Mechanism of HES1 regulating herceptin resistance in gastric cancer cells by ferroptosis / 药学学报

Drug resistance of cancer cells is the main causes of chemotherapy failure, and gene mutation or function loss is key factor to induce drug resistance. Previous studies have shown that hairy and enhancer of split 1 (HES1) is up-regulated in herceptin-resistant gastric cancer cells, and inhibition of its activity can reverse its resistance while the potential mechanism has not yet been elucidated. In this study, we employed CRISPR/Cas9 to establish HES1 knock-out cell line (△HES1/NCI N87R) to investigate the functions of HES1 in herceptin resistance of NCI N87R cells and its potential mechanisms. We investigated proteomics profiling of △HES1/NCI N87R cells based on quantitative proteomics. Gene ontology analysis was conducted by GeneSet Enrichment Analysis (GSEA) and Metascape database, and pathway enrichment analysis was done using GeneAnalytics database. The selected molecules were quantified by Western blot and some pathways were verified by using inhibitors. The results showed that the resistance to herceptin of △HES1/NCI N87R cells decreased compared to NCI N87R cells. Proteomic data demonstrated that the expression of 1 263 genes changed significantly in △HES1/NCI N87R cells, among which 761 genes were up-regulated while 502 ones down-regulated comparing with NCI N87R cells. Pathway analysis showed that ferroptosis, fatty acid β-oxidation, autophagy and glutathione metabolism, etc. exhibited notable changes in △HES1/NCI N87R cells. The functional studies showed that the levels of iron ion and malondialdehyde increased, and glutathione decreased in △HES1/NCI N87R cells. It was further found that Fer-1, a ferroptosis inhibitor, could reverse the expression of pTP53, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) in △HES1/NCI N87R cell, and reduce the sensitivity of △HES1/NCI N87R cells to herceptin. It is suggested that HES1 regulated the resistance of NCI N87R cells to herceptin through TP53/SLC7A11/GPX4 signaling pathway, and targeting TP53/SLC7A11/GPX4 signal axis mediated by HES1 is a potential strategy to reverse herceptin resistance in gastric cancer.

Polysaccharide of Balanophora involucrata Hook. f. attenuates cell ferroptosis in rats with experimental liver injury through SLC7A11/GPX4 pathway / 药学学报

Polysaccharide of Balanophora involucrata Hook. f. (BPS), the major component of Balanophora involucrata Hook. f., was confirmed the protective effect on liver injury in our previous study. This research aimed to investigate the protective mechanism of BPS on experimental liver injury by attenuating cell ferroptosis through modulating solute carrier family 7 member 11/glutathione peroxidase 4 (SLC7A11/GPX4) pathway. The animal experiment was approved by the Experimental Animal Ethical Committee of Hubei Minzu University and all rats had received human care in compliance with the institutional animal care guidelines. Rats were given intraperitoneal injection of (D-galactosamine, D-GalN) solution (800 mg·kg-1) one time to establish the acute liver injury model. The results showed aspartate amino transferase (AST), alanine aminotransferase (ALT) and 4-hydroxynonenal (4-HNE) levels in serum were decreased, and the contents of reactive oxygen species (ROS), Fe2+, malondialdehyde (MDA) and lipid peroxide (LPO) in liver tissues also decreased and glutathione (GSH) level increased after BPS administration with 200 mg·kg-1. Besides, BPS reduced iron deposition and increased the expression of SLC7A11 and GPX4 proteins in liver tissue. In conclusion, BPS ameliorated experimental liver injury by alleviating cell ferroptosis through SLC7A11/GPX4 pathway. The present study pointed to the possibility of utilizing BPS for protection against liver injury in clinic.

