P2X1 enhances leukemogenesis through PBX3-BCAT1 pathways

Multiple roles of branched-chain amino acid metabolism in tumour progression

Metabolic reprogramming enables tumour cells to sustain their continuous proliferation and adapt to the ever-changing microenvironment. Branched-chain amino acids (BCAAs) and their metabolites are involved in intracellular protein synthesis and catabolism, signal transduction, epigenetic modifications, and the maintenance of oxidative homeostasis. Alterations in BCAA metabolism can influence the progression of various tumours. However, how BCAA metabolism is dysregulated differs among depending on tumour type; for example, it can manifest as decreased BCAA metabolism leading to BCAA accumulation, or as enhanced BCAA uptake and increased catabolism. In this review, we describe the role of BCAA metabolism in the progression of different tumours. As well as discuss how BCAA metabolic reprogramming drives tumour therapy resistance and evasion of the antitumour immune response, and how these pro-cancer effects are achieved in part by activating the mTORC signalling pathway. In-depth investigations into the potential mechanisms by which BCAA metabolic reprogramming affects tumorigenesis and tumour progression can enhance our understanding of the relationship between metabolism and cancer and provide new strategies for cancer therapy.

Fueling the fight against cancer: Exploring the impact of branched-chain amino acid catalyzation on cancer and cancer immune microenvironment

Metabolism of Branched-chain amino acids (BCAAs) is essential for the nutrient necessities in mammals. Catalytic enzymes serve to direct the whole-body BCAAs oxidation which involve in the development of various metabolic disorders. The reprogrammed metabolic elements are also responsible for malignant oncogenic processes, and favor the formation of distinctive immunosuppressive microenvironment surrounding different cancers. The impotent immune surveillance related to BCAAs dysfunction is a novel topic to investigate. Here we focus on the BCAA catalysts that contribute to metabolic changes and dysregulated immune reactions in cancer progression. We summarize the current knowledge of BCAA catalyzation, highlighting the interesting roles of BCAA metabolism in the treatment of cancers.

Structural insights into the human P2X1 receptor and ligand interactions

The P2X1 receptor is a trimeric ligand-gated ion channel that plays an important role in urogenital and immune functions, offering the potential for new drug treatments. However, progress in this area has been hindered by limited structural information and a lack of well-characterised tool compounds. In this study, we employ cryogenic electron microscopy (cryo-EM) to elucidate the structures of the P2X1 receptor in an ATP-bound desensitised state and an NF449-bound closed state. NF449, a potent P2X1 receptor antagonist, engages the receptor distinctively, while ATP, the endogenous ligand, binds in a manner consistent with other P2X receptors. To explore the molecular basis of receptor inhibition, activation, and ligand interactions, key residues involved in ligand and metal ion binding were mutated. Radioligand binding assays with [3H]-α,β-methylene ATP and intracellular calcium ion influx assays were used to evaluate the effects of these mutations. These experiments validate key ligand-receptor interactions and identify conserved and non-conserved residues critical for ligand binding or receptor modulation. This research expands our understanding of the P2X1 receptor structure at a molecular level and opens new avenues for in silico drug design targeting the P2X1 receptor.

RUNX1::ETO and CBFβ::MYH11 converge on aberrant activation of BCAT1 to confer a therapeutic vulnerability in core-binding factor-acute myeloid leukaemia

Effectively targeting transcription factors in therapeutic interventions remains challenging, especially in core-binding factor-acute myeloid leukaemia (CBF-AML) characterized by RUNX1::ETO and CBFβ::MYH11 fusions. However, recent studies have drawn attention towards aberrant amino acid metabolisms as actionable therapeutic targets. Here, by integrating the expression profile and genetic makeup in AML cohort, we found higher BCAT1 expression in CBF-AML patients compared with other subtypes. Metabolic profiling revealed that high BCAT1 expression led to reprogrammed branch amino acid metabolism in CBF-AML and was associated with sphingolipid pathway relating to the fitness of leukaemia cells, supported by transcriptomic profiling. Mechanistically, we demonstrated in cell lines and primary patient samples that BCAT1 was directly activated by RUNX1::ETO and CBFβ::MYH11 fusion proteins similarly in a RUNX1-dependent manner through rewiring chromatin conformation at the BCAT1 gene locus. Furthermore, BCAT1 inhibition resulted in blunted cell cycle, enhanced apoptosis and myeloid differentiation of CBF-AML cells in vitro, and alleviated leukaemia burden and prolonged survival in vivo. Importantly, pharmacological inhibition of BCAT1 using the specific inhibitor Gabapentin demonstrated therapeutic effects, as evidenced by delayed leukaemia progression and improved survival in vivo. In conclusion, our study uncovers BCAT1 as a genetic vulnerability and a promising targeted therapeutic opportunity for CBF-AML.

