Targeted inhibition of branched-chain amino acid metabolism drives apoptosis of glioblastoma by facilitating ubiquitin degradation of Mfn2 and oxidative stress

Unveiling the Maze: Branched-Chain Amino Acids Fueling the Dynamics of Cancer Metabolism and Progression

Branched-chain amino acids (BCAAs) are essential for protein synthesis and play a crucial role in activating signaling pathways that regulate cell growth and division. Growing evidence reveals their complex role in cancer, particularly in how they support the metabolic reprogramming of tumor cells. BCAAs contribute to an environment that promotes tumor growth and survival by affecting energy balance and key cellular signaling networks. This review highlights recent advances in understanding how BCAAs influence cancer metabolism, emphasizing their dual function as both essential nutrients and sources of metabolic fuel. It also explores how BCAAs interact with other metabolic pathways, revealing potential targets for therapy. By uncovering these cancer-specific dependencies on BCAAs, this work points to promising strategies for disrupting tumor progression and developing new treatment approaches.

BCAA metabolism in cancer progression and therapy resistance: The balance between fuel and cell signaling

Branched-chain amino acids (BCAAs), including leucine, isoleucine, and valine, play a crucial role in cellular metabolism and signaling. Recent studies have demonstrated that BCAA metabolic reprogramming is a key driver of tumor progression and treatment resistance in various cancers. BCAA metabolism supports cancer cell growth, survival, and proliferation by modulating pathways such as mTOR signaling and oxidative stress responses. By promoting immunosuppressive conditions and increasing the survival rate of cancer stem cells (CSCs), BCAAs contribute to immune evasion and resistance to therapies such as chemotherapy and immune checkpoint inhibitors. This article explores the different metabolic reprogramming patterns of BCAAs in various tumors and introduces BCAA-related metabolic targets for overcoming tumor resistance, offering new directions for precision cancer treatment, reducing resistance, and improving patient outcomes.

Mitochondrial enzyme HIBADH protects against calcium oxalate nephrolithiasis by modulating oxidative stress and apoptosis

Calcium oxalate (CaOx) nephrolithiasis, as one of the most common types of kidney stones, poses a major threat to human health. This study aimed to investigate the role of 3-hydroxyisobutyrate dehydrogenase (HIBADH) in the pathogenesis of CaOx nephrolithiasis. CaOx nephrolithiasis models were established in rats via 1 % ethylene glycol and 2 % ammonium chloride induction and in HK-2 cells using calcium oxalate monohydrate (COM, 100 μg/mL). HIBADH expression was modulated through plasmid transfection and siRNA knockdown in vitro, and AAV2/9-mediated gene transfer in vivo. Multiple parameters were assessed, including cell crystal adhesion, apoptosis, cell cycle distribution, oxidative stress markers (SOD, MDA, MitoSOX fluorescence), and mitochondrial function (ATP level, mitochondrial membrane potential), using various techniques such as crystal adhesion assay, flow cytometry, western blot, qRT-PCR, and fluorescence microscopy. Kidney tissues were analyzed through H&E, Von Kossa, and PAS staining. Results demonstrated that HIBADH expression was significantly downregulated in CaOx nephrolithiasis rats and COM-treated HK-2 cells. In vitro, HIBADH overexpression reduced cell crystal adhesion and apoptosis, promoted cell cycle progression, mitigated mitochondria-involved cellular oxidative stress, and enhanced mitochondrial function in COM-induced HK-2 cells. In vivo, AAV2/9-mediated HIBADH overexpression attenuated crystal deposits and tubular injury, reduced apoptosis, and mitigated mitochondria-involved cellular oxidative stress in kidney tissues. The mitochondria-targeted antioxidant Mito-TEMPO counteracted the effects of HIBADH silencing, highlighting the role of mitochondrial function in HIBADH's protective mechanism. This study identifies HIBADH as a critical regulator in CaOx nephrolithiasis, exerting its protective effects through modulation of mitochondrial function and mitochondria-involved cellular oxidative stress, cell crystal adhesion, and apoptosis. Our findings elucidate the link between mitochondrial metabolism and kidney stone formation, positioning HIBADH as a key protective factor and a promising candidate with therapeutic potential for CaOx nephrolithiasis.

