Jamie Morton is the NZ Herald's science reporter.

Is cannabis a cure for brain cancer?

There's little scientific evidence to suggest whether cannabis can make a difference. Photo / iStock
There's little scientific evidence to suggest whether cannabis can make a difference. Photo / iStock

Is cannabis a cure for brain cancer?

Despite its high profile in the media as a potential agent, there's little scientific evidence to suggest whether it can actually make a difference.

With a just-awarded grant, and the unique advantage of having human brain cancer cells to study, a team of University of Auckland researchers hope to get to the bottom of the issue.

Associate Professor Michelle Glass said while preliminary studies examining the link had been interesting, there had been few to draw on so far.

"There are a lot of claims in the public sphere suggesting that cannabis is useful in all sorts of cancers, but the science not always supporting these claims."

It had been a confounding area for researchers to tackle, as cell or animal based studies were not always translated to more complex human models.

"There has been some preliminary cell-based data, but it's not always on human cell lines, and often on models of cancer which don't always translate," she said.

"I don't think for a minute, on the basis of what we've seen so far, that cannabis is going to be the answer per se."

Cannabis itself is made up of a number of different compounds, but the key psychoactive ingredient (THC) targets a receptor in the brain called cannabinoid CB1.

CB1 has been under investigation for a number of years as a possible therapeutic target, and there are now many compounds available that can activate or inhibit this receptor.

Whether a cannabinoid could form an adjunct treatment to some existing therapies remained an open question.

In studies focused on the cannabinoid ligands that targeted the cannabinoid receptors in cancer cells, outcomes had been mixed, with some reports of tumour cell death, but others recording an increase in cell proliferation, which drives cancer.

Associate Professor Michelle Glass, of Auckland University, will investigate whether cannabis has any use in the treatment of brain cancer. Photo / Supplied via Auckland University
Associate Professor Michelle Glass, of Auckland University, will investigate whether cannabis has any use in the treatment of brain cancer. Photo / Supplied via Auckland University

In a two-year investigation with colleagues Dr Scott Graham and Dr Graeme Finlay, Glass will look specifically at whether the number of CB1 receptors might influence whether the signal produced by the actual activation of the receptors is beneficial or not.

"So what we want to look at is what signalling pathways are being driven when the receptors are activated, and can we actually use what we know about the ability of drugs to drive those pathways to skew it toward a therapeutic use - or potentially identify those patients who might be more likely to have a positive outcome."

The study would be carried out using human cancer brain cells collected by the Auckland Cancer Society Research Centre.

Glass felt finding an answer was important, given the internet was crowded with websites dubiously touting cannabis as a solution.

"It's important that people aren't being given false hope, but equally, if there are situations in which targeting this receptor might be useful, it would be amazing to be able to do that."

The study, which has received a $157,000 grant, was one of 11 awarded a combined $1.3 million by the Auckland Medical Research Foundation.

The focus of other supported projects, announced yesterday, ranged from other cancer projects, heart health, infection and immunity to neuroscience studies, reproduction and newborn health.

"It is really pleasing to see such great research projects and talent across the full spectrum of medical science," said the foundation's executive director, Kim Williams.

"More research is the only way we can ensure genuine advances in medicine and outcomes for patients."

Other funded studies

• Beating drug-resistant bugs:

University of Auckland researchers will investigate whether a recently discovered class of compounds might help restore the effectiveness of antibiotics against drug-resistant bacteria.

The team will find if activity of the antibiotic doxycycline can be enhanced towards the normally drug-resistant bacterium Pseudomonas aeruginosa -- and ultimately whether such compounds can be used to "rehabilitate" old antibiotics.

• Helping brain recovery in preterm babies:

Restoring normal levels of a molecule critical for normal brain growth, called insulin-like growth factor (IGF-1), might be key to recovering normal brain development in pre-term babies with impaired brains.

An Auckland University team will test whether restoring IGF-1 levels during or after an infection will promote brain maturation, and thus return development.

• Drugs to stop cancer growth:

Auckland University and Auckland Cancer Society Research Centre scientists are developing drugs to target changes that occur when poorly-developed blood vessels can't deliver enough oxygen to breast cancer tumours, resulting in hypoxia.

This causes cancer cells to become more invasive, increasing the risk of spread, and occurs because certain enzymes sense low oxygen and respond by switching on genes that promote invasion.

The team will investigate the potential of their new drugs to prevent hypoxia signalling in tumour models and reduce tumour growth and metastasis, improving survival.

• Targeting post-surgery heart risk:

A study led by Auckland District Health Board will determine the incidence and consequences of atrial fibrillation - an abnormal heart rhythm characterised by rapid and irregular beating - following surgery.

Patients will wear a heart monitor before and after surgery, and will also undergo an MRI scan of their brain several days after surgery looking for any evidence that they have had a small stroke.

The study may change the treatment of patients who have an episode of atrial fibrillation after an operation, to protect them from complications such as stroke.

- NZ Herald

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