Antipsychotic drugs could help fight cancer

22 August 2009

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The observation that people taking medication for schizophrenia have lower cancer rates than other people has prompted new research revealing that antipsychotic drugs could help treat some major cancers.

A preliminary finding in the current online issue of the International Journal of Cancer reports that the antipsychotic drug, pimozide, kills lung, breast and brain cancer cells in in vitro laboratory experiments.

Several epidemiological studies have noted the low rate of cancer among schizophrenic patients. These studies found, for example, that these patients have lower rates of lung cancer than other people, even though they are more likely to smoke.

Genetic factors and the possibility of reduced cancer detection in patients have been considered and over the past decade antipsychotic drugs have been suggested as possible mediators of this effect.

In the new study, pimozide was the most lethal of six antipsychotic drugs tested by a team from UNSW and the University of Queensland. Rapidly-dividing cancer cells require cholesterol and lipids to grow and the researchers suspect that pimozide kills cancer cells by blocking the synthesis or movement of cholesterol and lipid in cancer cells.

Analysis of gene expression in test cancer cells showed that genes involved in the synthesis and uptake of cholesterol and lipids were boosted when pimozide was introduced.

To test the idea that pimozide acts by disrupting cholesterol homeostasis, the researchers combined pimozide with mevastatin, a drug that inhibits cholesterol production in cells. The two drugs were more lethal in combination against cancer cells than when either drug was used alone.

"The combination of pimozide and mevastatin increased cancer cell death," says UNSW researcher Dr Louise Lutze-Mann, a co-author of the study. "We needed a lower dose of each drug to kill the same amount of cells."

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