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3 Dimensional Ex vivo Technique for In situ Tumor Growth

Reporter: Stephen J. Williams, Ph.D.

Brain tumors are both difficult to treat and hard to study because of the organ they affect. The structure of the brain is extremely sensitive to alterations. Until recently the study of architectural alterations and their effects was mostly restricted to in vivo experiments. Typical culturing of brain tissue requires disaggregation and manipulation into a 2-dimensional format, losing any anatomically relevant structure. To study the in situbrain structure, a new technique has been described by researchers from the University of Erlangen-Nürnberg. By carefully sectioning the brains of 4 day-old mice and placing them on a 0.4 uM pore-size transwell membrane 6 well plate insert within required culture medium, they were able to study the endogenous structure under varying conditions. They injected astrocytes or glioma cells with a micropipette into the slices, and investigated the structural changes brain tumors effect in their environment. Termed the Vascular Organotypic Glioma Impact Model (VOGIM), it revealed all the characteristic pathological alterations normally associated with the disease in vivo such as tumor size and borders, vessel length, vessel junctions, and vessel branches, microglia, cell survival, and neuronal modifications. As this method allows for live cell fluorescent observation, they employed the technique to observe cultures treated with the chemotherapeutic Temozolamide (TMZ, Temodal/Temcad^®). Indeed they found reduced tumor growth in treatment groups vs controls, but also revealed surprising reduction in microglial cells in the peritumoral region. Additionally, they were able to observe the lack of response TMZ elicited from microglial in healthy regions of the tissue, despite its overall reduction in vascularization towards normal levels. The VOGIM technique allows for ex vivo study of brain tissue requiring three dimensional measurements, but may also be extended to other tissues with unique morphology such as kidney, liver, and intestine.

Ghoochani, et al. (December, 2015) A versatile ex vivo technique for assaying tumor angiogenesis and microglia in the brainONCOTARGET