Extracellular signal regulated kinase 5 promotes cell migration, invasion and lung metastasis in a FAK-dependent manner

This study was designed to evaluate ERK5 expression in lung cancer and malignant melanoma progression and to ascertain the involvement of ERK5 signaling in lung cancer and melanoma. We show that ERK5 expression is abundant in human lung cancer samples, and elevated ERK5 expression in lung cancer was linked to the acquisition of increased metastatic and invasive potential. Importantly, we observed a significant correlation between ERK5 activity and FAK expression and its phosphorylation at the Ser

The Pharmacological Inhibition of ERK5 Enhances Apoptosis in Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is a fatal hematological malignancy which is resistant to a variety of chemotherapy drugs. Extracellular signal-regulated kinase 5 (ERK5) plays a novel role in chemoresistance in some cancer cells and this pathway is a central mediator of cell survival and apoptotic regulation. The aim of this study was to investigate the effect of ERK5 inhibitor, XMD8-92, on proliferation and apoptosis in AML cell lines. Findings showed that XMD8-92 inhibited the activation of ERK5 by G-CSF and decreased the expression of c-Myc and Cyclin D1. The treatment of XMD8-92 reduced the phosphorylation of ERK5 leading to a distinct inhibition of cell proliferation and increased apoptosis in Kasumi-1 and HL-60 cells. Taken together, our study suggests that the inhibition of ERK5 by XMD8-92 can trigger apoptosis and inhibit proliferation in AMLs. Therefore, the inhibition of ERK5 may be an effective adjuvant in AML chemotherapy.

ERK5 and MMP-9 expression levels in osteosarcoma and their clinical significance / 中国肿瘤临床

Objective:To investigate the extracellular signal-regulated kinase 5 (ERK5) and matrix metallo proteinase-9 (MMP-9) expres-sion levels in osteosarcoma tissues and their clinical significance. Methods:The ERK5 and MMP-9 expression levels in 71 specimens of osteosarcoma tissue and 40 specimens of normal bone tissue were detected by immunohistochemistry. The relationship between ERK5 and MMP-9 expression levels, their clinical characteristics, and prognosis of patients with osteosarcoma were analyzed. Results:The positive expression of ERK5 and MMP-9 in osteosarcoma tissues was 85.9%(61/71) and 74.65%(53/71), respectively, which were significantly higher than those in normal bone tissues at 12.5%(5/40) and 10.0%(4/40) (all P<0.05). The positive expression of ERK5 and MMP-9 was associated with Enneking stage and metastasis (all P<0.05). Kaplan-Meier analysis showed that the survival duration of patients with positive ERK5 and MMP-9 expression levels was shorter than those of the patients in the negative expression groups (all P<0.05). Univariate analysis of COX proportional hazards regression model revealed that tumor size, Enneking stage, metastasis, and positive ERK5 and MMP-9 expression levels are relevant to the overall survival of patients with osteosarcoma (all P<0.05). Multi-variate analysis of COX proportional hazards regression model confirmed that Enneking stage, metastasis, and positive ERK5 and MMP-9 expression levels can act as independent prognostic factors for osteosarcoma patients (all P<0.05). Conclusion:The ERK5 and MMP-9 expression levels are high in osteosarcoma tissues and are related to the clinical characteristics and prognosis of patients with osteo-sarcoma. Thus, ERK5 and MMP-9 expression levels may play important roles in osteosarcoma development and progression.

BMP9 Regulates Osteogenic/Odontogenic Differentiation of Immortalized Stem Cells from the Apical Papilla via the ERK5 Pathway / 中国医科大学学报

Objective The aim of this study was to investigate the effects of the ERK5 pathway on bone morphogenetic protein?9(BMP9)?regu?lated osteogenic/odontogenic differentiation of immortalized stern cells from the apical papilla(iSCAP). Methods BMP9 was introduced into the iSCAP by using recombinant adenoviruses,and the P?ERK5 protein expression was measured via western blotting. Then,the osteogenic/odontoblas?tic changes were analyzed by alkaline phosphatase(ALP)staining and Alizarin red staining,and the expression of osteogenic/odontoblast?associat?ed genes,such as Runx2,OCN,OPN,and DMP1 was measured by RT?PCR. Results BMP9 could up?regulate the phosphorylation of ERK5 in iSCAP. After using BIX02189,which was an inhibitor of ERK5,the phosphorylation of ERK5;the activity of ALP;the expression of Runx2, OCN,OPN,and DMP1;and the calcium deposition were all significantly inhibited. Conclusion The ERK5 signaling pathway plays an important role in BMP9?regulated osteogenic/odontogenic differentiation of iSCAP.

