Some 90 percent of people who die from cancer do so, say experts, because the disease has metastasized, or spread. Researchers say they believe they can dramatically reduce the mortality rate with a protein combination that kills cancer cells on contact.
Surgery, radiation and chemotherapy are often effective at treating people with a solid tumor, but once the cancer has spread and formed tiny tumors at distant sites, chances for a successful recovery are dismal.
Now researchers at Cornell University in New York have isolated a protein that goes by the acronym of TRAIL that causes metastasizing cancer cells to implode on contact.
The biomedical engineers led by Mike King have attached TRAIL to immune system white blood cells so it circulates throughout the body, ready to destroy.
“And so now, in the blood flow, all of your white blood cells become essentially cancer-killing machines. And whenever they bump into a cancer cell that makes its way in the circulation, that cancer cell will go on to die within a few hours," said King.
King says TRAIL leaves healthy cells alone.
The protein complex triggers apoptosis, or cellular suicide, in cancer cells. Apoptosis is what keeps normal cells from growing out of control.
In initial experiments with TRAIL, King says researchers injected the protein complex into saline but it was only 60 percent effective at killing cancer cells. Researchers say the reason was that there were no immune cells for the suicide protein to latch on to.
When investigators, however, injected TRAIL into the circulating blood of mice with cancer, the therapy was nearly 100 percent effective in causing the metastasized cells to kill themselves.
“We believe the fluid forces, the pressures and forces of blood flow help give the signals to the cancer cells. So basically the fluid flow pushes the cells together, the cancer cell and the altered white cell," said King.
Cancer also commonly spreads through the lymphatic system, which transports clear, colorless fluid containing white blood cells throughout the body. King says bioengineers are also working on a targeted treatment to kill cancer cells that have made their way into lymphatic fluid.
An article describing an experimental treatment for cancer metastasis is published in the journal Proceedings of the National Academy of Sciences.