Created September 27th, 1996. Updated November 30th, 1996. Copyright 1996 by Duane Hewitt
In a recent report in the EMBO Journal (Volume 15, page 1734) the lifespan of human cell lines in tissue culture has been extended by a technique that extends the telomeres (the ends of chromosomes). There is an enzyme which maintains the integrity of the telomeres which is called telomerase.
Telomerase is an enzyme that is normally active only in cells that give rise to sperm and egg or in some stem cell lines. However when cells become cancerous, telomerase is activated. These cells can then replicate without a limit and this process is called "immortalization" There is currently debate about the actual role that telomerase activation plays in tumour formation.
The function of telomerase in the sex cells is to maintain the integrity of the chromosomes. The sex cells are the only part of us that are biologically required to be immortal. If there was a progressive loss of chromosomes with each generation then this would lead to extinction. There has been some speculation and even a recent book (M. Fossel, _Reversing Human Aging_) about activating telomerase to retard aging.
In the EMBO paper the group was actually attempting to find a treatment that would inhibit telomerase and shorten the life span of cells in culture. Ironically the treatment extended the lifespan of cells in culture.
Telomerase has been proposed to be involved in aging of organisms in addition to its role in tissue culture cell lifespan and cancer. Further studies of telomerase and particularly the construction of transgenic mice with altered telomerase activity may yield insights into both cancer and aging. Telomerase in most cell lines maintains a constant length of telomere. However in this study a mechanism for actually extending the average length of telomeres has been discovered. These insights into the control of telomerase activity will lead to a better understanding of the aging process.
To forward information or give feedback: duane@immortality.org