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Stockwell, B. R.

Publications and source records attributed to Stockwell, B. R..

11 recordsLinked to original sources

Hydroperoxy-lipids Are Essential Yet Insufficient For Execution Of Ferroptosis

Cells with irreparable redox disbalance in membranes trigger a program of regulated death - ferroptosis. 15-lipoxygenase (LOX)-catalyzed accumulation of hydroperoxy-phosphatidyl-ethanolamines (HOO-PEs) has been associated with the execution of ferroptosis; yet, experimental proof of their sufficiency is lacking. Using the Fe-independent hydrophobic radical initiator, 2,2'-azobis(2,4-dimethyl)-valeronitrile (AMVN), we demonstrate that the accumulation of hydroperoxy-phospholipids (HOO-PLs) is necessary, but insufficient for driving ferroptosis. We further show that Fe-catalyzed decomposition of HOO-PLs into radical intermediates and oxidatively truncated (OxTr) electrophilic species, as well as the formation of protein adducts with OxTr electrophilic species are required for the completion of the ferroptotic program. Consequently, three types of agents - inhibitors of LOXs and other enzymatic generators of HOO-PLs, radical scavengers, and small-molecule nucleophiles - acting at different stages of lipid peroxidation during the ferroptotic program represent effective and specific ferroptosis regulators and potential therapeutic remedies.

biochemistry↗

miR-940 suppresses ferroptosis by controlling expression of key regulatory genes

Ferroptosis is a form of regulated cell death that is characterized by iron-dependent lipid peroxidation. This process is regulated by specific metabolites, the lipid composition of the cells, redox-active iron, and antioxidant mechanisms. Although numerous regulators have been identified over the past decade, exploring other mechanisms, particularly from non-coding genomic regions, can build a thorough understanding of the multifaceted regulatory processes underlying ferroptosis. MicroRNAs (miRNAs) play a crucial role in gene regulation and cellular functions. Through a CRISPR KO screen, we identified miR-940 as a negative regulator of ferroptosis. Overexpression of miR-940 in several cell lines consistently suppressed ferroptosis induced by system xc- inhibition. Notably, multiple cancer patient cohorts with elevated miR-940 levels exhibit reduced survival. Integrated bioinformatic, transcriptomic, and proteomic analyses revealed that miR-940 decreases the expression of ACSL4, LPCAT3, DMT1, and NCOA4, and simultaneously increases levels of GPX4. Pharmacological inhibition of GPX4 attenuated the protective effect of miR-940, indicating that its primary anti-ferroptotic activity is mediated through GPX4. Overall, this gene rewiring is associated with reduced levels of redox-active iron and diminished lipid peroxidation, consistent with ferroptosis suppression. These findings suggest that miR-940 coordinates ferroptosis inhibition, which presents a novel regulatory layer for therapeutic exploration in susceptible cancers.

cell biology↗

Dual pathway regulation of castration response and ferroptosis in the prostate epithelium

Understanding how sex hormones maintain tissue integrity--and how their disruption can promote cancer--is a central question in biology. In the prostate, androgen signaling is crucial for development, homeostasis, and cancer, yet the molecular mechanisms underlying tissue regression after androgen-deprivation have remained unknown. Here we show that castration induces epithelial regression via ferroptosis in the normal mouse and human prostate, as well as in prostate tumors. Using in vivo analyses in genetically-engineered mice, supported by validation in human organotypic cultures, we demonstrate that androgen receptor (AR) signaling controls castration response through two distinct pathways: an intrinsic luminal epithelial pathway regulated by the prostate-specific transcription factor NKX3.1, and an extrinsic stromal signal mediated by the secreted factor pleiotrophin (PTN). Together, these AR signaling pathways coordinately regulate biosynthesis of monounsaturated fatty acid (MUFA) phospholipids and GPX4 expression to suppress prostate epithelial ferroptosis. Our findings reveal a sex hormone-regulated ferroptotic program that governs tissue homeostasis and suggest that ferroptosis induction could represent a new therapeutic strategy for prostate cancer.