Research advances in branched-chain amino acid metabolism in tumors

The metabolic reprogramming of amino acids is an important component of tumor metabolism. Branched-chain amino acids (BCAAs) perform important functions in tumor progression. They are the important amino donor and are involved in the synthesis of various non-essential amino acids, nucleotides, and polyamines to satisfy the increased demand for nitrogen sources. This review summarizes the studies related to abnormalities in BCAA metabolism during tumorigenesis and the potential therapeutic targets. The expression of BCAA transporters was significantly upregulated in tumor cells, which increases BCAA uptake. High expression of the BCAA transaminases is prevalent in various tumors, however, the dehydrogenation step of BCAA catabolism is inhibited in tumors. This review shows that BCAA metabolic reprogramming is an important tumor metabolic feature, and metabolic genes of BCAAs play a crucial role in tumor metabolism, representing a good auxiliary target for early clinical diagnosis and treatment. In addition, BCAAs are indispensable for maintaining immune system function, and dietary supplementation with BCAAs can enhance the activity of immune cells. Therefore, BCAA supplementation in tumor patients may affect the interaction between the immune system and tumors.

Role of ubiquitination-driven metabolisms in oncogenesis and cancer therapy

Ubiquitination represents one of the most critical post-translational modifications, comprising a multi-stage enzyme process that plays a pivotal role in a myriad of cellular biological activities. The deregulation of the processes of ubiquitination and deubiquitination is associated with the development of cancers and other diseases. This typescript reviews the impact of ubiquitination on metabolic processes, elucidating the regulatory functions of ubiquitination on pivotal enzymes within metabolic pathways in pathological contexts. It underscores the role of ubiquitination-driven metabolism disorders in the etiology of cancers, and oncogenesis, and highlights the potential therapeutic efficacy of targeting ubiquitination-driven enzymes in cancer metabolism, their combination with immune checkpoint inhibitors, and their clinical applications.

The combined antimicrobial activity of α-lactalbumin and thymol against Escherichia coli and Staphylococcus aureus

Thymol showed good antimicrobial activity, however, the poor aqueous solubility limits it to apply in food industry. α-Lactalbumin can be used to delivery hydrophobic molecules, then enhancing their biological activities. The study investigates the potential of α-lactalbumin to expand the application range of thymol, further to evaluate the antimicrobial activity of the α-lactalbumin-thymol complexation. Multi-spectroscopy techniques and computational simulations have confirmed the successful complexation, driving mainly by van der Waals force. The α-lactalbumin-thymol complexation exhibited the superior antimicrobial activity than thymol against Escherichia coli and Staphylococcus aureus, as indicated by lower or comparable minimum inhibitory concentration (336 μg/mL and 224 μg/mL, respectively), fewer colony forming units, and larger inhibition zone diameters. Furthermore, α-lactalbumin enhanced the degree of membrane damage by thymol. The complexation preserved no obvious cytotoxicity against HeLa cells. This study indicates that the α-lactalbumin-thymol complexation chelates hold promise as natural antimicrobial agents in the food processing industry.

Maternal-offspring brain and tissue cross-talk in preeclampsia: insights from a rat model

This study aimed to investigate the differential metabolic profiles across maternal and offspring brains, serum, and placental tissues in preeclampsia (PE), with a particular focus on elucidating the maternal-offspring brain and tissue cross-talk that may contribute to the complex pathophysiology of PE. PE was induced in rats using the nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) to simulate both early-onset PE (EOPE) and late-onset PE (LOPE). We utilized non-targeted proton nuclear magnetic resonance (NMR) metabolomics to characterize the metabolic profiles of serum, placental tissue extracts, and brain tissues from both mothers and offspring. Multivariate analysis, Spearman correlation, Density-Based Spatial Clustering of Applications with Noise algorithm, Data-Driven Statistical Predictive Correlation network analysis and Tissue heterogeneity analysis were employed to explore tissue-specific metabolic signatures and their interactions. Following L-NAME induction, both EOPE and LOPE presented significant metabolic differences and shared traits across tissues, with distinct tissue-specific responses characterizing the metabolic profile of PE. Serum from both PE groups showed a decrease in tryptophan, isobutyrate, and lactate, with an increase in betaine. Lactate was upregulated in placental tissues, highlighting its metabolic role. Extensive intra-tissue metabolic correlations and inter-tissue metabolite exchanges were detected among the maternal brain, serum, placenta, and offspring brain across all three experimental groups. EOPE and LOPE exhibited distinctly different metabolic characteristics and trajectories of differential metabolites, along with diverse interaction patterns between the maternal/offspring brain and the placenta. This study uncovers the multi-tissue metabolic remodeling in response to preeclampsia, implying that addressing pathophysiological stress is crucial and may have potential implications for neurological outcomes. The comprehensive analysis highlights the pivotal role of the brain-placenta axis in preeclampsia, advocating for a classified diagnostic and management approach.

