Henrietta Lacks was a young woman in the 1950's who had cervical cancer. Before she died a sample of her cancerous cells were taken from her cervix and placed in culture. Her cells began to hastily divide quicker than any cells that scientists had ever seen before. The cells managed to outlive any cells that scientists had previously attempted to culture.
Henrietta's cancerous cells or HeLa cells have become one most popular cell lines in the world, purely due to the fact they seem to divide an infinite amount of times without dying like normal body cells, thus achieving the status of immortality. I find it shocking that Henrietta's cells have lived for far longer in culture, 74 years, than they ever did in the mere 30 years when she was alive.
This made me begin to question:
Why do cancer cells divide an infinite amount of times whereas body cells would simply die after a finite amount of divisions?
|The Telomere at the end of each chromosome|
Later in the book I managed to find a brief answer to my question.
In 1961, Leonard Hayflick found out that cells divide a set amount of times, around 50 divisions, before dying. This limit is imaginatively named 'The Hayflick limit'. The hayflick limit is determined by a small mechanism found at the end of every chromosome, inside every single cell in our body. Each time a cell divides through mitosis, this telomere shortens until it can shorten no more and the cell dies. You can almost imagine it as a ticking time bomb. This shortening is proportional to the age of a person: the older we get, the shorter our telomeres and the shorter the amount of time our cells have to divide before they die.
With cancer cells, they produce a enzyme called 'telomerase' which actively rebuilds their telomere's, meaning that they can carry on dividing for an infinite amount of time.
After finding out this piece of information, it made me wonder:
If we could artificially produce the enzyme 'telomerase' and administer it to ourselves, would we have found secret to living forever and staying young?
In 2010, Dr Robert DePinho of Harvard University conducted a study which solved the answer to this question. He conducted his experiment on mice, whose organs resembled those of an 80 year old person. He gave the mice a drug which switched on the production of telomerase. Surprisingly, after just two months of being given the drugs the mice regained their youthfulness and even their fertility. This hints that one day humans may be able to reverse the effects of aging and become youthful again. This could put an end to age related illnesses such as Alzheimer's disease and save the NHS millions of pounds. With these drugs, we could become real life versions of Scott Fitzgerald's Benjamin Button. It could also mean that women past child bearing age, could once again become fertile and produce a child without the use of in vitro fertilisation.
As good as this sounds, there are many ethical implications with humans having eternal youth, which will most likely mean that telomerase drugs for human use will remain a fragment of science fiction. These implications include the fact that if these drugs were available to everybody, the world would be left with an unsustainable population and there simply wouldn't be enough space for everybody to live on. If these drugs were rational, who would qualify to use them?
Could telomerase inhibiting drugs cure cancer?
As previously explained, telomerase is the element in cancer cells that causes them to divide an infinite amount of times without death of the malignant cell. In theory, this could mean that if we could stop the production of telomerase then this could stop cancerous cells from dividing and cause them to die. When this theory was tested, anti-telomerase drugs did in fact cause cancer cells to die. However, it was found that cancer cells quickly adapted to the loss of telomerase by producing a resistant mechanism which lead again to the lengthening of telomeres. Therefore, in order for this theory to work, drugs need to be developed which will inhibit both telomerase and it's resistant mechanisms.
In conclusion to my research, telomerase has the potential be a very useful component in anti-aging drugs, however due to ethical complications it is unlikely that it would ever be a legal substance. In addition to this, studies into telomerase and how itself and it's resistant mechanisms can be inhibited could provide hope in the future for a cure to cancer. Telomerase is truly an amazing yet harmful substance (due to its cancer progressing nature) and I'm sure there will be many further scientific studies in order to uncover it's mysteries...