How are researchers treating osteosarcomas that are caused by over expression of the PI3K/mTOR pathway?
mTOR phosphorylates 4EBP1, which causes it to release the initiation factor eIF4E, which is required to initiate translation. (eIF4E binds to the 5' mRNA cap and recruits the small subunit to initiate translation.) If this process is overexpressed, then cancer can result. If you inhibit mTOR, 4EBP1 remains unphosphorylated and active, blocking the initiation factor. With IF blocked, the cell cycle cannot continue with initiation of translation, and the growth of cancer cells is inhibited.