Roger Abounader and his team at the University of Virginia Comprehensive Cancer Center developed an experimental treatment strategy for glioblastoma using microRNAs, small genetic molecules that suppress multiple genes responsible for tumor growth.
The researchers combined specialized nanoparticles with focused ultrasound and microscopic bubbles to deliver these molecules across the blood-brain barrier, which normally blocks most treatments from reaching brain tumors. Focused ultrasound guided by MRI directs sound waves precisely to the tumor site. The microbubbles temporarily open the blood-brain barrier, allowing nanoparticles carrying microRNAs to pass through and enter the brain.
Glioblastoma kills more than 13,000 people annually in the United States. Current treatment involves surgery to remove as much tumor as possible, followed by radiation and chemotherapy. The disease remains difficult to treat because cancer cells spread into surrounding healthy brain tissue and because the blood-brain barrier blocks most drugs.
Abounader's approach targets multiple cancer-driving genes simultaneously, potentially avoiding the side effects that come from combining conventional cancer drugs. Many molecules involved in cancer growth cannot currently be targeted by available medications.
The team tested the approach in laboratory experiments and animal models of glioblastoma. Their findings showed the microRNA treatment slowed tumor growth and extended survival in the animals tested.
"This new approach could help target numerous molecules that promote cancer growth, including those for which no drugs exist, at the same time to achieve better therapies," Abounader said.
Although the results are encouraging, the strategy remains experimental and requires additional research before human trials. Abounader and colleagues published their findings in JCI, the Journal of Clinical Investigation.