In vitro comet and micronucleus assays do not predict morphological transforming effects of silica particles in Syrian Hamster Embryo cells

Darné, Christian; Coulais, Catherine; Terzetti, F.; Fontana, C. M.; Binet, Stéphane; Gaté, Laurent; Guichard, Yves

doi:10.1016/j.mrgentox.2015.11.012

Cited by 10 publications

(14 citation statements)

References 42 publications

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“…However, macrophages are not considered relevant as surrogate target cells to evaluate genotoxic damage to the lung [ 6 ]. In addition, MN and comet results do not correlate with particle induced carcinogenicity as demonstrated by Darne et al [ 24 ]. They studied MN and comet induction in Syrian hamster embryo (SHE) cells, and in Chinese hamster lung (V79) cells, to evaluate the genotoxicity of quartz (Min-U-Sil, fully crystallised), commercial cristobalite (Chd, partly crystallised) and chrysotile (asbestos) as known carcinogens, and diatomaceous earth (DE, 100% amorphous) as control.…”

Section: Methodsmentioning

confidence: 89%

An updated review of the genotoxicity of respirable crystalline silica

Borm¹,

Fowler²,

Kirkland³

2018

Part Fibre Toxicol

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Human exposure to (certain forms of) crystalline silica (CS) potentially results in adverse effects on human health. Since 1997 IARC has classified CS as a Group 1 carcinogen [1], which was confirmed in a later review in 2012 [2]. The genotoxic potential and mode of genotoxic action of CS was not conclusive in either of the IARC reviews, although a proposal for mode of actions was made in an extensive review of the genotoxicity of CS by Borm, Tran and Donaldson in 2011 [3]. The present study identified 141 new papers from search strings related to genotoxicity of respirable CS (RCS) since 2011 and, of these, 17 relevant publications with genotoxicity data were included in this detailed review.Studies on in vitro genotoxic endpoints primarily included micronucleus (MN) frequency and % fragmented DNA as measured in the comet assay, and were mostly negative, apart from two studies using primary or cultured macrophages. In vivo studies confirmed the role of persistent inflammation due to quartz surface toxicity leading to anti-oxidant responses in mice and rats, but DNA damage was only seen in rats. The role of surface characteristics was strengthened by in vitro and in vivo studies using aluminium or hydrophobic treatment to quench the silanol groups on the CS surface.In conclusion, the different modes of action of RCS-induced genotoxicity have been evaluated in a series of independent, adequate studies since 2011. Earlier conclusions on the role of inflammation driven by quartz surface in genotoxic and carcinogenic effects after inhalation are confirmed and findings support a practical threshold. Whereas classic in vitro genotoxicity studies confirm an earlier no-observed effect level (NOEL) in cell cultures of 60-70 μg/cm2, transformation frequency in SHE cells suggests a lower threshold around 5 μg/cm2. Both levels are only achieved in vivo at doses (2–4 mg) beyond in vivo doses (> 200 μg) that cause persistent inflammation and tissue remodelling in the rat lung.

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Section: Methodsmentioning

confidence: 89%

An updated review of the genotoxicity of respirable crystalline silica

Borm¹,

Fowler²,

Kirkland³

2018

Part Fibre Toxicol

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“…Accordingly, we investigated the effect of a nano-silica particle, NM-203, on Bhas 42 cells. In parallel, we also tested a crystalline silica microparticle, Min-U-Sil® 5, known for its transforming and carcinogenic properties (Darne et al, 2016). In a previous work, we observed that both particles induced Bhas 42 cell transformation in the promotion assay (Fontana et al, In press).…”

Section: Discussionmentioning

confidence: 98%

“…In addition, silica particles can induce oxidative stress leading to DNA damage and are responsible for gene silencing through DNA methylation of genes involved in cell cycle regulation (Belinsky et al, 2002, Deshpande et al, 2002, Knaapen et al, 2002. While treatment by the crystalline silica microparticle Min-U-Sil® 5 induced in vitro neoplastic transformation, treatment by amorphous silica nanoparticles did not induce BALB/3T3 or SHE cell transformation (Darne et al, 2016, Saffiotti and Ahmed, 1995, Uboldi et al, 2012. However, recent studies described that synthetic amorphous silica nanoparticles induce in in vitro models oxidative stress and genotoxic effects or in in vivo models cellular cell death and fibrosis , Murugadoss et al, 2017.…”

