Immunotherapy: Making it Better
The idea of using a man's own immune system to fight cancer has intrigued scientists for years. It makes perfect sense: The body is supposed to attack harmful invaders, and it does a great job protecting us from most of the germs, viruses, and disease-causing agents we encounter throughout our lives. It even fends off most cancer for decades.
But this idea, called cancer immunotherapy, has not progressed as successfully as scientists had hoped it would. One major hindrance may be a well-meaning but misguided group of cells called regulatory T cells,which shut off the body's immune response.
Prostate cancer is not the only disease enabled by these cells: "The presence of regulatory T cells has been clearly shown in breast and ovarian cancer," says Charles Drake, M.D., Ph.D., assistant professor of oncology. Drake has been named the Phyllis and Brian L. Harvey scholar from The Patrick C. Walsh Prostate Cancer Research Fund to figure out "how common regulatory T cells are in prostate cancer, and whether the presence of these cells predicts how well, or how poorly, a man with prostate cancer will do.
Drake and colleagues, using a mouse model of prostate cancer, have been able to isolate regulatory T cells from prostate tumors. His next step will be to characterize these cells, "with the eventual goal of blocking their function so that immunotherapy for prostate cancer will be more successful." Earlier experiments have provided some clues about how these regulatory cells work, he adds. "They seem to depend on a substance known as transforming growth factorbeta (TGF-β)." Drake will determine whether blocking TGF-β will help immunotherapy for prostate cancer work more effectively. All of this work, in turn, "should provide new insights into the role of regulatory T cells in prostate cancer, and help us to design combination immunotherapy strategies that will be more successful in treating patients."