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Anti-cancer compound found to block
late-stage breast-cancer cell growth
McElroy, News Bureau
photo to enlarge
by Kwame Ross
Singletary, above, and doctoral student Steven Jackson report
their finding involving sulforaphane (SUL), which they say
could ultimately be used to enhance the prevention and treatment
of breast cancer, in the September issue of the Journal of
Ill. — A well known anti-cancer agent in certain vegetables has
just had its reputation enhanced. The compound, in broccoli and other
cruciferous vegetables, has been found to be effective in disrupting
late stages of cell growth in breast cancer.
Keith Singletary and doctoral student Steven Jackson of the University
of Illinois at Urbana-Champaign report their finding involving sulforaphane
(SUL), which they say could ultimately be used to enhance the prevention
and treatment of breast cancer, in the September issue of the Journal
“This is the first report to show how the naturally occurring
plant chemical sulforaphane can block late stages of the cancer process
by disrupting components of the cell called microtubules,” said
Singletary, a professor in the department of food
science and human nutrition. “We were surprised and pleased
to find that SUL could block the growth of breast cells that were already
SUL is abundant in such vegetables as broccoli, brussels sprouts and
kale. Chewing causes the cell walls of these vegetables to break, and
SUL is released into the body.
Singletary, a researcher in phytochemicals and cancer chemoprevention,
and Jackson exposed cultures of malignant human breast cancer cells
to SUL. Within hours, SUL blocked cell division and disrupted microtubules,
which are long, slender cylinders made up of tubulin (protein), that
are essential for the separation of duplicated chromosomes during cell
“It is not yet clear whether the doses required to produce inhibition
of tubulin polymerization are higher than those achievable via dietary
intakes,” wrote Jackson and Singletary. “However, the results
show that tubulin disruption may be an important explanation for SUL’s
“These findings are significant since SUL’s actions appear
similar to a group of anticancer drugs currently in use, such as Taxol,”
SUL is studied extensively for its effects against cancer. Previous
reports have shown that SUL induces defensive mechanisms that are effective
in protecting normal cells from the initiation of cancer.
“More than 10 years ago, researchers at Johns Hopkins University
reported that SUL is a potent inducer of enzyme systems that can defend
against carcinogens,” Singletary said. Such defense mechanisms
are effective during the early stage of cancer.
The Illinois research extends the 1992 discovery at Johns Hopkins and
pinpoints how SUL works during later stages of cancer, such that SUL
can suppress the orderly division process in human breast cancer cells.
“The findings may be helpful in the development of new breast
cancer prevention and treatment strategies,” Singletary said.
“For example, it may be possible that ingesting SUL in combination
with certain natural compounds or drugs could enhance their anticancer
effectiveness and reduce side effects.”
According to the American Cancer Society, breast cancer this year will
account for 15 percent of all cancer deaths in women, and approximately
275,000 new breast cancer cases of various forms will be diagnosed.
Improvements in treatments such as chemotherapy have led to an 88 percent
survival rate in Caucasian women and a 74 percent survival rate in African-American
women, according to the most recent ACS survey in 2003.
However, some current chemotherapy drugs have side effects that have
the ACS and other organizations seeking new strategies that combine
chemotherapy drugs with other treatments to potentially lessen the toxic
The new Illinois study confirms a previous study in mice. In the February
2004 issue of the journal Carcinogenesis, Singletary and Jackson reported
that SUL treatments in mice with implanted cancer cells resulted in
decreased tumor size.
More research is needed to assess SUL’s potential in countering
breast cancer development, Singletary said. “What we do not know
is how specific SUL and other similar phytochemicals are toward cancer
cells compared to normal cells,” he said. “We also do not
know against which cancers SUL’s microtubule-targeting actions
are most effective.”
Future studies in Singletary’s lab will address those issues.
The University of Illinois Agricultural Experiment Station and the U.S.
Department of Agriculture funded the research.