Phosphate buffered saline solution

Doxorubicin hydrochloride (≥ 98% purity, DOX), Ponceau S, direct red 80, 5,5-dithiobis(2-nitrobenzoic acid), adenosine triphosphate (ATP), reduced glutathione (GSH), glutathione reductase, oxidized glutathione (GSSG) disodium salt, bovine serum albumin, and the all other chemicals used were purchased from Sigma-Aldrich (St. Louis, MO, USA). Phosphate-buffered saline solution was purchased from Biochrom (Berlin, Germany), and sodium chloride (NaCl) was acquired from VWR (Leuven, Belgium). Isoflurane (Isoflo^®) was obtained from Abbott Animal Health (North Chicago, IL, USA). Harris haematoxylin was purchased from Harris Surgipath (Richmond, IL, USA), and 1% aqueous eosin from Australian Biostain (Traralgon, Australia). The Bio-Rad DC protein assay kit was obtained from Bio-Rad Laboratories (Hercules, CA, USA). Primary antibodies were acquired from different sources which are indicated in Supplementary Table S1. Goat anti-rabbit IgG-horseradish peroxidase (ab97051) and goat anti-mouse IgG-horseradish peroxidase (ab6728) were provided by Abcam (Cambridge, UK), while enhanced chemiluminescence (Clarity Western ECL, 1.705.060) reagents and the Bio-Rad DC protein assay kit were purchased from Bio-Rad Laboratories (Hercules, CA, USA). Amersham Protran nitrocellulose blotting membranes (0.45 µm) were supplied by Cytiva (Buckinghamshire, UK).

The cell vitality was determined using an MTT assay (Mosmann 1983 (link)) as described in Sachs et al. (2017 ). This approach measures the activity of mitochondrial and cytosolic dehydrogenases, which reduces the yellow, water soluble 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) to a blue, water-insoluble formazan product (Lindl and Gstraunthaler 2008 ).
After cell exposure to Eu(III) or U(VI), 50 mg of fresh cells were weighed into 1.5-mL reaction tubes (Greiner) followed by the addition of 1-mL phosphate-buffered saline solution without Ca²⁺ and Mg²⁺ (PBS; Biochrom, Berlin, Germany) and 200 μL MTT solution (5 mg/mL; Duchefa, Harlem, The Netherlands). Subsequently, the assay was performed as described in Sachs et al. (2017 ). The vitality of the Eu(III) and U(VI) exposed cells was determined as a percentage of the control samples according to Eq. (1). $$\text{Cell vitality}\left(\%\text{of control}\right)=\frac{\text{Absorbance of exposed cells}}{\text{Absorbance of control cells}}\times 100$$
The results represent data from five independent experiments, each with two to three samples for control and each metal concentration.

Doxorubicin hydrochloride (≥ 98% purity, DOX), Ponceau S, direct red 80, bovine serum albumin, and the all other chemicals used were obtained from Sigma-Aldrich (St. Louis, MO, USA). Phosphate buffered saline solution was purchased from Biochrom (Berlin, Germany), and sodium chloride (NaCl) was acquired from VWR (Leuven, Belgium). Isoflurane (Isoflo^®) was acquired from Abbott Animal Health (North Chicago, IL, USA). Harris haematoxylin was purchased from Harris Surgipath (Richmond, IL, USA), and 1% aqueous eosin from Australian Biostain (Traralgon, Australia). The Bio-Rad DC protein assay kit was obtained from Bio-Rad Laboratories (Hercules, CA, USA). Primary and secondary antibodies used in Western blot and immunohistochemistry are shown in Supplementary Table S1. Enhanced chemiluminescence (Clarity Western ECL, ref. 1705060) reagents and the Bio-Rad DC protein assay kit were bought from Bio-Rad Laboratories (Hercules, CA, USA). Amersham Protran nitrocellulose blotting membranes (0.45 µm) were supplied by Cytiva (Buckinghamshire, UK).