Explore the vast range of titles available.

(1) Background: Extracellular signal-regulating kinase 5 (ERK5) has been implicated in many cellular functions, including survival, proliferation, and vascularization. Our objectives were to examine the expression and effect of ERK5 in clear cell renal cell carcinoma (ccRCC). (2) Methods: The expressions of ERK5 and its regulating micro-RNA miR-143 were investigated using immunohistochemistry and quantitative reverse transcriptase PCR in surgical specimens of ccRCC patients. With invitro and in vivo studies, we used pharmacologic ERK5 inhibitor XMD8-92, RNA interference, pre-miR-143 transduction, Western blotting, MTS assay, apoptosis assay, and subcutaneous xenograft model. (3) Results: A strong ERK5 expression in surgical specimen was associated with high-grade (p = 0.01), high-recurrence free rate (p = 0.02), and high cancer-specific survival (p = 0.03). Expression levels of ERK5 and miR-143 expression level were correlated (p = 0.049). Pre-miR-143 transduction into ccRCC cell A498 suppressed ERK5 expression. ERK5 inhibition enhanced cyclin-dependent kinase inhibitor p21 expression and decreased anti-apoptotic molecules BCL2, resulting in decreased cell proliferation and survival both in ccRCC and endothelial cells. In the xenograft model, ERK5 inhibitor XMD8-92 suppressed tumor growth. (4) Conclusions: ERK5 is regulated by miR-143, and ERK5 inhibition is a promising target for ccRCC treatment.

Oxidative stress and neuroapoptosis are key pathological processes after subarachnoid hemorrhage (SAH). The present study evaluated the anti-oxidation and anti-apoptotic neuroprotective effects of the apoptosis signal-regulating kinase 1 (ASK1) inhibitor ethyl-2,7-dioxo-2,7-dihydro-3H-naphtho(1,2,3-de)quinoline1-carboxylate (NQDI-1) in early brain injury (EBI) following SAH in a rat model. A total of 191 rats were used and the SAH model was induced using monofilament perforation. Western blotting was subsequently used to detect the endogenous expression levels of proteins. Immunofluorescence was then used to confirm the nerve cellular localization of ASK1. Short-term neurological function was assessed using the modified Garcia scores and the beam balance test 24 h after SAH, whereas long-term neurological function was assessed using the rotarod test and the Morris water maze test. Apoptosis of neurons was assessed by TUNEL staining and oxidative stress was assessed by dihydroethidium staining 24 h after SAH. The protein expression levels of phosphorylated (p-)ASK1 and ASK1 rose following SAH. NQDI-1 was intracerebroventricularly injected 1 h after SAH and demonstrated significant improvements in both short and long-term neurological function and significantly reduced oxidative stress and neuronal apoptosis. Injection of NQDI-1 caused a significant decrease in protein expression levels of p-ASK1, p-p38, p-JNK, 4 hydroxynonenal, and Bax and significantly increased the protein expression levels of heme oxygenase 1 and Bcl-2. The use of the p38 inhibitor BMS-582949 or the JNK inhibitor SP600125 led to significant decreases in the protein expression levels of p-p38 or p-JNK, respectively, and a significant reduction in oxidative stress and neuronal apoptosis; however, these inhibitors did not demonstrate an effect on p-ASK1 or ASK1 protein expression levels. In conclusion, treatment with NQDI-1 improved neurological function and decreased oxidative stress and neuronal apoptosis in EBI following SAH in rats, possibly via inhibition of ASK1 phosphorylation and the ASK1/p38 and JNK signaling pathway. NQDI-1 may be considered a potential agent for the treatment of patients with SAH.

The plant hormone ABA (abscisic acid) plays an extremely important role in plant growth and adaptive stress, including but are not limited to seed germination, stomatal closure, pathogen infection, drought and cold stresses. Reactive oxygen species (ROS) are response molecules widely produced by plant cells under biotic and abiotic stress conditions. The production of apoplast ROS is induced and regulated by ABA, and participates in the ABA signaling pathway and its regulated plant immune system. In this review, we summarize ABA and ROS in apoplast ROS production, plant response to biotic and abiotic stresses, plant growth regulation, ABA signal transduction, and the regulatory relationship between ABA and other plant hormones. In addition, we also discuss the effects of protein post-translational modifications on ABA and ROS related factors.

