New Research Identifies Paradigm with Tumor Growth, May Impact Mesothelioma Research
New research has shown that while scientists have for years been trying to find a treatment for cancer by forcing the cell’s to die, known as apoptosis, they may have unknowingly encouraged “unrestrained growth of cancerous tumors” instead. In fact, the researchers found that blocking the death of normal cells can actually stop and potentially reverse the growth of tumors. These findings, reported in the May 27th issue of Nature could impact ongoing cancer research in all types of cancer, including patients with mesothelioma and other lung cancers.
Mesothelioma is a rare, aggressive form of cancer primarily caused by exposure to airborne asbestos fibers. Close to 3,000 Americans are diagnosed with the cancer yearly. There is no known cure for the disease.
Cell death helps the body eliminate unwanted cells. A receptor in the body thought to mediate cell suicide in normal cells, called CD95, is activated by specific proteins triggering apoptosis. The researchers at University of Chicago and Northwestern University Feinberg School of Medicine, however, found that CD95 mediates not only apoptosis, but also diverse nonapoptotic functions depending on the tissue and the conditions. They found that when they reduced the activator for CD95 in the cancer cell lines, the tumors stopped growing, and some even died.
“This is a paradigm-shifting discovery,” Ernst Lengyel, MD, PhD, Associate Professor in the Section of Gynecologic Oncology at the University of Chicago Medical Center said. “For 20 years, scientists have tried to use CD95 to kill tumors, but what we showed is that it is actually promoting tumor growth.”
Mesothelioma often has a complex growth pattern making complete surgical removal a very difficult task. Surgery is most often followed by chemotherapy. Mesothelioma, however, has proven to be chemoresistant, rendering many of the current chemotherapy treatments inadequate.
Much more research is needed in this area and specifically researchers need to determine how and when the cells switch the function of CD95 from “death” to “growth.” Clinical studies will be launched to test the theory in combination with chemotherapy. Chemotherapy can induce a stress response during which the concentration of CD95 ligand increases, which may further promote the growth of tumors.
