Supposing you wanted to kill off a certain type of cell in your body. Is there an easy way to do this without killing any other types?
Is itposible/feasable to engineer a virus that binds to protiens found only on certain types of cancer cells? Or would you end up targeting the entire type of tissue that spawned the cancer?
1920s Style Death Rays?
If this were easy, wouldn’t you have a cure for cancer?
If you’re talking about cancer cells, then obviously there’s a great deal of effort involved in finding the answer to that question, but nobody knows yet. If you’re talking about any other type of cell, there might be some sorts of cells one could selectively kill off, but most of them serve an important purpose, so their loss would be shortly followed by the death of the entire organism and thus all of the other cells, targetted or not.
In general, no, but in certain specific cases, yes, it can be done. This is how they treat certain types of cancers and thyroid problems. You have to have some way of distinguishing between cells, like for example the fact that the thyroid actively accumulates iodine. If you give a patient radioactive iodine, it’s going to kill more thyroid cells than anything else because of this, which is how hyperthyroidism is treated.
The hard part is finding something distinctive about the cells in question that you can use to your advantage. Most cells don’t have something simple (like iodine) that you can use to only target those cells with.
With viruses, there are certain proteins on the cell surface that the virus can attach to. Some viruses and host cells are more specific than others. If you think in terms of keys and locks, imagine a large building, like a college dorm. Each dorm room has a key (or set of keys) that opens that room and that room only. In addition, there is a key that will open any room on a given floor and also a key that will open every room in the whole building. If you need to let someone get in to room 412, you can give them a key for 412, a key for the fourth floor, or the building master key. If you have top secret porn mags in, say 413 that you don’t want them to see, you give them the key for 412, of your TSPM’s are in 605, you can give them the fourth floor key, the key to 412, but not the building master. If you need to have someone check all the rooms on the fourth floor for the TSPM’s, it is easier to give them one key for the fourth floor, instead of individual keys for each room.
Like Chronos said, in the body, it is really hard and expensive to target an individual cell. Most antibiotics work by attacking a specific sugar structure that is only in bacterial cell walls, not human cells. Also, this explains the side effects of medications. Cancer treatments usually target rapidly growing cells, since that’s what tumors are. But, your digestive tract is also made up of rapidly growing cells, so is your bone marrow, and your immune system.
To sort of answer Inigo’s question, I’m sure it is possible on some level, but often you kill off almost everything and wait for it to grow back or replace it with new. In some leukemia treatments, they wipe out the patient’s bone marrow completely and replace it in a transplant, in others they wipe out almost all the bone marrow and let the rest recover and hope that the healthy cells outgrow the cancer cells.
Of course, there are chemicals that target certain tissues. Alcohol and Acetometaphin are more damaging to the liver than to other tissues. Lead is more detrimental to the brain than other tissue.
If you can find an antigen that’s specific to the cell type you’re interested in, you can create antibodies against it, then attach something lethal to those antibodies. The cancer treatment Gleevec is a synthetic antibody that blocks a cancer-specific protein signal.
Gleevec is a small molecule kinase inhibitor, Smeghead, not an antibody, you must be thinking of somethig else.
This is an excellent question. I am currently undergoing chemotherapy. Right before I started, there was news of a new treatment for cancer which only targeted cancer cells, while leaving normal cells alone. It is called Adeno-Associated Virus Type 2 or AAV-2. Apparently, it has shown great results in Uterine and Breast Cancers. They did say that they needed more research and that it probably wouldn’t be available for at least two years. From what I can remember from the info, we all have this virus in our body but it must be activated to work. I think to activate it, you need to be injected with something. Sorry to sound vague, but I haven’t heard anything more about this new treatment (much to my chagrin). However, I am halfway through my treatments and will hopefully never have to go through this again.
If anyone else has heard of this treatment, please feel free to correct me or tell me more about it.
This is my first post!
There is a product that does that: Onconase.
http://www.onconase.com/
http://www.news.wisc.edu/wire/i090998/onconase.html
It’s currently in Phase IIIb clinical trials.
Currently chemotherapy works by kiling off all cells at a certain point in the cell cycle (eg metaphase, telophase or prophase). We usually combine chemotherapy agents so that all cells in say telophase and metaphase are killed off.
As cancer cells replicate more than normal cells they spend longer in these replicatory phases, and so a higher proportion of cancer cells than normal cells is destroyed. Unfortunately any normal cell that also happens to be replicating at the time is also destroyed.
Which is why the side effects of chemotherapy include mouth ulcers (highly replicating cells in the lining of the mouth), hair loss (hair is often in one of the replication stages), and damage to the gametes (which are also in one of these sensitive stages of the cell cyce).
Cancer cells are abnormal in many ways, and targeting one of these abnormalities that doesn’t occur in normal cells is the best way of selectively targeting cancer cells. that’s the ultimate goal, but we’re a little way off that.
You are, of course, correct. I got some wires in my head crossed. Now I’m going to go nuts trying to remember what it was I was thinking of…