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A
radical approach to cancer
Das U
EFA Sciences LLC, Norwood, MA 02062, USA.
undurti@hotmail.com
Reactive oxygen species are known to be potentially dangerous, but are
also needed for signal-transduction pathways.
Tumor cells have relatively low amounts of superoxide dismutase (SOD), which
quenches superoxide anion (O2(-*)), and as a result of a higher level of aerobic
metabolism, higher concentrations of O2(-*) , compared to normal cells.
But this may not be true of all tumor cells.
Some tumor cells have relatively higher amounts of vitamin E, a potent
anti-oxidant, and a higher level of anaerobic metabolism, resulting in a balance
that is tilted more towards higher anti-oxidant capacity.
In both instances of higher aerobic and anaerobic metabolism methods designed to
augment free radical generation in tumor cells can cause their death.
It is suggested that free radicals and lipid peroxides suppress the expression
of Bcl-2, activate caspases and shorten telomere, and thus inducing apoptosis of
tumor cells.
Ionizing radiation, anthracyclines, bleomycin and cytokines produce free
radicals and thus are useful as anti-cancer agents.
But they also produce many side-effects. 2-methoxyoestradiol and polyunsaturated
fatty acids (PUFAs) inhibit SODs and cause an increase of O2(-*) in tumor cells
leading to their death.
In addition, PUFAs (especially gamma-linolenic acid), 2-methoxyoestradiol and
thalidomide may possess anti-angiogenic activity.
This suggests that free radicals can suppress angiogenesis.
Limited clinical studies done with gamma-linolenic acid showed that it can
regress human brain gliomas without any significant side-effects.
Thus, PUFAs, thalidomide and 2-methoxyoestradiol or their derivatives may offer
a new radical approach to the treatment of cancer.
PMID:
11951081 [PubMed - indexed for MEDLINE]
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