New drugs could target protein that fuels breast cancer

A protein which helps breast cancer tumours survive could be targeted with a new type of drug that is already being tested for other cancers, research suggests.

The protein, known as MCL-1, helps breast cancer cells survive by hindering their natural ability to die.

This process, called apoptosis, is the body’s way of getting rid of unwanted, harmful or damaged cells.

However, cancer cells can become expert at avoiding apoptosis in order to survive.

The new study, from the University of Glasgow, confirms that breast cancer tumours rely on MCL-1 to help them grow more aggressively.

It also found that breast cancer stem cells, which are thought to be responsible for the disease spreading and becoming resistant to treatments, are especially dependent on MCL-1 for growth and survival.

Through their research in mice, they were able to show that the growth of tumours was significantly slowed down with BH3 mimetic drugs.

BH3 mimetics are already undergoing clinical trials for some blood cancers.

Professor Stephen Tait, who led the new study at the Institute of Cancer Sciences at the University of Glasgow, said: “Our study further highlights the importance of MCL-1 protein in breast cancer.

“Our demonstration that MCL-1 acts in breast cancer by keeping cells alive (as opposed to other MCL-1 functions) is important, because drugs that target MCL-1 survival function are now in clinical development.

“The next steps will be to determine the effectiveness of MCL-1-targeting drugs that are in clinical development to treat breast cancer in combination with existing therapies.”

The study was funded by the charity Breast Cancer Now in partnership with the Scottish Government’s Chief Scientist Office.

Dr Simon Vincent, director of research, support and influencing at Breast Cancer Now, said: “It’s hugely exciting that this study could confirm the role that the MCL-1 protein plays in allowing breast cancer cells to survive and grow.

“With this understanding, we can now explore targeting the protein with drugs that are already being tested for treating other types of cancer.

“With around 55,000 women being diagnosed with breast cancer every year in the UK, we urgently need to find new ways to treat people and prevent deaths from this devastating disease.

“As such, while further research is needed, we hope this study leads to new and effective treatments being available for people affected by breast cancer.”

The study was published in the journal Cell Death & Differentiation.