Decoy molecules drive cancer cells to suicide: study

PARIS, 16 feb 2009 – French specialists on Sunday unveiled a new weapon against cancer -- a molecular "decoy" that mimicks DNA damage and prompts cancerous cells to kill themselves.

The research, published in a US journal, Clinical Cancer Research, opens up fresh avenues for attacking tumours that are resistant to conventional therapy, they said.

Chemotherapy and radiotherapy aim at inflicting sufficient damage to a cancer cell to unleash a process of programmed cell death, also called apoptosis.

But sometimes the onslaught does not cause enough damage to activate the apoptosis trigger, and surviving cancer cells are able to repair themselves.

A team led by Marie Dutreix of the Curie Institute in Paris, developed tiny fragments of DNA that mimic the two broken ends of the double-helix genetic code.

The trick prompts these holdout cells into believing they are far more damaged than they really are, and commit suicide.

The tricksters -- appropriately called "Dbaits" -- have been successfully tested on mice, Dutreix said.

By injecting lab rodents with Dbaits a few hours before radiotherapy, the team were able to wipe out 75-100 percent of cancer cells on lab rodents, compared with 30-50 percent using only radiotherapy, and there was no collateral damage to healthy tissue.

If all goes well, clinical trials on volunteers could start by the end of 2010, said Dutreix.

The technique is especially promising for treating brain tumours and skin cancer, which are notorious for resistance to radiotherapy. If it works, it could also lead to big reductions in dosage of radiotherapy, which can often be toxic to healthy cells surrounding the tumour.