, p53R172H specifically impacts the expression levels of enzymes involved in the urea metabolism. However, our analysis of cell proliferation and cell competition suggested that the expression of either p53R270H or p53R172H does not influence confer any selective advantage to this cellular model in vitro. Furthermore, assessment of mitochondrial priming indicated that the p53R270H-driven mitochondrial effect does not alter cytochrome c release or the apoptotic propensity of pancreatic cancer cells.

CONCLUSIONS

Our study elucidates the mutant-specific impact of p53R270H and p53R172H on metabolism of PDAC cancer cells, highlighting the need to shift from viewing p53 mutant variants as a homogeneous group of entities to a systematic assessment of each specific p53 mutant protein. Moreover, our finding underscores the importance of further exploring the significance of p53 mutant proteins using models that more accurately reflect tumor ecology.

Compressive stresses in cancer: characterization and implications for tumour progression and treatment

Beyond their many well-established biological aberrations, solid tumours create an abnormal physical microenvironment that fuels cancer progression and confers treatment resistance. Mechanical forces impact tumours across a range of biological sizes and timescales, from rapid events at the molecular level involved in their sensing and transmission, to slower and larger-scale events, including clonal selection, epigenetic changes, cell invasion, metastasis and immune response. Owing to challenges with studying these dynamic stimuli in biological systems, the mechanistic understanding of the effects and pathways triggered by abnormally elevated mechanical forces remains elusive, despite clear correlations with cancer pathophysiology, aggressiveness and therapeutic resistance. In this Review, we examine the emerging and diverse roles of physical forces in solid tumours and provide a comprehensive framework for understanding solid stress mechanobiology. We first review the physiological importance of mechanical forces, especially compressive stresses, and discuss their defining characteristics, biological context and relative magnitudes. We then explain how abnormal compressive stresses emerge in tumours and describe the experimental challenges in investigating these mechanically induced processes. Finally, we discuss the clinical translation of mechanotherapeutics that alleviate solid stresses and their potential to synergize with chemotherapy, radiotherapy and immunotherapies.

Clinical applications of phosphocreatine and related mechanisms

Phosphocreatine (PCr), a naturally occurring creatine phosphorylated molecule, is a high-energy phosphate compound that is one of the most important substances involved in cell energy metabolism, and also has anti-apoptosis and anti-oxidative stress effects. It is precisely because of its role in maintaining energy homeostasis that PCr is widely used in diseases related to energy damage. In the regulation of cell signal, PCr mainly plays a role through MAPK, NF-κB, PI3K/AKT, ERK/Nrf2/HO-1 and JAK2/STAT3. In clinical applications, PCr is commonly used as a cardioprotective drug, such as ischemic heart disease, myocardial fibrosis, myocardial infarction, arrhythmia, and myocarditis. In recent years, further research on PCr has found that PCr also has a positive role in the treatment of other diseases, including diabetes-induced liver injury, kidney injury, cerebral ischemia-reperfusion injury, and neurodegenerative diseases. In this paper, the literature on PCr in three databases, Web of Sciences, SciFinder, and PubMed, was summarized and analyzed, and the research progress of PCr in recent years was reviewed, hoping to provide help for the expansion of its application in clinical therapy.

Scar/WAVE drives actin protrusions independently of its VCA domain using proline-rich domains

Cell migration requires the constant modification of cellular shape by reorganization of the actin cytoskeleton. Fine-tuning of this process is critical to ensure new actin filaments are formed only at specific times and in defined regions of the cell. The Scar/WAVE complex is the main catalyst of pseudopod and lamellipodium formation during cell migration. It is a pentameric complex highly conserved through eukaryotic evolution and composed of Scar/WAVE, Abi, Nap1/NCKAP1, Pir121/CYFIP, and HSPC300/Brk1. Its function is usually attributed to activation of the Arp2/3 complex through Scar/WAVE's VCA domain, while other parts of the complex are expected to mediate spatial-temporal regulation and have no direct role in actin polymerization. Here, we show in both B16-F1 mouse melanoma and Dictyostelium discoideum cells that Scar/WAVE without its VCA domain still induces the formation of morphologically normal, actin-rich protrusions, extending at comparable speeds despite a drastic reduction of Arp2/3 recruitment. However, the proline-rich regions in Scar/WAVE and Abi subunits are essential, though either is sufficient for the generation of actin protrusions in B16-F1 cells. We further demonstrate that N-WASP can compensate for the absence of Scar/WAVE's VCA domain and induce lamellipodia formation, but it still requires an intact WAVE complex, even if without its VCA domain. We conclude that the Scar/WAVE complex does more than directly activating Arp2/3, with proline-rich domains playing a central role in promoting actin protrusions. This implies a broader function for the Scar/WAVE complex, concentrating and simultaneously activating many actin-regulating proteins as a lamellipodium-producing core.

Lipid synthesis leads the way for invasive migration

Invasive migration requires cells to break through extracellular matrix barriers, which is an energy-expensive process. In this issue, Park et al. (https://doi.org/10.1083/jcb.202402035) highlight the importance of biosynthesis of fatty acids, phospholipids, and isoprenoids in driving invasive migration of the Caenorhabditis elegans anchor cell through a basement membrane barrier during development.

