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Summary: Background: SerpinB3 is a cysteine protease inhibitor involved in liver disease progression due to its proinflammatory and profibrogenic properties. The polymorphic variant SerpinB3‐PD (SB3‐PD), presents a substitution in its reactive centre loop, determining the gain of function. Aims: To disclose the clinical characteristics of a cohort of patients with cirrhosis in relation to the presence of SB3‐PD and to assess the effect of this genetic variant on fibrogenic and inflammatory cytokines in vitro. Methods: We assessed SB3 polymorphism in 90 patients with cirrhosis, prospectively followed up in our referral centre. We used HepG2 and HuH‐7 cells transfected to overexpress either wild‐type SB3 (SB3‐WT) or SB3‐PD to assess their endogenous effect, while LX2 and THP‐1 cells were treated with exogenous SB3‐WT or SB3‐PD proteins. Results: Patients carrying SB3‐PD had more severe portal hypertension and higher MELD scores, than patients carrying SB3‐WT. In multivariate analysis, SB3‐PD was an independent predictor of cirrhosis complications. Patients with SB3‐PD polymorphism presented with more severe liver fibrosis and inflammatory features. Hepatoma cells overexpressing SB3‐PD showed higher TGF‐β1 expression than controls. The addition of recombinant SB3‐PD induced an up‐regulation of TGF‐β1 in LX2 cells and a more prominent inflammatory profile in THP‐1 cells, compared to the effect of SB3‐WT protein. Conclusions: The polymorphic variant SB3‐PD is highly effective in determining activation of TGF‐β1 and inflammation in vitro. Patients with cirrhosis who carry SB3‐PD polymorphism may be more prone to develop severe liver disease progression. However, further validation studies are warranted to support the in vivo relevance of this polymorphism. [ABSTRACT FROM AUTHOR]

Epithelial-mesenchymal transition is believed to facilitate invasion and metastasis formation of epithelial tumour cells. SERPINB3 is a serine protease inhibitor, physiologically found in normal squamous epithelium but over-expressed in epithelial tumours and known to inhibit apoptosis. We tested the hypothesis that SERPINB3 has a role in invasion by modulating the epithelial-mesenchymal transition programme, using morphological, molecular and cell biology techniques on HepG2 cell clones transfected with the human SERPINB3 gene. The paracrine effect of this serpin was determined by the addition of exogenous recombinant SERPINB3 protein to HepG2 and MDCK cell line. SERPINB3 expression leads to changes in transfected cells morphology, characterized by clusters of loosely connected cells with elongated shape. Ultrastructural analysis confirmed the decrease of desmosomal junctions and widening of intercellular spaces. These alterations were associated with a reduction of E-cadherin and an increase of β-catenin, with a parallel increase of cell proliferation. SERPINB3 clones, untransfected HepG2 and MDCK cells treated with exogenous SERPINB3 expressed vimentin, undetectable in controls. SERPINB3 induced significant cell scattering, migration and invasiveness in untransfected cells. These effects were not dependent on the anti-protease activity of the protein, as documented by the results obtained with an active loop-deleted recombinant SERPINB3 protein. Scatter activity was inhibited by an anti-SERPINB3 antibody in a dose-dependent manner and SERPINB3-transfected cells formed a significantly higher number of colonies on soft agar than controls. In conclusion, the observed results indicate that SERPINB3 induces deregulation of adhesion processes and increases the invasiveness potential supported by features of epithelial-mesenchymal transition, acting at both the autocrine and the paracrine level. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]