March 07, 2013
Gene Therapy Stops Lung Tumors In Mice

At least in mice lung cancer can be cured with a gene therapy that prevents mutant Myc genes from driving cancers.

Barcelona, 7 March 2013. The study, led by the Vall d'Hebron Institute of Oncology (VHIO), has managed to eliminate mouse lung tumours by inhibiting Myc, a protein that plays a key role in the development of many different tumours. The results, to be published in the journal Genes & Development, confirm that repeated, long-term treatment does not cause side effects. Even more importantly, no resistance to treatment has been encountered, which is one of the biggest concerns with anticancer therapies. These results show that anticancer therapies based on Myc inhibition are a safe, effective therapeutic option in new drug development.

One of the major potential ways to really cure cancer is to send in genes that counteract the effect of the mutant genes that cause cancer. Gene therapy is like a software patch sent in to fix a bug. DNA is like a really complex piece of software. Once we can rewrite the genetic software to cancel out the effects of cancer-causing mutations we will be able to cure cancer.

The work conducted by the Mouse Models of Cancer Therapy group at the VHIO, led by Dr Laura Soucek, shows that Myc can be controlled and inhibited through a mutant called Omomyc that hijacks Myc and prevents it from acting. "Even if we clearly identify a mechanism behind tumour development, it is still extremely complex to pinpoint how to intervene in cells' internal machinery or modify genetic processes," explained Dr Soucek. "We have found a way to inhibit Myc through Omomyc," she continued. "We induced Omomyc expression in mice through gene therapy and managed to activate and deactivate it by administering an antibiotic to the mice in their drinking water."

In the study, multiple lung tumours were induced in the mouse (up to 200 tumours in each individual) and Myc inhibition episodes were achieved by activating Omomyc expression for 4-weeks, followed by 4-week rest periods. This therapy - known as metronomic therapy - was maintained for more than a year, regularly checking tumour progress in each mouse. All mice became tumour free after the first inhibition period, but 63% of cases then relapsed. After the second Myc inhibition period, only 11% of the initial tumours reappeared. According to Dr Soucek, "the most important finding was that there were no signs of resistance to treatment. This is one of the biggest disadvantages of many anticancer therapies: the disease develops resistance and can return even more aggressively."

One of the challenges with gene therapy is to get it into every cancer cell. Another challenge is to do it in a way that does not mess up the genes of normal cells. Since both problems are hard I am surprised these researchers have gotten this far.

Share |      Randall Parker, 2013 March 07 09:17 PM 

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