Targeting ABL1-mediated oxidative stress adaptation in fumarate hydratase-deficient cancer

Complete response to fifth-line anti-PD-1 rechallenge in fumarate hydratase-mutated papillary renal cell carcinoma

Fumarate hydratase (FH) mutated papillary renal cell carcinoma is an aggressive variant of kidney cancer that poorly responds to conventional targeted therapies and immunotherapy. Here, we present the 10-year follow-up of a heavily pre-treated patient with several lines of therapy, achieving a remarkable complete response to anti-PD-1 rechallenge. In addition, we highlight a common immune-related adverse event of anti-PD-1, eosinophilia, as a possible biomarker of response and using TCGA data analysis, provide proof-of-concept for tumor expression of the eosinophil-related gene SIGLEC8, as a promising powerful predictor of prognosis for papillary renal cell carcinoma patients.

ABL1-mediated phosphorylation promotes FOXM1-related tumorigenicity by Increasing FOXM1 stability

The transcription factor FOXM1, which plays critical roles in cell cycle progression and tumorigenesis, is highly expressed in rapidly proliferating cells and various tumor tissues, and high FOXM1 expression is related to a poor prognosis. However, the mechanism responsible for FOXM1 dysregulation is not fully understood. Here, we show that ABL1, a nonreceptor tyrosine kinase, contributes to the high expression of FOXM1 and FOXM1-dependent tumor development. Mechanistically, ABL1 directly binds FOXM1 and mediates FOXM1 phosphorylation at multiple tyrosine (Y) residues. Among these phospho-Y sites, pY575 is indispensable for FOXM1 stability as phosphorylation at this site protects FOXM1 from ubiquitin-proteasomal degradation. The interaction of FOXM1 with CDH1, a coactivator of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), which is responsible for FOXM1 degradation, is significantly inhibited by Y575 phosphorylation. The phospho-deficient FOXM1(Y575F) mutant exhibited increased ubiquitination, a shortened half-life, and consequently a substantially decreased abundance. Compared to wild-type cells, a homozygous Cr-Y575F cell line expressing endogenous FOXM1(Y575F) that was generated by CRISPR/Cas9 showed obviously delayed mitosis progression, impeded colony formation and inhibited xenotransplanted tumor growth. Overall, our study demonstrates that ABL1 kinase is involved in high FOXM1 expression, providing clear evidence that ABL1 may act as a therapeutic target for the treatment of tumors with high FOXM1 expression.

Luteolin ameliorates hyperuricemic nephropathy by activating urate excretion and Nrf2/HO-1/NQO1 antioxidant pathways in mice

Luteolin is a natural flavonoid, which exists in many plants, including onions, broccoli, carrots, peppers, celery, olive oil, and mint. Luteolin is a dietary flavonoid with potent uric acid-lowering and antioxidant bioactivities. To date, the mechanism by which luteolin alleviates hyperuricemia nephropathy (HN) still needs to be better defined. This study aims to evaluate the therapeutic efficacy of luteolin in a preclinical mouse model and in vitro. Luteolin was administered in the HN mice induced by the combination of potassium oxonate and hypoxanthine to evaluate the potential renoprotective effects in vivo. The NRK-52E cells were stimulated with adenosine for in vitro evaluation. Hematoxylin and eosin staining, biochemical analysis, immunoblotting, immunofluorescence, and immunohistochemistry were performed for the histopathologic and mechanistic investigations. The results suggest that luteolin attenuated tubular dilation and epithelial atrophy in the renal tissue of HN mice. Further, luteolin improved biochemical indicators concerning renal functions and oxidative stress in vivo. Mechanistically, luteolin reduced the renal expressions of KIM-1 and caspase-3. Luteolin activated renal SIRT1/6 cascade and its downstream Nrf2-mediated antioxidant pathway. Furthermore, luteolin elevated the renal expressions of ATP-binding cassette subfamily G isoform 2 protein (ABCG2) and organic anion/cation transporters. In addition, livers of luteolin-treated HN mice exhibited robust inhibition of xanthine oxidase. Together, our study shows that luteolin alleviates renal injury in the HN mice by activating urate excretion and Nrf2/HO-1/NQO1 antioxidant pathways and inhibiting liver xanthine oxidase activity. Thus, luteolin may be a potential agent for the treatment of HN.

Ferroptosis: a promising target for fumarate hydratase-deficient tumor therapeutics literature review

Background and Objective

This review aims to investigate the ferroptosis mechanism of fumarate hydratase (FH)-related tumors for the purpose of possible treatment of tumors. Ferroptosis is an iron (Fe)-dependent form of regulated cell death caused by lipid peroxidation on the cell membrane. Studies have implicated FH in tumorigenesis. As mutations in the FH gene alter cellular metabolism and increase tumorigenesis risk, particularly in the kidneys. As most tumor cells require higher amounts of ferrous ions (Fe2+) than normal cells, they are more susceptible to ferroptosis. Recent studies have indicated that ferroptosis is inhibited the pathogenesis and progression of FH-deficient tumors by regulating lipid and iron metabolism, glutathione-glutathione peroxidase 4 (GSH-GPX4), nuclear factor-erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathways. While the Fe2+ content is significantly lower in FH-deficient tumor cells, than that in normal cells. It is promising to promote ferroptosis by increasing the concentration of Fe2+ in cells to achieve the purpose of tumor treatment.

Methods

In this study, we searched for relevant articles on ferroptosis and FH-deficient tumors using PubMed database.

Key Content and Findings

FH is a tumor suppressor. A number of basic studies have shown that the loss of FH plays an important role in hereditary leiomyomas and tumors such as renal cell carcinoma, ovarian cancer, and other tumors. This type of tumor cells can through induce ferroptosis, inhibit proliferation, migration and invasion of tumor cells, increase the sensitivity of tumor cells to chemotherapy, and reverse the drug resistance through various molecular mechanisms. At present, the research on ferroptosis in FH-related tumors is still in the basic experimental stage.

Conclusions

This article reviews the anti-tumor effects and mechanisms of FH and ferroptosis, in order to further explore the medical value of ferroptosis in FH-related tumor therapy.

Impact of Abl2/Arg deficiency on anxiety and depressive behaviors in mice

Abl2/Arg (ABL-related gene) is a member of the Abelson family of nonreceptor tyrosine kinases, known for its role in tumor progression, metastasis, tissue injury responses, inflammation, neural degeneration, and other diseases. In this study, we developed Abl2/Arg knockout (abl2-/-) mice to explore its impact on sensory/motor functions and emotion-related behaviors. Our findings show that abl2-/- mice exhibit normal growth and phenotypic characteristics, closely resembling their wild-type (WT) counterparts. Behavioral tests, including the elevated plus maze, marble-burying behavior test, and open field test, indicated pronounced anxiety-like behaviors in abl2-/- mice compared to WT mice. Furthermore, in the tail suspension test, abl2-/- mice showed a significant decrease in mobility time, suggesting depressive-like behavior. Conversely, in the Y-maze and cliff avoidance reaction tests, no notable differences were observed between abl2-/- and WT mice, suggesting the absence of working memory deficits and impulsivity in abl2-/- mice. Proteomic analysis of the hippocampus in abl2-/- mice highlighted significant alterations in proteins related to anxiety and depression, especially those associated with the GABAergic synapse in inhibitory neurotransmission. The expression of Gabbr2 was significantly reduced in the hippocampus of abl2-/- compared to WT mice, and intraperitoneal treatment of GABA receptor agonist Gaboxadol normalized anxiety/depression-related behaviors of abl2-/- mice. These findings underscore the potential role of Abl2/Arg in influencing anxiety and depressive-like behaviors, thereby contributing valuable insights into its broader physiological and pathological functions.

