The Role And Its Underlying Mechanisms Of MTG1 In Lung Adenocarcinoma Cells

Objective: At present,as one of the most common types of cancer,lung cancer is threatening people’s health and life worldwide.Therefore,the changes of genes and molecules in tumor cells have become more and more important for the selection of tumor treatment programs.Melanocyte proliferating gene 1(MYG1)is an exonuclease that participates in RNA processing and is required for normal mitochondrial function.However,its role in tumorigenesis remains unknown.The present study aimed to investigate the role of MYG1 and its underlying mechanisms in human lung adenocarcinoma(LUAD).Methods: 1.The expression levels of MYG1 in tumor tissues of LUAD patients and The American Joint Committee on Cancer(AJCC)stages were obtained from public cancer databases of The Cancer Genome Atlas(TCGA)and analyzed using the UALCAN online software.The correlation between clinicopathological characteristics and MYG1 expression level,such as age,sex,TNM stage,Clinical stage,predicted DLCO,bronchodilator FEV1,location in LUAD,tumor status,smoking history indicator and packs of cigarettes per year,was analyzed.2.The association between MYG1 expression levels and overall survivalm(OS),first progression(FP)and post-progression survival(PPS)of patients with LUAD was analyzed using the Kaplan-Meier plotter.Cox regression was used to analyze the influence of multiple variables such as sex,stage,AJCC stage T,AJCC stage N,smoking history and MYG1 expression on these three.3.TCGA LUAD gene expression data were analyzed using gene-set enrichment analysis(GESA).A549 and H1993 cells were transfected with a specific small interfering RNA or a MYG1-containing plasmid.Cell proliferation and colony formation were used to detect cell proliferation after48 h.Transwell and wound healing assays were used to detect cell migration and invasion after 24 h.The expression levels of MYG1 protein,autophagy marker including LC3 and p62 protein,AMPK and phospho-AMPK protein,and m TORC1 substrate p70 S6 K and phospho-p70 S6 K protein were detected by Western blot after 48 h,and the expression levels of.ATP activity was detected by chemiluminescence.Results: 1.In the TCGA database,the expression of MYG1 was significantly increased in LUAD tissues compared with normal tissues(P <0.05),and its expression level was correlated with AJCC stage N(P <0.05),but not with other clinicopathological features(P>0.05).2.Analysis results in TCGA database showed that MYG1 expression was negatively correlated with OS and PPS(P<0.05),and there was no statistical significance between MYG1 expression and FP(P>0.05).3.GESA showed that MYG1 was related to oxidative phosphorylation and m TORC1 signaling.Cell proliferation and colony formation demonstrated that MYG1 over-expression promoted cell proliferation and colony formation compared with those in the empty vector transfected cells.The results of the Transwell and wound healing assays revealed that overexpression of MYG1 significantly increased the number of the cells that crossed the membrane compared with those in the control group.The results of western blot analysis demonstrated that overexpression of MYG1 led to an increase in p62 protein expression levels,as well as a decrease in the ratio of LC3B‐II/LC3B‐I,MYG1 overexpression decreased the levels of a MPKαphosphorylation whereas increased the phosphorylation levels of p70S6 K compared with those in the corresponding control groups.Conclusions: Collectively,MYG1 promoted cell proliferation,migration and invasion and inhibited autophagy through AMP-activated protein kinase/m TOR complex 1 signaling pathway in human LUAD A549 and H1993 cells,and may be a potential therapeutic target for LUAD.