Ud scc2

All cell lines were purchased from ATCC (Manassas Va) except: UM-SCC47 obtained from Dr Carey at the University of Michigan, SCC-90, PCI-30 and PCI-15B from Dr Robert Ferris at the University of Pittsburgh, SKOV3-luc from Dr Dmitry Pankov at MSK, 93-VU-147T and HeLa from Dr Luc Morris and UD-SCC2 from Henning Bier at Hals-Nasen-Ohrenklinik und Poliklinik. All cells were authenticated by short tandem repeat profiling using PowerPlex 1.2 System (Promega), and periodically tested for mycoplasma using a commercial kit (Lonza). The luciferase-labeled tumor cell lines MCF7-Luc were generated by retroviral infection with a SFG-GFLuc vector.

HNSCC cell lines Cal 27, Cal 33, UDSCC 2, UPCISCC 040, UPCISCC 099, UPCISCC 131, UPCISCC 154 were purchased from ATCC (Manassas, VA, USA), DSMZ (Braunschweig, Germany), or obtained from Prof. Thomas Hoffmann (University of Ulm, Germany) and authenticated after retrieval by short tandem repeat (STR) typing (service by DSMZ) [45 (link)–47 (link)]. Cell lines were cultured in DMEM supplemented with 10% FCS, 100 U/ml penicillin, and 100 µg/ml streptomycin (all from Thermo Scientific, Schwerte, Germany) at 37 °C and 7.5% CO₂. Human hTERT-immortalized keratinocytes OKF 6 were cultured in a 2 + 1 + 1 Keratinocyte-SFM/DMEM/F12 nutrient mixture, supplemented with 0.3 ng/ml rEGF, 35 µg/ml bovine pituitary extract, 155 µM CaCl₂, 1.5 mM Glutamax, 25 U/ml penicillin, and 25 µg/ml streptomycin (Thermo Scientific) [48 (link)]. All cell lines were routinely tested negative for mycoplasma contamination. Cells were irradiated at the indicated doses using an RS225 X-ray cabinet (X-Strahl, Camberley, UK) operated at 200 kV/10 mA (Thoraeus filter, 1 Gy in 63 s).