Metabolic reservoir cycles in cancer

Radiation-induced exosomes promote oral squamous cell carcinoma progression via enhancing SLC1A5-glutamine metabolism

BACKGROUND

Radiotherapy (RT) can drive cancer cells to enter a state of cellular senescence in which cells can secrete senescence-associated secretory phenotype (SASP) and produce small extracellular vesicles (sEVs) to interact with cells in the tumor microenvironment (TME). Tumor-derived sEVs that are taken up by recipient cells contribute to cancer cell metabolic plasticity, resistance to anticancer therapy, and adaptation to the TME. However, how radiation-induced sEVs support oral squamous cell carcinoma (OSCC) progression remains unclear.

METHODS

Beta-galactosidase staining and SASP mRNA expression analysis were used to evaluate the senescence-associated activity of OSCC cells after irradiation. Nanoparticle tracking analysis was performed to identify radiation-induced sEVs. Liquid chromatography-tandem mass spectrometry (LC-MS) was used to explore changes in the levels of proteins in radiation-induced sEVs. Cell Counting Kit-8 and colony formation assays were performed to investigate the function of radiation-induced SASP and sEVs in vitro. A xenograft tumor model was established to investigate the functions of radiation-induced sEVs and V-9302 in vivo as well as the underlying mechanisms. Bioinformatics analysis was performed to determine the relationship between glutamine metabolism and OSCC recurrence.

RESULTS

We determined that the radiation-induced SASP triggered OSCC cell proliferation. Additionally, radiation-induced sEVs exacerbated OSCC cell malignancy. LC-MS/MS and bioinformatics analyses revealed that SLC1A5, which is a cellular receptor that participates in glutamine uptake, was significantly enriched in radiation-induced sEVs. In vitro and in vivo, inhibiting SLC1A5 could block the oncogenic effects of radiation-induced sEVs in OSCC.

CONCLUSION

Radiation-induced sEVs might promote the proliferation of unirradiated cancer cells by enhancing glutamine metabolism; this might be a novel molecular mechanism underlying radiation resistance in OSCC patients.

Functional synergy of a human-specific and an ape-specific metabolic regulator in human neocortex development

Metabolism has recently emerged as a major target of genes implicated in the evolutionary expansion of human neocortex. One such gene is the human-specific gene ARHGAP11B. During human neocortex development, ARHGAP11B increases the abundance of basal radial glia, key progenitors for neocortex expansion, by stimulating glutaminolysis (glutamine-to-glutamate-to-alpha-ketoglutarate) in mitochondria. Here we show that the ape-specific protein GLUD2 (glutamate dehydrogenase 2), which also operates in mitochondria and converts glutamate-to-αKG, enhances ARHGAP11B's ability to increase basal radial glia abundance. ARHGAP11B + GLUD2 double-transgenic bRG show increased production of aspartate, a metabolite essential for cell proliferation, from glutamate via alpha-ketoglutarate and the TCA cycle. Hence, during human evolution, a human-specific gene exploited the existence of another gene that emerged during ape evolution, to increase, via concerted changes in metabolism, progenitor abundance and neocortex size.

The role of glutamate and glutamine metabolism and related transporters in nerve cells

BACKGROUND

Glutamate and glutamine are the most abundant amino acids in the blood and play a crucial role in cell survival in the nervous system. Various transporters found in cell and mitochondrial membranes, such as the solute carriers (SLCs) superfamily, are responsible for maintaining the balance of glutamate and glutamine in the synaptic cleft and within cells. This balance affects the metabolism of glutamate and glutamine as non-essential amino acids.

AIMS

This review aims to provide an overview of the transporters and enzymes associated with glutamate and glutamine in neuronal cells.

DISCUSSION

We delve into the function of glutamate and glutamine in the nervous system by discussing the transporters involved in the glutamate-glutamine cycle and the key enzymes responsible for their mutual conversion. Additionally, we highlight the role of glutamate and glutamine as carbon and nitrogen donors, as well as their significance as precursors for the synthesis of reduced glutathione (GSH).

CONCLUSION

Glutamate and glutamine play a crucial role in the brain due to their special effects. It is essential to focus on understanding glutamate and glutamine metabolism to comprehend the physiological behavior of nerve cells and to treat nervous system disorders and cancer.

