January 29, 2015 | by Hiu Chung So
Despite advances in surgery, radiation and drug therapy, brain tumors remain particularly challenging to treat. This is due to the tumor’s location, which can limit localized therapies’ effectiveness, and the blood-brain barrier, which blocks many cancer-fighting drugs’ passage from the bloodstream to the tumor site.
City of Hope scientists are currently researching a new method that can overcome these barriers, using nanoparticles that can activate the immune system to attack tumor cells in the brain.
Within these nanoparticles are CpG, small snippets of DNA molecules that can stimulate a localized immune response. The problem with CpG is that, when the snippets are administered on their own, they can disperse throughout the body, prompting immune cells to attack healthy tissues as well.
To address this issue, researchers Behnam Badie, M.D., director of the Brain Tumor Program and Jacob Berlin, Ph.D., assistant professor in the Department of Molecular Medicine, came up with the idea of packaging CpGs within carbon nanotubes (CNT), small structures that resemble a bacteria or virus in size. Because their structure mimics those of invasive microorganisms, they should be rapidly taken up by immune cells in the injection site, localizing their attack response.
In animal studies, Badie and Berlin have shown this is the case, and those injected with CNT-CpG had significantly better outcomes than the CpG-only and control groups. In their three-month measurement period, 60 percent of the CNT-CpG group survived versus 0 percent of the other two groups.
Further, the CNT-CpG group also remained tumor-free when injected with new brain tumor cells after the initial treatment, showing that this therapy can provide long-term anti-tumor immunity.
Given the promising results of this novel therapy, Badie and Berlin are working with the Food and Drug Administration to develop the criteria for a phase I trial using CNT-CpG and hope to begin an in-human study in the near future.