Research on the eyes of fruit flies reveals new truths for cancer research
Brona McVittie reports
Sarah Palin might be rather shocked to learn that she has thousands of genes in common with the fruit fly (watch video). Yet for this very reason flies are key to understanding human diseases like cancer. For more than half a century scientists have been using Drosophila melanogaster as a tool to better understand biological development. This work has fuelled many major breakthroughs in cancer research.
A recent PLoS publication is no exception. Speculations from a group of Belgian biologists led them to uncover a genetic switch in flies that could be used to turn off cancer in humans. The scientists wondered whether genes that act as master switches - controlling the maturation of cells in a developing embryo - might be relevant to cancer. Their hunch was based on the observation that cancer cells in many respects appear to be 'immature'.
The team investigated a master gene (ato) involved in eye development in flies. The equivalent gene in humans (ATOH1) is a known tumour-suppressor. The team compared flies with a working copy of the gene to flies with a disfunctional copy. The latter group showed enhanced tumour formation. Further tests revealed that ato controls the delicate balance between dividing and culling cells during eye development.
In humans and mice the equivalent gene appears to play a similar role in development. Moreover, loss of the protein product of ATOH1 has been reported in human colon cancer cells, where its absence seems to hamper newly made cells from maturing into dedicated gut cells. Clearly the 'immaturity' of cancer cells warrants further investigation.
The silencing of tumour-suppressor genes in cancer is influenced by epigenetic factors such as DNA methylation. Drugs that effectively reverse this silencing by altering such epigenetic marks on DNA are currently being tested. Research of this nature could lead to new cancer therapies based on reactivating or restoring the function of ATOH1 and/or other master genes that play similar roles in the maturation of cells.