Thymic-Epithelial-Cell-Dependent Microenvironment Influences Proliferation and Apoptosis of Leukemic Cells

T-cell acute lymphoblastic leukemia (T-ALL) is a hematological cancer characterized by the infiltration of immature T-cells in the bone marrow. Aberrant NOTCH signaling in T-ALL is mainly triggered by activating mutations of NOTCH1 and overexpression of NOTCH3, and rarely is it linked to NOTCH3-activating mutations. Besides the known critical role of NOTCH, the nature of intrathymic microenvironment-dependent mechanisms able to render immature thymocytes, presumably pre-leukemic cells, capable of escaping thymus retention and infiltrating the bone marrow is still unclear. An important challenge is understanding how leukemic cells shape their tumor microenvironment to increase their ability to infiltrate and survive within. Our previous data indicated that hyperactive NOTCH3 affects the CXCL12/CXCR4 system and may interfere with T-cell/stroma interactions within the thymus. This study aims to identify the biological effects of the reciprocal interactions between human leukemic cell lines and thymic epithelial cell (TEC)-derived soluble factors in modulating NOTCH signaling and survival programs of T-ALL cells and TECs. The overarching hypothesis is that this crosstalk can influence the progressive stages of T-cell development driving T-cell leukemia. Thus, we investigated the effect of extracellular space conditioned by T-ALL cell lines (Jurkat, TALL1, and Loucy) and TECs and studied their reciprocal regulation of cell cycle and survival. In support, we also detected metabolic changes as potential drivers of leukemic cell survival. Our studies could shed light on T-cell/stroma crosstalk to human leukemic cells and propose our culture system to test pharmacological treatment for T-ALL.

Secretion of acetylated amino acids by drug-induced cancer cells: perspectives on metabolic-epigenetic alterations

The emerging understanding of the super-complex and heterogeneous nature of tumor is well supported by metabolic reprogramming, leading survival advantages. Metabolic reprogramming contributes to tumor responsiveness and resistance to various antitumor drugs. Among the numerous adaptations made by cancer cells in response to drug-induced perturbations, key metabolic alterations involving amino acids and acetylated derivatives of amino acids have received special attention. Considering these implications discussed, targeting cancer-associated metabolic pathways, particularly those involving acetylated amino acids, emerges as an important avenue in the pursuit of combinatorial anticancer strategies. As a result, the introduction of mimetic acetylated amino acids represents a promising new class of inhibitors that could be used alongside traditional chemotherapy agents.

Integration of Patient-Derived Organoids and Organ-on-Chip Systems: Investigating Colorectal Cancer Invasion within the Mechanical and GABAergic Tumor Microenvironment

Three-dimensional (3D) in vitro models are essential in cancer research, but they often neglect physical forces. In our study, we combined patient-derived tumor organoids with a microfluidic organ-on-chip system to investigate colorectal cancer (CRC) invasion in the tumor microenvironment (TME). This allowed us to create patient-specific tumor models and assess the impact of physical forces on cancer biology. Our findings showed that the organoid-on-chip models more closely resembled patient tumors at the transcriptional level, surpassing organoids alone. Using 'omics' methods and live-cell imaging, we observed heightened responsiveness of KRAS mutant tumors to TME mechanical forces. These tumors also utilized the γ-aminobutyric acid (GABA) neurotransmitter as an energy source, increasing their invasiveness. This bioengineered model holds promise for advancing our understanding of cancer progression and improving CRC treatments.

How Warburg-Associated Lactic Acidosis Rewires Cancer Cell Energy Metabolism to Resist Glucose Deprivation

Lactic acidosis, a hallmark of solid tumour microenvironment, originates from lactate hyperproduction and its co-secretion with protons by cancer cells displaying the Warburg effect. Long considered a side effect of cancer metabolism, lactic acidosis is now known to play a major role in tumour physiology, aggressiveness and treatment efficiency. Growing evidence shows that it promotes cancer cell resistance to glucose deprivation, a common feature of tumours. Here we review the current understanding of how extracellular lactate and acidosis, acting as a combination of enzymatic inhibitors, signal, and nutrient, switch cancer cell metabolism from the Warburg effect to an oxidative metabolic phenotype, which allows cancer cells to withstand glucose deprivation, and makes lactic acidosis a promising anticancer target. We also discuss how the evidence about lactic acidosis' effect could be integrated in the understanding of the whole-tumour metabolism and what perspectives it opens up for future research.

Role of LDH in tumor glycolysis: Regulation of LDHA by small molecules for cancer therapeutics

Lactate dehydrogenase (LDH) is one of the crucial enzymes in aerobic glycolysis, catalyzing the last step of glycolysis, i.e. the conversion of pyruvate to lactate. Most cancer cells are characterized by an enhanced rate of tumor glycolysis to ensure the energy demand of fast-growing cancer cells leading to increased lactate production. Excess lactate creates extracellular acidosis which facilitates invasion, angiogenesis, and metastasis and affects the immune response. Lactate shuttle and lactate symbiosis is established in cancer cells, which may further increase the poor prognosis. Several genetic and phenotypic studies established the potential role of lactate dehydrogenase A (LDHA) or LDH5, the one homo-tetramer of subunit A, in cancer development and metastasis. The LDHA is considered a viable target for drug design and discovery. Several small molecules have been discovered to date exhibiting significant LDHA inhibitory activities and anticancer activities, therefore the starvation of cancer cells by targeting tumor glycolysis through LDHA inhibition with improved selectivity can generate alternative anticancer therapeutics. This review provides an overview of the role of LDHA in metabolic reprogramming and its association with proto-oncogenes and oncogenes. This review also aims to deliver an update on significant LDHA inhibitors with anticancer properties and future direction in this area.

