Heterogeneity of glutamine metabolism in acquired-EGFR-TKI-resistant lung cancer

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.

Glutamine's double-edged sword: fueling tumor growth and offering therapeutic hope

Tumor metabolic reprogramming is a highly complex process that enables tumor survival in the presence of limited nutrients, involving multiple signaling pathways, non-coding RNAs (ncRNAs), and transcription factors. Lately, glutamine has been found to enhance the growth, spread, and drug resistance of cancer cells, while also fostering an immunosuppressive microenvironment that aids tumor development. However, in some tumors, such as pancreatic cancer and melanoma, additional glutamine can inhibit the proliferation of tumor cells, and this mechanism is closely related to the regulation of the immune microenvironment. Therefore, further exploration of glutamine metabolism in tumors is essential for understanding the pathogenesis of cancer and for developing new metabolically targeted therapies. We systematically review the latest research on the reprogramming of glutamine metabolism and its role of tumor growth, spread, and immune system regulation. Additionally, we review the clinical research progress on targeted glutamine therapies and their application in combination with current anti-tumor treatments. Ultimately, we address the challenges and prospects involved in resistance to anti-cancer strategies aimed at glutamine metabolism.

Dickkopf-1 promotes tumor progression of gefitinib- resistant non-small cell lung cancer through cancer cell-fibroblast interactions

BACKGROUND

Cancer cell-secreted proteins play a critical role in tumor progression and chemoresistance by influencing intercellular interactions within the tumor microenvironment. Investigating the intratumoral functions of these secretory proteins may provide insights into understanding and treating chemoresistant cancers. This study aims to identify potential anticancer target(s) in gefitinib-resistant non-small cell lung cancer (NSCLC), with a focus on secretory proteins and their effects on intercellular interactions.

METHODS

Differentially expressed secretory proteins were identified in gefitinib-resistant human NSCLC cell lines (PC9-GR and HCC827-GR), revealing an elevation in Dickkopf-1 (DKK1) expression and secretion. To elucidate the role of DKK1 in gefitinib-resistant cancer, the anticancer effects of a neutralizing antibody against DKK1 were evaluated in tumors comprising either cancer cells alone or cancer cells co-injected with human lung fibroblasts (MRC-5). Following the confirmation of the importance of cancer cell-fibroblast interactions in the protumorigenic activity of DKK1, the fibroblast traits modulated by DKK1 were further analyzed.

RESULTS

Gefitinib-resistant NSCLC cells exhibited increased DKK1 protein expression. Although elevated DKK1 levels were linked to poor prognosis, DKK1 did not directly affect cancer cell proliferation. However, DKK1 blockade showed significant anticancer effects in gefitinib-resistant tumors containing lung fibroblasts, suggesting that DKK1's pro-tumorigenic roles are mediated through cancer cell-fibroblast interactions. DKK1 altered fibroblast characteristics, enhancing inflammatory fibroblast traits while diminishing myofibroblast traits in tumor microenvironment. These DKK1-induced changes were mediated via activation of the c-JUN pathway in fibroblasts. Moreover, DKK1 was identified as a potential anticancer target across various cancer types beyond gefitinib-resistant lung cancer.

CONCLUSIONS

This study clarifies that DKK1 mediates interactions between cancer cells and fibroblasts in gefitinib-resistant lung cancer, contributing to tumor progression. Therefore, we propose DKK1 as a promising anticancer target for the treatment of gefitinib-resistant NSCLC.

Scutellarein inhibits lung cancer growth by inducing cell apoptosis and inhibiting glutamine metabolic pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria baicalensis Georgi, a widely used Chinese medicinal herb, has shown effectiveness against lung cancer. Scutellarein, a key component of Scutellaria baicalensis, also demonstrates anticancer properties in lung cancer. However, the underlying mechanisms have not yet been clarified.

AIM OF THE STUDY

This study aimed to investigate the effects of scutellarein in the treatment of NSCLC and its underlying mechanisms.

