Phthalates,
phthalic acid esters, are widely used as
plasticizers to produce polymeric materials in industrial production of plastics and daily consumable products. Animal studies have shown that
di(2-ethylhexyl)phthalate (
DEHP) may cause toxic effects in the rat brain. In the present study, chronic exposure to
DEHP (0.1-100μM) caused dose-dependent cell death via the activation of
caspase-3 in
neuroblastoma cells. Intriguingly, this harmful effect was prevented by the pan-
histone deacetylase (
HDAC) inhibitor trichostatin A, by the class II
HDAC inhibitor MC-1568, but not by the class I
HDAC inhibitor MS-275. Furthermore,
DEHP reduced specificity
protein 3 (Sp3) gene expression, but not Sp3
mRNA, after 24 and 48h exposures. However, Sp3
protein reduction was prevented by pre-treatment with MC-1568, suggesting the involvement of class II HDACs in causing this effect. Then, we investigated the possible relationship between
DEHP-induced neuronal death and the post-translational mechanisms responsible for the down-regulation of Sp3. Interestingly,
DEHP-induced Sp3 reduction was associated to its deacetylation and polyubiquitination. Co-immunoprecipitation studies showed that Sp3 physically interacted with HDAC4 after
DEHP exposure, while HDAC4 inhibition by antisense
oligodeoxynucleotide reverted the
DEHP-induced degradation of Sp3. Notably, Sp3 overexpression was able to counteract the detrimental effect induced by
DEHP. Taken together, these results suggest that
DEHP exerts its toxic effect by inducing deacetylation of Sp3 via HDAC4, and afterwards, Sp3-polyubiquitination.