By Linda Weiford, WSU News
How ironic, then, that venom from a scorpion species known as the deathstalker is credited with prolonging the lives of a group of dogs, including three named Whiskey, Hot Rod and Browning.
At Washington State University, clinical trials of “tumor paint,” a product that lights up cancer cells, are proving beneficial in treating canines.
The re-engineered molecule found in the venom of the deathstalker scorpion latches onto malignant tumors, making the diseased tissue glow brightly and distinctly against normal tissues. Consequently, surgeons are better able to detect – and remove – cancerous cells while leaving healthy ones behind.
Saved a leg
Phase 1 of the trials involved administering tumor paint intravenously to 28 canine cancer patients prior to surgery, said William Dernell, professor and chair of WSU’s veterinary clinical sciences.
“These were people’s pets that had developed cancer spontaneously, not in a lab,” he said.
One of those pets was Browning, a then-10-year-old chocolate Lab who underwent surgery at WSU’s veterinary hospital to remove a large sarcoma on her leg. Using tumor paint and an infrared camera, the surgery team was able to remove the cancerous cells that glowed bright green – thereby sparing the leg from amputation, said Dernell, who oversees the clinical trials.
Browning, a hunting dog who lives with her owners in Spokane, was able to return to her outdoor activities.
“The fluorescent substance prefers tumor cells over normal cells, allowing us to define the borders of where a tumor begins and where it ends,” Dernell said. “We’re always hearing about some new compound that targets tumors. From what we’ve seen, this one really does.”
Pediatric oncologist Jim Olson developed and patented tumor paint at Seattle’s Fred Hutchinson Cancer Research Center as a way to help people, but also the pets they love, he said.
“Many animal tumors resemble those that arise in humans so it only makes sense for the two groups to reap the benefits that tumor paint can provide during cancer surgery,” he explained. “As WSU uses the technology to help dogs, the dogs provide information that’s applicable to human cancers.”
Four years ago, Olson launched the Seattle-based company Blaze Bioscience as a way to test and commercialize the technology. Not long afterward, he contacted Dernell about conducting clinical trials at WSU. The results were so promising that the second phase will include enrolled feline patients as well, said Dernell.
If that seems an impressive achievement for a compound whose main ingredient is found in the venomous stinger of a scorpion, then consider this: In September, the U.S. Food and Drug Administration approved tumor paint for study in human trials. The product will be used on an estimated 21 people diagnosed with brain or spine tumors, said Olson.
“I predict that in a decade or so, surgeons will look back and say, ‘I can’t believe we used to remove tumors by only using our eyes, fingers and experience,’” he said. “Those hidden deposits of 200 or so cancer cells? They won’t go undetected.”
Scorpions’ new admirers
They didn’t go undetected in Hot Rod, a 10-year-old pit-bull mix who had skin cancer nodules removed at WSU, or Whiskey, another pit-bull mix who underwent surgery for two large mammary carcinonomas nearly two years ago.
Whiskey remains cancer free, said owner Terry Dillon, who decided to enroll her in the clinical trials after he learned of her diagnosis.
“I was afraid I’d have to have her euthanized, but then they told me about this tumor paint and how it might increase the odds of getting all the cancer out. I said yes, absolutely yes, I’ll sign her up.”
Dillon recently moved to Arizona to care for his aging mother. Whiskey, his caramel-colored dog with deep brown eyes, went with him. As if scorpion venom helping to prolong her life isn’t peculiar enough, now there’s another unusual twist to this story.
Under starlight in Dillon’s desert-landscape backyard, Whiskey chases and pounces on scorpions.
“I’ve even seen her draw them into her mouth. I don’t know how in the world she does it,” he said. “Or why.”