Section: Introductionmentioning

confidence: 99%

Epigenetic changes in the early stage of silica-induced cell transformation

et al. 2017

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The increasing use of nanomaterials in numerous domains has led to growing concern about their potential toxicological properties, and the potential risk to human health posed by silica nanoparticles remains under debate. Recent studies proposed that these particles could alter gene expression through the modulation of epigenetic marks, and the possible relationship between particle exposure and these mechanisms could represent a critical factor in carcinogenicity. In this study, using the Bhas 42 cell model, we compare the effects of exposure to two transforming particles, a pyrogenic amorphous silica nanoparticle NM-203 to those of the crystalline silica particle Min-U-Sil 5. Short-term treatment by Min-U-Sil 5 decreased global DNA methylation and increased the expression of the two de novo DNMTs, DNMT3a and DNMT3b. NM-203 treatment affected neither the expression of these enzymes nor DNA methylation. Moreover, modified global histone H4 acetylation status and HDAC protein levels were observed only in the Min-U-Sil 5-treated cells. Finally, both types of particle treatment induced strong c-Myc expression in the early stage of cell transformation and this correlated with enrichment in RNA polymerase II as well as histone active marks on its promoter. Lastly, almost all parameters that were modulated in the early stage were restored in transformed cells suggesting their involvement mainly in the first steps of cell transformation.

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“…In the present study, the suitability of the Bhas 42 CTA for particle-type substances was assessed using crystalline (quartz Min-U-Sil 5) and amorphous (diatomaceous earth) silica microparticles that have been previously evaluated for their transforming activity in the Syrian hamster embryonic (SHE) CTA [17,18]. [19] (Table 1).…”

Section: Introductionmentioning

confidence: 99%

In vitro cell transformation induced by synthetic amorphous silica nanoparticles

Fontana

Kirsch

Seidel

et al. 2017

Mutation Research/Genetic Toxicology and Environmental Mutagene

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International audienceSynthetic amorphous silica nanoparticles (SAS) are among the most widely produced and used nanomaterials, but little is known about their carcinogenic potential. This study aims to evaluate the ability of four different SAS, two precipitated, NM-200 and NM-201, and two pyrogenic, NM-202 and NM-203, to induce the transformation process. For this, we used the recently developed in vitro Bhas 42 cell transformation assay (CTA). The genome of the transgenic Bhas 42 cells contains several copies of the v-Ha-ras gene, making them particularly sensitive to tumor-promoter agents. The Bhas 42 CTA, which includes an initiation assay and a promotion assay, was validated in our laboratory using known soluble carcinogenic substances. Its suitability for particle-type substances was verified by using quartz Min-U-Sil 5 (Min-U-Sil) and diatomaceous earth (DE) microparticles. As expected given their known transforming properties, Min-U-Sil responded positively in the Bhas 42 CTA and DE responded negatively. Transformation assays were performed with SAS at concentrations ranging from 2 µg/cm 2 to 80 µg/cm 2. Results showed that all SAS have the capacity to induce transformed foci, interestingly only in the promotion assay, suggesting a mode of action similar to tumor-promoter substances. NM-203 exhibited transforming activity at a lower concentration than the other SAS. In conclusion, this study showed for the first time the transforming potential of different SAS, which act as tumor-promoter substances in the Bhas 42 model of cell transformation.Les nanoparticules de silice amorphes de synthèse (SAS) sont les nanomatériaux les plus produits et les plus utilisés dans le monde, mais leur potentiel cancérogène est peu étudié. Cette étude avait pour but d’évaluer la capacité de quatre différentes SAS, deux sous forme précipitée, NM-200 et NM-201 et deux sous forme pyrogénée, NM-202 et NM-203, d’induire des processus de cancérogénèse. Pour cela, nous avons utilisé l’essai de transformation sur les cellules Bhas 42 (Bhas 42 CTA) qui a été récemment développé. Le génome des cellules Bhas 42 transgéniques contient plusieurs copies du gène v-Ha-ras, ce qui leur confère les caractéristiques de cellules « initiées » et les rend particulièrement sensibles aux agents promoteurs de tumeur. Le Bhas 42 CTA, qui inclut un essai d’initiation et un essai de promotion, a été validé dans notre laboratoire en utilisant des agents cancérogènes solubles connus. Son adaptabilité pour des substances de type particule a été vérifié en utilisant des microparticules de quartz Min-U-Sil 5 (Min-U-Sil) et de terre de diatomée (DE). Comme attendu d’après leur propriété transformante connue, le Min-U-Sil a répondu positivement et la DE négativement au Bhas 42 CTA. Les essais de transformation ont été réalisés à des concentrations de SAS s’étalant de 2 µg/cm2 à 80 µg/cm2. Les résultats montrent que toutes les SAS ont la capacité d’induire des foyers de transformation et de manière intéressante, uniquement dans l’essai de promotion, suggérant...

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In vitro comet and micronucleus assays do not predict morphological transforming effects of silica particles in Syrian Hamster Embryo cells

Cited by 10 publications

References 42 publications

An updated review of the genotoxicity of respirable crystalline silica

An updated review of the genotoxicity of respirable crystalline silica

Epigenetic changes in the early stage of silica-induced cell transformation

In vitro cell transformation induced by synthetic amorphous silica nanoparticles

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