erastin and Neoplasms

The cystine/glutamate antiporter SLC7A11 (also commonly known as xCT) functions to import cystine for glutathione biosynthesis and antioxidant defense and is overexpressed in multiple human cancers. Recent studies revealed that SLC7A11 overexpression promotes tumor growth partly through suppressing ferroptosis, a form of regulated cell death induced by excessive lipid peroxidation. However, cancer cells with high expression of SLC7A11 (SLC7A11

Topics: Amino Acid Transport System y+; Antineoplastic Agents; Cystine; DNA Methylation; Ferroptosis; Gene Expression Regulation, Neoplastic; Glucose; Glutamine; Glutathione; Histones; Humans; Molecular Targeted Therapy; Neoplasms; Piperazines; Signal Transduction; Sorafenib; Sulfasalazine

The discovery of regulated cell death processes has enabled advances in cancer treatment. In the past decade, ferroptosis, an iron-dependent form of regulated cell death driven by excessive lipid peroxidation, has been implicated in the development and therapeutic responses of various types of tumours. Experimental reagents (such as erastin and RSL3), approved drugs (for example, sorafenib, sulfasalazine, statins and artemisinin), ionizing radiation and cytokines (such as IFNγ and TGFβ1) can induce ferroptosis and suppress tumour growth. However, ferroptotic damage can trigger inflammation-associated immunosuppression in the tumour microenvironment, thus favouring tumour growth. The extent to which ferroptosis affects tumour biology is unclear, although several studies have found important correlations between mutations in cancer-relevant genes (for example, RAS and TP53), in genes encoding proteins involved in stress response pathways (such as NFE2L2 signalling, autophagy and hypoxia) and the epithelial-to-mesenchymal transition, and responses to treatments that activate ferroptosis. Herein, we present the key molecular mechanisms of ferroptosis, describe the crosstalk between ferroptosis and tumour-associated signalling pathways, and discuss the potential applications of ferroptosis in the context of systemic therapy, radiotherapy and immunotherapy.

Topics: Cell Death; Ferroptosis; Humans; Interferon-gamma; Iron; Lipid Peroxidation; Neoplasms; Piperazines; Radiation, Ionizing

Cancer cells have been confirmed diverge significantly from normal cells on the metabolic properties. Energy production in cancer cells is abnormally dependent on the glycolysis pathway and other atypical metabolic characteristics such as increased fatty acid synthesis and increased rates of glutamine metabolism. Among these metabolic features of cancers, glutamine metabolism has been reported to be the main energy supply for the growth and viability of a potentially large subset of malignant tumors. In addition, the significance of glutamine metabolism in cancer cells derives from the ability of donate its nitrogen and carbon atoms for the synthesis of important biologically substances. During recent years, emerging evidences have proved the inhibitors targeting glutamine metabolism pathway could be efficient anticancer drugs. Therefore, in this review, we would briefly introduce the regulation of glutamine metabolism, and then summarize the recent advances of small molecule modulators targeting various nodes in glutamine signaling pathway. The current potential obstacles and future therapeutic perspectives in glutamine metabolism are also put forward in order to provide reference for the drug discovery of novel and potent glutamine metabolism modulators.

Topics: Animals; Antineoplastic Agents; Drug Discovery; Energy Metabolism; Glutamine; Humans; Neoplasms

Recently, it was demonstrated that some anti-cancer agents used mitochondrial voltage-dependent anion channels (VDAC1-3 isoforms) as their pharmacological target. VDACs are expressed more highly in cancer cells than normal cells; thus the VDAC-dependent cytotoxic agents can have cancer-selectivity. Furanonaphthoquinones (FNQs) induced caspase-dependent apoptosis via the production of NADH-dependent reactive oxygen species (ROS) by VDAC1. The ROS production and the anti-cancer activity of FNQs were increased by VDAC1 overexpression. Meanwhile, erastin induced RAS-RAF-MEK-dependent non-apoptotic cell death via VDAC2. On the other hand, VDACs were needed for transporting ATP to hexokinase (HK), which was highly expressed in cancer cells. We hypothesized that the high glycolysis might induce up-regulation of VDAC. In this review, we propose that VDACs are novel candidates for effective pharmacological targets of anti-cancer drugs.

