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Climacteric : the journal of the International Menopause Society

Lower concentrations of phthalates induce proliferation in human breast cancer cells.


PMID 24228746

Abstract

To explore the effect and pathway of phthalates on the growth of MCF-7 breast cancer cells. MCF-7 cells were treated with benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP) (10(-10)-10(-4) mol/l). After incubation for 24, 48, 72, and 92 h, the cells were harvested and extracted for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The proteins involving proliferative and apoptotic pathways were evaluated by Western blot analysis. MTT assay revealed cell toxicity at more than 10(-5) mol/l for DEHP and at 10(-4) mol/l for both BBP and DBP in MCF-7 cells. Cell proliferation was significantly increased at 10(-8)-10(-5) mol/l of BBP and DBP, and at 10(-8)-10(-6) mol/l of DEHP treatment. Proliferating cell nuclear antigen (PCNA) was substantially increased in cultures with DEHP (10(-8)-10(-6) mol/l), BBP (10(-8)-10(-5) mol/l), and DBP (10(-7)-10(-5) mol/l). Obvious increases in PI3K, p-AKT, and PCNA were noted in cultures with 17β-estradiol, BBP, DBP, and DEHP. Estrogen receptor α expression was also notably increased in treatment with estradiol, BBP, DBP, and DEHP. The present study demonstrates that, even at a very low concentration, BBP, DBP, and DEHP were not only still capable of inducing a proliferative effect through the PI3K/AKT signaling pathway but also displaying estrogenic activity. Therefore, the current reference doses for phthalates defined by governments should be further evaluated.