Researchers at the University of California have identified an enzyme that controls the spread of breast cancer. The findings offer hope for the leading cause of breast cancer mortality worldwide. An estimated 40,000 women in America will die of breast cancer in 2014, according to the American Cancer Society.

The researchers state that they have found a way to target breast cancer metastasis through a pathway regulated by an enzyme.  The enzyme, called UBC13, was found to be present in breast cancer cells at two to three times the levels of normal healthy cells. Although the enzyme’s role in regulating normal cell growth and healthy immune system function is well-documented, the study is among the first to show a link to the spread of breast cancer.

Specifically the team found that the enzyme regulates cancer cells’ ability to transmit signals that stimulate cell growth and survival by regulating the activity of a protein called p38 which when ‘knocked down’ prevents metastasis. Of clinical note, the researchers said a compound that inhibits the activation of p38 is already being tested for treatment of rheumatoid arthritis.

In their experiments, scientists took human breast cancer cell lines and used a lentivirus to silence the expression of both the UBC13 and p38 proteins. These altered cancer cells were then injected into the mammary tissues of mice. Although the primary tumours grew in these mice, their cancers did not spread.

Primary tumours are not normally lethal.  The real danger is cancer cells that have successfully left the primary site, escaped through the blood vessels and invaded new organs. It may be only a few cells that escape, but they are aggressive.  The study shows that the medical community may be able to block these cells and save lives.

The researchers have also defined a metastasis gene signature that can be used to evaluate clinical responses to cancer therapies that target the metastasis pathway.

Source:  UC San Diego Health System