Designer Molecule That Wages Two-pronged Attack on Skin Cancer Identified

by VR Sreeraman on Nov 4 2008 12:25 PM

A novel designer molecule, created by researchers at the University of Bonn, can attack malignant melanoma via two completely different routes.

In the first route, the substance makes use of its structure, which is quite similar to components of viruses, to alert the immune system. At the same time, the own defences of the body are also strengthened against cancer cells.

The molecule also puts pressure on the tumour in a different way, and turns off a specific gene in the malignant cells, which ultimately leads them to suicide.

Thus, by using this two-pronged strategy, scientists have been able to fight metastases in the lungs of mice suffering from cancer.

For the study, the researchers resorted to a method called RNA interference, in which small RNA molecules can be used to target certain genes and switch them off.

"We used this method in order to drive the tumour cells to suicide," Nature magazine quoted the Bonn dermatology researcher Professor Thomas Tuting as saying.

The scientists explained that each body cell is equipped with a corresponding suicide programme, which gets activated if the cell becomes malignant. But it dies before doing any more harm.

"But in tumours a gene is active that suppresses this suicide programme. We have pinpointed this gene and switched it off by using RNA interference," Professor Tuting.

In fact, the scientists in the study also tried to deal with cancer by another route.

"We basically "disguised" our RNA. That is why the immune system took it for the genetic makeup of a virus," said Professor Gunther Hartmann, director of the Institute of Clinical Chemistry and Pharmacology.

There are many viruses that use RNA to store information, thus, if the body discovers RNA fragments, which it takes to be the genetic makeup of a virus, it prepares an attack on them.

In this way, the body's defences were prompted to tackle the tumour cells far more aggressively than normal.

'The beauty of this method is that we can attack the cancer with one designer molecule along two completely different routes. This way the tumour is deprived of opportunities of sidestepping the attack that make successful therapy so difficult in other cases,' said Professor Hartmann.

After conducting initial experiments in mouse models, the researchers found that the new molecule significantly inhibits growth of metastases in the lungs. The therapy even led to the secondary tumours becoming smaller or even disappearing entirely.

The study is published in the latest issue of Nature Medicine's.