Breast cancer cells can lay the groundwork for their own spread throughout the body by coaxing cells within lymphatic vessels to send out tumor-welcoming signals, according to a new report by Johns Hopkins scientists.
Writing in the Sept. 2 issue of Nature Communications, the researchers describe animal and cell-culture experiments that show increased levels of so-called signaling molecules released by breast cancer cells. These molecules cause lymphatic endothelial cells (LECs) in the lungs and lymph nodes to produce proteins called CCL5 and VEGF. CCL5 attracts tumor cells to the lungs and lymph nodes, and VEGF increases the number of blood vessels and makes them more porous, allowing tumor cells to metastasize and infiltrate the lungs.
In the same report, the researchers say maraviroc, a drug already approved for treating HIV infection, blocked the siren call of CCL5 in tests on animals and cells and prevented tumor spread (metastasis). Additional experiments using a combination of maraviroc and a drug that blocks the VEGF protein suggest that the treatment duo could be an effective way to prevent metastatic disease in human breast cancer patients, according to the researchers.
Because the anti-retroviral drug maraviroc has already been approved by the U.S. Food and Drug Administration and has been shown safe for long term, oral use, it could be tested in clinical trials sooner rather than later, says Aleksander Popel, Ph.D., a professor in the Department of Biomedical Engineering at the Johns Hopkins University School of Medicine and member of the Johns Hopkins Kimmel Cancer Center.
"It was surprising to find that LECs can play such an active and significant role in tumor spread." Popel noted. "Conventionally, lymphatic vessels are regarded mainly as passive conduits through which tumor cells spread from the primary tumor and eventually metastasize," he said. "However, we now know that lymphatic vessels enabl
|Contact: Vanessa Wasta|
Johns Hopkins Medicine