Gene therapy could 'train' immune system to destroy brain cancer cells

In collaboration with the Press Association

Scientists are developing a new gene therapy approach that 'trains' the immune system to destroy brain cancer cells and may even restore normal brain function.

The approach is being tested on animal models with glioblastoma multiforme (GBM), an aggressive form of brain cancer that often affects concentration, memory and balance as the tumour compresses nerve cells.

Researchers at Cedars-Sinai Medical Centre used a modified virus to deliver two therapeutic proteins directly into tumour cells.

One of the proteins, 'FMS-like tyrosine kinase 3 ligand' (Flt3L), attracted a class of immune cell called dendritic cells to the brain. Dendritic cells clear up dying cells and alert the immune system to the existence of foreign objects, such as cancer cells.

The other protein, 'Herpes simplex virus type 1 thimidine kinase' (HSV1-TK), when combined with the antiviral drug gancyclovir, proved directly toxic to tumour cells.

Publishing their initial findings in the journal Molecular Therapy, the researchers revealed that around 70 per cent of animals survived, compared to just 20 per cent when the dendritic-cell inducing Flt3L was left out.

It is also thought that the therapy could help to revert behavioural abnormalities caused by the growing tumour, as surviving rats did not have any long-term behavioural impairment.

Dr Pedro Lowenstein, director of the centre's Board of Governors Gene Therapeutics Research Institute, revealed: "Tumour growth causes behavioural deficits, but even treatments, such as chemotherapy and radiation therapy, can cause learning disabilities and other cognitive problems.

"In our animal study, this therapy eliminated the tumour mass and reversed the deficits that were caused by the tumour."

It is hoped that human clinical trials will commence later this year.