Faculty Focus: Tom Quinn
Leading the fight against skin cancer
Tom Quinn is working to find a treatment for melanoma cancer. Photo by Ginny Booker
Despite a vigorous immunological response from the human body, melanoma cancer is lethal. Once a melanoma tumor becomes metastatic, the chances of survival are extremely poor. Most patients do not live for more than a year after diagnosis.
For several years, researchers have investigated methods to treat melanoma cancer. Now, for the first time, biochemists at the University of Missouri have designed a radio-labeled drug that will bind to and enter cancerous melanoma tissue without breaking down.
Tom Quinn leads one of only two groups in the United States that works with Bismuth-212, an alpha particle that emits a radioactive isotope used to target specific cancerous tissue. After conducting in-vitro studies, researchers in Quinn’s lab applied the metal to the surface of mouse melanoma cells and found that after binding to the cell’s receptors, the isotope entered the cell without breaking down.
“Our effort was a rational design approach because a lot was known about which peptides target molecules present on melanoma cells,” says Quinn. “We simply needed to find a sequence that the cells wouldn't destroy. The drug stays in the tumor probably because of the unique combination of metal bond to the amino acids.”
Preliminary studies in melanoma-bearing mice showed that the radiopharmaceutical was internalized by tumor tissue without breaking down. The success of the project precipitated collaboration between Quinn and AlphaMed, Inc., a pharmaceutical company that has received a $500,000 grant from the National Cancer Institute to develop a radiotherapeutic drug to treat metastatic melanoma. AlphaMed and Quinn’s laboratory at MU will begin to test the therapeutic properties of the bismuth-212 radiopharmaceutical in melanoma animal therapy studies.
The bismuth radioisotope emits an alpha particle, which Quinn and AlphaMed scientists believe will be effective in destroying cancerous melanoma cells. Human clinical trials could begin in two-to-five years, Quinn says.
Quinn says radio-labeled drug development is important because it offers a new approach in the fight to cure melanoma metastases. Also, because the drug selectively targets the cancerous tissue, there is less toxicity to healthy tissue. Quinn predicts that melanoma cancer could be effectively treated in the future with a combination of chemotherapy and targeted radiopharmaceutical therapy.