Page URL:

'Suicide gene therapy' for prostate cancer shows promise

21 December 2015
Appeared in BioNews 833

A treatment for prostate cancer, combining radiotherapy and a new type of gene therapy, is both safe and effective, a study has found.

The procedure has been given the nickname 'suicide gene therapy' because it makes cancer cells self-destruct, and this process also prompts the immune system to attack the cancerous cells.

The senior researcher behind the study, Professor Brian Butler from the Houston Methodist Hospital in Texas, said: 'We have created a vaccine with the patient's own cancer cells – a treatment that complements, and may even enhance, what we can achieve with traditional radiation and hormonal therapies.'

Professor Butler's team genetically modified the cancer cells to carry out this suicide programme by directly delivering the therapeutic genes into them using an adenovirus (a virus similar to the one that causes the common cold).

The delivered gene is derived from a herpes virus and encodes the protein thymidine kinase. When the modified cancer cells began to produce the thymidine kinase in the patients, they were given an anti-herpes drug that attacked the cancer cells and made them self-destruct.

Although the patient's immune system had been unaware of the tumour cells before this, once they began to be destroyed by the drug, it was alerted to their presence and launched an attack, clearing the cancerous cells.

A total of 62 patients with prostate cancer participated in the study, and they were divided into two groups depending on how far their cancer had progressed. Those in whom the cancer was confined to the prostate received two rounds of the experimental gene therapy. Patients with more advanced prostate cancer received three rounds of gene therapy along with hormonal therapy. All the study participants received radiotherapy as well as the experimental gene therapy.

Five years after treatment, 94 percent of patients in the first group and 91 percent of patients in the second group were free from cancerous cells. The researchers said that these numbers reflected a five to 20 percent improvement in outcome compared to previous tested therapies. The study was published in the Journal of Radiation Oncology.

Prostate cancer is the most common type of cancer in men with one in eight being affected over the course of their lifetime.

Professor Butler said that in future it may be possible to inject the virus straight into the tumour itself and 'let the body kill the cancer cells'.

'Once the immune system has knowledge of the bad tumour cells, if they pop up again, the body will know to kill them,' he told BBC News.

Professor Kevin Harrington from the Institute of Cancer Research, London called the findings 'very interesting', but pointed out that a weakness in the current study was that the viruses used to deliver the therapy cannot reproduce, unlike the next generation being investigated.

'It would be interesting to see this approach used with viruses that could reproduce to see if it makes for a more effective treatment,' Professor Harrington told BBC News.

A randomised controlled phase III trial of the experimental combination therapy is currently underway.

18 June 2018 - by Dr Charlott Repschlager 
Sixty-three novel gene variants linked to prostate cancer in men have been discovered...
26 June 2017 - by Charlotte Spicer 
A new three-in-one blood test could progress personalised treatment for patients with prostate cancer...
11 April 2016 - by Rebecca Carr 
A gene therapy for children with a rare but life-threatening genetic disorder that severely weakens the immune system has been recommended for approval by the European Medicines Agency...
7 March 2016 - by Dr Molly Godfrey 
Scientists have identified a method by which all the cells in a tumour could potentially be recognised and eradicated by the patient's own immune system...
9 November 2015 - by Kirsty Oswald 
Researchers have identified the genetic mutations that drive resistance to the hormone therapy abiraterone in patients with advanced prostate cancer...
2 November 2015 - by Dr Jane Currie 
A drug that targets genetic mutations in ovarian cancer has been found to work in men with prostate cancer with similar mutations, according to a new study...
3 August 2015 - by Kirsty Oswald 
Researchers have found that prostate cancer can be divided into five subgroups with distinct genetic fingerprints...
26 May 2015 - by Dr Julia Hill 
Scientists have announced a comprehensive genetic map of prostate cancer, which they say could lead to new treatments for the advanced stage of the disease...
15 September 2014 - by Dr Anna Cauldwell 
Twenty-three genetic variants associated with increased risk of prostate cancer have been identified in a new study, bringing the total number of susceptibility variants for the disease to 100...
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.