Effect and mechanism of ionizing radiation on ferroptosis in mouse hepatocytes / 中华放射肿瘤学杂志

Objective:To investigate the effect and mechanism of ionizing radiation on ferroptosis in mouse hepatocytes.Methods:Twenty-four C57BL/6J mice were divided into two groups by random number table method: healthy control group (control group, n=6) and irradiation group (whole liver was irradiated with a single dose of 30 Gy X-ray, n=18). Mice were sacrificed at 6, 24 and 72 h (6 mice per time point) after irradiation to obtain liver tissue and plasma samples. The contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma were measured by automatic biochemical analyzer. The prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured by automatic biochemical analyzer. Pathological changes of liver tissues were observed by hematoxylin-eosin (HE) staining. The iron deposition in liver tissues was detected by Prussian blue staining. The expression levels of 4-Hydroxynonenal (4HNE) and hepcidin in the liver were determined by immunohistochemical staining, and quantitative analysis was performed. Plasma malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC) and glutathione (GSH) content were determined by microplate reader analysis according to the kit instructions. The expression levels of transferrin receptor 1 (TfR1), p53, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) in the liver were measured by Western blot. Results:Compared with the control group, the plasma contents of ALT ( t=5.15, 5.47, both P<0.001) , AST at 6 and 24 h after irradiation were increased ( t=8.42, 2.50, both P<0.001), the plasma PT was prolonged ( t=3.12, P=0.011) and the APTT was shortened ( t=3.26, P=0.009) at 72 h after radiation in the irradiation group. Histopathological results showed that evident liver edema was observed at 6, 24 and 72 h after irradiation ( t=9.58, 10.09, 18.70, all P<0.001). Different degrees of iron deposition were observed ( t=8.57, 15.31, 32.11, all P<0.001). The infiltration of hepcidin positive cells was significantly increased after irradiation ( t=5.36, 13.17, 17.11, all P<0.001). The number of 4HNE positive cells was significantly increased ( t=18.86, 22.67, 9.12, all P<0.001). At the same time, ionizing radiation induced a significant increase in plasma MDA content ( t=4.36, 7.47, 8.22, all P<0.001), and a decrease in SOD ( t=4.52, 5.80, 7.60, all P<0.001), T-AOC ( t=13.24, 20.49, 24.96, all P<0.001) and GSH ( t=2.78, 6.07, 11.25, P=0.020, <0.001, <0.001), respectively. The expression level of TfR1 protein was significantly up-regulated ( t=3.46, 5.40, P=0.026, 0.006), whereas that of GPX4 protein was significantly down-regulated ( t=11.88, 30.63, both P<0.001) at 24 and 72 h after irradiation. At 6, 24 and 72 h after irradiation, the expression level of p53 protein was significantly up-regulated and maintained at a high level ( t=7.84, 4.25, 8.22, P=0.001, 0.013, 0.001), while that of SLC7A11 protein was significantly down-regulated ( t=9.29, 19.96, 9.09, all P<0.001). Conclusion:Ionizing radiation induces the ferroptosis in hepatocytes, and its mechanism may be related to the activation of p53-SLC7A11-GPX4 pathway.

Hsa_circ_0087354 Regulates Proliferation and Redox State via hsa-miR-199-3p / SLC7A11 in MG-63 Cells / 中国生物化学与分子生物学报

