Niclosamide inhibits expression of MUC5AC and SPDEF in Calu-3 cells. (A) Western blot indicating upregulation of TMEM16A in Calu-3 cells by IL-13 (20 ng/mL, 72 h) and inhibition of expression by niclosamide (1 µM). Blots were performed in triplicates. (B) RT-PCR analysis of the expression of MUC5AC, TMEM16A, and SAM pointed domain-containing ETS transcription factor (SPDEF) in Calu-3 airway epithelial cells. SPDEF is an integrator of goblet cell differentiation and pulmonary Th2 inflammation. (C) Low cycle numbers (20×) were chosen for quantification of expression by relating specific signals to expression of the housekeeper protein GAPDH. IL-13 (20 ng/mL) leads to upregulation of expression of MUC5AC, TMEM16A, and SPDEF. Niclosamide (Niclo, 1 µM, 72 h) strongly inhibits expression of MUC5AC, TMEM16A, and SPDEF. Mean ± SEM (number of assays). #,§ significant increase by IL-13 and inhibition by niclosamide, respectively (p < 0.05, ANOVA).