MiRNA-145-5p inhibits gastric cancer progression via the serpin family E member 1-extracellular signal-regulated kinase-1/2 axis

BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.

Roles of extra-cellular signal-regulated protein kinase 5 signaling pathway in the development of spinal cord injury

Background:In consideration of characteristics and functions,extra-cellular signal-regulated protein kinase 5(ERK5)signaling pathway could be a new target for spinal cord injury(SCI)treatment.Our study aimed to evaluate the roles of ERK5 signaling pathway in secondary damage of SCI.Methods:We randomly divided 70 healthy Wistar rats into five groups:ten in the blank group,15 in the sham surgery+BIX02188(sham+B)group,15 in the sham surgery+dimethyl sulfoxide(DMSO;sham+D)group,15 in the SCI+BIX02188(SCI+B)group,and 15 in the SCI+DMSO(SCI+D)group.BIX02188 is a specific inhibitor of the ERK5 signaling pathway.SCI was induced by the application of vascular clips(with the force of 30 g)to the dura on T10 level,while rats in the sham surgery group underwent only T9-T11 laminectomy.BIX02188 or DMSO was intra-thecally injected at 1,6,and 12 h after surgery or SCI.Spinal cord samples were taken for testing at 24 h after surgery or SCI.Results:Expression of phosphorylated-ERK5(p-ERK5)significantly increased after SCI.Application of BIX02188 indeed inhibited ERK5 signaling pathway and reduced the degree of spinal cord tissue injury,neutrophil infiltration and proinflammatory cytokine expression,nuclear factor-kB(NF-kB)activation and apoptosis(measured by TdT-mediated 20-deoxyuridine 50-triphosphate nickend labeling,expression of Fas-ligand,BCL2-associated X[Bax],and B-cell lymphoma-2[Bcl-2]).Double immunofluorescence revealed activation of ERK5 in neurons and microglia after SCI.Conclusion:ERK5 signaling pathway was activated in spinal neurons and microglia,contributing to secondary injury of SCI.Moreover,inhibition of ERK5 signaling pathway could alleviate the degree of SCI,which might be related to its regulation of infiltration of inflammatory cells and release of inflammatory cytokines,expression of NF-kB and cell apoptosis.