A Novel ASCT2 Inhibitor, C118P, Blocks Glutamine Transport and Exhibits Antitumour Efficacy in Breast Cancer

A hormetic response model for glutamine stress in cancer

Glutamine metabolism supports the development and progression of many cancers and is considered a therapeutic target. Attempts to inhibit glutamine metabolism have resulted in limited success and have not translated into clinical benefit. The outcomes of these clinical studies, along with preclinical investigations, suggest that cellular stress responses to glutamine deprivation or targeting may be modeled as a biphasic hormetic response. By recognizing the multifaceted aspects of glutamine metabolism inhibition within a more comprehensive biological framework, the adoption of this model may guide future fundamental and translational studies. To achieve clinical efficacy, we posit that as a field we will need to anticipate the hormetic effects of glutamine stress and consider how best to co-target cancer cell adaptive mechanisms.

Metabolism and spatial transcription resolved heterogeneity of glutamine metabolism in cervical carcinoma

BACKGROUND

Reprogramming of cellular metabolism is a pivotal mechanism employed by tumor cells to facilitate cell growth, proliferation, and differentiation, thereby propelling the progression of cancer. A comprehensive analysis of the transcriptional and metabolic landscape of cervical squamous cell carcinoma (CSCC) at high resolution could greatly enhance the precision of management and therapeutic strategies for this malignancy.

METHODS

The Air-flow-assisted Desorption Electrospray Ionization Mass Spectro-metric Imaging (AFADESI-MSI) and Spatial Transcriptomics techniques (ST) were employed to investigate the metabolic and transcription profiles of CSCC and normal tissues. For clinical validation, the expression of ASCT2(Ala, Ser, Cys transporter 2) was assessed using immune histochemistry in 122 cases of cervical cancer and 30 cases of cervicitis.

RESULTS

The AFADESI-MSI findings have revealed metabolic differences among different CSCC patients. Among them, the metabolic pathways of glutamine show more significant differences. After in situ detection of metabolites, the intensity of glutamate is observed to be significantly higher in cancerous tissue compared to normal tissue, but the intensity is not uniform. To elucidate the potential factors underlying alterations in glutamine metabolism across tissues, we employ ST to quantify mRNA levels. This analysis unveils significant perturbations in glutamine metabolism accompanied by extensive heterogeneity within cervical cancer tissues. After conducting a comprehensive analysis, it has been revealed that the differential expression of ASCT2(encoded by SLC1A5) in distinct regions of cervical cancer tissues plays a pivotal role in inducing heterogeneity in glutamine metabolism. Furthermore, the higher the expression level of ASCT2, the higher the intensity of glutamate is in the region. Further verification, it is found that the expression of ASCT2 protein in CSCC tissues is significantly higher than that in normal tissues (105/122, 86.07%).

CONCLUSIONS

This finding suggests that the variation in glutamine metabolism is not uniform throughout the tumor. The differential expression of ASCT2 in different regions of cervical cancer tissues seems to play a key role in causing this heterogeneity. This research has opened up new avenues for exploring the glutamine metabolic characteristics of CSCC which is essential for developing more effective targeted therapies.

Research status and potential applications of circRNAs affecting colorectal cancer by regulating ferroptosis

Ferroptosis is an emerging form of non-apoptotic programmed cell death (PCD), characterized by iron-mediated oxidative imbalance. This process plays a significant role in the development and progression of various tumors, including colorectal cancer, gastric cancer, and others. Circular RNA (circRNA) is a stable, non-coding RNA type with a single-stranded, covalently closed loop structure, which is intricately linked to the proliferation, invasion, and metastasis of tumor cells. Recent studies have shown that many circRNAs regulate various pathways leading to cellular ferroptosis. Colorectal cancer, known for its high incidence and mortality among cancers, is marked by a poor prognosis and pronounced chemoresistance. To enhance our understanding of how circRNA-mediated regulation of ferroptosis influences colorectal cancer development, this review systematically examines the mechanisms by which specific circRNAs regulate ferroptosis and their critical role in the progression of colorectal cancer. Furthermore, it explores the potential of circRNAs as biomarkers and therapeutic targets in colorectal cancer treatment, offering a novel approach to clinical management.

