Expression And Biological Function Of Hsa-microRNA-301a/b In Plasma Of Patients With Non-small Cell Lung Cancer

Background:Lung cancer has the highest morbidity and mortality of cancer diseases in China,in which non-small cell lung cancer accounts for 80%of lung cancer.The prognosis of NSCLC patients remains poor because of lack of timely diagnosis and treatment.The 5-year overall survival rate ranged from 2%to 17%.When lung cancer is detected in early stages,the 5-year survival rate could be increased to 80%.Because there are no obvious symptoms in early NSCLC patients,most lung cancer patients only seek medical treatment when NSCLC is already in the middle and late stages.In recent years,with the discovery of microRNAs and the relationship between mi RNAs and tumorigenesis and development,the possibility of using miRNAs as a means of diagnosis and treatment approach has become an increasing focus of research.mi RNA is involved in many biological processes,such as growth,proliferation,differentiation and apoptosis,and is closely related to a variety of human tumors,such as lung cancer,liver cancer,breast cancer,pancreatic cancer,and so on.Therefore,it is important to study the expression and function of miRNA in human tumors,which may lead to novel diagnosis,treatments for cancer.Objective:The expression level of mi RNA-301a/b in patients with NSCLC was detected using quantitative real-time PCR?qRT-PCR?,and the diagnostic significance of mi RNA-301a/b in NSCLC was discussed.The effect of miRNA-301a/b on the proliferation,cycle and apoptosis of human A549 lung cancer cell line was studied by transfection of mi RNA mimicides/inhibitor to up-regulate or down-regulate the expression of mi RNA-301a/b in A549 lung cancer cell line.Methods:?1?Peripheral blood of 55 patients with NSCLC and 34 healthy people were centrifuged.The plasma was isolated,the total miRNAs were extracted,and then reverse synthesis of cDNAs was carried out.The Ct value of mi RNA-301a/b was determined by qRT-PCR reaction and the relative expression of miRNA-301a/b in plasma samples of NSCLC patients was calculated by 2^-??Ct.?2?The A549 lung cancer cells were transfected with miRNA mimicsr-inhibitor,and the expression of miRNA-301a/b was up-regulated or down-regulated,and the related functions were detected.Effects of up-regulation or down-regulation of miRNA-301a/b on proliferation,cell cycle and apoptosis of lung cancer cells were analyzed by means of CCK-8,PI staining,Annexin?and PI double staining flow cytometry.Results:?1?Compared with the healthy control group,the relative expression level of mi RNA-301a/b in the plasma of NSCLC patients was significantly higher?P<0.01?.There was no correlation between the relative expression of plasma miRNA-301a/b and the clinicopathological features of NSCLC patients,but a significant correlation with clinical stage was found?P=0.008 and P=0.044?.The areas under the curve of plasma mi RNA-301 a,RNA-301b and combined diagnosis of NSCLC were 0.801,0.887 and 0.891,respectively.mi RNA-301 a,RNA-301b and combined diagnosis of adenocarcinoma were 0.795,0.876and 0.880,respectively.mi RNA-301 a,RNA-301b and combined diagnosis ofsquamous cell carcinoma were 0.810,0.906 and 0.910,respectively.?2?The expression level of mi RNA-301a/b in miRNA mimics/inhibitor group was significantly different from that in NC group?P<0.05?.After transfection of miRNA mimics into A549 lung cancer cell line,cell proliferation was promoted.After transfection of miRNA inhibitor,cell cycle and apoptotic flow cytometry were used to detect the cell cycle.The results showed that the proportion of G₀/G₁ phase and S phase were increased,the proportion of G₂/M phase was decreased,and lung cancer cells showed significant apoptosis.Conclusion:The high expression of miRNA-301a/b in NSCLC and its correlation with stage of NSCLC patients can be used to predict NSCLC.High expression of miRNA-301a/b in A549 cells was found to significantly improve cell proliferation.Low expression of mi RNA-301a/b in A549 cells caused cell cycle arrest in G₁/S phase,and also significant apoptosis in A549 cells.It suggests that miRNA-301a/b participates in the development of NSCLC as a oncogene and has the potential to be a diagnostic marker for NSCLC.