New research about how cancer-related proteins bind copper ions opens up potential new drug targets to treat cancer.
Studies have shown that the level of copper in tumour cells and blood serum from cancer patients is elevated, and the conclusion is that cancer cells need more copper than healthy cells. Higher levels of copper also mean more active copper-binding proteins.
“Therefore, these proteins are highly important to study when it comes to understanding the development of cancer and deeper knowledge about them can lead to new targets for treatment of the disease,” says Pernilla Wittung-Stafshede, Professor of Chemical Biology at Chalmers University of Technology, Sweden and one of the study’s lead authors.
Memo1 and metastatic cancer
Most cancer-related deaths are due to metastases. A protein called Memo1 is part of the signaling systems that cancer cells use to grow and spread around the body. Previous research has shown that when the gene for Memo1 is inactivated in breast cancer cells, their ability to form metastases decreases.
In a new study published in the scientific journal PNAS, a research group from Chalmers examined the Memo1 protein’s ability to bind copper ions through a series of test tube experiments. They discovered that the protein binds copper, but only the reduced form of copper, the one most common in living cells.
Protecting cancer cells
It’s an important discovery because reduced copper, while it is needed in the body, also contributes to redox-reactions that damage – or even kill – the cells. The researchers found that when Memo1 interacted with copper, the metal’s toxic redox reactions were blocked.
“This poses a risk for the tumour to be dependent on a lot of copper because it can provoke chemical reactions that are harmful to the cancer cells. We believe that Memo1, by binding copper when needed, protects the cancer cells so that they can continue to live and spread,” says Wittung-Stafshede.
The researchers now want to move forward with determining the copper ion binding sites in Memo1, and how the presence of copper affects Memo1’s activities in cancer development.
Image caption: The red cancer cell uses the white protein Memo1 to bind the green copper ions. Illustration: Yen Strandqvist, Chalmers.