Enantioselective Induction of Cytotoxicity by <i>o</i>,<i>p</i>′‑DDD in PC12 Cells: Implications
of Chirality in Risk Assessment of POPs Metabolites
- Publication date
- Publisher
Abstract
The
increased release of chiral persistent organic pollutants (POPs)
into the environment has resulted in more attention to the role of
enantioselectivity in the fate and ecotoxicological effects of these
compounds. Although the enantioselectivity of chiral POPs has been
considered in previous studies, little effort has been expended to
discern the enantiospecific effects of chiral POPs metabolites, which
may impede comprehensive risk assessments of these chemicals. In the
present study, <i>o</i>,<i>p</i>′-DDD,
the chiral metabolite of <i>o</i>,<i>p</i>′-DDT,
was used as a model chiral metabolite. First, a preferential chiral
separation at 100% ethanol was employed to obtain a pure enantiomer.
The enantioselective cytotoxicity of <i>o</i>,<i>p</i>′-DDD in rat cells (PC12) was evaluated by detecting activation
of the cellular apoptosis and oxidative stress systems and microarray
analysis. We have documented for the first time that <i>R</i>-(+)-<i>o</i>,<i>p</i>′-DDD increases
apoptosis by selectively disturbing the oxidative system (enzymes
and molecules) and regulating the transcription of Aven, Bid, Cideb
and Tp53. By comparing the data from the present study to data derived
from the parent compound, we concluded that the <i>R</i>-enantiomer is the more detrimental stereostructure for both <i>o</i>,<i>p</i>′-DDT and <i>o</i>,<i>p</i>′-DDD. This observed stereostructural effect is
in line with the structure–activity relationship formulated
at other structural levels. Biological activities of the chiral metabolites
are likely to occur in the same absolute configuration between chiral
POPs and their metabolites provided that they have the similar stereostructures