Fig. 4.

Effects of drug treatment on tumor and brain microvessels. a Collagen IV basement membrane staining. Confocal images of representative intratumoral regions of mice from the four treatment groups at time of death. One extratumoral image of healthy brain tissue is also displayed. Nuclear DAPI staining is shown in blue, collagen IV staining in red (Alexa Flour 546) and GFP-expressing PC14-PE6 tumor cells in green. Vascular basement membrane signal (collagen IV) is additionally shown in single-channel images. Scale bar = 20 µm, magnification 40x. Brightness adjustments were applied equally to all images. b Scatter plot of collagen IV immunostaining inside of metastatic brain lesions. c Scatter plot of collagen IV staining of healthy brain tissue. 3 regions per mouse in 3 mice per group were analyzed. ***p < 0.001, Mann–Whitney-U test. Whiskers indicate minimum and maximum values. (Color figure online)