TY - JOUR AU - Kaschek, Lea AU - Vialle, Joanne AU - Stopper, Gebhard AU - Hoffmann, Markus D A AU - Zöphel, Sylvia AU - Jansky, Johanna AU - Küchler, Nadja AU - Schäfer, Gertrud AU - Moter, Alina AU - Wendel, Philipp AU - Neumann, Frank AU - Schormann, Claudia AU - Ullrich, Evelyn AU - Roma, Leticia Prates AU - Kummerow, Carsten AU - Thurner, Lorenz AU - Schwarz, Eva C AU - Hoth, Markus TI - Fura-10, unlike fura-2, is suitable for long-term calcium imaging in natural killer (NK) cells without compromising cytotoxicity and can be combined with target cell death analysis. JO - Cell calcium VL - 133 SN - 0143-4160 CY - Edinburgh [u.a.] PB - Churchill Livingstone M1 - DKFZ-2025-02655 SP - 103091 PY - 2025 AB - There are compelling reasons to opt for primary human natural killer (NK) cells when validating Ca2+ indicators. 1.) NK cells exhibit a high degree of vulnerability to stressors such as indicator loading or light exposure. 2.) The lack of research on NK Ca2+ signaling underscores the necessity for developing reliable assays. 3.) The increased utilization of NK cell therapies necessitates a more profound comprehension of Ca2+ dependent signal transduction. Consequently, an assay was developed to monitor cytosolic Ca2+ signals in individual NK cells simultaneously with their cytotoxic function against cancer cells. We used this assay to assess the suitability of fura-2, fura-PE3, fura-8, fura-10 or fura-red for quantifying Ca2+ signals in NK cells without compromising their cytotoxic function. In contrast to the widely used fura-2, its red-shifted derivative fura-10 did not interfere with NK cytotoxicity over several hours. It exhibited a superior signal-to-noise ratio and good dynamic range, accompanied by minimal bleaching or leakage. Fura-8 and fura-red also preserved NK cell cytotoxicity, but had other disadvantages compared to fura-10. We successfully used fura-10 to report Ca2+ signals in NK cells from blood donors and patients diagnosed with lymphoma and leukemia over several hours at 37 °C during apoptotic or necrotic killing of different cancer cells (K562, THP1, OCI-AML2, and TMD8). Additionally, we show that fura-10 is well suited to report Ca2+ signals in intact murine pancreatic islets, another stress-sensitive cell preparation. Consequently, fura-10 is an optimal choice for measuring Ca²⁺ in primary human NK cells and other primary cell preparations. KW - Calcium (Other) KW - Cytotoxicity (Other) KW - Fura-10 (Other) KW - Fura-2 (Other) KW - Natural killer (NK) cell (Other) KW - Pancreatic islets (Other) KW - cancer (Other) LB - PUB:(DE-HGF)16 C6 - pmid:41314008 DO - DOI:10.1016/j.ceca.2025.103091 UR - https://inrepo02.dkfz.de/record/306662 ER -