Ursolic acid inhibits the proliferation of triple­negative breast cancer stem­like cells through NRF2­mediated ferroptosis.

Ursolic acid (UA), a pentacyclic triterpenoid that has been found in a broad variety of fruits, spices and medicinal plants, has various biological effects such as reducing inflammation, protecting cells from damage, and preserving brain function. However, its impact on ferroptosis in cancer stem­like cells remains unexplored. The present study investigated the effect of UA on MDA­MB­231 and BT­549 cell­derived triple­negative breast CSCs (BCSCs) and its potential ferroptosis pathway. The effects of ferroptosis on BCSCs were demonstrated by the detection of ferroptosis­related indexes including the intracellular level of glutathione, malondialdehyde, reactive oxygen species and iron. The effects of UA on the biological behaviors of BCSCs were analyzed by Cell Counting Kit­8, stemness indexes detection and mammosphere formation assay. The mechanism of UA induction on BCSCs was explored by reverse transcription­quantitative PCR and western blotting. BALB/c­nude mice were subcutaneously injected with MDA­MB­231­derived BCSCs to establish xenograft models to detect the effects of UA in vivo. The results revealed that BCSCs have abnormal iron metabolism and are less susceptible to ferroptosis. UA effectively reduces the stemness traits and proliferation of BCSCs in spheroids and mice models by promoting ferroptosis. It was observed that UA stabilizes Kelch­like ECH­associated protein 1 and suppresses nuclear factor erythroid­related factor 2 (NRF2) activation. These findings suggested that the ability of UA to trigger ferroptosis through the inhibition of the NRF2 pathway could be a promising approach for treating BCSCs, potentially addressing metastasis and drug resistance in triple­negative breast cancer (TNBC). This expands the clinical applications of UA and provides a theoretical basis for its use in TNBC treatment.

Bicarbonated Ringer's solution improves L-arg-induced acute pancreatitis in rats via the NF-κB and Nrf2 pathways.

OBJECTIVE: Bicarbonated Ringer's solution (BRS), as a new generation of crystalline fluid, has been widely used for intravenous fluid resuscitation in patients with shock diseases. The purpose of our study is to investigate the intervention effects and potential mechanisms of BRS on L-arg-induced AP in rats. METHODS: The AP model was induced by intraperitoneal injection of 20% L-arg. BRS was infused immediately following the previous L-arg injection. The pancreatic tissue was harvested for histological examination. The serum levels of amylase and lipase activity, lactic acid, proinflammatory and anti-inflammatory cytokines were determined. The peroxide and antioxidant activities in the pancreatic tissue were measured. The protein and mRNA levels of nuclear factor-κB, TNF-α, nuclear factor erythroid 2-related Factor 2 and heme oxygenase-1 were determined by Western blot and quantitative reverse transcription PCR analysis. RESULTS: Pancreatic tissue injuries were obviously alleviated, with a significant increase in normal acinar cells after BRS treatment. The serum levels of amylase, lipase, lactic acid, IL-1ß and TNF-α were significantly decreased, while IL-10 was obviously increased by inhibiting the NF-κB pathway and TNF-α. Moreover, Nrf2 pathway and HO-1 were promoted by BRS treatment, which resulted in significantly reduced malondialdehyde and reactive oxygen species levels. In contrast, antioxidant activities, including glutathione peroxidase and so on, were markedly increased after BRS treatment. CONCLUSIONS: Bicarbonated Ringer's solution improves L-arg-induced acute pancreatitis in rats through the NF-κB and Nrf2 pathways, indicating that BRS holds promise as a priority in fluid resuscitation to treat acute pancreatitis.

Role of ferroptosis in promoting cardiotoxicity induced by Imatinib Mesylate via down-regulating Nrf2 pathways in vitro and in vivo.

Imatinib Mesylate (IMA) has been widely used to treat with chronic myeloid leukemia (CML). However, cardiotoxicity associated with IMA is included among the therapeutic strategies. The present study was aimed to discover whether ferroptosis, a programmed iron-dependent cell death, is involved in IMA-induced cardiotoxicity. In vivo, mouse model was established after treated with 25 mg/kg, 50 mg/kg and 100 mg/kg IMA. Serum CK, LDH, AST activities were determined. Cardiac tissues were examined by H&E and Oil Red O staining. MDA was measured to assess production of lipid peroxide. Tissue iron and GSH content were measured. In vitro, cell viability, mitochondria membrane potential, generation of reactive oxygen species (ROS) and cellular iron levels were performed to explore the mechanism of IMA. The in vivo results revealed that IMA treatment significantly increased serum CK, LDH and AST. H&E staining showed that IMA caused cardiac structural injuries. The dose-dependent decrease of GSH and increase of tissue iron and MDA were observed in IMA-treated groups. Oil Red O staining suggested obvious cardiac lipid accumulation after treated with IMA. In H9c2 cardiomyocytes, IMA significantly inhibited cell proliferation in a dose-dependent manner. Mitochondria membrane potential assay showed that IMA destroyed the mitochondrial function. Additionally, IMA increased the cellular ROS and iron levels. Furthermore, IMA down-regulated the expression of Nrf2 and up-regulated the expression of P53 and TfR. These results provided compelling evidence that ferroptosis participates in IMA-induced cardiotoxicity. Ferroptosis could be regarded as a target to protect against cardiotoxicity in IMA-exposed patients.

