Fig. 5: p53 deficiency dictates oocyte-like large cell formation.

a Representative bright-field images of paired p53^+/+ and p53^−/− HCT116 cultures were shown. The oocyte-like large cells were frequently observed in p53^−/− HCT116 cultures (especially >25 μm in diameter). The oocyte-like tumor cells larger than 25 μm in diameter were counted under high-power microscope in p53^+/+ and p53^−/− HCT116 cultures (n = 6). The relative ratio of ZP3⁺ cells in p53^+/+ and p53^−/− HCT116 cultures were analyzed by flow cytometry (n = 5). **p < 0.01. b Representative bright-field image of an oocyte-like cell with zona pellucida-like membrane (arrow) in p53^−/− HCT116 cultures was shown. c The immunoblotting showed the expression of meiosis entry related protein SCP3 in p53^+/+ and p53^−/− HCT116 cells. The oocyte-like tumor cells with GV-like structure (arrow) or polar body-like structure (arrow head) was detected in p53^−/− HCT116 cultures. d Immunostaining showed the expression of Oct4 and Vasa in oocyte-like large cells of p53^−/− HCT116 cultures. e Bright-field images showed oocyte-like cell appeared in RKO or LNCaP cells with p53 knockdown. The p53 immunoblotting was shown in RKO or LNCaP with control and p53 knockdown. The relative ratio of oocyte-like large cells or ZP3⁺ cells in RKO or LNCaP with control and p53 knockdown was analyzed by flow cytometry (n = 3). *p < 0.05, **p < 0.01. f Multiple single-cell clones were selected from p53^−/− HCT116 cells transfected with p53 for immunoblotting assay. The relative ratio of oocyte-like large cells (n = 9 and 12) and ZP3⁺ cells (n = 5) in p53^−/− HCT116 cells with or without p53 restoration from multiple single-cell clones were analyzed. *p < 0.05, **p < 0.01. Bright-field image showed the appearance of apoptotic cells in the p53^−/− HCT116 with p53 restoration (scale bar = 20 μm)