Changing the Way We Think About Cancer

22 October 2020

Researchers at the Gillies McIndoe Research Institute (GMRI) in Wellington are changing the way we think about cancer. While standard treatments such as surgery, radiotherapy and chemotherapy target the entire tumour, GMRI are focusing on a small sub-population of cells called cancer stem cells.

Led by renowned Lower Hutt plastic surgeon, Dr Swee Tan, the GMRI research team are investigating ways to manipulate cancer stem cells using a cocktail of repurposed drugs, all of which are already approved for use in other indications.

Brain Tumour Support NZ paid a visit to GMRI this week to receive a presentation from Dr Tan on their work and an update on their clinical trial for recurrent glioblastoma, one of the only clinical trials currently open to New Zealand brain tumour patients.

GMRI’s cancer research stems from Dr Tan’s ground-breaking research into haemangiomas, more commonly known as strawberry birthmarks. These are benign, vascular tumours which affect about 10% of babies. Dr Tan’s team identified that the strawberry birthmarks arise from stem cells in the placenta, and that these stem cells are regulated by the renin-angiotensin system (RAS), the hormone system that regulates blood pressure and fluid balance.

By targeting the RAS pathway, the GMRI researchers were able to manipulate the stem cells and cause them to self-destruct. Using inexpensive, repurposed drugs, they have successfully developed a new treatment protocol for strawberry birthmarks which is cheaper, more effective and produces fewer side effects than traditional treatments.

This research has significant implications for cancers such as glioblastoma (GBM). Glioblastoma stem cells (GSC) are a sub-population of self-renewing stem cells which are thought to be responsible for the tumour’s resistance to radiotherapy and chemotherapy treatment. GSCs are also responsible for tumour recurrence, in much the same way as a queen bee can leave the hive and form a new bee colony elsewhere.

The GMRI researchers have shown that the renin-angiotensin pathway is expressed in glioblastoma (and other cancers). Their hypothesis that regulation of the RAS to control the growth of GSCs could be an effective treatment approach for glioblastoma was the basis for their Phase I clinical trial: “Potential Treatment of Patients with Advanced Cancer by Modulating the Renin-Angiotensin System – GBM”.

The trial has enrolled around 23 recurrent GBM patients so far. It is open to GBM patients who have relapsed and for whom there are no further conventional treatment options or for whom these treatments are deemed not to be beneficial. This patient population has a poor prognosis, typically measured in months, and the challenge has been to keep patients on protocol for a significant period of time to allow the treatment to take effect.

Nevertheless there have been some encouraging signs, with one patient on the trial surviving in excess of 2 years. Based on these promising signals, GMRI are planning another trial for newly diagnosed glioblastoma patients. The second trial would see GBM patients take the cocktail earlier in their disease pathway, possibly concurrent with their conventional treatments of radiotherapy and chemotherapy, giving the experimental treatment more time to work. GMRI are currently seeking funding for this trial.

Any patients wanting to enquire about participation in the the trial should discuss it with their oncologist, specialist or neurosurgeon.