title: Evaluation of tumorigenic potential of CeO2and Fe2O3engineered nanoparticles by a human cellin vitroscreening model.
abstract: With rapid development of novel nanotechnologies that incorporate engineered nanomaterials (ENMs) into manufactured products, long-term, low dose ENM exposures in occupational settings is forecasted to occur with potential adverse outcomes to human health. Few ENM human health risk assessment efforts have evaluated tumorigenic potential of ENMs. Two widely used nano-scaled metal oxides (NMOs), cerium oxide (nCeO2) and ferric oxide (nFe2O3) were screened in the current study using a sub-chronic exposure to human primary small airway epithelial cells (pSAECs). Multi-walled carbon nanotubes (MWCNT), a known ENM tumor promoter, was used as a positive control. Advanced dosimetry modeling was employed to ascertain deliveredvs.administered dose in all experimental conditions. Cells were continuously exposedin vitroto deposited doses of 0.18 μg/cm2or 0.06 μg/cm2of each NMO or MWCNT, respectively, over 6 and 10 weeks, while saline- and dispersant-only exposed cells served as passage controls. Cells were evaluated for changes in several cancer hallmarks, as evidence for neoplastic transformation. At 10 weeks, nFe2O3- and MWCNT-exposed cells displayed a neoplastic-like transformation phenotype with significant increased proliferation, invasion and soft agar colony formation ability compared to controls. nCeO2-exposed cells showed increased proliferative capacity only. Isolated nFe2O3and MWCNT clones from soft agar colonies retained their respective neoplastic-like phenotypes. Interestingly, nFe2O3-exposed cells, but not MWCNT cells, exhibited immortalization and retention of the neoplastic phenotype after repeated passaging (12 - 30 passages) and after cryofreeze and thawing. High content screening and protein expression analyses in acute exposure ENM studiesvs.immortalized nFe2O3cells, and isolated ENM clones, suggested that long-term exposure to the tested ENMs resulted in iron homeostasis disruption, an increased labile ferrous iron pool, and subsequent reactive oxygen species generation, a well-established tumorigenesis promotor. In conclusion, sub-chronic exposure to human pSAECs with a cancer hallmark screening battery identified nFe2O3as possessing neoplastic-like transformation ability, thus suggesting that further tumorigenic assessment is needed.
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505; Department of Pharmaceutical Sciences, West Virginia University, Morgantown WV, 26506.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Stueckle
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505.
authors.forename: Donna C
authors.initials: DC
authors.lastname: Davidson
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505.
authors.forename: Raymond
authors.initials: R
authors.lastname: Derk
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505; Department of Pharmaceutical Sciences, West Virginia University, Morgantown WV, 26506.
authors.forename: Tiffany G
authors.initials: TG
authors.lastname: Kornberg
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505.
authors.forename: Diane
authors.initials: D
authors.lastname: Schwegler-Berry
authors.affiliation: Center for Nanotechnology and Nanotoxicology, Harvard T. H. Chan School of Public Health, Boston MA.
authors.forename: Sandra V
authors.initials: SV
authors.lastname: Pirela
authors.affiliation: Center for Nanotechnology and Nanotoxicology, Harvard T. H. Chan School of Public Health, Boston MA.
authors.forename: Glen
authors.initials: G
authors.lastname: Deloid
authors.affiliation: Center for Nanotechnology and Nanotoxicology, Harvard T. H. Chan School of Public Health, Boston MA.
authors.forename: Philip
authors.initials: P
authors.lastname: Demokritou
authors.affiliation: Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Sudjit
authors.initials: S
authors.lastname: Luanpitpong
authors.affiliation: Department of Pharmaceutical Sciences, West Virginia University, Morgantown WV, 26506.
authors.forename: Yon
authors.initials: Y
authors.lastname: Rojanasakul
authors.affiliation: HELD, National Institute for Occupational Safety and Health, Morgantown WV, 26505.
authors.forename: Liying
authors.initials: L
authors.lastname: Wang
keywords: iron homeostasis; nano-scaled metal oxide; nanomaterial; neoplastic transformation; tumorigenesis