Circular RNAs (circRNAs),a kind of novel non-coding RNAs, have been shown to play animportant role in cellular redox reactions. In the previous study, we found that hsa_circ_0087354 wasclosely related to the cellular redox state by real-time PCR. After overexpression of hsa_circ_0087354, the relative expression of ROS1 were decreased significantly (P < 0. 01), while the levels of SOD1 wereincreased significantly (P < 0. 05) . The activities of SOD and Gpx as well as GSH concentration weresignificantly increased (P < 0. 01), and cell proliferation was promoted in cells (P < 0. 05) . Bioinformatics analysis predicted that there were binding sites between hsa-miR-199-3p and hsa_circ_0087354 as well as solute carrier family 7 member 11 (SLC7A11), which might have a targetedregulatory relationship. Dual luciferase reporter assay confirmed the targeted regulatory relationshipbetween hsa-miR-199-3p with hsa_circ_0087354, and SLC7A11. Overexpressed hsa_circ_0087354 plasmid and ctrl plasmid were constructed, hsa-miR-199a-3p, hsa-miR-199b-3p and hsa-miR-NC mimicswere synthesized. Real-time PCR analysis showed that the relative expression of hsa-miR-199-3p was observably decreased (P < 0.01), while the relative expression of SLC7A11 in cells was dramaticallyincreased after transfection of has_circ_0087354 plasmid (P < 0.05) . After transfection with hsa-miR-199-3p, the relative expressions of SLC7A11 were markedly decreased (P < 0.001) . The activities ofSOD and Gpx, GSH concentration (P<0.01), and cell proliferation rate (P < 0.05) were significantlyreduced. In conclusion, hsa_circ_0087354 could enhance the expression of SLC7A11, promote theproliferation of cells and reduce the oxidative stress by adsorption of hsa-miR-199-3p.

SLC7A11 and glioma / 国际肿瘤学杂志

Glioma is the most common primary brain tumor in adults and is essentially a polygenic abnormal disease. Solute carrier family 7 member 11 (SLC7A11) is a core component of the cystine/glutamate transporter and its expression is regulated at the transcriptional and translational levels. SLC7A11 mediates glioma cells proliferation, invasion and chemoradiotherapy resistance through regulation of oxidative stress and ferroptosis. Deep study of SLC7A11 will provide new theoretical basis and therapeutic targets for the treatment of gliomas.

Effect of SLC7A11 in dexmedetomidine pretreatment induced reduction of ferroptosis caused by intestinal ischemia-reperfusion injury in mice / 中国临床药理学与治疗学

AIM: To evaluate the effect of SLC7A11 in dexmedetomidine pretreatment induced reduction of ferroptosis caused by intestinal ischemia-reperfusion (II/R) injury in mice. METHODS: Twenty-four healthy meal SPF C57BL/6J mice, aged 8 weeks, weighing 22-25 g, were randomly divided into Sham operation group (S group), intestinal I/R group (II/R group), dexmedetomidine group (DEX group) and dexmedetomidine plus SLC7A11 inhibitior group (DIKE group), with 6 mice in each group. Intestinal ischemia was induced by occluding the superior mesenteric artery for 45 min followed by 30 min of reperfusion to establish the model of II/R injury. In DEX and DIKE groups, Dexmedetomidine 25 μg/kg was intraperitoneally injected at 30 min before clamping the superior mesenteric artery. The same amount of normal saline was injected in the S group and the II/R group. In DIKE group, SLC7A11 inhibitior Imidazole ketone erastin 50 mg/kg was intraperitoneally injected at 90 min before ischemia. Mice were sacrificed 30 min after reperfusion, and small intestinal tissues in length 5 cm away from the ileocecal valvum were obtained for microscopic examination of pathological changes of intestinal mucosa and for determination of contents of Fe

Cystine transporter SLC7A11/xCT in cancer: ferroptosis, nutrient dependency, and cancer therapy

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

Ferroptosis, radiotherapy, and combination therapeutic strategies

Ferroptosis, an iron-dependent form of regulated cell death driven by peroxidative damages of polyunsaturated-fatty-acid-containing phospholipids in cellular membranes, has recently been revealed to play an important role in radiotherapy-induced cell death and tumor suppression, and to mediate the synergy between radiotherapy and immunotherapy. In this review, we summarize known as well as putative mechanisms underlying the crosstalk between radiotherapy and ferroptosis, discuss the interactions between ferroptosis and other forms of regulated cell death induced by radiotherapy, and explore combination therapeutic strategies targeting ferroptosis in radiotherapy and immunotherapy. This review will provide important frameworks for future investigations of ferroptosis in cancer therapy.