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NEWS: Sept 1, 2007 from NIH:
Unique Grape Skin Extract Inhibits
Prostate Cancer Cell Growth in the Laboratory
Laboratory experiments show that an extract of the skin of muscadine
grapes can inhibit growth of prostate cancer cells in the laboratory.
Investigators from the National Cancer Institute (NCI), part of the National
Institutes of Health, and their research partners also show that muscadine
grape skin extract (MSKE) does not contain significant amounts of
resveratrol, another grape skin component that has been widely studied and
shown to be of potential benefit in preventing prostate cancer growth. The
results appear in the September 1, 2007, issue of Cancer Research.
Using a series of human prostate cancer cells, representing different
stages of prostate cancer progression, the researchers showed that MSKE
significantly inhibits the growth of cancerous, but not normal, prostate
cells, primarily by inducing a process called apoptosis, or programmed cell
death. Programmed cell death is one of the mechanisms the body uses to rid
itself of cells with unrepaired genetic damage before those cells can
duplicate themselves. In contrast, resveratrol seems to act by blocking the
cell cycle, a sequence of steps that a cell passes through when it grows and
divides into two identical cells. Both mechanisms are used by the body to
prevent the development of cancer.
According to Jeffrey E. Green, M.D., chief of the Transgenic Oncogenesis
and Genomics Section in NCI's Center for Cancer Research (CCR), "These
results show that MSKE may have potent antitumor activities in the lab that
differ from the effects of resveratrol. Further studies of MSKE will be
necessary to determine if this extract has potential as a chemopreventive or
therapeutic agent."
The fact that all of the cells studied, which cover the different stages
of prostate cancer tumor progression, responded to MSKE suggests that the
active compounds in this extract may inhibit tumor development at very early
stages.
The muscadine grape (Vitis rotundifolia) is distinct from the
more common red grapes used to produce red wines, a major source of
resveratrol. The chemical constituents of muscadine grapes differ from most
other grape varieties, as they are richer in chemicals called anthocyanins.
Anthocyanins, which produce the red and purple colors of the grapes, have
strong antioxidant activity and have shown several antitumor effects,
including inhibition of DNA synthesis in breast cancer cells, of blood
vessel growth in some tumors, and of enzymes involved in tumor spread.
Muscadine grapes can be found growing wild from Delaware to the Gulf of
Mexico and westward from Missouri to Texas.
While previous studies suggested that anthocyanins might suppress the
cancer process, no rigorous study of the mechanisms underlying these effects
has yet been done. Resveratrol, by contrast, has been widely examined.
Although earlier studies showed that it can induce programmed cell death in
prostate cancer cells, resveratrol did not significantly induce cell death
in the prostate cell model system used for this muscadine study. The results
of this study suggest that resveratrol may activate different antitumor
mechanisms than MSKE.
Even though MSKE had significant inhibitory effects on the prostate
cancer cells studied, it did not alter the growth rate of the normal human
prostate cells in the lab, which served as controls. Ongoing studies of MSKE
in animals will help to determine the underlying mechanisms of MSKE's
inhibitory effects in prostate cancer cells. The researchers hope that the
lab effects of MSKE will be reproducible in testing on cancerous and normal
prostate cells in animals. Should MSKE move on to trials in humans, Green
says that since "muscadine grape products, including grape juice and grape
wine, have been used in human studies without reported side effects, they
may be relatively safe for use in clinical trials."
For more information about cancer, please visit the NCI website at
www.cancer.gov, or call NCI's Cancer Information Service at 1-800-4
CANCER (1-800-422-6237).
For more information on Dr. Green's research at NCI, please go to
http://ccr.cancer.gov/staff/staff.asp?profileid=5721.
The National
Institutes of Health (NIH) — The Nation's Medical Research Agency —
includes 27 Institutes and Centers and is a component of the U.S. Department
of Health and Human Services. It is the primary federal agency for
conducting and supporting basic, clinical and translational medical
research, and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and its programs,
visit
www.nih.gov.
Articles, papers, arguments & opinions, thoughts, all welcome.
Email to: admin@resveratrolnews.com
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