Wnt inhibitor screen reveals iron dependence of β-catenin signaling in cancers

Initial gut microbiota composition is a determining factor in the promotion of colorectal cancer by oral iron supplementation: evidence from a murine model

BACKGROUND

Colorectal cancer (CRC) development is influenced by both iron and gut microbiota composition. While iron supplementation is routinely used to manage anemia in CRC patients, it may also impact gut microbiota and promote tumorigenesis. In this study, we investigated the impact of initial gut microbiota composition on iron-promoted tumorigenesis. We performed fecal microbiota transplantation (FMT) in ApcMin/+ mice using samples from healthy controls, CRC patients, and mice, followed by exposure to iron sufficient or iron excess diets.

RESULTS

We found that iron supplementation promoted CRC and resulted in distinct gut microbiota changes in ApcMin/+ mice receiving FMT from CRC patients (FMT-CRC), but not from healthy controls or mice. Oral treatment with identified bacterial strains, namely Faecalibaculum rodentium, Holdemanella biformis, Bifidobacterium pseudolongum, and Alistipes inops, protected FMT-CRC mice against iron-promoted tumorigenesis.

CONCLUSIONS

Our findings suggest that microbiota-targeted interventions may mitigate tumorigenic effects of iron supplementation in anemic patients with CRC.

Wnt signaling pathways in biology and disease: mechanisms and therapeutic advances

The Wnt signaling pathway is critically involved in orchestrating cellular functions such as proliferation, migration, survival, and cell fate determination during development. Given its pivotal role in cellular communication, aberrant Wnt signaling has been extensively linked to the pathogenesis of various diseases. This review offers an in-depth analysis of the Wnt pathway, detailing its signal transduction mechanisms and principal components. Furthermore, the complex network of interactions between Wnt cascades and other key signaling pathways, such as Notch, Hedgehog, TGF-β, FGF, and NF-κB, is explored. Genetic mutations affecting the Wnt pathway play a pivotal role in disease progression, with particular emphasis on Wnt signaling's involvement in cancer stem cell biology and the tumor microenvironment. Additionally, this review underscores the diverse mechanisms through which Wnt signaling contributes to diseases such as cardiovascular conditions, neurodegenerative disorders, metabolic syndromes, autoimmune diseases, and cancer. Finally, a comprehensive overview of the therapeutic progress targeting Wnt signaling was given, and the latest progress in disease treatment targeting key components of the Wnt signaling pathway was summarized in detail, including Wnt ligands/receptors, β-catenin destruction complexes, and β-catenin/TCF transcription complexes. The development of small molecule inhibitors, monoclonal antibodies, and combination therapy strategies was emphasized, while the current potential therapeutic challenges were summarized. This aims to enhance the current understanding of this key pathway.

Can Iron Absorption in Molasses Be Increased with Probiotic Additives? "Molasses with Increased Bioavailability"

Introduction: There are many studies on the chemical and enzymatic interactions of probiotics, and the effects of Lactobacillus plantarum 299v on iron absorption have been clearly shown. The aim of this study was to investigate the effect of probiotics on the absorption of iron in molasses. Material and method: Wistar rats (n = 46) were taken four weeks after birth and divided into seven groups. Iron deficiency anemia was induced by giving "iron purified pellet" to the groups except the control group for four weeks and then the groups were given nutrients for eight weeks. In addition to iron deficiency anemia tests, immunohistochemical markers such as SCL11a, IRE1, Wnt2, and CD71 were examined. Results: The mean weight of the subjects was 309.5 ± 63.9 (226-424) g and no significant difference was observed in the laboratory values of metabolic data. When the laboratory values of iron deficiency anemia were examined, a statistically significant difference was found between the mean ferritin (p = 0.03) and hepcidin (p = 0.02) values of the groups. Discussion: Iron absorption analysis values were generally higher in the group receiving Fe3+ as expected. However, when the groups receiving molasses and additives were compared, the highest plasma iron level and Hb value were found in the Lactobacillus plantarum 299v group, and the highest ferritin and hepcidin levels were found in the Multiprobiotic group. No difference was observed between the body weights and fasting serum glucose levels of the groups despite daily molasses consumption, indicating the metabolic proactive effects of probiotics. Conclusions: Although no significant difference was detected between the groups receiving probiotics, iron absorption in molasses was increased with probiotic supplementation.

Decoding β-catenin associated protein-protein interactions: Emerging cancer therapeutic opportunities

The hyperactive Wnt/β-catenin signaling circuit has been proven to be closely related to the progression of various cancers, with β-catenin serving as a central regulator of pro-tumorigenic processes. Preclinical evidences strongly support β-catenin as a promising therapeutic target. However, it has long been considered "undruggable" due to challenges such as the lack of crystal structures for its N- and C-terminal domains, high mutation rates, and limited availability of inhibitors. Notably, the network of β-catenin-associated protein-protein interactions (PPIs) is vital in the progression of multiple diseases. These interactions form a cancer-specific network that participates in all phases of oncogenesis, from cell metastasis to immunosuppressive microenvironment formation. Thus, researches on these PPIs are essential for unraveling the molecular mechanisms behind tumors with aberrant β-catenin activation, as well as for developing new targeted therapies. In this review, we delve into how β-catenin's PPIs orchestrate cancer progression and highlight biological and clinical dilemmas, proposing frontier technologies and potential challenges in targeting β-catenin for cancer therapy.

Cascade specific endogenous Fe3+ interference and in situ catalysis for tumor therapy with stemness suppression

Cancer stem-like cells (CSCs), featuring high tumorigenicity and invasiveness, are one of the critical factors leading to the failure of clinical cancer treatment such as metastasis and recurrence. However, current strategies suffer from the low stemness-inhibiting efficacy on CSCs by conventional molecular agents and the poor lethal effects against bulk tumor cells. Here we engineer a coordination nanomedicine by 2,5-dihydroxyterephthalic acid (DHT) complexing zinc ions (Zn2+) as a double-effect nanodisrupter of tumor iron (Fe) and redox homeostasis for catalysis-boosted tumor therapy with stemness inhibition. Taking advantage of the much higher binding force of DHT toward Fe3+, this nanomedicine can specifically chelate endogenous Fe3+ into its nanostructure and release Zn2+, and the in situ formed hexacoordinated Fe-DHT conformation is of much enhanced reducibility in order to promote reactive oxygen species (ROS) production in tumors. The nanomedicine-mediated Fe depletion and ROS generation collectively induce CSC differentiation via downregulating the Wnt signaling and inducing forkhead box O3 (FoxO3) activation, respectively. Notably, the combined tumor-selective ROS generation and Zn2+-induced antioxidation dysfunction potently trigger intratumoral oxidative damage leading to both cellular apoptosis and ferroptosis. This nanomedicine, capable of synchronously treating CSCs and bulk tumor cells, has been demonstrated to effectively inhibit the growth, postoperative recurrence and metastasis of orthotopic triple-negative breast tumors in vivo, offering an encouraging candidate of cancer therapeutic agents for treating CSCs-enriched malignancy.

Metal Ion Signaling in Biomedicine

Complex multicellular organisms are composed of distinct tissues involving specialized cells that can perform specific functions, making such life forms possible. Species are defined by their genomes, and differences between individuals within a given species directly result from variations in their genetic codes. While genetic alterations can give rise to disease-causing acquisitions of distinct cell identities, it is now well-established that biochemical imbalances within a cell can also lead to cellular dysfunction and diseases. Specifically, nongenetic chemical events orchestrate cell metabolism and transcriptional programs that govern functional cell identity. Thus, imbalances in cell signaling, which broadly defines the conversion of extracellular signals into intracellular biochemical changes, can also contribute to the acquisition of diseased cell states. Metal ions exhibit unique chemical properties that can be exploited by the cell. For instance, metal ions maintain the ionic balance within the cell, coordinate amino acid residues or nucleobases altering folding and function of biomolecules, or directly catalyze specific chemical reactions. Thus, metals are essential cell signaling effectors in normal physiology and disease. Deciphering metal ion signaling is a challenging endeavor that can illuminate pathways to be targeted for therapeutic intervention. Here, we review key cellular processes where metal ions play essential roles and describe how targeting metal ion signaling pathways has been instrumental to dissecting the biochemistry of the cell and how this has led to the development of effective therapeutic strategies.

