The regulation of oxidative stress is an important factor in both tumour development and responses to anticancer therapies. Many signalling pathways that are linked to tumorigenesis can also regulate ...the metabolism of reactive oxygen species (ROS) through direct or indirect mechanisms. High ROS levels are generally detrimental to cells, and the redox status of cancer cells usually differs from that of normal cells. Because of metabolic and signalling aberrations, cancer cells exhibit elevated ROS levels. The observation that this is balanced by an increased antioxidant capacity suggests that high ROS levels may constitute a barrier to tumorigenesis. However, ROS can also promote tumour formation by inducing DNA mutations and pro-oncogenic signalling pathways. These contradictory effects have important implications for potential anticancer strategies that aim to modulate levels of ROS. In this Review, we address the controversial role of ROS in tumour development and in responses to anticancer therapies, and elaborate on the idea that targeting the antioxidant capacity of tumour cells can have a positive therapeutic impact.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Heterozygous mutations in catalytic arginine residues of isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) are common in glioma, acute myeloid leukemia, chondrosarcoma, cholangiocarcinoma, and ...angioimmunoblastic T-cell lymphoma. The mutant enzymes acquire a neomorphic activity that converts α-ketoglutarate (α-KG) to D-2-hydroxyglutarate (D2HG), a rare metabolite. In cells and tissues expressing mutant IDH, D2HG concentrations are highly elevated. D2HG may act as an "oncometabolite" by inhibiting a class of α-KG-dependent enzymes involved in epigenetic regulation, collagen synthesis, and cell signaling. Knock-in mouse models of IDH1 mutations have shed light on these mechanisms and will provide valuable animal models for further investigation.
The cell cycle is an evolutionarily conserved process necessary for mammalian cell growth and development. Because cell-cycle aberrations are a hallmark of cancer, this process has been the target of ...anti-cancer therapeutics for decades. However, despite numerous clinical trials, cell-cycle-targeting agents have generally failed in the clinic. This review briefly examines past cell-cycle-targeted therapeutics and outlines how experience with these agents has provided valuable insight to refine and improve anti-mitotic strategies. An overview of emerging anti-mitotic approaches with promising pre-clinical results is provided, and the concept of exploiting the genomic instability of tumor cells through therapeutic inhibition of mitotic checkpoints is discussed. We believe this strategy has a high likelihood of success given its potential to enhance therapeutic index by targeting tumor-specific vulnerabilities. This reasoning stimulated our development of novel inhibitors targeting the critical regulators of genomic stability and the mitotic checkpoint: AURKA, PLK4, and Mps1/TTK.
Dominguez-Brauer et al. review the therapeutic potential of exploiting the genomic instability of tumor cells by inhibiting mitotic checkpoints as a strategy to selectively target tumor-specific vulnerabilities.
Controversy over the role of antioxidants in cancer has persisted for decades. Here, we demonstrate that synthesis of the antioxidant glutathione (GSH), driven by GCLM, is required for cancer ...initiation. Genetic loss of Gclm prevents a tumor’s ability to drive malignant transformation. Intriguingly, these findings can be replicated using an inhibitor of GSH synthesis, but only if delivered prior to cancer onset, suggesting that at later stages of tumor progression GSH becomes dispensable potentially due to compensation from alternative antioxidant pathways. Remarkably, combined inhibition of GSH and thioredoxin antioxidant pathways leads to a synergistic cancer cell death in vitro and in vivo, demonstrating the importance of these two antioxidants to tumor progression and as potential targets for therapeutic intervention.
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•The GSH antioxidant pathway is required for cancer initiation•After cancer initiation, GSH is dispensable due to alternative antioxidant pathways•The TXN antioxidant pathway is upregulated in tumors•Inhibition of both GSH and TXN pathways causes synergistic cancer cell death
Harris et al. show that the antioxidant glutathione (GSH) is required for cancer initiation but not for established tumors partly due to upregulation of the thioredoxin (TXN) antioxidant pathway in the latter. Consequently, blocking both GSH and TXN pathways synergistically inhibits tumor growth.