A covalent creatine kinase inhibitor ablates glioblastoma migration and sensitizes tumors to oxidative stress

Glioblastoma is a Grade 4 primary brain tumor defined by therapy resistance, diffuse infiltration, and near-uniform lethality. The underlying mechanisms are unknown, and no treatment has been curative. Using a recently developed creatine kinase inhibitor (CKi), we explored the role of this inhibitor on GBM biology in vitro. While CKi minimally impacted GBM cell proliferation and viability, it significantly affected migration. In established GBM cell lines and patient-derived xenografts, CKi ablated both the migration and invasion of GBM cells. CKi also hindered radiation-induced migration. RNA-seq revealed a decrease in invasion-related genes, with an unexpected increase in glutathione metabolism and ferroptosis protection genes post-CKi treatment. The effects of CKi could be reversed by the addition of cell-permeable glutathione. Carbon-13 metabolite tracing indicated heightened glutathione biosynthesis post-CKi treatment. Combinatorial CKi blockade and glutathione inhibition or ferroptosis activation abrogated cell survival. Our data demonstrated that CKi perturbs promigratory and anti-ferroptotic roles in GBM, identifying the creatine kinase axis as a druggable target for GBM treatment.

The role and mechanism of compressive stress in tumor

Recent research has revealed the important role of mechanical forces in the initiation and progression of tumors. The interplay between mechanical and biochemical cues affects the function and behavior of tumor cells during the development of solid tumors, especially their metastatic potential. The compression force generated by excessive cell proliferation and the tumor microenvironment widely regulates the progression of solid tumor disease. Tumor cells can sense alterations in compressive stress through diverse mechanosensitive components and adapt their mechanical characteristics accordingly to adapt to environmental changes. Here, we summarize the current role of compressive stress in regulating tumor behavior and its biophysical mechanism from the mechanobiological direction.

Phosphocreatine Promotes Epigenetic Reprogramming to Facilitate Glioblastoma Growth Through Stabilizing BRD2

Glioblastoma (GBM) exhibits profound metabolic plasticity for survival and therapeutic resistance, while the underlying mechanisms remain unclear. Here, we show that GBM stem cells reprogram the epigenetic landscape by producing substantial amounts of phosphocreatine (PCr). This production is attributed to the elevated transcription of brain-type creatine kinase, mediated by Zinc finger E-box binding homeobox 1. PCr inhibits the poly-ubiquitination of the chromatin regulator bromodomain containing protein 2 (BRD2) by outcompeting the E3 ubiquitin ligase SPOP for BRD2 binding. Pharmacological disruption of PCr biosynthesis by cyclocreatine (cCr) leads to BRD2 degradation and a decrease in its targets' transcription, which inhibits chromosome segregation and cell proliferation. Notably, cyclocreatine treatment significantly impedes tumor growth and sensitizes tumors to a BRD2 inhibitor in mouse GBM models without detectable side effects. These findings highlight that high production of PCr is a druggable metabolic feature of GBM and a promising therapeutic target for GBM treatment. Significance: Glioblastoma (GBM) exhibits an adaptable metabolism crucial for survival and therapy resistance. We demonstrate that GBM stem cells modify their epigenetics by producing phosphocreatine (PCr), which prevents bromodomain containing protein 2 (BRD2) degradation and promotes accurate chromosome segregation. Disrupting PCr biosynthesis impedes tumor growth and improves the efficacy of BRD2 inhibitors in mouse GBM models.

The lncRNA LINC01605 promotes the progression of pancreatic ductal adenocarcinoma by activating the mTOR signaling pathway

BACKGROUND

This study investigated the molecular mechanism of long intergenic non-protein coding RNA 1605 (LINC01605) in the process of tumor growth and liver metastasis of pancreatic ductal adenocarcinoma (PDAC).

METHODS

LINC01605 was filtered out with specificity through TCGA datasets (related to DFS) and our RNA-sequencing data of PDAC tissue samples from Renji Hospital. The expression level and clinical relevance of LINC01605 were then verified in clinical cohorts and samples by immunohistochemical staining assay and survival analysis. Loss- and gain-of-function experiments were performed to estimate the regulatory effects of LINC01605 in vitro. RNA-seq of LINC01605-knockdown PDAC cells and subsequent inhibitor-based cellular function, western blotting, immunofluorescence and rescue experiments were conducted to explore the mechanisms by which LINC01605 regulates the behaviors of PDAC tumor cells. Subcutaneous xenograft models and intrasplenic liver metastasis models were employed to study its role in PDAC tumor growth and liver metastasis in vivo.

RESULTS

LINC01605 expression is upregulated in both PDAC primary tumor and liver metastasis tissues and correlates with poor clinical prognosis. Loss and gain of function experiments in cells demonstrated that LINC01605 promotes the proliferation and migration of PDAC cells in vitro. In subsequent verification experiments, we found that LINC01605 contributes to PDAC progression through cholesterol metabolism regulation in a LIN28B-interacting manner by activating the mTOR signaling pathway. Furthermore, the animal models showed that LINC01605 facilitates the proliferation and metastatic invasion of PDAC cells in vivo.

CONCLUSIONS

Our results indicate that the upregulated lncRNA LINC01605 promotes PDAC tumor cell proliferation and migration by regulating cholesterol metabolism via activation of the mTOR signaling pathway in a LIN28B-interacting manner. These findings provide new insight into the role of LINC01605 in PDAC tumor growth and liver metastasis as well as its value for clinical approaches as a metabolic therapeutic target in PDAC.