Oroxylin A ameliorates ultraviolet radiation-induced premature skin aging by regulating oxidative stress via the Sirt1 pathway

Skin is susceptible to premature aging in response to ultraviolet (UV) radiation-induced oxidative stress, which can ultimately result in aberrant aging or age-related disorders. Accordingly, strategies that can be adopted to mitigate oxidative stress may contribute to protecting skin from induced aging-related damage, thereby offering promising approaches for the treatment of skin diseases and disorders. In this regard, oroxylin A (OA), a natural flavonoid isolated from certain plants used in traditional Chinese medicine, is considered to have notable antioxidant, anti-inflammatory, and anti-apoptotic properties, and is often used to treat certain inflammatory diseases. To date, however, there has been comparatively little research on the effects of OA with respect skin aging. In this study, we utilized UV radiation-induced mouse and cellular models of aging to assess the efficacy of OA in protecting against skin aging. Subsequently, to elucidate the potential mechanisms underlying the protective effect of OA on skin aging, we performed molecular docking analysis to investigate the involvement of the anti-aging gene Sirt1, which was further confirmed on the basis of Sirt1 gene silencing. We accordingly demonstrated that by promoting an increase in the expression of Sirt1, OA can contribute to suppressing UV-induced skin photo-aging in cells/mice by reducing oxidative stress. Furthermore, we established that by activating Sirt1, OA can also promote the dissociation of Nrf2 from Keap1 and its subsequent nuclear translocation. Collectively, our findings in this study reveal OA to be an effective natural compound that can be administered to delay the aging of skin triggered by UV, both in vivo and in vitro, by binding to Sirt1 to promote the deacetylation and nuclear translocation of Nrf2, thereby contributing to a reduction in oxidative stress. These findings may this provide a therapeutic target for the prevention of skin aging or aging-induced skin diseases.

PDGFRβ Signaling Cooperates with β-Catenin to Modulate c-Abl and Biologic Behavior of Desmoid-Type Fibromatosis

PURPOSE

This study sought to identify β-catenin targets that regulate desmoid oncogenesis and determine whether external signaling pathways, particularly those inhibited by sorafenib (e.g., PDGFRβ), affect these targets to alter natural history or treatment response in patients.

EXPERIMENTAL DESIGN

In vitro experiments utilized primary desmoid cell lines to examine regulation of β-catenin targets. Relevance of results was assessed in vivo using Alliance trial A091105 correlative biopsies.

RESULTS

CTNNB1 knockdown inhibited hypoxia-regulated gene expression in vitro and reduced levels of HIF1α protein. ChIP-seq identified ABL1 as a β-catenin transcriptional target that modulated HIF1α and desmoid cell proliferation. Abrogation of either CTNNB1 or HIF1A inhibited desmoid cell-induced VEGFR2 phosphorylation and tube formation in endothelial cell co-cultures. Sorafenib inhibited this activity directly but also reduced HIF1α protein expression and c-Abl activity while inhibiting PDGFRβ signaling in desmoid cells. Conversely, c-Abl activity and desmoid cell proliferation were positively regulated by PDGF-BB. Reduction in PDGFRβ and c-Abl phosphorylation was commonly observed in biopsy samples from patients after treatment with sorafenib; markers of PDGFRβ/c-Abl pathway activation in baseline samples were associated with tumor progression in patients on the placebo arm and response to sorafenib in patients receiving treatment.

CONCLUSIONS

The β-catenin transcriptional target ABL1 is necessary for proliferation and maintenance of HIF1α in desmoid cells. Regulation of c-Abl activity by PDGF signaling and targeted therapies modulates desmoid cell proliferation, thereby suggesting a reason for variable biologic behavior between tumors, a mechanism for sorafenib activity in desmoids, and markers predictive of outcome in patients.

Natural products for gastric carcinoma prevention and treatment: Focus on their antioxidant stress actions in the Correa's cascade

BACKGROUND

Correa's cascade is a pathological process beginning from gastritis to gastric precancerous lesions, and finally to gastric carcinoma (GC). While the pathogenesis of GC remains unclear, oxidative stress plays a prominent role throughout the entire Correa's cascade process. Studies have shown that some natural products (NPs) could halt and even reverse the development of the Correa's cascade by targeting oxidative stress.

METHODS

To review the effects and mechanism by which NPs inhibit the Correa's cascade through targeting oxidative stress, data were collected from PubMed, Embase, Web of Science, ScienceDirect, and China National Knowledge Infrastructure databases from initial establishment to April 2023. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as terpenoid, polyphenols and alkaloids, exert multistep antioxidant stress effects on the Correa's cascade. These effects include preventing gastric mucosal inflammation (stage 1), reversing gastric precancerous lesions (stage 2), and inhibiting gastric carcinoma (stage 3). NPs can directly impact the conversion of gastritis to GC by targeting oxidative stress and modulating signaling pathways involving IL-8, Nrf2, TNF-α, NF-κB, and ROS/MAPK. Among which polyphenols have been studied more and are of high research value.

CONCLUSIONS

NPs display a beneficial multi-step action on the Correa's cascade, and have potential value for clinical application in the prevention and treatment of gastric cancer by regulating the level of oxidative stress.

Cryptic splice mutation in the fumarate hydratase gene in patients with clinical manifestations of Hereditary Leiomyomatosis and Renal Cell Cancer

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant condition characterized by the development of cutaneous and uterine leiomyomas and risk for development of an aggressive form of papillary renal cell cancer. HLRCC is caused by germline inactivating pathogenic variants in the fumarate hydratase (FH) gene, which encodes the enzyme that catalyzes the interconversion of fumarate and L-malate. We utilized enzyme and protein mobility assays to evaluate the FH enzyme in a cohort of patients who showed clinical manifestations of HLRCC but were negative for known pathogenic FH gene variants. FH enzyme activity and protein levels were decreased by 50% or greater in three family members, despite normal FH mRNA expression levels as measured by quantitative PCR. Direct Nanopore RNA sequencing demonstrated 57 base pairs of retained intron sequence between exons 9 and 10 of polyadenylated FH mRNA in these patients, resulting in a truncated FH protein. Genomic sequencing revealed a heterozygous intronic alteration of the FH gene (chr1: 241498239 T/C) resulting in formation of a splice acceptor site near a polypyrimidine tract, and a uterine fibroid obtained from a patient showed loss of heterozygosity at this site. The same intronic FH variant was identified in an unrelated patient who also showed a clinical phenotype of HLRCC. These data demonstrate that careful clinical assessment as well as biochemical characterization of FH enzyme activity, protein expression, direct RNA sequencing, and genomic DNA sequencing of patient-derived cells can identify pathogenic variants outside of the protein coding regions of the FH gene.

Fumarate hydratase (FH) and cancer: a paradigm of oncometabolism

Fumarate hydratase (FH) is an enzyme of the Tricarboxylic Acid (TCA) cycle whose mutations lead to hereditary and sporadic forms of cancer. Although more than twenty years have passed since its discovery as the leading cause of the cancer syndrome Hereditary leiomyomatosis and Renal Cell Carcinoma (HLRCC), it is still unclear how the loss of FH causes cancer in a tissue-specific manner and with such aggressive behaviour. It has been shown that FH loss, via the accumulation of FH substrate fumarate, activates a series of oncogenic cascades whose contribution to transformation is still under investigation. In this review, we will summarise these recent findings in an integrated fashion and put forward the case that understanding the biology of FH and how its mutations promote transformation will be vital to establish novel paradigms of oncometabolism.

A high-throughput Gaussia luciferase reporter assay for screening potential gasdermin E activators against pancreatic cancer

It is discovered that activated caspase-3 tends to induce apoptosis in gasdermin E (GSDME)-deficient cells, but pyroptosis in GSDME-sufficient cells. The high GSDME expression and apoptosis resistance of pancreatic ductal adenocarcinoma (PDAC) cells shed light on another attractive strategy for PDAC treatment by promoting pyroptosis. Here we report a hGLuc-hGSDME-PCA system for high-throughput screening of potential GSDME activators against PDAC. This screening system neatly quantifies the oligomerization of GSDME-N to characterize whether pyroptosis occurs under the stimulation of chemotherapy drugs. Based on this system, ponatinib and perifosine are screened out from the FDA-approved anti-cancer drug library containing 106 compounds. Concretely, they exhibit the most potent luminescent activity and cause drastic pyroptosis in PDAC cells. Further, we demonstrate that perifosine suppresses pancreatic cancer by promoting pyroptosis via caspase-3/GSDME pathway both in vitro and in vivo. Collectively, this study reveals the great significance of hGLuc-hGSDME-PCA in identifying compounds triggering GSDME-dependent pyroptosis and developing promising therapeutic agents for PDAC.

eIF3d controls the persistent integrated stress response

Cells respond to intrinsic and extrinsic stresses by reducing global protein synthesis and activating gene programs necessary for survival. Here, we show that the integrated stress response (ISR) is driven by the non-canonical cap-binding protein eIF3d that acts as a critical effector to control core stress response orchestrators, the translation factor eIF2α and the transcription factor ATF4. We find that during persistent stress, eIF3d activates the translation of the kinase GCN2, inducing eIF2α phosphorylation and inhibiting general protein synthesis. In parallel, eIF3d upregulates the m6A demethylase ALKBH5 to drive 5' UTR-specific demethylation of stress response genes, including ATF4. Ultimately, this cascade converges on ATF4 expression by increasing mRNA engagement of translation machinery and enhancing ribosome bypass of upstream open reading frames (uORFs). Our results reveal that eIF3d acts in a life-or-death decision point during chronic stress and uncover a synergistic signaling mechanism in which translational cascades complement transcriptional amplification to control essential cellular processes.