Isoxazole based nucleosides induce autophagy through the production of ROS and the suppression of the β-catenin pathway in human colorectal carcinoma cells

β-catenin is frequently implicated in signaling pathways that regulate autophagy, and the production of reactive oxygen species (ROS) has been linked to autophagy activation. Isoxazole-based nucleoside compounds have demonstrated anti-cancer properties. In this study, we report the identification of novel isoxazole-nucleosides as anti-tumor agents and their impact on autophagy in human colorectal carcinoma (CRC) cells. Among the ITP series, ITP-7 and ITP-9 (ITP-7/9) exhibited significant cytotoxicity compared to other compounds. Treatment with ITP-7/9 upregulated the expression of key autophagy-related proteins, including LC3 II, Atg7, and phosphorylated Beclin-1. Additionally, ITP-7/9 promoted the formation of LC3 II puncta and increased the number of AO-stained and MDC-stained cells, indicating enhanced autophagy. ROS levels were elevated following ITP-7/9 exposure, and treatment with N-acetyl l-cysteine (NAC), a ROS inhibitor, reduced the ITP-7/9-induced expression of LC3 II. Furthermore, ITP-7/9 inhibited β-catenin's role as a transcription factor, as observed in ICC assays. Moreover, cells with β-catenin gene deletion exhibited stronger autophagy when treated with ITP-7/9 compared to those treated with ITP-7/9 alone. These findings suggest that ITP-7/9 induces autophagy and promotes CRC cell death by downregulating β-catenin.

Redox-Regulated Iron Metabolism and Ferroptosis in Ovarian Cancer: Molecular Insights and Therapeutic Opportunities

Ovarian cancer (OC), known for its lethality and resistance to chemotherapy, is closely associated with iron metabolism and ferroptosis-an iron-dependent cell death process, distinct from both autophagy and apoptosis. Emerging evidence suggests that dysregulation of iron metabolism could play a crucial role in OC by inducing an imbalance in the redox system, which leads to ferroptosis, offering a novel therapeutic approach. This review examines how disruptions in iron metabolism, which affect redox balance, impact OC progression, focusing on its essential cellular functions and potential as a therapeutic target. It highlights the molecular interplay, including the role of non-coding RNAs (ncRNAs), between iron metabolism and ferroptosis, and explores their interactions with key immune cells such as macrophages and T cells, as well as inflammation within the tumor microenvironment. The review also discusses how glycolysis-related iron metabolism influences ferroptosis via reactive oxygen species. Targeting these pathways, especially through agents that modulate iron metabolism and ferroptosis, presents promising therapeutic prospects. The review emphasizes the need for deeper insights into iron metabolism and ferroptosis within the redox-regulated system to enhance OC therapy and advocates for continued research into these mechanisms as potential strategies to combat OC.

Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer

Targeting ferroptosis, an iron-dependent form of regulated cell death triggered by the lethal overload of lipid peroxides, in cancer therapy is impeded by our limited understanding of the intersection of tumour's metabolic feature and ferroptosis vulnerability. In the present study, arginine is identified as a ferroptotic promoter using a metabolites library. This effect is mainly achieved through arginine's conversion to polyamines, which exerts their potent ferroptosis-promoting property in an H2O2-dependent manner. Notably, the expression of ornithine decarboxylase 1 (ODC1), the critical enzyme catalysing polyamine synthesis, is significantly activated by the ferroptosis signal--iron overload--through WNT/MYC signalling, as well as the subsequent elevated polyamine synthesis, thus forming a ferroptosis-iron overload-WNT/MYC-ODC1-polyamine-H2O2 positive feedback loop that amplifies ferroptosis. Meanwhile, we notice that ferroptotic cells release enhanced polyamine-containing extracellular vesicles into the microenvironment, thereby further sensitizing neighbouring cells to ferroptosis and accelerating the "spread" of ferroptosis in the tumour region. Besides, polyamine supplementation also sensitizes cancer cells or xenograft tumours to radiotherapy or chemotherapy through inducing ferroptosis. Considering that cancer cells are often characterized by elevated intracellular polyamine pools, our results indicate that polyamine metabolism exposes a targetable vulnerability to ferroptosis and represents an exciting opportunity for therapeutic strategies for cancer.

Identification and validation of stemness-based and ferroptosis-related molecular clusters in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with an extremely poor prognosis. Cancer stem cells (CSCs) are considered to be responsible for the poor survival, recurrence and therapy resistance of PDAC. Ferroptosis plays a crucial role in the sustain and survival of CSCs. Here, we employed a rigorous evaluation of multiple datasets to identify a novel stemness-based and ferroptosis-related genes (SFRGs) signature to access the potential prognostic application. This work we retrieved RNA-sequencing and clinical annotation data from the TCGA, ICGC, GTEx and GEO database, and acquired 26 stem cell gene sets and 259 ferroptosis genes from StemChecker database and FerrDb database, respectively. Based on consensus clustering and ssGSEA analysis, we identified two expression patterns of CSCs traits (C1 and C2). Then, WGCNA analysis was implemented to screen out hub module genes correlated with stemness. Furthermore, differential expression analysis, Pearson correlation analysis, and the Least absolute shrinkage and selection operator (LASSO) and Cox regression were performed to identify the SFRGs and to construct model. In addition, the differences in prognosis, tumor microenvironment (TME) components and therapy responses were evaluated between two risk groups. Finally, we verified the most influential marker ARNTL2 experimentally by western blot, qRT-PCR, sphere formation assay, mitoscreen assay, intracellular iron concentration determination and MDA determination assays. In conclusion, we developed a stemness-based and ferroptosis-related prognostic model, which could help predict overall survival for PDAC patients. Targeting ferroptosis may be a promising therapeutic strategy to inhibit PDAC progression by suppressing CSCs.

Multi-omics analysis of disulfidptosis regulators and therapeutic potential reveals glycogen synthase 1 as a disulfidptosis triggering target for triple-negative breast cancer

Disruption of disulfide homeostasis during biological processes can have fatal consequences. Excess disulfides induce cell death in a novel manner, termed as "disulfidptosis." However, the specific mechanism of disulfidptosis has not yet been elucidated. To determine the cancer types sensitive to disulfidptosis and outline the corresponding treatment strategies, we firstly investigated the crucial functions of disulfidptosis regulators pan-cancer at multi-omics levels. We found that different tumor types expressed dysregulated levels of disulfidptosis regulators, most of which had an impact on tumor prognosis. Moreover, we calculated the disulfidptosis activity score in tumors and validated it using multiple independent datasets. Additionally, we found that disulfidptosis activity was correlated with classic biological processes and pathways in various cancers. Disulfidptosis activity was also associated with tumor immune characteristics and could predict immunotherapy outcomes. Notably, the disulfidptosis regulator, glycogen synthase 1 (GYS1), was identified as a promising target for triple-negative breast cancer and validated via in vitro and in vivo experiments. In conclusion, our study elucidated the complex molecular phenotypes and clinicopathological correlations of disulfidptosis regulators in tumors, laying a solid foundation for the development of disulfidptosis-targeting strategies for cancer treatment.

Cepharanthine suppresses APC-mutant colorectal cancers by down-regulating the expression of β-catenin

The aberrant activation of the Wnt/β-catenin signaling pathway is closely associated with the development of various carcinomas, especially colorectal cancers (CRCs), where adenomatous colorectal polyposis (APC) mutations are the most frequently observed, which limits the anti-tumor efficiency of inhibitors targeting the upstream of Wnt/β-catenin pathway. The anti-tumor activity of the naturally occurring alkaloid cepharanthine (CEP) extracted from the plant Stephania cepharantha Hayata has been reported in various types of tumors. We previously observed that its derivatives inhibited the Wnt/β-catenin signaling in liver cancer; however, the specific mechanism remains unknown. In this study, we confirmed CEP can effectively inhibit APC-mutant CRC cell lines (SW480, SW620, LoVo) through disturbing of the Wnt/β-catenin signaling and elucidated the underlying mechanisms. Here, we demonstrate that CEP attenuates the Wnt/β-catenin signaling by decreasing the β-catenin, subsequently impeding the proliferation of APC-mutant CRCs. Moreover, CEP induced β-catenin transcription inhibition rather than the instability of β-catenin protein and mRNA contributes to reduction of β-catenin. Taken together, our findings identify CEP as the first β-catenin transcriptional inhibitor in the modulation of Wnt/β-catenin signaling and indicate CEP as a potential therapeutic option for the treatment of APC-mutated CRCs.