Decoding heterogeneous and coordinated tissue architecture in glioblastoma using spatial transcriptomics

Glioblastoma multiforme (GBM) is one of the most lethal brain tumors, characterized by profound heterogeneity. While single-cell transcriptomic studies have revealed extensive intra-tumor heterogeneity, shed light on intra-tumor diversity, spatial intricacies remain largely unexplored. Leveraging clinical GBM specimens, this study employs spatial transcriptomics technology to delve into gene expression heterogeneity. Our investigation unveils a significant enrichment of tissue stem cell signature in regions bordering necrosis and the peritumoral area, positively correlated with the mesenchymal subtype signature. Moreover, upregulated genes in these regions are linked with extracellular matrix (ECM)-receptor interaction, proteoglycans, as well as vascular endothelial growth factor (VEGF) and angiopoietin-Tie (ANGPT) signaling pathways. In contrast, signatures related to glycogen metabolism and oxidative phosphorylation show no relevance to pathological zoning, whereas creatine metabolism signature is notably exclusive to vascular-enriched areas. These spatial profiles not only offer valuable references but also pave the way for future in-depth functional and mechanistic investigations into GBM progression.

Organelle adaptations in response to mechanical forces during tumour dissemination

Cell migration plays a pivotal role in various biological processes including cancer dissemination and successful metastasis, where the role of mechanical signals is increasingly acknowledged. This review focuses on the intricate mechanisms through which cancer cells modulate their migratory strategies via organelle adaptations in response to the extracellular matrix (ECM). Specifically, the nucleus and mitochondria emerge as pivotal mediators in this process. These organelles serve as sensors, translating mechanical stimuli into rapid metabolic alterations that sustain cell migration. Importantly, prolonged exposure to such stimuli can induce transcriptional or epigenetic changes, ultimately enhancing metastatic traits. Deciphering the intricate interplay between ECM properties and organelle adaptations not only advances our understanding of cytoskeletal dynamics but also holds promise for the development of innovative anti-metastatic therapeutic strategies.

Recreating metabolic interactions of the tumour microenvironment

Tumours are heterogeneous tissues containing diverse populations of cells and an abundant extracellular matrix (ECM). This tumour microenvironment prompts cancer cells to adapt their metabolism to survive and grow. Besides epigenetic factors, the metabolism of cancer cells is shaped by crosstalk with stromal cells and extracellular components. To date, most experimental models neglect the complexity of the tumour microenvironment and its relevance in regulating the dynamics of the metabolism in cancer. We discuss emerging strategies to model cellular and extracellular aspects of cancer metabolism. We highlight cancer models based on bioengineering, animal, and mathematical approaches to recreate cell-cell and cell-matrix interactions and patient-specific metabolism. Combining these approaches will improve our understanding of cancer metabolism and support the development of metabolism-targeting therapies.

Mechanical regulation of mitochondrial morphodynamics in cancer cells by extracellular microenvironment

Recently, it has been recognized that physical abnormalities (e.g. elevated solid stress, elevated interstitial fluid pressure, increased stiffness) are associated with tumor progression and development. Additionally, these mechanical forces originating from tumor cell environment through mechanotransduction pathways can affect metabolism. On the other hand, mitochondria are well-known as bioenergetic, biosynthetic, and signaling organelles crucial for sensing stress and facilitating cellular adaptation to the environment and physical stimuli. Disruptions in mitochondrial dynamics and function have been found to play a role in the initiation and advancement of cancer. Consequently, it is logical to hypothesize that mitochondria dynamics subjected to physical cues may play a pivotal role in mediating tumorigenesis. Recently mitochondrial biogenesis and turnover, fission and fusion dynamics was linked to mechanotransduction in cancer. However, how cancer cell mechanics and mitochondria functions are connected, still remain poorly understood. Here, we discuss recent studies that link mechanical stimuli exerted by the tumor cell environment and mitochondria dynamics and functions. This interplay between mechanics and mitochondria functions may shed light on how mitochondria regulate tumorigenesis.

Unraveling ETC complex I function in ferroptosis reveals a potential ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers

The role of the mitochondrial electron transport chain (ETC) in regulating ferroptosis is not fully elucidated. Here, we reveal that pharmacological inhibition of the ETC complex I reduces ubiquinol levels while decreasing ATP levels and activating AMP-activated protein kinase (AMPK), the two effects known for their roles in promoting and suppressing ferroptosis, respectively. Consequently, the impact of complex I inhibitors on ferroptosis induced by glutathione peroxidase 4 (GPX4) inhibition is limited. The pharmacological inhibition of complex I in LKB1-AMPK-inactivated cells, or genetic ablation of complex I (which does not trigger apparent AMPK activation), abrogates the AMPK-mediated ferroptosis-suppressive effect and sensitizes cancer cells to GPX4-inactivation-induced ferroptosis. Furthermore, complex I inhibition synergizes with radiotherapy (RT) to selectively suppress the growth of LKB1-deficient tumors by inducing ferroptosis in mouse models. Our data demonstrate a multifaceted role of complex I in regulating ferroptosis and propose a ferroptosis-inducing therapeutic strategy for LKB1-deficient cancers.

CYRI-B-mediated macropinocytosis drives metastasis via lysophosphatidic acid receptor uptake

Pancreatic ductal adenocarcinoma carries a dismal prognosis, with high rates of metastasis and few treatment options. Hyperactivation of KRAS in almost all tumours drives RAC1 activation, conferring enhanced migratory and proliferative capacity as well as macropinocytosis. Macropinocytosis is well understood as a nutrient scavenging mechanism, but little is known about its functions in trafficking of signalling receptors. We find that CYRI-B is highly expressed in pancreatic tumours in a mouse model of KRAS and p53-driven pancreatic cancer. Deletion of Cyrib (the gene encoding CYRI-B protein) accelerates tumourigenesis, leading to enhanced ERK and JNK-induced proliferation in precancerous lesions, indicating a potential role as a buffer of RAC1 hyperactivation in early stages. However, as disease progresses, loss of CYRI-B inhibits metastasis. CYRI-B depleted tumour cells show reduced chemotactic responses to lysophosphatidic acid, a major driver of tumour spread, due to impaired macropinocytic uptake of the lysophosphatidic acid receptor 1. Overall, we implicate CYRI-B as a mediator of growth and signalling in pancreatic cancer, providing new insights into pathways controlling metastasis.

