Scientists have worked out how cancer cells change their shape to spread around the body. They found that melanoma cells rapidly alternate between a round
shape and a more stretchy "elongated" shape to help them move in
different environments and reported their findings in the journal, Cell. Melanoma, the most dangerous form of skin cancer, is particularly aggressive.
The spread of cancer cells from the initial tumour
to other sites of the body, a process known as metastasis, is one of
the biggest problems in treatment. The researchers were able to view cells in live tumours rapidly undergoing these changes in shape.
When Rac is switched on it encourages the
cell to become elongated and simultaneously suppresses the activity of
the competing Rho protein. Conversely, when cells adopt the round form, a protein activated by Rho switches off Rac activation.
These alternate shapes may enable tumour cells to deal with different situations during cancer spread. So far, tests suggest that a round-shaped tumour cell may be better equipped to survive in the bloodstream than elongated cells.
It is not yet clear whether these findings apply to just melanoma, or to other types of cancer as well. This improved knowledge about the biology of how cancer spreads may help scientists develop new technologies to better target the cause of the disease.