New Clues To Understanding Cancer

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In the 13th January print edition of the journal Current Biology, Instituto Gubenkian de Ciencia scientists provide insight into an old mystery in cell biology, and offer up new clues to understanding cancer. Ins Cunha Ferreira and Mnica Bettencourt Dias, working with scientists at the universities of Cambridge, UK, and Siena, Italy, unravelled the mystery of how cells count the number of centrosomes, the structure that regulates the cell's skeleton, controls the multiplication of cells, and is often transformed in cancer.

This research addresses an ancient question: how does a cell know how a number of centrosomes it has? It is equally an important question, since both an excess or absence of centrosomes are linked to disease, from infertility to cancer.

Each cell has, at most, two centrosomes. Whenever a cell divides, each centrosome gives rise to a single daughter centrosome, inherited by one of the daughter cells. Thus, there is strict control on progeny! By using the fruit fly, the IGC scientists identified the molecule that is responsible for this 'birth control policy' of the cell a molecule called Slimb. In the absence of Slimb, each mother centrosome can give rise to several daughters in one go, leading to an excess of centrosomes in the cell.

In recent years, Monica's group has produced several important findings relating to centrosome control: they identified another molecule, SAK, as the trigger for the formation of centrosomes. When SAK is absent, there are no centrosomes, whereas if SAK is overproduced, the cell has too a number of centrosomes. These results were reported in the prestigious journals Current Biology and Science, in 2005 and 2007. Now, the group has discovered the player in the next level up: Slimb mediates the destruction of SAK, and in so doing, ultimately controls the number of centrosomes in a cell.

Monica explains, 'We carried out these studies in the fruit fly, but we know that the same mechanism acts in mice and even in humans. Knowing that Slimb is altered in several cancers opens up new avenues of research into the mechanisms underlying the change in the number of centrosomes seen in a number of tumours'.

Mnica first got interested in centrosomes and in SAK when she was an Associate Researcher at Cambridge University, UK, and has pursued this interest at the IGC, where she has been group leader of the Cell Cycle Regulation laboratory since 2006. Ins Cunha Ferreira travelled with Monica from Cambridge, and is now in her second year of the in-house PhD programme. Two other PhD students in the lab also contributed to this research, Ana Rodrigues Martins and Ins Bento.


Posted by: Janet    Source