Extracellular matrix stiffness as an energy metabolism regulator drives osteogenic differentiation in mesenchymal stem cells

The biophysical factors of biomaterials such as their stiffness regulate stem cell differentiation. Energy metabolism has been revealed an essential role in stem cell lineage commitment. However, whether and how extracellular matrix (ECM) stiffness regulates energy metabolism to determine stem cell differentiation is less known. Here, the study reveals that stiff ECM promotes glycolysis, oxidative phosphorylation, and enhances antioxidant defense system during osteogenic differentiation in MSCs. Stiff ECM increases mitochondrial fusion by enhancing mitofusin 1 and 2 expression and inhibiting the dynamin-related protein 1 activity, which contributes to osteogenesis. Yes-associated protein (YAP) impacts glycolysis, glutamine metabolism, mitochondrial dynamics, and mitochondrial biosynthesis to regulate stiffness-mediated osteogenic differentiation. Furthermore, glycolysis in turn regulates YAP activity through the cytoskeletal tension-mediated deformation of nuclei. Overall, our findings suggest that YAP is an important mechanotransducer to integrate ECM mechanical cues and energy metabolic signaling to affect the fate of MSCs. This offers valuable guidance to improve the scaffold design for bone tissue engineering constructs.

Context-dependent roles for ubiquitous mitochondrial creatine kinase CKMT1 in breast cancer progression

Metabolic reprogramming is a hallmark of cancer, enabling cancer cells to rapidly proliferate, invade, and metastasize. We show that creatine levels in metastatic breast cancer cell lines and secondary metastatic tumors are driven by the ubiquitous mitochondrial creatine kinase (CKMT1). We discover that, while CKMT1 is highly expressed in primary tumors and promotes cell viability, it is downregulated in metastasis. We further show that CKMT1 downregulation, as seen in breast cancer metastasis, drives up mitochondrial reactive oxygen species (ROS) levels. CKMT1 downregulation contributes to the migratory and invasive potential of cells by ROS-induced upregulation of adhesion and degradative factors, which can be reversed by antioxidant treatment. Our study thus reconciles conflicting evidence about the roles of metabolites in the creatine metabolic pathway in breast cancer progression and reveals that tight, context-dependent regulation of CKMT1 expression facilitates cell viability, cell migration, and cell invasion, which are hallmarks of metastatic spread.

Quantitative Metabolomics and Lipoprotein Analysis of PDAC Patients Suggests Serum Marker Categories for Pancreatic Function, Pancreatectomy, Cancer Metabolism, and Systemic Disturbances

Pancreatic ductal adenocarcinoma (PDAC) is difficult to diagnose in the early stages and lacks reliable biomarkers. The scope of this project was to establish quantitative nuclear magnetic resonance (NMR) spectroscopy to comprehensively study blood serum alterations in PDAC patients. Serum samples from 34 PDAC patients obtained before and after pancreatectomy as well as 83 age- and sex-matched control samples from healthy donors were analyzed with in vitro diagnostics research (IVDr) proton NMR spectroscopy at 600 MHz. Uni- and multivariate statistics were applied to identify significant biofluid alterations. We identified 29 significantly changed metabolites and 98 lipoproteins when comparing serum from healthy controls with those of PDAC patients. The most prominent features were assigned to (i) markers of pancreatic function (e.g., glucose and blood triglycerides), (ii) markers related to surgery (e.g., ketone bodies and blood cholesterols), (iii) PDAC-associated markers (e.g., amino acids and creatine), and (iv) markers for systemic disturbances in PDAC (e.g., gut metabolites DMG, TMAO, DMSO2, and liver lipoproteins). Quantitative serum NMR spectroscopy is suited as a diagnostic tool to investigate PDAC. Remarkably, 2-hydroxybutyrate (2-HB) as a previously suggested marker for insulin resistance was found in extraordinarily high levels only after pancreatectomy, suggesting this metabolite is the strongest marker for pancreatic loss of function.

DNA nanomachines reveal an adaptive energy mode in confinement-induced amoeboid migration powered by polarized mitochondrial distribution

Energy metabolism is highly interdependent with adaptive cell migration in vivo. Mechanical confinement is a critical physical cue that induces switchable migration modes of the mesenchymal-to-amoeboid transition (MAT). However, the energy states in distinct migration modes, especially amoeboid-like stable bleb (A2) movement, remain unclear. In this report, we developed multivalent DNA framework-based nanomachines to explore strategical mitochondrial trafficking and differential ATP levels during cell migration in mechanically heterogeneous microenvironments. Through single-particle tracking and metabolomic analysis, we revealed that fast A2-moving cells driven by biomimetic confinement recruited back-end positioning of mitochondria for powering highly polarized cytoskeletal networks, preferentially adopting an energy-saving mode compared with a mesenchymal mode of cell migration. We present a versatile DNA nanotool for cellular energy exploration and highlight that adaptive energy strategies coordinately support switchable migration modes for facilitating efficient metastatic escape, offering a unique perspective for therapeutic interventions in cancer metastasis.

