New Findings on the Role of Glutathione in Cancer
Copyright © 2004
Priya Shah
Cancer cells and normal cells are known to respond differently to
nutrients and drugs that affect glutathione status.
Numerous studies have shown that tumor cells have elevated levels of
glutathione levels, which confers resistance to chemotherapy drugs.
One of the challenges of cancer therapy is how to deplete tumor cells
of glutathione, so as to make them more vulnerable to the effects of
chemotherapy drugs, while at the same time allowing normal cells to
remain relatively unaffected by chemotherapeutic drugs.
A number of new findings have emerged that take into consideration the
role of glutathione in pathways that promote programmed cell death
(apoptosis) in cancer cells.
A German study has reported that glutathione (GSH) plays a critical
role in cellular mechanisms that result in cell death. The study found
that cancer cells resistant to apoptosis had higher intracellular GSH
levels.
Depletion of glutathione in these tumor cells made them more vulnerable
to the effects of anticancer drugs or the gene that promotes apoptosis
(CD95 or APO-1/Fas). The researchers concluded that apoptosis
resistance in tumor cells depends, at least in part, on intracellular
GSH levels. (1)
In another study conducted in Spain, researchers found that lowering
GSH concentration may be convenient not only for the efficiency of
chemotherapy, but also to induce a rather fast and direct apoptosis
mechanism in tumor cells. (2)
Based on that premise that the glutathione-S-transferase enzyme is
expressed at high levels in many tumors, researchers at the Fox Chase
Cancer Center in Pennsylvania, went on to design a novel prodrug
(PABA/NO).
The glutathione-s-transferase in tumor cells converts PABA/NO to lethal
nitric oxide, resulting in death of the tumor cell. The prodrug was
shown to have antitumor effects in an animal model for human ovarian
cancer. (3)
In the fourth study, Polish researchers found that ingesting a selenium
supplement is beneficial, as a supportive element in chemotherapy. (4)
Selenium is a co-factor of the enzyme glutathione peroxidase [GSH-P(x)]
and was found to significantly increase the activity of GSH-P(x) in
patients reciving the supplement.
A previous clinical study by the same researchers recommended the
administration of selenium in patients with ovarian cancer undergoing
multi-drug chemotherapy. (5)
Another interesting study by researchers in Texas showed that your
chances of surviving a type of brain cancer, called primary malignant
glioma, could depend on the type of glutathione-s-transferase (GST)
gene you were born with.
Having a combination of a two specific variants of GST (germ-line
GSTP1*A/*A and GSTM1 null genotype) confers a survival advantage in
some types of brain cancers, but also comes with an increased risk of
adverse events related to chemotherapy. (6)
There is compelling evidence to suggest a crucial role for glutathione
and substances that target glutathione metabolism in the prevention and
treatment of cancer.
Undenatured whey protein is one of the natural foods known to
selectively deplete cancer cells of their glutathione, thus making them
more susceptible to such cancer treatments as radiation and
chemotherapy.
For a complete report on the research on undenatured whey protein and
cancer see the report Glutathione (GSH) and Whey Protein in
Cancer.
http://www.1whey2health.com/cancer_glutathione.htm
Disclaimer: The information here is not provided by medical
professionals and is not intended as a substitute for medical advice.
Please consult your physician before beginning any course of treatment.
References:
1. Friesen C et al. [Cell Death and Differentiation advance online
publication, 23 April 2004]
2. Tormos C et al. [Cancer Lett. 2004 May 10;208(1):103-13.]
3. Findlay VJ et al. [Mol Pharmacol. 2004 May;65(5):1070-9.]
4. Sieja K et al. [Gynecol Oncol. 2004 May;93(2):320-327.]
5. Sieja K. [Pharmazie. 1998 Jul;53(7):473-6.]
6. Okcu MF et. al. [Clin Cancer Res. 2004 Apr 15;10(8):2618-25.]
This article was first published in the April 2004 issue of The
Glutathione
Report,
http://www.glutathione-report.com
, a newsletter featuring regular updates on the health benefits of
glutathione.
Get a Free report on Glutathione in Health and Disease
http://www.1whey2health.com
For a complete report on the research on undenatured whey protein and
cancer
see the report
http://www.1whey2health.com/cancer_glutathione.htm