We previously identified receptor tyrosine kinase‐like orphan receptor 1 (ROR1) as a transcriptional target of the NKX2‐1/TTF‐1 lineage‐survival oncogene in lung adenocarcinoma. ROR1 consequently sustains a favorable balance between pro‐survival phosphatidylinositol 3‐kinase–protein kinase B and pro‐apoptotic apoptosis signal‐regulating kinase 1 (ASK1)‐p38MAPK signaling. In contrast to recent advances in understanding how ROR1 sustains pro‐survival signaling, the mechanism of ROR1 repression of pro‐apoptotic signaling remains rather elusive. In the present study, we investigated the underlying mechanism of ROR1‐mediated inhibition of the ASK1‐p38MAPK signaling pathway. Growth inhibition mediated by siROR1 was partially but significantly alleviated by ASK1 co‐knockdown in lung adenocarcinoma cell lines. Also, ASK1 phosphorylation at Thr845, which reflects its activated state, was clearly inhibited by ROR1 overexpression in both steady state and oxidative stress‐elicited conditions in MSTO‐211H cells. In addition, we found that ROR1 was physically associated with ASK1 at the C‐terminal serine threonine‐rich domain of ROR1. Furthermore, ROR1 kinase activity was shown to be required to repress the ASK1–p38 axis and oxidative stress‐induced cell death. The present findings thus support our notion that ROR1 sustains lung adenocarcinoma survival, at least in part, through direct physical interaction with ASK1 and consequential repression of the pro‐apoptotic ASK1–p38 axis in a ROR1 kinase activity‐dependent manner. We investigated the underlying mechanism of ROR1‐mediated inhibition of the ASK1‐p38MAPK signaling pathway. As a result, we have found that ROR1 inhibits ASK1 activity in an ROR1 kinase‐dependent manner via physical interaction at the C‐terminal serine threonine‐rich domain of ROR1.

The aim of the present study was to investigate the effect of solanine on promoting human hepatocellular carcinoma HepG2 cells to produce reactive oxygen species (ROS), and the molecular mechanisms leading to tumor cell apoptosis. Solanine was administered to HepG2 cells in vitro. A selection of probes targeting various cellular localizations of ROS were used to detect ROS expression using flow cytometry. The expression levels of apoptosis-associated proteins, including apoptosis signal-regulating kinase 1 (ASK1) and thioredoxin binding protein 2 (TBP-2), and proliferation-associated proteins, including histone deacetylase 1 (HDAC1), were detected using western blotting. The percentage of cells undergoing apoptosis was measured using an Annexin V-fluorescein isothiocyanate/propidium iodide assay, and cell morphology was examined using Wright's stain followed by inverted microscopy analysis. ROS detection probes 2′,7′-dichlorofluorescin diacetate and dihydrorhodamine 123 identified that abundant ROS, including hydroxyl radical (OH−) and hydrogen peroxide (H2O2), were produced in the cytoplasm and mitochondria of the solanine-treated HepG2 cells compared with the control cells (P<0.05). Superoxide anion specific probes dihydroethidium and MitoSOX™ demonstrated that there were no significant alterations in the HepG2 cells following solanine treatment compared with the control cells (P>0.05). Western blotting results revealed that solanine upregulated the expression levels of ASK1 and TBP-2 and enhanced their kinase activities, whereas solanine decreased the expression level of the proliferation-associated protein, HDAC1. The cell apoptotic rate was significantly increased (P<0.0001) in the solanine-treated HepG2 cells compared with the control cells. (P<0.05). Overall, the study indicated that solanine induces HepG2 cells to produce ROS, mainly OH− and H2O2, in a mitochondria-dependent and -independent manner. In addition, solanine stimulates the expression of ASK1 and TBP-2, and their kinase activities, but inhibits the expression of proliferation-associated proteins, such as HDAC1, thus contributing to HepG2 cell apoptosis.