developmental biology↗

LIMD1 Loss Confers a GPX4-Dependent Cell State in Lung Cancer

LIMD1 (LIM domains containing 1) is a bona-fide tumour suppressor gene frequently lost during the early stages of non-small cell lung cancer (NSCLC) development, resulting in a worse outcome for LIMD1-deficient patients. LIMD1 deficiency is present in approximately 50% of NSCLC cases, representing at least 21,000 patients in the United Kingdom and 1.2 million worldwide. During cancer progression, cells can accumulate genetic changes that render them more dependent on certain genes for their survival. By performing CRISPR-Cas9 dropout screens, we identified GPX4 as a novel vulnerability in LIMD1 deficient LUAD cells. By targeting GPX4 using RNA interference (RNAi) and pharmacological intervention in our isogenic LUAD lines along with a non-transformed lung cell line, we validated GPX4 as a novel dependency in LIMD1 deficient cells. GPX4 is a key defence mechanism against ferroptosis, an iron-dependent form of regulated cell death. This state of increased ferroptosis susceptibility upon LIMD1 loss is due to increased basal reactive oxygen species levels and lipid peroxidation. Importantly, targeting GPX4 with ferroptosis inducing agents in NSCLC patients with LIMD1 loss may represent a novel therapeutic strategy.

cancer biology↗

Ferroptosis regulates hemolysis in stored murine and human red blood cells

Red blood cell (RBC) metabolism regulates hemolysis during aging in vivo and in the blood bank. Here, we leveraged a diversity outbred mouse population to map the genetic drivers of fresh/stored RBC metabolism and extravascular hemolysis upon storage and transfusion in 350 mice. We identify the ferrireductase Steap3 as a critical regulator of a ferroptosis-like process of lipid peroxidation. Steap3 polymorphisms were associated with RBC iron content, in vitro hemolysis, and in vivo extravascular hemolysis both in mice and 13,091 blood donors from the Recipient Epidemiology and Donor evaluation Study. Using metabolite Quantitative Trait Loci analyses, we identified a network of gene products (FADS1/2, EPHX2 and LPCAT3) - enriched in donors of African descent - associated with oxylipin metabolism in stored human RBCs and related to Steap3 or its transcriptional regulator, the tumor protein TP53. Genetic variants were associated with lower in vivo hemolysis in thousands of single-unit transfusion recipients. HighlightsO_LISteap3 regulates lipid peroxidation and extravascular hemolysis in 350 diversity outbred mice C_LIO_LISteap3 SNPs are linked to RBC iron, hemolysis, vesiculation in 13,091 blood donors C_LIO_LImQTL analyses of oxylipins identified ferroptosis-related gene products FADS1/2, EPHX2, LPCAT3 C_LIO_LIFerroptosis markers are linked to hemoglobin increments in transfusion recipients C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/598512v1_ufig1.gif" ALT="Figure 1"> View larger version (117K): org.highwire.dtl.DTLVardef@150fec2org.highwire.dtl.DTLVardef@859c43org.highwire.dtl.DTLVardef@1d60156org.highwire.dtl.DTLVardef@f1b91e_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Suppression of ferroptosis by vitamin A or antioxidants is essential for neuronal development

Development of functional neurons is a complex orchestration of several signaling pathways controlling cell proliferation, differentiation, and homeostasis1. However, details about the involved factors are not fully understood. The balance of antioxidants and vitamins is important for neuronal survival, synaptic plasticity, and early neuronal development; thus, we hypothesized that ferroptosis--a lipid peroxidation dependent cell death modality that is inhibited by antioxidanats2,3--needs to be suppressed to gain neurons. Our study shows that removal of antioxidants diminishes neuronal development and laminar organization of cortical organoids. Intriguingly, impaired neuronal development in conditions lacking antioxidants can be fully restored when ferroptosis is specifically inhibited by ferrostatin-1, or neuronal differentiation occurs in the presence of sufficient amounts of vitamin A. Mechanistically, vitamin A activates the heterodimeric nuclear receptor complex Retinoic Acid Receptor (RAR)/Retinoid X Receptor (RXR)4, which upregulates expression of the ferroptosis regulators GPX4, FSP1, GCH1, and ACSL3, amongst others. Therefore, our study reveals that above a certain threshold, vitamin A increases expression of essential cellular gatekeepers of lipid peroxidation. This study uncovers a critical process during early neuronal development, where suppression of ferroptosis by radical-trapping antioxidants or vitamin A is required to obtain maturing neurons and proper laminar organization in cortical organoids.

