Cell viability was assayed using either the CellTiter AQueous Non-Radioactive Cell Proliferation Assay (MTS, Huntsville, AL, USA) or CellTiter Luminescent Cell Viability Assay (Promega, Madison, WI, USA) as described previously.18 (link) BrdU incorporation was assayed using a BrdU Cell Proliferation Assay according to the manufacturer's suggested protocol (Calbiochem, Billerica, MA, USA). Real time analysis of cellular proliferation by xCELLligence assay was performed as described previously.18 (link)Apoptosis was determined by nuclear fragmentation assay as described previously.54 (link), 55 (link), 56 (link), 57 (link) Quantifications were performed in triplicate, with each count consisting of at least 300 cells. Caspase 3/7 activation was evaluated by Caspase 3/7 kit (Promega) according to the manufacturer's suggested protocol.