Topics: Animals; Antineoplastic Agents; Apoptosis; Gene Expression Regulation, Neoplastic; Glycolysis; Humans; Mitochondrial Proteins; Neoplasm Proteins; Neoplasms; Oncogene Protein p21(ras); Piperazines; Protein Isoforms; raf Kinases; Reactive Oxygen Species; Voltage-Dependent Anion Channels

Chemical genetics has arisen as a tool for the discovery of pathways and proteins in mammalian systems. This approach, comprising small-molecule screening combined with biochemical and genomic target identification methods, enables one to assess which proteins are involved in regulating a particular phenotype. Applied to cell death, this strategy can reveal novel targets and pathways regulating the demise of mammalian cells. Numerous diseases have been linked to the loss of regulation of cell death. Defining the mechanisms governing cell death in these diseases might lead to the discovery of therapeutic agents and targets and provide a richer understanding of the mortality of living systems. Recent advances include the discovery of novel small molecules regulating cell death pathways -- necrostatin and erastin -- as well as the elucidation of the mechanism of death induced in cancer cells by the cytotoxic agent Apratoxin A.

Topics: Animals; Antineoplastic Agents; Cell Death; Cell Line, Tumor; Depsipeptides; Genetic Techniques; Genome; Humans; Imidazoles; Indoles; Neoplasms; Pharmaceutical Preparations; Phenotype; Piperazines; Proteins

Cancer stem cells (CSCs), enabled to self-renew, differentiate, and initiate the bulk tumor, are recognized as the culprit of treatment resistance, metastasis, and recurrence. Simultaneously eradicating CSCs and bulk cancer cells is crucial for successful cancer therapy. Herein, we reported that doxorubicin (Dox) and erastin co-loaded hydroxyethyl starch-polycaprolactone nanoparticles (DEPH NPs) eliminated CSCs and cancer cells by regulating redox status. We found that an excellently synergistic effect existed when Dox and erastin were co-delivered by DEPH NPs. Specifically, erastin could deplete intracellular glutathione (GSH), thereby inhibiting the efflux of intracellular Dox and boosting Dox-induced reactive oxygen species (ROS) to amplify redox imbalance and oxidative stress. The high ROS levels restrained CSCs self-renewal via downregulating Hedgehog pathways, promoted CSCs differentiation, and rendered differentiated cancer cells vulnerable to apoptosis. As such, DEPH NPs significantly eliminated not only cancer cells but more importantly CSCs, contributing to suppressed tumor growth, tumor-initiating capacity, and metastasis, in various tumor models of triple negative breast cancer. This study demonstrates that the combination of Dox and erastin is potent in elimination of both cancer cells and CSCs, and that DEPH NPs represent a promising treatment against CSCs-rich solid tumors.

Topics: Cell Line, Tumor; Doxorubicin; Hedgehog Proteins; Nanoparticles; Neoplasms; Reactive Oxygen Species; Starch

Microtubule targeting agents (MTAs) are used as clinically effective chemotherapies for cancer treatment but might be limited by the acquired or intrinsic resistance of cancer cells to apoptosis. The vulnerability of therapy-resistant cancers to ferroptosis provides an alternative way to overcome drug resistance. In this study, on the basis of the MTAs obtained in our previous studies, a series of MTAs were synthesized, and detailed structure-activity relationships were obtained through extensive molecular dynamics studies. Among them, a diphenylethene derivative, compound

Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Ferroptosis; Humans; Microtubules; Neoplasms; Stilbenes

Ferroptosis, a new form of programmed cell death, not only promotes the pathological process of various human diseases, but also regulates cancer progression. Current perspectives on the underlying mechanisms remain largely unknown. Herein, we report a member of the NEET protein family, CISD3, exerts a regulatory role in cancer progression and ferroptosis both in vivo and in vitro. Pan-cancer analysis from TCGA reveals that expression of CISD3 is generally elevated in various human cancers which are consequently associated with a higher hazard ratio and poorer overall survival. Moreover, knockdown of CISD3 significantly accelerates lipid peroxidation and accentuates free iron accumulation triggered by Xc

Topics: Animals; Cell Line, Tumor; Cell Survival; Cystine; Disease Progression; Ferroptosis; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Glutamine; Homeostasis; Humans; Iron; Iron-Sulfur Proteins; Lipid Peroxides; Mice, Nude; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Mitophagy; Neoplasms; Organophosphorus Compounds; Piperazines; Ubiquinone; Xenograft Model Antitumor Assays

Photodynamic therapy (PDT) is widely used in cancer treatment; however, several challenges compromise its efficiency. We propose a synergistic action between PDT and ferroptotic cell death. PDT acts as a source of reactive oxygen species for the Fenton reaction, which may reinforce ferroptosis induction and increase PDT efficacy in anticancer therapy.

