Getting Cancer Drugs Into the Brain Is Difficult

A new 'road map' might make it easier

The greatest obstacle to treating cancer that has spread to the brain is the blood-brain barrier, the brain’s natural defense mechanism.

Purdue University scientists have provided the first comprehensive characterization of both the blood-brain and blood-tumor barriers in brain metastases of lung cancer, which will serve as a road map for treatment development. The work was recently published in Oncotarget.

The research was led by Tiffany Lyle, assistant professor of veterinary anatomic pathology, whose work focuses on the pathology of the blood-brain barrier. As the principal investigator of the Comparative Blood-Brain Barrier Laboratory, she and her team have collaborated with scientists at Purdue and the Indiana University Simon Cancer Center.

"Brain metastases occur most frequently in patients diagnosed with breast and lung cancer and melanoma," Lyle said. "These metastases have a devastating survival rate, mostly because it's so difficult to get drugs into the brain tissue because of the blood-brain barrier."

When cancer cells invade the brain, the blood-brain barrier transitions into the blood-tumor barrier, which has been insufficiently characterized in lung cancer until now, Lyle said.

The researchers analyzed blood-brain and blood-tumor barriers in animal models with non-small-cell cancer cells and in human post-mortem tissue. "We wanted to see what changes in the blood-brain barrier were occurring rapidly and which ones were sustained over time," Lyle said.

They observed that one of the sustained changes during the transition from the blood-brain barrier to the blood-tumor barrier was in astrocytes, brain cells with numerous functions. Lyle said that discovery alone will be key when it comes to future treatment development. "Identifying those changes and pinpointing when they occur during the transition will be critical to developing treatment plans and being able to identify where, and when, cancer cells need to be targeted."

Source:EurekAlert! Nov. 12, 2019