Resveratrol protects intestinal integrity, alleviates intestinal inflammation and oxidative stress by modulating AhR/Nrf2 pathways in weaned piglets challenged with diquat.

This study investigated the effects of resveratrol (RES) on intestinal morphology, antioxidant capacity, intestinal inflammation, and barrier function in weaned piglets challenged with diquat (DIQ). Thirty weaned piglets were randomly assigned to 5 treatments: non-challenged group (CON), DIQ-challenged group (DIQ), and DIQ-challenged group with 10, 30, or 90 mg/kg of RES, respectively. The trail lasted 21 days, and piglets were intraperitoneally injected with DIQ or the same amount of saline on day 15. The results showed that supplementation with 90 mg/kg RES increased (P < 0.05) jejunal villus height and villus height: crypt depth ratio, and decreased (P < 0.05) crypt depth, plasma D-lactate and diamine oxidase (DAO) compared with the DIQ group. Piglets fed with 30 or 90 mg/kg RES prevented the diquat-induced decrease (P < 0.05) of mRNA expression of occludin, claudin-1, ZO-1, and IL-10, and increase (P < 0.05) of TNF-α mRNA expression. Moreover, addition of 90 mg/kg RES increased (P < 0.05) the activities of SOD, GSH-Px, and CAT and decreased (P < 0.05) the MDA levels in jejunal mucosa compared with the DIQ group. Finally, addition of 90 mg/kg RES enhanced (P < 0.05) the mRNA expression of SOD1, SOD2, CAT, GPx1, and HO-1, and increased (P < 0.05) mRNA and protein expression of Nrf2, NQO1, aryl hydrocarbon receptor (AhR), and cytochrome P450 family 1 member A1 (CYP1A1). These data indicated that supplementation with 90 mg/kg RES was effective in protecting the intestinal integrity, alleviating intestinal inflammation and oxidative stress by activating AhR/Nrf2 pathways in diquat-challenged piglets.

Co-Cr dental alloys induces cytotoxicity and inflammatory responses via activation of Nrf2/antioxidant signaling pathways in human gingival fibroblasts and osteoblasts.

OBJECTIVE: Although cobalt-chromium (Co-Cr) dental alloys are routinely used in prosthodontics, the biocompatibility of Co-Cr alloys is controversial. The aims of the present study were to investigate the effects of Co-Cr alloys on human gingival fibroblasts (HGF) and osteoblasts in an in vitro model as well as their potential molecular mechanisms, focusing on NF-E2-related factor 2 (Nrf2) pathways. METHODS: Cells were directly seeded on prepared Co-Cr alloy discs (15.0mm diameter, 1.0mm thickness) or indirectly treated with Co-Cr alloy located at the bottom of an insert well and incubated for 3 days. Cytotoxicity and reactive oxygen species (ROS) production was evaluated by MTS assay and flow cytometry, respectively. Protein and mRNA levels were determined by Western blotting and RT-PCR analysis, respectively. RESULTS: Cell viability and flow cytometric assay demonstrated that the Co-Cr alloy was cytotoxic to HGFs and osteoblasts, and significantly increased ROS production. In addition, the Co-Cr alloys upregulated pro-inflamamtory cytokines (TNF-α, IL-1ß, IL-6, and IL-8) and increased levels of various inflammatory mediators (iNOS derived nitrite oxide, and COX-2-derived PGE2) in both cells. A mechanistic study showed that Co-Cr alloys activates the NRF2 pathway and up-regulate antioxidant enzymes including heme oxygenase-1 (HO-1). Co-Cr alloys activated JAK2/STAT3, p38/ERK/JNK MAPKs and NF-κB signaling pathways. Furthermore, antioxidants (resveratrol and NAC) and HO-1 inhibitor (SnPP) significantly inhibited the production of ROS and inflammatory mediators, as well as the activation of NF-κB signaling in Co-Cr alloy stimulated HGFs and osteoblasts. SIGNIFICANCE: This study is the first to show that Co-Cr alloys exert cytotoxic and inflammatory effects via activation of Nrf2/ARE signaling and up-regulation of downstream HO-1, which could represent candidate targets for the regulation of inflammatory responses to Co-Cr alloys.