Imaging glioma cell invasion in vivo reveals mechanisms of dissemination and peritumoral angiogenesis
Abstract
Infiltration of cancer cells into normal tissue is a hallmark of malignant gliomas and compromises treatment options. A lack of appropriate models limits the study of this invasion in vivo, which makes it difficult to fully understand its anatomy and the role of dynamic interactions with structures of the normal brain. We developed a novel methodology by utilizing multiphoton laser scanning microscopy (MPLSM) to image the movement of glioma cells deep within the normal brain of live mice in real time. This allowed us to track the invasion of individual RFP‐expressing GL261 cells in relation to perfused vasculature or GFP‐labeled endothelial cells repetitively over days, up to a depth of 0.5 mm. Glioma cells moved faster and more efficiently when the abluminal site of a blood vessel was utilized for invasion. Cells that invaded perivascularly were frequently found next to (a) multiple capillary structures where microvessels run parallel to each other, (b) capillary loops or glomeruloid‐like bodies, and (c) dilated capillaries. Dynamic MPLSM for more than 48 h revealed that single invasive glioma cells induced intussusceptive microvascular growth and capillary loop formation, specifically at the microvascular site with which they had contact. As the main tumor grew by cooption of existing brain vessels, these peritumoral vascular changes may create a beneficial environment for glioma growth. In conclusion, our study revealed new mechanisms of peritumoral angiogenesis and invasion in gliomas, providing an explanation for their interdependence.Keywords
This publication has 32 references indexed in Scilit:
- Mechanisms of Disease: the PI3K–Akt–PTEN signaling node—an intercept point for the control of angiogenesis in brain tumorsNature Clinical Practice Neurology, 2007
- Direct Visualization of Macrophage-Assisted Tumor Cell Intravasation in Mammary TumorsCancer Research, 2007
- Alternative Vascularization Mechanisms in CancerThe American Journal of Pathology, 2007
- Transplanted glioma cells migrate and proliferate on host brain vasculature: A dynamic analysisGlia, 2006
- The multiple uses of fluorescent proteins to visualize cancer in vivoNature Reviews Cancer, 2005
- Kinetics of vascular normalization by VEGFR2 blockade governs brain tumor response to radiationCancer Cell, 2004
- Ultrastructural and Morphometric Investigation of Human Brain Capillaries in Normal and Peritumoral TissuesUltrastructural Pathology, 1997
- Modification of Human Glioma Locomotion In Vitro by Cytokines EGF, bFGF, PDGFbb, NGF, and TNFαNeurosurgery, 1995
- Two-Photon Laser Scanning Fluorescence MicroscopyScience, 1990
- Tumor Angiogenesis: Therapeutic ImplicationsNew England Journal of Medicine, 1971