Fig. 2

Formation of ovarian cancer PGCCs by cell fusion. a Ovarian cancer cells (COV318 and SKOV3) double-positive for green and far-red cytoplasmic dyes were sorted by flow cytometry following the induction of cell fusion with 300 μM CoCl₂ for 48 h. Scale bars represent 100 μm. b SKOV3 cells were transfected with plasmids encoding for red (SKOV3-Red) and green (SKOV3-Green) nuclear fluorescent proteins and mixed in co-culture. Under regular culture conditions, cells spontaneously formed PGCCs by cell fusion, visualized by polynucleated cells with both red and green nuclei (circled in yellow). Scale bars represent 200 μm (with two high magnifications of selected portions at the bottom). c and d Co-culture of SKOV3-Green and SKOV3-Red cells was treated with 1 μM HA15 for 48 h. c The cells were labeled with Phalloidin (actin, pink/grey). The presence of polynucleated cells with both red and green nuclei was detected by confocal microscopy. Scale bars represent 100 μm. d Fusion index was calculated separately for green polynucleated cells (Fl_Green), red polynucleated cells (Fl_Red), and red/green polynucleated cells (Fl_{Green + Red}). Results are expressed as mean percentages relative to the fusion index calculated for the control condition