Scientists uncover protein's key role in breast cancer spread

In collaboration with the Press Association

A protein long known to be involved in cell survival has been shown to play a critical role in breast cancer spread (metastasis) in mice.

The discovery, by US scientists at the Kimmel Cancer Center in Philadelphia, could lead to more effective breast cancer treatment in the future.

The team were studying a protein known as Akt1 which is a known blocker of a process called 'apoptosis' - the mechanism through which damaged cells commit suicide to prevent themselves from becoming cancerous.

Previous research has shown that many cancer types have high levels of Akt 1. But the exact role Akt1 plays in the disease has remained a mystery.

Now new research suggests that it plays a key role in allowing cancer cells to spread around the body.

Lead researcher Richard Pestell and his colleagues genetically engineered breast-cancer-susceptible mice to lack the one or both copies of their Akt1 genes.

They found that mice lacking both copies of Akt1 rarely developed breast cancer.

Mice with one copy of Akt1 in their cells developed small tumours that grew slowly and did not spread.

Mice with two copies of Akt1 developed breast cancers that spread rapidly to the lungs.

Dr Pestell explained: "We proved that there was a requirement for Akt1 in metastasis, which makes Akt1 an exciting target for metastatic breast cancer. We knew that Akt1 could play a role in cell growth and size, but the idea that it could play a role in migration and metastasis was an unexpected new finding."

The team also found out that Akt1 caused cancer spread by triggering the cancer cells to secrete a substance called CXCL16.

"We'd like to find a way of blocking CXCL16 production in human breast cancers," Dr Pestell says. "Right now we are looking at patients' samples to see whether this is important in promoting metastatic breast cancer of other types."

The study is published in the Proceeds of the National Academy of Sciences.