Chemokines CCL20, CXCL1, IL-8, and TFF1 are the downstream targets of the IL-17B–IL-17RB signaling. (A) Summary of cDNA microarray analyses. Total of 71 genes expressed at least 2-fold higher in IL-17RB–overexpressing HPAC cells and 2-fold lower in IL-17RB–depleted CFPAC-1 cells compared with the proper control were identified by Affymetrix microarray analyses. (B) Four chemokines, CCL20, CXCL1, IL-8, and TFF1, were identified among the 71 genes. (C) qRT-PCR analysis to reconfirm the expression profile of the four chemokines in IL-17RB–depleted CFPAC-1, IL-17RB–, and ΔLBD-overexpressing HPAC cells. β-actin was used as an internal control. (D) Immunoblot analysis of IL-17RB and the four chemokines in shLacZ-transduced or IL-17RB–depleted CFPAC-1 cells, and lenti-neo, IL-17RB, or ΔLBD-overexpressing HPAC cells. GAPDH was used as a loading control. RE, relative expression. (E) Representative pictures of the IHC analyses of IL-17RB and TFF1 in serial sections of a PDAC case. Boxes show the enlarged area of IL-17RB high (+++) and negative (−) regions. (F) Correlation between TFF1 and IL-17RB in 111 pancreatic cancer cases from IHC assays. χ² test was used. (G) mRNA expression of the four chemokines were measured by RT-qPCR in CFPAC-1 cells treated with 50 ng/ml rIL17B for 0, 1, and 3 h after serum-starvation. β-actin was used as internal control. Data shown are means ± SD. *, P < 0.05; **, P < 0.01 (Student’s t test). (H) Protein expression of IL-17RB and the four chemokines were measured by immunoblotting in CFPAC-1 cells treated with 0, 20, or 50 ng/ml rIL17B for 6 h after serum starvation, respectively. GAPDH were used as internal controls. RE, relative expression. All experimental data was verified in at least two independent experiments.