Forkhead box protein O3 (FOXO3) (FOXO3)

Forkhead box protein O3 (FOXO3) is a key member of the O subclass of the forkhead family of transcription factors, characterized by a distinct DNA-binding forkhead domain (UniProt: P98177). It serves as a critical integrator of various cellular signals, including growth factors, oxidative stress, and nutrient availability, primarily regulated by the PI3K/AKT signaling pathway (PubMed: 10102273). When AKT is active, it phosphorylates FOXO3, leading to its sequestration in the cytoplasm and subsequent degradation, thereby inhibiting its transcriptional activity (PubMed: 21307345). Conversely, under stress or low growth factor conditions, FOXO3 translocates to the nucleus where it triggers the expression of genes involved in cell cycle arrest, apoptosis, and DNA repair (PubMed: 15034584). In oncology, FOXO3 is generally considered a tumor suppressor, and its inactivation is frequently observed in various cancers, making its reactivation a significant therapeutic strategy (PubMed: 24161924). Beyond cancer, FOXO3 is strongly associated with human longevity and plays protective roles in cardiovascular and neurodegenerative diseases by managing oxidative stress and maintaining cellular homeostasis (PubMed: 18765806). Therapeutic modulation of FOXO3 often involves indirect targeting via PI3K/AKT inhibitors or direct stabilization of its nuclear presence using XPO1 inhibitors like Selinexor (PubMed: 25100771). Its pleiotropic nature makes it a complex but promising target for age-related diseases and metabolic disorders (PubMed: 22451204).

Other names

FOXO3AFKHRL1Forkhead in rhabdomyosarcoma-like 1FOXO3 transcription factor

Activation of FOXO3 transcriptional activity through inhibition of upstream negative regulators (e.g., PI3K, AKT) or inhibition of nuclear export (XPO1) [PubMed: 25100771, 10102273].