HOUSTON, March 1 (Xinhua) -- U.S. scientists have found a new way to deliver cancer drugs that can reduce the size of ovarian tumors by as much as 83 percent and stop tumor growth in ovarian cancer tissue that is resistant to chemotherapy.
Researchers at the Methodist Hospital, University of Texas MD Anderson Cancer Center and Weill Cornell Medical College have developed tiny nanoparticles that maneuver through the bloodstream to carry cancer-battling drugs to tumors, according to the latest issue of Texas Medical Center News, published online on Friday.
Upon arriving at a cancerous tumor, a nanoparticle releases drugs that will bind to the tumor and fight the cancer.
The study, conducted in mice, will be featured in an upcoming issue of the journal Clinical Cancer Research.
"Drug resistance is a huge problem," said Mauro Ferrari, one of the senior authors of the paper. "New approaches to overcoming drug resistance are urgently needed to improve the survival of cancer patients."
To address the problem, the research team decided to use a weapon known as small inhibitory RNA, a snippet of genetic material that interferes with the expression of genes -- in this case a gene that plays a major role in ovarian cancer, according to the report.
Researchers intend to use small inhibitory RNA to stop the cancer cells from growing, and eventually kill them. But small inhibitory RNA can't be injected into a patient because it's very fragile, and enzymes in the blood and inside cells would destroy the RNA before it could reach the cancer cells.
MD Anderson researchers clad the small inhibitory RNA in a protective cloak made of fat cells. However, most of the RNA didn' t last very long in the blood.
Then, researchers at Methodist developed disc-shaped nanoparticles made of silicon that bind to the outside of cancer cells. The researchers then put the small inhibitory RNA, cloaked in fat cells, inside the silicon nanoparticles and injected them into the mice.
Over the next six weeks, 12 injections of 15 micrograms of nanoparticles appeared to reduce the ovarian tumors by 83 percent, according to the report.
Researchers decided to take it a step further. They added the common chemotherapy drug paclitaxel, trade names Taxol and Onxal, inside the nanoparticles. With the drug added, the researchers saw zero tumor growth. Furthermore, the existing tumors began to disappear.
"We can completely eliminate tumor nodules, which means the patients -- in this case mice -- can achieve long-term survival," said research team member Haifa Shen, with Methodist's research institute.
The next step is to test the therapy in humans, according to Texas Medical Center News.