CONTACT: DAVE PEDERSEN
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Iowa City IA 52242
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UI researchers study how maspin inhibits breast cancer cell movement
IOWA CITY, Iowa -- Researchers at the University of Iowa College of
Medicine are taking a lead role in understanding how a tumor suppressor
gene called maspin (mammary associated serine protease inhibitor) controls
breast cancer cell movement. Their findings could have a significant impact
on how breast cancer, and possibly other cancers, are diagnosed and treated.
Maspin occurs naturally in the cells of normal breast tissue and helps
maintain the normal state of the tissue. Its discovery was first reported
by researchers at the Dana Farber Cancer Institute and Harvard Medical
School in 1994, in collaboration with the laboratory of Dr. Mary J.C. Hendrix,
UI professor and head of anatomy and cell biology. The researchers found
that maspin slowed the growth and spread of breast tumors.
"Basically, when breast tissue cells lose maspin, they become cancerous,"
Hendrix says. "If a biopsy from a woman's breast sample contains
maspin, that's a good sign -- it's probably a benign tumor. However, a
biopsy that shows no maspin means that the cancer has more than likely
Early detection of breast cancer is crucial, Hendrix says, because evidence
suggests that often at the time of diagnosis, many patients may already
have metastases, the recurrent migration of tumor cells to other parts
of the body. "In other words, these cancerous cells may already be
on the move by the time they've been diagnosed," she says. "There
is a need to identify additional ways to determine the extent to which
the disease has progressed." One of the benefits of maspin is that
researchers can detect its presence or absence in tissues by using antibodies
to screen the biopsies of patients.
Understanding the biological mechanisms of maspin is the next step for
UI researchers. Hendrix and her colleagues have recently received a five-year,
$1.26 million grant from the National Institutes of Health to study how
maspin stops tumor cells from moving. One thought is that it inhibits
tumor cells from secreting certain proteases -- enzymes that are necessary
for cancer cells to digest their way through blood vessel basement membranes
in tissues. "It's good to know maspin keeps these cells from moving,
but it's equally important to know how this occurs," Hendrix says.
Knowing "how" could lead to possible cancer treatments. LXR
Biotechnology, Inc., a drug discovery and development firm based in Richmond,
Calif., has developed a recombinant form of maspin that could someday be
delivered to breast cancer patients who lack it. Biologically potent forms
of maspin are being studied under the direction of Dr. Philip Pemberton,
head of protein chemistry at LXR, who is collaborating with UI researchers.
"The overall goal is to stop the cancer cells in their tracks and
induce them to die," Hendrix says. "What we hope to learn from
this current study is that perhaps there is a certain stage of the cell
cycle where we would need to introduce maspin for it to be most effective."
Preliminary observations from Hendrix's laboratory indicate that maspin
may also be effective against prostate cancer, an area deserving additional
study, she says.
Much work still needs to be done, Hendrix notes, but the potential for
new cancer therapies being developed at the UI is solid. "This is
a very promising product. If all goes well, we'll be the first institution
to conduct clinical trials, in collaboration with LXR Biotechnology, perhaps
within the next year and a half."