METHODS

This study explored the effects of scutellarein on non-small cell lung cancer (NSCLC) and its mechanisms. A Lewis lung cancer mouse model was established to assess scutellarein's anticancer activity in vivo. Additionally, the compound's effects on cell proliferation, colony formation, migration, and apoptosis were evaluated in vitro using A549 and H1299 lung cancer cells. Metabolomics analysis was conducted to identify changes in cellular metabolism due to scutellarein, while molecular docking and western blotting techniques were employed to elucidate the molecular mechanisms of its anti-lung cancer effects.

RESULTS

Scutellarein significantly inhibited lung cancer xenograft tumor growth. In vitro studies showed that scutellarein suppressed migration and colony formation in A549 and H1299 cells, induced cell cycle arrest, and triggered cell apoptosis. Notably, scutellarein profoundly altered amino acid metabolism, particularly affecting glutamine metabolites. It affected key glutamine transporters ASCT2 and LAT1, as well as glutaminase GLS1, leading to their reduced expression.

CONCLUSION

Scutellarein effectively inhibits lung cancer growth both in vivo and in vitro by inducing cell apoptosis and downregulating the glutamine metabolic pathway.

Single-Cell Mass Spectrometry Studies of Secondary Drug Resistance of Tumor Cells

Patients with epidermal growth factor receptor mutant nonsmall cell lung cancer (NSCLC) often fail to treat gefitinib because of secondary drug resistance. The development of tumor drug resistance is closely related to variations in cancer cell metabolism. Single-cell metabolomics analysis can provide unique information about tumor drug resistance. Herein, we constructed a platform to study the secondary resistance of tumor cells based on single-cell metabolomics (sSRTC-scM). A gefitinib-resistant NSCLC cell line (PC9GR) was constructed by increasing the dose step by step. The metabolic profiles of parental PC9 cells and PC9GR cells with different drug resistance levels were detected by intact living-cell electrolaunching ionization mass spectrometry at the single-cell level. The data were analyzed by statistical methods such as t-SNE, variance, volcano plot, heat map, and metabolic pathway analysis. Using this platform, we found that the metabolic fingerprints of PC9GR cells can evaluate drug resistance degrees. The metabolic fingerprints continue to be altered with the increase of drug resistance. We revealed 19 metabolic markers of secondary resistance by variance analysis and clarified that the glycerophospholipid metabolic pathway of PC9GR cells changed significantly. In addition, we found that with the increase in drug resistance levels, the heterogeneity of single-cell metabolism became greater and the number of cells with weak drug resistance gradually decreased. This phenomenon can be utilized to illustrate the drug resistance degrees of PC9GR cells. This study provides diagnostic markers for evaluating the drug resistance of tumors and gives new insight into overcoming the secondary resistance of tumors.

Metabolomics-driven approaches for identifying therapeutic targets in drug discovery

Identification of therapeutic targets can directly elucidate the mechanism and effect of drug therapy, which is a central step in drug development. The disconnect between protein targets and phenotypes under complex mechanisms hampers comprehensive target understanding. Metabolomics, as a systems biology tool that captures phenotypic changes induced by exogenous compounds, has emerged as a valuable approach for target identification. A comprehensive overview was provided in this review to illustrate the principles and advantages of metabolomics, delving into the application of metabolomics in target identification. This review outlines various metabolomics-based methods, such as dose-response metabolomics, stable isotope-resolved metabolomics, and multiomics, which identify key enzymes and metabolic pathways affected by exogenous substances through dose-dependent metabolite-drug interactions. Emerging techniques, including single-cell metabolomics, artificial intelligence, and mass spectrometry imaging, are also explored for their potential to enhance target discovery. The review emphasizes metabolomics' critical role in advancing our understanding of disease mechanisms and accelerating targeted drug development, while acknowledging current challenges in the field.

The combined inhibition of SLC1A3 and glutaminase in osimertinib-resistant EGFR mutant cells

BACKGROUND

We investigated the unknown mechanisms of osimertinib-resistant EGFR-mutant lung cancer.

METHODS

An osimertinib-resistant cell line (PC-9/OsmR2) was established through continuous exposure to osimertinib using an EGFR exon 19 deletion (19Del) lung adenocarcinoma cell line (PC-9). EGFR 19Del (M1), L858R/T790M/C797S (M6), and L858R/C797S (M8) expression vectors were introduced into Ba/F3 cells. A second osimertinib-resistant line (M1/OsmR) was established through continuous exposure to osimertinib using M1 cells.