Topics: Animals; Carbolines; Cell Line, Tumor; Chlorophyllides; Ferroptosis; Humans; Mice; Nanoparticle Drug Delivery System; Neoplasms; Photochemotherapy; Photosensitizing Agents; Piperazines; Reactive Oxygen Species; Sorafenib; Treatment Outcome

Sorafenib, a protein kinase inhibitor approved for the treatment of hepatocellular carcinoma and advanced renal cell carcinoma, has been repeatedly reported to induce ferroptosis by possibly involving inhibition of the cystine/glutamate antiporter, known as system x

Topics: Amino Acid Transport System y+; Animals; Antineoplastic Agents; Cell Line, Tumor; Drug Resistance, Neoplasm; Ferroptosis; HEK293 Cells; Humans; Mice; Neoplasms; Piperazines; Protein Kinase Inhibitors; Sorafenib; Sulfasalazine

Ferroptosis is a newly characterized form of regulated cell death mediated by iron-dependent accumulation of lipid reactive oxygen species and holds great potential for cancer therapy. However, the molecular mechanisms underlying ferroptosis remain largely elusive. In this study, we define an integrative role of DJ-1 in ferroptosis. Inhibition of DJ-1 potently enhances the sensitivity of tumor cells to ferroptosis inducers both in vitro and in vivo. Metabolic analysis and metabolite rescue assay reveal that DJ-1 depletion inhibits the transsulfuration pathway by disrupting the formation of the S-adenosyl homocysteine hydrolase tetramer and impairing its activity. Consequently, more ferroptosis is induced when homocysteine generation is decreased, which might be the only source of glutathione biosynthesis when cystine uptake is blocked. Thus, our findings show that DJ-1 determines the response of cancer cells to ferroptosis, and highlight a candidate therapeutic target to potentially improve the effect of ferroptosis-based antitumor therapy.

Topics: Adenosylhomocysteinase; Animals; Antineoplastic Agents; Cell Line, Tumor; Female; Ferroptosis; Fibroblasts; Glutathione; HEK293 Cells; Homocysteine; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Neoplasms; Piperazines; Primary Cell Culture; Protein Deglycase DJ-1; Protein Multimerization; RNA, Small Interfering; Xenograft Model Antitumor Assays

Ferroptosis is an iron-dependent form of regulated cell death. In this study, a ratiometric fluorescent probe, gold carbon dots (GCDs) consisting of carbon skeleton and gold nanoclusters, was used for in situ imaging to monitor redox status in biothiols (glutathione and cysteine) and ferric metabolism of cancer cells in ferroptosis. The as-prepared GCDs can selectively respond to biothiols, interestingly, the fluorescence may be switched to sense ferric ions without interference by biothiols under proper conditions. The robust GCDs-probe exhibits excellent photobleaching resistance and can reversibly respond to intracellular biothiols/ferric ion with high temporal resolution. The 8 h real-time imaging of living cells was employed to track the fluctuation of biothiols, showing the change of redox status in ferroptosis. In addition, release of ferric ions in cells was monitored. The real-time imaging of depletion of biothiols and release of ferric ion in cells indicates the GCDs-probe can monitor how the ferroptosis regulates redox status in biothiols and ferric metabolism.

Topics: Carbon; Cell Line, Tumor; Cysteine; Ferroptosis; Fluorescent Dyes; Glutathione; Gold; Humans; Iron; Light; Metal Nanoparticles; Microscopy, Confocal; Microscopy, Fluorescence; Neoplasms; Oxidation-Reduction; Piperazines; Quantum Dots

Ferroptosis is a non-apoptotic form of cell death characterized by the iron-dependent lipid peroxidation and is implicated in several human pathologies, such as tissue ischemia, neurodegeneration, and cancer. Ferroptosis appears to be high cell-context dependent and the regulation of ferroptosis by physiological or pathological conditions are unclear. Here, we report that tumor-derived IDH1 mutation sensitizes cells to ferroptosis. Deletion of the mutant IDH1 allele in IDH1 heterozygous tumor cells or pharmacological inhibition of mutant IDH1 to produce the oncometabolite D-2-hydroxyglutarate (D-2-HG) confers resistance to erastin-induced ferroptosis. Conversely, ectopic expression of mutant IDH1 or treatment of cells with cell-permeable D-2-HG promotes the accumulation of lipid reactive oxygen species (ROS) and subsequently ferroptosis. Mechanistically, mutant IDH1 reduces the protein level of the glutathione peroxidase 4 (GPX4), a key enzyme in removing lipid ROS and ferroptosis, and promotes depletion of glutathione. Our results uncover a new role of mutant IDH1 and 2-HG in ferroptosis.