Objective: To explore the mechanisms underlying endothelin-1 (ET-1) elevations induced by excessive fluoride exposure. Methods: We measured serum and bone fluoride ion content and plasma ET-1 levels and compared these parameters among different groups in an animal model. We also observed morphological changes in the aorta and endothelium of rabbits. In cell experiments, human umbilical vein endothelial cells (HUVECs) were treated with varying concentrations of NaF for 24h, with or without 10 µM U0126 pretreatment for 1 h. ET-1 levels in culture fluid and intracellular reactive oxygen species (ROS) levels, as well as ET1 gene, endothelin-converting enzyme-1 (ECE-1), extracellular signal-regulating kinase 1/2 (ERK1/2), pERK1/2 expression levels and RAS activation were measured and compared among the groups. Results: Plasma ET-1 levels of rabbits increased significantly in fluorinated groups compared with those in the control group. The rabbit thoracic aortas became slightly hardened in fluorinated groups compared with those in the control group, and some vacuoles were present in the endothelial cell cytoplasm of the rabbits in fluorinated groups. In our cell experiments, ET1 gene and ECE-1 expression levels in HUVECs and ET-1 expression levels in the cell culture supernatants increased significantly in some experimental groups compared with those in the control group. These trends paralleled the changes in intracellular ROS levels, RAS activation, and the pERK1/2-to-ERK1/2 ratio. After U0126 was added, ECE-1 expression and ET-1 levels decreased significantly. Conclusion: Excessive fluoride exposure leads to characteristic endothelial damage (vacuoles), thoracic aorta hardening, and plasma ET-1 level elevations in rabbits. In addition, the ROS-RAS-MEK1/2-pERK1/2/ERK1/2 pathway plays a crucial—and at least partial—role in ET-1 over-expression, which is promoted by excessive fluoride exposure.

SERPINA5 belongs to the serine protease inhibitor superfamily and has been reported to be lowly expressed in a variety of malignancies. However, few report of SERPINA5 in gastric cancer has been found. The purpose of this study was to determine the role of SERPINA5 in GC and to investigate potential tumorigenic mechanisms. We performed qPCR to determine the level of SERPINA5 expression in GC. We used public databases to evaluate whether SERPINA5 could be utilized to predict overall survival and disease‐free survival in GC patients. We also knocked down the expression of SERPINA5 and evaluated its effect on cell proliferation and migration. Furthermore, we explored the signal pathways and regulatory mechanisms related to SERPINA5 functions. According to our findings, SERPINA5 was shown to exhibit high expression in GC. Notably, SERPINA5 was prognostic in GC with high expression being unfavourable. SERPINA5 was further observed to promote GC tumorigenesis by modulating GC cell proliferation ability. Mechanically, SERPINA5 could inhibit CBL to regulate the PI3K/AKT/mTOR signalling pathway, thereby promoting GC carcinogenesis progression. These results highlight the important role of SERPINA5 in GC cell proliferation and suggest that SERPINA5 could be a novel target for GC treatment and a predictor for GC prognosis.

Casticin is one of the main components of the fruits of Vitex rotundifolia L. Studies have shown that casticin inhibits the growth of various cancer cells, including colon cancer. In the present study, the anti-carcinogenic effects of casticin on human colon cancer and the underlying mechanisms were investigated. The results revealed that casticin significantly induced apoptosis of HT-29, HCT-116, SW480 and Caco-2 cells, induced the accumulation of reactive oxygen species (ROS) and increased the protein levels of apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK) and B-cell lymphoma 2-interacting mediator of cell death (Bim) in HT-29 cells. Pretreatment with N-acetylcysteine, an antioxidant chemical compound, inhibited the activation of ASK1, JNK and Bim, as well as the apoptosis induced by casticin. Small interfering RNA targeting ASK1 significantly attenuated the induction of JNK and Bim activation and apoptotic cell death by casticin treatment. SP600125, a specific JNK inhibitor, attenuated Bim activation and apoptosis, but did not alter ASK1 phosphorylation levels. In addition, casticin treatment resulted in apoptosis by the same mechanism in HCT-116, SW480 and Caco-2 cells. These results suggest that casticin significantly induced apoptosis by the activation of the ASK1-JNK-Bim signaling cascade and the accumulation of ROS in colon cancer cells.