RESULTS

SLC1A3 had the highest mRNA expression level in PC-9/OsmR2 compared to PC-9 cells by microarray analysis and SLC1A3 was increased by flow cytometry. In PC-9/OsmR2 cells, osimertinib sensitivity was significantly increased in combination with siSLC1A3. Because SLC1A3 functions in glutamic acid transport, osimertinib with a glutaminase inhibitor (CB-839) or an SLC1A3 inhibitor (TFB-TBOA) increased the sensitivity. Also, CB-839 plus TFB-TBOA without osimertinib resulted in greater susceptibility than did CB-839 or TFB-TBOA plus osimertinib. Comprehensive metabolome analysis showed that the M1/OsmR cells had significantly more glutamine and glutamic acid than M1 cells. CB-839 plus osimertinib exerted a synergistic effect on M6 cells and an additive effect on M8 cells.

CONCLUSION

Targeting glutaminase and glutamic acid may overcome the osimertinib-resistant EGFR-mutant lung cancer.

Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Stable Isotope Tracing Analysis in Cancer Research: Advancements and Challenges in Identifying Dysregulated Cancer Metabolism and Treatment Strategies

Metabolic reprogramming is a hallmark of cancer, driving the development of therapies targeting cancer metabolism. Stable isotope tracing has emerged as a widely adopted tool for monitoring cancer metabolism both in vitro and in vivo. Advances in instrumentation and the development of new tracers, metabolite databases, and data analysis tools have expanded the scope of cancer metabolism studies across these scales. In this review, we explore the latest advancements in metabolic analysis, spanning from experimental design in stable isotope-labeling metabolomics to sophisticated data analysis techniques. We highlight successful applications in cancer research, particularly focusing on ongoing clinical trials utilizing stable isotope tracing to characterize disease progression, treatment responses, and potential mechanisms of resistance to anticancer therapies. Furthermore, we outline key challenges and discuss potential strategies to address them, aiming to enhance our understanding of the biochemical basis of cancer metabolism.

Discovery of Novel Aminobutanoic Acid-Based ASCT2 Inhibitors for the Treatment of Non-Small-Cell Lung Cancer

Alanine-serine-cysteine transporter 2 (ASCT2) is up-regulated in lung cancers, and inhibiting it could potentially lead to nutrient deprivation, making it a viable strategy for cancer treatment. In this study, we present a series of ASCT2 inhibitors based on aminobutanoic acids, which exhibit potent inhibitory activity. Two compounds, 20k and 25e, were identified as novel and potent ASCT2 inhibitors, with IC50 values at the micromolar level in both A549 and HEK293 cells, effectively blocking glutamine (Gln) uptake. Additionally, these compounds regulated amino acid metabolism, suppressed mTOR signaling, inhibited non-small-cell lung cancer (NSCLC) growth, and induced apoptosis. In vivo, experiments showed that 20k and 25e suppressed tumor growth in an A549 xenograft model, with tumor growth inhibition (TGI) values of 65 and 70% at 25 mg/kg, respectively, while V9302 only achieved a TGI value of 29%. Furthermore, both compounds demonstrated promising therapeutic potential in patient-derived organoids. Therefore, these ASCT2 inhibitors based on aminobutanoic acids are promising therapeutic agents for treating NSCLC by targeting cancer Gln metabolism.

Two Faces of Glutaminase GLS2 in Carcinogenesis

In rapidly proliferating cancer cells, glutamine is a major source of energy and building blocks. Increased glutamine uptake and enhanced glutaminolysis are key metabolic features of many cancers. Glutamine is metabolized by glutaminase (GA), which is encoded by two genes: GLS and GLS2. In contrast to isoforms arising from the GLS gene, which clearly act as oncoproteins, the role of GLS2 products in tumorigenesis is far from well understood. While in some cancer types GLS2 is overexpressed and drives cancer development, in some other types it is downregulated and behaves as a tumor suppressor gene. In this review, we describe the essential functions and regulatory mechanisms of human GLS2 and the cellular compartments in which GLS2 has been localized. Furthermore, we present the context-dependent oncogenic and tumor-suppressor properties of GLS2, and delve into the mechanisms underlying these phenomena.