Search Results (48)

Conventional chondrosarcoma (CS), the second most common primary bone malignancy, presents a significant therapeutic challenge due to high levels of resistance to chemotherapy and radiotherapy. Current treatment is limited to surgical resection, which is often incomplete due to tumor involvement of critical structures. Recent molecular profiling studies have highlighted frequent Isocitrate Dehydrogenase 1 (IDH1) and Isocitrate Dehydrogenase 2 (IDH2) mutations, along with AXL phosphorylation and AXL-associated pathway activity, as candidate molecular features in CS. However, their functional roles may vary by subtype and require context-specific interpretation. IDH1/2 mutations are thought to contribute to CS tumorigenesis through metabolic and epigenetic mechanisms, including D-2-hydroxyglutarate (D-2-HG) accumulation, altered differentiation programs, and epigenetic dysregulation, although direct mechanistic evidence in CS remains less complete than in other IDH-mutant malignancies. Concurrently, AXL, which has been implicated in epithelial-to-mesenchymal transition (EMT), immune evasion, and therapeutic resistance, is emerging as a candidate signaling node in CS biology. Potential convergence between IDH1/2-associated metabolic or epigenetic states and AXL-associated signaling remains hypothesis-generating and requires CS-specific validation. This review synthesizes current evidence on the roles of IDH1/2 mutations and dysregulation of AXL signaling in CS, emphasizing their potential contributions to tumor aggressiveness, immune suppression, and resistance to therapy. Additionally, we explore current developments in targeted therapy exploiting IDH1/2 and AXL dysregulation. Full article

Background/Objectives: Chondrosarcoma, glioblastoma, acute myeloid leukemia, chronic lymphocytic leukemia, and cholangiocarcinoma cancers all contain mutations in the gene isocitrate dehydrogenase 2 (IDH2). The mutant IDH2 enzyme metabolizes alpha-ketoglutarate (αKG) into the potent oncometabolite D-2-hydroxyglutarate (D2HG) in the mitochondria of these cancers, leading to altered cellular metabolism. Emerging evidence suggests that mitochondrial transfer between cancer and recipient cells represents an important form of intercellular communication that may influence cellular metabolism. The presence of intercellular TNTs between IDH2-mutant chondrosarcoma cells motivated an investigation into mitochondria-associated physiological changes occurring during an intercellular exchange with immune cells. A mitochondrial transfer is a two-way process, and we hypothesized that mitochondria-associated material derived from IDH2-mutant chondrosarcoma cells is exchanged with normal cells through TNTs. We further hypothesized that disruption of the actin cytoskeleton will inhibit this transfer. Accordingly, our objectives were to (1) quantify the extent and directionality of the mitochondrial exchange between IDH2-mutant cells and wild-type cells and to modulate this process via cytoskeletal inhibitors, and (2) measure the metabolic changes associated with the coculture and mitochondrial exchange. Methods: IDH2-mutant chondrosarcoma cells were cocultured with immune cells in vitro to quantify the extent and directionality of the mitochondrial exchange, and cytochalasin B was used as a cytoskeletal inhibitor to disrupt actin-dependent transfer. Metabolic changes associated with coculture and mitochondrial exchange were assessed using Seahorse extracellular flux analysis. Results: The experimental data presented here demonstrate a bidirectional exchange of mitochondria-associated material between IDH2-mutant chondrosarcoma cells and immune cells in vitro, accompanied by metabolic alterations in both cell types. Conclusions: These findings advance our understanding of intercellular communication in the tumor microenvironment and provide a foundation for future studies examining the functional and therapeutic relevance of a mitochondrial exchange in IDH2-mutant cancers. Full article

