Figure 1.

Astrocytes and microglia are part of gliosis and interact with MCF-7 in the slice cocultures. (A–F) Double staining of the coculture with the organotypic brain slice and MCF-7-GFP (green) in the 3D-tumor plug were applied for astrocytes (anti-GFAP-TRITC = red) and microglia (ILB4-Alexa Fluor 647 = violet), except (A2) is only a single astrocytic staining for better illustration (A1 and A2) The astrocytes form a mesh in the tumor plug contacting the MCF-7 cells with their protrusions. Interestingly, these astrocytes remain connected with other astrocytes and the brain tissue. (B) A lateral part of the brain slice which is adjacent to the tumor plug. In contrast to astrocytes, microglia leave the brain slice as individual cells (A1, B). In the brain tissue, both glial cells are activated at the invasion zone, especially the astrocytes attempt to form a dense barrier in the brain slice next to the tumor plug (C1 and the contact area in higher magnification C2). (D–F) These examples illustrate frequently detectable interactions of astrocytes and microglia with the same MCF-7 cells in the tumor plug. Scale bars represent 50 µm. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]