Tumor Suppressor May Actually Drive Cancer Development
Scientists from the Cincinnati Children’s Hospital published a study that suggests that blocking a protein normally credited with suppressing leukemia may be a promising therapeutic strategy for an aggressive form of the disease called acute myeloid leukemia (AML). The team’s work appeared online August 27 in the Journal of Clinical Investigation under the title "Transcription factor RUNX1 promotes survival of acute myeloid leukemia cells".
The protein scientists targeted is a transcription factor known as RUNX1, which also plays an important role in helping regulate the normal development of blood cells. The researchers said they were surprised to discover in their laboratory tests that RUNX1 was supporting the growth of AML fueled by fusion proteins.
AML develops and progresses rapidly in patients, requiring prompt treatment with chemotherapy, radiation, or bone marrow transplant. These treatments can be risky or only partially effective depending on the patient as well as the variation and progression of disease. Researchers like James Mulloy, Ph.D., from the division of experimental hematology and cancer biology at Cincinnati Children's and lead investigator, are searching for improved treatment strategies including targeted molecular approaches that could potentially be more effective and carry fewer side effects.
They tested this finding in a genetic mouse model of AML developed by Dr. Mulloy's lab that is driven by fusion proteins and a mixed-lineage leukemic gene called MLL-AF9. The researchers genetically inhibited both RUNX1 and an associated protein called core-binding factor subunit beta. By doing so, they were able to stop the development of leukemia cells, demonstrating the potential viability of RUNX1 as a therapeutic target.
Also collaborating on the research was Paul Liu, M.D., Ph.D., at the National Cancer Institute, who developed a small molecule that specifically inhibits RUNX1. Using this inhibitor, the researchers showed that the AML cells were more sensitive than normal blood cells, indicating the inhibitor may be useful in the future as a therapy for patients with AML.