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Assessment of the In Vitro Phosphatidylinositol Glycan Class A (PIG-A) Gene Mutation Assay Using Human TK6 and Mouse Hepa1c1c7 Cell Lines

  • 0Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA.
Journal of Xenobiotics +

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September 23, 2024

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September 23, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Environmental chemicals can cause gene mutations. This study compared mutagenicity of ethyl methane sulfonate (EMS) and polycyclic aromatic hydrocarbons (PAHs) using the PIG-A gene mutation test, finding cell line and viability assay choice impacts results.

Area Of Science

  • Toxicology
  • Genetics
  • Biochemistry

Background

  • Gene mutations from environmental chemicals are linked to diseases like cancer.
  • The X-linked phosphatidylinositol glycan class A (PIG-A) gene is a crucial target for genetic toxicity assays.
  • Different organisms and cell lines exhibit varied responses to genotoxic agents.

Purpose Of The Study

  • To compare the mutagenic potential of a direct mutagen (ethyl methane sulfonate, EMS) and pro-mutagens (polycyclic aromatic hydrocarbons, PAHs).
  • To evaluate the suitability of the in vitro PIG-A gene mutation test in metabolically active (Hepa1c1c7) and limited-metabolism (TK6) cell lines.
  • To assess the impact of different cell viability assays (MTT and propidium iodide staining) on mutagenicity outcome.

Main Methods

  • An in vitro PIG-A gene mutation test was conducted using murine hepatoma Hepa1c1c7 and human TK6 cell lines.
  • Cells were exposed to ethyl methane sulfonate (EMS) and polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene (B[a]P), 5-methylcholanthrene (5-MC), and chrysene.
  • Cell viability was determined using MTT assay and propidium iodide (PI) staining with flow cytometry; PI-based cytotoxicity was prioritized due to MTT assay limitations.

Main Results

  • Spontaneous mutation rates were 1.87 (TK6) and 1.57 (Hepa1c1c7) per million cells per cell cycle.
  • EMS significantly increased mutation frequencies in TK6 cells (36-47 per million).
  • B[a]P did not increase mutation frequency in TK6 cells, but PAHs and EMS induced mutations in Hepa1c1c7 cells, with varying frequencies (29-81 per million).

Conclusions

  • The choice of cell line and cytotoxicity assay significantly influences the outcome of the PIG-A mutagenesis assay.
  • Metabolic activation plays a role in the mutagenicity of PAHs.
  • Accurate assessment of genotoxicity requires careful consideration of experimental design, including cell line selection and viability testing methods.

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