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

Abstract

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 causemetastasis. Environmental endocrine disruptors (EED) are recentlyidentified risk factors associated with various human diseasesincluding malignant tumors. Our previous studies have implicated therole of di(2-ethylhexyl) phthalate (DEHP) and bisphenol A (BPA), two ofthe most common EED, in neuroblastoma cell proliferation. Here, wefurther investigated the effects of DEHP, BPA as well as 17beta-estradiol (E-2) on the invasion and metastasis of humanneuroblastoma SK-N-SH cells in vitro. SK-N-SH cells expressed estrogenreceptor (ER)-beta, matrix metalloproteinases-2 (MMP-2), MMP-9 andtissue inhibitor of matrix metalloproteinase-2 (TIMP-2) at readilydetectable levels. 50 mu M DEHP, 0.1 mu M BPA and 10 mu M E, exposureall resulted in enhanced motility and invasiveness of SK-N-SH cells(P<0.001), elevated expression of MMP-2 and MMP-9, and decreasedexpression 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, orE-2-induced cell migration and invasion, as well as the disregulationof MMP-2, MMP-9 and TIMP-2 expression. ICI182,780 may have workedthrough abolishing Akt (Ser473) phosphorylation. In conclusion, DEHP,BPA, and E-2 potently promote invasion and metastasis of neuroblastomacells through overexpression of MMP-2 and MMP-9 as well asdownregulation of TIMP-2. ER-dependent pathway and PI3K/Akt pathway areinvolved, which may become potential therapeutic targets forneuroblastoma treatment.