Researchers at the Tenovus Centre for Cancer Research at Cardiff University have made a breakthrough in breast cancer treatment by inhibiting the activity of a certain protein that can effectively relieve women who become resistant to breast cancer drugs.
The research, led by Dr Stephen Hiscox of the Welsh School of Pharmacy, suggests that restraining a protein known as Src can save the lives of women who become resistant to breast cancer drugs such as tamoxifen.
Tamoxifen has been extremely successful in treating breast cancer but failed to work for a significant proportion of patients after an initial successful response.
As a result patient relapses as the cancer acquires or possesses resistance to the drug.
The researchers have discovered that inhibiting the activity of a certain protein in the cancer could prevent or even reverse the resistance to tamoxifen.
During the study, the team observed that breast cancer cells grown in the laboratory developed resistance to the drug and largely increased activity of a protein known as Src and by stopping this activity, resistance to tamoxifen can be prevented and even reversed.
"We have previously shown that when breast cancer cells become resistant to medicines such as tamoxifen in the laboratory they become more aggressive with an invasive behaviour," said Dr Hiscox.
"These are characteristics that can be promoted by Src, a protein which we have recently shown to be more active in tamoxifen-resistant than tamoxifen-sensitive breast cancer cells," he added.
In a collaborative research between Tenovus and AstraZeneca, the researchers found that treating the cells with a specific inhibitor of Src activity, AZD0530, could reduce the aggressive, invasive behaviour
"Surprisingly, AZD0530 also made the tamoxifen-resistant cells sensitive to tamoxifen again. In addition, we found that co-treating the cells with a combination of tamoxifen and AZD0530 could actually prevent drug resistance occurring in the first place," he said.
However, Src inhibitor AZD0530, developed by AstraZeneca, is currently in its initial stages of clinical trials and if the trials reproduced effective results it could offer a substantial clinical benefit to a large number of women with breast cancer.
"Whilst little is known about the mechanisms used by breast cancers to become resistant to common therapies such as tamoxifen, it remains a significant clinical problem," said Professor Robert Nicholson, Director of the Tenovus Centre for Cancer Research.
"Therefore the ability to restore sensitivity to therapy, or to even prevent resistance arising in the first place, could be of huge benefit to a large number of breast cancer patients," he added.