cell biology↗

A cell state specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma

Glioma cells hijack developmental transcriptional programs to control cell state. During neural development, lineage trajectories rely on specialized metabolic pathways. However, the link between tumor cell state and metabolic programs is poorly understood in glioma. Here we uncover a glioma cell state-specific metabolic liability that can be leveraged therapeutically. To model cell state diversity, we generated genetically engineered murine gliomas, induced by deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling cellular fate. N1IC tumors harbored quiescent astrocyte-like transformed cell states while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. N1IC cells exhibit distinct metabolic alterations, with mitochondrial uncoupling and increased ROS production rendering them more sensitive to inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Importantly, treating patient-derived organotypic slices with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles.

cancer biology↗

Multimodal mass spectrometry imaging reveals single-cell metabolic states in mammalian liver

We have developed a powerful workflow to imaging endogenous metabolism in single cells on frozen tissue, allowing us to discover new cell subtypes in human liver. Performing spatially integrated multiomics in single cells within tissues is at the leading frontier in biology but has been prevented by technological challenges. We developed a critical new technology, cryogenic water cluster ion beam secondary ion mass spectrometry imaging ((H2O)n>28K-GCIB-SIMS)) at 1 {micro}m single-cell resolution. This allowed us to perform multi-modal mass spectrometry imaging (MSI) to detect metabolites, lipids, and proteins in single cells within functional liver zones and diverse cell types in the native tissue state. Our workflow utilizes the desorption electrospray ionization (DESI) mass spectrometry imaging (MSI) to build a reference map of metabolic heterogeneity and zonation across liver functional units. Then cryogenic (H2O)n>28K-GCIB-SIMS and C60-SIMS integrated metabolomics, lipidomic and proteomics, - characterizing the metabolic state in single cells on the same tissue section. We found for the first time that lipids and metabolites can classify liver metabolic zones and liver cell types beyond histological and protein-marker annotation. This provides a multi-modal workflow to define single-cell states in normal physiology and disease in mammalian tissue.

cell biology↗

A simplified cell-based assay to identify coronavirus 3CL protease inhibitors

We describe a mammalian cell-based assay capable of identifying coronavirus 3CL protease (3CLpro) inhibitors without requiring the use of live virus. By enabling the facile testing of compounds across a range of coronavirus 3CLpro enzymes, including the one from SARS-CoV-2, we are able to quickly identify compounds with broad or narrow spectra of activity. We further demonstrate the utility of our approach by performing a curated compound screen along with structure-activity profiling of a series of small molecules to identify compounds with antiviral activity. Throughout these studies, we observed concordance between data emerging from this assay and from live virus assays. By democratizing the testing of 3CL inhibitors to enable screening in the majority of laboratories rather than the few with extensive biosafety infrastructure, we hope to expedite the search for coronavirus 3CL protease inhibitors, to address the current epidemic and future ones that will inevitably arise.

microbiology↗

Lead compounds for the development of SARS-CoV-2 3CL protease inhibitors

We report the identification of three structurally diverse compounds - compound 4, GC376, and MAC-5576 - as inhibitors of the SARS-CoV-2 3CL protease. Structures of each of these compounds in complex with the protease revealed strategies for further development, as well as general principles for designing SARS-CoV-2 3CL protease inhibitors. These compounds may therefore serve as leads for the basis of building effective SARS-CoV-2 3CL protease inhibitors.

microbiology↗

Induction of pancreatic tumor-selective ferroptosis through modulation of cystine import

Pancreatic ductal adenocarcinoma (PDA) is the third-leading cause of cancer mortality in the US and is highly resistant to classical, targeted, and immune therapies. We show that human PDA cells are dependent on the provision of exogenous cystine to avert a catastrophic accumulation of lipid reactive oxygen species (ROS) that, left unchecked, leads to ferroptotic cell death, both in vitro and in vivo. Using a dual-recombinase genetically engineered model, we found that acute deletion of Slc7a11 led to tumor-selective ferroptosis, tumor stabilizations/regressions, and extended overall survival. The mechanism of ferroptosis induction in PDA cells required the concerted depletion of both glutathione and coenzyme A, highlighting a novel branch of ferroptosis-relevant metabolism. Finally, we found that cystine depletion in vivo using the pre-IND agent cyst(e)inase phenocopied Slc7a11 deletion, inducing tumor-selective ferroptosis and disease stabilizations/regressions in the well-validated KPC model of PDA.\n\nOne Sentence SummaryGenetic and pharmacological targeting of cystine import induces pancreatic cancer-selective ferroptosis in vivo.

cancer biology↗