Identification of prognostic and therapeutic biomarkers in type 2 papillary renal cell carcinoma

BACKGROUND

Papillary renal cell carcinoma (PRCC) can be divided into type 1 (PRCC1) and type 2 (PRCC2) and PRCC2 share a more invasive phenotype and worse prognosis. This study aims to identify potential prognostic and therapeutic biomarkers in PRCC2.

METHODS

A cohort from The Cancer Genome Atlas and two datasets from Gene Expression Omnibus were examined. Common differentially expressed genes (DEGs) were screened and potential biomarkers were explored by using Kaplan-Meier method and cox regression analysis. Functional enrichment analysis was utilized to evaluate the potential biological functions. Tumor infiltrating immune cells were estimated by CIBERSORT algorithm. Ninety-two PRCC2 samples from Fudan University Shanghai Cancer Center were obtained, and immunostaining was performed to validate prognostic and therapeutic significance of the potential biomarker.

RESULTS

PRCC2 has worse overall survival and shares distinct molecular characteristics from PRCC1. There was significant higher expression level of Targeting protein for Xklp2 (TPX2) in PRCC2 compared with normal tissues. Higher expression level of TPX2 was significantly associated with worse overall survival in PRCC2 and kinesin family genes expression were found significantly elevated in high risk PRCC2. Abundance of tumor infiltrating M1 macrophage was significantly higher in PRCC2 and it was also associated with worse overall survival. In the FUSCC cohort, higher TPX2 expression was significantly correlated with worse overall and progression-free survival. Retrospective analysis indicated that mTOR inhibitor (everolimus) had greater efficacy in the high-risk group than in the low-risk group (overall response rate: 28.6% vs. 16.7%) and that everolimus had greater efficacy than sunitinib in the high-risk group (overall response rate: 28.6% vs. 20%).

CONCLUSIONS

TPX2 was a prognostic and therapeutic biomarker in PRCC2. Higher abundance of tumor infiltrating M1 macrophage was significantly associated with worse overall survival in PRCC2. mTOR inhibitors may have good efficacy in patients with high-risk PRCC2.

Special issue "The advance of solid tumor research in China": Multi-omics analysis based on 1311 clear cell renal cell carcinoma samples identifies a glycolysis signature associated with prognosis and treatment response

In clear cell renal cell carcinoma (ccRCC), glycolysis is enhanced mainly because of the increased expression of key enzymes in glycolysis. Hence, the discovery of new molecular biomarkers for glycolysis may help guide and establish a precise system of diagnosis and treatment for ccRCC. Expression profiles of 1079 tumor samples of ccRCC patients (including 311 patients treated with everolimus or nivolumab) were downloaded from public databases. Proteomic profiles of 232 ccRCC samples were obtained from Fudan University Shanghai Cancer Center (FUSCC). Biological changes, tumor microenvironment and prognostic differences were explored between samples with various glycolysis characteristics. There were significant differences in CD8⁺ effector T cells, epithelial-to-mesenchymal transition and pan-fibroblast TGFb between the Low and High glyScore groups. The tumor mutation burden of the Low glyScore group was lower than that of the High glyScore group. And higher glyScore was significantly associated with worse overall survival (OS) in 768 ccRCC patients (P < .0001). External validation in FUSCC cohort also indicated that glyScore was of strong ability for predicting OS (P < .05). GlyScore may serve as a biomarker for predicting everolimus response in ccRCC patients due to its significant associations with progression-free survival (PFS). And glyScore may also predict overall survival in patients treated with nivolumab. We calculated the glyScore in ccRCC and the defined glyScore was of strong ability for predicting OS. In addition, glyScore may also serve as a biomarker for predicting PFS in patients treated with everolimus and could predict OS in patients treated with nivolumab.

The oncogene ABL1 regulates the inflammatory response of innate immunity via mediating TRAF6 ubiquitination

The oncogene ABL1 plays an important role in various cancers, while its roles remain unclear in pneumonia. This study aims to investigate the roles of ABL1 in pneumonia and the underlying mechanisms. RNA sequencing was used to determine the expressions of multiple kinases in the PBMCs. A series of overexpression and knockout cell lines were constructed. Besides, an intranasal lung infection mouse model was pre-treated with asciminb. ELISAs and qPCR were used to determine the levels of target genes. In addition, STRING Interaction Network and Immunoblotting assays were used to determine the interaction between target proteins. An elevation in ABL1 was observed in the infant with Ecoli pneumonia. ABL1 was positively correlated to the levels of inflammatory cytokines and the activation of the NF-kB pathways. In vivo data demonstrated that the inhibition of ABL1 suppressed the inflammatory cytokines, reduced the lung bacterial burden, and ameliorated the lung injury score. ABL1 inhibited the phosphorylation of IκBα and p38 and regulated the ubiquitination of TRAF6. ABL1 regulates the inflammatory response in pneumonia in part by the regulation of MAPK and NF-κB pathways and TRAF6 ubiquitination.

Comprehensive transcriptomic and co-expression analysis of ABL1 gene and molecularly targeted drugs in hepatocellular carcinoma based on multi-database mining

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide. Consequently, it is essential to identify biomarkers for treatment response and the prognosis prediction. We investigated whether ABL1 can function as a biomarker or a drug target for HCC. We assessed the ABL1 expression, genetic alterations and patients' survival from LinkedOmics, GEO, TCGA and Human Protein Atlas. We analyzed PPI, GO and KEGG pathways. GSEA was analyzed for functional comparison. The current drugs targeting ABL1 were statistically analyzed using DRUGSURV and DGIdb database. We found ABL1 is overexpressed in HCC and its higher expression reduces survival probability. Genetic changes of ABL1 are not frequent. We screened out 25 differentially expressed genes correlated with ABL1. The top functions of ABL1 are biological regulation, metabolic process, protein-containing, and protein binding. KEGG pathways showed that ABL1 and correlated with ABL1 significantly genes markedly enriched in the ErbB signaling pathway, and pathways in cancer. We counted the existing drugs targeting ABL1, which indicates that inhibiting ABL1 expression may improve the survival probability of HCC. In conclusion, ABL1 plays a crucial role in the development and progression of this cancerization and is a potential drug target.

