Environmental endocrine disruptors promote invasion and metastasis of SK-N-SH human neuroblastoma cells

Neuroblastoma (NB) is the most common pediatric extracranial cancer. Metastasis is the main cause of mortality in NB patients. Currently, little is known about the risk factors and their mechanisms that cause metastasis. Environmental endocrine disruptors (EED) are recently identified risk factors associated with various human diseases including malignant tumors. Our previous studies have implicated the role of di(2-ethylhexyl) phthalate (DEHP) and bisphenol A (BPA), two of the most common EED, in neuroblastoma cell proliferation. Here, we further investigated the effects of DEHP, BPA as well as 17 beta-estradiol (E-2) on the invasion and metastasis of human neuroblastoma SK-N-SH cells in vitro. SK-N-SH cells expressed estrogen receptor (ER)-beta, matrix metalloproteinases-2 (MMP-2), MMP-9 and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) at readily detectable levels. 50 mu M DEHP, 0.1 mu M BPA and 10 mu M E, exposure all resulted in enhanced motility and invasiveness of SK-N-SH cells (P<0.001), elevated expression of MMP-2 and MMP-9, and decreased expression of TIMP-2 (P<0.01). Furthermore, phosphorylation of Akt (Ser473) was also induced following the exposure (P<0.01). Importantly, both ER antagonist ICI182,780 and phosphoinositide 3-kinase (PI3K) specific inhibitor LY294002 significantly inhibited the DEHP, BPA, or E-2-induced cell migration and invasion, as well as the disregulation of MMP-2, MMP-9 and TIMP-2 expression. ICI182,780 may have worked through abolishing Akt (Ser473) phosphorylation. In conclusion, DEHP, BPA, and E-2 potently promote invasion and metastasis of neuroblastoma cells through overexpression of MMP-2 and MMP-9 as well as downregulation of TIMP-2. ER-dependent pathway and PI3K/Akt pathway are involved, which may become potential therapeutic targets for neuroblastoma treatment.