ヒトのHepaRG細胞が遺伝子毒性発がん物質に長期にわたって被曝した後に発生した変異の蓄積
Xiaoqing Guo1, Ji-Eun Seo1, Jaime Miranda-Colon1
1Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.
まとめ
ヘパRG細胞におけるN- ニトロジメチラミン (NDMA) の長期的曝露は,特に3D培養において,変異の頻度を増加させる. 試験期間が長ければ,化学物質のリスク評価のための in vitro 遺伝子毒性評価が改善されます.
科学分野:
- 毒理学と薬理学
- 細胞生物学と遺伝学
背景:
- 正確な化学リスク評価には,実際の暴露を模倣したヒト関連 in vitro モデルが必要です.
- 以前の研究では,短期性遺伝子毒性試験で細胞毒性による変異の検出が限られていた.
研究 の 目的:
- N-ニトロジメチラミン (NDMA) に7日および14日の曝露後に2Dおよび3DヘパRG細胞の変異蓄積を調査する.
- NDMA誘発性遺伝子毒性に対する治療期間と培養モデル (2D対3D) の影響を評価する.
主な方法:
- 2Dおよび3D球体で培養されたHepaRG細胞は,7日および14日の間,異なる濃度のNDMAにさらされました.
- マルチエンドポイントアプローチでは DNAの損傷,マイクロ核の形成,および変異の頻度が測定されました.
- 定量分析にはベンチマーク濃度 (BMC) モデルを使用した.
主要な成果:
- NDMAの曝露は,濃度と持続時間によるDNA損傷と変異頻度の増加につながった.
- 14日間の曝露は7日間の曝露より高い突然変異の頻度を引き起こし,細胞毒性は限られた (<30%).
- 3D HepaRGの球体は2D培養と比較して,著しく高い変異頻度と低いBMC値を示した.
- 主な突然変異はT→C変異でした.
結論:
- 長期暴露 (14日) は,ヘパRG細胞における in vitro 遺伝子毒性試験の感度を増大させる.
- 3D HepaRG スフェロイドは,2D カルチャーと比較してNDMA誘発変異を検出するためのより敏感なモデルを提供します.
- より正確な化学リスク評価のために,より長い曝露期間と3Dモデルを使用することを支持しています.
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