Dietary collagen peptide-chelated trace elements supplementation for breeder hens improves the intestinal health of chick offspring

BACKGROUND

Dietary supplementation with trace elements zinc (Zn), iron (Fe) and manganese (Mn) could promote intestinal development and improve intestinal health. There are, however, few studies examining the possibility that maternal original Zn, Fe and Mn could regulate intestinal development and barrier function in the offspring. This study aimed to investigate how the intestinal growth and barrier function of breeder offspring were affected by collagen peptide-chelated trace elements (PTE; Zn, Fe, Mn).

RESULTS

PTE supplementation in the diet of breeder hens increased the concentrations of Zn, Fe and Mn in egg yolk. Maternal PTE supplementation improved morphological parameters of the intestine (villi height, crypt depth and villi height/crypt depth) and upregulated the mRNA expression level of leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) in the ileum of chick embryos. Furthermore, maternal PTE effect improved villi height/crypt depth of offspring at 1 and 14 days of age, and upregulated Lgr5, Claudin-3 and E-cadherin mRNA expression in the broiler ileum. Additionally, PTE treatment could enhance the intestinal microbial diversity of offspring. Maternal PTE supplementation increased the relative abundance of Clostridiales at the genus level and decreased the relative abundance of Enterococcus in newborn offspring. Moreover, maternal PTE supplementation ameliorated the elevated nuclear factor kappa B, toll-like receptor 4 and interleukin 1β mRNA expression in the ileum of offspring caused by LPS challenge.

CONCLUSION

Maternal PTE supplementation could promote intestinal development and enhance the intestinal barrier function of chicken offspring. © 2023 Society of Chemical Industry.

Iron promotes glycolysis to drive colon tumorigenesis

Colorectal cancer (CRC) is the third most common cancer and is also the third leading cause of cancer-related death in the USA. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Macronutrients such as glucose are energy source for a cell. Many tumor cells exhibit increased aerobic glycolysis. Increased tissue micronutrient iron levels in both mice and humans are also associated with increased colon tumorigenesis. However, if iron drives colon carcinogenesis via affecting glucose metabolism is still not clear. Here we found the intracellular glucose levels in tumor colonoids were significantly increased after iron treatment. 13C-labeled glucose flux analysis indicated that the levels of several labeled glycolytic products were significantly increased, whereas several tricarboxylic acid cycle intermediates were significantly decreased in colonoids after iron treatment. Mechanistic studies showed that iron upregulated the expression of glucose transporter 1 (GLUT1) and mediated an inhibition of the pyruvate dehydrogenase (PDH) complex function via directly binding with tankyrase and/or pyruvate dehydrogenase kinase (PDHK) 3. Pharmacological inhibition of GLUT1 or PDHK reactivated PDH complex function and reduced high iron diet-enhanced tumor formation. In conclusion, excess iron promotes glycolysis and colon tumor growth at least partly through the inhibition of the PDH complex function.

The strategies to cure cancer patients by eradicating cancer stem-like cells

Cancer stem-like cells (CSCs), a subpopulation of cancer cells, possess remarkable capability in proliferation, self-renewal, and differentiation. Their presence is recognized as a crucial factor contributing to tumor progression and metastasis. CSCs have garnered significant attention as a therapeutic focus and an etiologic root of treatment-resistant cells. Increasing evidence indicated that specific biomarkers, aberrant activated pathways, immunosuppressive tumor microenvironment (TME), and immunoevasion are considered the culprits in the occurrence of CSCs and the maintenance of CSCs properties including multi-directional differentiation. Targeting CSC biomarkers, stemness-associated pathways, TME, immunoevasion and inducing CSCs differentiation improve CSCs eradication and, therefore, cancer treatment. This review comprehensively summarized these targeted therapies, along with their current status in clinical trials. By exploring and implementing strategies aimed at eradicating CSCs, researchers aim to improve cancer treatment outcomes and overcome the challenges posed by CSC-mediated therapy resistance.

Mechanism of iron on the intestinal epithelium development in suckling piglets

This study aimed to investigate the mechanism of iron on intestinal epithelium development of suckling piglets. Compared with newborn piglets, 7-day-old and 21-day-old piglets showed changes in the morphology of the jejunum, increased proliferation, differentiated epithelial cells, and expanded enteroids. Intestinal epithelium maturation markers and iron metabolism genes were significantly changed. These results suggest that lactation is a critical stage in intestinal epithelial development, accompanied by changes in iron metabolism. In addition, deferoxamine (DFO) treatment inhibited the activity of intestinal organoids at passage 4 (P4) of 0-day-old piglets, but no significant difference was observed in epithelial maturation markers at passage 1 (P1) and P4, and only argininosuccinate synthetase 1 (Ass1) and β-galactosidase (Gleb) were up-regulated at passage 7 (P7). These results in vitro show that iron deficiency may not directly affect intestinal epithelium development through intestinal stem cells (ISCs). The iron supplementation significantly down-regulated the mRNA expression of interleukin-22 receptor subunit alpha-2 (IL-22RA2) in the jejunum of piglets. Furthermore, the mRNA expression of IL-22 in 7-day-old piglets was significantly higher than that in 0-day-old piglets. Adult epithelial markers were significantly up-regulated in organoids treated with recombinant murine cytokine IL-22. Thus, IL-22 may play a key role in iron-affecting intestinal epithelium development.

Transferrin Receptor-Mediated Iron Uptake Promotes Colon Tumorigenesis

Transferrin receptor (TFRC) is the major mediator for iron entry into a cell. Under excessive iron conditions, TFRC is expected to be reduced to lower iron uptake and toxicity. However, the mechanism whereby TFRC expression is maintained at high levels in iron-enriched cancer cells and the contribution of TFRC to cancer development are enigmatic. Here the work shows TFRC is induced by adenomatous polyposis coli (APC) gene loss-driven β-catenin activation in colorectal cancer, whereas TFRC-mediated intratumoral iron accumulation potentiates β-catenin signaling by directly enhancing the activity of tankyrase. Disruption of TFRC leads to a reduction of colonic iron levels and iron-dependent tankyrase activity, which caused stabilization of axis inhibition protein 2 (AXIN2) and subsequent repression of the β-catenin/c-Myc/E2F Transcription Factor 1/DNA polymerase delta1 (POLD1) axis. POLD1 knockdown, iron chelation, and TFRC disruption increase DNA replication stress, DNA damage response, apoptosis, and reduce colon tumor growth. Importantly, a combination of iron chelators and DNA damaging agents increases DNA damage response and reduces colon tumor cell growth. TFRC-mediated iron import is at the center of a novel feed-forward loop that facilitates colonic epithelial cell survival. This discovery may provide novel strategies for colorectal cancer therapy.

β-catenin-IRP2-primed iron availability to mitochondrial metabolism is druggable for active β-catenin-mediated cancer

BACKGROUND

Although β-catenin signaling cascade is frequently altered in human cancers, targeting this pathway has not been approved for cancer treatment.

METHODS

High-throughput screening of an FDA-approved drug library was conducted to identify therapeutics that selectively inhibited the cells with activated β-catenin. Efficacy of iron chelator and mitochondrial inhibitor was evaluated for suppression of cell proliferation and tumorigenesis. Cellular chelatable iron levels were measured to gain insight into the potential vulnerability of β-catenin-activated cells to iron deprivation. Extracellular flux analysis of mitochondrial function was conducted to evaluate the downstream events of iron deprivation. Chromatin immunoprecipitation, real-time quantitative PCR and immunoblotting were performed to identify β-catenin targets. Depletion of iron-regulatory protein 2 (IRP2), a key regulator of cellular iron homeostasis, was carried out to elucidate its significance in β-catenin-activated cells. Online databases were analyzed for correlation between β-catenin activity and IRP2-TfR1 axis in human cancers.

RESULTS

Iron chelators were identified as selective inhibitors against β-catenin-activated cells. Deferoxamine mesylate, an iron chelator, preferentially repressed β-catenin-activated cell proliferation and tumor formation in mice. Mechanically, β-catenin stimulated the transcription of IRP2 to increase labile iron level. Depletion of IRP2-sequered iron impaired β-catenin-invigorated mitochondrial function. Moreover, mitochondrial inhibitor S-Gboxin selectively reduced β-catenin-associated cell viability and tumor formation.

CONCLUSIONS

β-catenin/IRP2/iron stimulation of mitochondrial energetics is targetable vulnerability of β-catenin-potentiated cancer.

