So why would cancerous cells, that act abnormally to a normal healthy cell, be used in all these studies?
In: Biology
They’re immortal *because* they’re cancerous.
Basically, cells have a limit to how many times they can divide – the “hayflick” limit. It’s determined by the length of some special DNA called a telomere.
In a normal cell, each time it divides, those telomeres shorten. In some cancers, they don’t – due telomerase enzymes.
As a result, the cell never hits the built – in limiter. And keeps dividing, forever. Which is both part of what makes it a cancer, and why it’s immortal.
In terms of “why use a cancer cell for all those studies”, well, logistics. Having cells you can rapidly grow in a predictable manner is valuable.
And not all studies use HELA cells or even immortalised cell lines. But many do, because they’re logistically useful
Well a lot of times Hela cells are just used as a useful cell for doing all sorts of experiments. For example I worked on HIV. We had a DNA genome for HIV (in a thing called a plasmid, basically a circle of DNA). I made a lot of mutations in the HIV virus which I would do in these bits of DNA. Note this DNA is not infectious. But after making my mutations I needed to make live HIV viruses to test the effects of those mutations (these mutations were done to learn about various functions for different parts of the HIV virus). We would take this HIV genome in the DNA, introduce it into Hela cells in tissue culture, and then the Hela cells would start making live HIV viruses. I could then take that virus and do whatever experiment I wanted to do. Hela cells for me were sort of like a work horse cell that grew well, stuck to the bottom of the plate and you could use it for this and other purposes. Kind of like a handy tool.
Historically speaking, we just couldn’t grow human cells outside the body at all for a long time. Researchers lucked into the tumor cells from Henrietta Lacks and found they were functionally immortalized and could be grown in the lab. Our options at that point were basically no human cell lines or HeLa cells, so if studies needed to be done with human cells, they were used and became very popular.
Slowly but surely, we started developing other immortalized human and mammalian cells lines. Some were developed from other cancerous cells, and some were developed from stem cells such as those found in fetuses and embryos. As our options grew, we deviated away from HeLa cells in some places, but we had so much historical data and protocols using HeLa cells that they continued to stick around.
Today, we’ve even learned to make stem cells ourselves from other cell lines, and these “induced” stem cells are also functionally immortal cell lines.
It also helps to have a large variety of studies conducted on the same strain of cells. It means you’ve eliminated a variable.
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