Nano-bio material shows potential to kill cancer cells, leave healthy cells unharmed
Scientists from Argonne National Laboratory and the University of Chicago's Brain Tumor Center have developed an alternative form of therapy that targets brain cancer cells but does not affect normal living tissue.
Thousands of people die from malignant brain tumors every year, and the tumors can be resistant to conventional therapies. The new nano-bio approach shows promise in lab tests, though it has not yet been tried in animals. In the lab, researchers are able to kill cancer cells by bonding nanoparticles to antibodies that guide the nanoparticles to their cell targets.
This nano-bio technology targets brain cancer cells using inorganic titanium dioxide nanoparticles bonded to soft biological material.
"It is a real example of how nano and biological interfacing can be used for biomedical application," said Elena Rozhkova, a scientist with Argonne's Center for Nanoscale Materials. "We chose brain cancer because of its difficulty in treatment and its unique receptors."
The new therapy relies on a two-pronged approach. It uses titanium dioxide, a versatile, photoreactive nanomaterial that can be bonded with biomolecules. The nanomaterial is paired with an antibody that can recognize and bind specifically to cancer cells. When light is focused on the affected region, the titanium dioxide reacts to the light by creating free oxygen radicals that interact with the mitochondria in the cancer cells. Mitochondria act as cellular energy plants, and when free radicals interfere with their biochemical pathways, mitochondria receive a signal to start the cancer cells' death. Because the antibodies selectively guide the nanomaterial only to cancer cells, the free radical process does not damage normal cells.
"The significance of this work lies in our ability to effectively target nanoparticles to specific cell surface receptors expressed on brain cancer cells," said Maciej Lesniak, Director of Neurosurgical Oncology at University of Chicago Brain Tumor Center. "In so doing, we have overcome a major limitation involving the application of nanoparticles in medicine, namely the potential of these agents to distribute throughout the body. We are now in a position to develop this exciting technology in preclinical models of brain tumors, with the hope of one day employing this new technology in patients."
X-ray fluorescent microscopy done at Argonne's Advanced Photon Source also showed that the titanium dioxide also can attack the tumors' invadopodia - actin-rich, micron-scale protrusions that allow the cancer to invade surrounding healthy cells.
So far, tests have been done only on cells in a laboratory setting, but animal testing is planned for the next phase. Results show an almost 80 percent cancer cell toxicity rate in the hours following a five-minute exposure to focused light.
Rozhkova said that a proof of concept is demonstrated, and other cancers can be treated as well using different targeting molecules, but research is in the early stages.
This work is published in a July 29, 2009 article in Nano Letters and is available online at http://pubs.acs.org/doi/full/10.1021/nl901610f.
The Department of Energy's Office of Basic Energy Sciences, National Cancer Institute, National Institute of Neurological Disorders and Stroke, Alliance for Cancer Gene Therapy, American Cancer Society, and Brain Research Foundation funded the research.
The Center for Nanoscale Materialsat Argonne is one of the five Department of Energy Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories.
For more information about the NSRCs, visit http://nano.energy.gov.