|
Bacteria has been
used in the treatment of cancer for a hundred years because
of its ability to shrink tumors. However, the bacteria often
yields severe side effects, which limits its practical usage.
In a new study
conducted by University of Illinois at Chicago (UIC) researchers,
azurin, a protein secreted by bacteria, was found to kill
cancer cells with seemingly no harmful side effects. The protein,
used by cells everyday in generating energy, was isolated
from the growth medium of a particularly resistant bacterium
known as Pseudomonas aeruginosa. This bacteria is usually
unaffected by antibiotics and can cause infections in people
with lowered resistance.
The bacteria was
tested on mice that had been injected with human melanomas.
At the end of the 22-day study, the tumors in the mice that
had been treated with azurin were 60 percent smaller than
the tumors in the untreated mice. Additionally, no illness
or deaths were seen in the mice.
According to researchers,
azurin stabilizes the p53 protein, a product of the p53 gene.
This gene prevents the formation of cancers by stopping cells
from dividing or inducing programmed cell death, or apoptosis,
of cancer cells. While the p53 protein normally only survives
for several minutes within a cell, azurin protects the protein
from degradation.
Results suggest
that azurin could be a useful in treating both melanomas and
tumors; preliminary data have shown that it kills breast and
colon cancer cells, among others.
Physician William
Coley first observed the usefulness of bacteria in treating
cancers in 1893 when he found that patients with bone cancer
survived longer when they contracted bacterial infections.
Proceedings
National Academy Sciences Oct 29, 2002;99(22):14098-103
| 