‘Kamikaze Bacteria’ Self-Destructs to Kill Cancer Cells
Scientists have engineered a self-destructing bacteria that could kill cancer cells in the body.
Researcher Jeff Hasty and his team at the University of California discovered that the bacteria Salmonella, which is best known to cause food poisoning and typhoid fever, can be neutered and modified so that they can kill cancer tumors.
"It's like a kamikaze mission," Hasty said in a report published by The Atlantic.
Salmonella bacteria are capable of surviving without oxygen and somehow thrive in the anaerobic environment inside a tumor.
The idea inspired Hasty and his team to engineer strains of the Salmonella bacteria to produce three types of tumor-killing drugs. One drug will destroy cell walls, one will alert the body's immune system, and one that will kill the cancer cells.
The bacteria were programmed to self-destruct and break open after many of them had clustered together in the same spot. About 10 percent of the bacteria will survive, and they can re-seed the population and trigger more cancer-cell deaths, the scientists said.
In the study, which was published in the journal Nature, the researchers experimented on lab mice and found that after feeding the bacteria to mice that had liver tumors, the engineered bacteria travelled directly to the tumors.
Upon releasing the three cancer-killing drugs, the tumors of the mice stopped growing. And after giving the mice the bacteria in combination with chemotherapy, the tumors shrank in size and the mice's life expectancy grew by 50 percent.
However, some experts have warned about the studies that seemed to work on mouse models but had devastating results on human subjects.
In the late 1990s, David Bermudes from California State University also developed Salmonella strains that could carry cancer-killing drugs to tumors. The experiment worked on laboratory mice and monkeys, but it failed during clinical trials on humans.
"We could show safety but there was no measurable anti-tumor activity," Bermudes said in a report by The Atlantic.
"In mice, the bacteria targeted a wide range of tumors 100 percent of the time. In the human study, they targeted tumors just a third of the time and only at the highest dose. We all know mice don't predict tumor therapies, or we'd have cured cancer already."
Scientists have long been trying to use bacteria to fight cancer cells. Bert Vogelstein at Johns Hopkins University in Maryland had led one of the first experiments in harnessing bacteria to trigger the death of cancer cells, New Scientist reports.
Vogelstein said that Hasty's study could be a "game changer," and that any kind of scientific advancement made against cancers is considered good news.