Molecule stops fatal pediatric brain tumor

Scientists have found a molecule that stops the growth of an aggressive pediatric brain tumor. The tumor is always fatal and primarily strikes children under 10 years old.

Every year, about 300 children under the age of 10 years old in the U.S. develop a tumor referred to as diffuse intrinsic pontine glioma (DIPG).

"This tumor kills every single kid who gets DIPG within one year. No one survives," said the study's first author. The study is published in Nature Medicine.

"To the best of our knowledge, this is the most effective molecule so far in treating this tumor," said senior author. "Every other therapy that has been tried so far has failed."

Radiation therapy only prolongs patients' survival by a few months, senior author noted.

The lab previously identified the pathway via which this mutation causes cancer in studies with fruit flies, which was published in Science a few years ago.

Researchers believed the pathway would be a good target to thwart the tumor and pushed forward with their molecular studies. In a study they demonstrated mice in the experiment, which had the drug delivered through their abdomen, had an increased survival of 20 days, which is a long time in the life of a mouse. Now the team is working on delivering the drug to the brain stem to see if the effect will be more potent and effective.

To test the molecule, scientists took tumor cell lines from a pediatric patient that was untreated and injected those cells into the brain stem of a mouse. The human tumor engrafted in the brain of the mouse. The mouse was then treated with the molecule while scientists monitored the tumor. The molecule stopped the growth of the tumor cells and forced them to turn into other types of cells, known as differentiation, thereby halting its growth.

This molecule detaches proteins, known as bromodomain proteins, from their binding to a mutant protein, the histone H3K27M, which is present in more than 80 percent of these tumors.

While the molecule itself is not yet available commercially, another similar class of molecules, BET inhibitors, is being tested in clinical trials for pediatric leukemia and other types of tumors. These could be used in a clinical trial for the pediatric tumor, author said.