Phosphoinositide 3-kinase–AKT–mammalian target of rapamycin signaling pathway (PI3K–AKT–mTOR pathway)

The **phosphoinositide 3-kinase–AKT–mammalian target of rapamycin (PI3K–AKT–mTOR) signaling pathway** is an intracellular cascade pivotal for the regulation of multiple cellular processes, including signal transduction, cell proliferation, survival, metabolism, and apoptosis. Activation often begins with receptor tyrosine kinases, leading to PI3K activation, generation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3), and subsequent recruitment and full activation of the AKT serine/threonine kinase. AKT phosphorylates many substrates, including mTOR, thereby promoting cell growth and survival and inhibiting apoptotic processes. Dysregulation, hyperactivation (often via mutations in PIK3CA or loss of PTEN), or amplification of this pathway is a central feature of many human cancers and is associated with aggressive disease, chemoresistance, and poor prognosis. Because of its critical role in cancer and other diseases, numerous targeted drugs have been developed to inhibit PI3K, AKT, or mTOR. Targeted inhibition is associated with variable efficacy and toxicity, and frequent resistance mechanisms include compensatory activation through parallel pathways such as MAPK[1][2][3][4][5][6][7]. **Note:** This is not a single molecular target but a multi-component pathway; more granular targeting (e.g., "Phosphoinositide 3-kinase alpha," "AKT1," or "mTOR") is required for precise drug/target matching and database structuring.

Other names

PI3K/AKT/mTOR pathwayPI3K–Akt–mTOR pathwayPI3K–Akt signaling pathwayPI3K pathway

Inhibition of catalytic activity of PI3K, AKT, or mTOR kinases, thereby suppressing downstream signaling involved in cell survival, growth, and metabolism; this leads to increased apoptosis, reduced proliferation, and reduced tumor cell survival[2][7].