The idea of being immortal has amazed mankind. It is publicized in all kinds of media, from religious texts to action movies. I mean, the concept of living forever is indeed a marvel!
However, if you look at this topic from a scientific perspective, it is almost impossible.
Notice how I used the word “almost” there.
Scientists have discovered that mutated cells can indeed become immortal, or in more scientific terms, transformed.
This phenomenon occurs when a group of cells divides indefinitely. That is, they don’t stop dividing. A major factor behind this is the telomeric protein, which is present in a cell’s chromosome. These telomeric proteins manipulate telomeres to prevent a cell’s death.
Firstly, what are telomeres?
They are a repetitive sequence of nucleotides present at the ends of chromosomes. Telomeres are found in all organisms, including humans. These telomeres are altered to enable cell transformation.
How does this happen?
When DNA duplicates, a part of its telomere disintegrates away, as shown in the diagram called “telomere degradation”. It is this disintegration that causes the death of the DNA. So, to prevent the DNA (and therefore the cell) from dying, the DNA must remain intact. This is where our handy telomeric protein comes into play.
As shown in the diagram, telomeric proteins and an enzyme called TERT (also a telomeric protein) attach to the disintegrated DNA. This lets them lengthen the DNA by adding a TTAGGG sequence of nucleotides to the telomere. Picture this process as a cycle of sorts. The DNA duplicates and loses a part of its telomere, then telomeric proteins add a new part, then the cycle repeats endlessly.
So what’s the outcome of this phenomenon? To put it simply, immortality! Because the DNA never disintegrates fully, the cell continues to live and is thereby transformed.
Transformed cells have quite a few unique properties. Firstly, they grow forever! Another strange quality of theirs is that they pile up on top of each other. This indicates a loss of contact inhibition (where cells stop multiplying once they touch each other). You can see how abundant transformed cells can be in this image:
However, cellular transformation can have another dangerous outcome: cancer.
Cancer occurs when 12 or more mutations happen in the genome. These mutations can affect cell survival, cell fate, and genome integrity. Such rapid proliferation of cells leads to the formation of tumors, and the genomes of these cells within tumors may gain the 12+ mutations required for cancer. This leads to oncogenesis, or the formation of cancerous tumors.
Transformation of cells is an incredibly rare process, but once it happens, it can have drastic outcomes. A famous example of transformed cells is that of Henrietta Lacks. She was taken to John Hopkins Hospital for a tumor in her abdomen in 1951. Lacks was suffering from adenocarcinoma of the cervix. During her treatment, doctors removed cancer cells from her abdomen for culture studies without her consent or knowledge. Cultivation of her cells proved successful, as millions of them are now alive today! Scientists use them to make crucial discoveries. HeLa cells have also taught us the importance of ethics, as Lacks’s cells were removed without her consent. This example shows how fascinating transformed cells can be!
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