Isocitrate dehydrogenase 1 (IDH1) mutations are key drivers of glioma biology, influencing tumor aggressiveness and treatment response. To elucidate their molecular impact, we performed proteome analysis on patient-derived (PD) and U87MG glioma cell models with either mutant or wild-type IDH1. We quantified over 6000 protein groups per model, identifying 1594 differentially expressed proteins in PD-AS (IDH1_MUT) vs. PD-GB (IDH1_WT) and 904 in U87_MUT vs. U87_WT. Both IDH1_MUT models exhibited enhanced MHC antigen presentation and interferon signaling, indicative of an altered immune microenvironment. However, metabolic alterations were model-dependent: PD-AS cells shifted toward glycolysis and purine salvage, while U87_MUT cells retained oxidative phosphorylation, potentially due to D2-hydroxyglutarate (2OHG)-mediated HIF1A stabilization. We also observed a predominance of downregulated DNA repair proteins in IDH1_MUT models, particularly those involved in homologous recombination. In contrast, RB1 and ASMTL were strongly upregulated in both IDH1_MUT models, implicating them in DNA repair and cellular stress responses. We also found distinct expression patterns of proteins regulating histone methylation in IDH1_MUT cells, favoring increased methylation of H3K4, H3K9, and H3K36. A key driver of this may be the upregulation of SETD2 in PD-AS, an H3K4 and H3K36 trimethyltransferase linked to the recruitment of HIF1A as well as DNA mismatch repair proteins. This study uncovers candidate biomarkers and pathways relevant to glioma progression and therapeutic targeting, but also underscores the complexity of predicting glioma pathogenesis and treatment responses based on IDH1 mutation status. While proteome profiling provides valuable insights, a comprehensive understanding of IDH1_MUT gliomas will likely require integrative multi-omics approaches, including DNA/RNA methylation profiling, histone and protein post-translational modification analyses, and targeted DNA damage and repair assays. Full article

First-line treatment for localized prostate cancer (PCa) includes radical prostatectomy (RP) for high-risk disease. However, in many cases, patients experience biochemical recurrence (BCR), heralded by rising prostate specific antigen (PSA) levels in the serum. Our goal was to identify metabolic pathways that are disrupted in BCR to determine potential targets of therapy. We conducted metabolomic analysis in prostate tissue from the tumors of 74 patients who underwent prostatectomy as treatment for localized PCa and correlated levels of metabolites with clinical and non-clinical factors. Cholesterol and triglycerides were upregulated in Hispanic vs. non-Hispanic and in obese vs. non-obese individuals, respectively. Both lipids and non-lipids were altered with increasing Gleason grades and clinical stages. High post-RP PSA (>0.1 ng/mL) indicated recurrence (p = 0.0094) and correlated with alterations in 141 metabolites including 114 lipids and 26 non-lipid molecules. The largest increase with high post-RP PSA was in 2-hydroxyglutaric acid (2-HG), a product of the tricarboxylic acid (TCA) cycle, that had previously been established as an oncometabolite in other cancers. 2-HG was highly selective and specific for high post-RP PSA (AUC = 0.8526; p = 0.0002) while Kaplan–Meier curves indicated that among patients who recurred, high 2-HG in the tumor reduced time-to-recurrence from 84 months (for those with low 2-HG) to 38 months (for those with high 2-HG). The addition of D2HG, an enantiomer of 2-HG, increased the growth rate of LNCaP and C4 cells, and also increased Akt and ERK phosphorylation. 2-HG is upregulated in PCa tumors from patients who experience high post-RP PSA indicative of recurrence. Future studies may target this metabolite to prevent recurrent disease. Full article

A periplasmic D-malate:cytochrome c oxidoreductase (DMCO) was identified in Ectopseudomonas oleovorans CECT5344, utilizing 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT) as an artificial electron acceptor. The assay was adapted for a spectrophotometric or native polyacrylamide gel electrophoresis (PAGE) analysis. The DMCO-encoding gene (BN5_4044) was cloned and expressed in Escherichia coli, enabling a partial purification and biochemical characterization. In addition to D-malate, the enzyme oxidizes D-2-hydroxyglutarate and, to a lesser extent, D-lactate, with cytochrome c also serving as an electron acceptor. DMCO requires Zn²⁺ for activity and exists as a dimer, as determined by gel filtration. The in vitro reconstitution of the electron transfer from D-malate to oxygen was achieved using spheroplasts, enriched periplasmic fractions, and cytochrome c. This extracytoplasmic respiration, unique among homologs of this protein, may eliminate the need for a dedicated inner membrane transporter, thereby avoiding potential upstream respiratory bottlenecks. In the context of bioremediation, and particularly regarding the cyanide metabolism, this D-malate oxidation to oxaloacetate facilitates detoxification by forming the corresponding cyanohydrin, which can be subsequently assimilated for growth. Full article