Metabolic Adaptation-Mediated Cancer Survival and Progression in Oxidative Stress

Undue elevation of ROS levels commonly occurs during cancer evolution as a result of various antitumor therapeutics and/or endogenous immune response. Overwhelming ROS levels induced cancer cell death through the dysregulation of ROS-sensitive glycolytic enzymes, leading to the catastrophic depression of glycolysis and oxidative phosphorylation (OXPHOS), which are critical for cancer survival and progression. However, cancer cells also adapt to such catastrophic oxidative and metabolic stresses by metabolic reprograming, resulting in cancer residuality, progression, and relapse. This adaptation is highly dependent on NADPH and GSH syntheses for ROS scavenging and the upregulation of lipolysis and glutaminolysis, which fuel tricarboxylic acid cycle-coupled OXPHOS and biosynthesis. The underlying mechanism remains poorly understood, thus presenting a promising field with opportunities to manipulate metabolic adaptations for cancer prevention and therapy. In this review, we provide a summary of the mechanisms of metabolic regulation in the adaptation of cancer cells to oxidative stress and the current understanding of its regulatory role in cancer survival and progression.

c-Abl controls BCR signaling and B cell differentiation by promoting B cell metabolism

As a non-receptor tyrosine kinase, c-Abl was first studied in chronic myelogenous leukemia, and its role in lymphocytes has been well characterized. c-Abl is involved in B cell development and CD19 associated B cell antigen receptor (BCR) signaling. Although c-Abl regulates different metabolic pathways, the role of c-Abl is still unknown in B cell metabolism. In this study, B cell specific c-Abl knockout (KO) mice (Mb1^Cre+/- c-Abl^fl/fl ) were used to investigate how c-Abl regulates B cell metabolism and BCR signaling. We found that the levels of activation positive BCR signaling proximal molecules, phosphorylated spleen tyrosine kinase (pSYK) and phosphorylated Bruton tyrosine kinase (pBTK), were decreased, while the level of key negative regulator, phosphorylated SH2-containing inositol phosphatase (pSHIP1), was increased in Mb1^Cre+/- c-Abl^fl/fl mice. Furthermore, we found c-Abl deficiency weakened the B cell spreading, formation of BCR signalosomes, and the polymerization of actin during BCR activation, and also impaired the differentiation of germinal center (GC) B cells both in quiescent condition and after immunization. Moreover, B cell mitochondrial respiration and the expression of B cell metabolism regulating molecules were downregulated in c-Abl deficiency mice. Overall, c-Abl, which involved in actin remodeling and B cell metabolism, positively regulates BCR signaling and promotes GC differentiation. This article is protected by copyright. All rights reserved.

Hyperpolarized 13C Magnetic Resonance Imaging as a Tool for Imaging Tissue Redox State, Oxidative Stress, Inflammation, and Cellular Metabolism

Significance: Magnetic resonance imaging (MRI) with hyperpolarized (HP) ¹³C-labeled redox-sensitive metabolic tracers can provide noninvasive functional imaging biomarkers, reflecting tissue redox state, oxidative stress, and inflammation, among others. The capability to use endogenous metabolites as ¹³C-enriched imaging tracers without structural modification makes HP ¹³C MRI a promising tool to evaluate redox state in patients with various diseases. Recent Advances: Recent studies have demonstrated the feasibility of in vivo metabolic imaging of ¹³C-labeled tracers polarized by parahydrogen-induced polarization techniques, which offer a cost-effective alternative to the more widely used dissolution dynamic nuclear polarization-based hyperpolarizers. Critical Issues: Although the fluxes of many metabolic pathways reflect the change in tissue redox state, they are not functionally specific. In the present review, we summarize recent challenges in the development of specific ¹³C metabolic tracers for biomarkers of redox state, including that for detecting reactive oxygen species. Future Directions: Applications of HP ¹³C metabolic MRI to evaluate redox state have only just begun to be investigated. The possibility to gain a comprehensive understanding of the correlations between tissue redox potential and metabolism under different pathological conditions by using HP ¹³C MRI is promoting its interest in the clinical arena, along with its noninvasive biomarkers to evaluate the extent of disease and treatment response.

Investigating Pathogenetic Mechanisms of Alzheimer's Disease by Systems Biology Approaches for Drug Discovery

Alzheimer's disease (AD) is the most common cause of dementia, characterized by progressive cognitive decline and neurodegenerative disorder. Abnormal aggregations of intracellular neurofibrillary tangles (NFTs) and unusual accumulations of extracellular amyloid-β (Aβ) peptides are two important pathological features in AD brains. However, in spite of large-scale clinical studies and computational simulations, the molecular mechanisms of AD development and progression are still unclear. In this study, we divided all of the samples into two groups: early stage (Braak score I-III) and later stage (Braak score IV-VI). By big database mining, the candidate genetic and epigenetic networks (GEN) have been constructed. In order to find out the real GENs for two stages of AD, we performed systems identification and system order detection scheme to prune false positives with the help of corresponding microarray data. Applying the principal network projection (PNP) method, core GENs were extracted from real GENs based on the projection values. By the annotation of KEGG pathway, we could obtain core pathways from core GENs and investigate pathogenetic mechanisms for the early and later stage of AD, respectively. Consequently, according to pathogenetic mechanisms, several potential biomarkers are identified as drug targets for multiple-molecule drug design in the treatment of AD.

Development of targeted therapy of NRF2high esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a deadly disease and one of the most aggressive cancers of the gastrointestinal tract. As a master transcription factor regulating the stress response, NRF2 is often mutated and becomes hyperactive, and thus causes chemo-radioresistance and poor survival in human ESCC. There is a great need to develop NRF2 inhibitors for targeted therapy of NRF2high ESCC. In this review, we mainly focus on three aspects, NRF2 inhibitors and their mechanisms of action, screening novel drug targets, and evaluation of NRF2 activity in the esophagus. A research strategy has been proposed to develop NRF2 inhibitors using human ESCC cells and mouse models.

Mitochondrial Tumor Suppressors-The Energetic Enemies of Tumor Progression

Tumor suppressors represent a critical line of defense against tumorigenesis. Their mechanisms of action and the pathways they are involved in provide important insights into cancer progression, vulnerabilities, and treatment options. Although nuclear and cytosolic tumor suppressors have been extensively investigated, relatively little is known about tumor suppressors localized within the mitochondria. However, recent research has begun to uncover the roles of these important proteins in suppressing tumorigenesis. Here, we review this newly developing field and summarize available information on mitochondrial tumor suppressors.

Kidney cancer biomarkers and targets for therapeutics: survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, p53, KRAS and AKT in renal cell carcinoma

The incidence of renal cell carcinoma (RCC) is increasing worldwide with an approximate 20% mortality rate. The challenge in RCC is the therapy-resistance. Cancer resistance to treatment employs multiple mechanisms due to cancer heterogeneity with multiple genetic and epigenetic alterations. These changes include aberrant overexpression of (1) anticancer cell death proteins (e.g., survivin/BIRC5), (2) DNA repair regulators (e.g., ERCC6) and (3) efflux pump proteins (e.g., ABCG2/BCRP); mutations and/or deregulation of key (4) oncogenes (e.g., MDM2, KRAS) and/or (5) tumor suppressor genes (e.g., TP5/p53); and (6) deregulation of redox-sensitive regulators (e.g., HIF, NRF2). Foci of tumor cells that have these genetic alterations and/or deregulation possess survival advantages and are selected for survival during treatment. We will review the significance of survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, TP5/p53, KRAS and AKT in treatment resistance as the potential therapeutic biomarkers and/or targets in RCC in parallel with our analized RCC-relevant TCGA genetic results from each of these gene/protein molecules. We then present our data to show the anticancer drug FL118 modulation of these protein targets and RCC cell/tumor growth. Finally, we include additional data to show a promising FL118 analogue (FL496) for treating the specialized type 2 papillary RCC.

Metabolic reprogramming in renal cancer: Events of a metabolic disease

Recent studies have established that tumors can reprogram the pathways involved in nutrient uptake and metabolism to withstand the altered biosynthetic, bioenergetics and redox requirements of cancer cells. This phenomenon is called metabolic reprogramming, which is promoted by the loss of tumor suppressor genes and activation of oncogenes. Because of alterations and perturbations in multiple metabolic pathways, renal cell carcinoma (RCC) is sometimes termed as a "metabolic disease". The majority of metabolic reprogramming in renal cancer is caused by the inactivation of von Hippel-Lindau (VHL) gene and activation of the Ras-PI3K-AKT-mTOR pathway. Hypoxia-inducible factor (HIF) and Myc are other important players in the metabolic reprogramming of RCC. All types of RCCs are associated with reprogramming of glucose and fatty acid metabolism and the tricarboxylic acid (TCA) cycle. Metabolism of glutamine, tryptophan and arginine is also reprogrammed in renal cancer to favor tumor growth and oncogenesis. Together, understanding these modifications or reprogramming of the metabolic pathways in detail offer ample opportunities for the development of new therapeutic targets and strategies, discovery of biomarkers and identification of effective tumor detection methods.

