Fig. 3

Non-mitotic events observed in primary cultures of the second recurrent HPC tumor from Case 1. A Cannibalism through Amoeboid Sequestration: (a) A mononucleate sequestering cell (yellow arrow) adheres to another mononucleate cell. (b) The process of engulfment initiates as the sequestering cell rounds up the target cell. (c-d) Eventually, the target cell gets completely engulfed (dotted circle). (e) This leads to the formation of a single binucleate cell (Additional file 2: Video S1A). B Cytoplasmic shedding and acquisition: (a) Two cells (yellow arrows); where (b-c) one of the cells expels a portion of its cytoplasm (dotted circle). (d) The other cell extends itself to incorporate the shed portion (solid circle). (e) Both cells continue to survive after these events (Additional file 3: Video S2B). C Protrusion-mediated cell detachment: (a) A cell generates a protrusion from its body. (b) The protrusion narrows from one side. (c) Eventually, the cell detaches from the parent body, achieving independent status (Additional file 3: Video S2A). D–F Nucleus Staining with Hoechst 33,342. D (a) Depicts a cell elongating at one end. (b) This elongation causes the membrane to thin from the center, ultimately resulting in detachment. (c) Through staining, it becomes evident that the shed portion of the parent cell harbors nuclei content (dotted circle) (Additional file 3: Video S2I). E Dispersion of nuclear acid materials throughout the cell. Hoechst 33342 staining indicates the presence of nuclear contents not only within the cell nucleus (yellow arrow) but also in other cellular regions (red arrows). F Inter-cellular tunneling for nucleic acid transfer: (a) Tunneling is observed between two neighboring cells (green arrows) suggests that (b) the cells are engaged in transferring nucleic acid materials between each other (Additional file 4: Video S3G). All the scale bars are at 50 µm. Time points in minutes are labelled at the upright corner of each panel in (A–D). The complete videos of these snapshots of live-cell imaging are provided in the Supplementary Materials