Researchers at Weill Cornell Medical College have discovered the molecular switch that allows aggressive triple negative breast cancer cells to grow the amoeba-like protrusions they need to move away from a primary tumor and metastasize throughout the body. These findings, published today in Cancer Cell, suggest a novel approach for developing therapies to treat cancer once it has metastasized.
The researchers discovered that a miRNA (a small, non-coding RNA that regulates gene expression) called miR-708 is inhibited in metastatic triple negative breast cancer. miR708 acts as a metastatic tumor inhibitor, and when its function is restored, the tumors do not spread or form lethal macrometastases.
Triple negative breast cancer was chosen for the examination of the role of miRNAs because it has the worst outcome of all breast cancer subtypes due to its high recurrence rate and metastatic spread.
The researchers found that delivering synthetic miR-708 blocked metastatic outgrowth of triple negative breast cancer cells in the lung of mice. That makes miR-708 a promising therapeutic against metastatic breast cancer. Dr. Vivek Mittal, director of the Lehman Brothers Lung Cancer Laboratory at Weill Cornell Medical College and the study’s senior investigator, said that the findings suggest that agents now being tested for lymphoma cancer cells may also help restore miR-708 in triple negative breast cancer.
Dr. Linda Vahdat, director of the Weill Cornell Breast Cancer Research Program, Chief of the Solid Tumor Service and a co-investigator on the study said, “These study results are terrific. It not only offers us an avenue to treat metastatic triple negative breast cancer in the short-term, but also gives us the road map to prevent metastases in the long-run. We are anxious to get this into the clinic, and we are working as quickly as possible towards that end.”