Shotgun Approach with Black Raspberry Agents Does
Best Job of Slowing Cancer
Black raspberries have vitamins, minerals, phenols
and phytosterols, many of which prevent cancer in animals
Aug. 27, 2008 – A shotgun approach may be more
effective than a rifle’s pin point accuracy, when it comes to stopping
cancer growth. New research has found that a mix of preventative agents,
such as those found in concentrated black raspberries, more effectively
inhibit cancer development than single agents aimed at shutting down one
particular gene.
Researchers at the
Ohio State University Comprehensive Cancer Center examined the
effect of freeze-dried black raspberries on genes altered by a chemical
carcinogen in an animal model of esophageal cancer.
The carcinogen affected the activity of some 2,200
genes in the animals’ esophagus in only one week, but 460 of those genes
were restored to normal activity in animals that consumed freeze-dried
black raspberry powder as part of their diet during the exposure.
These findings, published in recent issue of the
journal
Cancer Research, also helped identify 53 genes that may play a
fundamental role in early cancer development and may therefore be
important targets for chemoprevention agents.
“We have clearly shown that berries, which contain
a variety of anticancer compounds, have a genome-wide effect on the
expression of genes involved in cancer development,” says principal
investigator
Gary D. Stoner, a professor of
pathology,
human nutrition and
medicine who studies dietary agents for the prevention of esophageal
cancer.
“This suggests to us that a mixture of preventative
agents, which berries provide, may more effectively prevent cancer than
a single agent that targets only one or a few genes.”
Stoner notes that black raspberries have vitamins,
minerals,
phenols and
phytosterols, many of which individually are known to prevent cancer
in animals.
“Freeze drying the berries concentrates these
elements about ten times, giving us a power pack of chemoprevention
agents that can influence the different signaling pathways that are
deregulated in cancer,” he says.
“What’s emerging from
studies in cancer chemoprevention is that using single compounds
alone is not enough.
And berries are not
enough.
We never get 100
percent tumor inhibition with berries, so we need to think about
another food that we can add."
To conduct this study, Stoner and his colleagues
fed rats either a normal diet or a diet containing 5 percent
black-raspberry powder. During the third week, half the animals in each
diet group were injected three times with a chemical carcinogen, N-nitrosomethylbenzylamine.
The animals continued consuming the diets during the week of carcinogen
treatment.
After the third week, the researchers examined the
animals’ esophageal tissue, thereby capturing gene changes that occur
early during carcinogen exposure. Their analyses included measuring the
activity, or expression levels, of 41,000 genes.
In the
carcinogen-treated animals, 2,261 of these genes showed changes in
activity of 50 percent or higher.
“These changes in gene expression correlated with
changes in the tissue that included greater cell proliferation, marked
inflammation, and increased apoptosis,” Stoner says.
In the animals fed berry powder, however, a fifth
of the carcinogen affected genes – exactly 462 of them – showed
near-normal levels of activity, when compared with controls. Most of
these genes are associated with cell proliferation and death, cell
attachment and movement, the growth of new blood vessels and other
processes that contribute to cancer development.
The tissue also
appeared more normal and healthy.
Lastly, of the 462 genes restored to normal by the
berries, 53 of them were also returned to normal by a second
chemoprevention agent tested during a companion study.
“Because both berries and the second agent maintain
near-normal levels of expression of these 53 genes, we believe their
early deregulation may be especially important in the development of
esophageal cancer,” Stoner says.
“What’s emerging from studies in cancer
chemoprevention is that using single compounds alone is not enough,”
Stoner says. “And berries are not enough. We never get 100 percent tumor
inhibition with berries. So we need to think about another food that we
can add to them that will boost the chemopreventive activities of
berries alone.”
Aug. 27, 2008 – A shotgun approach may be more
effective than a rifle’s pin point accuracy, when it comes to stopping
cancer growth. New research has found that a mix of preventative agents,
such as those found in concentrated black raspberries, more effectively
inhibit cancer development than single agents aimed at shutting down one
particular gene.