University of Hawaii
finds link in stopping tumor growth
In a major discovery, chemicals that
give vegetables their color show cancer-fighting properties
By Helen Altonn
haltonn@starbulletin.com
Pigments that give yellow, red and green vegetables their
colors stop tumors from growing and can prevent cancer by
keeping cells "talking" to each other, University
of Hawaii cancer researchers have discovered.
People who eat large amounts of these vegetables tend to
have a lower risk of cancer and heart and eye diseases,
said Dr. John Bertram, professor of cell and molecular biology
at the John A. Burns School of Medicine and Cancer Research
Center.
Reporting on his group's research yesterday at the BioScience
2004 conference in Glasgow, Scotland, Bertram said the study
found the pigments, called carotenoids, increased activity
of a molecule called connexin 43.
The molecule forms small channels between cells and connects
nearly all cells in the body, he said. Cells exchange nutrients
through the channels and many signals responsible for normal
cellular growth.
But most tumor cells have lost the ability to communicate
and become isolated from normal cells, according to reports
on his work by BioScience, BBC News and NUTRAIngredients.com.
Treating normal mouse cells with carotenoids improved communication
in the cells and prevented cancer-causing chemicals from
forming cancer, Bertram said.
Communication between cells also was restored when three
types of human tumors were treated with carotenoids. The
cells behaved more normally in cultures and when grown in
laboratory animals, he said.
Marc Goodman, Cancer Research Center of Hawaii researcher,
said that "one of the hallmarks of cancer is unregulated
growth," when cancer cells are no longer getting appropriate
signals to stop growing.
He said Bertram has shown chemicals such as carotenoids
help to regulate growth by ensuring there is communication
between cells. As a result, he said, there is "tremendous
potential" for types of carotenoids not only to prevent
cancer, but to augment cancer therapy.
Bertram advises eating carotenoid-rich vegetables and fruits
and is collaborating with Hawaii Biotech Inc. to develop
easily absorbed carotenoid tablets for use to prevent cancer,
liver and eye disease and damage to the heart.
David Watumull, president and chief executive officer of
the biopharmaceutical company in Aiea, said data on three
species of animals shows new carotenoids being developed
can prevent proliferation of cancer cells and prevent damage
during or after cardiovascular procedures such as angioplasty.
Bertram said in Glasgow that the researchers looked at five
or six carotenoids, and they all appear able to restore
communication between cells.
He also found that activity of connexin 43 molecules could
be increased by retinoids, another cancer preventive agent
derived from vitamin A, especially when combined with carotenoids.
"This is a new mechanism whereby tumor growth can be
interrupted," he reported. "Connexin 43 may be
a potential new target for cancer treatment."
He said carotenoids and retinoids might stop cancers from
forming by keeping cells communicating. "Prevention
is always better than the cure, and prevention of cancer
should be a priority goal for health care professionals."
Studies were presented to the conference showing up to 70
percent of human cancer is preventable and 40 percent could
be associated with diet.
Carotenoid tablets are available, but they do not dissolve
well in water and are not easily absorbed in the body, Bertram
said.
The new versions he has developed with Hawaii Biotech are
water-dispersible and up to 100 times more effective in
cell cultures, mostly because of better absorption, he said.
Rapid and more complete absorption of carotenoids taken
by mouth "could offer a significant advantage in future
cancer prevention studies," he said.
Watumull said Hawaii Biotech is in preclinical stages of
development, looking at manufacturing new compounds according
to U.S. Food and Drug Administration standards. Human clinical
trials on the new tablets will be done in about a year,
he said.
"You will absorb our compounds better and have the
right kind for the disease you are at risk for, because
different ones (carotenoids) accumulate in different tissues."
he said. "There may be one best for cardiovascular
disease and a different one for prostate cancer."
Cancer Research Center of Hawaii
www.crch.org
UH John A. Burns School of Medicine
hawaiimed.hawaii.edu
BioScience 2004
www.bioscience2004.org