Osteopontin (Secreted phosphoprotein 1) (OPN)

Osteopontin (OPN), also known as Secreted phosphoprotein 1 (SPP1), is a multifunctional matricellular protein and cytokine that plays a critical role in immune response and tissue remodeling (UniProt: P10451; PMID: 29361988). It is predominantly secreted by activated monocytes and macrophages in response to pro-inflammatory signals, acting as a potent chemoattractant and survival factor for these cells (PMID: 18248824). OPN functions by interacting with various cell surface receptors, most notably integrins (such as αvβ3 and α9β1) and CD44, which activates downstream signaling cascades like PI3K/Akt and MAPK (PMID: 29361988). In pathological conditions, the overproduction of OPN is linked to chronic inflammatory diseases, such as rheumatoid arthritis and atherosclerosis, as well as the progression and metastasis of various cancers (PMID: 29361988; PMID: 27190501). Therapeutic interventions targeting the OPN secretion pathway or its receptor interactions, including monoclonal antibodies like ASK8007 and small molecule inhibitors, are being explored to reduce pathological inflammation and inhibit tumor growth (ClinicalTrials.gov: NCT00411814; PMID: 27190501).

Other names

Secreted phosphoprotein 1SPP1Bone sialoprotein IEarly T-lymphocyte activation 1 proteinETA-1NephropontinUropontin

Inhibition of Osteopontin binding to integrin and CD44 receptors