Background/Objectives: Isocitrate dehydrogenase (IDH) mutations are hallmark features in subsets of gliomas, producing the oncometabolite D-2-hydroxyglutarate (2HG). Although IDH mutations are associated with better clinical outcomes, their relationship with tumor progression is complex. This study aimed to investigate, in vitro and in vivo, the phenotypic consequences of IDH mutation and 2HG exposure in glioblastoma (GBM) under normoxic and hypoxic conditions and under temozolomide (TMZ) and radiation exposure. Methods: Experiments were conducted using IDH-wildtype (IDH-wt) and IDH-mutant (IDH-mut) glioma cell lines under controlled oxygen conditions. Functional assays included cell viability, cell cycle analysis, apoptosis profiling, migration, and surface marker expression via flow cytometry. Orthotopic xenografts were established in immunocompromised mice to assess in vivo tumor growth and morphology, followed by MRI and histological analysis. Treatments included TMZ, radiation, and 2HG at varying concentrations. Statistical analyses were performed using SPSS and RStudio. Results:IDH-wt cells exhibited faster proliferation and greater adaptability under hypoxia, while IDH-mut cells showed cell cycle arrest and limited growth. 2HG recapitulated IDH-mut features in IDH-wt cells, including increased apoptosis under TMZ, reduced proliferation, and altered CD24/CD44 expression. In vivo, IDH-wt tumors were larger and more infiltrative, while 2HG administration reduced tumor volume and promoted compact morphology. Notably, migration was initially similar across genotypes but increased in IDH-mut and 2HG-treated IDH-wt cells over time, though suppressed under therapeutic stress. Conclusions: IDH mutation and 2HG modulate glioma cell biology, including cell cycle dynamics, proliferation rates, migration, and apoptosis. While the IDH mutation and its metabolic product confer initial growth advantages, they enhance treatment sensitivity and reduce invasiveness, highlighting potential vulnerabilities for targeted therapy. Full article

Introduction: Allergic rhinitis (AR) is largely driven by IgE-induced immune cell activation, which promotes allergen-induced upper airway inflammation. The regulatory mechanisms of IgE synthesis in AR are poorly understood. Several analyses associate single nucleotide polymorphisms (SNPs) which reduce the expression of the D2HGDH gene with AR. D2HGDH encodes an enzyme that converts D-2-hydroxyglutarate (D2HG) to α-ketoglutarate (α-KG). This study aims to clarify the relationship between AR and SNPs in D2HGDH. Methods: Mice were treated with vehicle control or octyl-D2HG prior to intranasal exposure to Alternaria alternata. Draining lymph nodes (dLNs) were then evaluated for IgE-producing cells and T-cell polarization. Next, mice were exposed to intranasal Alternaria on days 0, 10, 20, and 27–30 and were treated intranasally with octyl-D2HG or vehicle control on days 20 and 27. Nasal inflammation was analyzed in nasal lavage fluid (NLF) cellularity and antigen-specific IgE production. Results: The administration of D2HG prior to Alternaria exposure suppressed IgE synthesis (p < 0.01) and Th2 cell polarization (p < 0.01) in dLNs. In a murine model of AR, D2HG administration reduced overall cellular infiltrates and eosinophils in NLF. Further, antigen-specific IgE in NLF was significantly reduced in mice treated with D2HG (p < 0.05). Conclusions: An analysis of the regulatory landscape surrounding the rs34290285 SNP demonstrates that the downregulation of D2HGDH expression reduces the risk of AR. Downregulation of D2HGDH likely results in accumulation of D2HG intracellularly, suggesting that D2HG is protective against allergic rhinitis. We show that the administration of D2HG impairs IgE production, leading to the amelioration of allergic sinonasal inflammation in a murine model of AR. These findings suggest a causal relationship between D2HGDH expression, D2HG levels, and allergic rhinitis risk. Full article

