The mechanism that makes fireflies glow through a process called bioluminescence can be used to study tumor response to therapy as well, researchers have found. Led by Barjor Gimi, PhD of Dartmouth-Hitchcock's Norris Cotton Cancer Center [and Adjunct Associate Professor of Engineering] and Ralph Mason, PhD from The University of Texas Southwestern Medical Center at Dallas with first author Li Liu, PhD, the team published the findings in their paper "Dynamic bioluminescence and fluorescence imaging of the effects of the antivascular agent Combretastatin-A4P (CA4P) on brain tumor xenografts," in Cancer Letters.

"By using a model of multiple tumors in the same animal, we established a platform for more efficient studies requiring fewer animals," explained Gimi. "Another benefit of the multiple tumors-same animal model is that it provides more consistency in interpreting results."

Bioluminescence has a major role in small animal research, and the technique has been widely applied in tumor models. The multiple tumor approach can also be used for high throughput screening of a vast range of anti-cancer drug therapies.

In this study, investigators used dynamic bioluminescence imaging to study the effects of a tumor vascular disrupting agent, provided by OXiGENE, known as CA4P on subcutaneous 9L rat brain tumor xenografts in mice. A single dose of CA4P induced rapid, temporary tumor vascular shutdown, as revealed by a rapid and reproducible decrease of light emission. The vasculature showed distinct recovery within 24 hours post therapy, and multiple tumors behaved similarly.

"The beauty of using bioluminescence is that it is relatively inexpensive, has no background signal, and has been validated against other imaging modalities," said Gimi.