Common and ethnic-specific genetic determinants of hemoglobin concentration between Taiwanese Han Chinese and European Whites: findings from comparative two-stage genome-wide association studies

Human iron nutrition is a result of interplays between genetic and environmental factors. However, there has been scarcity of data on the genetic variants associated with altered iron homeostasis and ethnic-specific associations are further lacking. In this study, we compared between the Taiwanese Han Chinese (HC) and European Whites the genetic determinants of hemoglobin (Hb) concentration, a biochemical parameter that in part reflects the amount of functional iron in the body. Through sex-specific two-stage genome-wide association studies (2S-GWAS), we observed the consistent Hb-association of SNPs in TMPRSS6 (chr 22), ABO (chr 9), and PRKCE (chr 2) across sexes in both ethnic groups. Specific to the Taiwanese HC, the Hb-association of AXIN1, together with other loci near the chr 16 alpha-globin gene cluster, was found novel. On the other hand, majority of the Hb-associated SNPs among Europeans were identified along the chr 6 major histocompatibility complex (MHC) region, which has established roles in immune system control. We report here strong Hb-associations of HFE and members of gene families (SLC17; H2A, H2B, H3, H4, H1; TRIM; ZSCAN, ZKSCAN, ZNF; HLA; BTN, OR), numerous SNPs in/nearby CARMIL1, PRRC2A, PSORS1C1, NOTCH4, TSBP1, C6orf15, and distinct associations with non-coding RNA genes. Our findings provide evidence for both common and ethnic-specific genetic determinants of Hb between East Asians and Caucasians. These will help to further our understanding of the iron and/or erythropoiesis physiology in humans and to identify high risk subgroups for iron imbalances - a primary requirement to meet the goal of precision nutrition for optimal health.

Comparative transcriptome analysis reveals physiological responses in liver tissues of Epinephelus coioides under acute hypoxia stress

Hypoxia is a common stressor for aquatic animals, including Epinephelus coioides, with a considerable impact on sustainable aquaculture. E. coioides is a widely consumed fish in China owing to its high nutritious value and taste. However, water hypoxia caused by high density culture process has become a great threat to E. coioides culture, and its response to hypoxia stress has not been discussed before. Therefore, the aim of this study was to examine the response of E. coioides to acute hypoxia using transcriptomic techniques. To this end, RNA sequencing was performed on the liver tissues of fish exposed to normoxic and hypoxic conditions for 1 h. The results presented 503 differentially expressed genes (DEGs) in the liver tissue of fish exposed to hypoxic condition compared with those in the normoxic group. Enrichment analysis using the Gene Ontology database showed that the DEGs were mainly enriched for functions related to cell apoptosis signaling pathways, insulin resistance, antioxidant enzymes, and glycolysis/gluconeogenesis signaling pathways. KEGG enrichment analysis showed that HIF-1, PI3K-AKT, IL-17, NF-kappa B, and MAPK signaling pathways were significantly enriched by the DEGs. The DEGs were mainly involved in immune response, inflammatory response, cell apoptosis regulation, energy metabolism, and substance metabolism. Additionally, the hypoxia response in E. coioides was mainly regulated via the PI3K-AKT-HIF-1 signaling axis. Overall, the findings of this study contribute to the understanding of hypoxia stress response in E. coioides, and provides target genes for breeding hypoxia-tolerant Epinephelus spp.

Hypoxia-induced lncRNA STEAP3-AS1 activates Wnt/β-catenin signaling to promote colorectal cancer progression by preventing m6A-mediated degradation of STEAP3 mRNA

Background

Hypoxia, a typical hallmark of solid tumors, exhibits an essential role in the progression of colorectal cancer (CRC), in which the dysregulation of long non-coding RNAs (lncRNAs) is frequently observed. However, the underlying mechanisms are not clearly defined.

Methods

The TCGA database was analyzed to identify differential lncRNA expression involved in hypoxia-induced CRC progression. qRT-PCR was conducted to validate the upregulation of lncRNA STEAP3-AS1 in CRC cell lines and tumor-bearing mouse and zebrafish models under hypoxia. ChIP-qRT-PCR was used to detect the transcriptional activation of STEAP3-AS1 mediated by HIF-1α. RNA-seq, fluorescent in situ hybridization, RNA pulldown, RNA immunoprecipitation, co-immunoprecipitation, immunofluorescence and immunoblot experiments were used to ascertain the involved mechanisms. Functional assays were performed in both in vitro and in vivo models to investigate the regulatory role of STEAP3-AS1/STEAP3/Wnt/β-catenin axis in CRC proliferation and metastasis.

Results

Here, we identified a hypoxia-induced antisense lncRNA STEAP3-AS1 that was highly expressed in clinical CRC tissues and positively correlated with poor prognosis of CRC patients. Upregulation of lncRNA STEAP3-AS1, which was induced by HIF-1α-mediated transcriptional activation, facilitated the proliferation and metastasis of CRC cells both in vitro and in vivo. Mechanistically, STEAP3-AS1 interacted competitively with the YTH domain-containing family protein 2 (YTHDF2), a N⁶-methyladenosine (m⁶A) reader, leading to the disassociation of YTHDF2 with STEAP3 mRNA. This effect protected STEAP3 mRNA from m⁶A-mediated degradation, enabling the high expression of STEAP3 protein and subsequent production of cellular ferrous iron (Fe²⁺). Increased Fe²⁺ levels elevated Ser 9 phosphorylation of glycogen synthase kinase 3 beta (GSK3β) and inhibited its kinase activity, thus releasing β-catenin for nuclear translocation and subsequent activation of Wnt signaling to support CRC progression.

Conclusions

Taken together, our study highlights the mechanisms of lncRNA STEAP3-AS1 in facilitating CRC progression involving the STEAP3-AS1/STEAP3/Wnt/β-catenin axis, which may provide novel diagnostic biomarkers or therapeutic targets to benefit CRC treatment.

Graphical abstract

Hypoxia-induced HIF-1α transcriptionally upregulates the expression of lncRNA STEAP3-AS1, which interacts competitively with YTHDF2, thus upregulating mRNA stability of STEAP3 and consequent STEAP3 protein expression. The enhanced STEAP3 expression results in production of cellular ferrous iron (Fe²⁺), which induces the Ser 9 phosphorylation and inactivation of GSK3β, releasing β-catenin for nuclear translocation and contributing to subsequent activation of Wnt signaling to promote CRC progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01638-1.

Theragnostic strategies harnessing the self-renewal pathways of stem-like cells in the acute myeloid leukemia

Acute myelogenous leukemia (AML) is a genetically heterogeneous and aggressive cancer of the Hematopoietic Stem/progenitor cells. It is distinguished by the uncontrollable clonal growth of malignant myeloid stem cells in the bone marrow, venous blood, and other body tissues. AML is the most predominant of leukemias occurring in adults (25%) and children (15-20%). The relapse after chemotherapy is a major concern in the treatment of AML. The overall 5-year survival rate in young AML patients is about 40-45% whereas in the elderly patients it is less than 10%. Leukemia stem-like cells (LSCs) having the ability to self-renew indefinitely, repopulate and persist longer in the G0/G1 phase play a crucial role in the AML relapse and refractoriness to chemotherapy. Hence, novel treatment strategies and diagnostic biomarkers targeting LSCs are being increasingly investigated. Through this review, we have explored the signaling modulations in the LSCs as the theragnostic targets. The significance of the self-renewal pathways in overcoming the treatment challenges in AML has been highlighted.

Understanding the Potential and Risk of Bacterial Siderophores in Cancer

Siderophores are iron chelating molecules produced by nearly all organisms, most notably by bacteria, to efficiently sequester the limited iron that is available in the environment. Siderophores are an essential component of mammalian iron homeostasis and the ongoing interspecies competition for iron. Bacteria produce a broad repertoire of siderophores with a canonical role in iron chelation and the capacity to perform versatile functions such as interacting with other microbes and the host immune system. Siderophores are a vast area of untapped potential in the field of cancer research because cancer cells demand increased iron concentrations to sustain rapid proliferation. Studies investigating siderophores as therapeutics in cancer generally focused on the role of a few siderophores as iron chelators; however, these studies are limited and some show conflicting results. Moreover, siderophores are biologically conserved, structurally diverse molecules that perform additional functions related to iron chelation. Siderophores also have a role in inflammation due to their iron acquisition and chelation properties. These diverse functions may contribute to both risks and benefits as therapeutic agents in cancer. The potential of siderophore-mediated iron and bacterial modulation to be used in the treatment of cancer warrants further investigation. This review discusses the wide range of bacterial siderophore functions and their utilization in cancer treatment to further expand their functional relevance in cancer detection and treatment.

