Whole transcriptome sequencing and competitive endogenous RNA regulation network construction analysis in benzo[a]pyrene-treated breast cancer cells

Breast cancer is the most common malignant tumor in women worldwide, and environmental pollutants are considered to be risk factors. Currently, most studies into benzo[a]pyrene (B[a]P)-induced breast cancer focus on biological effects such as proliferation, invasion, and metastasis, DNA damage, estrogen receptor (ER)-related molecular mechanisms, oxidative damage, and other metabolic pathways. This study aims to provide insights into the role of B[a]P in breast cancer development through RNA-seq and bioinformatics analysis and construction of a competing endogenous RNA (ceRNA) regulatory network. By analyzing RNA-seq results, we identified 144 differentially-expressed circRNAs, 69 differentially-expressed lncRNAs, 20 differentially-expressed miRNAs, and 212 differentially-expressed mRNAs. Following on, we analyzed the gene ontology (GO) and KEGG enrichment functions of the differentially-expressed RNAs. In addition, the protein-protein interaction (PPI) network was mapped for differentially-expressed mRNAs. Subsequently, we constructed ceRNA networks, one of which consisted of 45 dysregulated circRNAs, 11 miRNAs, and 9 mRNAs, and a second consisted of 40 lncRNAs, 11 miRNAs, and 9 mRNAs. Finally, 6 circRNAs, 4 lncRNAs, 1 miRNA, and 4 mRNAs were randomly selected for quantitative real-time PCR verification. PCR results were further verified by Western blotting assays. These results show that the expression level of differentially-expressed RNA was consistent with the sequencing data, and the Western blotting results were highly consistent with the PCR results, confirming that the sequencing result was very reliable. This study systematically explores the ceRNA atlas of differentially-expressed genes related to B[a]P exposure in breast cancer cells, providing new insights into mechanisms of environmental pollutants in breast cancer.