Phosphoryaltion levels of ERK5 in acute myocardial infarction patients and its role in platelet activation in vitro / 复旦学报（医学版）

Objective To observe the phosphorylation levels of extracellular signal-regulated kinase 5 (ERK5) in acute myocardial infarction (AMI) patients and the effects of ERK5 selective inhibitor XMD8-92 on human platelet activation in vitro,and to explore its mechanism.Methods Western blot was applied to detect the phosphorylation levels of ERK5,Akt473 and Akt308 in AMI patients (n =34) and stable angina patients (n =33,control).The effects of different concentration of XMD8-92 on human platelet aggregation induced by collagen was tested by aggregometer in vitro.The release of ATP was measured simultaneously by luciferase detection.The effects of XMD8-92 on integrin aIIbβ3 were detected by platelet spreading on immobilized fibrinogen and clot retraction.The effects of XMD8-92 on phosphorylation levels of Akt473,Akt308 PTEN370 and ERK5 were detected by Western blot.Results The levels of phosphor-Akt473,Akt308 and phosphor-ERK5 were significantly higher in AMI patients than that in control group (P＜0.05).ERK5 inhibitor XMD8-92 diminished collagen-induced platelet aggregation,ATP secretion,the average area of platelet spreading on immobilized fibrinogen and the clot retraction extent.The levels of phosphor-Akt (Ser-473/Thr-308) and phosphor-PTEN (Ser370) were significantly down-regulated in the presence of XMD8-92.Conclusions ERK5 plays a role in platelet activation in AMI process.It regulates platelet activation by regulating PTEN and Akt phosphorylation.Its specific inhibitor is hoped to be new antithrombotic drug.

miRNA-199 a-5 p inhibit the invasion of MDA-MB-231 cells via regulating ERK5 through SP1 / 临床与实验病理学杂志

Purpose To study the effect and mechanism of miR-199a-5p on the invasion of breast cancer MDA-MB-231 cells. Meth-ods miR-199a-5p mimic was transfected into MDA-MB-231 cells. Influence of miR-199a-5p on the invasion of MDA-MB-231 cell was displayed by Transwell, the expression of epithelial-mesenchymal transition ( EMT) molecular markers ( E-cadherin, vimentin) regulated by miR-199a-5p was determined using immunofluorescence and Western blot. Western blot was employed to assess the levels of ERK5, pERK5, EGF and SP1 in MDA-MB-231 cells dealt with miR-199a-5p mimic and LNA-siRNA. Chromatin immunoprecipita-tion (CHIP) was applied for displaying the reaction of SP1 with ERK5 promoter. Results miR-199a-5p could inhibit the invasion of MDA-MB-231 cells, decrease the expression of vimentin and enhance E-cadherin. Meanwhile, miR-199a-5p decreased the expression of ERK5 and pERK5, the levels of EGF and SP1 were also downregulated. On the contrary, the levels of EGF, SP1, ERK5 and pERK5 were enhanced by employing LNA-siRNA targeting miR-199a-5p. SP1 could bind with ERK5 promoter. Conclusions miR-199a-5p could reduce the expression of ERK5 and pERK5 through regulating EGF and SP1, which functioning the inhibitory effect on invasion of MDA-MB-231 breast cancer cells.

6 Paths of ERK5 signaling pathway regulate hepatocyte proliferation in rat liver regeneration.

Generally, extra-cellular-signal-regulated kinase 5 (ERK5) signaling pathway regulates many physiological activities, such as cell proliferation and cell differentiation. However, little is known about how ERK5 signaling pathway composed of 15 paths participates in regulating hepatocyte proliferation during liver regeneration (LR). In this study, to explore the influence ERK5 signaling pathway upon hepatocytes at gene transcription level, rat genome 230 2.0 array was used to detect expression changes of 75 related genes in isolated hepatocytes from rat regenerating liver. Bioinformatics and systems biology methods were applied to analyze the precise role of ERK5 signaling pathway in regulating hepatocyte proliferation during LR. Results showed that 62 genes were contained in the array and 22 genes were significantly changed. It was found that 6 paths were related to hepatocyte proliferation during rat LR. Among them, paths 3, 6 and 13 of ERK5 signaling pathway modulated cell cycle progression by decreasing the negative influence on ERK5 and paths 3, 4, 8 and 9 by reinforcing the positive influence on ERK5. In summary, the study shows that 22 genes and 6 paths of ERK5 signaling pathway participate in regulating proliferation of hepatocytes in rat LR.

Laminar flow activation of ERK5 leads to cytoprotective effect via CHIP-mediated p53 ubiquitination in endothelial cells / 대한해부학회지

Atherosclerosis is readily observed in areas where disturbed flow is formed, while the atheroprotective region is found in areas with steady laminar flow (L-flow). It has been established that L-flow protects endothelial cells against endothelial dysfunction, including apoptosis and inflammation. It has also been reported that extracellular signal-regulated kinase 5 (ERK5) regulated endothelial integrity and protected endothelial cells from vascular dysfunction and disease under L-flow. However, the molecular mechanism by which L-flow-induced ERK5 activation inhibits endothelial apoptosis has not yet been determined. Transcription factor p53 is a major pro-apoptotic factor which contributes to apoptosis in various cell types. In this study, we found that 15-deoxy-Delta(12,14)-prostaglandin J2 induced p53 expression and that endothelial apoptosis was reduced under the L-flow condition. This anti-apoptotic response was reversed by the biochemical inhibition of ERK5 activation. It was also found that activation of ERK5 protected endothelial apoptosis in a C terminus of Hsc70-interacting protein (CHIP) ubiquitin ligase-dependent manner. Moreover, molecular interaction between ERK5-CHIP and p53 ubiquitination were addressed with a CHIP ubiquitin ligase activity assay. Taken together, our data suggest that the ERK5-CHIP signal module elicited by L-flow plays an important role in the anti-apoptotic mechanism in endothelial cells.