Endocrine Disruption: Evaluation of the Estrogen Receptor Agonist and Antagonist Activity using the Stably Transfected Human Estrogen Receptor-α Transactivation Assay (ERα-CALUX® Cell Line)/Mn Metal Powder and MnCl2

This study investigated the ability of two Mn-containing materials, MnCl₂ and high-purity electrolytic manganese powder ((HPEMP), also known as Mn metal), to activate or block human estrogen receptor alpha (hERα) signaling using the ERα-CALUX® cell line in vitro.

A single valid ERα agonist and antagonist experiment was performed for each test material following a solubility analysis to determine suitable top concentrations. Milli-Q water (MQ) was used as vehicle.

Both materials were evaluated across eight concentrations from 1 nM to 1 mM, with actual Mn exposure from Mn metal being lower due to very low water solubility.

 Cytotoxicity was observed for MnCl₂ at 316 µM  and 1 mM under ERα agonist conditions and at 1 mM  under ERα antagonist conditions, while no cytotoxicity occurred for Mn metal, and cytotoxic concentrations were excluded from analysis. All assay acceptability parameters were met.

Overall, both MnCl₂ and Mn metal were considered negative in the ERα-CALUX agonist and antagonist experiments.