Scientists have made astonishing progress in developing a "smart bomb" that can deliver powerful cancer-fighting drugs directly to tumors scattered throughout the body, thus minimizing damage to healthy tissue and easing the wretched side effects of chemotherapy.
The research builds on earlier work that showed that an engineered version of the stem cell could home in on a brain tumor and deliver drugs directly to the target area. But this is the first time that research has shown that the same process might be used to attack cancer that has metastasized throughout the body.
So far the research has been limited to mice, but scientists are hopeful that clinical trials involving humans with advanced cancer can begin reasonably soon, possibly in less than a couple of years.
Karen Aboody, of the City of Hope Cancer Center in Duarate, Calif., said she is very encouraged by experiments that showed a remarkable recovery by mice inflicted with a human cancer and treated with the new process. She is the lead author of a report published in the current issue of the peer-reviewed journal, PLoS One. A second report is scheduled for publication next month in Cancer Research.
Of course, what works for mice may not work for humans, and the scientists must prove that the treatment does no serious harm before they can proceed to clinical trials that would determine whether it does any good. So there's still a long ways to go, but the results in the animal studies are nothing less than remarkable.
Aboody, who began her line of research during a 12-year stint at Harvard University, teamed up with experts at several other institutions, most notably Mary Danks, of St. Jude Children's Research Hospital in Memphis, Tenn., for her latest round of experiments. The work is sponsored by the National Cancer Institute and several research foundations.
It's a perfect match in that St. Jude has been pioneering research into powerful new cancer drugs and City of Hope has been developing a unique delivery system using specially engineered stem cells. The research involves a type of cancer called neuroblastoma, which accounts for up to 10 percent of all childhood solid tumors (excluding blood cancers like leukemia) worldwide. It's a common tumor among children, and most patients with metastatic neuroblastoma die of their disease. Neuroblastoma develops from nerve cells in several areas of the body and is the most common cancer in babies.
There is much interest in a drug called SN-38 that is extremely effective and a potent tool in the fight against cancer, but is hard to administer.
"You can't just pump that through a kid's system," Aboody said. "It's too toxic."
If it could be delivered directly to the tumors, no matter where they are in the child's body, it would do much to alleviate the often fatal impact of neuroblastoma. And that's where the latest research comes in.
Stem cells have shown a remarkable ability to home in on cancerous tissue, possibly because the tissue is damaged, and maybe because the cancerous cells try to produce new blood vessels. Whatever the cause, Aboody recognized that the attraction of stem cells to tumors offered the possibility of building a very precise delivery system.