Viewing a single comment thread. View all comments

CrateDane t1_j3dx1jp wrote

Reply to comment by Sinemetu9 in How does DNA encode 3d space/information? by Rit2Strong

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.

40

Sinemetu9 t1_j3dy6pe wrote

What can reprogram them?

7

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.

20

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.

9

artlabman t1_j3ec1nk wrote

Is cell death still called apoptosis??

5

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.

15

artlabman t1_j3eheht wrote

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

2

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.

13