Fig. 4: Time-lapse microscopy reveals either an apoptotic non-mitotic cell death or death in mitosis.

Using live cell imaging, HNSCC cell lines were followed for 24 h per condition. Each horizontal bar represents a single cell that was tracked over time (in minutes) at the x-axis. Pre-mitosis (gray bars) represents the time a cell spent in G1/G0-, S- and G2-phase before mitosis (yellow bars). Post-mitosis (blue bars) is the time a cell spent in G1/G0-, S- and G2-phase after mitosis combined. Bars are ranked to length of the pre-mitotic phase. a Mitotic cell death (red bars) was observed in 3 of 50 cells of the sensitive cell line UM-SCC-22A without treatment. However, with LY2603618/Rabusertib treatment, only 6 of 50 cells died by death in mitosis (red bars), whereas 33 of 50 cells underwent non-mitotic cell death characterized by blebbing (green bars). b Of the less-sensitive cell line VU-SCC-096, mitotic cell death (red bars) occurred in 3 of 50 cells when left untreated. Treatment with LY2603618/Rabusertib caused death in mitosis in 27 of 50 cells (red bars) and in 10 of 50 non-mitotic cell death (green bars). c Representable example of observed cell death mechanisms with live-cell imaging. UM-SCC-22A cells undergo non-mitotic cell death by displaying apoptotic-bodies (blebbing). Within similar timespan, VU-SCC-096 cells enter mitosis that lasted for ~12 h, followed by mitotic cell death