Labile Iron Release Primes Pancreatic Cancer for Ferroptosis
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ABSTRACT:
PROVIDER: PRJNA662926 | ENA |
REPOSITORIES: ENA
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Project description:Cancers have unique metabolic adaptations in response to cell-intrinsic and environmental stressors, where identifying new strategies to target these adaptions is an area of active research. We previously described a dependency on a cytosolic aspartate aminotransaminase (GOT1)-dependent pathway for NADPH generation in pancreatic cancer. Here, we sought to identify metabolic dependencies following GOT1 inhibition to provide insight into the regulation of redox metabolism. Using pharmacological methods, we identified cysteine, glutathione, and lipid antioxidant function as metabolic vulnerabilities following GOT1 withdrawal. Targeting any of these pathways triggered ferroptosis, an oxidative, non-apoptotic, iron-dependent form of cell death in GOT1 knockdown cells. Mechanistically, GOT1 inhibition promoted a catabolic state and enhanced the availability of labile iron through autophagy and iron uptake. In sum, our study identifies a novel biochemical connection between GOT1, iron regulation, and ferroptosis, and suggests GOT1 plays a role in protecting PDA from metabolic stress.
2021-06-03 | GSE157830 | GEO
Project description:Ferroptosis is a unique iron-dependent form of non-apoptotic cell death characterized by devastating lipid peroxidation. Whilst growing evidence suggests that ferroptosis is a type of autophagy-dependent cell death, the underlying molecular mechanisms regulating ferroptosis are largely unknown. In this study, through an unbiased RNA-sequencing screening, we demonstrate the activation of a multi-faceted tumor-suppressor protein Par-4/PAWR during ferroptosis. Functional studies reveal that genetic depletion of Par-4 effectively blocks ferroptosis, whereas Par-4 overexpression sensitizes cells to undergo ferroptosis. More importantly, we have determined that Par-4-triggered ferroptosis is mechanistically driven by the autophagic machinery. Upregulation of Par-4 promotes activation of ferritinophagy (autophagic degradation of ferritin) via the nuclear receptor co-activator 4 (NCOA4), resulting in excessive release of free labile iron and, hence, enhanced lipid peroxidation and ferroptosis. Inhibition of Par-4 dramatically suppresses the NCOA4-mediated ferritinophagy signaling axis. Our results also establish that Par-4 activation positively correlates with reactive oxygen species (ROS) production, which is critical for ferritinophagy-mediated ferroptosis. Furthermore, Par-4 knockdown effectively blocked ferroptosis-mediated tumor suppression in the mouse xenograft models. Collectively, these findings reveal that Par-4 has a crucial role in ferroptosis, which could be further exploited for cancer therapy.
2024-05-24 | GSE267823 | GEO
Project description:Ferroptosis is a regulated form of necrotic cell death caused by an iron-dependent accumulation of oxidized phospholipids in cellular membranes, which culminates in plasma membrane rupture (PMR) and cell lysis. PMR is also a hallmark of other types of programmed necrosis, such as pyroptosis and necroptosis, where it is initiated by dedicated pore-forming cell death executors. Yet, whether ferroptosis-associated PMR is actively executed by a protein or driven by osmotic pressure remains unknown. Here, we investigated the role of ninjurin-1 (NINJ1), the recently identified executor of pyroptosis-associated PMR, in ferroptosis. We report that during ferroptosis NINJ1 oligomerizes and that Ninj1-deficiency protects macrophages and fibroblasts from ferroptosis-associated PMR. Mechanistically, we find that NINJ1 is dispensable for the early steps of ferroptosis, such as lipid peroxidation, channel-mediated calcium influx and cell swelling. By contrast, NINJ1 is required for early loss of plasma membrane integrity, an event that precedes complete PMR. Furthermore, NINJ1 mediates the release of cytosolic proteins and danger-associated molecular patterns (DAMPs) from ferroptotic cells, suggesting that targeting NINJ1 could be a therapeutic option to reduce ferroptosis-associated inflammation.
2024-02-15 | PXD047622 | Pride
Project description:Iron overload, characterized by accumulation of iron in tissues, induces a multiorgan toxicity whose mechanisms are not fully understood. Using cultured cell lines, Caenorhabditis elegans, and mice, we found that ferroptosis occurs in the context of iron-overload-mediated damage. Exogenous oleic acid protected against iron-overload-toxicity in cell culture and Caenorhabditis elegans by suppressing ferroptosis. In mice, oleic acid protected against FAC-induced liver lipid peroxidation and damage. Oleic acid changed the cellular lipid composition, characterized by decreased levels of polyunsaturated fatty acyl phospholipids and decreased levels of ether-linked phospholipids. The protective effect of oleic acid in cells was attenuated by GW6471 (a PPAR- antagonist), as well as in Caenorhabditis elegans lacking the nuclear hormone receptor NHR-49 (a PPAR- functional homologue). These results highlight ferroptosis as a driver of iron-overload-mediated damage, which is inhibited by oleic acid. This monounsaturated fatty acid represents a potential therapeutic approach to mitigating organ damage in iron overload individuals.
