Table 2.
Description of the in vitro reporter gene bioassays used to assess biological activities in passive samples from the Joint Danube Survey 4 (JDS4).
| Endpoint (mode of action) | Bioassay/cell line | Bioanalytical laboratory | Reference compound | EC10 or ECIR1.5 or IC20 of reference compound ± SEM (M)a | BEQ | Bioassay method reference | Type of cytotoxicity testing | EBT | Reference for EBT |
|---|---|---|---|---|---|---|---|---|---|
| Xenobiotic metabolism | |||||||||
| transactivation of aryl hydrocarbon receptor | CAFLUX /H4G1.1c2 | RECETOX | 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) | 2.5 × 10-12 ± 4.0 × 10-14 |
TCDD-EQ | Nagy et al., 2002 | neutral red assay | 106 pg/L TCDD EQs | Read-across from the EBT from Escher and Neale 2021 for the AhR CALUX (H4L7.5c2 (Brennan et al.) and translated into TCDD b |
| transactivation of peroxisome proliferator-activated receptor, isoform gamma | PPARγ GeneBLAzer/ HEK293H | UFZ | Rosiglitazone | 4.2 × 10-10 ± 3.9 × 10-11 |
Rosiglitazone-EQ | Invitrogen 2007a | cell confluence | 1.2 μg/L Rosiglitazone EQs | Escher and Neale, 2021 |
| Reactive mode of action | |||||||||
| adaptive response to oxidative stress | AREc32/ MCF-7 | UFZ | Benzo(a)pyrene (B(a)P) | 1.65 × 10-7c | B(a)P-EQ | Escher et al., 2021 | cell confluence | 34 μg/L B(a)P EQd | Escher and Neale, 2021 |
| Specific mode of action | |||||||||
| transactivation of estrogen receptor, isoform alpha | ERα GeneBLAzer/ HEK293T | UFZ | 17ß-estradiol (E2) | 1.7 × 10-11 ± 4.0 × 10-13 |
EEQ | Invitrogen 2007b | cell confluence | 0.34 ng/L EEQ | Escher et al., 2018 |
| transactivation of androgen receptor | AR agonism /MDA-kb2 | RECETOX | Dihydrotestosterone (DHT) | 2.3 × 10-11 ± 1.7 × 10-12 |
DHT-EQ | Wilson et al., 2002 | neutral red assay | NA | NA |
| androgen receptor antagonism | AR antagonism /MDA-kb2 | RECETOX | Flutamide (FLU) | 2.2 × 10-7 ± 2.2 × 10-8 |
FLU-EQ | Wilson et al., 2002 | neutral red assay | 3.5 μg/L FLU EQs | Escher et al., 2018 |
| transactivation of glucocorticoid receptor | GR GeneBLAzer/ HEK293T | UFZ | Dexamethasone (DEX) | 6.5 × 10-10 ± 2.7 × 10-11 |
DEX-EQ | Invitrogen 2007c | cell confluence | NA | NA |
Abbreviations and description:a - ECIR1.5 was calculated for the reference compound benzo(a)pyrene, IC20 was derived for flutamide, EC20 was derived for TCDD, otherwise we expressed the effective concentrations as EC10, b - calculated from EBT given in Escher and Neale (2021) by conversion of 250 ng/L B(a)P-EQ to 106 pg/L TCDD-EQ (EC10 TCDD = 0.41 ng/L and EC10 of B(a)P = 961 ng/L) based on their relative potencies, c - ECIR1.5 of B(a)P taken from Lee et al. (2021), d – calculated from EBT-dichlorvos-EQ of 1.4 mgdichlorvos/L from Escher and Neale (2021) by conversion to an EBT-B(a)P-EQ of 34 μgB(a)P/L (ECIR1.5 dichlorvos = 1.7 mg/L and ECIR1.5B(a)P = 41.6 μg/L). BEQ - Bioanalytical equivalence concentration, NA – not available. RECETOX – Faculty of Science at Masaryk University (Brno, the Czech Republic), SEM – standard error of the mean, UFZ – Helmholtz Centre for Environmental Research (Leipzig, Germany).