Colon cancer is a global killer. Each year more than one million people worldwide are diagnosed with it; more than half a million die from it. If diagnosed early enough the standard treatment involves surgery, chemotherapy, radiation or targeted drug therapy to destroy the tumors. In many cases this may work. But in some cases, while this approach helps put people in remission, eventually the cancer returns, spreads throughout the body, and ultimately proves fatal.
Now researchers may have identified a protein that causes normal cells to become cancerous, and turn into cancer stem cells (CSCs). This discovery could help provide a new target for anti-cancer therapies.
Cancer stem cells are devilishly tricky. While most cancer cells are killed by chemotherapy or other therapies, cancer stem cells are able to lie dormant and hide, then emerge later to grow and spread, causing the person to relapse and the cancer to return.
In a study published in Nature Research’s Scientific Reports, researchers at SU Health New Orleans School of Medicine and Stanley S. Scott Cancer Center identified a protein, called SATB2, that appears to act as an “on/off” switch for specific genes inside a cancer cell.
In normal, healthy colorectal tissue SATB2 is not active, but in colorectal cancer it is highly active, found in around 85 percent of tumors. So, working with mice, the researchers inserted extra copies of the SATB2 gene, which produced more SATB2 protein in normal colorectal tissue. They found that this produced profound changes in the cell, leading to uncontrolled cell growth. In effect it turned a normal cell into a cancer stem cell.
As the researchers state in their paper:
“These data suggest that SATB2 can transform normal colon epithelial cells to CSCs/progenitor-like cells which play significant roles in cancer initiation, promotion and metastasis.”
When the researchers took colorectal cancer cells and inhibited SATB2 they found that this not only suppressed the growth of the cancer and it’s ability to spread, it also prevented those cancer cells from becoming cancer stem cells.
In a news release about the study Dr. Rakesh Srivastava, the senior author on the paper, said the findings are important:
“Since the SATB2 protein is highly expressed in the colorectal cell lines and tissues, it can be an attractive target for therapy, diagnosis and prognosis.”
Because SATB2 is found in other cancers too, such as breast cancer, these findings may hold significance for more than just colorectal cancer.
The next step is to repeat the study in mice that have been genetically modified to better reflect the way colon cancer shows up in people. The team hope this will not only confirm their findings, but also give them a deeper understanding of the role that SATB2 plays in cancer formation and spread.