Serpin family B member 3 (SERPINB3)

Serpin family B member 3 (SERPINB3) is an intracellular serine/cysteine protease inhibitor in the clade B serpin (ovalbumin) family, originally identified as squamous cell carcinoma antigen 1 (SCCA1). It primarily inhibits papain-like cysteine proteases, particularly cathepsin L, S, and K, and is expressed in squamous epithelia and inflamed or tumorous tissues. SERPINB3 has essential biological roles in regulating apoptosis, immune responses, epithelial differentiation, and the unfolded protein response. It is notably implicated in the pathobiology of various cancers (including squamous cell carcinoma, liver and biliary cancers) where its overexpression is linked to enhanced proliferation, EMT, stemness traits, apoptosis resistance, immune evasion, and chemoresistance. SERPINB3's utility as a cancer and fibrosis biomarker is established, but it is not directly targeted by approved drugs, and its pro-survival, pro-inflammatory effects in tumors represent key therapeutic challenges

Other names

Serpin B3SCCASCCA1SCCA-1T4-AHsT1196Protein T4-ASquamous cell carcinoma antigen 1SCCSCCA-PDserpin peptidase inhibitor, clade B (ovalbumin), member 3

Inhibition of cysteine proteases (blocking cathepsin activity); Suppression of apoptosis signaling by JNK and p38 inhibition; Reduction of mitochondrial ROS and modulation of mitochondrial permeability transition; Modulation of UPR and inflammatory pathways, leading to NF-κB/IL-6 activation