For detection and/or quantification of cell death, forward/sideward light scattering analysis and AnnexinV/propidium iodide-staining were used as described (Bernhard et al., 2003). AnnexinV/PI− staining allows the discrimination of intact viable cells (AnnexinV− negative and PI− negative), early apoptotic (AnnexinV− positive and

PI− negative) and necrotic cells (AnnexinV− positive and PI− positive). The number of viable cells was determined using the XTT assay (Biomol GmbH, Hamburg, Germany). HUVECs were seeded into gelatine coated 96-well plates. After 24 h the medium was replaced by fresh medium and the cells were treated with various Cd concentrations ATM/ATR inhibitor review for the indicated times. For further details see manufacturers’ instructions. The amount of BTK inhibitor lactate dehydrogenase (LDH) released from cells was quantified using the LDH cytotoxicity kit II (Biovision) according to the manufacturer’s instructions. For the detection and quantification of nuclear DNA content, HUVECs were seeded into gelatine coated 6-well plates and allowed to adhere over night. After replacing the medium with fresh medium, the cells were incubated with various Cd concentrations for the indicated times. After enzymatic detachment, the cells were permeabilized with saponin (1 mg/ml), stained with propidium iodide (50 μg/ml) and analysed and quantified

by flowcytometry using a Cytomics FC 500 (Beckmann Coulter, Brea, CA, USA). To analyse the subcellular localization of DNAse II, HUVECs were treated with Cd for the indicated times. After treatment, the cells were washed with PBS and fixed with 4% PFA for

3 min at room temperature. Fixed cells were washed with PBS and permeabilized with 0.3% Triton X-100 for 30 min. Following an additional washing step with PBS, non-specific binding sites were blocked with 1% bovine serum albumin (BSA) in PBS for 30 min at room temperature followed by staining with primary antibody against DNAse II (mouse polyclonal antibody, Abnova GmbH, Heidelberg, Germany; 10 μg/ml) for 1 h at room temperature. After 3 washing steps with PBS, the cells were incubated with secondary antibody (Alexa Fluor 488, Bay 11-7085 goat anti-mouse, Invitrogen, Carlsbad, CA, USA) for 1 h in the dark and at room temperature. Thereafter, the monolayer was washed 3 times with PBS and nuclear staining was performed using propidium iodide (1 μg/ml) for 8 min at room temperature in the dark. After 3 final washing steps, cells were mounted in ProLong Gold (Invitrogen, Carlsbad, CA, USA) and analysed using a LSM 510 Meta attached to an Axioplan 2 imaging MOT using ZEN software (Zeiss, Oberkochen, Germany). To analyse cytosolic nuclease activity of Cd treated HUVECs, nuclear DNA was extracted from endothelial cells using a DNA purification kit (Promega GmbH, USA). Nuclear DNA (2 μg) was then incubated with cytosolic extracts of Cd-treated HUVECs and controls (30 μg) for 3 h at 37 °C. DNA fragmentation was analysed by agarose gel electrophoresis (0.5%).