Deferoxamine Inhibits Acute Lymphoblastic Leukemia Progression through Repression of ROS/HIF-1α, Wnt/β-Catenin, and p38MAPK/ERK Pathways

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer, with a feature of easy to induce multidrug resistance and relapse. Abundant studies have proved that iron overload strengthens the growth and metastasis of tumor cells. Herein, we found that deferoxamine (DFO) effectively decreased the concentration of intracellular iron in ALL cells. DFO inhibited proliferation, induced apoptosis, and obstructed cell cycle of ALL cells, whereas DFO and dextriferron (Dex) used in combination significantly decreased the sensitivity of ALL cells to DFO. Reactive oxygen species (ROS) level was reduced in ALL cells treated with DFO, and the combination of DFO and Dex reversed the effects of DFO. In vivo, DFO inhibited mouse tumor growth. Besides, cyclinD1, β-catenin, c-Myc, hypoxia inducible factor 1 (HIF-1), p-p38MAPK, and p-ERK1/2 protein levels were significantly downregulated, and the levels of prolyl hydroxylase-2 (PHD-2) were upregulated after treated with DFO, whereas Dex treatment reversed those in vivo and in vitro. In conclusion, DFO inhibited the proliferation and ALL xenograft tumor growth, obstructed the cell cycle, and induced apoptosis of ALL cells, probably via inactivating the ROS/HIF-1α, Wnt/β-catenin, and p38MAPK/ERK signaling.

Ciclopirox Olamine Exerts Tumor-Suppressor Effects via Topoisomerase II Alpha in Lung Adenocarcinoma

Background

Globally, lung cancer is one of the most malignant tumors, of which lung adenocarcinoma (LUAD) is the most common subtype, with a particularly poor prognosis. Ciclopirox olamine (CPX) is an antifungal drug and was recently identified as a potential antitumor agent. However, how CPX and its mechanism of action function during LUAD remain unclear.

Methods

The effects of CPX on cell proliferation, cell cycle, reactive oxygen species (ROS) levels, and apoptosis were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, colony formation, western blotting, flow cytometry assays, and immunohistochemistry. Global gene expression levels were compared between control and CPX-treated LUAD cells. A LUAD xenograft mouse model was used to evaluate the potential in vivo effects of CPX.

Results

We observed that CPX displayed strong antitumorigenic properties in LUAD cells, inhibited LUAD proliferation, induced ROS production, caused DNA damage, and activated the ATR-CHK1-P53 pathway. Topoisomerase II alpha (TOP2A) is overexpressed in LUAD and associated with a poor prognosis. By analyzing differentially expressed genes (DEGs), TOP2A was significantly down-regulated in CPX-treated LUAD cells. Furthermore, CPX treatment substantially inhibited in vivo LUAD xenograft growth without toxicity or side effects to the hematological system and internal organs.

Conclusions

Collectively, for the first time, we showed that CPX exerted tumor-suppressor effects in LUAD via TOP2A, suggesting CPX could potentially function as a promising chemotherapeutic for LUAD treatment.

Canonical Wnt Signaling in the Pathology of Iron Overload-Induced Oxidative Stress and Age-Related Diseases

Iron accumulates in the vital organs with aging. This is associated with oxidative stress, inflammation, and mitochondrial dysfunction leading to age-related disorders. Abnormal iron levels are linked to neurodegenerative diseases, liver injury, cancer, and ocular diseases. Canonical Wnt signaling is an evolutionarily conserved signaling pathway that regulates many cellular functions including cell proliferation, apoptosis, cell migration, and stem cell renewal. Recent evidences indicate that iron regulates Wnt signaling, and iron chelators like deferoxamine and deferasirox can inhibit Wnt signaling and cell growth. Canonical Wnt signaling is implicated in the pathogenesis of many diseases, and there are significant efforts ongoing to develop innovative therapies targeting the aberrant Wnt signaling. This review examines how intracellular iron accumulation regulates Wnt signaling in various tissues and their potential contribution in the progression of age-related diseases.

Wnt/β-catenin signalling: function, biological mechanisms, and therapeutic opportunities

The Wnt/β-catenin pathway comprises a family of proteins that play critical roles in embryonic development and adult tissue homeostasis. The deregulation of Wnt/β-catenin signalling often leads to various serious diseases, including cancer and non-cancer diseases. Although many articles have reviewed Wnt/β-catenin from various aspects, a systematic review encompassing the origin, composition, function, and clinical trials of the Wnt/β-catenin signalling pathway in tumour and diseases is lacking. In this article, we comprehensively review the Wnt/β-catenin pathway from the above five aspects in combination with the latest research. Finally, we propose challenges and opportunities for the development of small-molecular compounds targeting the Wnt signalling pathway in disease treatment.

Interleukin-24 inhibits the phenotype and tumorigenicity of cancer stem cell in osteosarcoma via downregulation Notch and Wnt/β-catenin signaling

Osteosarcoma frequently presents as recurrence and metastasis, even if the primary lesion was eradicated and/or radiotherapy and chemotherapy were administered. Osteosarcoma cancer stem cells (CSCs) are one of the key factors for the recurrence and metastasis of osteosarcoma. We have shown that interleukin-24 (IL-24) inhibits osteosarcoma cell proliferation, migration and invasion in vitro. In the current study, we investigated the role of IL-24 in inhibiting the growth of osteosarcoma CSCs. IL-24 inhibited proliferation and invasion and decreased the stemness of osteosarcoma CSCs in vitro. In a nude mouse xenograft model, IL-24 significantly inhibited the growth of tumors originating from osteosarcoma CSCs. Moreover, we found that IL-24 was able to inactivate both Notch and Wnt/β-Catenin signaling, which are important for the development of the biological characteristics of CSCs. These data demonstrate that IL-24 is able to kill not only cancer cells but also CSCs in osteosarcoma, suggesting that IL-24 might eradicate osteosarcoma and enhance long-term cure rates in patients with osteosarcoma.

Ferroptosis: Cancer Stem Cells Rely on Iron until "to Die for" It

Cancer stem cells (CSCs) are a distinct subpopulation of tumor cells with stem cell-like features. Able to initiate and sustain tumor growth and mostly resistant to anti-cancer therapies, they are thought responsible for tumor recurrence and metastasis. Recent accumulated evidence supports that iron metabolism with the recent discovery of ferroptosis constitutes a promising new lead in the field of anti-CSC therapeutic strategies. Indeed, iron uptake, efflux, storage and regulation pathways are all over-engaged in the tumor microenvironment suggesting that the reprogramming of iron metabolism is a crucial occurrence in tumor cell survival. In particular, recent studies have highlighted the importance of iron metabolism in the maintenance of CSCs. Furthermore, the high concentration of iron found in CSCs, as compared to non-CSCs, underlines their iron addiction. In line with this, if iron is an essential macronutrient that is nevertheless highly reactive, it represents their Achilles’ heel by inducing ferroptosis cell death and therefore providing opportunities to target CSCs. In this review, we first summarize our current understanding of iron metabolism and its regulation in CSCs. Then, we provide an overview of the current knowledge of ferroptosis and discuss the role of autophagy in the (regulation of) ferroptotic pathways. Finally, we discuss the potential therapeutic strategies that could be used for inducing ferroptosis in CSCs to treat cancer.

Efficient induction and sustenance of pluripotent stem cells from bovine somatic cells

Although derivation of naïve bovine embryonic stem cells is unachieved, the possibility for generation of bovine induced pluripotent stem cells (biPSCs) has been generally reported. However, attempts to sustain biPSCs by promoting self-renewal have not been successful. Methods established for maintaining murine and human induced pluripotent stem cells (iPSCs) do not support self-renewal of iPSCs for any bovid species. In this study, we examined methods to enhance complete reprogramming and concurrently investigated signaling relevant to pluripotency of the bovine blastocyst inner cell mass (ICM). First, we identified that forced expression of SV40 large T antigen together with the reprogramming genes (OCT4, SOX2, KLF4 and MYC) substantially enhanced the reprogramming efficacy of bovine fibroblasts to biPSCs. Second, we uncovered that TGFβ signaling is actively perturbed in the ICM. Inhibition of ALK4/5/7 to block TGFβ/activin/nodal signaling together with GSK3β and MEK1/2 supported robust in vitro self-renewal of naïve biPSCs with unvarying colony morphology, steady expansion, expected pluripotency gene expression and committed differentiation plasticity. Core similarities between biPSCs and stem cells of the 16-cell-stage bovine embryo indicated a stable ground state of pluripotency; this allowed us to reliably gain predictive understanding of signaling in bovine pluripotency using systems biology approaches. Beyond defining a high-fidelity platform for advancing biPSC-based biotechnologies that have not been previously practicable, these findings also represent a significant step towards understanding corollaries and divergent aspects of bovine pluripotency.

