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June, Lillian, found it in Sloan-Kettering website.
The journalists wrote the headline which is actually not correct. THe
report does not say that the cancer cells consume or do anything with
the vitamin C. The key word is ACQUIRE. Does not say REQUIRE.... yet!
More research needed on this one. What does the cancer cells DO with the
Vitamin C when they acquire it? Does having large amounts of vitamin C
in the cancer cells slow or accelerate the growth of the cancer cells?
This study was not meant to determine this point. Off to bed. 11:00 pm
here on the Pacific North West, rain and wind, what else? Jeanne
http://www.mskcc.org/patients_n_public/info_for__/journalists/press_releases/cancer_tumors_shown_to_consume_large_amounts_of_vitamin_c_body.html
Cancer Tumors Shown
to Consume Large
Amounts of Vitamin C
New York, September 15 – Researchers at
Memorial Sloan-Kettering Cancer Center
have found that cancer tumors consume
large amounts of vitamin C. Their findings,
which are reported in the September 15
issue of Cancer Research, may shed new
light on the nutritional needs of tumors.
"This study is the first to demonstrate
exactly how cancer cells acquire large
quantities of vitamin C," said Dr. David
Golde, senior author of the study and
Physician-in-Chief of Memorial Hospital.
Although the role that vitamin C plays in
tumors is not yet known, recent studies have
shown that there may be possible
interactions between dietary antioxidants
and chemotherapy treatment. Vitamin C is a
powerful antioxidant that consumes free
radicals – or toxic substances in the body
that can also be generated from
chemotherapy agents to destroy cancer
cells.
"It’s possible that taking large amounts of
vitamin C could interfere with the effects of
chemotherapy or even radiation therapy,
since these therapies often kill cells in part
by using oxidative mechanisms. It’s
conceivable then, that vitamin C might make
cancer treatment less effective and
therefore, reasonable that cancer patients
undergoing chemotherapy should avoid
taking large amounts of this vitamin," said
Dr. Golde.
Earlier research by Dr. Golde and his
colleagues had established that specific
glucose transporter molecules were
responsible for transporting vitamin C into
cells. This process occurs when vitamin C,
which is used by cells in the form of
ascorbic acid, is converted into the form of
dehydroascorbic acid and transported into
the cell. Once inside, the vitamin is
converted back to ascorbic acid.
This discovery prompted Dr. Golde’s team
to explore whether glucose transporter
molecules and vitamin C might function in
cancer cells, as malignant cells devour
more glucose than normal cells to obtain the
energy they need to grow. Subsequently,
their laboratory studies with myeloid
leukemia cells showed that the cells
accumulated high levels of vitamin C
through their glucose transporters.
Building on this research, the researchers
hypothesized that human leukemia, breast
and prostate cancer cells would acquire
large amounts of vitamin C in the same way.
To find out, mice were injected with human
cancer cells of the breast, prostate and
blood and, after tumors had developed,
were injected with ascorbic acid,
dehydroascorbic acid, or sucrose (as a
measure of blood volume). All tumors were
subsequently analyzed for vitamin C
content. The researchers found that the
tumors readily took up vitamin C by a
process involving the conversion of
ascorbic acid to dehydroascorbic acid.
"Now we know that tumors acquire and
retain large amounts of vitamin C. So, it
appears that tumors have nutritional needs,
similar to other healthy cells that take in
large amounts of the vitamin," said Dr.
David Agus, first author of the study and an
oncologist at Memorial Sloan-Kettering
Cancer Center. "More studies need to be
done to determine what the tumor cells do
with the vitamin C once they get it."
Memorial Sloan-Kettering Cancer Center is
the world’s oldest and largest private
institution devoted to prevention, patient
care, research, and education in cancer.
Throughout its long distinguished history,
the Center has played a leadership role in
defining the standard of care for patients
with cancer. In 1999, Memorial
Sloan-Kettering was named the nation’s
best cancer care center for the seventh
consecutive year by U.S. News & World
Report.
Contact:
Joanne Nicholas
(212) 639-3632
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Title: Cancer Tumors Shown to Consume Large Amounts of Vitamin C
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Cancer Tumors Shown to Consume Large Amounts of Vitamin C
"This study is the first to demonstrate exactly how cancer cells acquire large quantities of vitamin C," said Dr. David Golde, senior author of the study and Physician-in-Chief of Memorial Hospital. Although the role that vitamin C plays in tumors is not yet known, recent studies have shown that there may be possible interactions between dietary antioxidants and chemotherapy treatment. Vitamin C is a powerful antioxidant that consumes free radicals – or toxic substances in the body that can also be generated from chemotherapy agents to destroy cancer cells. "It’s possible that taking large amounts of vitamin C could interfere with the effects of chemotherapy or even radiation therapy, since these therapies often kill cells in part by using oxidative mechanisms. It’s conceivable then, that vitamin C might make cancer treatment less effective and therefore, reasonable that cancer patients undergoing chemotherapy should avoid taking large amounts of this vitamin," said Dr. Golde. Earlier research by Dr. Golde and his colleagues had established that specific glucose transporter molecules were responsible for transporting vitamin C into cells. This process occurs when vitamin C, which is used by cells in the form of ascorbic acid, is converted into the form of dehydroascorbic acid and transported into the cell. Once inside, the vitamin is converted back to ascorbic acid. This discovery prompted Dr. Golde’s team to explore whether glucose transporter molecules and vitamin C might function in cancer cells, as malignant cells devour more glucose than normal cells to obtain the energy they need to grow. Subsequently, their laboratory studies with myeloid leukemia cells showed that the cells accumulated high levels of vitamin C through their glucose transporters. Building on this research, the researchers hypothesized that human leukemia, breast and prostate cancer cells would acquire large amounts of vitamin C in the same way. To find out, mice were injected with human cancer cells of the breast, prostate and blood and, after tumors had developed, were injected with ascorbic acid, dehydroascorbic acid, or sucrose (as a measure of blood volume). All tumors were subsequently analyzed for vitamin C content. The researchers found that the tumors readily took up vitamin C by a process involving the conversion of ascorbic acid to dehydroascorbic acid. "Now we know that tumors acquire and retain large amounts of vitamin C. So, it appears that tumors have nutritional needs, similar to other healthy cells that take in large amounts of the vitamin," said Dr. David Agus, first author of the study and an oncologist at Memorial Sloan-Kettering Cancer Center. "More studies need to be done to determine what the tumor cells do with the vitamin C once they get it." Memorial Sloan-Kettering Cancer Center is the world’s oldest and largest private institution devoted to prevention, patient care, research, and education in cancer. Throughout its long distinguished history, the Center has played a leadership role in defining the standard of care for patients with cancer. In 1999, Memorial Sloan-Kettering was named the nation’s best cancer care center for the seventh consecutive year by U.S. News & World Report. Contact: |
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