Characterization of genetically defined sporadic and hereditary type 1 papillary renal cell carcinoma cell lines

Renal cell carcinoma (RCC) is not a single disease but is made up of several different histologically defined subtypes that are associated with distinct genetic alterations which require subtype specific management and treatment. Papillary renal cell carcinoma (pRCC) is the second most common subtype after conventional/clear cell RCC (ccRCC), representing ~20% of cases, and is subcategorized into type 1 and type 2 pRCC. It is important for preclinical studies to have cell lines that accurately represent each specific RCC subtype. This study characterizes seven cell lines derived from both primary and metastatic sites of type 1 pRCC, including the first cell line derived from a hereditary papillary renal carcinoma (HPRC)-associated tumor. Complete or partial gain of chromosome 7 was observed in all cell lines and other common gains of chromosomes 16, 17, or 20 were seen in several cell lines. Activating mutations of MET were present in three cell lines that all demonstrated increased MET phosphorylation in response to HGF and abrogation of MET phosphorylation in response to MET inhibitors. CDKN2A loss due to mutation or gene deletion, associated with poor outcomes in type 1 pRCC patients, was observed in all cell line models. Six cell lines formed tumor xenografts in athymic nude mice and thus provide in vivo models of type 1 pRCC. These type 1 pRCC cell lines provide a comprehensive representation of the genetic alterations associated with pRCC that will give insight into the biology of this disease and be ideal preclinical models for therapeutic studies.

Hereditary Leiomyomatosis and Renal Cell Cancer: Recent Insights Into Mechanisms and Systemic Treatment

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a rare autosomal dominant hereditary cancer syndrome characterized by a predisposition to cutaneous leiomyomas, uterine leiomyomas, and renal cell carcinoma (RCC). It is known to be caused by germline mutations of the fumarate hydratase (FH) gene, which encodes an enzyme component of the citric acid cycle and catalyzes the conversion of fumarate to L-malate. Currently, there is no standardized treatment for HLRCC, which may be due in part to a lack of understanding of the underlying mechanisms. Here, the underlying molecular mechanisms by which the inactivation of FH causes HLRCC are discussed. Additionally, potential therapeutic pharmacological strategies are also summarized to provide new perspectives for the prevention and treatment of HLRCC.

From Metabolism to Genetics and Vice Versa: The Rising Role of Oncometabolites in Cancer Development and Therapy

Over the last decades, the study of cancer metabolism has returned to the forefront of cancer research and challenged the role of genetics in the understanding of cancer development. One of the major impulses of this new trend came from the discovery of oncometabolites, metabolic intermediates whose abnormal cellular accumulation triggers oncogenic signalling and tumorigenesis. These findings have led to reconsideration and support for the long-forgotten hypothesis of Warburg of altered metabolism as oncogenic driver of cancer and started a novel paradigm whereby mitochondrial metabolites play a pivotal role in malignant transformation. In this review, we describe the evolution of the cancer metabolism research from a historical perspective up to the oncometabolites discovery that spawned the new vision of cancer as a metabolic disease. The oncometabolites' mechanisms of cellular transformation and their contribution to the development of new targeted cancer therapies together with their drawbacks are further reviewed and discussed.

Role of the ABL tyrosine kinases in the epithelial-mesenchymal transition and the metastatic cascade

The ABL kinases, ABL1 and ABL2, promote tumor progression and metastasis in various solid tumors. Recent reports have shown that ABL kinases have increased expression and/or activity in solid tumors and that ABL inactivation impairs metastasis. The therapeutic effects of ABL inactivation are due in part to ABL-dependent regulation of diverse cellular processes related to the epithelial to mesenchymal transition and subsequent steps in the metastatic cascade. ABL kinases target multiple signaling pathways required for promoting one or more steps in the metastatic cascade. These findings highlight the potential utility of specific ABL kinase inhibitors as a novel treatment paradigm for patients with advanced metastatic disease. Video abstract.

Mitochondrial DNA alterations underlie an irreversible shift to aerobic glycolysis in fumarate hydratase-deficient renal cancer

Understanding the mechanisms of the Warburg shift to aerobic glycolysis is critical to defining the metabolic basis of cancer. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an aggressive cancer characterized by biallelic inactivation of the gene encoding the Krebs cycle enzyme fumarate hydratase, an early shift to aerobic glycolysis, and rapid metastasis. We observed impairment of the mitochondrial respiratory chain in tumors from patients with HLRCC. Biochemical and transcriptomic analyses revealed that respiratory chain dysfunction in the tumors was due to loss of expression of mitochondrial DNA (mtDNA)-encoded subunits of respiratory chain complexes, caused by a marked decrease in mtDNA content and increased mtDNA mutations. We demonstrated that accumulation of fumarate in HLRCC tumors inactivated the core factors responsible for replication and proofreading of mtDNA, leading to loss of respiratory chain components, thereby promoting the shift to aerobic glycolysis and disease progression in this prototypic model of glucose-dependent human cancer.

Role of the KEAP1-NRF2 Axis in Renal Cell Carcinoma

NRF2 is a transcription factor that coordinates the antioxidant response in many different tissues, ensuring cytoprotection from endogenous and exogenous stress stimuli. In the kidney, its function is essential in appropriate cellular response to oxidative stress, however its aberrant activation supports progression, metastasis, and resistance to therapies in renal cell carcinoma, similarly to what happens in other nonrenal cancers. While at the moment direct inhibitors of NRF2 are not available, understanding the molecular mechanisms that regulate its hyperactivation in specific tumor types is crucial as it may open new therapeutic perspectives. Here, we focus our attention on renal cell carcinoma, describing how NRF2 hyperactivation can contribute to tumor progression and chemoresistance. Furthermore, we highlight the mechanism whereby the many pathways that are generally altered in these tumors converge to dysregulation of the KEAP1-NRF2 axis.

Fumarate hydratase as a therapeutic target in renal cancer

INTRODUCTION

Renal cell carcinoma (RCC) is a heterogeneous group of cancers that can occur sporadically or as a manifestation of various inherited syndromes. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is one such inherited syndrome that predisposes patients to HLRCC-associated RCC. These tumors are notoriously aggressive and often exhibit early metastases. HLRCC results from germline mutations in the FH gene, which encodes the citric acid cycle enzyme fumarate hydratase (FH). FH loss leads to alterations in oxidative carbon metabolism, necessitating a switch to aerobic glycolysis, as well as a pseudohypoxic response and consequent upregulation of various pro-survival pathways. Mutations in FH also alter tumor cell migratory potential, response to oxidative stress, and response to DNA damage.

AREAS COVERED

We review the mechanisms by which FH loss leads to HLRCC-associated RCC and how these mechanisms are being rationally targeted.

EXPERT OPINION

FH loss results in the activation of numerous salvage pathways for tumor cell survival in HLRCC-associated RCC. Tumor heterogeneity requires individualized characterization via next-generation sequencing, ultimately resulting in HLRCC-specific treatment regimens. As HLRCC-associated RCC represents a classic Warburg tumor, targeting aerobic glycolysis is particularly promising as a future therapeutic avenue.

Oncometabolites and the response to radiotherapy

Radiotherapy (RT) is applied in 45-60% of all cancer patients either alone or in multimodal therapy concepts comprising surgery, RT and chemotherapy. However, despite technical innovations approximately only 50% are cured, highlight a high medical need for innovation in RT practice. RT is a multidisciplinary treatment involving medicine and physics, but has always been successful in integrating emerging novel concepts from cancer and radiation biology for improving therapy outcome. Currently, substantial improvements are expected from integration of precision medicine approaches into RT concepts.Altered metabolism is an important feature of cancer cells and a driving force for malignant progression. Proper metabolic processes are essential to maintain and drive all energy-demanding cellular processes, e.g. repair of DNA double-strand breaks (DSBs). Consequently, metabolic bottlenecks might allow therapeutic intervention in cancer patients.Increasing evidence now indicates that oncogenic activation of metabolic enzymes, oncogenic activities of mutated metabolic enzymes, or adverse conditions in the tumor microenvironment can result in abnormal production of metabolites promoting cancer progression, e.g. 2-hyroxyglutarate (2-HG), succinate and fumarate, respectively. Interestingly, these so-called "oncometabolites" not only modulate cell signaling but also impact the response of cancer cells to chemotherapy and RT, presumably by epigenetic modulation of DNA repair.Here we aimed to introduce the biological basis of oncometabolite production and of their actions on epigenetic regulation of DNA repair. Furthermore, the review will highlight innovative therapeutic opportunities arising from the interaction of oncometabolites with DNA repair regulation for specifically enhancing the therapeutic effects of genotoxic treatments including RT in cancer patients.

