Isoliensinine activated the Nrf2/GPX4 pathway to inhibit glutamate-induced ferroptosis in HT-22 cells.

Isoliensinine (ISO), a natural compound, is a bibenzyl isoquinoline alkaloid monomer in lotus seed, which has strong antioxidant and free radical scavenging activities. The oxidative toxicity caused by glutamic acid overdose is one of the important mechanisms of nerve cell injury, and the oxidative toxicity caused by glutamic acid is related to ferroptosis. This study aims to establish a glutamate-induced injury model of mouse hippocampal neurons HT-22 cells, and investigate the protective effect of ISO on the neurotoxicity of glutamate-induced HT-22 cells. The results showed that ISO inhibited glutamate-induced ferroptosis of neuronal cells through nuclear factor E2-related factor 2/glutathione peroxidase 4 (Nrf2/GPX4) signaling pathway. Pretreatment of HT-22 cells with ISO significantly reduced glutamate-induced cell death. Ferroptosis inhibitors have the same effect. ISO inhibited the decrease of mitochondrial membrane potential detection and the increase of iron content induced by glutamate, the increase of malondialdehyde and reactive oxygen species in cytoplasm and lipid, and protected the activities of GPx and superoxide dismutase enzymes. In addition, WB showed that glutamic acid could induce the upregulated expression of long-chain esteryl coA synthase 4 (ACSL4) protein and the downregulated expression of SLC7A11 and GPX4 protein in HT-22 cells, while ISO could prevent the abnormal expression of these proteins induced by glutamic acid. The nuclear translocation of Nrf2 in HT-22 cells was increased, and the expression of downstream heme oxygenase-1 protein was upregulated. In summary, ISO protects HT-22 cells from glutamate-induced ferroptosis through a novel mechanism of the Nrf2/GPX4 signaling pathway.

Dihydroisotanshinone I regulates ferroptosis via PI3K/AKT pathway to enhance cisplatin sensitivity in lung adenocarcinoma.

OBJECTIVES: Dihydroisotanshinone I (DT) is a kind of diterpenoid compound extracted from the dried roots of Salvia miltiorrhiza Bunge, and exhibits multiple biological activities including anti-tumor activity. Cisplatin is one of the first-line drugs for the treatment of lung adenocarcinoma (LAUD), but the drug resistance and toxicity limit its efficacy. DT is known to induce apoptosis and ferroptosis, but it is unclear whether DT can inhibit the cisplatin-resistant LAUD cells and reverse the drug resistance in LAUD. Therefore, our study intends to establish the cisplatin-resistant human LAUD cells (A549/DDP), and figure out the influence and related mechanisms of DT reversing cisplatin resistance in A549/DDP cells, so as to provide a theoretical basis for the DT as a new natural candidate for the treatment of LAUD. METHODS: The establishment of A549/DDP was the continuous stimulation by exposing A549 to gradient concentrations of Cisplatin. The cell viability of A549 and A549/DDP was detected by CCK-8 kit, and the IC50 value was calculated. The morphological changes of A549 and A549/DDP cells were observed by an inverted microscope. The contents of malondialdehyde (MDA) and glutathione (GSH) in A549/DDP cells after drug treatment were detected by related kits. The levels of Fe2+, cytosolic reactive oxygen species (ROS), and lipid reactive oxygen species (lipid ROS) were detected by a fluorescence microplate reader or fluorescence cell imager according to the related fluorescent probe kit instructions. Western blot was used to detect the expressions of PI3K, phospho-PI3K, AKT, phospho-AKT, MDM2, p53, GPX4, and SLC7A11 in A549/DDP after different drug treatments. KEY FINDINGS: Our study demonstrated that the inhibitory effect of DT on A549 and A549/DDP cells was time-dependent and concentration-dependent, and DT and DDP had a synergistic effect on inhibiting the proliferation of A549/DDP cells. Furthermore, DT mainly induced ferroptosis in A549/DDP cells and synergized with cisplatin to promote ferroptosis in A549/DDP cells. The result of KEGG pathway analysis, molecular docking and western blot showed that DT could enhance the cisplatin sensitivity of A549/DDP by inhibiting PI3K/MDM2/P53 signaling pathway. CONCLUSIONS: Consequently, we concluded that DT promotes ferroptosis in cisplatin-resistant LAUD A549/DDP cells. Additionally, DT reverses cisplatin resistance by promoting ferroptosis via PI3K/MDM2/P53 pathway in A549/DDP cells.

Pharmacokinetic and Safety Study of Bismuth Potassium Citrate Formulations in Healthy Subjects.

BACKGROUND: Potassium bismuth citrate is a gastric mucosal protector and a key drug for treating peptic ulcers. OBJECTIVE: To evaluate the pharmacokinetic characteristics and safety of 120-mg bismuth potassium citrate formulations administered orally under fasting conditions in healthy Chinese subjects. METHOD: A single-center open two-cycle trial was conducted on 12 healthy subjects who received a single oral dose of 120 mg of bismuth potassium citrate. The plasma concentration of bismuth was determined using a validated inductively coupled plasma mass spectrometry (ICP‒MS) method. The pharmacokinetic parameters, including maximum serum concentration (Cmax) and area under the curve concentration-time curve (AUC0-t and AUC0-∞), and safety were evaluated via noncompartment analysis. RESULTS: The ratios of the least square geometric mean ratio between the test (T) and reference (R) formulations for Cmax, AUC0-t, and AUC0-∞ were 44.8%, 55.5%, and 64.4%, respectively; the bilateral 95% confidence intervals (Cis) for these parameters were 20.2-99.6%, 24.1-127.5%, and 23.7-175.0%, respectively, and the non-inferior limits for these parameters were 169.4%, 198.8%, and 200.5%, respectively. The upper limits of the one-sided 97.5% confidence interval for the least squares geometric mean ratio (T/R) were lower than the non-inferior limits. No serious adverse reactions or adverse reactions leading to detachment were observed among the subjects. CONCLUSION: The concentration of bismuth in the blood of healthy subjects in the T formulation was not greater than that in the R formulation. Similarly, the safety of oral administration of 120 mg of bismuth potassium citrate formulations to healthy subjects was good. The trial registration number (TRN) was [2018] 013, 6 December 2018.

Relationship between miRNA and ferroptosis in tumors.

Malignant tumor is a major killer that seriously endangers human health. At present, the methods of treating tumors include surgical resection, chemotherapy, radiotherapy and immunotherapy. However, the survival rate of patients is still very low due to the complicated mechanism of tumor occurrence and development and high recurrence rate. Individualized treatment will be the main direction of tumor treatment in the future. Because only by understanding the molecular mechanism of tumor development and differentially expressed genes can we carry out accurate treatment and improve the therapeutic effect. MicroRNA (miRNA) is a kind of small non coding RNA, which regulates gene expression at mRNA level and plays a key role in tumor regulation. Ferroptosis is a kind of programmed death caused by iron dependent lipid peroxidation, which is different from apoptosis, necrosis and other cell death modes. Now it has been found that ferroptosis plays an important role in the occurrence and development of tumors and drug resistance. More and more studies have found that miRNAs can regulate tumor development and drug resistance through ferroptosis. Therefore, in this review, the mechanism of ferroptosis is briefly outlined, and the relationship between miRNAs and ferroptosis in tumors is reviewed.