Figure 7. Perivascular glioma cells can hijack control over vasculature tone similar to astrocytes.

Average change in vessel diameters observed in high (h) (95%) oxygen for vessels associated (grey) and not associated (black) with glioma cells when exposed to 100 μM TFLLR or 100 μM TFLLR + 2 μM paxilline (Pax) + 2 μM Tram-34 (a). Changes in vessel diameter for an arteriole associated (grey) and not associated (black) with perivascular glioma cells over the course of one experiment when exposed to 100 μM TFLLR. Changes in Ca²⁺ (ΔF/F) in perivascular GCamp3-GFP-expressing glioma cells were simultaneously measured over the course of this experiment (b). DIC images of vessel associated with glioma cells ((-)Tumor Cells) before and after sufficient exposure to 100 μM TFLLR (left), ((+)Tumor Cells) before and at most constricted time point after application of 100 μM TFLLR (right), red lines indicate position of diameter measurement and vessel diameter before drug application, blue arrows indicate vessel diameter, Scale, 10 μm (c). Statistical data provided in results section, error bars refer to SEM. Acute slices from mice bearing GCamp3-GFP-expressing D54 gliomas that also expressed the red fluorescent protein tdTomato were loaded with DMNPE-4 caged Ca²⁺. [Ca²⁺]_i uncaging in TdTomato-positive glioma cells located at arterioles resulted in vascular responses (n=3), this example shows a dilation (d) Scale, 20 μm. Traces showing a fast [Ca²⁺]_I increase preceding the vascular response and slower oscillations at later time points. Data were corrected for dye bleaching using the bleach correction macro for ImageJ. (e).