The p53 protein is activated by stress signals and exhibits both protective and death-promoting functions that are considered important for its tumor suppressor function. Emerging evidence points ...toward an additional role for p53 in metabolism. Here, we identify Lpin1 as a p53-responsive gene that is induced in response to DNA damage and glucose deprivation. Lpin1 is essential for adipocyte development and fat metabolism, and mutation in this gene is responsible for the lypodystrophy phenotype in fld mice. We show that p53 and Lpin1 regulate fatty acid oxidation in mouse C2C12 myoblasts. p53 phosphorylation on Ser18 in response to low glucose is ROS and ATM dependent. Lpin1 expression in response to nutritional stress is controlled through the ROS-ATM-p53 pathway and is conserved in human cells. Lpin1 provides a critical link between p53 and metabolism that may be an important component in mediating the tumor suppressor function of p53.
► p53 regulates lipid metabolism through lipin-1 expression ► ATM phosphorylates p53 under conditions of low glucose ► ROS levels increase in response to low glucose ► A ROS-ATM-p53 pathway controls Lpin1 in response to nutrient stress
Genomic sequencing studies of breast and other cancers have identified patterns of mutations that have been attributed to the endogenous mutator activity of APOBEC3B (A3B), a member of the AID/APOBEC ...family of cytidine deaminases. A3B gene expression is increased in many cancers, but its upstream drivers remain undefined. Furthermore, there exists a common germ-line deletion polymorphism ( A3B ᵈᵉˡ), which has been associated with a paradoxical increase in breast cancer risk. To examine causes and consequences of A3B expression and its constitutive absence in breast cancer, we analyzed two large clinically annotated genomic datasets The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). We confirmed that A3B expression is associated with aggressive clinicopathologic characteristics and adverse outcomes and show that A3B expression is highly correlated with proliferative features (mitosis and cell cycle-related gene expression) in breast and 15 of 16 other solid tumor types. However, breast cancers arising in homozygous A3B ᵈᵉˡ individuals with A3B absent did not differ in these features, indicating that A3B expression is a reflection rather than a direct cause of increased proliferation. Using gene set enrichment analysis (GSEA), we detected a pattern of immune activation in A3B ᵈᵉˡ breast cancers, which seems to be related to hypermutation arising in A3B ᵈᵉˡ carriers. Together, these results provide an explanation for A3B overexpression and its prognostic effect, giving context to additional study of this mutator as a cancer biomarker or putative drug target. In addition, although immune features of A3B ᵈᵉˡ require additional study, these findings nominate the A3B ᵈᵉˡ polymorphism as a potential predictor for cancer immunotherapy.
Significance Somatic mutagenesis is fundamental to the development and evolution of cancers. APOBEC3B (A3B) is a cellular deaminase, which is overexpressed in cancers and believed to be an important cause of cancer-associated mutations. The factors responsible for A3B up-regulation are unknown. Interestingly, a germ-line deletion polymorphism exists, such that a significant proportion of the global population does not express A3B protein. Using large human cancer datasets, we show that A3B expression is strongly associated with cellular proliferation. Furthermore, we identify a pattern of immune activation related to hypermutation in tumors arising in A3B deletion carriers suggesting that these patients could respond differently to immune-directed therapies. These results provide important context for the ongoing study of A3B as a therapeutic target or biomarker.
Carcinogen exposure has been associated with enhanced cancer immunogenicity that is often attributed to neoantigen generation. However, the broader, neoantigen-independent impact of carcinogens on ...immune responses to cancer cells remains underexplored. In this issue of the JCI, Huang et al. uncover a mechanism wherein carcinogen-treated cancer cells exhibit an inability to establish an immunosuppressive tumor microenvironment (TME) due to reduced M-CSF expression. Intriguingly, the so-called carcinogen-induced tumor-associated macrophages (TAMs) within this TME exhibited anti-tumor properties instead of the conventional immunosuppressive phenotype. This phenomenon extended to human lung cancers, as evidenced by TAM reprogramming in smokers versus nonsmokers. This study substantially advances our understanding of carcinogen-mediated effects on cancer immunogenicity, potentially redirecting approaches to cancer immunotherapy.
