January 24, 2015
Telomere Lengthening RNA Treatment Lets Cells Divide More
Take away the threat of cancer and I'll sign up for telomere lengthening.
Researchers delivered a modified RNA that encodes a telomere-extending protein to cultured human cells. Cell proliferation capacity was dramatically increased, yielding large numbers of cells for study.
This result suggests that the Hayflick limit on how many times a cell can divide is caused by telomere shortening that happens every time a cell divides. Once the telomeres on chromosomes get too small the cell loses the ability to divide. This is an expected result. Telomere shortening has long been thought to be a defense mechanism against cancer by limiting how many times a cell can divide.
Yet we still get and die from cancer. Why? Cancer gets around it by mutations to turn on telomerase to lengthen telomeres as well as probably by other mechanisms. But the need for the additional mutations decreases the odds of dying of cancer - albeit at the cost of dying from aging. Our cells gradually lose the ability to divide to do repair and we become decrepit and malfunction and die.
This technique is useful for scientists who need long living cell lines.
A new procedure can quickly and efficiently increase the length of human telomeres, the protective caps on the ends of chromosomes that are linked to aging and disease, according to scientists at the Stanford University School of Medicine.
Treated cells behave as if they are much younger than untreated cells, multiplying with abandon in the laboratory dish rather than stagnating or dying.
There are two problems with using this technique on our bodies. First, getting it into all the cells would be hard. Second, it would increase our odds of getting cancer. What we need: the ability to kill pre-cancerous cells that have some but not all the mutations needed to make a cell cancerous. Once we can wipe out those cells we will be able to use gene therapy to lengthen our telomeres. The result would be that all over the body a lot more repair would get done and people would become healthier.
What I'd like to know: what fraction of 60, 65, 70, 75 year old people have cancers being held at bay by short telomeres? If 65 year olds all got their telomeres lengthened what fraction would die sooner of cancer an what fraction would live longer and healthier due to better body repair?
Randall Parker, 2015 January 24 07:46 PM
I don't see a substantive danger of cancer in this treatment. If one-time telomere lengthening is a cancer hazard, why aren't 20 year olds dropping like flies from cancer? Its not mere telomere lengthening that is the problem. Its dynamic lengthening of telomeres (hyper-activation of telomerase) that causes cancer.
I hold with James … While I understand Randall's worry about cancer, I think he is a littl too wary. If I were 75, I'd roll the dice and take the treatment.
20 year olds do not have as many DNA mutations. The older you get the more likely a dangerous combination of mutations will all happen in the same cell and cause cancerous growth.
Given the right circumstances (e.g. an organ so badly in need of repair that I'd die in a few years without repair) I'd probably roll the dice too. If your odds of dying from a non-cancer disease are high enough then getting your telomeres lengthened makes more sense.
Some attempt at arithmetic sense here that I've never seen anyone even try to work out:
The telomere loss amounts to 50 to 100 base pairs per doubling so if we're lucky, the few thousand base pairs that would be added by telomere lengthening would amount to 2^(3000/100) = 2^30 or a billion cell tumor. The body is a couple hundred billion cells so we're talking a 1lb tumor. If we're unlucky the tumor would be 2^(3000/50) = 2^60 or about as many cells as there are in the US population.
It seems to me that people walking around with several thousand base pair telomeres -- like most teens -- are running a pretty serious risk given all those hundreds of billions of cells -- only one of which has to go haywire.
Something more is needed for a rational handle on this.
I've always assumed that one of the factors in cancer was an immune system unable to sweep out little cancers colonies before they become a problem. Hence the increase in cancer with age coinciding with a weaker immune system. So if coupled with immune system rejuvenation, telomere lengthening could be a net plus.
Not quite right, James, in as much as a billion cell tumor is a billion opportunities for the cancer to find it's own way to lengthen telomeres, and then not stop at one billion cells. But generally correct, the direct danger of this is fairly minor compared to the potential benefit for us old fogies.
I think this probably would be beneficial in a procedure where you remove cells, and culture them outside the body, perhaps with modifications, and then reintroduce them. You'd want to rejuvenate them, too, instead of using up their limited number of divisions just culturing them.
Perhaps at the same time you could engineer in a mix of apoptosis triggers, so that if any of the reintroduced stem cells went rogue, it's particular cell line could be killed off.
I have read that the average person gets cancer twice a day.The immune system fights it off.Obviously,the immune system is all important.
It is all about the survival of the species not the individual. If we want to live longer we need to rejuvenate the thymus.
I heavily doubt on the latest atomic treatments. When I say atomic I actually mean micro treatments. I strongly believe we should follow natural treatments. Like treatments using trees, herbs etc. But genetic engineering still couldn't able to prove it harmless and useful.
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