Topics: Alleles; Cell Line, Tumor; Ferroptosis; Glutarates; Humans; Iron; Ischemia; Isocitrate Dehydrogenase; Lipid Peroxidation; Neoplasms; Nerve Degeneration; Piperazines; Reactive Oxygen Species

Damage-associated molecular pattern molecules (DAMPs) are endogenous danger signals that alert the innate immune system and shape the inflammation response to cell death. However, the release and activity of DAMPs in ferroptosis, a recently identified form of regulated necrosis characterized by iron overload and lipid peroxidation, still remain poorly understood. Here, we demonstrate that HMGB1 is a DAMP released by ferroptotic cells in an autophagy-dependent manner. Both type I and II ferroptosis activators, including erastin, sorafenib, RSL3, and FIN56, induce HMGB1 release in cancer and noncancer cells. In contrast, genetic ablation (using ATG5

Topics: Animals; Autophagy; Carbolines; Cell Death; Cell Line, Tumor; Chloroquine; Ferritins; Fibroblasts; HMGB1 Protein; Humans; Immunity, Innate; Inflammation; Iron Overload; Lipid Peroxidation; Macrolides; Mice; Neoplasms; Oximes; Piperazines; Sorafenib; Sulfonamides; Toll-Like Receptor 4

SLC7A11 (or xCT) imports extracellular cystine into cells to promote glutathione synthesis, thus inhibiting ferroptosis. SLC7A11 expression is tightly controlled in normal cells and its dysregulation results in aberrant expression of SLC7A11 in human cancers. We recently discovered that tumor suppressor BAP1, a H2A deubiquitinase, represses SLC7A11 expression by reducing H2A ubiquitination (H2Aub) on the SLC7A11 promoter. BAP1 inactivation in cancer cells leads to SLC7A11 de-repression, ferroptosis resistance, and tumor development. Here we show that BAP1 promotes ferroptosis induced by class I ferroptosis inducer (FIN) erastin but not by class II FIN RSL3, further supporting that BAP1 regulates ferroptosis through SLC7A11. In addition, we studied how BAP1 coordinates with other transcription factors to regulate SLC7A11 expression and show that BAP1-mediated SLC7A11 repression does not require NRF2 and ATF4 transcription factors. Finally, we show that, while BAP1 decreases whereas PRC1 (a major H2Aub ubiquitin ligase) increases H2Aub binding on the SLC7A11 promoter, both BAP1 and PRC1 represses SLC7A11 expression, suggesting that a dynamic regulation of H2Aub is important for SLC7A11 repression. Together, our data provide additional insights on epigenetic regulation of SLC7A11 expression in cancer cells.

Topics: Activating Transcription Factor 4; Amino Acid Transport System y+; Cell Cycle Proteins; Cell Line, Tumor; Cell Survival; Ferroptosis; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; HEK293 Cells; Histones; Humans; Neoplasms; NF-E2-Related Factor 2; Piperazines; Promoter Regions, Genetic; Transfection; Tumor Suppressor Proteins; Ubiquitin Thiolesterase; Ubiquitination

Induction of ferroptosis has emerged as a potential cancer therapeutic approach. In this issue of Cell Chemical Biology, Zhang et al. (2019) demonstrate the anticancer efficacy and safety of the ferroptosis inducer imidazole ketone erastin (IKE) in a xenograft model by using a nanoparticle-based delivery system.