This article has an associated First Person interview with the joint first authors of the paper.

Summary: Pluripotency reprogramming by overcoming the stable epigenome of bovine cells, and uncovering precise early embryo self-renewal mechanisms enables sustenance and expansion of authentic induced pluripotent stem cells in vitro.

Endolysosome iron restricts Tat-mediated HIV-1 LTR transactivation by increasing HIV-1 Tat oligomerization and β-catenin expression

HIV-1 transactivator of transcription (Tat) protein is required for HIV-1 replication, and it has been implicated in the pathogenesis of HIV-1-associated neurocognitive disorder (HAND). HIV-1 Tat can enter cells via receptor-mediated endocytosis where it can reside in endolysosomes; upon its escape from these acidic organelles, HIV-1 Tat can enter the cytosol and nucleus where it activates the HIV-1 LTR promoter. Although it is known that HIV-1 replication is affected by the iron status of people living with HIV-1 (PLWH), very little is known about how iron affects HIV-1 Tat activation of the HIV-1 LTR promoter. Because HIV-1 proteins de-acidify endolysosomes and endolysosome de-acidification affects subcellular levels and actions of iron, we tested the hypothesis that the endolysosome pool of iron is sufficient to affect Tat-induced HIV-1 LTR transactivation. Ferric (Fe3+) and ferrous (Fe2+) iron both restricted Tat-mediated HIV-1 LTR transactivation. Chelation of endolysosome iron with deferoxamine (DFO) and 2-2 bipyridyl, but not chelation of cytosolic iron with deferiprone and deferasirox, significantly enhanced Tat-mediated HIV-1 LTR transactivation. In the presence of iron, HIV-1 Tat increasingly oligomerized and DFO prevented the oligomerization. DFO also reduced protein expression levels of the HIV-1 restriction agent beta-catenin in the cytosol and nucleus. These findings suggest that DFO increases HIV-1 LTR transactivation by increasing levels of the more active dimeric form of Tat relative to the less active oligomerized form of Tat, increasing the escape of dimeric Tat from endolysosomes, and/or reducing beta-catenin protein expression levels. Thus, intracellular iron might play a significant role in regulating HIV-1 replication, and these findings raise cautionary notes for chelation therapies in PLWH.

Nuclear factor erythroid 2-related factor 2 and β-Catenin Coactivation in Hepatocellular Cancer: Biological and Therapeutic Implications

BACKGROUND AND AIMS

HCC remains a major unmet clinical need. Although activating catenin beta-1 (CTNNB1) mutations are observed in prominent subsets of HCC cases, these by themselves are insufficient for hepatocarcinogenesis. Coexpression of mutant CTNNB1 with clinically relevant co-occurrence has yielded HCCs. Here, we identify cooperation between β-catenin and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling in HCC.

APPROACH AND RESULTS

Public HCC data sets were assessed for concomitant presence of CTNNB1 mutations and either mutations in nuclear factor erythroid-2-related factor-2 (NFE2L2) or Kelch like-ECH-associated protein 1 (KEAP1), or Nrf2 activation by gene signature. HCC development in mice and similarity to human HCC subsets was assessed following coexpression of T41A-CTNNB1 with either wild-type (WT)-, G31A-, or T80K-NFE2L2. Based on mammalian target of rapamycin complex 1 activation in CTNNB1-mutated HCCs, response of preclinical HCC to mammalian target of rapamycin (mTOR) inhibitor was investigated. Overall, 9% of HCC cases showed concomitant CTNNB1 mutations and Nrf2 activation, subsets of which were attributable to mutations in NFE2L2/KEAP1. Coexpression of mutated CTNNB1 with mutant NFE2L2, but not WT-NFE2L2, led to HCC development and mortality by 12-14 weeks. These HCCs were positive for β-catenin targets, like glutamine synthetase and cyclin-D1, and Nrf2 targets, like NAD(P)H quinone dehydrogenase 1 and peroxiredoxin 1. RNA-sequencing and pathway analysis showed high concordance of preclinical HCC to human HCC subset showing activation of unique (iron homeostasis and glioblastoma multiforme signaling) and expected (glutamine metabolism) pathways. NFE2L2-CTNNB1 HCC mice were treated with mTOR inhibitor everolimus (5-mg/kg diet ad libitum), which led to >50% decrease in tumor burden.

CONCLUSIONS

Coactivation of β-catenin and Nrf2 is evident in 9% of all human HCCs. Coexpression of mutant NFE2L2 and mutant CTNNB1 led to clinically relevant HCC development in mice, which responded to mTOR inhibitors. Thus, this model has both biological and therapeutic implications.

Wnt/β-catenin inhibitor ICG-001 enhances the antitumor efficacy of radiotherapy by increasing radiation-induced DNA damage and improving tumor immune microenvironment in hepatocellular carcinoma

BACKGROUND AND PURPOSE

Radiotherapy (RT) has a promising anti-tumor effect depending on its effects on both cancer cells and tumor immune microenvironment (TIME). As one of the most common alterations in hepatocellular carcinoma (HCC), wnt/β-catenin pathway activation, has been reported to induce radioresistance and suppressive TIME. In this study, we aim to explore the effect of wnt/β-catenin inhibitor ICG-001 on radiosensitivity and RT-related TIME of HCC and the underlying mechanism.

MATERIALS AND METHODS

C57BL/6 and nude mouse tumor models were used to evaluate the efficacy of different treatments on tumor growth, recurrence and mice survival. Flow cytometry was performed to assess tumor infiltrating lymphocytes (TILs). DNA damage response (DDR) and radioresistance was investigated by colony formation assays, γ-H2AX and micronuclei measurements.

RESULTS

The addition of ICG-001 to RT exhibited better anti-tumor and survival-prolong efficacy in C57BL/6 than nude mice. TILs analysis revealed that ICG-001 plus RT boosted the infiltration and IFN-γ production of TIL CD8⁺ T cells, meanwhile reduced the number of Tregs. Moreover, mechanistic study demonstrated that ICG-001 increased the radiation-induced DDR of HCC cells by suppressing p53, thus leading to stronger activation of cGAS/STING pathway. Utilization of cGAS/STING pathway inhibitors impaired the therapeutic effect of combination therapy. Furthermore, combination therapy led to stronger immunologic memory and tumor relapse prevention.

CONCLUSIONS

Our findings showed that ICG-001 displayed both local and systematic effects by increasing radiosensitivity and improving immunity in HCC, which indicated that ICG-001 might be a potential synergetic treatment for radiotherapy and radioimmunotherapy in HCC patients.

Fosciclopirox suppresses growth of high-grade urothelial cancer by targeting the γ-secretase complex

Ciclopirox (CPX) is an FDA-approved topical antifungal agent that has demonstrated preclinical anticancer activity in a number of solid and hematologic malignancies. Its clinical utility as an oral anticancer agent, however, is limited by poor oral bioavailability and gastrointestinal toxicity. Fosciclopirox, the phosphoryloxymethyl ester of CPX (Ciclopirox Prodrug, CPX-POM), selectively delivers the active metabolite, CPX, to the entire urinary tract following parenteral administration. We characterized the activity of CPX-POM and its major metabolites in in vitro and in vivo preclinical models of high-grade urothelial cancer. CPX inhibited cell proliferation, clonogenicity and spheroid formation, and increased cell cycle arrest at S and G0/G1 phases. Mechanistically, CPX suppressed activation of Notch signaling. Molecular modeling and cellular thermal shift assays demonstrated CPX binding to γ-secretase complex proteins Presenilin 1 and Nicastrin, which are essential for Notch activation. To establish in vivo preclinical proof of principle, we tested fosciclopirox in the validated N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) mouse bladder cancer model. Once-daily intraperitoneal administration of CPX-POM for four weeks at doses of 235 mg/kg and 470 mg/kg significantly decreased bladder weight, a surrogate for tumor volume, and resulted in a migration to lower stage tumors in CPX-POM treated animals. This was coupled with a reduction in the proliferation index. Additionally, there was a reduction in Presenilin 1 and Hes-1 expression in the bladder tissues of CPX-POM treated animals. Following the completion of the first-in-human Phase 1 trial (NCT03348514), the pharmacologic activity of fosciclopirox is currently being characterized in a Phase 1 expansion cohort study of muscle-invasive bladder cancer patients scheduled for cystectomy (NCT04608045) as well as a Phase 2 trial of newly diagnosed and recurrent urothelial cancer patients scheduled for transurethral resection of bladder tumors (NCT04525131).

