George Washington University researchers have identified a key molecule in certain kinds of breast cancers that prevent immune cells from entering tumors and killing the cancer cells inside—a finding that could pave the way toward new treatments for some aggressive forms of breast cancer. “During cancer progression, this molecule, known as DDR1, organizes a high-order extracellular matrix that acts like barbed wire around the boundary of a tumor to prevent immune cells from entering the tumor,” said Rong Li, the Ross Professor of Basic Science Research at GW and chair of the GW School of Medicine and Health Sciences Department of Biochemistry and Molecular Medicine. Dr. Li is the lead author of the paper published today in the journal “Nature.”
“Knowing that the DDR1 molecule creates a protective boundary around tumors, we were able to use pre-clinical models to show that the moment you deactivate DDR1, immune cells can infiltrate the tumor and kill the cells inside,” he said.
Dr. Li and his colleagues studied triple-negative breast cancer, an aggressive form of cancer that accounts for about 15% of all breast cancer cases. This type of cancer, according to the Centers for Disease Control and Prevention, lacks the receptors commonly used in targeted cancer therapies, making it difficult to target the tumor cells. Immunotherapy is designed to activate immune cells when they can get to the center of a tumor, but the DDR1 molecule puts up a physical barrier to anti-tumor immune cells.
Identifying the underlying mechanism could provide a new way of looking for novel therapeutic agents for this hard-to-treat cancer, Dr. Li said.