Drug mix hope for cancer therapy

[bongme]

hi

Sunday, 3 March, 2002

Advances in mixing anti-cancer drugs could soon lead to more effective treatment for the disease, scientists say.

Cancer Research UK scientists in Birmingham have gained detailed information about exactly how treatments kill off cancer cells.

They believe using complementary drugs which target cancer cells in different ways could help to stop tumours becoming resistant to treatment, and could replace conventional chemotherapy.

The scientists also managed to restore sensitivity to cancer cells that had already developed resistance by infecting them with a modified virus carrying a powerful "suicide message".

In the future, it might be possible to directly treat cancer cells with death molecules, effectively using them as anti-cancer drugs

Professor Lawrence Young  

Anti-cancer drugs work by flicking a "suicide switch" within each cancer cell. Resistance to the drugs develops when one such switch becomes jammed.

The team focused on ovarian cancer, which often responds to chemotherapy initially before developing resistance to it at a later stage.

The scientists removed cells from ovarian tumours, grew them in the laboratory and treated them with a range of anti-cancer drugs.

They found different drugs activated different cell death molecules.

Such findings should improve their understanding of cell death mechanisms, which could help in the future development of anti-cancer drugs.

Scientists hope that choosing drugs to target several different switches all at once could prevent a tumour from developing resistance to treatment.

Double benefit

Team leader Professor Lawrence Young said: "Our research has allowed us to find out which switches are targeted by different drugs, so that we can learn to mix and match far more effectively than is currently possible."

Professor Young and his colleagues also believe that further research into how drugs cause cancer cells to commit suicide could pave the way for new types of treatment.

They found treating drug-resistant cancer cells with cell death molecules seemed to re-activate suicide switches that had become jammed, restoring sensitivity to chemotherapy.

One cell death molecule which triggers a number of suicide switches is CD95L.

Researchers inserted this into a virus, which they then used to infect drug-resistant cancer cells.

The cell death molecule short-circuited the cells' jammed suicide switches, knocking them into suicide mode even though some of the switches had not been flicked.

Professor Young said: "Suicide switches seem to work by setting off a series of death molecules, which end up killing the cell.

"In the future, it might be possible to directly treat cancer cells with these death molecules, effectively using them as anti-cancer drugs."

Professor Gordon McVie, joint director of Cancer Research UK, said: "Professor Young's research could have a double benefit for cancer patients.

"It should allow doctors to make much better use of existing drugs, by using them in the combinations in which they'll be most effective.

"And it may also lead to a new breed of drugs that work differently from conventional chemotherapy."

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