Application of bioinformatics in screening of miRNA biomarkers in triple-negative breast cancer / 吉林大学学报(医学版)

ABSTRACT

Objective: To analyze the differentially expressed miRNAs in triple negative breast cancer (TNBC) and predict their target genes through The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, to explore their biological functions and molecular mechanisms, and to find the prognosis-related targets of TNBC. Methods: A total of 343 miRNAs expression data related to breast cancer tissue and adjacent tissue were downloaded from the TCGA database to screen the differentially expressed miRNAs in breast cancer and adjacent tissue. The GEO database was used to validate the expressions of miRNAs in 26 kinds of cell lines of TNBC and the changes in serum miRNAs in the TNBC patients before and after chemotherapy. The target gene function of candidate miRNAs was analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway enrichment and protein interaction network. Results: The TCGA database showed that the expression level of miR-21-5p in breast cancer tissue was significantly higher than that in adjacent tissue (logFC = 5. 557, P<0. 01). The results of GEO database showed that the expression level of miR-21-5p increased in TNBC cell line was significantly higher; the relative expression levels in more than 20 kinds of cell lines from 26 TNBC cell lines were over 70 000, and the expression level of miR-21-5p in the TNBC patients after combined chemotherapy was significantly decreased (logFC= -5.07, P<0. 01). The GO analysis showed that miR-21-5p played a regulatory role in DNA replication, transcription and vascular remodeling. The KEGG enrichment analysis showed that miR-21-5p mainly affected the occurrence and development of TNBC through mitogen activated protein kinase (MAPK) and transforming growth factor-β (TGF-J3) pathways. Conclusion: miR-21-5p is up-regulated in TNBC tissue and plays a positive regulatory role in the progression of TNBC, which may be a key biomarker for identifying the prognostic extent of TNBC. DUSP8 may be involved in the regulation of the occurrence and development of TNBC as a target gene of miR-21-5p.