Screening Metabolic Biomarkers in KRAS Mutated Mouse Acinar and Human Pancreatic Cancer Cells via Single-Cell Mass Spectrometry

Pancreatic cancer is a highly aggressive and rapidly progressing disease, often diagnosed in advanced stages due to the absence of early noticeable symptoms. The KRAS mutation is a hallmark of pancreatic cancer, yet the underlying mechanisms driving pancreatic carcinogenesis remain elusive. Cancer cells display significant metabolic heterogeneity, which is relevant to the pathogenesis of cancer. Population measurements may obscure information about the metabolic heterogeneity among cancer cells. Therefore, it is crucial to analyze metabolites at the single-cell level to gain a more comprehensive understanding of metabolic heterogeneity. In this study, we employed a 3D-printed ionization source for metabolite analysis in both mice and human pancreatic cancer cells at the single-cell level. Using advanced machine learning algorithms and mass spectral feature selection, we successfully identified 23 distinct metabolites that are statistically significantly different in KRAS mutant human pancreatic cancer cells and mouse acinar cells bearing the oncogenic KRAS mutation. These metabolites encompass a variety of chemical classes, including organic nitrogen compounds, organic acids and derivatives, organoheterocyclic compounds, benzenoids, and lipids. These findings shed light on the metabolic remodeling associated with KRAS-driven pancreatic cancer initiation and indicate that the identified metabolites hold promise as potential diagnostic markers for early detection in pancreatic cancer patients.

The C. elegans anchor cell: A model to elucidate mechanisms underlying invasion through basement membrane

Cell invasion through basement membrane barriers is crucial during many developmental processes and in immune surveillance. Dysregulation of invasion also drives the pathology of numerous human diseases, such as metastasis and inflammatory disorders. Cell invasion involves dynamic interactions between the invading cell, basement membrane, and neighboring tissues. Owing to this complexity, cell invasion is challenging to study in vivo, which has hampered the understanding of mechanisms controlling invasion. Caenorhabditis elegans anchor cell invasion is a powerful in vivo model where subcellular imaging of cell-basement membrane interactions can be combined with genetic, genomic, and single-cell molecular perturbation studies. In this review, we outline insights gained by studying anchor cell invasion, which span transcriptional networks, translational regulation, secretory apparatus expansion, dynamic and adaptable protrusions that breach and clear basement membrane, and a complex, localized metabolic network that fuels invasion. Together, investigation of anchor cell invasion is building a comprehensive understanding of the mechanisms that underlie invasion, which we expect will ultimately facilitate better therapeutic strategies to control cell invasive activity in human disease.

To squeeze or not: Regulation of cell size by mechanical forces in development and human diseases

Physical constraints, such as compression, shear stress, stretching and tension play major roles during development and tissue homeostasis. Mechanics directly impact physiology, and their alteration is also recognized as having an active role in driving human diseases. Recently, growing evidence has accumulated on how mechanical forces are translated into a wide panel of biological responses, including metabolism and changes in cell morphology. The aim of this review is to summarize and discuss our knowledge on the impact of mechanical forces on cell size regulation. Other biological consequences of mechanical forces will not be covered by this review. Moreover, wherever possible, we also discuss mechanosensors and molecular and cellular signaling pathways upstream of cell size regulation. We finally highlight the relevance of mechanical forces acting on cell size in physiology and human diseases.

TAMC-derived creatine sustains glioblastoma growth

Tumor-associated myeloid cells (TAMCs) are the predominant immune population in glioblastoma (GBM), but the definite role of TAMCs in GBM tumorigenicity remains uncertain. In this issue of Cell Metabolism, Rashidi et al. identify a specific population of TAMCs surrounding hypoxic regions of GBM. These TAMCs provide creatine to nearby tumor cells to promote GBM progression.

Suppression of the KRAS-NRF2 axis shifts arginine into the phosphocreatine energy system in pancreatic cancer cells

In pancreatic ductal adenocarcinomas (PDAC), the KRASG12D-NRF2 axis controls cellular functions such as redox homeostasis and metabolism. Disruption of this axis through suppression of NRF2 leads to profound reprogramming of metabolism. Unbiased transcriptome and metabolome analyses showed that PDAC cells with disrupted KRASG12D-NRF2 signaling (NRF2-/- cells) shift from aerobic glycolysis to metabolic pathways fed by amino acids. Metabolome, RNA-seq and qRT-PCR analyses revealed a blockade of the urea cycle, making NRF2-/- cells dependent on exogenous arginine for survival. Arginine is channeled into anabolic pathways, including the synthesis of phosphocreatine, which generates an energy buffer essential for cell growth. A similar switch was observed in tumor clones that had survived FOLFIRINOX therapy or blockade of KRAS signaling. Inhibition of the creatine pathway with cyclocreatine reduced both ATP and invasion rate in 3D spheroids from NRF2-deficient PDAC cells. Our study provides basis for the rational development of combination therapies for pancreatic cancer.

The AMPK-Sirtuin 1-YAP axis is regulated by fluid flow intensity and controls autophagy flux in kidney epithelial cells

Shear stress generated by urinary fluid flow is an important regulator of renal function. Its dysregulation is observed in various chronic and acute kidney diseases. Previously, we demonstrated that primary cilium-dependent autophagy allows kidney epithelial cells to adapt their metabolism in response to fluid flow. Here, we show that nuclear YAP/TAZ negatively regulates autophagy flux in kidney epithelial cells subjected to fluid flow. This crosstalk is supported by a primary cilium-dependent activation of AMPK and SIRT1, independently of the Hippo pathway. We confirm the relevance of the YAP/TAZ-autophagy molecular dialog in vivo using a zebrafish model of kidney development and a unilateral ureteral obstruction mouse model. In addition, an in vitro assay simulating pathological accelerated flow observed at early stages of chronic kidney disease (CKD) activates YAP, leading to a primary cilium-dependent inhibition of autophagic flux. We confirm this YAP/autophagy relationship in renal biopsies from patients suffering from diabetic kidney disease (DKD), the leading cause of CKD. Our findings demonstrate the importance of YAP/TAZ and autophagy in the translation of fluid flow into cellular and physiological responses. Dysregulation of this pathway is associated with the early onset of CKD.