Fumarate hydratase-deficient renal cell carcinoma cells respond to asparagine by activation of the unfolded protein response and stimulation of the hexosamine biosynthetic pathway

Background

The loss-of-function mutation of fumarate hydratase (FH) is a driver of hereditary leiomyomatosis and renal cell carcinoma (HLRCC). Fumarate accumulation results in activation of stress-related mechanisms leading to upregulation of cell survival-related genes. To better understand how cells compensate for the loss of FH in HLRCC, we determined the amino acid nutrient requirements of the FH-deficient UOK262 cell line (UOK262) and its FH-repleted control (UOK262WT).

Methods

We determined growth rates and survival of cell lines in response to amino acid depletion and supplementation. RNAseq was used to determine the transcription changes contingent on Asn and Gln supplementation, which was further followed with stable isotope resolved metabolomics (SIRM) using both [U- ¹³C,¹⁵N] Gln and Asn.

Results

We found that Asn increased the growth rate of both cell lines in vitro. Gln, but not Asn, increased oxygen consumption rates and glycolytic reserve of both cell lines. Although Asn was taken up by the cells, there was little evidence of Asn-derived label in cellular metabolites, indicating that Asn was not catabolized. However, Asn strongly stimulated Gln labeling of uracil and precursors, uridine phosphates and hexosamine metabolites in the UOK262 cells and to a much lesser extent in the UOK262WT cells, indicating an activation of the hexosamine biosynthetic pathway (HBP) by Asn. Asn in combination with Gln, but not Asn or Gln alone, stimulated expression of genes associated with the endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in UOK262 to a greater extent than in FH-restored cells. The changes in expression of these genes were confirmed by RT-PCR, and the stimulation of the UPR was confirmed orthogonally by demonstration of an increase in spliced XBP1 (sXBP1) in UOK262 cells under these conditions. Asn exposure also increased both the RNA and protein expression of the HBP regulator GFPT2, which is a transcriptional target of sXBP1.

Conclusions

Asn in the presence of Gln induces an ER stress response in FH-deficient UOK262 cells and stimulates increased synthesis of UDP-acetyl glycans indicative of HBP activity. These data demonstrate a novel effect of asparagine on cellular metabolism in FH-deficient cells that could be exploited therapeutically.

Metabolic programming of tumor associated macrophages in the context of cancer treatment

Tumor associated macrophages (TAMs) are important components of the tumor microenvironment (TME). They are characterized by a remarkable functional plasticity, thereby mostly promoting cancer progression. Changes in immune cell metabolism are paramount for this functional adaptation. Here, we review the functional consequences of the metabolic programming of TAMs and the influence of local and systemic targeted therapies on the metabolic characteristics of the TME that shape the functional phenotype of the TAMs. Understanding these metabolic changes within the context of the cross-talk between the different components of the TME including the TAMs and the tumor cells is an essential step that can pave the way towards identifications of ways to improve responses to different treatments, to overcome resistance to treatments, tumor progression and reduce treatment-specific toxicity.

Nitrogen Trapping as a Therapeutic Strategy in Tumors with Mitochondrial Dysfunction

Under conditions of inherent or induced mitochondrial dysfunction, cancer cells manifest overlapping metabolic phenotypes, suggesting that they may be targeted via a common approach. Here, we use multiple oxidative phosphorylation (OXPHOS)-competent and incompetent cancer cell pairs to demonstrate that treatment with α-ketoglutarate (aKG) esters elicits rapid death of OXPHOS-deficient cancer cells by elevating intracellular aKG concentrations, thereby sequestering nitrogen from aspartate through glutamic-oxaloacetic transaminase 1 (GOT1). Exhaustion of aspartate in these cells resulted in immediate depletion of adenylates, which plays a central role in mediating mTOR inactivation and inhibition of glycolysis. aKG esters also conferred cytotoxicity in a variety of cancer types if their cell respiration was obstructed by hypoxia or by chemical inhibition of the electron transport chain (ETC), both of which are known to increase aspartate and GOT1 dependencies. Furthermore, preclinical mouse studies suggested that cell-permeable aKG displays a good biosafety profile, eliminates aspartate only in OXPHOS-incompetent tumors, and prevents their growth and metastasis. This study reveals a novel cytotoxic mechanism for the metabolite aKG and identifies cell-permeable aKG, either by itself or in combination with ETC inhibitors, as a potential anticancer approach. SIGNIFICANCE: These findings demonstrate that OXPHOS deficiency caused by either hypoxia or mutations, which can significantly increase cancer virulence, renders tumors sensitive to aKG esters by targeting their dependence upon GOT1 for aspartate synthesis. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/17/3492/F1.large.jpg.

Assessing Genomic Copy Number Alterations as Best Practice for Renal Cell Neoplasia: An Evidence-Based Review from the Cancer Genomics Consortium Workgroup

Renal cell neoplasia are heterogeneous with diverse histology, genetic alterations, and clinical behavior that are diagnosed mostly on morphologic features. The Renal Cell Neoplasia Workgroup of the Cancer Genomics Consortium systematically evaluated peer-reviewed literature on genomic studies of renal cell carcinoma (RCC), including clear cell RCC, papillary RCC, chromophobe RCC, and the translocation RCC involving TFE3, TFEB and MITF rearrangements, as well as benign oncocytoma, which together comprise about 95% of all renal cell neoplasia. The Workgroup curated recurrent copy number alterations (CNAs), copy-neutral loss-of-heterozygosity (cnLOH), rearrangements, and mutations, found in each subtype and assigned clinical relevance according to established criteria. In clear cell RCC, loss of 3p has a disease-initiating role and most likely also in progression with mutations detected in VHL and other genes mapped to this arm, and loss of 9p and/or 14q has well-substantiated prognostic utility. Gain of chromosomes 7 and 17 are hallmark CNAs of papillary RCC, but patterns of other CNAs as detected by chromosomal microarray analysis (CMA) afford sub-classification into Type 1 and 2 with prognostic value, and for further sub-stratification of Type 2. Inherent chromosome loss in chromophobe RCC as detected by CMA is useful for distinguishing the eosinophilic variant from benign oncocytoma which in contrast exhibits few CNAs or rearranged CCND1, but share mitochondrial DNA mutations. In morphologically atypical RCCs, rearrangement of TFE3 and TFEB should be considered in the differential diagnosis, portending an aggressive RCC subtype. Overall, this evidence-based review provides a validated role for assessment of CNAs in renal cell neoplasia in the clinical setting to assist in renal cell neoplasm diagnosis and sub-classification within subtypes that is integral to the management of patients, from small incidentally found renal masses to larger surgically resected specimens, and simultaneously identify the presence of key alterations portending outcome in malignant RCC subtypes.

The Tricarboxylic Acid Cycle at the Crossroad Between Cancer and Immunity

Significance: The tricarboxylic acid (TCA) cycle is a housekeeping metabolic pathway essential for generation of energy and biosynthetic intermediates. Alterations of the TCA cycle play a pivotal role in oncogenesis and inflammation. As such, some metabolic vulnerabilities, imposed by TCA cycle dysfunction in cancer, have been identified. Similarly, the TCA cycle appeared as an actionable pathway in immunopathologies. Recent Advances: Metabolic changes accompanying cell transformation have been usually considered as adaptive mechanisms to malignant transformation. The identification of oncogenic mutations in some TCA cycle enzymes changed this view, indicating altered mitochondrial metabolism as an instrumental mechanism for cancer initiation. Similarly, the observation that TCA cycle-derived metabolites have multiple signaling roles in immune cells supports the idea of this pathway as a metabolic rheostat of immune responses. Critical Issues: This review summarizes the crucial role of the TCA cycle in pathophysiology describing the post-translational and epigenetic impact of oncometabolites accumulation in cancer and immune cells. Future Directions: Additional studies will be necessary to further explore the role of oncometabolites in paracrine signaling and to identify genuine metabolic and nutritional liabilities imposed by TCA cycle dysfunction in cancer, hardly to be escaped by resistance mechanisms.