The hydroxylated perhydroquinoxaline 14 was designed by conformational restriction of the prototypical κ receptor agonist U-50,488 and the introduction of an additional polar group. The synthesis of 14 comprised ten reaction steps starting from diethyl 3-hydroxyglutarate (4). The first key step was the diastereoselective establishment of the tetrasubstituted cyclohexane 7 by the reaction of dialdehyde 6 with benzylamine and nitromethane. The piperazine ring was annulated by the reaction of silyloxy-substituted cyclohexanetriamine 8 with dimethyl oxalate. The pharmacophoric structural elements characteristic for κ receptor agonists were finally introduced by functional group modifications. The structure including the relative configuration of the tetrasubstituted cyclohexane derivative (2r,5s)-7a and the perhydroquinoxaline 9 was determined unequivocally by X-ray crystal structure analysis. The hydroxylated perhydroquinoxaline 14 showed moderate κ receptor affinity (K_i = 599 nM) and high selectivity over μ, δ, σ₁, and σ₂ receptors. An ionic interaction between the protonated pyrrolidine of 14 and D138 of κ receptor anchors 14 in the κ receptor binding pocket. Full article

In 2021, the World Health Organization classified isocitrate dehydrogenase (IDH) mutant gliomas as a distinct subgroup of tumors with genetic changes sufficient to enable a complete diagnosis. Patients with an IDH mutant glioma have improved survival which has been further enhanced by the advent of targeted therapies. IDH enzymes contribute to cellular metabolism, and mutations to specific catalytic residues result in the neomorphic production of D-2-hydroxyglutarate (D-2-HG). The accumulation of D-2-HG results in epigenetic alterations, oncogenesis and impacts the tumor microenvironment via immunological modulations. Here, we summarize the molecular, cellular, and clinical implications of IDH mutations in gliomas as well as current diagnostic techniques. Full article

Intrahepatic cholangiocarcinoma (ICC) is a universally lethal malignancy with increasing incidence. However, ICC patients receive limited benefits from current drugs; therefore, we must urgently explore new drugs for treating ICC. Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, can suppress cancer cell growth via numerous mechanisms and have therapeutic effects on liver-related diseases. However, the impact of quinolizidine alkaloids on intrahepatic cholangiocarcinoma has not been fully studied. In this article, the in vitro anti-ICC activities of six natural quinolizidine alkaloids were explored. Aloperine was the most potent antitumor compound among the tested quinolizidine alkaloids, and it preferentially inhibited RBE cells rather than HCCC-9810 cells. Mechanistically, aloperine can potentially decrease glutamate content by inhibiting the hydrolysis of glutamine, reducing D-2-hydroxyglutarate levels and, consequently, leading to preferential growth inhibition in isocitrate dehydrogenase (IDH)-mutant ICC cells. In addition, aloperine preferentially resensitizes RBE cells to 5-fluorouracil, AGI-5198 and olaparib. This article demonstrates that aloperine shows preferential antitumor effects in intrahepatic cholangiocarcinoma cells harboring the mutant IDH1 by decreasing D-2-hydroxyglutarate, suggesting that aloperine could be used as a lead compound or adjuvant chemotherapy drug to treat ICC harboring the mutant IDH. Full article

The isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) enzymes are involved in key metabolic processes in human cells, regulating differentiation, proliferation, and oxidative damage response. IDH mutations have been associated with tumor development and progression in various solid tumors such as glioma, cholangiocarcinoma, chondrosarcoma, and other tumor types and have become crucial markers in molecular classification and prognostic assessment. The intratumoral and serum levels of D-2-hydroxyglutarate (D-2-HG) could serve as diagnostic biomarkers for identifying IDH mutant (IDHmut) tumors. As a result, an increasing number of clinical trials are evaluating targeted treatments for IDH1/IDH2 mutations. Recent studies have shown that the focus of these new therapeutic strategies is not only the neomorphic activity of the IDHmut enzymes but also the epigenetic shift induced by IDH mutations and the potential role of combination treatments. Here, we provide an overview of the current knowledge about IDH mutations in solid tumors, with a particular focus on available IDH-targeted treatments and emerging results from clinical trials aiming to explore IDHmut tumor-specific features and to identify the clinical benefit of IDH-targeted therapies and their combination strategies. An insight into future perspectives and the emerging roles of circulating biomarkers and radiomic features is also included. Full article

Low-grade gliomas (LGGs) are slow-growing tumors in the central nervous system (CNS). Patients characteristically show the onset of seizures or neurological deficits due to the predominant LGG location in high-functional brain areas. As a molecular hallmark, LGGs display mutations in the isocitrate dehydrogenase (IDH) enzymes, resulting in an altered cellular energy metabolism and the production of the oncometabolite D-2-hydroxyglutarate. Despite the remarkable progress in improving the extent of resection and adjuvant radiotherapy and chemotherapy, LGG remains incurable, and secondary malignant transformation is often observed. Therefore, novel therapeutic approaches are urgently needed. In recent years, immunotherapeutic strategies have led to tremendous success in various cancer types, but the effect of immunotherapy against glioma has been limited due to several challenges, such as tumor heterogeneity and the immunologically “cold” tumor microenvironment. Nevertheless, recent preclinical and clinical findings from immunotherapy trials are encouraging and offer a glimmer of hope for treating IDH-mutant LGG patients. Here, we aim to review the lessons learned from trials involving vaccines, T-cell therapies, and IDH-mutant inhibitors and discuss future approaches to enhance the efficacy of immunotherapies in IDH-mutant LGG. Full article

Chondrosarcomas are malignant cartilage-producing tumours that frequently harbour isocitrate dehydrogenase 1 and -2 (IDH) gene mutations. Several studies have confirmed that these mutations are key players in the early stages of cartilage tumour development, but their role in later stages remains ambiguous. The prognostic value of IDH mutations remains unclear and preclinical studies have not identified effective treatment modalities (in)directly targeting these mutations. In contrast, the IDH mutation status is a prognostic factor in other cancers, and IDH mutant inhibitors as well as therapeutic strategies targeting the underlying vulnerabilities induced by IDH mutations seem effective in these tumour types. This discrepancy in findings might be ascribed to a difference in tumour type, elevated D-2-hydroxyglutarate levels, and the type of in vitro model (endogenous vs. genetically modified) used in preclinical studies. Moreover, recent studies suggest that the (epi)genetic landscape in which the IDH mutation functions is an important factor to consider when investigating potential therapeutic strategies or patient outcomes. These findings imply that the dichotomy between IDH wildtype and mutant is too simplistic and additional subgroups indeed exist within chondrosarcoma. Future studies should focus on the identification, characterisation, and tailoring of treatments towards these biological subgroups within IDH wildtype and mutant chondrosarcoma. Full article

Altered metabolism is a common feature of many cancers and, in some cases, is a consequence of mutation in metabolic genes, such as the ones involved in the TCA cycle. Isocitrate dehydrogenase (IDH) is mutated in many gliomas and other cancers. Physiologically, IDH converts isocitrate to α-ketoglutarate (α-KG), but when mutated, IDH reduces α-KG to D2-hydroxyglutarate (D2-HG). D2-HG accumulates at elevated levels in IDH mutant tumours, and in the last decade, a massive effort has been made to develop small inhibitors targeting mutant IDH. In this review, we summarise the current knowledge about the cellular and molecular consequences of IDH mutations and the therapeutic approaches developed to target IDH mutant tumours, focusing on gliomas. Full article