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Sinemetu9 t1_j3duxzv wrote

Reply to comment by [deleted] in How does DNA encode 3d space/information? by Rit2Strong

So how does cancer work? In my mind, the cells’ programming goes AWOL and they just keep replicating and acting, regardless of procedure protocols. How true is that?

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CrateDane t1_j3dx1jp wrote

Your cells have, for example, some "programs" that tell them to grow and divide, and some programs that tell them to commit suicide. Those programs are normally only turned on when appropriate.

In a cancer cell, mutations cause one or more programs telling the cell to grow and divide to be constantly turned on, and the suicide programs to be broken (so even if it would be appropriate, they will not commit suicide).

There are some other programs that tend to be broken in cancer cells too, but those are two of the main ones.

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Sinemetu9 t1_j3dy6pe wrote

What can reprogram them?

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YandyTheGnome t1_j3dzips wrote

Usually it's damage to the pathway that activates this cell suicide. The body signals for it to die off but it doesn't respond to the signal. This can happen in numerous different ways, as evidenced by the multitude of types of cancers.

Edit: as an example, damage from ultraviolet light causes many cells to die off, in the form of sunburn and the blistering that follows. Some cells get mutated but don't die, and can become skin cancer.

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CrateDane t1_j3dzd0g wrote

Mutations. Those can be caused by many things, most often either DNA damage from the cell's own metabolic byproducts or mistakes made when growing/dividing cells replicate their DNA.

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artlabman t1_j3ec1nk wrote

Is cell death still called apoptosis??

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CrateDane t1_j3egc41 wrote

It used to be we thought of just apoptosis and necrosis, with apoptosis being a clean and deliberate suicide, while necrosis was a messy and uncontrolled cell death.

While those are still very valid, it's turning out that there are a lot more ways for cells to die.

There's necroptosis which is controlled like apoptosis, but messy like necrosis. There's ferroptosis which is iron-reliant and happens in response to excessive oxidation. There's anoikis, which is very similar to apoptosis but initiated by lack of contact to extracellular matrix. There's NETosis, where a type of immune cell called neutrophils eject their DNA as a sticky net to capture pathogens. There's pyroptosis which is triggered by the inflammasome and strongly stimulates inflammation to combat mainly intracellular pathogens.

There are a few more I've left out, probably a few more I haven't heard of, and then all the ones we might not have discovered/characterized yet.

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artlabman t1_j3eheht wrote

Thanks it’s been almost 30years since I was in college….

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provocative_bear t1_j3edpp2 wrote

Apoptosis is a "planned" cell death, where either the body commands the cell to kill itself because it's no longer useful or the cell is mortally wounded and dies a tidy death by suicide for the good of the body.

In contrast, cell necrosis is sudden, "messy" cell death that is not considered apoptosis. It can cause problems for surrounding cells as debris, signaling molecules, and even digestive enzymes get released uncontrolled from the dying cell.

Cancer cells are damaged (usually genetically) in a way that causes them to ignore the body's signals to commit apoptosis, but also to ignore signals to not divide and to stay where they are.

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Yitram t1_j3ei7t8 wrote

You're not wrong. Think of cells as a factory making a product. In cancer, not only is the product wrong but you can't shut off the factory. Also why cancer is so awful if you get it younger. To go back to the factory analogy, in a young person, the factory is shiny and new and efficient, so it makes the cancer really fast. Whereas in an older person, the factory already isn't in the greatest of shape, even before the cancer.

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Mr_HandSmall t1_j3e3j6k wrote

Cells are always having a few mutations in their DNA, but there are systems in the cell that will recognize excess mutations and kill the cell before it can cause problems.

Things can really start to get out of hand when you get mutations in those proofreading systems themselves. Then you get a set of cells that can start mutating freely. Eventually natural selection takes over and the mutant cells keep accumulating more and more mutations that help them replicate and spread, leading to cancer.

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mpinnegar t1_j3e99t2 wrote

Cells have a variety of processes going on inside of them to do things like maintain homeostasis, replicate, fix DNA errors, produce power, etc. They even have machinery to self terminate when something goes wrong.

In a cancer cell one of the processes has broken down and the self termination process has ALSO broken down. Once that's happened you essentially have a rogue cellular factory inside of your body that can hijack the resources you need to survive and can replicate itself going from one cell to enough to kill you by any number of factors. The cancer could just physically put pressure on organs like the brain. It could produce a wild amount of signaling hormones therefore causing secondary non-cancerous cells to follow erroneous instructions. It could also take over resources that other parts of your body need to survive.

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Trips-Over-Tail t1_j3dve7w wrote

Pretty much. They don't do much normal stuff beyong replication and releasing hormones that stimulate capillary growth to keep them fed.

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Sinemetu9 t1_j3dxqlc wrote

Ok thank you. So the procedure protocols can be disrupted by environmental influences eg. radiation poisoning, and by genetic, inheritable weaknesses in coding checking procedures? Why don’t the surrounding cells say ‘hey, you’re going crazy, stop!’?

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Mr_HandSmall t1_j3e4y20 wrote

> Why don’t the surrounding cells say ‘hey, you’re going crazy, stop!’?

A cancerous cell might develop a mutation that would reduce the amount of a protein on it's surface that would normally be recognized by immune cells trying to kill cancerous cells.

No two cancers are exactly alike on a genetic level, even though may have the same medical label. Each is a unique collection of many mutations that lead to a cell population that can replicate, invade, evade immune detection, etc.

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Trips-Over-Tail t1_j3e2fje wrote

They do. Our immune system works very hard to suppress cancerous and pre-cancerous cells all over our body. The ones that become deadly tumours are the ones that by chance are able to fly under the radar of the immune system. Natural selection.

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pzzia02 t1_j3e3ah3 wrote

Thats about it they stop listening to the "cyclins" that regulates cell replication. This is usually quite common and the body can destroy the cells as long as theyre recognised. When they arent recognised and grow out of control it can get out of hand.

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