Naked Science Forum
Life Sciences => Cells, Microbes & Viruses => Topic started by: Harri on 25/11/2018 22:27:55
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As a complete lay person when it comes to such issues I was trying to clarify something about telomeres after watching a short film on youtube.
Cells divide reduce less telomerase and telemeres consequently get shorter. Cancerous cells can divide and still produce the enzyme telomerase thus ensuring the multiplying cancerous cells keep on multiplying. Denying these cancerous cells the telomerase enzyme would stop their multiplying. Do I have this correct?
If yes then increasing telomerase production would benefit the faster multiplying cancerous cells,
over the healthy cells, correct?
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Human cells stop dividing after about 50-70 divisions - and many of these divisions occur before birth.
- Part of this is due to telomere shortening
- So a cell which turns cancerous in an adult (due, say, to smoking, or a severe case of sunburn) will be very limited in the maximum size to which it can grow - provided it is still subject to telomere shortening.
- and telomerase is turned off in most human cells
For a cancer to become dangerous, it must overcome telomere shortening, by turning on telomerase (a mutation)
- It must also turn off apoptosis: the process by which cells with uncorrectable mutations commit suicide (another mutation)
- It must also generate a blood supply (other mutations)
- And hide from the immune system (more mutations)
It takes quite a number of mutations before a cancer can become dangerous - unfortunately, some people are born with some of these mutations already present, which increases their lifetime risk of cancer.
Denying these cancerous cells the telomerase enzyme would stop their multiplying.
The gene for telomerase is present in every cell - but it is mostly turned off.
A treatment which suppressed telomerase may be one way to limit cancer growth.
Attempts to extend human lifespan by activating telomerase throughout the body would increase the chance of cancers developing.
Some large, long-lived animals like elephants actually have multiple copies of the gene that detects mutations, so that a single mutation in this gene is less likely to turn cancerous.
See: https://en.wikipedia.org/wiki/Peto%27s_paradox
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I guess an activation of telomerase, if it's possible, before a cancer starts developing could be useful? Or even if telomerase was introduced at a young age it could slow down the aging process?
Is telomerase artificially manufactured or taken from animals when it is used in research, such as with mice?