erastin and Melanoma

Ferroptosis is a newly defined form of regulated cell death characterized by the iron-dependent accumulation of lipid hydroperoxides. Erastin, the ferroptosis activator, binds to voltage-dependent anion channels VDAC2 and VDCA3, but treatment with erastin can result in the degradation of the channels. Here, the authors show that Nedd4 is induced following erastin treatment, which leads to the ubiquitination and subsequent degradation of the channels. Depletion of Nedd4 limits the protein degradation of VDAC2/3, which increases the sensitivity of cancer cells to erastin. By understanding the molecular mechanism of erastin-induced cellular resistance, we can discover how cells adapt to new molecules to maintain homeostasis. Furthermore, erastin-induced resistance mediated by FOXM1-Nedd4-VDAC2/3 negative feedback loop provides an initial framework for creating avenues to overcome the drug resistance of ferroptosis activators.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Drug Resistance, Neoplasm; Female; Ferroptosis; Forkhead Box Protein M1; Humans; Melanoma; Mice, Nude; Mitochondrial Membrane Transport Proteins; Nedd4 Ubiquitin Protein Ligases; Piperazines; Ubiquitination; Voltage-Dependent Anion Channel 2; Voltage-Dependent Anion Channels; Xenograft Model Antitumor Assays

The incidence of melanoma is increasing over the years with a still poor prognosis and the lack of a cure able to guarantee an adequate survival of patients. Although the new immuno-based coupled to target therapeutic strategy is encouraging, the appearance of targeted/cross-resistance and/or side effects such as autoimmune disorders could limit its clinical use. Alternative therapeutic strategies are therefore urgently needed to efficiently kill melanoma cells. Ferroptosis induction and execution were evaluated in metastasis-derived wild-type and oncogenic BRAF melanoma cells, and the process responsible for the resistance has been dissected at molecular level. Although efficiently induced in all cells, in an oncogenic BRAF- and ER stress-independent way, most cells were resistant to ferroptosis execution. At molecular level we found that: resistant cells efficiently activate NRF2 which in turn upregulates the early ferroptotic marker CHAC1, in an ER stress-independent manner, and the aldo-keto reductases AKR1C1 ÷ 3 which degrades the 12/15-LOX-generated lipid peroxides thus resulting in ferroptotic cell death resistance. However, inhibiting AKRs activity/expression completely resensitizes resistant melanoma cells to ferroptosis execution. Finally, we found that the ferroptotic susceptibility associated with the differentiation of melanoma cells cannot be applied to metastatic-derived cells, due to the EMT-associated gene expression reprogramming process. However, we identified SCL7A11 as a valuable marker to predict the susceptibility of metastatic melanoma cells to ferroptosis. Our results identify the use of pro-ferroptotic drugs coupled to AKRs inhibitors as a new valuable strategy to efficiently kill human skin melanoma cells.

Topics: Aldo-Keto Reductases; Arachidonate 15-Lipoxygenase; Biomarkers, Tumor; Cell Differentiation; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum Stress; Enzyme Inhibitors; Ferroptosis; gamma-Glutamylcyclotransferase; Gene Expression Regulation, Neoplastic; Humans; Lipid Peroxides; Melanoma; Neoplasm Metastasis; NF-E2-Related Factor 2; Oncogenes; Piperazines; Proto-Oncogene Proteins B-raf; Up-Regulation

Topics: Cell Line, Tumor; Cell Proliferation; DNA Damage; Ferroptosis; Genes, p53; Humans; Melanoma; Oxidative Stress; Piperazines

Ferroptosis is a regulated form of cell death driven by small molecules or conditions that induce lipid-based reactive oxygen species (ROS) accumulation. This form of iron-dependent cell death is morphologically and genetically distinct from apoptosis, necroptosis, and autophagy. miRNAs are known to play crucial roles in diverse fundamental biological processes. However, to date no study has reported miRNA-mediated regulation of ferroptosis. Here we show that miR-137 negatively regulates ferroptosis by directly targeting glutamine transporter SLC1A5 in melanoma cells. Ectopic expression of miR-137 suppressed SLC1A5, resulting in decreased glutamine uptake and malondialdehyde (MDA) accumulation. Meanwhile, antagomir-mediated inactivation of endogenous miR-137 increased the sensitivity of melanoma cells to erastin- and RSL3-induced ferroptosis. Importantly, knockdown of miR-137 increased the antitumor activity of erastin by enhancing ferroptosis both in vitro and in vivo. Collectively, these data indicate that miR-137 plays a novel and indispensable role in ferroptosis by inhibiting glutaminolysis and suggest a potential therapeutic approach for melanoma.

Topics: 3' Untranslated Regions; Amino Acid Transport System ASC; Animals; Antagomirs; Apoptosis; Cell Line, Tumor; Cyclohexylamines; Ferrous Compounds; Glutamine; Humans; Lipid Peroxidation; Malondialdehyde; Melanoma; Mice; Mice, Nude; MicroRNAs; Minor Histocompatibility Antigens; Phenylenediamines; Piperazines; Reactive Oxygen Species; RNA Interference; RNA, Small Interfering

Malignant transformation can result in melanoma cells that resemble different stages of their embryonic development. Our gene expression analysis of human melanoma cell lines and patient tumors revealed that melanoma follows a two-dimensional differentiation trajectory that can be subclassified into four progressive subtypes. This differentiation model is associated with subtype-specific sensitivity to iron-dependent oxidative stress and cell death known as ferroptosis. Receptor tyrosine kinase-mediated resistance to mitogen-activated protein kinase targeted therapies and activation of the inflammatory signaling associated with immune therapy involves transitions along this differentiation trajectory, which lead to increased sensitivity to ferroptosis. Therefore, ferroptosis-inducing drugs present an orthogonal therapeutic approach to target the differentiation plasticity of melanoma cells to increase the efficacy of targeted and immune therapies.

Topics: Cell Dedifferentiation; Cell Line, Tumor; Cell Survival; DNA Methylation; Drug Resistance, Neoplasm; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; Humans; Iron; Melanoma; Oxidative Stress; Piperazines; Signal Transduction; Vemurafenib

Ferroptosis is a recently recognized form of regulated cell death driven by lipid-based reactive oxygen species (ROS) accumulation. However, the molecular mechanisms of ferroptosis regulation are still largely unknown. Here we identified a novel miRNA, miR-9, as an important regulator of ferroptosis by directly targeting GOT1 in melanoma cells. Overexpression of miR-9 suppressed GOT1 by directly binding to its 3'-UTR, which subsequently reduced erastin- and RSL3-induced ferroptosis. Conversely, suppression of miR-9 increased the sensitivity of melanoma cells to erastin and RSL3. Importantly, anti-miR-9 mediated lipid ROS accumulation and ferroptotic cell death could be abrogated by inhibiting glutaminolysis process. Taken together, our findings demonstrate that miR-9 regulates ferroptosis by targeting GOT1 in melanoma cells, illustrating the important role of miRNA in ferroptosis.

Topics: 3' Untranslated Regions; Aspartate Aminotransferase, Cytoplasmic; Carbolines; Cell Line, Tumor; Cell Survival; Gene Expression Regulation, Neoplastic; Humans; Iron; Lipid Metabolism; Melanoma; MicroRNAs; Models, Biological; Piperazines; RNA Interference