Shared protein patrols proliferation of stem cells and cancer cells

According to a new study, the same protein may control the proliferation of stem cells and cancer cells.

The findings of the new study will help researchers understand how both types of cell can divide indefinitely. However it also indicates concerns that stem cell transplants may cause seeding cancers.

The discovery should assist scientists in manipulating stem cells to give an unlimited source for use in medicine, says Robert Tsai at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. The hope is that stem-cell therapy will eventually be able to replace or repair any damaged tissue in the body.

To achieve this, scientists must control proliferation to ensure the transplanted cells don’t become cancerous. More researchers should be “paying attention to the molecular events that take part in the earliest stages of stem cells,” says Julia Polak, director of Imperial College London’s Tissue Engineering and Regenerative Medicine Centre.

The body maintains the ability for certain stem cells to renew themselves allowing them to replace cells that wear out. This property is hijacked by cancer cells to transform into dividing tumours. The molecular link now established between stem cells and cancer cells “is something novel, as far as I’m aware,” says Polak.

Tsai, and his colleague Ronald McKay demonstrated that the protein nucleostemin is abundant in self-renewing cells such as mouse embryonic and neural stem cells and several human cancer cell lines.

In contrast, research shows that the protein is scarce in the mature cell type and can no longer divide. Increasing or knocking down the level of nucleostemin in neural stem cells and cancer-like cells in the lab reduced their proliferation.

Researchers do not yet know the exact function of nucleostemin, it appears to behave like a molecular switch to control cell division. The researchers also showed that it binds to a protein called p53, which regulates cell proliferation and is implicated in many cancers.

(Source: British Journal of Cancer)