Nanocarriers are microscopic synthetic particles that can deliver therapeutic drugs to a required area in the body. Now a group at the Lawrence Berkeley National Laboratory say they have developed a new class of nanocarriers, prompting optimism in the long fight against aggressive cases of glioblastoma multiforme.
A collaborative effort between a polymer scientist at Berkeley lab, Ting Xu; a University of California Davis scientist, Katherine Ferrara; and two researchers at UC San Francisco, John Forsayeth and Krystof Bankiewicz, led to the invention of a class of nanocarriers dubbed "3HM," referring to its coiled-coil three-helix micelle structure.
The size and stability of the particles are sufficient to deliver a drug to GBM tumors. Importantly they showed that by attaching the 3HM particles to a radioactive metal to aid imaging, they could watch it pass through the blood-brain barrier (BBB), a physical barrier that has halted a number of drugs from reaching their desired target in the brain.
They also find the 3HM particles add up at the GBM tumor at twice the concentration as the best FDA-approved nanocarrier.
"Our 3HM nanocarriers show very good attributes for the treatment of brain cancers in terms of long circulation, deep tumor penetration and low accumulation in off-target organs such as the liver and spleen.
"The fact that 3HM is able to cross the blood brain barrier of GBM-bearing rats and selectively accumulate within tumor tissue, opens the possibility of treating GBM via intravenous drug administration rather than invasive measures. While there is still a lot to learn about why 3HM is able to do what it does, so far all the results have been very positive," says Xu, who is the lead author in the study.
The group used the GBM tumor model to study their nanocarrier since these tumors are notoriously aggressive and most treatment fails to improve survival. These cancer cells form from glial cells that are the support cells of the brain and undergo cell division thereby being vulnerable to abnormal cell growth and cancer.
Treatments consist of radiotherapy, surgical intervention and chemotherapy, and although many drugs that might be effective against the cancer, they cannot bypass the BBB. The ones that do are usually tethered to carriers. A common carrier used is called a liposome, a ring of lipids that encapsulate the drug, and while these are around 110 nanometers in size the 3HM particle is a mere 20 nanometers--increasing the chance of successful delivery to the brain.
"I thought our 3HM hybrid materials could bring new therapeutic opportunities for GBM but I did not expect it to happen so quickly," says Xu, who has been awarded a patent for the 3HM technology.