Peter Dirks’ research is proving that not all brain cancer cells are created equal – a key finding that could lead to much-needed breakthroughs in treatment.
As a neurosurgeon, Dr Dirks knows all too well that brain tumours are among the most difficult to treat. As a researcher, his findings are helping to explain why.
Five years ago, he published a groundbreaking paper showing that a small but potent group of cells within a brain tumour are responsible for its growth. “Most of the cells in the tumour do not drive growth,” he explains. “It’s these rare cells with specialized stem cell properties that drive the tumour’s growth.”
The finding raises many crucial questions that he is now trying to answer. Where do the cancer stem cells come from? How do they survive radiation and chemotherapy? And most importantly, can we find ways to destroy them?
“I think my team really sees this as a new hope to gain understanding and find new treatments,” says Dr Dirks, who works at Toronto’s Hospital for Sick Children. “We now have special insight into how cancer is organized. We have in our hands the cell type that seems to be most important within the cancer. Now we have a much better chance of stamping out those cells.”
The Canadian Cancer Society has funded Dr Dirks’ research from the start and continues to do so with 2 separate grants.
With one grant, Dr Dirks recently showed that brain tumours in laboratory mice are also driven by stem cells. “That’s really important because we can now use mice to study the complexities of these stem cells and to find better treatments for humans.”
With his second grant, he is testing drugs now used for other brain diseases to see if they can kill cancer stem cells. He can do this efficiently because he’s developed a system for growing cultures of patients’ cancer stem cells. Now he can inject different drugs into dishes of lab-grown cells and watch what happens.
“We’ve found about 40 drugs that seem to have an activity on those cells. So that’s exciting. The best new drug might actually be an old drug with a new use.” He hopes the most promising drugs will be ready for clinical trials within the next 5 years.
The lab-grown cell cultures might also prove useful in the clinic. Doctors could take a tumour sample from a patient, grow cancer stem cells in a culture dish, and test different drugs on them. “It’s a form of individualized medicine. We have the patient’s actual tumour cells growing in a dish. We could find out fairly quickly which drugs would be most effective for that person. That’s really what we’d like to see happen down the road.”