Topics: Animals; Ferroptosis; Imidazoles; Ketones; Lymphoma; Mice; Nanoparticles; Neoplasms; Piperazines

Ferroptosis is a new mode of regulated cell death, which is completely distinct from other cell death modes based on morphological, biochemical, and genetic criteria. This study evaluated the therapeutic role of ferroptosis in classic chemotherapy drugs, including the underlying mechanism.. Cell viabilitywas detected by using the methylthiazoltetrazlium dye uptake method. RNAiwas used to knockout iron-responsive element binding protein 2, and polymerase chain reaction, western blot was used to evaluate the efficiency. Intracellular reduced glutathione level and glutathione peroxidases activitywere determined by related assay kit. Intracellularreactive oxygen species levelswere determined by flowcytometry. Electron microscopywas used to observe ultrastructure changes in cell.. Among five chemotherapeutic drugs screened in this study, cisplatin was found to be an inducer for both ferroptosis and apoptosis in A549 and HCT116 cells. The depletion of reduced glutathione caused by cisplatin and the inactivation of glutathione peroxidase played the vital role in the underlying mechanism. Besides, combination therapy of cisplatin and erastin showed significant synergistic effect on their anti-tumor activity.. Ferroptosis had great potential to become a new approach in anti-tumor therapies and make up for some classic drugs, which open up a new way for their utility in clinic.

Topics: A549 Cells; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Cell Death; Cisplatin; Colorectal Neoplasms; Fibrosarcoma; Glutathione Peroxidase; HCT116 Cells; Humans; Lung Neoplasms; Neoplasms; Piperazines

In Warburg metabolism, suppression of mitochondrial metabolism contributes to a low cytosolic ATP/ADP ratio favoring enhanced aerobic glycolysis. Flux of metabolites across the mitochondrial outer membrane occurs through voltage-dependent anion channels (VDAC). In cancer cells, free dimeric tubulin induces VDAC closure and dynamically regulates mitochondrial membrane potential (ΔΨ). Erastin, a small molecule that binds to VDAC, antagonizes the inhibitory effect of tubulin on VDAC and hyperpolarizes mitochondria in intact cells. Here, our aim was to identify novel compounds from the ChemBridge DIVERSet library that block the inhibitory effect of tubulin on ΔΨ using cell-based screening. HCC4006 cells were treated with nocodazole (NCZ) to increase free tubulin and decrease ΔΨ in the presence or absence of library compounds. Tetramethylrhodamine methylester (TMRM) fluorescence was assessed by high-content imaging to determine changes in ΔΨ. Compounds were considered positive if ΔΨ increased in the presence of NCZ. Using confocal microscopy, we identified and validated six lead molecules that antagonized the depolarizing effect of NCZ. Lead compounds and erastin did not promote microtubule stabilization, so changes in ΔΨ were independent of tubulin dynamics. The most potent lead compound also decreased lactate formation. These novel small molecules represent a potential new class of anti-Warburg drugs.

Topics: Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Energy Metabolism; High-Throughput Screening Assays; Humans; Lactates; Membrane Potential, Mitochondrial; Mitochondria; Molecular Imaging; Molecular Structure; Neoplasms; Nocodazole; Piperazines; Protein Multimerization; Tubulin; Voltage-Dependent Anion Channels; Workflow

System x

Topics: Cell Death; Cell Line, Tumor; Cisplatin; Glutathione; Humans; Necrosis; Neoplasms; Piperazines

Ferroptosis is a form of nonapoptotic cell death for which key regulators remain unknown. We sought a common mediator for the lethality of 12 ferroptosis-inducing small molecules. We used targeted metabolomic profiling to discover that depletion of glutathione causes inactivation of glutathione peroxidases (GPXs) in response to one class of compounds and a chemoproteomics strategy to discover that GPX4 is directly inhibited by a second class of compounds. GPX4 overexpression and knockdown modulated the lethality of 12 ferroptosis inducers, but not of 11 compounds with other lethal mechanisms. In addition, two representative ferroptosis inducers prevented tumor growth in xenograft mouse tumor models. Sensitivity profiling in 177 cancer cell lines revealed that diffuse large B cell lymphomas and renal cell carcinomas are particularly susceptible to GPX4-regulated ferroptosis. Thus, GPX4 is an essential regulator of ferroptotic cancer cell death.

