Fig. 7

Macrophages Transfer Cytoplasm upon Cell Contact with Tumor Cells In Vitro (A) Still images from a movie showing primary macrophages (green) transferring GFP to MC-38 tumor cells (red nucleus, H2B-RFP) via a long tether. (B) Still images from a movie showing primary macrophages (green) transferring GFP to MC-38 tumor cells (red nucleus, H2B-RFP) upon close contact, in which, after the tumor cell divides, one of the daughter cells is obscured by the macrophage, leaving the other tumor cell with macrophage cytoplasm. Time indicated in minutes, and the arrows follow the tumor cell. Arrowhead at 255′ in (A) points to a macrophage which has lost GFP expression concomitant with gain of GFP expression in tumor cell. (C) Cell tracking of tumor cells before (left) and after (right) macrophage cytoplasmic transfer. Each cell is color coded in shades of gray. (D) Cell tracking of tumor cells before (left) and after (right) macrophage cell contact but no macrophage cytoplasmic transfer. Each cell is color coded in shades of gray. (E) Directionality measurements for tumor cells before and after macrophage cytoplasmic transfer in which the ratio of displacement length (dotted gray line) over total distance traveled (solid black lines) was measured and plotted. High ratios indicate high directionality. Error bars are mean ± SD. Non-parametric unpaired t test, p = 0.01 for before and after transfer. Asterisk indicates p < 0.05. NS, not significant. See also Figure S6; Movie S7.