Hi, I’ve been reading (and enjoying) the book ‘The Immortabl Life of Henrietta Lacks’, but am having trouble comprehending the scientific issues raised in the book (especially on the topic of contamination) due to the fact that I can’t seem to fully grasp the use of Hela cells. I’m not a STEM student! I’ve googled and browsed some posts here but still have questions, mainly:
* I understand Hela cells were the first to become ‘immortal’ as they were able to continue dividing outside the human body without dying. I’ve read that this helps in research as you could culture a large amount of samples to test on. However, I’ve also read that the Hela cells have mutated to the point that they don’t ressemble human cells anymore (they have 80 chromosomes!)
**My question is:** Did they start mutating after being cultured and distributed so many times (and labs actually have different versions of the cells), and if so, how does that help with research? Don’t you need exact copies of a cell to conduct experiments so you have a contolled factor? (Or is this unnecessary?) If someone can explain in a more specific way how Hela cells are used to make discoveries that would be great!! (For example, I know they used it to map the human genome by merging it with monkeys and matching enzymes with chromosomes)
* On the topic of contamination, from my understanding, halfway through the book scientists started realizing that their experiements with cell lines (Originally thought they were using Hela cell lines but have read in some posts that they were actually using other immortal cell lines they’ve cultured?) might be invalidated because they may have been contaminated by Hela, meaning they have been experimenting on contaminated cell lines all along. (Apologies I’m very confused by this part, so this is just my current understanding!)
**My question is:** Even if the cell lines they were using to conduct their experiments were contaminated by Hela, how does this affect the results of their research? Wouldn’t scientist know what kind of cell they are working on (contanimated or not)? I guess this question ties in with the first question, as I don’t understand how these experiments work, I can’t grasp the severity of experimenting with a contaminated cell.
Would love some help, as I’m really stuck on a whole concept even though I’m already halfway through the book:/ Thanks!!
In: 1
The cells were immortal to begin with. Immortal in this context means that they don’t respond to signals that tell the cells to die. One of the processes that cancer develops is called “immortalisation” where it stops responding to death signals from the body and can keep growing. But it still needs nutrients and things to function.
Another thing with cancer cells is that they lose the ability to fix random mutations. That’s essentially what happened with the HeLa cells after we started culturing them. They increased n chromosomes because they don’t apoptose (kinda like cell suicide) when they run into that problem like normal cells do. Normally you would die long before a cancer got to this state but because we kept growing HeLa cells, these mutations accumulated more and more.
The contamination is that the cancer cell lines (HeLa is a cell line, there are other cell lines that we have collected for experimentation over time) all grow in very similar situations and you can’t really kill off the contaminated cells easily. So you could accidentally contaminate another cell line with HeLa cells and now you have both in the same dish. You’d only find out after you look at them in a microscope and see that your cells are different. The contamination may or may not matter, it depends on the research. As it becomes more and more mutated and different to normal human cells, the question of how well it models and represents a human cell becomes more important. If you’re testing a cancer treatment for a particular type of cancer then having contaminated HeLa cells would affect your measurements.
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