Stem cells shed light on cancer's spread
Scientists from Cancer Research UK are closer to understanding how cancer cells spread around the body - following publication of a new study using cutting edge stem cell technology.
Researchers have discovered key similarities in the way cancer cells spread out from a tumour and the movement of stem cells as they form new tissues - a process crucial to an embryo's development.
Their study, published in November's Journal of Cell Science1, has found that a molecule called 5T4 plays an important role in the ability of stem cells to move around. Researchers know that 5T4 is present in many different types of tumour and hope treatments targeted against it could help to combat cancer's spread.
As cancer develops, cells often journey out from a tumour and spread round the body via the bloodstream or lymphatic system. This ability to move around is shared by stem cells early in an embryo's development, as they move into position, divide and specialise into different cell types and tissues.
While embryonic cells begin life with the potential to become any type of tissue in the body, as the embryo develops, distinct stem cells arise with the ability to produce particular tissues. All kinds of stem cell need to be mobile - an attribute they lose as they turn into specialised cell types.
In the new study, scientists at Cancer Research UK's Paterson Institute in Manchester grew mouse embryonic stem cells in the laboratory, in order to investigate their ability to transform into specialised cells.
They found stem cells did not normally contain 5T4, but began to produce the molecule when triggered to transform into other cell types. This process made cells spread out on the surface of culture plates, in a similar way to cancer cells moving out from a tumour.
Cancer Research UK's Professor Peter Stern, lead researcher on the study, comments: "We think we've found a common factor in the movement of embryonic cells during development and of cancer cells during the spread of the disease.
"We originally identified 5T4 by looking for shared properties of embryonic tissues and cancer cells, in order to shed light on cells' growth and movement. In development, the growth and movement of cells is tightly controlled, but not in cancer cells, which is why they can spread around the body.
"We're already using the fact that 5T4 is found in cancer cells, but not in normal tissue, to design immunotherapy against it and are testing two such systems in clinical trials. Our recent work has pinpointed the function of 5T4 and raises the possibility of new treatments to prevent the disease from spreading."
If the results can be replicated in human stem cells, there may also be a secondary benefit. Testing for 5T4 could allow scientists to pick out the best stem cells for regenerating damaged tissues.
Professor Stern adds: "The presence of this molecule seems to accurately predict whether a stem cell will be any good for regenerating tissues or not. That could be a valuable tool to bring stem cell research forward and use it to treat cancer and other diseases.
"Research on human embryonic stem cells remains highly controversial, but our study of their mouse equivalents suggests they could prove extremely useful as a model system for better understanding how cancer cells grow and spread."
Professor Robert Souhami, Cancer Research UK's Director of Clinical Research, says: "Many of the processes which allow tumours to grow and cancer cells to spread around the body are controlled by the same molecules which also help to shape the growth and development of a human embryo.
"By studying fundamental developmental biology, the new study has highlighted a potentially exciting strategy to prevent cancer from spreading - one of the great challenges faced by scientists."
- Journal of Cell Science116 (22) pp.4533-4542