APX3330 impairs the production of IL-6 that is crucial for the optimal CSR.
A, levels of secreted IL-6 in the supernatants of CH12F3 cells under CIT(−) or CIT(+) conditions in presence or absence of APE1 inhibitors. B, IL-6 detection in supernatants of not transfected or CH12F3 cells transfected with empty vector or with GFP-APE1WT, APE1C65S, or APE1E96A undergoing CSR. The data in A and B are representative of three independent experiments. C and D, percentages of CD19/IgA double-positive cells (C) and ng/ml of released IgA (D) by switching CH12F3 cells untreated, pretreated with APX3330, or pretreated with APX3330 and induced to CSR in presence of increasing amounts of exogenous recombinant IL-6 (rIL-6) ranging from 0.1 to 10,000 pg/ml. The data are representative of three independent experiments, and comparisons were performed between cells treated with APX3330 versus cells treated with APX330 in presence of IL-6. *, p < 0.05; **, p < 0.005; ***, p < 0.001.