Human cells made immortal in vitro through the use of the enzyme telomerase were recently shown not to transform into cancerous cells. This finding will enable leukemia patients and others to benefit from the use of these cells.
Researchers at of the University of Texas Southwestern Medical Center discovered that by introducing the enzyme telomerase, one could indefinitely extend the lifespan of human cells. Telomerase builds up the telomere, which is the DNA found on the end of chromosomes that controls the amount of times a cell can divide and which shortens with age. Telomeres degrade as the cells divide and their shortening causes cell death.
After removing a few rare stem cells from a leukemia patient, the cells could be treated with telomerase, grown in large quantities and transplanted into the patient avoiding rejection. This process would make bone marrow transplant unnecessary. The same procedure could also repair genetic defects.
Dr Woodring Wright, head of the research team stated,``There has been a lot of confusion (however) because of concern that the association of telomerase with cancer implies that normal cells expressing telomerase would have the characteristics of cancer cells.'' Even though cancer cells contain telomerase and exhibit immortality,Wright's team has provided evidence that normal cells that are manipulated to express telomerase ``exhibit absolutely none of the characteristics that one associates with tumor cells.'' This finding was confirmed by another study conducted by Gerona Corporation.
