Figure 5

Functional effect of cytokines and chemokines on the release of amylase activity and amylase mRNA content in HPG cell lines. (A) Amylase secretion assay from HPG cells under resting conditions and after stimulation with the ß-adrenergic agonist isoproterenol (10 µM) and calcium (2 mM) in the presence of: TFN-α (20 ng/mL), IL1-ß (5 ng/mL), IFN-γ (100 ng/mL), TGF-β (2 ng/mL) and CXCL12 (100 ng/mL). *p ≤ 0.05 and **p ≤ 0.01 by Wilcoxon signed-rank test respect to control. (B) Dose–response curves showing the inhibition of amylase secretion in presence of TFN-α. The solid line represents the sigmoidal fit to the data. The IC50 calculated for TFN-α was ~0.1 ng/mL. A representative experiment out of three is shown. The amylase activity in the absence of soluble factor was considered 100%. IC50 values were determined by variable-slope sigmoid function using GraphPad Prism version 5.04 for Windows (GraphPad Software, San Diego CA). (C) Dose–response curves showing the effect of TGF-β on amylase secretion. A representative experiment out of three is shown. The amylase activity in the absence of soluble factor was considered 100%. (D) Bar graph showing the relative amylase mRNA content in HPG cells cultured for 24 h in the presence of 20 ng/mL TNF-α, 100 pg/mL CXCL12 or 2 ng/mL TGF-β with respect to cells maintained in medium containing calcium (2 mM) and isoproterenol (10 µM). Data represent the mean ± SEM of 3 independent experiments. *p ≤ 0.05 and **p ≤ 0.01 by Wilcoxon signed-rank test.