Epitope-Specific Anti-SerpinB3 Antibodies for SerpinB3 Recognition and Biological Activity Inhibition.

SerpinB3 is a serine protease inhibitor that plays a relevant role in disease progression and cancer by increasing fibrosis, cell proliferation, and invasion, besides conferring resistance to apoptosis. The mechanisms underlying these biological activities are not yet fully understood. The aim of this study was to generate antibodies directed against different SerpinB3 epitopes to better investigate their biological role. Five exposed epitopes were identified using the software DNASTAR Lasergene and the corresponding synthetic peptides were used for NZW rabbit immunization. Anti-P#2 and anti-P#4 antibodies were able to recognize both SerpinB3 and SerpinB4 by ELISA. Anti-P#5 antibody, produced against the reactive site loop of SerpinB3, showed the greatest specific reactivity for human SerpinB3. This antibody was able to recognize SerpinB3 at nuclear level, while anti-P#3 antibody recognized SerpinB3 only at cytoplasmic level, both by immunofluorescence and by immunohistochemistry. The biological activity of each antibody preparation was assessed in HepG2 cells overexpressing SerpinB3 and anti-P#5 antibody reduced proliferation by 12% cell and cell invasion by 75%, while trivial results were obtained with the other antibody preparations. These findings indicate that the reactive site loop of SerpinB3 is essential for the invasiveness features induced by this serpin and it could become a novel druggable target.

SERPINB3 and B4: From biochemistry to biology.

Human SERPINB3 and SERPINB4 are evolutionary duplicated serine/cysteine protease inhibitors. Genomic analysis indicates that these paralogous genes were encoded from independent loci arising from tandem gene duplication. Although the two molecules share 92% identity of their amino acid sequences, they are distinct in the Reactive Center Loop (RCL) including a hinge region and catalytic sequences which accounts for altered substrate specificity. Elevated expression of the two molecules has been reported to contribute to numerous pathological conditions such as inflammatory diseases and cancer. In this review, we focus on summarizing the biochemical features of SERPINB3/B4 and discussing the mechanistic basis for their biological functions and implications in human diseases.

Expression of SerpinB2 and SerpinB4 genes in nasal brushings in allergic rhinitis / 中国耳鼻咽喉头颈外科

OBJECTIVE To investigate the expression of SerpinB2 and SerpinB4 genes in cells from the nasal brushings in allergic rhinitis(AR) patients, and their relationships with eosinophil numbers in nasal brushings, serum total IgE level and severity of AR. METHODS Twenty nine control subjects and 59 AR patients[29 specific IgE positive AR(sIgE-P-AR) patients, 30 specific IgE negative self reported AR(sIgE-N-SR-AR) patients] were recruited. The samples of nasal brushings and peripheral blood were collected to detect SerpinB2 and SerpinB4 gene expression and eosinophil numbers in nasal brushings, and total IgE and allergen-specific IgE level in peripheral blood. RESULTS Expression of SerpinB2 and SerpinB4 genes in cells from nasal brushings were significantly higher in sIgE-P-AR [5.17(2.33-18.96), 0.6(0.355-1.08), respectively] and sIgE-N-SR-AR [3.27(1.59-13.4), 0.75(0.42-1.64), respectively] than that in control subjects[1.21(0.1-3.285), 0.29(0.165-0.505)] (sIgE-P-AR:P=0.013; sIgE-N-SR-AR:P=0.002). Expression level of SerpinB2 and SerpinB4 had no relationships with eosinophil numbers in nasal brushings and serum total IgE level. Expression of SerpinB2 in moderate/severe AR[4.74(2.68-47.5)] was significantly higher than that in mild AR[(1.333-5.603)](P=0.025); while expression of SerpinB4 in mild AR[3.95(2.6-7.59)] was significantly higher than that in moderate/ severe AR[2.83(0.715-5)](P=0.042). CONCLUSION SerpinB2 and SerpinB4 genes might be involved in the pathogenesis of AR, and their diagnostic values in AR deserve to be evaluated with larger samples.