The phosphoinositide 3-kinase pathway and therapy resistance in cancer

The phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling network is a master regulator of processes that contribute to tumorigenesis and tumor maintenance. The PI3K pathway also plays a critical role in driving resistance to diverse anti-cancer therapies. This review article focuses on mechanisms by which the PI3K pathway contributes to therapy resistance in cancer, and highlights potential combination therapy strategies to circumvent resistance driven by PI3K signaling. In addition, resistance mechanisms that limit the clinical efficacy of small molecule inhibitors of the PI3K pathway are discussed.