Restricted accessResearch articleFirst published online 2015-3
BDE-99 (2,2′,4,4′,5-pentabromodiphenyl Ether) Triggers Epithelial-mesenchymal Transition in Colorectal Cancer Cells via PI3K/Akt/Snail Signaling Pathway
The gut is in direct contact with BDE-99 (2,2′,4,4′,5-pentabromodiphenyl ether), one of the most abundant PBDE congeners in the environment and in human tissues. The objective of the present study was to investigate the effects of BDE-99 on colorectal cancer (CRC) cells.
Methods
The effects of BDE-99 on cell proliferation were measured by CCK-8 assay in the CRC cell line HCT-116. Wound healing and transwell migration/invasion assays were used to test the migration and invasion of CRC cells. Factors related to epithelial-to-mesenchymal transition (EMT) were measured by real-time PCR and Western blot analysis for mRNA and protein levels, respectively.
Results
BDE-99 was found to increase migration and invasion and trigger EMT in HCT-116 cells; EMT was characterized by cells acquiring mesenchymal spindle-like morphology and by increased expression of N-cadherin with a concomitant decrease in E-cadherin. BDE-99 treatment also increased the protein and mRNA levels of the transcription factor Snail, but not Slug, Twist, and ZEB1. Knockdown of Snail by siRNA significantly attenuated BDE-99-induced EMT in HCT-116 cells, suggesting that Snail plays a crucial role in BDE-99-induced EMT. The PI3K/Akt inhibitor LY294002 completely blocked BDE-99-induced Snail and invasion of HCT-116 cells.
Conclusions
Our results revealed that BDE-99 can trigger the EMT of colon cancer cells via the PI3K/AKT/Snail signaling pathway. This study provides new insight into the tumorigenesis and metastasis of CRC stimulated by BDE-99 and possibly other PBDE congeners.
ThomsenC.StigumH.FrøshaugM.BroadwellS.L.BecherG.EggesbøM.Determinants of brominated flame retardants in breast milk from a large scale Norwegian study. Environ Int.2010; 36(1): 68–74.
4.
YoguiG.T.SericanoJ.L.Polybrominated diphenyl ether flame retardants in the U.S. marine environment: a review. Environ Int.2009; 35(3): 655–666.
5.
RenX.M.GuoL.H.Molecular toxicology of polybrominated diphenyl ethers: nuclear hormone receptor mediated pathways. Environ Sci Process Impacts.2013; 15(4): 702–708.
6.
ChenD.HaleR.C.A global review of polybrominated diphenyl ether flame retardant contamination in birds. Environ Int.2010; 36(7): 800–811.
7.
ErikssonP.VibergH.JakobssonE.OrnU.FredrikssonA.A brominated flame retardant, 2,2′,4,4′,5-pentabromodiphenyl ether: uptake, retention, and induction of neurobehavioral alterations in mice during a critical phase of neonatal brain development. Toxicol Sci.2002; 67(1): 98–103.
8.
KuriyamaS.N.TalsnessC.E.GroteK.ChahoudI.Developmental exposure to low dose PBDE 99: effects on male fertility and neurobehavior in rat offspring. Environ Health Perspect.2005; 113(2): 149–154.
9.
SchreiberT.GassmannK.GötzC.Polybrominated diphenyl ethers induce developmental neurotoxicity in a human in vitro model: evidence for endocrine disruption. Environ Health Perspect.2010; 118(4): 572–578.
10.
AlbinaM.L.AlonsoV.LinaresV.Effects of exposure to BDE-99 on oxidative status of liver and kidney in adult rats. Toxicology.2010; 271(1-2): 51–56.
11.
SiegelR.NaishadhamD.JemalA.Cancer statistics, 2012. CA Cancer J Clin.2012; 62(1): 10–29.
12.
JaspersonK.W.TuohyT.M.NeklasonD.W.BurtR.W.Hereditary and familial colon cancer. Gastroenterology.2010; 138(6): 2044–2058.
13.
HurleyS.ReynoldsP.GoldbergD.NelsonD.O.JeffreyS.S.PetreasM.Adipose levels of polybrominated diphenyl ethers and risk of breast cancer. Breast Cancer Res Treat.2011; 129(2): 505–511.
14.
BarberJ.L.WalshM.J.HewittR.JonesK.C.MartinF.L.Low-dose treatment with polybrominated diphenyl ethers (PBDEs) induce altered characteristics in MCF-7 cells. Mutagenesis.2006; 21(5): 351–360.
