Texas A&M researchers are exploring light and ultrasound therapy to treat melanoma

Researchers at Texas A&M University are collaborating on a new project that studies how ultrasound and light can treat melanomas in pigs.

Recent medical advances have made it possible to shrink and kill cancer cells using light in what is known as photodynamic therapy. However, some cancers, such as melanoma, do not respond well to this new treatment.

“In photodynamic therapy, we introduce a chemical that is absorbed by skin cancer cells. “The chemical only reacts when exposed to a certain type of light, causing new molecules to form that destroy the cancer cells,” said Dr. Vanderlei Bagnato, professor in the Department of Biomedical Engineering.

“We are able to eliminate approximately 95% of lesions in non-melanoma skin cancers using photodynamic therapy. It’s very cost-effective and non-invasive,” Bagnato said. “But treating melanoma with light-based therapy is problematic for several reasons. First, the pigment in cancer cells sometimes interferes with light. Second, melanomas, more often than other skin cancers, tend to grow back and metastasize—or spread to other parts of the body—if they are not completely removed.”

Developing a more effective way to treat melanoma using photodynamic therapy could open doors for low-cost, non-invasive treatments in pigs, humans and other mammals.

“We hope that this project not only advances human medicine, but can also bring photodynamic therapy into veterinary medicine – not only in pigs, but also in other species that develop melanomas,” said Dr. Jennifer Fridley, clinical assistant professor in the University’s Department of Large Animal Clinical Sciences in the College of Veterinary Medicine and Biomedical Sciences and director of the Veterinary Medical Park.

Fighting cancer with light and sound

Photodynamic therapy has recently become the primary treatment of non-melanoma skin cancers due to its low cost and high efficiency.

“There are several ways to deliver the therapeutic drug into the cancer – recently we started using microneedles,” Bagnato said. “They are actually made up of the medication itself, so nothing is left behind when they dissolve into the skin. The entire procedure can be completed in less than an hour and does not require surgery.”

Skin cancer patients with diabetes could benefit from photodynamic therapy.

“Diabetes is very common in the United States and becomes more common with age,” Bagnato said. “People with this condition need to avoid surgery if possible because diabetes leads to poor vascularization – the flow of blood to your body’s tissues. If you have diabetes and skin cancer, photodynamic therapy offers a much safer treatment than surgery with a lower risk of complications.”

For the new study, Bagnato and his research partners will test a combination of drugs, delivery mechanisms and types of light to find out which combinations are most effective.

They will also test another type of wavelength – ultrasound. This sonodynamic therapy is similar to photodynamic therapy but uses sound instead of light.

“When we introduce certain drugs into the cancer cells, they become little reactors that produce tiny explosions when hit by ultrasonic waves,” Bagnato said. “We hope to combine both photodynamic and sonodynamic therapy to more completely eliminate melanomas without the risk of regrowth and metastasis.

“I hope this research can form the basis for further specialized cancer research for pets and other animals at VMBS,” he said.

A legacy of ingenuity

For the new study, researchers will collect skin cell samples from a herd of pigs once owned by Dr. Duane Kraemer, a now-retired VMBS senior professor who was InsdreamParticipation in the creation of CC, the world’s first cloned cat.

“The pigs in this study are prone to developing melanoma but are not actually affected by it,” Fridley said. “In fact, sometimes their melanomas go away on their own, which is one of the reasons why it’s important to check for them.

“When we’re not collecting samples from them, the pigs lead a pretty pampered life,” she said. “Dr. Kraemer comes to visit them sometimes and we even send him and his family pictures so he can see what they’re up to. We are very proud to follow in his footsteps as pioneers of new medical and scientific advances.”