Rice Univ. bioengineers and
physician-scientists at Baylor College of Medicine and Texas Children’s
Hospital have successfully destroyed tumors of human brain cancer cells in the
first animal tests of a minimally invasive treatment that zaps glioma tumors
with heat. The tests involved nanoshells, light-activated nanoparticles that
are designed to destroy tumors with heat and avoid the unwanted side effects of
drug and radiation therapies.
The results of the new study are available online in the Journal of Neuro-Oncology. The
researchers reported that more than half of the animals that received the
nanoshell treatment for glioma tumors had no signs of cancer more than three
months after treatment.
“This first round of in vivo
animal tests suggests that photothermal therapy with nanoshells may one day be
a viable option for glioma patients,” said study co-author Jennifer West,
the Isabel C. Cameron Professor of Bioengineering at Rice and chair of Rice’s
Department of Bioengineering. West cautioned that follow-up work in the
laboratory is needed before any human testing of the therapy can begin. She
said human clinical trials of nanoshell phototherapy for glioma are likely at
least a year away.
Glioma is among the most aggressive and difficult-to-treat of all brain
cancers. Fewer than five percent of glioma patients survive beyond five years.
The disease is particularly difficult to treat because glioma tumors are often
highly invasive and inoperable.
Study co-authors include pediatric oncologist Susan Blaney, deputy director
of Texas Children’s Cancer
Center and Baylor College
of Medicine professor and vice chair for research in the department of
pediatrics, and Rebekah Drezek, professor in bioengineering at Rice.
West, Blaney, Drezek, and colleagues tested mice with abdominal tumors of
human glioma cells. The researchers injected the mice with nanoshells and
waited 24 hours for the nanoparticles to accumulate in the tumors. A laser of
near-infrared light—which is harmless to healthy tissue—was shined at the tumor
for three minutes. The nanoshells converted the laser light into tumor-killing
heat. All seven animals that received the nanoshell treatment responded, but
cancer returned in three. The other four remained cancer-free 90 days after
“The results of this study are encouraging, and we are cautiously
optimistic that this process may bring us closer to finding a cure for
glioma,” said Blaney, also associate director for clinical research at
Baylor College of Medicine’s Dan
and co-director of The Institute for Clinical and Translational Research.
“This is very exciting, especially given the poor prognosis of the disease
and the importance of finding brain tumor treatment alternatives that have
minimal side effects.”
Gold nanoshells, which were invented by Rice researcher Naomi Halas in the
mid-1990s, are smaller than red blood cells. Nanoshells are like tiny malted
milk balls that are coated with gold rather than chocolate. Their core is
nonconducting, and by varying the size of the core and thickness of the shell,
researchers can tune them to respond to different wavelengths of light.
Houston-based biomedical firm Nanospectra Biosciences, which holds the
license for medical use of Rice’s nanoshell technology, began the first human
clinical trial of nanoshell phototherapy in 2008.
West, a co-founder and director of Nanospectra Biosciences, said the new
glioma study is part of a larger ongoing effort within the Texas Medical
Center to adapt nanoshell
phototherapy for use against a variety of cancers. Researchers at Rice, Texas
Children’s Hospital, M.D.
Center, Baylor College of
Medicine and other institutions are working to develop nanoshell-based
treatments for prostate cancer and pancreatic cancer.
The glioma study was funded by the National Science Foundation, the National
Institutes of Health, and Hope Street Kids.