Suitability of human and mammalian cells of different origin for the assessment of genotoxicity of metal and polymeric engineered nanoparticles

Abstract

Nanogenotoxicity is a crucial endpoint in safety testing of nanomaterials as it addresses potential mutagenicity, which has implications for risks of both genetic disease and carcinogenesis. Within the NanoTEST project, we investigated the genotoxic potential of well-characterised nanoparticles (NPs): titanium dioxide (TiO2) NPs of nominal size 20 nm, iron oxide (8 nm) both uncoated (U-Fe3O4) and oleic acid coated (OC-Fe3O4), rhodamine-labelled amorphous silica 25 (Fl-25 SiO2) and 50 nm (Fl-50 SiO) and polylactic glycolic acid polyethylene oxide polymeric NPs - as well as Endorem® as a negative control for detection of strand breaks and oxidised DNA lesions with the alkaline comet assay. Using primary cells and cell lines derived from blood (human lymphocytes and lymphoblastoid TK6 cells), vascular/central nervous system (human endothelial human cerebral endothelial cells), liver (rat hepatocytes and Kupffer cells), kidney (monkey Cos-1 and human HEK293 cells), lung (human bronchial 16HBE14o cells) and placenta (human BeWo b30), we were interested in which in vitro cell model is sufficient to detect positive (genotoxic) and negative (non-genotoxic) responses. All in vitro studies were harmonized, i.e. NPs from the same batch, and identical dispersion protocols (for TiO2 NPs, two dispersions were used), exposure time, concentration range, culture conditions and time-courses were used. The results from the statistical evaluation show that OC-Fe3O4 and TiO2 NPs are genotoxic in the experimental conditions used. When all NPs were included in the analysis, no differences were seen among cell lines - demonstrating the usefulness of the assay in all cells to identify genotoxic and non-genotoxic NPs. The TK6 cells, human lymphocytes, BeWo b30 and kidney cells seem to be the most reliable for detecting a dose-response.

Immunotoxicity, genotoxicity and epigenetic toxicity of nanomaterials: New strategies for toxicity testing?

“…DNA damage can be measured with various assays such as alkaline elution, neutral elution, DNA unwinding chromatography (Semisch et al, 2014), fluorometric detection of alkaline DNA unwinding (Moreno-Villanueva et al, 2011), or g-H2AX double strand break assay, but the most common test for detecting DNA damage after NM exposure is the comet assay (Magdolenova et al, 2014;Cowie et al, 2015;El Yamani et al, 2017).…”

“…The in vitro methods were critically evaluated, and where appropriate, standard methods were adapted . The suitability of human and mammalian primary cells and cell lines derived from blood, vascular/central nervous system, liver, kidney, lung and placenta for the assessment of NM genotoxicity (DNA strand breaks and oxidized DNA lesions) was investigated by Cowie et al, (2015). The results from the statistical evaluation showed that all of the cell types can be used to assess the genotoxic potential of NMs, but with different sensitivities.…”

High throughput toxicity screening and intracellular detection of nanomaterials

“…Recently, several suitable candidate control NMs have been described. Iron oxide was suggested as a positive control for cytotoxicity, oxidative stress and genotoxicity endpoints and PLGA‐PEO as a negative control 123, 133. Also aminated polystyrene nanobeads were suggested as a positive control for acute toxicity,99, 110 including cytotoxicity and membrane damage187 but also activation of the inflamasome pathway,188, 189 while carboxylated nanodiamonds (as negative control) were found to be neither cytotoxic nor genotoxic on several human cell lines 99.…”

Lessons learned from research on air pollution and other particles in the toxicology of nanomaterials and vice versa

“…The in vitro methods were critically evaluated, and where appropriate, standard methods were adapted [Dusinska et al, ]. The suitability of human and mammalian primary cells and cell lines derived from blood, vascular/central nervous system, liver, kidney, lung, and placenta for the assessment of NM genotoxicity (DNA strand breaks and oxidized DNA lesions) was investigated by Cowie et al []. The results from the statistical evaluation showed that all of the cell types can be used to assess the genotoxic potential of NMs, but with different sensitivities.…”