A new study has discovered cancer cells' dependence on a unique survival mechanism in order to spread. This new insight on cancer could lead to new tumor-blocking treatments.

Cancer cells can travel from the primary site and around the body. This enables them to "seed" new tumors in various areas. More often than not, the secondary tumors are the ones that cause cancer-related deaths and not the original ones.

These secondary malignant growths are referred to as metastasis, or the spreading of cancer in other areas away from the cancer's primary site. Metastasis is one of the biggest roadblocks in cancer treatments and is currently incurable.

In the past years, cancer research has been working to answer the question as to how cancer cells survive upon leaving the original tumor. Normally, when cells break away and "float," they become vulnerable and die a normal cell death.

"Our research advances the knowledge of how two key molecules communicate and work together to help cancer cells survive during metastasis," said Dr. Stéphanie Kermorgant from the Barts Cancer Institute at the Queen Mary University of London (QMUL). Kermorgant is the study's lead researcher.

How Cancer Spreads

Using cell cultures, mice and zebrafish models, the researchers analyzed the changes that happen to the cancer cells once they leave the original tumor.

They discovered a previously unknown survival method that enables the cancer cell to endure. They also found that the molecules called "integrins" could be the key in enabling the cancer cells to spread.

These are proteins found on a cell's surface. They attach to and communicate with the cell's surroundings.

It is already known that the integrins' "outside-in" and "inside-out" signaling system is helping the cancer cells attach to their surroundings.

The study suggested that during the metastasis process, integrins take on a different role. Instead of their usual adhesion task, they conduct a different kind of communication.

The integrins switch to an "inside-in" signaling system. In this process, the integrins communicate within the cell.

The team found that during the "inside-in" signaling, the beta-1 (β1) integrin partners with a protein called c-Met. Together, they travel inside the cell and go to a location that typically plays a role in the degrading and recycling cell materials.

During the process, however, this location is utilized for a new cell communication process where the beta-1 (β1) and c-Met call out to the rest of the cell and instruct it to fight natural cell death while they float during metastasis.

In the experiment, the research team used both lung and breast cells. They discovered that the likelihood of metastases is lowered when the beta-1 (β1) and c-Met proteins are blocked from moving inside the cell together or when they are barred from moving or reaching the special place within the cell.

The researchers are hoping that the new insights will lead to the development of new drugs that are capable of blocking the spread of cancer throughout the body.

The breakthrough findings were published in the journal Natural Communications on June 23.