Mechanobiology of organelles: illuminating their roles in mechanosensing and mechanotransduction

Mechanobiology studies the mechanisms by which cells sense and respond to physical forces, and the role of these forces in shaping cells and tissues themselves. Mechanosensing can occur at the plasma membrane, which is directly exposed to external forces, but also in the cell's interior, for example, through deformation of the nucleus. Less is known on how the function and morphology of organelles are influenced by alterations in their own mechanical properties, or by external forces. Here, we discuss recent advances on the mechanosensing and mechanotransduction of organelles, including the endoplasmic reticulum (ER), the Golgi apparatus, the endo-lysosmal system, and the mitochondria. We highlight open questions that need to be addressed to gain a broader understanding of the role of organelle mechanobiology.

Phenotypic profiling of solute carriers characterizes serine transport in cancer

Serine is a vital amino acid in tumorigenesis. While cells can perform de novo serine synthesis, most transformed cells rely on serine uptake to meet their increased biosynthetic requirements. Solute carriers (SLCs), a family of transmembrane nutrient transport proteins, are the gatekeepers of amino acid acquisition and exchange in mammalian cells and are emerging as anticancer therapeutic targets; however, the SLCs that mediate serine transport in cancer cells remain unknown. Here we perform an arrayed RNAi screen of SLC-encoding genes while monitoring amino acid consumption and cell proliferation in colorectal cancer cells using metabolomics and high-throughput imaging. We identify SLC6A14 and SLC25A15 as major cytoplasmic and mitochondrial serine transporters, respectively. We also observe that SLC12A4 facilitates serine uptake. Dual targeting of SLC6A14 and either SLC25A15 or SLC12A4 diminishes serine uptake and growth of colorectal cancer cells in vitro and in vivo, particularly in cells with compromised de novo serine biosynthesis. Our results provide insight into the mechanisms that contribute to serine uptake and intracellular handling.

Acid-base homeostasis orchestrated by NHE1 defines the pancreatic stellate cell phenotype in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) progresses in an organ with a unique pH landscape, where the stroma acidifies after each meal. We hypothesized that disrupting this pH landscape during PDAC progression triggers pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) to induce PDAC fibrosis. We revealed that alkaline environmental pH was sufficient to induce PSC differentiation to a myofibroblastic phenotype. We then mechanistically dissected this finding, focusing on the involvement of the Na+/H+ exchanger NHE1. Perturbing cellular pH homeostasis by inhibiting NHE1 with cariporide partially altered the myofibroblastic PSC phenotype. To show the relevance of this finding in vivo, we targeted NHE1 in murine PDAC (KPfC). Indeed, tumor fibrosis decreased when mice received the NHE1-inhibitor cariporide in addition to gemcitabine treatment. Moreover, the tumor immune infiltrate shifted from granulocyte rich to more lymphocytic. Taken together, our study provides mechanistic evidence on how the pancreatic pH landscape shapes pancreatic cancer through tuning PSC differentiation.

Dynamic links between mechanical forces and metabolism shape the tumor milieu

Cell function relies on the spatiotemporal dynamics of metabolic reactions. In all physiopathological processes of tissues, mechanical forces impact the structure and function of membranes, enzymes, organelles and regulators of metabolic gene programs, thus regulating cell metabolism. In turn, metabolic pathways feedback impacts the physical properties of cell and tissues. Hence, metabolism and tissue mechanics are dynamically intertwined and continuously interact. Cancer is akin to an ecosystem, comprising tumor cells and various subpopulations of stromal cells embedded in an altered extracellular matrix. The progression of cancer, from initiation to advanced stage and metastasis, is driven by genetic mutations and crucially influenced by physical and metabolic alterations in the tumor microenvironment. These alterations also play a pivotal role in cancer cells evasion from immune surveillance and in developing resistance to treatments. Here, we highlight emerging evidence showing that mechano-metabolic circuits in cancer and stromal cells regulate multiple processes crucial for tumor progression and discuss potential approaches to improve therapeutic treatments by interfering with these circuits.

Mitochondria: At the crossroads between mechanobiology and cell metabolism

Metabolism and mechanics are two key facets of structural and functional processes in cells, such as growth, proliferation, homeostasis and regeneration. Their reciprocal regulation has been increasingly acknowledged in recent years: external physical and mechanical cues entail metabolic changes, which in return regulate cell mechanosensing and mechanotransduction. Since mitochondria are pivotal regulators of metabolism, we review here the reciprocal links between mitochondrial morphodynamics, mechanics and metabolism. Mitochondria are highly dynamic organelles which sense and integrate mechanical, physical and metabolic cues to adapt their morphology, the organization of their network and their metabolic functions. While some of the links between mitochondrial morphodynamics, mechanics and metabolism are already well established, others are still poorly documented and open new fields of research. First, cell metabolism is known to correlate with mitochondrial morphodynamics. For instance, mitochondrial fission, fusion and cristae remodeling allow the cell to fine-tune its energy production through the contribution of mitochondrial oxidative phosphorylation and cytosolic glycolysis. Second, mechanical cues and alterations in mitochondrial mechanical properties reshape and reorganize the mitochondrial network. Mitochondrial membrane tension emerges as a decisive physical property which regulates mitochondrial morphodynamics. However, the converse link hypothesizing a contribution of morphodynamics to mitochondria mechanics and/or mechanosensitivity has not yet been demonstrated. Third, we highlight that mitochondrial mechanics and metabolism are reciprocally regulated, although little is known about the mechanical adaptation of mitochondria in response to metabolic cues. Deciphering the links between mitochondrial morphodynamics, mechanics and metabolism still presents significant technical and conceptual challenges but is crucial both for a better understanding of mechanobiology and for potential novel therapeutic approaches in diseases such as cancer.