Amino acid metabolism in glioblastoma pathogenesis, immune evasion, and treatment resistance

Glioblastoma (GBM) ranks among the most lethal primary tumors of the central nervous system. This is partly due to its complex intracellular metabolism and interactions with the surrounding tumor microenvironment (TME). Compelling evidence represents that altered amino acids (AAs) metabolism plays a crucial role in both areas. The role of AAs and their metabolites in glioma biology is an emerging topic. Therefore, this review was conducted to summarize the current knowledge about the molecular mechanisms by which AAs participate in the GBM pathogenesis. AAs can directly influence tumor progression by affecting tumor cell metabolism or indirectly by releasing bioactive agents through particular metabolic pathways. This review begins by examining the metabolic pathways of essential AAs, such as tryptophan, tyrosine, and phenylalanine, which contribute to synthesizing critical neurotransmitters and shape tumor metabolism signatures. We explore how these pathways impact tumor growth and immune modulation, focusing on how AAs and their metabolites can promote malignant properties in GBM cells. AAs also play a pivotal role in reprogramming the TME, contributing to immune evasion and resistance to therapy. The review further discusses how tumor metabolism signatures, influenced by AA metabolism, can enhance the immunosuppressive microenvironment, providing new avenues for targeted immunotherapies. Finally, we outline potential therapeutic strategies to modulate AA metabolism and emphasize critical opportunities for future research to improve GBM management.

Metabolomic profiling of plasma from glioma and meningioma patients based on two complementary mass spectrometry techniques

INTRODUCTION

Extracranial and intracranial tumors are a diverse group of malignant and benign neoplasms, influenced by multiple factors. Given the complex nature of these tumors and usually late or accidental diagnosis, minimally invasive, rapid, early, and accurate diagnostic methods are urgently required. Metabolomics offers promising insights into central nervous system tumors by uncovering distinctive metabolic changes linked to tumor development.

OBJECTIVES

This study aimed to elucidate the role of altered metabolites and the associated biological pathways implicated in the development of gliomas and meningiomas.

METHODS

The study was conducted on 95 patients with gliomas, 68 patients with meningiomas, and 71 subjects as a control group. The metabolic profiling of gliomas and meningiomas achieved by integrating untargeted metabolomic analysis based on GC-MS and targeted analysis performed using LC-MS/MS represents the first comprehensive study. Three comparisons (gliomas or meningiomas vs. controls as well as gliomas vs. meningiomas) were performed to reveal statistically significant metabolites.

RESULTS

Comparative analysis revealed 97, 56, and 27 significant metabolites for gliomas vs. controls, meningiomas vs. controls and gliomas vs. meningiomas comparison, respectively. Moreover, among above mentioned comparisons unique metabolites involved in arginine biosynthesis and metabolism, the Krebs cycle, and lysine degradation pathways were found. Notably, 2-aminoadipic acid has been identified as a metabolite that can be used in distinguishing two tumor types.

CONCLUSIONS

Our results provide a deeper understanding of the metabolic changes associated with brain tumor development and progression.

CHIP-mediated ubiquitin degradation of BCAT1 regulates glioma cell proliferation and temozolomide sensitivity

Glioma, a malignant and infiltrative neoplasm of the central nervous system, poses a significant threat due to its high mortality rates. Branched-chain amino acid transaminase 1 (BCAT1), a key enzyme in branched-chain amino acid (BCAA) catabolism, exhibits elevated expression in gliomas and correlates strongly with poor prognosis. Nonetheless, the regulatory mechanisms underlying this increased BCAT1 expression remains incompletely understood. In this study, we reveal that ubiquitination at Lys360 facilitates BCAT1 degradation, with low ubiquitination levels contributing to high BCAT1 expression in glioma cells. The Carboxyl terminus of Hsc70-interacting protein (CHIP), an E3 ubiquitin ligase, interacts with BCAT1 via its coiled-coil (CC) domain, promoting its K48-linkage ubiquitin degradation through proteasomal pathway. Moreover, CHIP-mediated BCAT1 degradation induces metabolic reprogramming, and impedes glioma cell proliferation and tumor growth both in vitro and in vivo. Furthermore, a positive correlation is observed between low CHIP expression, elevated BCAT1 levels, and unfavorable prognosis among glioma patients. Additionally, we show that the CHIP/BCAT1 axis enhances glioma sensitivity to temozolomide by reducing glutathione (GSH) synthesis and increasing oxidative stress. These findings underscore the critical role of CHIP/BCAT1 axis in glioma cell proliferation and temozolomide sensitivity, highlighting its potential as a diagnostic marker and therapeutic target in glioma treatment.