New drugs could treat resistant prostate cancers

London, May 2 (IANS) Men with lethal prostate cancer that has stopped responding to conventional treatment could potentially benefit from a new class of medicines designed to overcome drug resistance, a new study suggests.

The drugs, called Hsp90 inhibitors, which are already in clinical trials for several types of cancer, specifically target and inactivate a mechanism commonly used by prostate cancer cells to evade the effects of standard treatment, the findings showed.

The research team found that the drugs countered the effect of malfunctions in the androgen receptor, which often occur in resistance to hormone treatments.

Prostate tumours rely on male hormones called androgens to grow and spread, and blocking androgen receptors can be an effective treatment.

"We have demonstrated for the first time that Hsp90 inhibitors can block the production of the most common abnormal androgen receptors that cause many prostate cancers to stop responding to current treatments,” said study co-leader Johann de Bono, professor at The Institute of Cancer Research, London.

"These drugs are already in clinical trials for several types of cancer, and I am excited that our work suggests they could also benefit men with prostate cancer who have otherwise run out of treatment options," he noted.

The study was published in the journal Cancer Research.

The researchers investigated the effect of the drugs on human cancer cells.

Hsp90 inhibitors are among several innovative new types of treatment designed to attack cancer indirectly, by destabilising multiple different proteins required for the growth and survival of cancer cells.

By destroying several cancer signals at once, they are designed to make it hard for cancers to escape the effects of treatment, giving them promise as potential 'resistance-busting' drugs.

"These drugs can hit cancer harder than those targeting only one protein, and look promising for preventing or overcoming drug resistance,” study co-leader Paul Workman, chief executive of The Institute of Cancer Research, London, said.