Identification of Immune and Hypoxia Risk Classifier to Estimate Immune Microenvironment and Prognosis in Cervical Cancer

Purpose

Cervical cancer (CC) is one of the most common gynecologic neoplasms. Hypoxia is an essential trigger for activating immunosuppressive activity and initiating malignant tumors. However, the determination of the role of immunity and hypoxia on the clinical outcome of CC patients remains unclear.

Methods

The CC independent cohort were collected from TCGA database. Consensus cluster analysis was employed to determine a molecular subtype based on immune and hypoxia gene sets. Cox relevant analyses were utilized to set up a risk classifier for prognosis assessment. The underlying pathways of classifier genes were detected by GSEA. Moreover, we conducted CIBERSORT algorithm to mirror the immune status of CC samples.

Results

We observed two cluster related to immune and hypoxia status and found the significant difference in outcome of patients between the two clusters. A total of 251 candidate genes were extracted from the two clusters and enrolled into Cox relevant analyses. Then, seven hub genes (CCL20, CXCL2, ITGA5, PLOD2, PTGS2, TGFBI, and VEGFA) were selected to create an immune and hypoxia-based risk classifier (IHBRC). The IHBRC can precisely distinguish patient risk and estimate clinical outcomes. In addition, IHBRC was closely bound up with tumor associated pathways such as hypoxia, P53 signaling and TGF β signaling. IHBRC was also tightly associated with numerous types of immunocytes.

Conclusion

This academic research revealed that IHBRC can be served as predictor for prognosis assessment and cancer treatment estimation in CC.

Unraveling tumor microenvironment of small-cell lung cancer: implications for immunotherapy

Small-cell lung cancer (SCLC) is an aggressive lung cancer subtype and its first-line treatment has remained unchanged for decades. In recent years, immunotherapy has emerged as a therapeutic strategy for tumor treatment, whereas, patients with SCLC exhibit poor overall responses to immunotherapy alone, which highlights the necessity for combinatorial approaches. The tumor microenvironment (TME), an integral component in cancer, is widely implicated in tumorigenesis and tumor metastasis. The interactions of various cells within TME shape the adverse conditions of the tumor microenvironment (characterized by hypoxia, nutrient restriction, and acidity) and are considered responsible for the modest therapeutic responses to immunotherapy. Several studies have suggested that adverse TME can regulate immune cell activation and function. However, the specific regulatory mechanisms and their implications on immunotherapy remain unclear. Thus, it is worth unraveling the characteristics of TME and its impact on antitumor immunity, in the hope of devising novel strategies to reinforce immunotherapeutic effects on SCLC. In this review, we firstly elaborate on the immune landscape of SCLC and the formation of three remarkable characteristics in TME, as well as the interaction among them. Next, we summarize the latest findings regarding the impacts of adverse TME on immune cells and its targeted therapy in SCLC. Finally, we discuss the ongoing trials in combination therapy and potential directions of SCLC therapy. Collectively, the findings combined here are expected to aid the design of trials for combining immunotherapy with therapy targeting the TME of SCLC.

Delicaflavone Represses Lung Cancer Growth by Activating Antitumor Immune Response through N6-Methyladenosine Transferases and Oxidative Stress

Our previous studies have shown that delicaflavone (DLL), a biocomponent extracted from Selaginella doederleinii Hieron, has antitumor activity. However, the role of DLL in the antitumor immune response is unknown. In this study, we tested the potential roles of DLL in antitumor immune response. An animal tumor model with Lewis lung cancer cell line (3LL) in C57BL/6 mice was established to determine whether DLL induced the tumor-bearing host's antitumor immune response. m6A-MeRIP-qPCR, western blot, and flow cytometry were performed to explore the underlying mechanisms. DLL inhibited the proliferation of 3LL lung cancer cells in vitro and in vivo and induced tumor cell oxidative stress. DLL significantly inhibited tumor growth in immunocompetent mice compared with nude mice. DLL treatment significantly increased Th1 cytokine production and CD8+ T cell infiltration into tumor tissues in tumor-bearing mice. DLL-mediated antitumor immune effects were reversed by overexpression of the N6-methyladenosine (m6A) transferase Mettl3/Mettl14. Mechanistically, DLL upregulated the expression of Stat1 and Irf1 and the secretion of cytokines by inhibiting Mettl3 and Mettl14 in lung cancer cells. In conclusion, DLL inhibited lung cancer cell growth by suppressing Mettl3/Mettl14 to activate antitumor immunity. These findings provided an opportunity to enhance lung cancer immunotherapy.