2023-10-02 | GSE243891 | GEO
Project description:Liver iron overload can induce hepatic expression of hepcidin and regulates iron metabolism. However, the mechanism of iron regulating iron metabolism remains known. Intracellular labile iron represents the nonferritin-bound, redox-active iron which is transitory and serves as a crossroad of cell iron metabolism. The role of intracellular labile iron played in iron metabolism has largely been elucidated. Here we show that intracellular labile iron of hepatocytes has dual function in iron metabolism. It can induce hepatocytes expressing hepcidin via ER stress induced transcription factors on the one hand, on the other hand stimulate BMP2 and BMP6 expression of liver sinusoidal endothelial cells (LSECs) though TNFα secreted by hepatocytes to further regulate iron metabolism. Blockade of TNFα could dysregulate the iron metabolism during iron overload. Our findings reveal the important role of intracellular labile iron in iron metabolism and represent a novel way to modulate iron metabolism during iron overload.
2023-05-03 | GSE186655 | GEO
Project description:While the importance of the iron-load of lipocalin-2 (Lcn-2) in promoting tumor progression is widely appreciated, underlying molecular mechanisms largely remain elusive. Considering its role as an iron-transporter, we aimed at clarifying iron-loaded, holo-Lcn-2 (hLcn-2)-dependent signaling pathways in affecting renal cancer cell viability. Applying RNA sequencing analysis in renal CAKI1 tumor cells to explore highly upregulated molecular signatures in response to hLcn-2, we identified a cluster of genes (SLC7A11, GCLM, GLS), which are implicated in regulating ferroptosis. Indeed, hLcn-2-stimulated cells are protected from erastin-induced ferroptosis. We also noticed a rapid increase in reactive oxygen species (ROS) with subsequent activation of the antioxidant Nrf2 pathway. However, knocking down Nrf2 by siRNA was not sufficient to induce erastin-dependent ferroptotic cell death in hLcn-2-stimulated tumor cells. In contrast, preventing oxidative stress through N-acetyl-L-cysteine (NAC) supple-mentation was still able to induce erastin-dependent ferroptotic cell death in hLcn-2-stimulated tumor cells. Besides an oxidative stress response, we noticed activation of the integrated stress response (ISR), shown by enhanced phosphorylation of eIF-2α and induction of ATF4 after hLcn-2 addition. ATF4 knockdown as well as inhibition of the ISR sensitized hLcn-2-treated renal tumor cells to ferroptosis, thus linking the ISR to pro-tumor characteristics of hLcn-2. Our study provides mechanistic details to better understand tumor pro-survival pathways initi-ated by iron-loaded Lcn-2.
2021-06-02 | GSE171939 | GEO
Project description:BTB and CNC homology 1 (BACH1) represses the expression of genes involved in the metabolism of iron, heme and reactive oxygen species and promotes metastasis of various cancers including pancreatic ductal adenocarcinoma (PDAC). Knockdown of Tank binding kinase 1 (TBK1) led to reductions of BACH1 mRNA and protein amounts in AsPC-1 human PDAC cells. Gene expression analysis of PDAC cells with knockdown of TBK1 or BACH1 suggested the involvement of TBK1 and BACH1 in the regulation of iron homeostasis. Ferritin was increased upon BACH1 knockdown in AsPC-1 cells. Cytometry analysis showed that AsPC-1 cells with BACH1 knockout or knockdown contained lower labile iron than control cells, suggesting that BACH1 increased labile iron by repressing the expression of ferritin genes.
2022-08-31 | GSE201307 | GEO
Project description:Iron-bound lipocalin-2 protects renal cell carcinoma from ferroptosis
| PRJNA721537 | ENA
Project description:Alterations of metabolic and biological processes occur in ferroptotic cells. We analyzed transcriptional responses of murine embryonic fibroblasts (MEFs) exposed to a ferroptosis inducer erastin. We found that a set of genes related to protection against oxidative stress was induced upon ferroptosis and Bach1 promoted ferroptosis by repressing a set of these genes involved in synthesis of glutathione or metabolism of intracellular labile iron. Our findings suggests that ferroptosis is programmed at transcriptional level and Bach1 works as a controller in setting a threshold of ferroptosis.
2019-11-15 | GSE131444 | GEO
Project description:Ferroptosis is a form of regulated cell death driven by the iron-dependent accumulation of oxidized polyunsaturated-fatty-acid-containing phospholipids (PUFA-PLs). Three key molecular features of ferroptosis are peroxidation of PUFA-PLs, accumulation of redox-active ferrous iron, and defective lipid peroxide repair (Dixon and Stockwell, 2019). However, there is currently no reliable way to selectively stain ferroptotic cells in tissue sections to characterize the extent of ferroptosis in animal models of disease and in patient tissue samples. We sought to address this gap by immunizing mice with membranes from lymphoma cells treated with the ferroptosis inducer piperazine erastin (PE), and screening ~4,750 of the resulting monoclonal antibodies generated for their ability to selectively detect cells undergoing ferroptosis. We found that one antibody, termed 3F3 Ferroptotic Membrane Antibody (3F3-FMA), was effective as a selective ferroptosis-staining reagent using immunofluorescence (IF). The antigen of 3F3-FMA was identified by immunoprecipitation and mass spectrometry as the human transferrin receptor 1 protein (TfR1), which imports iron from the extracellular environment into cells. We validated this finding with several additional anti-TfR1 antibodies, and compared them to other potential ferroptosis-detecting reagents via immunofluorescence staining, using fluorescence microscopy and flow cytometry. We found that anti-TfR1 and anti-malondialdehyde (MDA) adduct antibodies were effective at reliably staining ferroptotic tumor cells in numerous cell culture and tissue contexts. In summary, these findings suggest that anti-TfR1 antibodies can be used to selectively label cells undergoing ferroptosis.
2020-03-10 | PXD017425 | Pride