Behind the science: Associate Professor Josh McCarroll

The brain’s natural defence mechanisms make treatment of brain tumours extremely difficult. One researcher with a very personal childhood cancer connection is hoping to change that.

The human body has evolved so that the brain is protected at all costs. Between the brain and other systems, including the blood system, there is a highly protective barrier that prevents toxic substances entering the brain.

Tragically, for children suffering brain cancers such as medulloblastoma, this means it is also extremely difficult to treat brain tumours with traditional drugs that have proved effective in other parts of the body.

Most chemotherapy drugs have difficulty in penetrating the blood-brain barrier. So, for children suffering medulloblastoma, their body must be loaded up with massive amounts of such drugs in order for them to have an effect on the brain tumour.

“If you do want to get the drug crossing to the brain tumour, you have to use high concentrations for it to have an effect, but the consequence of that is long-term side effects for these kids,” says Associate Professor Joshua McCarroll, Team Leader of the Gene Therapeutics and Drug Delivery group at Children’s Cancer Institute and the Australian Centre for NanoMedicine, UNSW. Joshua is also a survivor of childhood cancer.

“You’ve got some kids at the age of five to ten who may survive the cancer because the treatments are good, but the consequences of those treatments can be terrible,” he says. “The kids can be left with learning difficulties and hearing difficulties, all sorts of problems that seriously affect their quality of life. That’s a really big challenge we’re trying to face.”

Breaching the barrier

With the help of funding from The Kids’ Cancer Project, Joshua is conducting research in the field of nanotechnology to develop a ‘Trojan horse’ that is capable of carrying targeted drugs across the blood-brain barrier.

Read more: Application of gene-silencing nanodrugs to inhibit medulloblastoma growth

“We can design these nanoparticles in such a way to optimise them getting into the brain, and even deliver drugs that can selectively penetrate the tumour cells to deliver more targeted drugs directly to the tumour,” he says.

“The nanoparticles can be used to package a number of drugs, and one particular drug we’re testing is a relatively new class. One of the benefits of this type of drug is that it has high selectivity for its target gene.”

In other words, the nanoparticle can ensure the drug’s entry into the brain, then the drug will actively hunt down the tumour, or the genes that play a role in the tumour’s aggressiveness, which might slow down or stop the tumour’s growth.

A clinical trial, Joshua says, could be just five to ten years away.

The funding from The Kids’ Cancer Project, Joshua explains, is very special for a number of reasons. First, it makes the research possible. Second, the value of the funding is doubled by the Federal Government’s Priority-driven Collaborative Cancer Research Scheme, which matched the funding from The Kids’ Cancer Project dollar for dollar. And finally, it helps Joshua to continue to improve the future for children who have been blindsided by cancer, just as he was.

The scientist’s cancer journey

Joshua was just 12 when he was diagnosed with Hodgkin lymphoma, a blood cancer.

“I usually tell people that the day you’re diagnosed with cancer is the day that particular person, the person they were before the diagnosis, dies,” he says. “But it’s not necessarily a bad thing. A new person is born as they go through the treatment. So from the age of 12, I became a different person. Cancer became a part of my life and today I’m trying to give back to others who share that with me.”

“I’m very passionate about the toxic side effects and the long-term toxicity from the treatments. And I understand this topic, because I had to suffer some of them as well. With brain cancers, which are some of the nastiest cancers, long-term toxicity is a really big problem. So I think any sort of treatment we can develop that can minimise that toxicity has to be a very good thing.”

On the lighter side, being a practitioner and supporter of childhood cancer research also has its fun moments, such as Pirate Day, for which Joshua has agreed to dress as a pirate to help raise funds.

“I’m thinking I will definitely have to wear a pirate’s hat,” he smiles, before agreeing that he might also be convinced to consider an eyepatch, a sword and a wooden leg.

Register your Pirate Day today!

Pirate Day is a national fundraising day encouraging kids and the young at heart to dress like pirates to raise money for childhood brain cancer research through The Kids' Cancer Project and The Pirate Ship Foundation. 

Participants all around the country are encouraged to host their filibuster fundraiser any time throughout the year. The collaborating charities usually push the boat out for Pirate Day in May however, due to the coronovirus pandemic this year, organisers chose to move the official day for 2020 to Thursday 24 September, which is also World Cancer Research Day.