Citrate silver nanoparticles modulate estrogen signaling in estradiol-supplemented ER-positive breast cancer cells.

Breast cancer remains the most common type of cancer affecting women. The estrogen receptor status of a tumor defines the therapeutic approach, which often includes endocrine treatment. Therefore, identifying potential endocrine-disrupting chemicals is of great importance. In this study, we cultured MCF-7 cells supplemented with 17β-estradiol and treated them with silver and polystyrene nanoparticles. We measured the impact of nanoplastics on silver nanoparticle-induced modulation of basic cellular processes. Additionally, we assessed the significance of estrogen signaling in the observed changes induced by these nanomaterials and compared our observations with results obtained on estrogen-deprived MCF-7 cells and ER-negative SK-BR-3 cell line. We observed an induction of proliferation in cells treated with silver nanoparticles (AgNPs). In contrast, treatment with citrate silver nanoparticles (AgNPcit) at the same concentration induced cytotoxicity. Polystyrene nanoparticles (PSNPs) modulated the observed effects of silver nanoparticles in a size-dependent manner. Both AgNPs and AgNPcit downregulated the expression of GPER1. Treatment with nanomaterials also led to the modulation of genes linked to estrogen signaling, such as FOS, MYC, CAV1, and EGR3. Our results suggest that the surface chemistry of silver nanoparticles may facilitate their ability to modulate estrogen signaling and interact with the estrogen receptor. Furthermore, the nanoplastics pollution may influence the cytotoxicity of silver nanoparticles. This paper highlights the importance of endocrine research in breast cancer, particularly within the context of nanoplastics pollution and the use of nanotechnology in breast cancer treatment.