Novel renal medullary carcinoma cell lines, UOK353 and UOK360, provide preclinical tools to identify new therapeutic treatments

Renal medullary carcinoma (RMC) is a rare, aggressive disease that predominantly afflicts individuals of African or Mediterranean descent with sickle cell trait. RMC comprises 1% of all renal cell carcinoma diagnoses with a median overall survival of 13 months. Patients are typically young (median age—22) and male (male:female ratio of 2:1) and tumors are characterized by complete loss of expression of the SMARCB1 tumor suppressor protein. Due to the low incidence of RMC and the disease's aggressiveness, treatment decisions are often based on case reports. Thus, it is critical to develop preclinical models of RMC to better understand the pathogenesis of this disease and to identify effective forms of therapy. Two novel cell line models, UOK353 and UOK360, were derived from primary RMCs that both demonstrated the characteristic SMARCB1 loss. Both cell lines overexpressed EZH2 and other members of the polycomb repressive complex and EZH2 inhibition in RMC tumor spheroids resulted in decreased viability. High throughput drug screening of both cell lines revealed several additional candidate compounds, including bortezomib that had both in vitro and in vivo antitumor activity. The activity of bortezomib was shown to be partially dependent on increased oxidative stress as addition of the N‐acetyl cysteine antioxidant reduced the effect on cell proliferation. Combining bortezomib and cisplatin further decreased cell viability both in vitro and in vivo that single agent bortezomib treatment. The UOK353 and UOK360 cell lines represent novel preclinical models for the development of effective forms of therapy for RMC patients.

Oncometabolites in renal cancer

The study of cancer metabolism has evolved vastly beyond the remit of tumour proliferation and survival with the identification of the role of 'oncometabolites' in tumorigenesis. Simply defined, oncometabolites are conventional metabolites that, when aberrantly accumulated, have pro-oncogenic functions. Their discovery has led researchers to revisit the Warburg hypothesis, first postulated in the 1950s, of aberrant metabolism as an aetiological determinant of cancer. As such, the identification of oncometabolites and their utilization in diagnostics and prognostics, as novel therapeutic targets and as biomarkers of disease, are areas of considerable interest in oncology. To date, fumarate, succinate, L-2-hydroxyglutarate (L-2-HG) and D-2-hydroxyglutarate (D-2-HG) have been characterized as bona fide oncometabolites. Extensive metabolic reprogramming occurs during tumour initiation and progression in renal cell carcinoma (RCC) and three oncometabolites - fumarate, succinate and L-2-HG - have been implicated in this disease process. All of these oncometabolites inhibit a superfamily of enzymes known as α-ketoglutarate-dependent dioxygenases, leading to epigenetic dysregulation and induction of pseudohypoxic phenotypes, and also have specific pro-oncogenic capabilities. Oncometabolites could potentially be exploited for the development of novel targeted therapies and as biomarkers of disease.

Functional Genomics Reveals Synthetic Lethality between Phosphogluconate Dehydrogenase and Oxidative Phosphorylation

The plasticity of a preexisting regulatory circuit compromises the effectiveness of targeted therapies, and leveraging genetic vulnerabilities in cancer cells may overcome such adaptations. Hereditary leiomyomatosis renal cell carcinoma (HLRCC) is characterized by oxidative phosphorylation (OXPHOS) deficiency caused by fumarate hydratase (FH) nullizyogosity. To identify metabolic genes that are synthetically lethal with OXPHOS deficiency, we conducted a genetic loss-of-function screen and found that phosphogluconate dehydrogenase (PGD) inhibition robustly blocks the proliferation of FH mutant cancer cells both in vitro and in vivo. Mechanistically, PGD inhibition blocks glycolysis, suppresses reductive carboxylation of glutamine, and increases the NADP⁺/NADPH ratio to disrupt redox homeostasis. Furthermore, in the OXPHOS-proficient context, blocking OXPHOS using the small-molecule inhibitor IACS-010759 enhances sensitivity to PGD inhibition in vitro and in vivo. Together, our study reveals a dependency on PGD in OXPHOS-deficient tumors that might inform therapeutic intervention in specific patient populations.

Proteasome inhibition disrupts the metabolism of fumarate hydratase- deficient tumors by downregulating p62 and c-Myc

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is characterized by germline mutations of the FH gene that encodes for the TCA cycle enzyme, fumarate hydratase. HLRCC patients are at risk for the development of an aggressive form of type 2 papillary renal cell carcinoma. By studying the mechanism of action of marizomib, a proteasome inhibitor able to cross the blood-brain barrier, we found that it modulates the metabolism of HLRCC cells. Marizomib decreased glycolysis in vitro and in vivo by downregulating p62 and c-Myc. C-Myc downregulation decreased the expression of lactate dehydrogenase A, the enzyme catalyzing the conversion of pyruvate to lactate. In addition, proteasomal inhibition lowered the expression of the glutaminases GLS and GLS2, which support glutamine metabolism and the maintenance of the redox balance. Thus, in HLRCC cells, proteasome inhibition disrupts glucose and glutamine metabolism, restricting nutrients and lowering the cells’ anti-oxidant response capacity. Although the cytotoxicity induced by proteasome inhibitors is complex, the understanding of their metabolic effects in HLRCC may lead to the development of effective therapeutic strategies or to the development of markers of efficacy.

A Phase II Trial of Vandetanib in Children and Adults with Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumor

PURPOSE

Gastrointestinal stromal tumors (GIST) are resistant to cytotoxic chemotherapy and radiotherapy. Most GIST in children are wild-type for KIT and PDGFRA (WT GIST) and deficient in expression of succinate dehydrogenase (dSDH GIST). We tested the activity of vandetanib, an oral small-molecule inhibitor of VEGFR2, EGFR, and RET, in patients with dSDH GIST.

PATIENTS AND METHODS

Phase II study of vandetanib (300 mg orally once daily to patients ≥18 years, and 100 mg/m2/dose to patients < 18 years) on a continuous dosing schedule (1 cycle = 28 days) to assess the clinical activity (partial and complete response rate RECIST v1.1) in patients with dSDH GIST. A Simon optimal two-stage design (target response rate 25%, rule out 5%) was used: If ≥1 of 9 patients in stage 1 responded, enrollment would be expanded to 24 patients, and if ≥3 of 24 responded, vandetanib would be considered active.

RESULTS

Nine patients (7 female and 2 male; median age, 24 years; range, 11-52) with metastatic disease were enrolled. Three of the initial 5 adult patients developed treatment-modifying toxicities. After a protocol amendment, two adults received vandetanib at 200 mg/dose with improved tolerability. The two children (<18 years old) enrolled did not experience treatment-modifying toxicities. No partial or complete responses were observed (median number of cycles, 4; range, 2-18).

CONCLUSIONS

Vandetanib at a dose of 300 mg daily was not well tolerated by adults with dSDH GIST. Two of 9 patients had prolonged stable disease, but no partial or complete responses were observed, and vandetanib is thus not considered active in dSDH GIST.

Microarray analysis of apoptosis gene expression in liver injury induced by chronic exposure to arsenic and high-fat diet in male mice

Rapid growth in the incidence of liver disease is largely attributable to lifestyle and environmental contaminants, which are often overlooked as the leading causes of this problem. Thus, the possible contribution of arsenic (As) to high-fat diet (HFD)-induced liver damage was examined via microarray analysis. To perform this experiment, a total number of 40 healthy adult male NMRI mice (22-30 g) were used. To this end, these animals were randomly assigned to four groups of 10. Oxidative stress and histopathological parameters were also evaluated in the liver of the mice exposed to a minimally cytotoxic concentration of As (50 ppm) in drinking water while being fed with a HFD for 20 weeks. Subsequently, apoptosis gene expression profiling was utilized via real-time (RT) PCR array analysis. The results showed that As had increased the amount of HFD-induced liver damage and consequently amplified changes in oxidative stress factors, histopathological parameters, as well as apoptosis pathway genes. Investigating the expression profile of apoptosis pathway genes similarly revealed that caspase-8, as a main upstream contributor to the apoptosis pathway, might play an important role in the induction of apoptosis generated by As and HFD. Ultimately, this study highlighted that As in drinking water could increase sensitivity in mice to HFD-induced liver disease through strengthening apoptosis pathway.

