Screening of key regulatory microRNAs in medullary thyroid carcinoma based on microRNA expression chips

Abstract

Objective To find key miRNAs and their target genes in thyroid medullary carcinoma by studying the microRNAs (miRNAs) expression profiling of cancer and normal tissues. Methods The raw data of miRNA expression profiling (GSE40807) were downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed miRNAs were first compared between samples from the two groups, then the functions of these target genes and their metabolic pathways were analyzed. The interaction networks among these target genes and the regulatory networks between target genes and transcription factors were constructed. Results There were 21 miRNAs which were significantly varied in thyroid medullary carcinoma compared to normal thyroid. Among them, 18 miRNAs were up-regulated, and 3 miRNAs were down-regulated. A total of 336 miRNA and target gene pairs were obtained from 11 predicted target databases. STRING protein interaction network analysis of these target genes revealed 230 nodes and 491 relationship trees. In addition, we reported 7 transcription factors, 156 nodes and 300 relation trees by conducting TF prediction and regulation network construction for these target genes. Conclusion We systematically analyzed the miRNA expression profiling and related target genes in thyroid medullary carcinoma by bioinformatics methods and screened some relevant regulatory factors such as miR-124, miR-7 and miR-129-5. This study will provide effect direction and foundation for further research. Key words: Medullary thyroid carcinoma; Target genes; MicroRNA chip