title: Silver nanoparticles exert a long-lasting antiproliferative effect on human keratinocyte HaCaT cell line.
abstract: For their antibacterial activity, silver nanoparticles (Ag NPs) are largely used in various commercially available products designed to come in direct contact with the skin. In this study we investigated the effects of Ag NPs on skin using the human-derived keratinocyte HaCaT cell line model. Ag NPs caused a concentration- and time-dependent decrease of cell viability, with IC(50) values of 6.8 ± 1.3 μM (MTT assay) and 12 ± 1.2 μM (SRB assay) after 7 days of contact. A 24h treatment, followed by a 6 day recovery period in Ag NPs-free medium, reduced cell viability with almost the same potency (IC(50)s of 15.3 ± 4.6 and 35 ± 20 μM, MTT and SRB assays, respectively). Under these conditions, no evidence of induction of necrotic events (propidium iodide assay) was found. Apocynin, NADPH-oxidase inhibitor, or N(G)-monomethyl-L-argynine, nitric oxide synthase inhibitor, did not prevent NPs-induced reduction of cell viability. TEM analysis of cells exposed to NPs for 24h revealed alteration of nuclear morphology but only a marginal presence of individual NPs inside the cells. These results demonstrate that on HaCaT keratinocytes a relatively short time of contact with Ag NPs causes a long-lasting inhibition of cell growth, not associated with consistent Ag NPs internalization.
authors.affiliation: Department of Life Sciences, University of Trieste, Via L. Giorgeri 7/9, 34127 Trieste, Italy. czanette@units.it
authors.forename: Caterina
authors.initials: C
authors.lastname: Zanette
authors.forename: Marco
authors.initials: M
authors.lastname: Pelin
authors.forename: Matteo
authors.initials: M
authors.lastname: Crosera
authors.forename: Gianpiero
authors.initials: G
authors.lastname: Adami
authors.forename: Massimo
authors.initials: M
authors.lastname: Bovenzi
authors.forename: Francesca Filon
authors.initials: FF
authors.lastname: Larese
authors.forename: Chiara
authors.initials: C
authors.lastname: Florio
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D046529:Microscopy, Electron, Transmission; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D009336:Necrosis / Q000473:pathology; D017382:Reactive Oxygen Species; D012834:Silver / Q000737:chemistry / Q000633:toxicity*
chemical_list: D000098:Acetophenones; D017382:Reactive Oxygen Species; D012834:Silver; C056165:acetovanillone; D019255:NADPH Oxidases