Reactive Oxygen Species Are Involved in the Development of Gastric Cancer and Gastric Cancer-Related Depression through ABL1-Mediated Inflammation Signaling Pathway

Background

The mechanisms of crosstalk between depression and gastric cancer (GC) remain ill defined. Given that reactive oxygen species (ROS) is involved in the pathophysiology of both GC and depression, we try to explore the activities of ROS in the development of GC and GC-related depression.

Methods

110 patients with newly diagnosed GC were recruited in our study. The clinical characteristics of these patients were recorded. Inflammation and oxidative stress markers were detected by ELISA. The depression status of patients with GC was assessed during follow-up. The association between ROS, ABL1, and inflammation factors was evaluated in H₂O₂-treated GC cell lines and The Cancer Genome Atlas (TCGA) database. The effect of ABL1 on inflammation was detected with Imatinib/Nilotinib-treated GC cell lines. A chronic mild stress- (CMS-) induced patient-derived xenograft (PDX) mice model was established to assess the crosstalk between depression and GC.

Results

Depression was correlated with poor prognosis of patients with GC. GC patients with depression were under a high level of oxidative status as well as dysregulated inflammation. In the CMS-induced GC PDX mice model, CMS could facilitate the development of GC. Additionally, tumor bearing could induce depressive-like behaviors of mice. With the treatment of ROS, the activities of ABL1 and inflammatory signaling were enhanced both in vitro and in vivo, and blocking the activities of ABL1 inhibited inflammatory signaling.

Conclusions

ROS-activated ABL1 mediates inflammation through regulating NF-κB1 and STAT3, which subsequently leads to the development of GC and GC-related depression.

The response of glandular gastric transcriptome to T-2 toxin in chicks

This study was conducted to determine the effect of T-2 toxin on the transcriptome of the glandular stomach in chicks using RNA-sequencing (RNA-Seq). Four groups of 1-day-old Cobb male broilers (n = 4 cages/group, 6 chicks/cage) were fed a corn-soybean-based diet (control) and control supplemented with T-2 toxin at 1.0, 3.0, and 6.0 mg/kg, respectively, for 2 weeks. The histological results showed that dietary supplementation of T-2 toxin at 3.0 and 6.0 mg/kg induced glandular gastric injury including serious inflammation, increased inflammatory cells, mucosal edema, and necrosis and desquamation of the epithelial cells in the glandular stomach of chicks. RNA-Seq analysis revealed that there were 671, 1393, and 1394 genes displayed ≥2 (P < 0.05) differential expression in the dietary supplemental T-2 toxin at 1.0, 3.0, and 6.0 mg/kg, respectively, compared with the control group. Notably, 204 differently expressed genes had shared similar changes among these three doses of T-2 toxin. GO and KEGG pathway analysis results showed that many genes involved in oxidation-reduction process, inflammation, wound healing/bleeding, and apoptosis/carcinogenesis were affected by T-2 toxin exposure. In conclusion, this study systematically elucidated toxic mechanisms of T-2 toxin on the glandular stomach, which might provide novel ideas to prevent adverse effects of T-2 toxin in chicks.

Fumarate hydratase in cancer: A multifaceted tumour suppressor

Cancer is now considered a multifactorial disorder with different aetiologies and outcomes. Yet, all cancers share some common molecular features. Among these, the reprogramming of cellular metabolism has emerged as a key player in tumour initiation and progression. The finding that metabolic enzymes such as fumarate hydratase (FH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH), when mutated, cause cancer suggested that metabolic dysregulation is not only a consequence of oncogenic transformation but that it can act as cancer driver. However, the mechanisms underpinning the link between metabolic dysregulation and cancer remain only partially understood. In this review we discuss the role of FH loss in tumorigenesis, focusing on the role of fumarate as a key activator of a variety of oncogenic cascades. We also discuss how these alterations are integrated and converge towards common biological processes. This review highlights the complexity of the signals elicited by FH loss, describes that fumarate can act as a bona fide oncogenic event, and provides a compelling hypothesis of the stepwise neoplastic progression after FH loss.

The Metabolic Basis of Kidney Cancer

Kidney cancer is not a single disease but represents several distinct types of cancer that have defining histologies and genetic alterations and that follow different clinical courses and have different responses to therapy. Mutation of genes associated with kidney cancer, such as VHL, FLCN, TFE3, FH, or SDHB, dysregulates the tumor's responses to changes in oxygen, iron, nutrient, or energy levels. The identification of these varying genetic bases of kidney cancer has increased our understanding of the biology of this cancer, allowing the development of targeted therapies and the appreciation that it is a cancer driven by metabolic alterations. SIGNIFICANCE: Kidney cancer is a complex disease composed of different types of cancer that present with different histologies, clinical courses, genetic changes, and responses to therapy. This review describes the known genetic changes within kidney cancer, how they alter tumor metabolism, and how these metabolic changes can be therapeutically targeted.

Oncometabolites in cancer aggressiveness and tumour repopulation

Tumour repopulation is recognized as a crucial event in tumour relapse where therapy-sensitive dying cancer cells influence the tumour microenvironment to sustain therapy-resistant cancer cell growth. Recent studies highlight the role of the oncometabolites succinate, fumarate, and 2-hydroxyglutarate in the aggressiveness of cancer cells and in the worsening of the patient's clinical outcome. These oncometabolites can be produced and secreted by cancer and/or surrounding cells, modifying the tumour microenvironment and sustaining an invasive neoplastic phenotype. In this review, we report recent findings concerning the role in cancer development of succinate, fumarate, and 2-hydroxyglutarate and the regulation of their related enzymes succinate dehydrogenase, fumarate hydratase, and isocitrate dehydrogenase. We propose that oncometabolites are crucially involved in tumour repopulation. The study of the mechanisms underlying the relationship between oncometabolites and tumour repopulation is fundamental for identifying efficient anti-cancer therapeutic strategies and novel serum biomarkers in order to overcome cancer relapse.

Germline mutations of renal cancer predisposition genes and clinical relevance in Chinese patients with sporadic, early-onset disease

BACKGROUND

An inherited susceptibility to renal cancers is associated with multiple predisposing genes, but most screening tests are limited to patients with a family history. Next-generation sequencing (NGS)-based multigene panels provide an efficient and adaptable tool for investigating pathogenic germline mutations on a larger scale. This study investigated the frequency of pathogenic germline mutations in renal cancer predisposition genes in patients with sporadic, early-onset disease.

METHODS

An NGS-based panel of 23 known and potential renal cancer predisposition genes was used to analyze germline mutations in 190 unrelated Chinese patients under the age of 45 years who presented with renal tumors. The detected variants were filtered for pathogenicity, and then their frequencies were calculated and correlated with clinical features. Germline variants of the fumarate hydratase (FH) and BRCA1-associated protein 1 (BAP1) genes were comprehensively analyzed because of their aggressive potential.

RESULTS

In total, 18 patients (9.5%) had germline mutations in 10 genes. Twelve of these 18 patients had alterations in renal cancer predisposition genes (6.3%), and 6 patients had mutations in potential predisposition genes such as BRCA1/2. Notably, pathogenic mutation carriers had a significant family history in second-degree relatives in comparison with those without pathogenic mutations (P < .001). Variants of unknown clinical significance in FH and BAP1 demonstrated evidence of additional somatic loss in tumors.

CONCLUSIONS

In patients with early-onset disease, a multigene panel identified a high pathogenic germline mutation rate in renal cancer predisposition genes. This study emphasizes the importance of screening patients with early-onset disease for mutations in cancer predisposition genes. Germline screening should be encouraged in early-onset patients to provide personalized medicine and improve patient outcomes.