Growth-promoting effect of bisphenol A on neuroblastoma in vitro and in vivo

PurposeTo investigate the effect and mechanism of bisphenol A (BPA), one of the main environmental endocrine disruptors, on the proliferation of human neuroblastoma cells.MethodsIn vitro, cultured SK-N-SH cells were treated with 17β-estradiol (E2; 1 ng/mL), BPA (2 μg/mL) with or without estrogen receptor antagonist ICI182,780 (10−6 mol/L). Viable cell number, DNA proliferation index, and expression of cyclin-dependent kinase 4 and cyclin D1 were assessed by absorbance reading, flow cytometry, and western blotting, respectively. In vivo, ovariectomized nude mice bearing SK-N-SH tumors were administered by gavage with E2 (500 μg/kg per day, n = 11), BPA (200 mg/kg per day, n = 10), or vehicle (n = 9) for 18 days. Mice body weight, tumor volume and weight were examined every 3 days. Tumor microvessel density, proliferating cell nuclear antigen and vascular endothelial growth factor expression were evaluated by immunohistochemical staining or western blotting.ResultsIn vitro, the BPA group had 20% higher number of viable cells, 70% higher proliferation index (both P < .01), and higher expression of cyclin-dependent kinase 4 and cyclin D1 than the nontreated group. In vivo, the BPA group had over 50% higher gross tumor volume, tumor weight, microvessel density, proliferating cell nuclear antigen (P < .05 or .01), and higher vascular endothelial growth factor protein expression than the mock control group. Both in vitro and in vivo BPA effects were comparable with those by E2. ICI182,780 effectively abolished the promoting effect for both.ConclusionsBisphenol A can promote the growth of neuroblastoma to a level similar to that of E2. Estrogen receptor–dependent pathway and angiogenesis may contribute to the underlying mechanisms.