New way to treat a deadly childhood cancer uses drugs already on the market

Receiving a diagnosis of ependymoma, the third most common type of childhood brain cancer, can be devastating. While babies and toddlers are treated with surgery and radiation therapy, current chemotherapy is ineffective and the cancer often recurs.

Remarkably, researchers from the University of Toronto’s Department of Laboratory Medicine and Pathobiology (LMP) have discovered a new way of treating this deadly form of cancer – with FDA approved drugs. 

Dr. Michael Taylor a professor at LMP, along with lead author Stephen Mack and co-authors including Dr. Peter Dirks, also a professor at LMP, published the groundbreaking findings in Nature February 19, 2014.

Their research showed that epigenetics, the packaging of DNA, is the main cause of this cancer rather than mutations in the DNA.

DNA code is comparable to a three-billion letter long set of instructions on how a cell should operate. In this analogy, the majority of cancers are caused by words that are misspelled, added or deleted or entire book chapters that are added or deleted.

However, according to Professor Taylor, “When we look at ependymoma, we don’t find any misspelled words, deleted or duplicated words or book chapters that are missing. Instead, what we find is that the entire novel is written in the wrong font and the DNA is packaged improperly. While epigenetics has been known to play a role in cancer, this is the first time that epigenetics is the prime driver of cancer.”

There are already FDA-approved drugs that can alter the cancer’s epigenetics.

“Usually when you make a discovery you have to make a new drug, but there are already drugs that change the font," said Taylor. "In this case, there are drugs that are the Microsoft Word equivalent of select all and switch to Times New Roman."

The team’s success relied heavily on their ability to grow and study cells from these rare tumours. Once a patient’s tumour is removed from the operating room, its cells are taken to Professor Dirks’s lab to be grown in specialized conditions. The process is so efficient that by the time a child has recovered from surgery, the team has tested the cells and will know whether a specific drug will work.

“I think that’s where this project has been so exciting. Dr. Taylor and Steve Mack made a foundational discovery in this tumour, and we were able to bring our expertise together in growing these live cells to see whether targeting this packaging really had any promise,” said Dirks.

The team is optimistic that this will provide hope for children suffering from ependymoma. Taylor explains, “We hope it will be an effective treatment. One drug doesn’t usually result in a cure, but there are multiple drugs that attack the same mechanism. Even if we can’t cure it, we could use the drug to keep it to a treatable disease like diabetes.”

If the group receives funding, it could take only three to five years to complete a clinical trial.

Katie Babcock is a writer with the Department of Laboratory Medicine and Pathobiology at the University of Toronto.