Virus Used as Cancer Killer: Treatment Triggers Immune System to Kill Malignancies
Seppa, Nathan, Science News
A tweaked virus that invades malignant cells has allowed patients with advanced liver cancer to survive for months longer than usual. Scientists report online February 10 in Nature Medicine that the virus can sabotage tumors and expose them to attack by the immune system.
The virus-based treatment will add a new weapon to medicine's armory of tumor killers, says Ulrich Lauer, a hepatologist at the University of Ttibingen in Germany who wasn't involved in the research. Patients whose cancer has grown resistant to chemotherapy or other treatments might benefit, he says, because the virus's mechanism of killing cancer cells is unusual.
Viruses trigger a prompt immune response. Researchers have been trying since the 1990s to convert viruses into treatments aimed at tumor cells. The new study employs a partially disabled cowpox virus dubbed JX-594 that does not produce full-blown symptoms of the skin disease.
Study coauthor David Kirn, a physician and researcher at Jennerex Biotherapeutics in San Francisco, says earlier tests showed that the altered virus has a potent effect on tumor cells. "It multiplies and blows the cell apart from the inside out," he says. The immune system sees the cell's debris as a Mayday signal and sends sentinels that recognize suspicious tumor proteins and present the proteins to enforcer cells. This triggers an immune attack on other tumor cells.
Kirn and his colleagues identified 30 people with advanced liver cancer that was not treatable with surgery. …