In order for cancerous tumors to develop several cellular mechanisms must be bypassed or shut down. At least two problematic cellular mechanisms are involved in the development of cancer cells: a mechanism that leads to cell proliferation and a mechanism that causes the cell to become nonfunctional. In order to avoid the development of cancer cells, which continually keep dividing, our body has a mechanism that causes cells to die when they are divided in the absence of external signals. The University of Kentucky scientists identified which part of the Par-4 protein is responsible for triggering this self-destruction of over-dividing cells. This part of a protein, commonly named a “domain”, was found to force cells into self destruction when they sense they have become cancerous. The domain is named SAC, short for Suppressor of ACtin. The team found that over expressing the SAC domain in cancer cells or introducing the domain as a mature molecule to cancerous cells can lead to their degradation.
As the team hoped, the transgenic mouse showed a high resistance to cancer. The mouse had the SAC domain constitutively expressed in every tissue. The researchers tested whether their genetically engineered mouse had higher resistance to cancer than normal mice, and whether or not treatment of this kind is safe- meaning whether the transgenic mouse developed normally. To test its resistance to cancer, the team infected the mouse with cells from a tumor. Indeed, the mouse showed higher resistance rates than normal mice. In the second test, the scientists bred the tumor-resistant mouse with a cancer bearing mouse. The hybrid mouse showed a decreased amount of tumors and the tumors it did have were less violent. All the cancer resistant transgenic mice developed normally and lived a bit longer than normal mice. In conclusion, is seems that the SAC expressing mouse can be considered to be a cancer resistant mouse, and that using the SAC domain to prevent tumors is safe (at least in mice).
The team’s goal now is to develop a cure for cancer based on their finding that a molecule bearing the SAC domain is safe and effective against cancer. Further research must be conducted in order to check the effects of SAC on humans. This method of recruiting our body’s natural defense mechanisms to fight cancer has many advantages over radiotherapy or chemotherapy treatments.
TFOT recently covered some new potential treatments for cancer, which are also based on the body’s natural anti-cancer mechanisms. The first treatment involves using the immune system to fight the cancer cells. Another way to fight cancer, currently being studied by a group of scientists from Israel and the USA, is to block receptors on the surface of the cancer cells.
More information can be found in the University of Kentucky news release.