CHAPEL HILL - University of North Carolina at Chapel Hill scientists have discovered they can shrink -- and in many cases eliminate - human tumors grown in laboratory animals by inhibiting a natural mechanism that prevents tumor cells from dying.
Although not yet tried directly in humans, scientists believe their technique could one day significantly improve survival among patients with many kinds of cancer. They are planning the first human tests, which should begin later this year.
The mechanism they've studied for more than three years involves NF-kappa B, a protein that attaches to DNA inside the nucleus of cells and turns genes on and off like a switch. Doctors use chemotherapy or radiation to kill cancer cells, but the UNC-CH researchers reported two and a half years ago that NF-kappa B kicks in and soon enables many cultured tumor cells to escape death. After developing resistance to the therapy, the cancer cells continue reproducing and show no ill effects from the treatment.
In the latest experiments, the scientists used a novel cancer gene therapy strategy to block NF-kappa B in mice with a natural inhibitor protein known as I-kappa B. Human tumors growing in the mice then became susceptible to chemotherapy and in some cases disappeared altogether following treatment.
A report on the discovery appears in the April issue of Nature Medicine, a scientific journal. Authors - all affiliated with the UNC Lineberger Comprehensive Cancer Center - are Dr. Cun-Yu Wang, a former graduate student and now clinical instructor in endodontics; Dr. James C. Cusack, assistant professor of surgery; laboratory technician Rong Liu; and Dr. Albert S. Baldwin Jr., associate professor of biology.
"Our results are dramatic, and we believe they are going to be
extraordinarily important for therapy of different kinds of cancer," said
Baldwin, associate director of the Lineberger Center. "Although not everything
Contact: David Williamson
University of North Carolina at Chapel Hill