Metastatic cancer is a frightening prospect. Cancerous tumours are pockets of abnormal cell growth, with a host of environmental and genetic drivers, but metastatic cancer occurs when cells break off from the tumour and spread to other parts of the body.
According to the Cancer Association of South Africa, more than 100 000 South Africans are diagnosed with cancer each year.
Now, researchers from Stanford University in the United States have developed a protein that inhibits the spread of cancer. Their research was published in the journal Nature Chemical Biology this week.
“The majority of patients who succumb to cancer fall prey to metastatic forms of the disease,” says Jennifer Cochran, an associate of bioengineering at the university.
It boils down to proteins – strings of amino acids that govern, cause and catalyse all the biological processes in your body, including cancer.
The Stanford research focused on two proteins, Gas6 and Axl, which are known to initiate the spread of cancer.
Axl proteins can be found on the surface of cancer cells and, when they interact with Gas6 proteins, they enable cancer cells to leave the primary cancer site and move through the blood or lymph to other prime real estate in the body, such as other organs or the lymph nodes.
So the researchers created a “decoy”, a protein that behaves like Axl and can bind with Gas6, but is harmless. “This decoy Axl latches on to Gas6 proteins in the bloodstream and prevents them from linking with and activating the Axls present on cancer cells,” the university said.
“One of the remarkable things about this work is the binding affinity of the decoy protein,” said Greg Lemke, from the Salk Institute’s Molecular Neurological Laboratory and who was not involved in the work.
The “decoy” treatment was tested on mice with ovarian and breast cancer. Mice in the breast cancer treatment group had 78% fewer metastatic nodules than mice in the group that were untreated. Similarly, treated mice in the ovarian cancer group had 90% fewer metastatic nodules than the control mice.
Although this could be an exciting new way to treat cancer without chemotherapy, it may still be years until we see the fruits of this research, which still has to be tested for safety on humans.