A study is suggesting a different way of stopping treatment resistance to radiotherapy in esophageal cancer. Researchers at Trinity College in Ireland are reporting in Oncotarget that a molecule lost from cancer stem cells (miR-17) appears to be important in driving esophageal tumor resistance to radiotherapy.1
The team demonstrated that populations of tumor cells that had higher numbers of cancer stem cells formed larger, more aggressive tumors. They also demonstrated that the cancer stem cells were more resistant to radiation-induced cell death.
Many patients with esophageal cancer receive radiotherapy and chemotherapy to shrink their tumor prior to surgery. Unfortunately, the majority of patients are resistant to various degrees. Currently, there are no tests to identify which patients will respond well to radiotherapy or may be more prone to resistance to radiotherapy.
A genetic analysis revealed that the levels of miR17, a powerful gene-regulating molecule, were particularly low in the cancer stem cells that were most resistant to radiation. In patient samples, miR-17 was found to be much lower in the tumors of patients who did not respond to treatment.
In the lab, the team found that the introduction of a synthetic version of miR-17 into the resistant cells allowed them to become more sensitive to radiation. The researchers hope interest in these findings will spur quick advances. They note that a number of other synthetic miR-molecules are currently in clinical trials for treating other diseases.
1. Nynam-Lennon N, Heavey S, Sommerville G, et al. MicroRNA-17 is downregulated in esophageal adenocarcinoma cancer stem-like cells and promotes a radioresistant phenotype. Oncotarget. 2016 Dec 15. doi: 10.18632/oncotarget.13940 [Epub ahead of print]