Study Of MiR-23b By Targeting SET8 In Lung Adenocarcinoma

ObjectiveLung cancer is a common malignant tumor in the world with the highest morbidity and mortality. At present, the 5-year survival rate of patients with lung cancer is still low, at just 15%. The etiology and mechanism of lung cancer is complex, and both genetic and epigenetic factors involved. Not encoding protein, as a kind of small molecule RNA, microRNA can be involved the transcription regulationin of gene expression. The study of microRNA and its target genes is helpful for us to explore new diagnostic and therapeutic targets for lung cancer.miR-23 b differentially expressed in female non-smoking lung adenocarcinoma(ADC)by microRNA expression profiling, so we speculate that it plays a certain role in the occurrence and development of ADC. In this study, the effect of miR-23 b was predicted by bioinformatics and luciferase reporter gene SET8; The effect of miR23 b on the development and progression of ADC was preliminarily explored by cell function test; Studying the expression of SET8 and its influence on the survival and prognosis of ADC in the population level. Our study provided the basis for the etiology and treatment of ADC.Methods1. Through bioinformatics screening and luciferase reporter gene assay, we verified SET8 targeted by miR-23 b. A549, H1299 cell lines were selected to carry out the cell function tests. MTT cell proliferation, cell cycle, migration and invasion assays were used to analysis the effects of miR-23 b overexpression on the proliferation, cell cycle,migration and invasion, confirming the regulation of miR-23 b targeted SET8 on ADC.2. Tissue microarray(TMA) was made with 140 ADC tissues and 80 adjacent tissues collected from Tianjin Medical University Cancer Institute and Hospital. The expression of SET8 was studied by immunohistochemical staining. Clinical informations were collected through access to medical records, and survival situation obtained by telephone follow-up to analysis the ralations between the expression of SET8 and the pathogenesis and prognosis of patients with ADC.The expression of SET8 in ADC was tested by wlicoxon test, and the survival situation was based on log-rank test and multivariate Cox regression analysis.Results1. The expression of mi R-23 b in ADC tissues was significantly lower than that inpaired noncancerous tissues, and the difference was statistically significant(P≤0.001).Consistent with miR-23 b expression in plasma of women non-smoking lung adenocarcinoma, so we think miR-23 b could be a suppressor gene in patients with ADC.2. Luciferase reporter assay showed that miR-23 b combined with SET8 by two binding sequences. Mi R-23 b can negatively regulate the expression of SET8 in ADC from mRNA and protein level. The expression of miR-23 b can inhibit cell proliferation, regulate cell cycle and inhibit cell migration and invasion.3. The protein expression level of SET8 increased in ADC(P≤0.001), and SET8 is a potential carcinogenic gene. There is no correlation between SET8 expression and the clinical characteristics. Survival analysis showed that high expression of SET8 is a worse prognosis of adenocarcinoma(OS:P=0.025;DFS:P=0.020). Hierarchical analysis confirmed that the patients with high SET8 protein expression had poor prognosis in men, lung disease history, history of family of cancer, early stage of tumor infiltrating and without lymph node metastasis. Cox regression analysis showed that SET8 is an independent risk factor in ADC.ConclusionMiR-23 b may function as tumor suppressor through targeted regulation of SET8 in ADC. As a carcinogenic gene regulated by miR-23 b, SET8 expression level is associated with the pathogenesis and prognosis of ADC. The high expression of SET8 is an independent prognostic risk factor. Its action mechanism still needs to be further explored.