15.
LlabjaniV.TrevisanJ.JonesK.C.ShoreR.F.MartinF.L.Derivation by infrared spectroscopy with multivariate analysis of bimodal contaminant-induced dose-response effects in MCF-7 cells. Environ Sci Technol.2011; 45(14): 6129–6135.
16.
UkpeborJ.LlabjaniV.MartinF.L.HalsallC.J.Sublethal genotoxicity and cell alterations by organophosphorus pesticides in MCF-7 cells: implications for environmentally relevant concentrations. Environ Toxicol Chem.2011; 30(3): 632–639.
17.
ValsterA.TranN.L.NakadaM.BerensM.E.ChanA.Y.SymonsM.Cell migration and invasion assays. Methods.2005; 37(2): 208–215.
18.
WangH.WangH.S.ZhouB.H.Epithelial-mesenchymal transition (EMT) induced by TNF-α requires AKT/GSK-3β-mediated stabilization of snail in colorectal cancer. PLoS ONE.2013; 8(2): e56664.
19.
JiangG.M.HeY.W.FangR.Sodium butyrate down-regulation of indoleamine 2, 3-dioxygenase at the transcriptional and post-transcriptional levels. Int J Biochem Cell Biol.2010; 42(11): 1840–1846.
20.
VoulgariA.PintzasA.Epithelial-mesenchymal transition in cancer metastasis: mechanisms, markers and strategies to overcome drug resistance in the clinic. Biochim Biophys Acta.2009; 1796(2): 75–90.
21.
PeinadoH.OlmedaD.CanoA.Snail, Zeb and bHLH factors in tumour progression: an alliance against the epithelial phenotype?Nat Rev Cancer.2007; 7(6): 415–428.
22.
GuarinoM.Epithelial-mesenchymal transition and tumour invasion. Int J Biochem Cell Biol.2007; 39(12): 2153–2160.
23.
LiZ.H.LiuX.Y.WangN.Effects of decabrominated diphenyl ether (PBDE-209) in regulation of growth and apoptosis of breast, ovarian, and cervical cancer cells. Environ Health Perspect.2012; 120(4): 541–546.
24.
BirnbaumL.S.StaskalD.F.Brominated flame retardants: cause for concern?Environ Health Perspect.2004; 112(1): 9–17.
25.
SjödinA.PattersonD.G.Jr.BergmanA.A review on human exposure to brominated flame retardants—particularly polybrominated diphenyl ethers. Environ Int.2003; 29(6): 829–839.
26.
EvandriM.G.MastrangeloS.CostaL.G.BolleP.In vitro assessment of mutagenicity and clastogenicity of BDE-99, a pentabrominated diphenyl ether flame retardant. Environ Mol Mutagen.2003; 42(2): 85–90.
27.
SlotkinT.A.CardJ.InfanteA.SeidlerF.J.BDE99 (2,2′,4,4′,5-pentabromodiphenyl ether) suppresses differentiation into neurotransmitter phenotypes in PC12 cells. Neurotoxicol Teratol.2013; 37: 13–17.
28.
SouzaA.O.PereiraL.C.OliveiraD.P.DortaD.J.BDE-99 congener induces cell death by apoptosis of human hepatoblastoma cell line - HepG2. Toxicol In Vitro.2013; 27(2): 580–587.
29.
AlmH.KultimaK.ScholzB.Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex. Neurotoxicology2008; 29(4): 628–637.
30.
ApraizI.MiJ.CristobalS.Identification of proteomic signatures of exposure to marine pollutants in mussels (Mytilus edulis). Mol Cell Proteomics.2006; 5(7): 1274–1285.
31.
SheehanK.M.GulmannC.EichlerG.S.Signal pathway profiling of epithelial and stromal compartments of colonic carcinoma reveals epithelial-mesenchymal transition. Oncogene.2008; 27(3): 323–331.
32.
Kudo-SaitoC.ShirakoH.TakeuchiT.KawakamiY.Cancer metastasis is accelerated through immunosuppression during Snail-induced EMT of cancer cells. Cancer Cell.2009; 15(3): 195–206.
33.
FanX.J.WanX.B.YangZ.L.Snail promotes lymph node metastasis and Twist enhances tumor deposit formation through epithelial-mesenchymal transition in colorectal cancer. Hum Pathol.2013; 44(2): 173–180.
34.
SavagnerP.The epithelial-mesenchymal transition (EMT) phenomenon. Ann Oncol.2010; 21(Suppl 7): vii89–vii92.
