Phosphatidylinositol 3-kinase-protein kinase B signaling axis (PI3K-Akt axis) (PI3K-Akt axis)

The Phosphatidylinositol 3-kinase-protein kinase B (PI3K-Akt) signaling axis is a central intracellular pathway that coordinates cellular responses to external stimuli such as growth factors and insulin (StatPearls, 2023). Upon activation of upstream receptors, PI3K phosphorylates membrane lipids to create PIP3, which serves as a docking site for the serine/threonine kinase Akt (NIH, 2024). Once localized to the membrane, Akt is activated via phosphorylation and subsequently regulates a vast array of downstream effectors involved in protein synthesis, glucose metabolism, and the inhibition of apoptosis (PubMed, 2022). This pathway is frequently hyperactivated in human cancers through gain-of-function mutations in PIK3CA or loss-of-function mutations in the lipid phosphatase PTEN, which normally acts as a brake on the system (Nature Reviews Cancer, 2021). Because of its pivotal role in oncogenesis, the PI3K-Akt axis is a high-priority therapeutic target, leading to the development of isoform-specific PI3K inhibitors and allosteric Akt inhibitors (Journal of Clinical Oncology, 2022). Clinical use of these agents, such as alpelisib and capivasertib, has demonstrated efficacy in treating specific breast cancer subtypes and hematologic malignancies (FDA, 2023). However, because the axis is also the primary mediator of insulin signaling, pharmacological inhibition often results in systemic metabolic disturbances, most notably hyperglycemia (Cell Metabolism, 2021). Managing these toxicities remains a significant challenge in the clinical application of drugs targeting this signaling cascade (The Lancet Oncology, 2023).

Other names

PI3K/Akt pathwayPI3K-PKB signaling pathwayPhosphoinositide 3-kinase-Akt pathwayPI3K/Akt/mTOR signaling axis

Inhibition of the catalytic activity of phosphoinositide 3-kinase (PI3K) isoforms or the serine/threonine kinase Akt (Protein Kinase B) to disrupt the signaling cascade that promotes tumor cell growth and survival.