Topics: Animals; Carbolines; Carcinoma, Renal Cell; Cell Death; Cell Line, Tumor; Gene Knockdown Techniques; Glutathione; Glutathione Peroxidase; Heterografts; Humans; Lymphoma, B-Cell; Mice; Neoplasm Transplantation; Neoplasms; Phospholipid Hydroperoxide Glutathione Peroxidase; Piperazines

Ferroptosis is a recently identified form of regulated necrosis that can be experimentally induced in cancer cells with the chemical inducer erastin. Recently, we identified sorafenib, an inhibitor of oncogenic kinases, as an inducer of ferroptosis in hepatocellular carcinoma cells. Whether sorafenib is able to exert its ferroptotic activity in cancer cells originating from other tissues is presently unclear.. We compared the levels of ferroptosis induced by sorafenib with those induced by the reference compound erastin in a panel of ten human cell lines originating from various tissues.. Sorafenib induced ferroptosis in different cancer cell lines. We found a positive correlation between the ferroptotic potency of sorafenib and erastin. Compared to other kinase inhibitors, sorafenib is the only drug that displays ferroptotic efficacy.. The findings establish sorafenib as the first clinically-approved anticancer drug that can induce ferroptosis.

Topics: Apoptosis; Biomarkers, Tumor; Blotting, Western; Cell Proliferation; Humans; L-Lactate Dehydrogenase; Necrosis; Neoplasms; Niacinamide; Phenylurea Compounds; Piperazines; Protein Kinase Inhibitors; Sorafenib; Tumor Cells, Cultured

A series of Pictet-Spengler condensation derivatives (tetrahydro-β-carbolines) was designed, synthesized and evaluated for lethality against a panel of seven cancer cell lines. Seven compounds (2a, 13, 20, 21, 27, 29 and 34) showed lethality in at least five cell lines. Among these, compound 27 showed a unique selectivity towards oncogenic-RAS expressing BJ-TERT/LT/ST/RAS(V12) tumor cells, compared to non-transformed BJ-TERT cells. Further investigation revealed that 27 induces cell death without activation of caspases. This represents a useful new probe of non-apoptotic cell death and oncogenic-RAS synthetic lethality.

Topics: Antineoplastic Agents; Carbolines; Cell Death; Cell Line, Tumor; Cell Survival; Drug Design; Gene Expression Regulation, Neoplastic; Genes, ras; Humans; Neoplasms

Nonapoptotic forms of cell death may facilitate the selective elimination of some tumor cells or be activated in specific pathological states. The oncogenic RAS-selective lethal small molecule erastin triggers a unique iron-dependent form of nonapoptotic cell death that we term ferroptosis. Ferroptosis is dependent upon intracellular iron, but not other metals, and is morphologically, biochemically, and genetically distinct from apoptosis, necrosis, and autophagy. We identify the small molecule ferrostatin-1 as a potent inhibitor of ferroptosis in cancer cells and glutamate-induced cell death in organotypic rat brain slices, suggesting similarities between these two processes. Indeed, erastin, like glutamate, inhibits cystine uptake by the cystine/glutamate antiporter (system x(c)(-)), creating a void in the antioxidant defenses of the cell and ultimately leading to iron-dependent, oxidative death. Thus, activation of ferroptosis results in the nonapoptotic destruction of certain cancer cells, whereas inhibition of this process may protect organisms from neurodegeneration.

Topics: Animals; Cell Death; Cyclohexylamines; Fibroblasts; Glutamic Acid; Hippocampus; Humans; In Vitro Techniques; Iron; Lipid Metabolism; Neoplasms; Phenylenediamines; Piperazines; Rats; Reactive Oxygen Species

We screened small molecules to identify two compounds, which we named RSL3 and RSL5, that have increased lethality in the presence of oncogenic RAS. Counter screening with biologically active compounds defined aspects of the mechanism of action for RSL3 and RSL5, such as a nonapoptotic, MEK-dependent, and iron-dependent oxidative cell death. Erastin, a previously reported compound with RAS-selective lethality, showed similar properties. RNA interference experiments targeting voltage-dependent anion channel 3 (VDAC3), a target of erastin, demonstrated that RSL5 is a scaffold that acts through VDACs to activate the observed pathway. RSL3 activated a similar death mechanism but in a VDAC-independent manner. We found that cells transformed with oncogenic RAS have increased iron content relative to their normal cell counterparts through upregulation of transferrin receptor 1 and downregulation of ferritin heavy chain 1 and ferritin light chain.

Topics: Apoptosis; Cell Death; Cell Line, Tumor; Drug Evaluation, Preclinical; Gene Expression Regulation, Neoplastic; Humans; Iron; Mutation; Neoplasms; Piperazines; Proto-Oncogene Proteins p21(ras); Small Molecule Libraries; Substrate Specificity; Voltage-Dependent Anion Channels