Nonylphenol induces proliferation of prostate epithelial cell line (PNT1a)

Nonylphenol (NP) belongs to Endocrine Disrupting Chemicals (EDCs) with xenoestrogenic activity, called xenoestrogens, abundantly present in the environment. NP is widely used as surfactants in industrial and agricultural applications and in plastic formulations. Its xenoestrogenic activity was demonstrated both in vitro and in vivo. However, there are only few studies on the NP effects on prostate cell lines. Estrogens play an important role in development and growth of the prostate and may cause some pathologies, including cancer. Since NP mimics endogenous estrogens, it could have a negative influence on prostate physiology. In this study we examined the effects of NP and 17β-estradiol (E2) on the proliferation of non tumorigenic prostate epithelial cell line (PNT1A) and their interaction with estrogen receptors. These effects were also studied in presence of selective estrogen receptor antagonist ICI182,780. We found that both NP and E2 stimulate PNT1A proliferation in a dose-dependent manner, but the NP effects were lower than E2. Immunofluorescence and western blot analyses revealed that both NP and E2 induce cytoplasm-nucleus translocation of ERα. The nuclear localization of ERα by E2 was already shown after 2h of treatment and only after 6h by NP. The inhibition of these effects by adding ICI182,780 was shown. Surprisingly, NP and E2 didn’t affect the localization of ERβ. These results suggest that NP stimulates PNT1A proliferation probably through the interaction with ERα that in turn is involved in the activation of some prostate cell cycle key regulators