Researchers at the UT Southwestern Medical Center in Dallas are among the first to show that bioluminescence imaging (BLI) can be used to determine the effectiveness of cancer drugs that choke off a tumor’s blood supply. The findings are available online and in a future issue of the Journal of the Federation of American Societies for Experimental Biology.
Using BLI, researchers added a molecule substrate called luciferin to the bloodstream of mice with human breast cancer tumors. The tumors had been altered to carry the firefly gene, so they would emit light when the luciferin reached them.
For the study, researchers used BLI to monitor light emissions from tumors following administration of the luciferin. While the mice didn’t visibly glow, the researchers used special light-detecting equipment to observe strong correlations between the amount of light emitted and the size of the tumor as it grew. Detected light emission, however, was severely reduced after the vascular-disrupting drug was administered.
“What we’ve done is offer proof-of-concept that BLI may be an effective and cheaper method to assess drug development and effectiveness,” said Ralph Mason, MD, professor of radiology, director of the UT Southwestern Cancer Imaging Center and senior author of the study. “The technique is not intended to be used for imaging tumors or diagnosing cancer in humans, but it potentially allows us to do much more efficient pre-clinical experiments.”
Mason stressed that light-emission kinetics depend heavily on tumor location.
Although MRI remains the gold standard of medical imaging, BLI has its advantages, he noted. The noninvasive procedure allows detection of cell viability not accessible by MRI and is less costly, according to researchers at UT Southwestern.
“Ultimately, the MRI is much more sophisticated and can do more, but BLI is very straight-forward,” Mason said. “It’s perfect for evaluating new classes of drugs designed to cause acute vascular changes in tumors because the tests are inexpensive and easy to do.”
The team has received a shared instrumentation grant totaling $334,600 from the National Institutes of Health to purchase a commercial bioluminescence imaging system for biomedical research. The system is being used by two dozen research teams at UT Southwestern, according to Mason.
The Department of Defense and the National Cancer Institute funded the study.