His cancer 'challenge'

February 24, 2009|By Robyn Shelton, Sentinel Medical Writer

James Turkson was in college in the 1980s when cancer took his mother. He turned the loss into a challenge.

From a laboratory at the University of Central Florida, Turkson is working on drugs that interfere with a protein called Stat3 that is key to many cancers.

In healthy cells, the protein plays a useful role in the immune system, cell growth and other functions. It essentially serves as a master switch that regulates genes, turning them off and on as needed.

But something goes wrong in cancer cells, where Stat3 inexplicably gets stuck in the 'on' position. As a result, Turkson said, the protein helps feed tumors, shield them from the body's natural defenses and spread the disease to new organs.

"It's this persistent activation that allows the tumor cells to proliferate," said Turkson, 47, an associate professor at UCF.

That's why his team is focusing on drugs that shut down Stat3. In early testing with mice, two compounds developed by Turkson have shown promise in stalling breast cancer tumors. He plans to pit the medicines against ovarian and pancreatic tumors in future studies. He said drug companies already have expressed an interest in the potential medicines.

Stat3 has become a popular focus in cancer research. Other scientists have found that it's abundant in skin moles poised to become malignant and it's crucial to lung, colon, stomach and bone cancers, just to name a few.

By targeting Stat3, scientists think they even might be able to prevent the disease.

"If you can identify pre-malignant lesions and treat them with a Stat3 inhibitor, you are basically going to be able to stop [cancer] before it starts," said John DiGiovanni, a researcher who studies the protein at the University of Texas M.D. Anderson Cancer Center.

The work is gratifying to Turkson, who comes from the poor African nation of Ghana, where his mother died only weeks after doctors diagnosed her abdominal pain as uterine cancer.

Turkson, who holds degrees in biochemistry and pharmacology, joined UCF in 2005.

His two compounds work by binding to the surface of Stat3 molecules and disrupting their cancer-spurring abilities. In studies published in scientific journals, Turkson and his colleagues have shown that breast tumor growth is stopped in mice treated with the drugs. In contrast, tumors grow steadily in mice that don't get the protection.

For now, both compounds are contenders for additional research. Turkson expects one to emerge eventually as a better choice.

Turkson thinks drugs that focus on Stat3 could play a big role in treating many cancers someday, including the one that killed his mother.

"It was [her death] that sort of set this sense in me that maybe there's something I could do to fight cancer," he said. "It became my own personal challenge."

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