Protein Linked to Cancer

Research in mice has shown how over expression (over production) of a small protein allows cancer cells to divide. Normally, when a cell's DNA is damaged, the cell has mechanisms to recognize this damage and prevent the damaged cell from replicating further. One such mechanism is called the intra-S-phase checkpoint. In breast and other cancers there is often an over production of a protein called cyclin-dependent kinase subunit (Cks). Until now the link between Cks over expression and malignancy was unclear. Now it seems that the Cks protein 'over-rides' the intra-S-phase checkpoint mechanism allowing damaged cells to continue dividing and so become malignant. This discovery was a lucky observation arising during basic biological research into cell division. The scientists used a chemical known as thymidine to temporarily halt the cell division process, and to artificially synchronize the growth of two different groups of cells – one with normal Cks expression, and the other with Cks over expression. To the researchers' surprise, the Cks-over expressing cells failed to stop dividing. The finding is expected to lead to the targeting of this mechanism with drugs and diagnostic techniques. - Proceedings National Academy of Science, DOI: 10.1073/pnas.1102434108, 22 Jun 11