WASHINGTON: In what's being claimed as
a major breakthrough, scientists have identified a protein produced by pregnant
lizards, which could help to explain the origins and treatment of cancer in
humans.
An international team, led by Bridget Murphy of Sydney
University, has discovered the protein known as VEGF111, which is pivotal to
development of lizard placenta as it helps blood vessels grow in the uterus
during pregnancy.
"Our egg-laying ancestors probably never got
cancer, but things changed when we started having live young. Embryos need an
extensive network of blood vessels to allow them to grow. So do tumours.
"I found that the three-toed skink, which gives birth to live young,
uses a particularly powerful protein to encourage the growth of blood vessels.
The only other place where this protein has been found is in pre-cancerous cells
grown in the laboratory," Murphy said.
According to the scientists,
future research on unlocking the secrets of how the protein works might provide
the basis of new therapies for cancer, and to promote wound healing or the
regeneration of blood vessels in patients with heart disease.
The
protein belongs to a group known as vascular endothelial growth factors which
help to produce blood vessels in the uterus during pregnancy.
"Both
tumours and embryos must develop an extensive network of blood vessels which
bring in oxygen and nutrients to allow them to grow. And they both must avoid
rejection by hiding from the immune system of their host.
"In fact,
many researchers think that cancers have hijacked the molecular machinery that
originally evolved to allow embryonic development. It may be that animals that
give birth to live young, such as humans and some lizards, have an increased
susceptibility to cancer," Murphy said.
Using techniques to measure
which of the VEGF genes were present and active in lizards, the team discovered
the first known natural source of VEGF111 in the three-toed skink, a shy
Australian lizard which lives underground.
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