The gene, called Arf, prevents the accumulation of certain cells, called pericytes, which nurture the growth of blood vessels in the eye during embryonic development. In normal circumstances a protein produced by Arf blocks the growth of pericyte cells after the early part of embryonic eye development, and as a result the blood vessels die. It is only after this has happened that the eye can grow to its proper size.
If Arf is absent during this time the eyes will not grow properly, causing a child with this condition to have abnormally small eyes and poor vision.
“The Arf gene is well known for its ability to sense when a cell is being overly stimulated to grow,” said Dr Stephen Skapek, an assistant member of the Department of Hematology-Oncology at St Jude. “Arf then helps to trigger a series of signals to block cell proliferation. In the developing eye, we’ve demonstrated that Arf also blocks signals that would otherwise cause pericytes to reproduce and support the continued growth of blood vessels in the developing eye.”
The discovery of the role of Arf in curtailing growth of blood vessels in the developing eye might also contribute to development of new anticancer drugs.
“If we can figure out how to re-activate the Arf gene in human cancers in which this gene is repressed, we might be able to prevent the accumulation of perivascular cells that support the blood vessels that feed a tumor,” Skapek said. “A drug that lets us starve those solid cancers would be a powerful new weapon against cancer.”