Tiny, heated "nano-probes" beat cancer in mice

CHICAGO (Reuters) - Tiny, tumor-seeking probes can slow the growth of aggressive breast cancers in mice, leaving surrounding tissue unharmed, U.S. researchers reported on Tuesday.

They said their study, published in the March issue of the Journal of Nuclear Medicine, could offer a new approach to treating cancer.

Researchers at the University of California Davis used heated "nano-probes" -- magnetized iron-oxide particles. They attached these to monoclonal antibodies, which are engineered versions of human immune system proteins that seek out a specific protein.

The result was a tool that could confine the treatment to the tumor while sparing surrounding tissue, said Sally DeNardo, a professor of internal medicine and radiology at UC Davis and lead author of the study.

The probes were developed with scientists at privately held biotechnology company Triton BioSystems Inc. of Chelmsford, Massachusetts.

DeNardo and colleagues infused the probes into the bloodstream of mice with human breast cancers. Once in the bloodstream, the probes latched onto tumor cells.

Three days later, the team applied an alternating magnetic field to the tumor region, causing the tiny magnetic spheres to change polarity thousands of times per second and generating heat.

Mice in the study received a series of magnetic bursts in a single, 20-minute treatment. The result was a slower tumor growth rate with no toxic side effects, the researchers reported.

DeNardo said the system, if proven in human tests, could offer a new weapon for treating cancer.

"This is not just intriguing basic science," she said, adding that the therapy could be combined with other treatments like chemotherapy, to give patients a better shot at beating cancer. "It could have a major impact," she said.