Advances in the role of ion channels in leukemia

Ion channels are widely present in cell membranes, serving as crucial pathways for the movement of ions enter and exit cells. Variations in the expression of ion channels are crucial for regulating cellular functions. Among the genes associated with leukemia, certain genes encode ion channels. When these ion channels experience dysfunction or changes in expression, they can impact the physiological functions and signal transduction of hematopoietic cells, thereby regulating leukemia cell proliferation, differentiation, invasion/migration, and apoptosis. This article will provide a comprehensive review of the research progress on the expression and function of various ion channels in leukemia, thoroughly exploring their roles and mechanisms in the onset and progression of the disease, providing new insights and ideas for identifying potential biomarkers and developing new treatment methods for leukemia, thereby promoting innovations in future leukemia diagnosis and therapy.

Cross-talk between BCKDK-mediated phosphorylation and STUB1-dependent ubiquitination degradation of BCAT1 promotes GBM progression

Branched-chain amino acid transferase 1 (BCAT1) is highly expressed in multiple cancers and is associated with poor prognosis, particularly in glioblastoma (GBM). However, the post-translational modification (PTM) mechanism of BCAT1 is unknown. Here, we investigated the cross-talk mechanisms between phosphorylation and ubiquitination modifications in regulating BCAT1 activity and stability. We found that BCAT1 is phosphorylated by branched chain ketoacid dehydrogenase kinase (BCKDK) at S5, S9, and T312, which increases its catalytic and antioxidant activity and stability. STUB1 (STIP1 homology U-box-containing protein 1), the first we found and reported E3 ubiquitin ligase of BCAT1, can also be phosphorylated by BCKDK at the S19 site, which disrupts the interaction with BCAT1 and inhibits its degradation. In addition, we demonstrate through in vivo and in vitro experiments that BCAT1 phosphorylation inhibiting its ubiquitination at multiple sites is associated with GBM proliferation and that inhibition of the BCKDK-BCAT1 axis enhances the sensitivity to temozolomide (TMZ). Overall, we identified novel mechanisms for the regulation of BCAT1 modification and elucidated the importance of the BCKDK-STUB1-BCAT1 axis in GBM progression.

Purinergic pathways and their clinical use in the treatment of acute myeloid leukemia

Despite the use of various therapies such as hematopoietic stem cell transplantation and chimeric antigen receptor T cell therapy (CAR-T), the prognosis of patients with acute myeloid leukemia (AML) is still generally poor. However, immunotherapy is currently a hot topic in the treatment of hematological tumors. Extracellular adenosine triphosphate (ATP) can be converted to adenosine diphosphate (ADP) via CD39, and ADP can be converted to adenosine via CD73, which can bind to P1 and P2 receptors to exert immunomodulatory effects. Research on the mechanism of the purinergic signaling pathway can provide a new direction for the treatment of AML, and inhibitors of this signaling pathway have been discovered by several researchers and gradually applied in the clinic. In this paper, the mechanism of the purinergic signaling pathway and its clinical application are described, revealing a new target for the treatment of AML and subsequent improvement in patient prognosis.

GTAC enables parallel genotyping of multiple genomic loci with chromatin accessibility profiling in single cells

Understanding clonal evolution and cancer development requires experimental approaches for characterizing the consequences of somatic mutations on gene regulation. However, no methods currently exist that efficiently link high-content chromatin accessibility with high-confidence genotyping in single cells. To address this, we developed Genotyping with the Assay for Transposase-Accessible Chromatin (GTAC), enabling accurate mutation detection at multiple amplified loci, coupled with robust chromatin accessibility readout. We applied GTAC to primary acute myeloid leukemia, obtaining high-quality chromatin accessibility profiles and clonal identities for multiple mutations in 88% of cells. We traced chromatin variation throughout clonal evolution, showing the restriction of different clones to distinct differentiation stages. Furthermore, we identified switches in transcription factor motif accessibility associated with a specific combination of driver mutations, which biased transformed progenitors toward a leukemia stem cell-like chromatin state. GTAC is a powerful tool to study clonal heterogeneity across a wide spectrum of pre-malignant and neoplastic conditions.