Nanotechnology Zaps Prostate Tumor Cells
By Steven Reinberg
HealthDay Reporter on 04/11/2006
TUESDAY, April 11 (HealthDay News) -- Super-small organic particles loaded with an anti-cancer drug attach themselves to prostate tumor cells and use the chemotherapy to destroy cancer, researchers report.
In experiments with mice, researchers used these custom design "nano-particles" to home in on, and then enter, malignant cells, delivering lethal doses of chemotherapy while leaving healthy cells unaffected.
Tumors shrank dramatically after this type of treatment, the researchers reported, and all of the treated mice survived.
"We were interested in developing a nano drug-delivery system," said lead author Dr. Omid C. Farokhzad, an assistant professor of anesthesia at Brigham and Women's Hospital and Harvard Medical School. "These nano-particles are so small that you can put 500 of them side-by-side, and they are as thick as a human hair," he added.
This small drug-delivery system is able to attach itself to the surface of a prostate cancer cell and then get drawn into the cell, Farokhzad said. "This was effective in eradicating cancer in a mouse model of prostate cancer," he said.
His team's report appears in this week's issue of the Proceedings of the National Academy of Sciences.
In the study, Farokhzad's team created tiny sponge-like nano-particles soaked with the chemotherapy drug docetaxel. The particles were designed to release the drug after dissolving in a cell's internal fluids. The nano-particles were made from materials already familiar to experts, and approved for medical applications by the U.S. Food and Drug Administration.
The advantage of this drug-delivery system is that it can selectively release a large dose of a drug directly into a cancer cell.
"If you were to get that concentration of a cancer drug into the cell through normally administered chemotherapy, you would have to give such a large dose that it would cause dramatic toxicity," Farokhzad said. "The system is designed to limit the toxicity, but increase the efficacy."
"Nano-particle drug delivery can be used not only for other cancers, [but] also for other diseases," Farokhzad added. "The targeting molecule on the surface of the nano-particle is equivalent to the GPS system in your car," Farokhzad said. "You can change that targeting on the nano-particle surface and thereby reprogram it to go to a different destination," he explained.
But before this drug-delivery system is ready for common use, it needs to be tested in larger animals and in human clinical trials, Farokhzad said.
One expert thinks these findings are important.
"This is a very significant paper," said Raoul Kopelman, a University of Michigan Distinguished Professor and Kasimir Fajans Collegiate Professor of Chemistry, Physics and Applied Physics and a member of the Biophysics and the Biological Nanotechnology Center at the University of Michigan Medical School.
"It is a better than expected demonstration of the potency of targeted nano-particles for cancer therapy," he said.
Another important point is the researchers' emphasis on biocompatibility and biodegradability of the nano-particles, Kopelman said.
"Each matrix component is FDA-approved, which does not make FDA approval automatic, but still should accelerate it. Still, a nano-particle bio-elimination study will most probably be required for FDA approval," he said.
More information
There's more on nanotechnology at the U.S. National Cancer Institute.