Cell-matrix and cell-cell interaction mechanics in guiding migration

Physical properties of tissue are increasingly recognised as major regulatory cues affecting cell behaviours, particularly cell migration. While these properties of the extracellular matrix have been extensively discussed, the contribution from the cellular components that make up the tissue are still poorly appreciated. In this mini-review, we will discuss two major physical components: stiffness and topology with a stronger focus on cell-cell interactions and how these can impact cell migration.

Impact of Opioids on Cellular Metabolism: Implications for Metabolic Pathways Involved in Cancer

Opioid utilization for pain management is prevalent among cancer patients. There is significant evidence describing the many effects of opioids on cancer development. Despite the pivotal role of metabolic reprogramming in facilitating cancer growth and metastasis, the specific impact of opioids on crucial oncogenic metabolic pathways remains inadequately investigated. This review provides an understanding of the current research on opioid-mediated changes to cellular metabolic pathways crucial for oncogenesis, including glycolysis, the tricarboxylic acid cycle, glutaminolysis, and oxidative phosphorylation (OXPHOS). The existing literature suggests that opioids affect energy production pathways via increasing intracellular glucose levels, increasing the production of lactic acid, and reducing ATP levels through impediment of OXPHOS. Opioids modulate pathways involved in redox balance which may allow cancer cells to overcome ROS-mediated apoptotic signaling. The majority of studies have been conducted in healthy tissue with a predominant focus on neuronal cells. To comprehensively understand the impact of opioids on metabolic pathways critical to cancer progression, research must extend beyond healthy tissue and encompass patient-derived cancer tissue, allowing for a better understanding in the context of the metabolic reprogramming already undergone by cancer cells. The current literature is limited by a lack of direct experimentation exploring opioid-induced changes to cancer metabolism as they relate to tumor growth and patient outcome.

The microenvironment dictates glycocalyx construction and immune surveillance

Efforts to identify anti-cancer therapeutics and understand tumor-immune interactions are built with in vitro models that do not match the microenvironmental characteristics of human tissues. Using in vitro models which mimic the physical properties of healthy or cancerous tissues and a physiologically relevant culture medium, we demonstrate that the chemical and physical properties of the microenvironment regulate the composition and topology of the glycocalyx. Remarkably, we find that cancer and age-related changes in the physical properties of the microenvironment are sufficient to adjust immune surveillance via the topology of the glycocalyx, a previously unknown phenomenon observable only with a physiologically relevant culture medium.

Mechano-dependent sorbitol accumulation supports biomolecular condensate

Biomolecular condensates regulate a wide range of cellular functions from signaling to RNA metabolism 1, 2 , yet, the physiologic conditions regulating their formation remain largely unexplored. Biomolecular condensate assembly is tightly regulated by the intracellular environment. Changes in the chemical or physical conditions inside cells can stimulate or inhibit condensate formation 3-5 . However, whether and how the external environment of cells can also regulate biomolecular condensation remain poorly understood. Increasing our understanding of these mechanisms is paramount as failure to control condensate formation and dynamics can lead to many diseases 6, 7 . Here, we provide evidence that matrix stiffening promotes biomolecular condensation in vivo . We demonstrate that the extracellular matrix links mechanical cues with the control of glucose metabolism to sorbitol. In turn, sorbitol acts as a natural crowding agent to promote biomolecular condensation. Using in silico simulations and in vitro assays, we establish that variations in the physiological range of sorbitol, but not glucose, concentrations, are sufficient to regulate biomolecular condensates. Accordingly, pharmacologic and genetic manipulation of intracellular sorbitol concentration modulates biomolecular condensates in breast cancer - a mechano-dependent disease. We propose that sorbitol is a mechanosensitive metabolite enabling protein condensation to control mechano-regulated cellular functions. Altogether, we uncover molecular driving forces underlying protein phase transition and provide critical insights to understand the biological function and dysfunction of protein phase separation.

Depletion of creatine phosphagen energetics with a covalent creatine kinase inhibitor

Creatine kinases (CKs) provide local ATP production in periods of elevated energetic demand, such as during rapid anabolism and growth. Thus, creatine energetics has emerged as a major metabolic liability in many rapidly proliferating cancers. Whether CKs can be targeted therapeutically is unknown because no potent or selective CK inhibitors have been developed. Here we leverage an active site cysteine present in all CK isoforms to develop a selective covalent inhibitor of creatine phosphagen energetics, CKi. Using deep chemoproteomics, we discover that CKi selectively engages the active site cysteine of CKs in cells. A co-crystal structure of CKi with creatine kinase B indicates active site inhibition that prevents bidirectional phosphotransfer. In cells, CKi and its analogs rapidly and selectively deplete creatine phosphate, and drive toxicity selectively in CK-dependent acute myeloid leukemia. Finally, we use CKi to uncover an essential role for CKs in the regulation of proinflammatory cytokine production in macrophages.

