MAY 4, 1998
Researchers Discover Cancer Invasion Enzymes In Killer Cells
FORT WORTH, Texas-- A mystery related to how the immune response helps protect
against cancer has reached a new level of understanding through research reported
from the University of North Texas Health Science Center. The research reveals
the presence of two enzymes in a type of white blood cell that are usually found
in advanced tumors. The research is published in the May 1 edition of the
Journal of Immunology.
Led by Dr. Ronald H. Goldfarb, chairman of the department of molecular biology
and immunology at the UNT Health Science Center, this research is the first to
show that certain destructive enzymes are produced by white blood cells called
activated natural killer cells. These enzymes, known as matrix
metalloproteinases (MMPs), are widely known for a very negative role: helping
tumor cells spread throughout the body. It now appears that these enzymes might
also help cancer-killing white blood cells search out and destroy aggressive
tumors.
Natural killer cells recognize and kill tumor cells as the first line of defense
of the immune response against cancer. While natural killer cells have the
ability to kill tumor cells, they have to first accumulate within the tumor in
order to be effective. ThatÕs where the work reported by the Fort Worth-based
researchers comes into play. When natural killer cells are stimulated with a
protein called interleukin-2, they become activated natural killer cells which
have a more lethal effect against cancer cells. They also hunt down malignant
tumors with greater speed and certainty. According to Dr. Goldfarb, within 16
hours of the injection, activated natural killer cells are able to migrate out of
blood vessels in the tumor and attach to tumor cells where the have a better
chance to help destroy the tumor.
ÒWe noted that activated natural killer cells seemed to travel throughout the
body like the tumor cells they were trying to kill Ñ that is, they also travel
throughout the body and track the tumor cells that spread throughout the body,Ó
said Dr. Goldfarb. ÒThe destructive enzymes of the killer cells may help in this
tracking and help lead to the ultimate devastation of the advanced tumors that
they invade.Ó
As reported in this monthÕs Journal of Immunology , the health science centerÕs
research has implications for the possible develpment of new drug therapies for
advanced cancer.
Dr. GoldfarbÕs six-year research program, which began at the University of
Pittsburgh Cancer Institute, was initially funded by the National Cancer
Institute/National Institutes of Health. The American Cancer Society later funded
the research grant, the only American Cancer Society research grant in Tarrant
County. Dr. Goldfarb plans to establish an Institute for Cancer Research at the
health science center in the coming months.
Other investigators in this research include Dr. Richard P. Kitson of the health
science center, Dr. Pierette M. Appasamy, University of Pittsburgh School of
Medicine; Dr. Ulf Nannmark, University of Gšteborg, Sweden; Dr. Per Albertsson,
visiting scientist at the health science center also from the University of
Gšteborg; and Megan K. Gabauer, formerly of the University of Pittsburgh Cancer
Institute.