How TRAIL Kills Cancer Cells, But Not Normal Cells

摘要

Even when battered by heavy-duty chemotherapy and radiation, cancer cells all too often don't give up. In about half of all tumors, this tenacity stems in part from mutations in the cells' p53 tumor suppressor gene, which render it incapable of performing one of its key functions: activating an internal suicide program after the DNA has been damaged by drugs or x-rays. About a year and a half ago, however, researchers made a discovery that raised hopes that they might still get such mutated cancer cells to kill themselves: Tumor cells are feumore susceptible than healthy ones to another suicide signal, a protein called TRAIL, which acts independently of p53. At the time, though, this hypersensitiv-ity to TRAIL was a mystery. Now three groups, two of them writing in this issue, may have solved the puzzle by showing that normal cells, but not cancerous ones, have a "decoy" protein that can throw TRAIL off the scent.