Glioblastoma (GBM) is the most aggressive brain cancer. To model GBM in research,
orthotopic brain tumor models, including syngeneic models like GL261 and genetically engineered
mouse models like TRP, are used. In longitudinal studies, tumor growth and the treatment response
are typically tracked with in vivo imaging, including bioluminescence imaging (BLI), which is quick,
cost-effective, and easily quantifiable. However, BLI requires luciferase-tagged cells, and recent
studies indicate that the luciferase gene can elicit an immune response, leading to tumor rejection and
experimental variation. We sought to optimize the engraftment of two luciferase-expressing GBM
models, GL261 Red-FLuc and TRP-mCherry-FLuc, showing differences in tumor take, with GL261
Red-FLuc cells requiring immunocompromised mice for 100% engraftment. Immunohistochemistry
and MRI revealed distinct tumor characteristics: GL261 Red-FLuc tumors were well-demarcated
with densely packed cells, high mitotic activity, and vascularization. In contrast, TRP-mCherry-
FLuc tumors were large, invasive, and necrotic, with perivascular invasion. Quantifying the tumor
volume using the HALO® AI analysis platform yielded results comparable to manual measurements,
providing a standardized and efficient approach for the reliable, high-throughput analysis of
luciferase-expressing tumors. Our study highlights the importance of considering tumor engraftment
when using luciferase-expressing GBM models, providing insights for preclinical research design.
