Forthcoming Research on Deriving Adult Stem Cells
A press release on PR Newswire
describes an article to be published in the next issue of the journal Stem Cells
. Scientists at The George Washington University Medical Center in Washington, D.C. have developed a method to create stem cells lines from umbilical cord blood.
Stem cells' key laboratory property is the ability to continue to divide and differentiate; normal human cells only divide a limited number of times in cultures, after which they enter a period known as senescence. This is generally from the loss of DNA sequences at the ends of chromosomes which occurs over repeated divisions. Stem cells produce an enzyme, telomerase, which adds repetitive DNA to the chromosome tips. Other causes of senescence in adult cells involve tumor suppressor pathways. In this study, the researchers were able to keep the adult stem cells from entering senescence by artificially expressing telomerase and simultaneously inactivating tumor suppressor pathways. The researchers also showed that these cells could be converted to leukemic cells (since the tumor suppressor is inactivated), which would allow for ways to study leukemia treatments. The cell lines produced do contain chromosomal abnormalities, some of which are similar to those that have appeared in embryonic stem cell lines.
I am interested in this study because being able to create self-replicating adult cells in the laboratory seems a fruitful way of moving beyond the need for embryonic stem cells, but I think the researchers have a long way to go to overcome the genetic changes and the possibility of malignancies. Balancing the need for quick differentiation and division in healing against the unchecked growth of cancer is probably one of the biggest challenges facing stem cell researchers today.