MicroRNA Expression Profiling Involved in Borax-Induced Anti-Tumor Effect Using Gene-Chip Analysis

Abstract Background Borax has been shown to have potential therapeutic benefits. However, the mechanisms underlying borax-induced anti-tumor effect remain to be further elucidated. MicroRNAs (miRNAs) may play key roles in cellular processes such as tumor progression and cell apoptosis. Objective The present study aimed to investigate whether miRNAs were involved in borax-mediated anti-tumor effect using gene-chip analysis. Methods Total RNA was extracted and purified from HepG2 cells treated with 4 mM borax for 2 or 24 h. The samples underwent microarray analysis using a human miRNA Array. Differentially expressed miRNAs were analysed by volcano plot and heatmap, and were validated using quantitative PCR. PPI network was then established, and hub genes were identified via Cytoscape software. Results Exposure to borax for 2 or 24 h significantly altered the expression level of miRNAs in HepG2 cells, and 4 or 14 miRNAs were upregulated, respectively, while 3 were downregulated compared with the findings in the control group (≥2 fold-change, P<0.05). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed that the target genes of the differentially expressed miRNAs in HepG2 cells predominantly participated in the MAPK, TGF-β and NF-κB signaling pathways in the 2-h borax treatment group, while they were involved in the Ras signaling pathway, forkhead box O signaling pathway and cellular senescence in the 24-h treatment group. Construction and analysis of PPI network showed that NACC2, CACNB1 and FZD6, CDK6, BCL-2, IGF1R, BTG2, AGO2, DLGAP3 were recognized as hub genes with the highest connectivity degrees in the 2-h or 24-h, respectively. Conclusion The results indicate that the borax-induced antitumor effect may be associated with alterations in miRNAs. Furthermore, we established a potential tumor-related miRNA-mRNA regulatory network, which explores a comprehensive understanding of the molecular mechanisms and provides novel therapeutic targets for liver cancer.