'Loaded' nanoparticles fight brain cancer

ANN ARBOR, Mich., Nov. 15 (UPI) -- U.S. researchers say they're using nanoparticles -- about one-billionth of a meter in size -- loaded with drugs to kill brain cancer.

In fact, the tiny bits of matter can be harnessed to image and track tumors as well as destroy them, said researchers Wednesday at the University of Michigan Comprehensive Cancer Center.

The researchers said they loaded the minute particles with a photodynamic drug called photofrin and with iron oxide, then targeted cancerous brain tumors. Photofrin works with a type of laser light that activates the drug to attack the tumor, while iron oxide is a contrast agent used to enhance magnetic resonance imaging (MRI).

"Photofrin goes into tumor blood vessels and collapses the vasculature, which then starves the tumor of the blood flow needed to survive," said study author Brian Ross, professor of radiology at the University of Michigan Medical School and co-director of Molecular Imaging at the Comprehensive Cancer Center.

"The problem with free photofrin therapy is that it can cause damage to healthy tissue. In our study, the nanoparticle becomes a vehicle to deliver the drug directly to the tumor."

Photofrin is already being used to treat other cancers like esophageal, bladder and skin cancers, researchers said.

"Thinking outside the box is a must for developing brain cancer treatments. Drugs don't get into the brain when delivered in the normal way, which explains in part why some current treatments for brain tumors are generally not effective. Targeting the tumor vasculature with nanoparticles containing a payload will overcome these issues," said study author Alnawaz Rehemtulla, professor of radiology and radiation oncology at the U-M Medical School.

Results of the study appear in the Nov. 15 issue of Clinical Cancer Research.