CircIGFIR Inhibits The Metastasis And Invasion Of Lung Adenocarcinoma

BACKGROUND Lung cancer is the most common malignant tumor in China and is the leading cause of death in cancer patients.Non-small cell lung cancer accounts for more than 80% of lung cancer.In recent years,the incidence of lung adenocarcinoma has gradually increased,becoming the most commonly diagnosed type of lung cancer tissue in adult.Although individualized treatment of lung adenocarcinoma has achieved some results,the overall survival of patients with advanced lung adenocarcinoma have not been more than 2 years,and the five-year survival rate is about 18%.The choice for advanced-stage patient treatment are also narrow.Therefore,we urgently need to find effective molecular biomarkers and new therapeutic targets for lung adenocarcinoma.Circular RNA is a kind of non-linear non-coding RNA with closed loop structure formed by special splicing mechanism.In this study,Sanger sequencing,RT-PCR and cell transfection,Wound Healing and Transwell method techniques were used to evaluate the effects of circIGF1 R on lung adenocarcinoma.The RNA-seq and bioinformatics methods were utilized to analyze the potential mechanism of circIGF1 R in the invasion and metastasis of lung adenocarcinoma and to determine the therapeutic target of lungadenocarcinoma.METHODS 1.The circIGF1 R expression was detected in lung cancer cell lines(A549,Calu-1,H1975,PC9,H1299)by using circular primers(primer cross-cyclization site design)and QPCR method;2.The RT-PCR method was utilized to evaluate the clinical value of circIGF1 R in 50 clinical LUAD samples;3.CircIGF1 R was overexpressed in A549 cells by transfection method,and then the Wound Healing and Transwell experiments were performed to detect the functional effects on A549 cell line;4.RNA-seq sequencing technology was performed in circIGF1R-overexpressed A549 cell line and control A549 cell line,and bioinformatics method was used to further speculate the potential regulation mechanism of circIGF1 R in LUAD.RESULTS 1.The expression of circIGF1 R was confirmed in all lung cancer cell lines,and circIGF1 R showed the highest expression in A549 lines.Sanger sequencing confirmed the splicing and cyclization site of circIGF1 R in A549 cell line,indicating the objective existence of circIGF1R;2.The expression of circIGF1 R in LUAD tissues was significantly lower than that of adjacent lung tissues.The expression level of circIGF1 R was significantly decreased in the LUAD patients with smoking history,advanced tumor stages and lymph node metastasis;3.The Wound Healing and Transwell assay suggested that overexpression of circIGF1 R can inhibit the migration and invasion of LUAD cells.4.Based on RNA-seq results,we found that circIGF1 R regulates 20 pathways closely related to cancer progression and the immune response,suggesting that circIGF1 R may regulate immune response and thus affects the metastasis and invasion of LUAD.CONCLUSION 1.The objective existence of circIGF1 R was preliminarily proved in lung cancer cell lines.2.CircIGF1 R plays a role in tumor suppressionof LUAD;3.Wound healing and Transwell assay showed the overexpression of circIGF1 R can inhibit the migration and invasion of LUAD cells;4.RNA-seq results suggest that circIGF1 R may regulate immune pathways and thus affect the metastasis and invasion of LUAD.