Epigenetic reprogramming-induced guanidinoacetic acid synthesis promotes pancreatic cancer metastasis and transcription-activating histone modifications

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) tends to undergo distant metastasis, especially liver metastasis, leading to a poor prognosis. Metabolic remodelling and epigenetic reprogramming are two important hallmarks of malignant tumours and participate in regulating PDAC tumorigenesis and metastasis. However, the interaction between these two processes during PDAC metastasis has not been fully elucidated.

METHODS

We performed metabolomics analysis to identify the critical metabolites associated with PDAC liver metastasis and focused on guanidinoacetic acid (GAA). Intracellular GAA content was significantly increased in liver metastatic PDAC cells compared to primary cancer cells in mouse xenograft tumour models. The effects of GAA supplementation and glycine amidinotransferase (GATM) knockdown on PDAC metastasis were assessed by analysing cell migration, filopodia formation, epithelial-mesenchymal transition (EMT), and in vivo metastasis in different cell and animal models. Next, ChIP‒qPCR, 3C‒qPCR, and CRISPRi/dCas9-KRAB experiments were used to validate the "epigenome-metabolome" mechanism. Finally, the results of in vitro approaches, including RNA-seq, CUT&RUN, RT‒qPCR, and western blot analyses, as well as luciferase reporter gene assay and transwell assay, revealed the GAA-c-Myc-HMGA axis and transcription-activating histone modifications reprogramming.

RESULTS

A high level of intracellular GAA was associated with PDAC liver metastasis. GAA could promote the migration, EMT, and liver metastasis of pancreatic cancer cells in vitro and in vivo. Next, we explored the role of GATM-mediated de novo GAA synthesis in pancreatic cancer metastasis. High expression of GATM was positively correlated with advanced N stage in PDAC. Knockdown of GATM significantly reduced the intracellular level of GAA, suppressed EMT, and inhibited PDAC liver metastasis, and these effects were attenuated by GAA supplementation. Mechanistically, we identified the active enhancers looped to the Gatm gene locus that promoted GATM expression and PDAC liver metastasis. Furthermore, we found that GAA promoted cell migration and EMT by regulating c-Myc-mediated high mobility group AT-hook protein expression. Moreover, GAA increased the H3K4me3 modification level by upregulating histone methyltransferases, which induced the transcription of metastasis-related genes, including Myc.

CONCLUSIONS

These findings revealed the critical role of the epigenome-metabolome interaction in regulating PDAC liver metastasis and suggested potential therapeutic strategies targeting GAA metabolism and epigenetic regulatory mechanisms.

Reprogramming of tissue metabolism during cancer metastasis

Cancer is a systemic disease that involves malignant cell-intrinsic and -extrinsic metabolic adaptations. Most studies have tended to focus on elucidating the metabolic vulnerabilities in the primary tumor microenvironment, leaving the metastatic microenvironment less explored. In this opinion article, we discuss the current understanding of the metabolic crosstalk between the cancer cells and the tumor microenvironment, both at local and systemic levels. We explore the possible influence of the primary tumor secretome to metabolically and epigenetically rewire the nonmalignant distant organs during prometastatic niche formation and successful metastatic colonization by the cancer cells. In an attempt to understand the process of prometastatic niche formation, we have speculated how cancer may hijack the inherent regenerative propensity of tissue parenchyma during metastatic colonization.

AMPK is a mechano-metabolic sensor linking cell adhesion and mitochondrial dynamics to Myosin-dependent cell migration

Cell migration is crucial for cancer dissemination. We find that AMP-activated protein kinase (AMPK) controls cell migration by acting as an adhesion sensing molecular hub. In 3-dimensional matrices, fast-migrating amoeboid cancer cells exert low adhesion/low traction linked to low ATP/AMP, leading to AMPK activation. In turn, AMPK plays a dual role controlling mitochondrial dynamics and cytoskeletal remodelling. High AMPK activity in low adhering migratory cells, induces mitochondrial fission, resulting in lower oxidative phosphorylation and lower mitochondrial ATP. Concurrently, AMPK inactivates Myosin Phosphatase, increasing Myosin II-dependent amoeboid migration. Reducing adhesion or mitochondrial fusion or activating AMPK induces efficient rounded-amoeboid migration. AMPK inhibition suppresses metastatic potential of amoeboid cancer cells in vivo, while a mitochondrial/AMPK-driven switch is observed in regions of human tumours where amoeboid cells are disseminating. We unveil how mitochondrial dynamics control cell migration and suggest that AMPK is a mechano-metabolic sensor linking energetics and the cytoskeleton.

Creatine kinase brain-type regulates BCAR1 phosphorylation to facilitate DNA damage repair

Creatine kinase (CK) is an essential metabolic enzyme mediating creatine/phosphocreatine interconversion and shuttle to replenish ATP for energy needs. Ablation of CK causes a deficiency in energy supply that eventually results in reduced muscle burst activity and neurological disorders in mice. Besides the well-established role of CK in energy-buffering, the mechanism underlying the non-metabolic function of CK is poorly understood. Here we demonstrate that creatine kinase brain-type (CKB) may function as a protein kinase to regulate BCAR1 Y327 phosphorylation that enhances the association between BCAR1 and RBBP4. Then the complex of BCAR1 and RPPB4 binds to the promoter region of DNA damage repair gene RAD51 and activates its transcription by modulating histone H4K16 acetylation to ultimately promote DNA damage repair. These findings reveal the possible role of CKB independently of its metabolic function and depict the potential pathway of CKB-BCAR1-RBBP4 operating in DNA damage repair.