do cells benefit from being of different age? - (Aug/07/2006 )
One more question that worries me.
Many in vitro experiments put the cells into artificial conditions, like switch from glucose to galactose in yeast, which make them kind of synchronized. It is my understanding that because in such an experiment all the cells are in the approximately same phase of their life cycle, it is easier to make a snapshot of their gene expression. The question however arises how these expression patterns would relate to the in vivo patterns. I think that cells are kind of similar to human or animal society. They may benefit from being of different age through some kind of "small talk" or information exchange. Older cells may send signals to younger cells preparing them to forthcoming changes. If it is true, then that would mean that it is not much sence to study anything in vitro. In vivo behavior will be entirely different anyways.
Of course, it may be a pure fantasy. But the serious question is this: whether or not the in vitro synchronized experiments are generalizable on the in vivo situation? Are there any relevant studies, or any commonly accepted viewpoints?
This is a complicated story that can not be addressed with simple terms. The best answer that I can come up with is: doing in vitro studies is like six blind the elephant. Can the blint men get something? Of course they can. Can they get the whole story? no. Thats why people use lab rodants as the next level of experimental objects, and then ultimately, human clinical trials. Does that address your concern to some degree?
Well, in drug discovery or development realms, it makes sense, of course. Thank you, it helps