Journal: Redox Biology

Article Title: Redox-triggered USP18 confers cisplatin resistance in ovarian cancer by selectively activating a non-canonical FSP1-dependent ferroptosis escape pathway

doi: 10.1016/j.redox.2026.104179

Figure Lengend Snippet: USP18 Acts as a Key ROS-Responsive Mediator Driving Cisplatin Resistance in Ovarian Cancer. a Mechanisms and incidence of platinum resistance in ovarian cancer (Icons created with BioRender.com ). b Representative images of ROS detection using DCFH-DA probe in cisplatin-resistant and parental SKOV3 cells. Scale bar: 50 μm; GSEA analysis of ROS response genes based on transcriptome sequencing data in cisplatin-resistant and parental SKOV3 cells. c Representative images of ROS detection using DCFH-DA probe in SKOV3 cells treated with vehicle control, cisplatin (20 μM), or cisplatin plus NAC (10 μM) + mito-TEMPO (10 μM). Scale bar: 50 μm; Cell proliferation curves by Real-time cell analysis (RTCA) system (bottom left); LDH release assay in SKOV3 cells treated with cisplatin (20 μM) or cisplatin plus NAC (10 μM) + mito-TEMPO (10 μM) (bottom right). d Representative Immunohistochemistry (IHC) images showing pyroptosis (Cleaved-Caspase-1), apoptosis (Cleaved-Caspase-3), ferroptosis (GPX4), necroptosis (p-MLKL), and autophagy (p62) markers in cisplatin-resistant ovarian cancer PDX model (OV9419) tissues. Scale bar: 100 μm. e Protein expression levels of various cell death markers in OVCAR-3 cells treated with vehicle control, cisplatin (20 μM), or cisplatin plus NAC (10 μM) + mito-TEMPO (10 μM): pyroptosis (Cleaved-Caspase-1), apoptosis (Cleaved-Caspase-3), ferroptosis (GPX4), necroptosis (p-MLKL), and autophagy (LC3 II/LC3 I). f Schematic of DUB screening for cisplatin resistance: DUB plasmid library transfected into A2780 cells, treated with cisplatin (10 μM) after 24h, and cell viability measured by CCK8 after another 48h. Scatter plot shows relative cell viability compared to control. g Protein expression levels of USP18, USP37, and USP39 in parental and cisplatin-resistant SKOV3 cells. h Protein expression levels of USP18, USP37, and USP39 in OVCAR-3 cells treated with vehicle control, cisplatin (20 μM), or cisplatin (20 μM) plus NAC (10 μM) + mito-TEMPO (10 μM). i Protein expression levels of USP18, USP37, and USP39 in tissues from cisplatin-sensitive (n = 4) and -resistant (n = 4) ovarian cancer patients. j Analysis of USP18 expression in ovarian cancer versus normal ovarian tissues using data from The Cancer Genome Atlas (TCGA) ( www.aclbi.com ) k Survival analysis of patients with differential USP18 using data from TCGA. Analysis was performed via the KM-plotter platform ( https://kmplot.com/ ). l Representative IHC staining of USP18 shows its expression patterns in ovarian cancer tissues compared with paired adjacent tissues, and in therapy-sensitive versus resistant cases. Scale bar: 100 μm. Patients were stratified into high and low USP18 expression groups based on the median IHC score, and the distribution was compared using the Chi-squared test. m Analysis of USP18 expression in ovarian cancer patients stratified by response to platinum-based therapy using the ROC plot online platform ( https://rocplot.com/ ). n Protein expression levels of USP18 in ovarian cancer cell lines. o Cisplatin IC 50 values in ovarian cancer cell lines. p Pearson correlation analysis between USP18 protein levels (n) and cisplatin IC 50 (o). Data presented as mean ± SD. Significance calculated by unpaired two-tailed t -test (c). ∗∗P < 0.01; ∗∗∗∗P < 0.0001.

Article Snippet: All sequencing procedures were performed by Annoroad Gene Tech. (Beijing) Co., Ltd.

Techniques: Sequencing, Control, Cell Analysis, Lactate Dehydrogenase Assay, Immunohistochemistry, Expressing, Plasmid Preparation, Transfection, Two Tailed Test

Journal: Redox Biology

Article Title: Redox-triggered USP18 confers cisplatin resistance in ovarian cancer by selectively activating a non-canonical FSP1-dependent ferroptosis escape pathway

doi: 10.1016/j.redox.2026.104179

Figure Lengend Snippet: Elevated ROS levels upregulate c-JUN expression, which transcriptionally activates downstream USP18 in cisplatin-resistant ovarian cancer cells. a GSEA analysis of hallmark ROS pathway genes from transcriptome sequencing in OVCAR-3 cells overexpressing USP18 plasmid and vector. b Heatmap of transcriptome sequencing expression values for ROS pathway-related genes in A2780 cells overexpressing USP18 plasmid and vector. c Differentially expressed genes in OVCAR-3 cells treated with sodium arsenite (NaAsO2, 0.5 mM) versus vehicle control. d Differentially expressed genes in SKOV3 cells treated with cisplatin (20 μM) vs vehicle control. e Venn diagram of ROS pathway-related upregulated transcription factors identified from transcriptome sequencing data in c and d. f Analysis of JUN expression in ovarian cancer patients stratified by response to platinum-based therapy using the ROC plot online platform. g Survival analysis of patients with differential JUN expression using data from TCGA. Analysis was performed via the KM-plotter platform. h Protein expression levels of c-JUN and USP18 in OVCAR-3 cells treated with vehicle control, cisplatin (20 μM), or cisplatin (20 μM) plus NAC (10 μM) + mito-TEMPO (10 μM). i Protein expression levels of c-JUN and USP18 in OVCAR-3 cells treated with vehicle control, NaAsO2 (0.5 mM), or NaAsO2(0.5 mM) plus NAC (10 μM) + mito-TEMPO (10 μM). j Cell viability measured by CCK8 assay in OVCAR-3 and A2780 cells overexpressing USP18 and treated with cisplatin (10 μM) plus NAC (10 μM) + mito-TEMPO (10 μM) k RT-qPCR analysis of USP18 mRNA expression levels in OVCAR-3 cells treated with vehicle control, cisplatin (10 μM), or cisplatin combined with c-JUN knockdown. l Schematic of predicted c-JUN binding sites in the USP18 promoter region ( https://jaspar.elixir.no/ ). m ChIP assay in CAOV3 cells validating c-JUN binding to USP18. n-p Dual-luciferase reporter assay confirming c-JUN binding and transcriptional regulation of USP18. n Schematic diagram of the dual-luciferase reporter assay. o Overexpression of c-JUN activates the USP18 promoter. OVCAR-3/CAOV3 cells were co-transfected with the USP18 promoter reporter construct and a c-JUN expression plasmid (or empty vector control). p OVCAR-3 cells transfected with the USP18 promoter reporter were treated with vehicle control, cisplatin (10 μM), or cisplatin (10 μM) combined with c-JUN knockdown (sic-JUN). Data presented as mean ± SD. Significance calculated by unpaired two-tailed t -test (j, k, m, o, p). ∗P < 0.05; ∗∗P < 0.01; ∗∗∗P < 0.001; ∗∗∗∗P < 0.0001.

Article Snippet: All sequencing procedures were performed by Annoroad Gene Tech. (Beijing) Co., Ltd.

Techniques: Expressing, Sequencing, Plasmid Preparation, Control, CCK-8 Assay, Quantitative RT-PCR, Knockdown, Binding Assay, Luciferase, Reporter Assay, Over Expression, Transfection, Construct, Two Tailed Test