Identifying of a Novel miR-98-5p/IGF1 Axis Contributes the Pathogenesis of Breast Cancer Using Comprehensive Bioinformatic Analyses Methods and Experiments Validation

Abstract

Background: Breast cancer (BC) is a huge threat for the health of women worldwide. Although the numerous microRNAs (miRNA) have been identified to be aberrantly expressed in BC, the construction of a comprehensive miRNA-messenger RNA (mRNA) network is still needed. This study was aimed to identify BC-associated miRNAs through analyzing microarray datasets obtained from GEO database and to construct a miRNA-mRNA network for BC. Methods: Limma package was used to identify differentially expressed miRNAs (DEMs) in microarray datasets. Genes targeted by DEMs were analyzed with mirTarBase. Gene Ontology and pathway enrichment analysis for the predicted target genes were performed at DAVID. Correlation of DEMs and target genes was analyzed at ENCORI. Based on these results, a miRNA-mRNA regulatory network was constructed. Results: A total of 17 overlapping DEMs were identified at these two microarray datasets. Expression of DEMs in BC were further validated by ENCORI. By utilizing miRTarBase, a total of 167 target genes for DEMs were obtained. 10 hub genes (AKT1, MYC, VEGFA, CCND1, PTEN, IL6, CASP3, KRAS, IGF1, ESR1) were identified after network analysis at STRING and CytoScape. Through analyzing the effects of hub genes on overall survival of BC patients and correlation of DEMs and hub genes, we found hsa-miR-98-5p/IGF1 axis may play a crucial role in BC progression. The connections of hsa-miR-98-5p and IGF1 were further validated by luciferase activity reporter assay and functional assays. Conclusion: In this work, a miRNA-mRNA network related to BC progression was built, and identified one important miRNA-mRNA axis in BC.