Heart failure has been identified as one of the clinical manifestations of diabetic cardiovascular complications. Excessive myocardium apoptosis characterizes cardiac dysfunctions, which are correlated with an increased level of advanced glycation end products (AGEs). In this study, we investigated the participation of reactive oxygen species (ROS) and the involvements of apoptosis signal‐regulating kinase 1 (ASK1)/mitogen‐activated protein kinase (MAPK) kinases (MKKs)/p38 MAPK and nuclear factor κB (NF‐κB) pathways in AGE‐induced apoptosis‐mediated cardiac dysfunctions. The antioxidant and therapeutic effects of a novel ASK1 inhibitor, AGI‐1067, were also studied. Myocardium and isolated primary myocytes were exposed to AGEs and treated with AGI‐1067. Invasive hemodynamic and echocardiographic assessments were used to evaluate the cardiac functions. ROS formation was evaluated by dihydroethidium fluorescence staining. A terminal deoxynucleotidyl transferase dUTP nick end labelling assay was used to detect the apoptotic cells. ASK1 and NADPH activities were determined by kinase assays. The association between ASK1 and thioredoxin 1 (Trx1) was assessed by immunoprecipitation. Western blotting was used to evaluate the phosphorylation and expression levels of proteins. Our results showed that AGE exposure significantly activated ASK1/MKKs/p38 MAPK, which led to increased cardiac apoptosis and cardiac impairments. AGI‐1067 administration inhibited the activation of MKKs/p38 MAPK by inhibiting the disassociation of ASK1 and Trx1, which suppressed the AGE‐induced myocyte apoptosis. Moreover, the NF‐κB activation as well as the ROS generation was inhibited. As a result, cardiac functions were improved. Our findings suggested that AGI‐1067 recovered AGE‐induced cardiac dysfunction by blocking both ASK1/MKKs/p38 and NF‐κB apoptotic signaling pathways. Advanced glycation end product exposure activates the ASK1/MKKs/p38 MAPK signaling pathway, which triggers myocyte apoptosis, leading to cardiac systolic/diastolic impairments. The ASK1 inhibitor AGI‐1067 inhibits the activation of MKKs/p38 MAPK by inhibiting the disassociation of ASK1 and Trx1. Moreover, AGI‐1067 also suppressed reactive oxygen species formation and NF‐κB activation.

Mechanisms of bacterial predation are crucial for revealing microbial adaptation strategies and interaction behaviors in the environment, yet they remain poorly understood. Previously, predators were reported to localize prey via specific cues. However, the process and mechanisms by which these cues, including signaling molecules, mediate predator localization remain unclear. Herein, we investigate the dynamic interaction between the predatory bacteria Lysobacter enzymogenes and its prey bacteria. By integrating genetic manipulation, transcriptomic analysis, biochemical assays, and live-cell tracking microscopy at the single-cell level, we present a novel predation strategy mediated by peptidoglycan hydrolase LssL, named peptidoglycan hydrolase-driven Prey Localization and Utilization System (phPLUS). In phPLUS, predators secrete LssL to initiate the Step I of the localization process. LssL then hydrolyzes prey and releases small molecules of glycine, which serve as signaling cues to guide the predator’s directional movement and promote the Step II of localization. In turn, prey signals upregulate the expression of LssL, which synergize with type VI secretion system to ultimately mediate prey killing through a novel regulatory pathway. This study reveals a new two-step localization strategy in bacterial predation, highlighting a previously unrecognized predation process and signal regulation mechanism, and expanding our understanding of predator–prey interactions and microbial ecological dynamics.