Technology-Critical Element Exposure Reveals Divergent Toxicity in Different Human Cells Despite Comparable Uptake.

Area of Science:

• Environmental Science
• Toxicology
• Cell Biology

Background:

• Technology-Critical Elements (TCEs) are increasingly used, leading to environmental release and potential health concerns.
• Emerging evidence suggests TCEs possess significant toxicity, necessitating investigation into their biological effects.

Purpose of the Study:

• To investigate the biological effects of Indium oxide, Lanthanum nitrate hexahydrate, and Cerium(III) nitrate hexahydrate on human dermal fibroblasts (BJ) and hepatocarcinoma cells (HepG2).
• To assess TCE uptake, impact on cell viability, and cellular stress responses, including inflammation, oxidative stress, and membrane damage.

Main Methods:

• Exposure of BJ fibroblasts and HepG2 cells to selected TCEs.
• Quantification of TCE uptake, cell viability assays, and measurement of cellular stress markers.
• Analysis of differential susceptibility and correlation with antioxidant responses.

Main Results:

• Human dermal fibroblasts (BJ) exhibited vulnerability to TCEs, whereas HepG2 cells demonstrated high resistance, despite comparable TCE accumulation in both cell lines.
• Differential toxicity was strongly correlated with opposing antioxidant responses between the cell types.
• Low concentrations of cerium (III) nitrate stimulated HepG2 cell proliferation (up to 129% of control).

Conclusions:

• Toxicity of TCEs is not solely dependent on uptake magnitude, suggesting complex mechanisms of action.
• Findings highlight potential mechanistic hazards of low-level TCE exposure, particularly the proliferative effect of cerium nitrate on cancer cells.
• Further research in more complex biological models is warranted to fully understand the implications of TCE exposure.