Why Use RNAi?
On the last page, what did you notice about the worm? IT GREW A LUMP ON ITS BODY! That lump is called a tumor or a not normal growth of body tissue. Tumors are usually seen in most cancers. Cancer is a disease that has to do with cells (which are the basic unit of all life). Cancer happens when cells grow and divide too quickly without stopping.
So what can RNAi do to help?
One job of proteins is to tell the cell when to grow and divide but also when to stop! In cancer, there is a problem with this message. Normal cells grow and divide but know when to stop this process and eventually die. Cancer cells never stop growing and dividing. This is why you get a mass of cells called a tumor.
RNAi can be used to test which proteins are important in stopping cell growth. One way this is done in cancer research is by using tissue cultures. Tissue cultures are groups of normal human cells that can be changed in order to have too much growth or normal growth. Scientists are interested in figuring out what makes the cells in tumors keep growing without knowing when to stop. (Remember, normal cells do grow but cancer cells just grow multiple times as much) They use RNAi like you saw on the previous page to knock down certain genes. It is like a guessing game, sometimes you get lucky with the first one you pick but other times you have to try a lot of different combinations first. They try different things and see which one makes the cells grow excessively and which ones show normal cell growth.
Put your thinking caps on! If you knock down a gene and you see lots and lots of cell growth over time are you causing or preventing cancer?