Preliminary Study On Expression And Function Of DARS2 In Lung Adenocarcinoma

Background and Objective : With the rapid growth and aging of the global population,the incidence and the death rates of cancer are increasing rapidly worldwide.According to the GLOBOCAN estimate in 2020,there are almost 19.3million new cancer cases and nearly 10 million cancer deaths worldwide in this year,of which lung cancer is the most common cancer after female breast cancer,and also the leading cause of cancer death.In recent years,in addition to the traditional surgery,chemotherapy and radiotherapy,the discovery of targeted drugs has brought new hope for the treatment of lung cancer,but due to individual differences and drug resistance,the long-term efficacy is not satisfactory.A number of studies have confirmed that AARS in higher eukaryotes is involved in RNA splicing,transcription and translation regulation,cell apoptosis,and tumorigenesis.And DARS2 is the gene that encodes asparagyl-t RNA synthetase,one of mitochondrial AARS.DARS2 was first discovered by Scheper GC et al.in patients with LBSL in 2007.A study from Zhongnan Hospital of Wuhan University found that the expression level of DARS2 is associated with tumor size,differentiation status,stage of BCLC,distant metastasis,portal vein invasion,and prognosis of Liver Cancer.However,the research on the relationship between DARS2 and lung cancer has not been reported at home and abroad,and the role of DARS2 in the occurrence and development of lung cancer is not clear also.Therefore,it is of great significance to analyze the expression level of DARS2 in lung adenocarcinoma and study the influence of DARS2 on the biological behavior of lung adenocarcinoma cells for discovering new diagnostic methods,more effective treatment methods and new measures to improve the prognosis of lung cancer.Methods:In this study,we searched TCGA and downloaded lung adenocarcinoma expression spectrum data,and analyzed them.Then q RT-PCR and Western blot were used to detect the expression level and difference of DARS2 between lung adenocarcinoma tissues and para-carcinoma tissues in 45 patients who were operated on for lung adenocarcinoma in thoracic surgery department from May 2019 to May2020 in Fujian Provincial Hospital.The relationship between the expression level of DARS2 and the clinical characteristics such as gender,age,smoking history and pathological stage was also analyzed.Further by constructing stable lung adenocarcinoma cell lines A549 and H1299 with DARS2 over-expression through through plasmid transfecting and packaging by lentivirus,the effects of DARS2over-expression on the proliferation,apoptosis,migration,invasion and other biological behaviors of lung adenocarcinoma A549 and H1299 cells were detected by CCK-8 method,flow cytometry and Transwell to explore the biological function of DARS2 in lung adenocarcinoma preliminarily.Results: The TCGA data analysis results in the first part show that,compared with the control group,the expression of DARS2 was significantly increased in the tumor group.DARS2 expression level is the factor influencing the survival of patients with lung adenocarcinoma.The expression of DARS2 detected by q RT-PCR and Western blot also showed that the expression level of DARS2 in lung adenocarcinoma tissues was higher than that in the para-carcinoma tissues.The vitro cell experiments of the second part showed that over-expression of DARS2 promoted the proliferation of lung adenocarcinoma cell lines A549 and H1299,inhibited the apoptosis of A549 and H1299 cells,and enhanced the migration and invasion ability of A549 and H1299 cells.Conclusion: In this study,we found that the expression of DARS2 was increased in lung adenocarcinoma tissues,and over-expression of DARS2 was a risk factor for the prognosis of lung adenocarcinoma patients.The lung adenocarcinoma patients with high expression level of DARS2 had a lower survival rate than those with low expression level of DARS2.Over-expression of DARS2 can promote the proliferation of A549 and H1299 cells,inhibit the apoptosis of A549 and H1299 cells,and enhance the migration and invasion ability of A549 and H1299 cells in vitro experiment.This study suggests that DARS2 may play an important role in the occurrence,development,invasion and metastasis of lung cancer.