Abstract: This study was conducted to identify gene expression profile changes associated with β-estradiol (E2) treatment in U2OS osteosarcoma cells by high-throughput RNA sequencing (RNA-seq). Two U2OS cell samples treated with E2 (15 µmol/L) and two untreated control U2OS cell samples were subjected to RNA-seq. Differentially expressed genes (DEGs) between the groups were identified, and main biological process enrichment was performed using gene ontology (GO) analysis. A protein–protein interaction (PPI) network was constructed using Cytoscape based on the Human Protein Reference Database. Finally, NFKB1  expression was confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). The map ratios of the four sequenced samples were >65%. In total, 128 upregulated and 92 downregulated DEGs were identified in E2 samples. After GO enrichment, the downregulated DEGs, such as AKT1 , were found to be mainly enriched in cell cycle processes, whereas the upregulated DEGs, such as NFKB1 , were involved in the regulation of gene expression. Moreover, AKT1 (degree =117) and NFKB1 (degree =72) were key nodes with the highest degrees in the PPI network. Similarly, the results of qRT-PCR confirmed that E2 upregulated NFKB1  expression. The results suggest that E2 upregulates the expression of NFKB1 , ATF7IP , and HDAC5 , all of which are involved in the regulation of gene expression and transcription, but downregulates that of TCF7L2 , ALCAM , and AKT , which are involved in Wnt receptor signaling through β-catenin and morphogenesis in U2OS osteosarcoma cells.
Keywords: differentially expressed genes, Wnt receptor signaling, β-catenin, protein-protein interaction network