Comparison of transcriptome expression alterations by chronic exposure to low-dose bisphenol A in different subtypes of breast cancer cells

The impacts of chronic bisphenol A (BPA) exposure suspected to be a potential risk factor for breast cancer progression are not thoroughly understood in different subtypes of breast cancer cells (BCCs). This study aimed to compare the differentially expressed genes (DEGs) and biological functions in MCF-7 (luminal A), SK-BR3 (HER2-enriched) and MDA-MB-231 (triple-negative) cells exposed to BPA at an environmentally human-relevant low dose (10(-8) M) for 30 days, by using the approach of RNA sequencing and online informatics tools. BPA-exposure resulted in 172, 137, and 139 DEGs in MCF-7/BPA, SK-BR3/BPA, and MDA-MB-231/BPA, respectively. The significantly enriched gene ontology terms of DEGs in each cell were different: cellular response to gonadotropin-releasing hormone, negative regulation of fibrinolysis, choline metabolism, glutamate signaling pathways and coagulation pathway in MCF-7/BPA; positive regulation of inflammatory response and VEGF/VEGFR signaling pathways in SK-BR3/BPA; negative regulation of keratinocyte proliferation and HIF signaling pathways in MDA-MB-231/BPA cells. The immune network analysis of DEGs across the breast cancer cells indicated NKT, NK and T cell activation and dendritic cell migration by regulating the expression of immunomodulatory genes. High expression of IL19, CA9 and SPARC identified in MCF-7/BPA, SK-BR3/BPA, and MDA-MB-231/BPA are detrimental gene signatures to predict poor overall survival in luminal A, HER2-enriched and triple-negative breast cancer patients, respectively. These findings indicate chronic BPA exposure has dissimilar impacts on the regulation of gene expression and diverse biological functions, including immune modulation, in different subtypes of BCCs.