Gastric cancer displays marked molecular heterogeneity with aggressive behavior and treatment resistance. Therefore, good in vitro models that encompass unique subtypes are urgently needed for ...precision medicine development. Here, we have established a primary gastric cancer organoid (GCO) biobank that comprises normal, dysplastic, cancer, and lymph node metastases (n = 63) from 34 patients, including detailed whole-exome and transcriptome analysis. The cohort encompasses most known molecular subtypes (including EBV, MSI, intestinal/CIN, and diffuse/GS, with CLDN18-ARHGAP6 or CTNND1-ARHGAP26 fusions or RHOA mutations), capturing regional heterogeneity and subclonal architecture, while their morphology, transcriptome, and genomic profiles remain closely similar to in vivo tumors, even after long-term culture. Large-scale drug screening revealed sensitivity to unexpected drugs that were recently approved or in clinical trials, including Napabucasin, Abemaciclib, and the ATR inhibitor VE-822. Overall, this new GCO biobank, with linked genomic data, provides a useful resource for studying both cancer cell biology and precision cancer therapy.
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•Living biobank includes 17 normal and 46 gastric cancer organoid lines•Organoid biobank encompasses most of the known molecular subtypes of gastric cancer•Organoids recapitulate the genomic and transcriptomic features of original tumors•High-throughput screen revealed potential target drugs for personalized therapy
Leung and colleagues established a biobank of patient-derived gastric cancer organoids that encompasses a diverse array of subtypes and maintained long-term similarity to the original tumors. They used the organoids to perform large-scale drug screening that identified potential target drugs and could guide patient drug selection.
Despite development of new antiviral drugs, viral infections are still a major health problem. The most potent antiviral defense mechanism is the innate production of type I interferon (IFN-I), which ...not only limits virus replication but also promotes antiviral T cell immunity through mechanisms, which remain insufficiently studied. Using the murine lymphocytic choriomeningitis virus model system, we show here that IFN-I signaling on T cells prevented their rapid elimination in vivo. Microarray analyses uncovered that IFN-I triggered the expression of selected inhibitory NK-cell-receptor ligands. Consequently, T cell immunity of IFN-I receptor (IFNAR)-deficient T cells could be restored by NK cell depletion or in NK-cell-deficient hosts (Nfil3–/–). The elimination of Ifnar1–/– T cells was dependent on NK-cell-mediated perforin expression. In summary, we identified IFN-I as a key player regulating the protection of T cells against regulatory NK cell function.
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•Ifnar1–/– T cells proliferate in vitro, but not in vivo, suggesting cell interaction•Microarray analyses identify MHC molecules as being regulated by type I interferons•NK cell deficiency rescues expansion and function of IFN-I unresponsive T cells•NK-cell-mediated killing of activated Ifnar1–/– CD8+ T cells depends on perforin
Type I interferons (IFN-I) are important for promoting antiviral T cell immunity, but the mechanisms behind IFN-I action have been unclear. Xu et al. show that IFN-I protects antiviral T cells from regulatory cytotoxic effects of natural killer cells and promotes their expansion and antiviral effector functions.
Tumour necrosis factor (TNF) is a pro-inflammatory cytokine that has important roles in mammalian immunity and cellular homeostasis. Deregulation of TNF receptor (TNFR) signalling is associated with ...many inflammatory disorders, including various types of arthritis and inflammatory bowel disease, and targeting TNF has been an effective therapeutic strategy in these diseases. This Review focuses on the recent advances that have been made in understanding TNFR signalling and the consequences of its deregulation for cellular survival, apoptosis and regulated necrosis. We discuss how TNF-induced survival signals are distinguished from those that lead to cell death. Finally, we provide a brief overview of the role of TNF in inflammatory and autoimmune diseases, and we discuss up-to-date and future treatment strategies for these disorders.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UILJ, UKNU, UL, UM, UPUK
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