Friday, November 7, 1997
Study finds cancer-suppressing cells in body
CANCER: Report says spread of disease can be stopped or confined
to certain ducts
By Kathryn Combs
Daily Bruin Staff
Cells already present in the body may be used to fight cancer,
UCLA researchers concluded in a study published on Nov. 3.
Laboratory experiments revealed that certain cells, which line
the ducts of the breast and prostate, have the ability to block the
spread of cancer beyond those duct systems – where cancer often
originates.
These cells, known as myoepithelial cells, are responsible for
mechanisms such as the secretion of milk in the breast and
ejaculatory fluid in the prostate gland.
Dr. Sheldon H. Brasky, a professor in the department of
pathology, explained that cancer almost always begins in the ducts
and rarely escapes, citing the fact that breast cancer can take
somewhere between four and 12 years to develop. Furthermore, during
this time the cancer can almost always be treated effectively.
Brasky, the primary researcher for this project, decided to
investigate the mechanism by which the cancer is suppressed.
"I’ve been convinced that (the myoepithelial cells) function
normally in the body by blocking the invasion and keeping cancers
of the breast and prostate confined to the ductile system," Brasky
said.
"Invasive cancer relies on the ducts within the secretory cells.
But they are confined to the duct for many years and the
myoepithelial cells limits this," he continued.
According to the study, the myoepithelial cells enclose the
cancerous cells and keep them inactive.
"The cells function as a defense against cancer," Brasky said,
explaining that cancer cells make enzymes to break through the
myoepithelial barrier.
However, when cancer cells break through the cellular border,
they spread, Brasky said.
Both the myoepithelial and cancer cells produce enzymes which
counter the effects of one another.
Brasky has been studying these cellular dynamics for almost
seven years.
The entire project was sponsored by the National Cancer
Institute and the Carolan Foundation.
Brasky stresses, however, that the first five years were spent
learning how to effectively culture the myoepithelial cells in the
lab.
Mary Alpaugh, a post-doctoral student who works with Brasky, now
continues this research.
"I will start working on the identification of the proteins that
these myoepithelial cells secrete," Alpaugh said.
"We can look more closely at what allows the myoepithelial cells
to suppress tumors," she said.
In addition, researchers also found that myoepithelial cells
affect angiogenesis, which is a consequence of cancer causing the
blood vessels to expand and nourish the disease.
"Cancer cells stimulate the growth of blood vessels that nourish
the cancer and they grow larger," Brasky said.
"Our (cultures) do not make any angiogenic factors, in fact they
make angiogenic inhibitors. They are opposing what the cancer is
trying to do," Brasky said.
Blocking the invasion of cancerous cells to the rest of the body
is important to many, Brasky said.
"We hope to learn more about what molecules are being made by
the myoepithelial cells that block invasion and deliver them to the
patients that have cancer," Brasky said.
Presently, the research is still in its laboratory stage, Brasky
said.
"(However), no one has ever made this observation and keep in
mind that you are saying that these cells do this in patients
already."
Zhi-Ming Chou, a post-doctoral student who also works with
Brasky, stressed the importance of research.
"Laboratory research is what clinical practices are based on.
You need to collect data. If you don’t have research, you don’t
have anything," Chou said.
HANNAH SADY
Dr. Sheldon H. Brasky has been studying myoepithelial cells and
cancer cells for nearly seven years.