Resveratrol, a compound found commonly in grape skins and red
wine, has been shown to have several beneficial effects on human health,
including cardiovascular health and stroke prevention. Now, a University of
Missouri researcher has discovered that the compound can make prostate tumor
cells more susceptible to radiation treatment, increasing the chances of a full
recovery from all types of prostate cancer, including aggressive tumors.
"Other studies have noted that resveratrol made tumor cells
more susceptible to chemotherapy, and we wanted to see if it had the same
effect for radiation therapy," said Michael Nicholl, an assistant
professor of surgical oncology in the MU School of Medicine. "We found
that when exposed to the compound, the tumor cells were more susceptible to
radiation treatment, but that the effect was greater than just treating with
both compounds separately."
Prostate tumor cells contain very low levels of two proteins,
perforin and granzyme B, which can function together to kill cells. However,
both proteins need to be highly "expressed" to kill tumor cells. In
his study, when Nicholl introduced resveratrol into the prostate tumor cells,
the activity of the two proteins increased greatly. Following radiation
treatment, Nicholl found that up to 97 percent of the tumor cells died, which
is a much higher percentage than treatment with radiation alone.
"It is critical that both proteins, perforin and granzyme B,
are present in order to kill the tumor cells, and we found that the resveratrol
helped to increase their activity in prostate tumor cells," Nicholl said.
"Following the resveratrol-radiation treatment, we realized that we were
able to kill many more tumor cells when compared with treating the tumor with
radiation alone. It's important to note that this killed all types of prostate
tumor cells, including aggressive tumor cells."
Resveratrol is present in grape skins and red wine and available
over-the-counter in many health food sections at grocery stores. However, the
dosage needed to have an effect on tumor cells is so great that many people
would experience uncomfortable side effects.
"We don't need a large dose at the site of the tumor, but the
body processes this compound so efficiently that a person needs to ingest a lot
of resveratrol to make sure enough of it ends up at the tumor site. Because of
that challenge, we have to look at different delivery methods for this compound
to be effective," Nicholl said. "It's very attractive as a
therapeutic agent since it is a natural compound and something that most of us
have consumed in our lifetimes."
Nicholl said that the next step would be to test the procedure in
an animal model before any clinical trials can be initiated. Nicholl's studies
were published in the Journal of Andrologyand Cancer
Science. The early-stage results of this research are promising. If
additional studies, including animal studies, are successful within the next
few years, MU officials will request authority from the federal government to
begin human drug development (this is commonly referred to as the
"investigative new drug" status). After this status has been granted,
researchers may conduct human clinical trials with the hope of developing new
treatments for cancer.
Journal References:
1. Y. Fang, E. J. Herrick, M. B. Nicholl. A
Possible Role for Perforin and Granzyme B in Resveratrol-Enhanced
Radiosensitivity of Prostate Cancer. Journal of Andrology,
2011; 33 (4): 752 DOI:10.2164/jandrol.111.015164
2. Yujiang Fang, Vincent G. DeMarco, Michael B.
Nicholl.Resveratrol enhances radiation sensitivity in prostate cancer by
inhibiting cell proliferation and promoting cell senescence and apoptosis. Cancer
Science, 2012; 103 (6): 1090 DOI: 10.1111/j.1349-7006.2012.02272.x
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