Plant Compound May Help Fight Aggressive Breast Cancer
HER2-positive tumors are aggressive tumors that occur in about 25% of breast cancer cases. Some HER2-positive tumors do not respond to the therapies we currently have for the disease, so researchers are always evaluating new methods to cure this type of cancer. One promising compound may be found in the place I usually tell you to look – fruits and vegetables.
Psoralen is a natural component found in foods such as figs and celery. It helps fight certain types of cancer – including lymphoma – by disrupting DNA replication and causing cell death. Duke Medicine researchers have found that it may also have a second method of action that makes it particularly deadly against HER2-positive breast cancer tumors.
Reporting in the February 14 issue of the journal PLOS ONE, senior author Neil L. Spector MD writes that psoralen shuts down the process that allows uncontrolled cell growth. The compound appears to attack a form of HER2 present in the nucleus of the cells – something that current therapies such as lapatinib and trastuzumab have been unable to do.
“This was very unexpected,” said Dr. Spector, M.D. “Cancer drugs can recognize HER2 receptors when they are outside of the cell, but they don’t recognize the truncated version inside the cell nucleus.”
Unfortunately, the challenge will be to figure out a way of generating UV light deeper in the body. The benefits of Psoralen remain dependent upon its activation by an energy source. Dr. Spector and scientists from Immunolight (a company that funded this research) are working on a method for delivering tiny particles into the tumors which will then be targeted by a low-dose X-ray to activate the process. This technology is currently being tested in animals with human trials to begin later this year.
Psoralens are naturally occurring substances that belong to a group of compounds known as furocoumarins. Figs are on top of the list of foods that contain psoralen, but also some vegetables such as celery, celeriac, carrots, parsnips and root parsley are good natural sources. Certain spices and herbs – including anise, cumin, caraway, chervil, coriander, fennel, dill and mustard – are also good sources.
Xia W, Gooden D, Liu L, Zhao S, Soderblom EJ, et al. (2014) Photo-Activated Psoralen Binds the ErbB2 Catalytic Kinase Domain, Blocking ErbB2 Signaling and Triggering Tumor Cell Apoptosis. PLoS ONE 9(2): e88983. doi:10.1371/journal.pone.0088983
Susan G. Komen