Effects of Environmental Conditions on Nephron Number: Modeling Maternal Disease and Epigenetic Regulation in Renal Development

A growing body of evidence suggests that low nephron numbers at birth can increase the risk of chronic kidney disease or hypertension later in life. Environmental stressors, such as maternal malnutrition, medication and smoking, can influence renal size at birth. Using metanephric organ cultures to model single-variable environmental conditions, models of maternal disease were evaluated for patterns of developmental impairment. While hyperthermia had limited effects on renal development, fetal iron deficiency was associated with severe impairment of renal growth and nephrogenesis with an all-proximal phenotype. Culturing kidney explants under high glucose conditions led to cellular and transcriptomic changes resembling human diabetic nephropathy. Short-term high glucose culture conditions were sufficient for long-term alterations in DNA methylation-associated epigenetic memory. Finally, the role of epigenetic modifiers in renal development was tested using a small compound library. Among the selected epigenetic inhibitors, various compounds elicited an effect on renal growth, such as HDAC (entinostat, TH39), histone demethylase (deferasirox, deferoxamine) and histone methyltransferase (cyproheptadine) inhibitors. Thus, metanephric organ cultures provide a valuable system for studying metabolic conditions and a tool for screening for epigenetic modifiers in renal development.

Ciclopirox olamine induces ferritinophagy and reduces cyst burden in polycystic kidney disease

Despite the recent launch of tolvaptan, the search for safer polycystic kidney disease (PKD) drugs continues. Ciclopirox (CPX) or its olamine salt (CPX-O) is contained in a number of commercially available antifungal agents. CPX is also reported to possess anticancer activity. Several mechanisms of action have been proposed, including chelation of iron and inhibition of iron-dependent enzymes. Here, we show that CPX-O inhibited in vitro cystogenesis of primary human PKD cyst-lining epithelial cells cultured in a 3D collagen matrix. To assess the in vivo role of CPX-O, we treated PKD mice with CPX-O. CPX-O reduced the kidney-to-body weight ratios of PKD mice. The CPX-O treatment was also associated with decreased cell proliferation, decreased cystic area, and improved renal function. Ferritin levels were markedly elevated in cystic kidneys of PKD mice, and CPX-O treatment reduced renal ferritin levels. The reduction in ferritin was associated with increased ferritinophagy marker nuclear receptor coactivator 4, which reversed upon CPX-O treatment in PKD mice. Interestingly, these effects on ferritin appeared independent of iron. These data suggest that CPX-O can induce ferritin degradation via ferritinophagy, which is associated with decreased cyst growth progression in PKD mice. Most importantly these data indicate that CPX-O has the potential to treat autosomal dominant PKD.

Itraconazole attenuates the stemness of nasopharyngeal carcinoma cells via triggering ferroptosis

Radiotherapy is a common therapy method for nasopharyngeal carcinoma (NPC) treatment; however, radioresistance greatly limits the clinical efficiency and prognosis of NPC patients. Therefore, it is extremely urgent to reveal the underlying mechanism contributing to radioresistance and find possible diagnostic biomarkers. Here, we collected the spheroids formed by NPC cells, which had been confirmed to hold the stem cell-like traits, and found that these spheroids exhibited a certain degree of radioresistance. Additionally, NPC spheroids displayed a certain degree of ferroptosis resistance, as evident by the decrease of iron concentration in lysosomes and lipid peroxides oxygen, and increase of glutathione (GSH) level. Furthermore, we revealed that itraconazole triggered the ferroptosis of NPC spheroids, which is characterized as the increase of iron concentration and lipid peroxides oxygen, and decrease of GSH level, and decreased the cell viability of NPC spheroids. Notably, itraconazole partially reversed the radioresistance of NPC spheroids. Mechanistically, we found that itraconazole can sequester iron in lysosome and thus trigger ferroptosis; this is essential for itraconazole-mediated attenuation on NPC spheroid stemness. Therefore, this study provides evidences showing that itraconazole might be used for killing NPC stem cells and thus attenuate radioresistance.

Deferasirox induces cyclin D1 degradation and apoptosis in mantle cell lymphoma in a reactive oxygen species- and GSK3β-dependent mechanism

Mantle cell lymphoma (MCL) is a difficult-to-treat B-cell malignancy characterized by cyclin D1 (CD1) overexpression. Targeting CD1 in MCL has been shown to be of therapeutic significance. However, treatment of MCL remains challenging since patients are still subject to early and frequent relapse of the disease. To ensure their high proliferation rate, tumour cells have increased iron needs, making them more susceptible to iron deprivation. Indeed, several iron chelators proved to be effective anti-cancer agents. In this study, we demonstrate that the clinically approved iron chelator deferasirox (DFX) exerts an anti-tumoural effect in MCL cell lines and patient cells. The exposure of MCL cells to clinically feasible concentrations of DFX resulted in growth inhibition, cell cycle arrest and induction of apoptosis. We show that DFX unfolds its cytotoxic effect by a rapid induction of reactive oxygen species (ROS) that leads to oxidative stress and severe DNA damage and by triggering CD1 proteolysis in a mechanism that requires its phosphorylation on T286 by glycogen synthase kinase-3β (GSK3β). Moreover, we demonstrate that DFX mediates CD1 proteolysis by repressing the phosphatidylinositol 3-kinase (PI3K)/AKT/GSK3β pathway via ROS generation. Our data suggest DFX as a potential therapeutic option for MCL and paves the way for more treatment options for these patients.

Reversing oncogenic transformation with iron chelation

Cancer cells accumulate iron to supplement their aberrant growth and metabolism. Depleting cells of iron by iron chelators has been shown to be selectively cytotoxic to cancer cells in vitro and in vivo. Iron chelators are effective at combating a range of cancers including those which are difficult to treat such as androgen insensitive prostate cancer and cancer stem cells. This review will evaluate the impact of iron chelation on cancer cell survival and the underlying mechanisms of action. A plethora of studies have shown iron chelators can reverse some of the major hallmarks and enabling characteristics of cancer. Iron chelators inhibit signalling pathways that drive proliferation, migration and metastasis as well as return tumour suppressive signalling. In addition to this, iron chelators stimulate apoptotic and ER stress signalling pathways inducing cell death even in cells lacking a functional p53 gene. Iron chelators can sensitise cancer cells to PARP inhibitors through mimicking BRCAness; a feature of cancers trademark genomic instability. Iron chelators target cancer cell metabolism, attenuating oxidative phosphorylation and glycolysis. Moreover, iron chelators may reverse the major characteristics of oncogenic transformation. Iron chelation therefore represent a promising selective mode of cancer therapy.

A perspective on medicinal chemistry approaches towards adenomatous polyposis coli and Wnt signal based colorectal cancer inhibitors

Colorectal cancer (CRC) is one of the major causes of carcinogenic mortality in numbers only after lung and breast cancers. The mutations in adenomatous polyposis coli (APC) gene leads to formation of colorectal polyps in the colonic region and which develop as a malignant tumour upon coalition with patient related risk factors. The protein-protein interaction (PPI) of APC with Asef (A Rac specific guanine nucleotide exchange factor) overwhelms the patient's conditions by rapidly spreading in the entire colorectal region. Most mutations in APC gene occur in mutated cluster region (MCR), where it specifically binds with the cytosolic β-catenin to regulate the Wnt signalling pathway required for CRC cell adhesion, invasion, progression, differentiation and stemness in initial cell cycle phages. The current broad spectrum perspective is attempted to elaborate the sources of identification, development of selective APC inhibitors by targeting emopamil-binding protein (EBP) & dehydrocholesterol reductase-7 & 24 (DHCR-7 & 24); APC-Asef, β-catenin/APC, Wnt/β-catenin, β-catenin/TCF4 PPI inhibitors with other vital Wnt signal cellular proteins and APC/Pol-β interface of colorectal cancer. In this context, this perspective would serve as a platform for design of new medicinal agents by targeting cellular essential components which could accelerate anti-colorectal potential candidates.

