Figure 8

Role of connexin-43 in tumor cell attachment to lung endothelium. Immunofluorescence for connexin-43 (Cx43) of mouse lung sections 12 hours after tail vein injection with 4T1-GFP control cells or cells expressing Cx43 variants C61S, G138R, or Cx43OE. Autofluorescence of lung tissue and red blood cells in the green fluorescent protein (GFP) channel (green), Cx43 signal in the Cy5 channel (red), and the nuclear DAPI signal (blue) were overlaid. Panel '4T1' (control 4T1-GFP): Cx43 (red) was upregulated in the tumor cells and in the endothelium of the vessels with tumor cells. Panel 'C61S': tumor cells with C61S mutation, showing similar level of Cx43 expression as for control cells. Panel 'G138R': cells with dominant negative G138R mutation, showing Cx43 (red) around a few tumor cells within the vessels with a limited number of tumor cells in the vessels. In contrast lung segments containing 4T1 tumor cells overexpressing Cx43 show intense Cx43 staining and the vessels contained large number of tumor cells (see panel 'Cx43OE'). The scale bar is 25 μm for all panels.