Screening And Bioinformatics Analysis Of MicroRNA Microarray For Lung Adenocarcinoma

Objective:Lung cancer is one of the most common malignant tumors.Lung adenocarcinoma is the highest proportion of lung cancer,with high mortality and poor prognosis.MicroRNA(miRNA)is a small endogenous non-coding RNA with a length of about 18-25 nucleotides,miRNA can down-regulate tumor suppressor gene expression and up-regulate oncogene expression and participate in various cellular processes,such as cell proliferation,apoptosis,differentiation and metabolism.When we detected differentially expressed miRNAs between lung adenocarcinoma and normal tissues and made bioinformatics analysis of differentially expressed miRNAs which has research value,we can explore the function of miRNAs in the occurrence and development of lung adenocarcinoma and provide more ideas for the pathogenesis,diagnosis and treatment of lung adenocarcinoma.Method:After extracting total RNA from lung adenocarcinoma and normal tissues,we can use miRNA microarray technology to detect miRNA expression profiles which are related to lung cancer and normal lung tissues,and then,we select the differentially expressed miRNAs and use cluster analysis to analyse these miRNAs.As for the meaningful differentially expressed miRNAs,we use the way of qPCR verification to analyze its' relative expression levels and made a judge of whether the verification result is consistent with the result of chip detection;Finally,we choose the verified differentially expressed miRNAs to make bioinformatics analysis,which including GO enrichment analysis and KEGG enrichment analysis.Result:We use miRNA microarray found 24 miRNAs with significant differential expression(signal value >500,P value <0.05)in the lung adenocarcinoma tissues,among these differentially expressed miRNAs,12 miRNAs were up-regulated and 12 miRNAs were down-regulated.The heat map was used to visual present the up-and-down result of differentially expressed miRNAs.On the basis that the coefficient of variation(the CV value: the ratio of the standard deviation to the mean,expressed as a percentage,the formula is CV = SD/Mean X 100%)is satisfied with the requirement of less than 15%,we select four miRNAs(hsa-miR-4328,hsa-miR-664a-3p,hsa-miR-4284 and hsa-miR-625-5p)which have been scarcely studied but possess large differences in the field of lung cancer to make subsequent validation and enrichment analysis.The relative expression levels of four differentially expressed miRNAs reveal that hsa-miR-4328 is down-regulated from normal tissues to cancer tissues,while hsa-miR-664a-3p,hsa-miR-4284 and hsa-miR-625-5p are up-regulated from normal tissues to cancer tissues,and this verification result is consistent with the result of chip detection.The GO enrichment analysis of the four differentially expressed miRNAs show that these miRNAs have the function of binding protein and were involved in the formation of nucleus,they can also acts as DNA transcriptase;KEGG enrichment analysis of these four differential miRNAs revealed that these miRNAs can participate in multiple signal pathways such as RAP-1 and AMPK.Conclusion: 1.This study screened 24 differentially expressed microRNAs in lung adenocarcinoma tissues by microRNA chip technology.2.Quantitative PCR confirmed that hsa-miR-4328 was down-regulated and hsa-miR-664a-3p,hsa-miR-4284 and hsa-miR-625-5p were up-regulated in lung adenocarcinoma tissues compared with normal lung tissues.3.Bioinformatics analysis found that hsa-miR-4328,hsa-miR-664a-3p,hsa-miR-4284 and hsa-miR-625-5p are involved in biological processes such as binding proteins and nucleus,some of which have DNA transcriptase function and can also participate Multiple signal pathways such as RAP-1 and AMPK.