Mechanism of malignant behavior in cervical cancer cells based on NOD2-mediated AMPK/mTOR signaling pathway / 安徽医科大学学报

ABSTRACT

Objective To explore the mechanism of malignant behavior of cervical cancer(CC)cells based on AMP-activated protein kinase(AMPK)/rapamycin target protein(mTOR)signaling pathway mediated by nucleo-tide-binding oligomerization domain receptor 2(NOD2).Methods Bioinformatics analysis was performed to deter-mine the expression of NOD2 in CC tissue.Plasmids targeting NOD2(shNOD2)and shRNAs negative control(shNC),NOD2 overexpression(NOD2)and vectors(Vec)were transfected into CC cells.The effect of NOD2 on the growth of CC cells was determined by cell counting kit-8 assay,colony formation and Transwell cell invasion as-say.Transcriptome analysis was performed by high throughput RNA sequencing(RNA-Seq).Western blot was used to detect the expression of NOD2,AMPK/mTOR signaling pathway and autophagy protein in the cell line.24 female BALB/c nude mice were randomly divided into four groups,with 6 mice in each group:vector group(Vec group),NOD2 overexpression group(NOD2 group),shNC group and shNOD2 group.The distant metastasis mod-el was established in mice,and the fluorescence intensity of lung metastasis was monitored and the number of lung metastasis nodules was counted.Results On-line database analysis showed that the expression of NOD2 in CC tis-sues was significantly higher than that in normal tissues,and there were significant differences in the mRNA expres-sion of NOD2 in different stages of CC(P＜0.05).In addition,the high expression of NOD2 was associated with poor overall survival and disease-free survival(P＜0.05).NOD2 overexpression promoted the proliferation,colony formation,migration and invasion of CC cells,while NOD2 knock-down was the opposite.Consistent with the re-sults in vitro,the lung colonization and lung metastasis of CC cells in NOD2 group were significantly higher than those in Vec group(P＜0.05),while those in shNOD2 group were significantly lower than those in shNC group(P＜0.05).RNA-Seq results showed that the expression of NOD2 was significantly related to AMPK signal activa-tion,mTOR signal inhibition,autophagy regulation pathway activation and autophagy formation.Compared with shNC group,the expression of phosphorylated AMPK and LC3 protein decreased significantly in shNOD2 group(P＜0.05),and the expression levels of phosphorylated mTOR and p62 protein increased significantly(P＜0.05).Compared with Vec group,the expression levels of LC3 and AMPK protein in NOD2 group increased significantly(P＜0.05),and the expression levels of phosphorylated mTOR and p62 protein decreased significantly(P＜0.05).Compared with shNC group,the point accumulation of GFP-mRFP-LC3 in shNOD2 group decreased signifi-cantly(P＜0.05).Compared with Vec group,the point accumulation of GFP-mRFP-LC3 increased significantly(P＜0.05).Conclusion NOD2 may promote the proliferation,migration and invasion of CC through AMPK/mTOR signal,and its mechanism partly involves autophagy activation.