Iron: An Essential Element of Cancer Metabolism

Cancer cells undergo considerable metabolic changes to foster uncontrolled proliferation in a hostile environment characterized by nutrient deprivation, poor vascularization and immune infiltration. While metabolic reprogramming has been recognized as a hallmark of cancer, the role of micronutrients in shaping these adaptations remains scarcely investigated. In particular, the broad electron-transferring abilities of iron make it a versatile cofactor that is involved in a myriad of biochemical reactions vital to cellular homeostasis, including cell respiration and DNA replication. In cancer patients, systemic iron metabolism is commonly altered. Moreover, cancer cells deploy diverse mechanisms to increase iron bioavailability to fuel tumor growth. Although iron itself can readily participate in redox reactions enabling vital processes, its reactivity also gives rise to reactive oxygen species (ROS). Hence, cancer cells further rely on antioxidant mechanisms to withstand such stress. The present review provides an overview of the common alterations of iron metabolism occurring in cancer and the mechanisms through which iron promotes tumor growth.

Effects of iron on intestinal development and epithelial maturation of suckling piglets

The purpose of the present study was to discover the effects of iron on the intestinal development and epithelial maturation of suckling piglets. Twenty-seven newborn male piglets from 9 sows (3 piglets per sow), with similar body weight, were selected. The 3 piglets from the same sow were randomly divided into 1 of the 3 groups. The piglets were orally administrated with 2 mL of normal saline (CON group) or with 25 mg of iron by ferrous sulfate (OAFe group; dissolved in normal saline) on the 2nd, 7th, 12th, and 17th day, respectively, or intramuscularly injected with 100 mg of iron by iron dextran (IMFe group) on the 2nd day. The slaughter was performed on the 21st day and intestinal samples were collected. Compared with the CON group, iron supplementation significantly increased the length (P < 0.001), weight (P < 0.001), relative weight (P < 0.001), and the length:weight ratio (P < 0.001) of the small intestine in both OAFe and IMFe groups. The villus height (P < 0.001), crypt depth (CD) (P < 0.001), villus width (P = 0.002), and surface area (P < 0.001) in the jejunum of IMFe and OAFe piglets were also greater than those in CON piglets. The mRNA expression of trehalase (Treh; P = 0.002) and sucrase isomaltase (Sis; P = 0.043), markers of epithelial maturation, increased in OAFe and IMFe piglets, respectively. Moreover, enterocyte vacuolization, observed in fetal-type enterocyte, was reduced in OAFe and IMFe piglets, compared with CON piglets. However, no significant difference in the expression of the target genes of wnt/β-catenin signaling pathway was observed. The results indicated that both oral administration and intramuscular injection with iron promoted intestinal development and epithelial maturation in suckling piglets and that the effects of iron may be independent of wnt/β-catenin signaling.

Fenofibrate prevents iron induced activation of canonical Wnt/β-catenin and oxidative stress signaling in the retina

Accumulating evidence strongly implicates iron in the pathogenesis of aging and disease. Iron levels have been found to increase with age in both the human and mouse retinas. We and others have shown that retinal diseases such as age-related macular degeneration and diabetic retinopathy are associated with disrupted iron homeostasis, resulting in retinal iron accumulation. In addition, hereditary disorders due to mutation in one of the iron regulatory genes lead to age dependent retinal iron overload and degeneration. However, our knowledge on whether iron toxicity contributes to the retinopathy is limited. Recently, we reported that iron accumulation is associated with the upregulation of retinal and renal renin-angiotensin system (RAS). Evidences indicate that multiple genes/components of the RAS are targets of Wnt/β-catenin signaling. Interestingly, aberrant activation of Wnt/β-catenin signaling is observed in several degenerative diseases. In the present study, we explored whether iron accumulation regulates canonical Wnt signaling in the retina. We found that in vitro and in vivo iron treatment resulted in the upregulation of Wnt/β-catenin signaling and its downstream target genes including renin-angiotensin system in the retina. We confirmed further that iron activates canonical Wnt signaling in the retina using TOPFlash T-cell factor/lymphoid enhancer factor promoter assay and Axin2-LacZ reporter mouse. The presence of an iron chelator or an antioxidant reversed the iron-mediated upregulation of Wnt/β-catenin signaling in retinal pigment epithelial (RPE) cells. In addition, treatment of RPE cells with peroxisome proliferator-activated receptor (PPAR) α-agonist fenofibrate prevented iron-induced activation of oxidative stress and Wnt/β-catenin signaling by chelating the iron. The role of fenofibrate, an FDA-approved drug for hyperlipidemia, as an iron chelator has potentially significant therapeutic impact on iron associated degenerative diseases.

Iron and Cancer: 2020 Vision

New and provocative insights into the relationships between iron and cancer have been uncovered in recent years. These include delineation of connections that link cellular iron to DNA repair, genomic integrity, and oncogenic signaling as well as the discovery of ferroptosis, a novel iron-dependent form of cell death. In parallel, new molecules and pathways that regulate iron influx, intracellular iron trafficking, and egress in normal cells, and their perturbations in cancer have been discovered. In addition, insights into the unique properties of iron handling in tumor-initiating cells (cancer stem cells), novel contributions of the tumor microenvironment to the uptake and regulation of iron in cancer cells, and new therapeutic modalities that leverage the iron dependence of cancer have emerged.

Iron chelation inhibits mTORC1 signaling involving activation of AMPK and REDD1/Bnip3 pathways

The mammalian target of rapamycin (mTOR) functions as two complexes (mTORC1 and mTORC2), regulating cell growth and metabolism. Aberrant mTOR signaling occurs frequently in cancers, so mTOR has become an attractive target for cancer therapy. Iron chelators have emerged as promising anticancer agents. However, the mechanisms underlying the anticancer action of iron chelation are not fully understood. Particularly, reports on the effects of iron chelation on mTOR complexes are inconsistent or controversial. Here, we found that iron chelators consistently inhibited mTORC1 signaling, which was blocked by pretreatment with ferrous sulfate. Mechanistically, iron chelation-induced mTORC1 inhibition was not related to ROS induction, copper chelation, or PP2A activation. Instead, activation of AMPK pathway mainly and activation of both HIF-1/REDD1 and Bnip3 pathways partially contribute to iron chelation-induced mTORC1 inhibition. Our findings indicate that iron chelation inhibits mTORC1 via multiple pathways and iron is essential for mTORC1 activation.

Iron: The cancer connection

Iron plays an essential role in normal biological processes: The generation of cellular energy, oxygen transport, DNA synthesis and repair are all processes that require iron-coordinated proteins, either as elemental iron, heme or iron-sulfur clusters. As a transition metal with two major biological oxidation states, iron is also a critical intermediate in the generation of reactive oxygen species that can damage cellular structures and contribute to both aging and cancer. In this review, we focus on experimental and epidemiologic evidence that links iron and cancer, as well as strategies that have been proposed to either reduce or increase cellular iron for cancer therapy.

Role of Divalent Cations in HIV-1 Replication and Pathogenicity

Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.

Altered Iron Metabolism and Impact in Cancer Biology, Metastasis, and Immunology

Iron is an essential nutrient that plays a complex role in cancer biology. Iron metabolism must be tightly controlled within cells. Whilst fundamental to many cellular processes and required for cell survival, excess labile iron is toxic to cells. Increased iron metabolism is associated with malignant transformation, cancer progression, drug resistance and immune evasion. Depleting intracellular iron stores, either with the use of iron chelating agents or mimicking endogenous regulation mechanisms, such as microRNAs, present attractive therapeutic opportunities, some of which are currently under clinical investigation. Alternatively, iron overload can result in a form of regulated cell death, ferroptosis, which can be activated in cancer cells presenting an alternative anti-cancer strategy. This review focuses on alterations in iron metabolism that enable cancer cells to meet metabolic demands required during different stages of tumorigenesis in relation to metastasis and immune response. The strength of current evidence is considered, gaps in knowledge are highlighted and controversies relating to the role of iron and therapeutic targeting potential are discussed. The key question we address within this review is whether iron modulation represents a useful approach for treating metastatic disease and whether it could be employed in combination with existing targeted drugs and immune-based therapies to enhance their efficacy.