Arsenic triggers flood of free radicals
2001-02-26 12:12
New York - Arsenic's cancer-causing
properties may stem from the production of DNA-damaging
particles called free radicals, researchers report. The finding
supports the use of antioxidants such as vitamin C and vitamin
E, which mop up free radicals, in cancer prevention.
ôHaving a better understanding of how arsenic causes gene
mutations and cancers provides a means to design interventions
both in the treatment as well as in the prevention (of
cancer),ö Dr Tom Hei from Columbia University in New York told
Reuters Health.
Hei and associates studied the effects of arsenic on cells
grown in the laboratory. They report their results in the
February 13th issue of the journal Proceedings of the National
Academy of Sciences.
Cells exposed to arsenic produced about three times as many
damaging free radicals as other cells, the authors report, and
an antioxidant cut the level of free radicals in the
arsenic-exposed cells by half.
Arsenic exposure also doubled the number of cells with
genetic mutations, the researchers note. And when an
antioxidant blocker was added to the mix, mutated cells
increased by 5 to 16 times.
Studies have already shown arsenic to be a human
carcinogen, but before this study, the way arsenic caused
cancer was unclear, the report indicates.
These results, however, clearly demonstrate that the
generation of free radicals within minutes of arsenic exposure
can lead to gene mutations and death of the cell, the authors
conclude, and that antioxidants can block those effects.
ôArsenic is an important environmental contaminant, being
number 1 in the EPA (environmental protection agency) Superfund
list,ö Hei explained. ôThe degree of human sufferings caused by
arsenic is beyond comprehension in some other parts of the
world, such as in Bangladesh and West Bengal, India where an
estimated 50 million people are at risk from drinking arsenic
contaminated water.ö