Validation of shikimate dehydrogenase as the herbicidal target of drupacine and screening of target-based compounds with high herbicidal activity

The discovery of new targets and lead compounds is the key to developing new pesticides. The herbicidal target of drupacine has been identified as shikimate dehydrogenase (SkDH). However, the mechanism of interaction between them remains unclear. This study found that drupacine specifically binds to SkDH with a dissociation equilibrium constant (KD) of 8.88 μM and a Kd value of 2.15 μM, as confirmed by surface plasmon resonance and microscale thermophoresis. Site-directed mutagenesis coupled with fluorescence quenching analysis indicated that residue THR431 was the key amino acid site for drupacine binding to SkDH. Nine compounds with the best binding ability to SkDH were identified by virtual screening from about 120,000 compounds. Among them, compound 8 showed the highest inhibition rate with values of 41.95% against SkDH, also exhibiting the strongest herbicidal activity. This research identifies a novel potential target SkDH and a candidate lead compound with high herbicidal activity for developing new herbicides.

ASCT2 Regulates Fatty Acid Metabolism to Trigger Glutamine Addiction in Basal-like Breast Cancer

As a crucial amino acid, glutamine can provide the nitrogen and carbon sources needed to support cancer cell proliferation, invasion, and metastasis. Interestingly, different types of breast cancer have different dependences on glutamine. This research shows that basal-like breast cancer depends on glutamine, while the other types of breast cancer may be more dependent on glucose. Glutamine transporter ASCT2 is highly expressed in various cancers and significantly promotes the growth of breast cancer. However, the key regulatory mechanism of ASCT2 in promoting basal-like breast cancer progression remains unclear. Our research demonstrates the significant change in fatty acid levels caused by ASCT2, which may be a key factor in glutamine sensitivity. This phenomenon results from the mutual activation between ASCT2-mediated glutamine transport and lipid metabolism via the nuclear receptor PPARα. ASCT2 cooperatively promoted PPARα expression, leading to the upregulation of lipid metabolism. Moreover, we also found that C118P could inhibit lipid metabolism by targeting ASCT2. More importantly, this research identifies a potential avenue of evidence for the prevention and early intervention of basal-like breast cancer by blocking the glutamine-lipid feedback loop.

Glutaminolysis is a Potential Therapeutic Target for Kidney Diseases

Metabolic reprogramming contributes to the progression and prognosis of various kidney diseases. Glutamine is the most abundant free amino acid in the body and participates in more metabolic processes than other amino acids. Altered glutamine metabolism is a prominent feature in different kidney diseases. Glutaminolysis converts glutamine into the TCA cycle metabolite, alpha-ketoglutarate, via a cascade of enzymatic reactions. This metabolic pathway plays pivotal roles in inflammation, maladaptive repair, cell survival and proliferation, redox homeostasis, and immune regulation. Given the crucial role of glutaminolysis in bioenergetics and anaplerotic fluxes in kidney pathogenesis, studies on this cascade could provide a better understanding of kidney diseases, thus inspiring the development of potential methods for targeted therapy. Emerging evidence has shown that targeting glutaminolysis is a promising therapeutic strategy for ameliorating kidney disease. In this narrative review, equation including keywords related to glutamine, glutaminolysis and kidney are subjected to an exhaustive search on Pubmed database, we identified all relevant articles published before 1 April, 2024. Afterwards, we summarize the regulation of glutaminolysis in major kidney diseases and its underlying molecular mechanisms. Furthermore, we highlight therapeutic strategies targeting glutaminolysis and their potential clinical applications.

Exploiting the Achilles' heel of cancer: disrupting glutamine metabolism for effective cancer treatment

Cancer cells have adapted to rapid tumor growth and evade immune attack by reprogramming their metabolic pathways. Glutamine is an important nitrogen resource for synthesizing amino acids and nucleotides and an important carbon source in the tricarboxylic acid (TCA) cycle and lipid biosynthesis pathway. In this review, we summarize the significant role of glutamine metabolism in tumor development and highlight the vulnerabilities of targeting glutamine metabolism for effective therapy. In particular, we review the reported drugs targeting glutaminase and glutamine uptake for efficient cancer treatment. Moreover, we discuss the current clinical test about targeting glutamine metabolism and the prospective direction of drug development.