One of the many jobs of haematopoietic stem cells is to keep in balance the normal expansion of cell numbers in the bone marrow without creating an overabundance of cells that may lead to leukaemia. A tipping point of this fine balance may have been found in a signalling molecule known as phosphatase and tensin homologue, or PTEN.
In a study to be published online by Nature, Linheng Li and colleagues show that this molecule, which normally keeps in check the phosphatidylinositol-3-OH kinase (PI(3)K) proliferation pathway, is crucial in this process. The researchers placed bone marrow stem cells containing an inactive form of PTEN into recipient mice and found that these mutant cells generated more myeloid and T-lymphoid cells, mimicking the onset of myeloid and lymphoid leukaemia.
Pinpointing the difference between leukaemic stem cells and haematopoietic stem cells with molecules such as PTEN may one day lead to more targeted therapies that can better distinguish between cancer and normal stem cells.
Linheng Li (Stowers Inst for Medical Research, Kansas City, MO USA)
Abstract available online.
(C) Nature press release.
Message posted by: Trevor M. D'Souza