Thanks to Stem Cells, Esophageal Cancer Can Respond Better to Radiotherapy
Esophageal cancer is one of numerous cancers that impact millions of people in America and across the globe each year. Now, researchers at Trinity College Dublin have uncovered how stem cells can play a role in resolving the notorious tendency of esophageal cancer to resist critical radiotherapy treatments.
Esophageal Cancer and Its Radiation Resistance
Esophageal cancer impacts the esophagus, which runs from the throat to the stomach and is responsible for carrying swallowed food to be digested in the stomach. Most esophageal cancer begins when the cells lining the inside of the esophagus begin to develop DNA mutations that force abnormal cells to collect into tumors that poison other parts of the body. This type of cancer is often indicated by sudden weight loss, difficulty swallowing, chest pressure, and hoarseness. Standard treatments include surgery to remove small tumors, surgery to remove a portion of the esophagus, chemotherapy, and radiation therapy.
However, many esophageal cancers have proven resistant to radiation therapy, which causes sick patients to endure the awful side effects of radiation treatment without gaining any of the benefits. It is believed this happens because cancer stem cells actually acquire and share certain features with healthy stem cells. For instance, normal stem cells can change into any type of cell and repopulate when damaged. This is great when the stem cells aren’t dangerous to the body, but when cancer cells adopt those traits, they are able to support tumor growth even in the face of radiotherapy and chemotherapy.
In the words of lead researcher Dr. Maher, “This work is extremely important in understanding why tumors are inherently resistant to radiotherapy, and how they can acquire resistance. Our findings strongly suggest that it is the cancer stem cell population that we need to destroy if treatment is going to be effective in our esophageal cancer patients.”
Research Findings
Overall, this new research discovered that tumor cells with higher collections of cancer stem cells became larger, more aggressive, and more effective in resisting radiation-induced cell death. As Dr. Maher explained, “Up until recently cancer stem cells were largely considered hypothetical, as there were no clear ways to identify and isolate them. In this study we spent a tremendous effort in identifying tumor cells that had biological markers normally characteristic of stem cells. Once we had identified these stem-like tumor cells, we isolated them and started to pick apart their biology.”
After extensive research, Maher’s team found that cancer stem cells can be categorized into groups based on their sensitivity to radiation. Even more importantly, it was uncovered that one specific gene-regulating molecule known as miR-17 was notably absent from radiation-resistant tumors. When a synthetic version of miR-17 was added into resistant cancer stem cells, they became dramatically more sensitive to radiation efforts. This means that clinical trials could soon be underway to test the practicality of using miR-17 stem cells to help patients more efficiently fight esophageal cancer.
